Patent Publication Number: US-2012031130-A1

Title: Relay unit and air conditioning apparatus

Description:
TECHNICAL FIELD 
     The present invention relates to a relay unit and an air conditioning apparatus. The present invention particularly relates to simplification of a pipeline structure, size reduction of equipment, improvement of serviceability, and the like in the relay unit. 
     BACKGROUND ART 
     Hitherto, a multiple air conditioning apparatus for a building to which an air conditioning apparatus that performs a cooling operation or a heating operation by circulating a refrigerant between an outdoor unit, which is a heat source machine arranged outside a room, and an indoor unit arranged inside the room so as to convey cold or heat to a region to be air-conditioned such as indoors and the like is applied has been present (See Patent Literature 1, for example). As the refrigerant used in such an air conditioning apparatus, HFC refrigerants, for example, are widely used. Also, a natural refrigerant such as carbon dioxide (CO 2 ) and the like has begun to be used. 
     Also, an air conditioning apparatus of another configuration represented by a chiller system is used. In this air conditioning apparatus, cold or heat is generated in a heat source machine arranged outside the room, the cold or heat is transferred to a heat medium such as water, an anti-freezing fluid and the like by a heat exchanger arranged in the outdoor unit, and the heat medium is conveyed to a fan coil unit, a panel heater and the like, which is an indoor unit arranged in a region to be air-conditioned, so as to perform the cooling operation or heating operation (See Patent Literature 2, for example). Moreover, there is known a waste heat recovery type chiller in which four water pipelines are connected to a heat source machine so as to supply cold or heat. 
     CITATION LIST 
     Patent Literature 
     
         
         PTL 1: Japanese Unexamined Patent Application Publication No. 2-118372 (page 3,  FIG. 1 ) 
         PTL 2: Japanese Unexamined Patent Application Publication No. 2003-343936 (page 5,  FIG. 1 ) 
       
    
     SUMMARY OF INVENTION 
     Technical Problem 
     With a prior-art air conditioning apparatus, since a high-pressure refrigerant is conveyed to an indoor unit, a refrigerant charged amount becomes extremely large, and if the refrigerant leaks from a refrigerant circuit, harmful effects to the global environment such as deterioration of global warming may occur. Particularly, R410A has as large global warming potential of 1970, and if such a refrigerant is to be used, reduction of the refrigerant charged amount becomes extremely important from the viewpoint of global environmental protection. Also, if the refrigerant leaks into a living space, chemical properties of the refrigerant might affect the human body. Thus, measures such as more ventilation than necessary, installation of a leakage sensor, and the like are required, which lead to increases in costs and power consumption. 
     Such a problem can be solved by the chiller system as described in Patent Literature 2. However, since heat is exchanged performed between the refrigerant and water in the outdoor unit and the water is conveyed to the indoor unit, water conveying power becomes extremely large, and energy consumption is increased. Also, if both cold and heat are to be supplied by water or the like, the number of connected pipelines needs to be increased, which results in an increase in labor, time and costs required for installation work. Thus, to simplify the pipeline construction on the site, if a connection pipeline, valves, and a heat exchanger are contained on the device side in advance, the devices contained in the pipeline or valves become extremely large, which results in a cost increase and lowered productivity. 
     Thus, there is known a device in which a relay unit that exchanges heat between the refrigerant and water and the like is provided between the outdoor unit and the indoor unit so that the water conveying power does not become large. Here, the relay unit does not directly act on air conditioning of a target space, and in view of leakage of the refrigerant and the like, it is expected that the relay unit is connected by a pipeline to an indoor unit on each floor and installed in a space with many restrictions such as in the attic. Therefore, the pipeline structure is preferably simplified and made small. Particularly in the size reduction, making a thinner structure is preferable so that the relay unit can cope with an environment with harsh restrictions in one direction such as the height direction. However, the relay unit might handle cooling and heating energy at the same time, and if a pipeline handling the cooling energy is located close to the pipeline handling the heating energy through mere size-reduction, energy efficiency is deteriorated, and thus, measures are needed. Also, considering installation in a restricted space, consideration should be given so that maintenance and the like can be performed easily, for example. 
     The present invention was made in order to solve the above problems and an object thereof is to provide an air conditioning apparatus and the like which can be made thinner and allow for easy maintenance and time reduction while saving energy. 
     Solution to Problem 
     A relay unit according to the present invention is connected to one or a plurality of outdoor units and a plurality of indoor units by different pipeline systems, respectively, so as to exchange heat between a refrigerant circulating through the outdoor unit and a heat medium different from the refrigerant and to circulate the heat medium through the indoor unit, provided with a valve block unit to which a plurality of valve blocks integrated with at least a plurality of branch pipes connected to the indoor unit, a plurality of main pipes which become channels for the heat medium relating to the heat exchange, and a heat medium flow direction switching device that switches the main pipes to communicate with the branch pipe are connected. 
     Advantageous Effects of Invention 
     In the relay unit according to the present invention, since the valve block unit to which the plurality of valve blocks integrated with the plurality of branch pipes, the plurality of main pipes, and the heat medium flow direction switching device are connected, the pipeline can be simplified, the relay unit can be made thinner, and installation can be made effectively even in an environment with harsh restrictions such as in the attic. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is an outline circuit diagram illustrating a configuration of an air conditioning apparatus on which a valve block unit according to Embodiment 1 is mounted. 
         FIG. 2  is a refrigerant circuit diagram illustrating a flow of a refrigerant in a cooling-main operation mode of the air conditioning apparatus. 
         FIG. 3  is a refrigerant circuit diagram illustrating an outline configuration of the valve block unit in the air conditioning apparatus. 
         FIG. 4  is a perspective view illustrating the structure of the valve block unit in detail. 
         FIG. 4   a  is an exploded perspective view illustrating a state in which the valve block unit is exploded. 
         FIG. 4   b  is a view of the valve block unit when seen from a side face. 
         FIG. 5  is a longitudinal sectional view illustrating a sectional configuration of a valve block in a simplified manner. 
         FIG. 6  is an explanatory diagram for explaining a valve body. 
         FIG. 7  is an explanatory diagram for explaining a valve body. 
         FIG. 8  is an outline diagram illustrating a rotating state of the valve body. 
         FIG. 9  is an explanatory diagram for explaining connection of the valve block. 
         FIG. 10  is an explanatory diagram for explaining connection of the valve block. 
         FIG. 11   a  is a graph illustrating an example of a relationship between a pipeline distance and a temperature rise. 
         FIG. 11   b  is a graph illustrating an example of the relationship between the pipeline distance and the temperature rise. 
         FIG. 11   c  is a graph illustrating an example of the relationship between the pipeline distance and the temperature rise. 
         FIG. 12  is an explanatory diagram for explaining another means that suppresses thermal interference. 
         FIG. 13  is a view illustrating an appearance of a relay unit  3  according to Embodiment 2. 
         FIG. 14  is a view illustrating the connection of a valve block unit  300 . 
         FIG. 15  is a diagram illustrating an outline of a structure of a housing  600  that contains the relay unit  3 . 
         FIG. 16  is a diagram illustrating a relationship between the valve block unit  300  and a heat medium heat exchanger  15 . 
         FIG. 17  is a diagram illustrating another example of an installed form of the relay unit  3 . 
         FIG. 18  is a longitudinal sectional view illustrating a sectional configuration of the valve block constituting the valve block unit according to Embodiment 4 in a simplified manner. 
         FIG. 19  is an explanatory diagram for explaining the valve body. 
         FIG. 20  is a perspective view illustrating the structure of the valve block unit in detail. 
         FIG. 21  is an explanatory diagram for explaining the connection of the valve block. 
         FIG. 22  is an explanatory diagram for explaining the connection of the valve block. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Embodiments of the present invention will be described below. 
     Embodiment 1 
       FIG. 1  is an outline circuit diagram illustrating a configuration of an air conditioning apparatus  100  on which a valve block unit  300  according to Embodiment 1 of the present invention is mounted. On the basis of  FIG. 1 , a detailed configuration of the air conditioning apparatus  100  will be described. As shown in  FIG. 1 , an outdoor unit  1  and a relay unit  3  are connected through a first heat medium heat exchanger  15   a  and a second heat medium heat exchanger  15   b  and the relay unit  3  and an indoor unit  2  are connected through the first heat medium heat exchanger  15   a  and the second heat medium heat exchanger  15   b . Configurations and functions of each constituent device disposed in the air conditioning apparatus  100  will be described below. 
     [Outdoor Unit  1 ] 
     In the outdoor unit  1 , a compressor  10 , a four-way valve  11 , which is a refrigerant flow direction switching device, a heat-source side heat exchanger  12 , and an accumulator  17  are connected and contained in series by a refrigerant pipeline  4 . Also, in the outdoor unit  1 , a first connection pipeline  4   a , a second connection pipeline  4   b , a check valve  13   a , a check valve  13   b , a check valve  13   c , and a check valve  13   d  are disposed. By disposing the first connection pipeline  4   a , the second connection pipeline  4   b , the check valve  13   a , the check valve  13   b , the check valve  13   c , and the check valve  13   d , the flow direction of the heat-source-side refrigerant made to flow into the relay unit  3  can be made constant regardless of an operation required by the indoor unit  2 . 
     The compressor  10  is to suck in the heat-source-side refrigerant and to compress the heat-source-side refrigerant to bring it into a high-temperature high-pressure state and is preferably composed of an inverter compressor or the like capable of capacity control, for example. The four-way valve  11  is to perform switching between the flow of the heat-source-side refrigerant during a heating operation and the flow of the heat-source-side refrigerant during the cooling operation. The heat-source-side heat exchanger  12  functions as an evaporator during the heating operation, while it functions as a condenser during the cooling operation so as to exchange heat between the air supplied from a blower such as a fan, not shown, and the heat-source-side refrigerant and to evaporate and gasify the heat-source-side refrigerant or to condense and liquefy the same. The accumulator  17  is disposed in the suction side of the compressor  10  and stores an excess refrigerant. 
     The check valve  13   d  is disposed in the refrigerant pipeline  4  between the relay unit  3  and the four-way valve  11  so as to allow the flow of the heat-source-side refrigerant only in a predetermined direction (direction from the relay unit  3  to the outdoor unit  1 ). The check valve  13   a  is disposed in the refrigerant pipeline  4  between the heat-source side heat exchanger  12  and the relay unit  3  so as to allow the flow of the heat-source-side refrigerant only in a predetermined direction (direction from the outdoor unit  1  to the relay unit  3 ). The check valve  13   b  is disposed in the first connection pipeline  4   a  so as to allow the flow of the heat-source-side refrigerant only in the direction from the upstream side of the check valve  13   d  to the upstream side of the check valve  13   a . The check valve  13   c  is disposed in the second connection pipeline  4   b  so as to allow the flow of the heat-source-side refrigerant only in the direction from the downstream side of the check valve  13   d  to the downstream side of the check valve  13   a.    
     The first connection pipeline  4   a  connects the refrigerant pipeline  4  on the upstream side of the check valve  13   d  and the refrigerant pipeline  4  on the upstream side of the check valve  13   a  to each other in the outdoor unit  1 . The second connection pipeline  4   b  connects the refrigerant pipeline  4  on the downstream side of the check valve  13   d  and the refrigerant pipeline  4  on the downstream side of the check valve  13   a  to each other in the outdoor unit  1 . In  FIG. 1 , the example in which the first connection pipeline  4   a , the second connection pipeline  4   b , the check valve  13   a , the check valve  13   b , the check valve  13   c , and the check valve  13   d  are disposed is shown, but that example is not limiting, and they do not necessarily have to be disposed. 
     [Indoor Unit  2 ] 
     On the indoor units  2 , use-side heat exchangers  26  are mounted, respectively. This use-side heat exchanger  26  is connected to a heat medium flow control device  24  and a heat medium flow direction switching device  23  of the relay unit  3  through the pipeline  5 . This use-side heat exchanger  26  exchanges heat between the air supplied from the blower such as a fan, not shown, and a heat medium and generates air for heating or air for cooling to be supplied to a region to be air-conditioned. 
     In  FIG. 1 , the example in which four indoor units  2  are connected to the relay unit  3  is shown, in which an indoor unit  2   a , an indoor unit  2   b , an indoor unit  2   c , and an indoor unit  2   d  from the lower side in the figure are shown. Corresponding to the indoor units  2   a  to  2   d , the use-side heat exchanger  26  is also shown from the lower side in the figure as a use-side heat exchanger  26   a , a use-side heat exchanger  26   b , a use-side heat exchanger  26   c , and a use-side heat exchanger  26   d . The number of connected indoor units  2  is not limited to four units shown in  FIG. 1 . 
     [Relay Unit  3 ] 
     The relay unit  3  is composed of a gas-liquid separator  14 , a expansion device  16   e , two heat medium heat exchangers  15  (the first heat medium heat exchanger  15   a  and the second heat medium heat exchanger  15   b ), four expansion devices  16 , two heat medium delivery devices  21 , four heat medium flow direction switching devices  22 , four heat medium flow direction switching devices  23 , and four heat medium flow control devices  24  are disposed. 
     The gas-liquid separator  14  is connected to the single refrigerant pipeline  4  connected to the outdoor unit  1  and the two refrigerant pipelines  4  connected to the first heat medium heat exchanger  15   a  and the second heat medium heat exchanger  15   b  so as to separate the heat-source-side refrigerant supplied from the outdoor unit  1  to a vapor-state refrigerant and a liquid refrigerant. The expansion device  16   e  is disposed between the refrigerant pipeline  4  that connects the expansion device  16   a  and the expansion device  16   b  to each other and the gas-liquid separator  14  and functions as a decompression valve or an expansion device so as to decompress and expand the heat-source-side refrigerant. The expansion device  16   e  is preferably composed of a valve with variably controllable opening degree such as an electronic expansion valve, for example. 
     The two heat medium heat exchangers  15  (the first heat medium heat exchanger  15   a  and the second heat medium heat exchanger  15   b ) function as condensers or evaporators, exchange heat between the heat-source-side refrigerant and the heat medium and supply cold or heat generated in the outdoor unit  1  to the indoor units  2 . In the flow of the heat-source-side refrigerant, the first heat medium heat exchanger  15   a  is disposed between the gas-liquid separator  14  and the expansion device  16   d . In the flow of the heat-source-side refrigerant, the second heat medium heat exchanger  15   b  is disposed between the expansion device  16   a  and the expansion device  16   c.    
     The four expansion devices  16  (the expansion devices  16   a  to  16   d ) function as decompression valves or expansion valves and decompress and expand the heat-source-side refrigerant. The expansion device  16   a  is disposed between the expansion device  16   a  and the second heat medium heat exchanger  15   b . The expansion device  16   b  is disposed in parallel with the expansion device  16   a . The expansion device  16   c  is disposed between the second heat exchanger  15   b  and the outdoor unit  1 . The expansion device  16   d  is disposed between the first heat exchanger  15   a  and the expansion device  16   a  as well as the expansion device  16   b . The four expansion devices  16  are preferably composed of devices with variably controllable opening degree such as electronic expansion valve, for example. 
     The two heat medium delivery devices  21  (the first heat medium delivery device  21   a  and the second heat medium delivery device  21   b ) are composed of pumps and the like and pressurize and circulate the heat medium guided through the pipeline  5 . The first heat medium delivery device  21   a  is disposed in the pipeline  5  between the first heat medium heat exchanger  15   a  and the heat medium flow direction switching device  22 . The second heat medium delivery device  21   b  is disposed in the pipeline  5  between the second heat medium heat exchanger  15   b  and the heat medium flow direction switching device  22 . The types of the first heat medium delivery device  21   a  and the second heat medium delivery device  21   b  are not particularly limited but may be configured by a capacity-controllable pump or the like. 
     The four heat medium flow direction switching devices  22  (the heat medium flow direction switching devices  22   a  to  22   d ) are composed of three-way valves and switch the channels of the heat medium. The heat medium flow direction switching devices  22  are disposed in the number (four, here) according to the number of the installed indoor units  2 . As for the heat medium flow direction switching devices  22 , one of the three ways is connected to the first heat medium heat exchanger  15   a , another one of the three ways to the second heat medium heat exchanger  15 , and the rest of the three ways to the heat medium flow control device  24 , respectively, and they are disposed on the inlet side of a heat medium channel of the use-side heat exchanger  26 . Corresponding to the indoor units  2 , they are shown as the heat medium flow direction switching device  22   a , the heat medium flow direction switching device  22   b , the heat medium flow direction switching device  22   c , and the heat medium flow direction switching device  22   d  from the lower side in the figure. 
     The four heat medium flow direction switching devices  23  (the heat medium flow direction switching devices  23   a  to  23   d ) are composed of three-way valves and switch the channels of the heat medium. The heat medium flow direction switching devices  23  are disposed in the number (four, here) according to the number of the installed indoor units  2 . As for the heat medium flow direction switching devices  23 , one of the three ways is connected to the first heat medium heat exchanger  15   a , another one of the three ways to the second heat medium heat exchanger  15   b , and the rest of the three ways to the use-side heat exchanger  26 , respectively, and they are disposed on the outlet side of a heat medium channel of the use-side heat exchanger  26 . Corresponding to the indoor units  2 , they are shown as the heat medium flow direction switching valve  23   a , the c heat medium flow direction switching valve  23   b , the heat medium flow direction switching valve  23   c , and the heat medium flow direction switching valve  23   d  from the lower side in the figure. 
     The four heat medium flow control devices  24  (the heat medium flow control devices  24   a  to  24   d ) are composed of two-way valves and switch the channel of the heat medium. The heat medium flow control devices  24  are disposed in the number (four, here) according to the number of the installed indoor units  2 . One side of each of the heat medium flow control devices  24  is connected to the use side heat exchanger  26 , while the other side is connected to the heat medium flow direction switching device  22 , and they are disposed on the inlet side of the heat medium channel of the use-side heat exchanger  26 . Corresponding to the indoor units  2 , they are shown as the heat medium flow control device  24   a , the heat medium flow control device  24   b , the heat medium flow control device  24   c , and the heat medium flow control device  24   d  from the lower side in the figure. 
     Also, in the relay unit  3 , two first heat medium temperature detecting means  31 , two second heat medium temperature detecting means  32 , four third heat medium temperature detecting means  33 , four fourth heat medium temperature detecting means  34 , a first refrigerant temperature detecting means  35 , a refrigerant pressure detecting means  36 , a second refrigerant temperature detecting means  37 , and a third refrigerant temperature detecting means  38  are disposed. Information detected by these detecting means is sent to a controller, not shown, that controls the operation of the air conditioning apparatus  100  and used for control of driving frequencies of the compressor  10  and the heat medium delivery device  21 , switching of the channel for the heat medium flowing through the pipeline  5  and the like. 
     The two first heat medium temperature detecting means  31  (a first heat medium temperature detecting means  31   a  and a first heat medium temperature detecting means  31   b ) detect the temperature of the heat medium flowing out of the heat medium heat exchanger  15 , that is, the heat medium temperature at the outlet of the heat medium heat exchanger  15  and are preferably composed of thermistors or the like. The first heat medium temperature detecting means  31   a  is disposed in the pipeline  5  on the inlet side of the first heat medium delivery device  21   a . The second heat medium temperature detecting means  31   b  is disposed in the pipeline  5  on the inlet side of the second heat medium delivery device  21   b.    
     The two second heat medium temperature detecting means  32  (a second heat medium temperature detecting means  32   a  and a second heat medium temperature detecting means  32   b ) detect the temperature of the heat medium flowing into the heat medium heat exchanger  15 , that is, the heat medium temperature at the inlet of the heat medium heat exchanger  15  and are preferably composed of thermistors or the like. The second heat medium temperature detecting means  32   a  is disposed in the pipeline  5  on the inlet side of the first heat medium heat exchanger  15   a . The second heat medium temperature detecting means  32   b  is disposed in the pipeline  5  on the inlet side of the second heat medium heat exchanger  15   b.    
     The four third heat medium temperature detecting means  33  (third heat medium temperature detecting means  33   a  to  33   d ) are disposed on the inlet side of the heat medium channel of the use-side heat exchanger  26  and detect the temperature of the heat medium flowing into the use-side heat exchanger  26 , and the detecting means is preferably composed of a thermistor or the like. The third heat medium temperature detecting means  33  are disposed in number (four, here) according to the installed number of the indoor units  2 . Corresponding to the indoor units  2 , they are shown as the third heat medium temperature detecting means  33   a , the third heat medium temperature detecting means  33   b , the third heat medium temperature detecting means  33   c , and the third heat medium temperature detecting means  33   d  from the lower side in the figure. 
     The four fourth heat medium temperature detecting means  34  (fourth heat medium temperature detecting means  34   a  to  34   d ) are disposed on the outlet side of the heat medium channel of the use-side heat exchanger  26  and detect the temperature of the heat medium flowing out of the use-side heat exchanger  26 , and the detecting means is preferably composed of a thermistor or the like. The fourth heat medium temperature detecting means  34  are disposed in number (four, here) according to the installed number of the indoor units  2 . Corresponding to the indoor units  2 , they are shown as the fourth heat medium temperature detecting means  34   a , the fourth heat medium temperature detecting means  34   b , the fourth heat medium temperature detecting means  34   c , and the fourth heat medium temperature detecting means  34   d  from the lower side in the figure. 
     The first refrigerant temperature detecting means  35  is disposed at the outlet side of the heat-source-side refrigerant channel of the first heat medium heat exchanger  15   a  and detects the temperature of the heat-source-side refrigerant flowing out of the first heat medium heat exchanger  15   a , and the detecting means is preferably composed of a thermistor or the like. The refrigerant pressure detecting means  36  is disposed on the outlet side of the heat-source-side refrigerant channel of the first heat medium heat exchanger  15   a  and detects a pressure of the heat-source-side refrigerant flowing out of the first heat medium heat exchanger  15   a  and can be constituted by a pressure sensor or the like. 
     The second refrigerant temperature detecting means  37  is disposed on the inlet side of the heat-source-side refrigerant channel of the second heat medium heat exchanger  15   b  and detects the temperature of the heat-source-side refrigerant flowing into the second heat medium heat exchanger  15   b , and the detecting means is preferably composed of a thermistor or the like. The third refrigerant temperature detecting means  38  is disposed on the outlet side of the heat-source-side refrigerant channel of the second heat medium heat exchanger  15   b  and detects a temperature of the heat-source-side refrigerant flowing out of the second heat medium heat exchanger  15   b , and the detecting means is preferably composed of a thermistor or the like. 
     The pipeline  5  through which the heat medium is guided is composed of a pipeline connected to the first heat medium heat exchanger  15   a  (hereinafter referred to as a pipeline  5   a ) and a pipeline connected to the second heat medium heat exchanger  15   b  (hereinafter referred to as, a pipeline  5   b ). The pipeline  5   a  and the pipeline  5   b  are branched in accordance with the number (here, branched to four each) of the indoor units  2  connected to the relay unit  3 . And the pipeline  5   a  and the pipeline  5   b  are connected by the heat medium flow direction switching device  22  and the heat medium flow direction switching device  23 . By controlling the heat medium flow direction switching device  22  and the heat medium flow direction switching device  23 , it is determined whether the heat medium guided through the pipeline  5   a  is made to flow into the use-side heat exchanger  26  or the heat medium guided through the pipeline  5   b  is made to flow into the use-side heat exchanger  26 . 
     In this air conditioning apparatus  100 , the compressor  10 , the four-way valve  11 , the heat-source side heat exchanger  12 , the first heat medium heat exchanger  15   a , and the second heat medium heat exchanger  15   b  are connected by the refrigerant pipeline  4  in series in the order so as to constitute a refrigeration cycle. Also, the first heat medium heat exchanger  15   a , the first heat medium delivery device  21   a , and the use-side heat exchanger  26  are connected by the pipeline  5   a  in series in the order so as to constitute a heat medium circulation circuit. Similarly, the second heat medium heat exchanger  15   b , the second heat medium delivery device  21   b , and the use-side heat exchanger  26  are connected by the pipeline  5   b  in series in the order so as to constitute a heat medium circulation circuit. That is, a plurality of use-side heat exchangers  26  are connected in parallel with each of the heat medium heat exchangers  15  so as to form plural systems of the heat medium circulation circuits. 
     That is, the outdoor unit  1  and the relay unit  3  are connected to each other through the first heat medium heat exchanger  15   a  and the second heat medium heat exchanger  15   b  disposed in the relay unit  3 . And the relay unit  3  and the indoor units  2  are connected by the first heat medium heat exchanger  15   a  and the second heat medium heat exchanger  15   b  so that the heat-source-side refrigerant, which is the primary-side refrigerant which circulates through the refrigeration cycle in the first heat medium heat exchanger  15   a  and the second heat medium heat exchanger  15   b , exchange heat with the heat medium, which is the secondary-side refrigerant which circulates through the heat medium circulation circuit. 
     Here, the type of the refrigerant used in the refrigeration cycle and the heat medium circulation circuit will be described. 
     For the refrigeration cycle, a nonazeotropic refrigerant mixture such as R407c, a near-azeotropic refrigerant mixture such as R410A, a single refrigerant such as R22 and the like can be used. Also, a natural refrigerant such as carbon dioxide, hydrocarbon and the like may be used. By using the natural refrigerant as the heat-source-side refrigerant, an advantage that a global warming effect caused by leakage of the refrigerant can be suppressed is obtained. 
     The heat medium-circulation circuit is connected to the use-side heat exchanger  26  of the indoor unit  2  as described above. Thus, in the air conditioning apparatus  100 , considering the case of leakage of the heat medium into a room where the indoor unit  2  is installed or the like, use of the heat medium with high safety is premised. Therefore, for the heat medium, water, an anti-freezing solution, a mixed liquid of water and the anti-freezing solution and the like can be used, for example. According to this configuration, refrigerant leakage caused by freezing or corrosion can be prevented even at a low outside temperature, and high reliability can be obtained. Also, if the indoor unit  2  is installed in a place where moisture should be avoided such as a computer room, a fluorine inactive liquid with high heat insulation can be used as the heat medium. 
     This air conditioning apparatus  100  is, on the basis of an instruction from each indoor unit  2 , capable of the cooling operation or the heating operation with the indoor unit  2  thereof. That is, the air conditioning apparatus  100  is capable of performing the same operation with all the indoor units  2  or of performing different operations with each of the indoor units  2 . There are four operation modes executed by the air conditioning apparatus  100  include a cooling-only operation mode in which all the driving indoor units  2  perform the cooling operation, a heating-only operation mode in which all the driving indoor units  2  perform the heating operation, a cooling-main operation mode in which a cooling load is larger, and a heating-main operation mode in which a heating load is larger. In each of the operation modes, the cooling-main operation mode in which the cooling and the heating are mixed and the cooling load shares the most will be described. 
     [Cooling-Main Operation Mode] 
       FIG. 2  is a refrigerant circuit diagram illustrating the flow of the refrigerant during the cooling-main operation mode of the air conditioning apparatus  100 . In  FIG. 2 , using an example in which a heating load is generated in the use-side heat exchanger  26   a  and a cooling load is generated in the use-side heat exchangers  26   b  to  26   d , the cooling-main operation mode will be described. In  FIG. 2 , the pipeline expressed by a bold line indicates a pipeline through which the refrigerant (heat-source-side refrigerant and heat medium) circulates. Also, the flow direction of the heat-source-side refrigerant is indicated by a solid-line arrow, while the flow direction of the heat medium by a broken-line arrow. 
     First, the flow of the heat-source-side refrigerant in the refrigeration cycle will be described. 
     The low-temperature and low-pressure refrigerant is compressed by the compressor  10  and discharged as a high-temperature high-pressure gas refrigerant. The high-temperature high-pressure gas refrigerant discharged from the compressor  10  passes through the four-way valve  11  and flows into the heat-source side heat exchanger  12 . Then, the refrigerant is condensed while radiating heat to the outdoor air in the heat-source side heat exchanger  12  and becomes a gas-liquid two-phase refrigerant. The gas-liquid two-phase refrigerant having flowed out of the heat-source side heat exchanger  12  flows out of the outdoor unit  1  via the check valve  13   a  and flows into the relay unit  3  via the refrigerant pipeline  4 . The gas-liquid two-phase refrigerant having flowed into the relay unit  3  flows into the gas-liquid separator  14  and is separated to a gas refrigerant and a liquid refrigerant. 
     The gas refrigerant having been separated in the gas-liquid separator  14  flows into the first heat medium heat exchanger  15   a . The gas refrigerant having flowed into the first heat medium heat exchanger  15   a  is condensed and liquefied while radiating heat to the heat medium circulating through the heat medium circulation circuit and becomes a liquid refrigerant. The liquid refrigerant having flowed out of the first heat medium heat exchanger  15   a  passes through the expansion device  16   d . On the other hand, the liquid refrigerant separated in the gas-liquid separator  14  passes through the expansion device  16   e , is condensed and liquefied in the first heat medium heat exchanger  15   a  but merges with the liquid refrigerant having passed through the expansion device  16   d , is throttled by the expansion device  16   a  and expanded and flows into the second heat medium heat exchanger  15   b  as the low-temperature and low-pressure gas-liquid two-phase refrigerant. 
     This gas-liquid two-phase refrigerant absorbs heat from the heat medium circulating through the heat medium circulation circuit in the second heat medium heat exchanger  15   b  working as an evaporator so as to cool the heat medium and becomes a low-temperature and low-pressure gas refrigerant. The gas refrigerant having flowed out of the second heat medium heat exchanger  15   b  passes through the expansion device  16   c  and then, flows out of the relay unit  3  and flows into the outdoor unit  1  via the refrigerant pipeline  4 . The refrigerant having flowed into the outdoor unit  1  passes through the check valve  13   d  and is sucked into the compressor  10  again via the four-way valve  11  and the accumulator  17 . The expansion device  16   b  has a small opening degree so that the refrigerant does not flow therethrough, and the expansion device  16   c  is in the full open state so that a pressure loss does not occur. 
     Subsequently, the flow of the heat medium in the heat medium circulation circuit will be described. 
     The heat medium having been pressurized by the first heat medium delivery device  21   a  and flowed out passes through the heat medium flow control device  24   a  via the heat medium flow direction switching device  22   a  and flows into the use-side heat exchanger  26   a . Then, in the use-side heat exchanger  26   a , the heat medium gives heat to the indoor air and performs heating of the region to be air-conditioned such as the inside of the room where the indoor unit  2  is installed. Also, the heat medium having been pressurized by the second heat medium delivery device  21   b  and flowed out passes through the heat medium flow control devices  24   b  to  24   d  via the heat medium flow direction switching devices  22   b  to  22   d  and flows into the use-side heat exchangers  26   b  to  26   d . Then, in the use-side heat exchangers  26   b  to  26   d , the heat medium absorbs heat from the indoor air and performs cooling of the region to be air-conditioned such as the inside of the room where the indoor unit  2  is installed. 
     The heat medium used for the heating operation flows into the use-side heat exchanger  26   a  only in a flow rate required to cover the air-conditioning load required in the region to be air-conditioned by means of an action of the heat medium flow control device  24   a . Then, the heat medium having performed the heating operation flows into the first heat medium heat exchanger  15   a  via the heat medium flow direction switching device  23   a  and is sucked into the first heat medium delivery device  21   a  again. 
     The heat medium used for the cooling operation flows into the use-side heat exchangers  26   b  to  26   d  only in a flow rate required to cover the air-conditioning load required in the region to be air-conditioned by means of an action of the heat medium flow control devices  24   b  to  24   d . Then, the heat medium having performed the cooling operation flows into the second heat medium heat exchanger  15   b  via the heat medium flow direction switching device  23   b  and is sucked into the second heat medium delivery device  21   b  again. 
       FIG. 3  is a refrigerant circuit diagram illustrating an outline configuration of a valve block unit  300  in the air conditioning apparatus  100 . On the basis of  FIG. 3 , the configuration of the valve block unit  300  will be described. In Embodiment 1, a portion surrounded by a broken line in  FIG. 3  is made into a block and constituted as the valve block unit  300 . As is known from  FIG. 3 , the valve block unit  300  is composed of the heat medium flow direction switching device  22 , the heat medium flow direction switching device  23 , the heat medium flow control device  24 , a cooling outward-flow main pipe  307 , a heating outward-flow main pipe  308 , a cooling return-flow main pipe  305 , a heating return-flow main pipe  306 , a first branch pipe  301 , and a second branch pipe  302 . 
     Each of the cooling outward-flow main pipe  307 , the heating outward-flow main pipe  308 , the cooling return-flow main pipe  305 , the heating return-flow main pipe  306 , the first branch pipe  301 , and the second branch pipe  302  constitutes a part of the above-described pipeline  5 . Also, the first branch pipe  301  constitutes a channel that guides the heat medium to the load side (indoor unit  2 ), and the second branch pipe  302  constitutes a channel through which the heat medium returns from the load side (indoor unit). The first branch pipe  301  and the second branch pipe  302  will be described in detail in  FIG. 5 . 
     The heat medium flow direction switching device  22  and the heat medium flow direction switching device  23  correspond to at least one flow direction switching means having a valve body. The cooling outward-flow main pipe  307  corresponds to a first pipeline through which guiding of the heat medium is selectively switched by the heat medium flow direction switching device  22 . The heating outward-flow main pipe  308  corresponds to a second pipeline through which guiding of the heat medium is selectively switched by the heat medium flow direction switching device  22 . The cooling return-flow main pipe  305  corresponds to the first pipeline through which guiding of the heat medium is selectively switched by the heat medium flow direction switching device  23 . The heating return-flow main pipe  306  corresponds to the second pipeline through which guiding of the heat medium is selectively switched by the heat medium flow direction switching device  23 . 
     That is the valve block unit  300  according to Embodiment 1 is constituted by four valve blocks, in which one set is composed of the heat medium flow direction switching device  22 , the cooling outward-flow main pipe  307 , the heating outward-flow main pipe  308 , and the branch pipe  301  and another set is composed of the heat medium flow direction switching device  23 , the cooling return-flow main pipe  305 , the heating return-flow main pipe  306 , and the branch pipe  302  are formed, are connected. In  FIG. 3 , a state in which the heat medium flow control device  24  is disposed in the valve block unit  300  is illustrated as an example, but the heat medium flow control device  24  is not indispensable or may be disposed on the branch pipe  302  side. 
     This valve block unit  300  is preferably formed by a material with small heat conductivity (a metal material or a plastic material) as a main material since hot water and cold water flow through the inside, thermal interference occurs, which incurs performance deterioration. The metal material includes stainless, brass, bronze, aluminum and the like. The plastic material includes PPS (polyphenylenesulfide), PPE (polyphenyleneether), cross-linked polyethylene or polybutene and the like, for example. In order to reduce the weight of the valve block unit  300 , the plastic material is used as a main material further preferably. 
       FIG. 4  is a perspective view illustrating the structure of the valve block unit  300  in detail. On the basis of  FIG. 4 , the configuration of the valve block unit  300  will be described in more detail. The valve block unit  300  shown in  FIG. 4  has four valve blocks  350  (valve block  350   a  to valve block  350   d ) connected as shown in  FIG. 3 , which are connected to the four indoor units  2 . The valve block  350  has the heat medium flow direction switching device  22 , the heat medium flow direction switching device  23 , and the heat medium flow control device  24 , which covers one branch portion. That is, the valve block unit  300  according to the Embodiment 1 has four branches. 
       FIG. 4   a  is an exploded perspective view illustrating a state in which the valve block unit  300  is exploded. On the basis of  FIG. 4   a , assembling of the valve block unit  300  branching into four parts will be described. As described above, the valve block unit  300  is formed by the valve block  350   a , the valve block  350   b , the valve block  350   c , and the valve block  350   d  connected to each other. 
     Then, the cooling outward-flow main pipe  307  (illustrated as a cooling outward-flow main pipe  307   a , a cooling outward-flow main pipe  307   b , a cooling outward-flow main pipe  307   c , and a cooling outward-flow main pipe  307   d  from the right side in the figure), the heating outward-flow main pipe  308  (illustrated as a heating outward-flow main pipe  308   a , a heating outward-flow main pipe  308   b , a heating outward-flow main pipe  308   c , and a heating outward-flow main pipe  308   d  from the right side in the figure), the cooling return-flow main pipe  305  (illustrated as a cooling return-flow main pipe  305   a , a cooling return-flow main pipe  305   b , a cooling return-flow main pipe  305   c , and a cooling return-flow main pipe  305   d  from the right side in the figure), and the heating return-flow main pipe  306  (illustrated as a heating return-flow main pipe  306   a , a heating return-flow main pipe  306   b , a heating return-flow main pipe  306   c , and a heating return-flow main pipe  306   d  from the right side in the figure) of each valve block  350  are connected to each other, respectively, so as to form the main pipe (pipeline  5 ). 
     One end of each main pipe (the cooling outward-flow main pipe  307 , the heating outward-flow main pipe  308 , the cooling return-flow main pipe  305 , and the heating return-flow main pipe  306 ) is formed into a female shape and the other end is formed into a male shape capable of connecting to the female-shaped end so that the valve blocks  350  can be connected. And on the cooling outward-flow main pipe  307   a  and the heating outward-flow main pipe  308   a  of the valve block  350   a  located at one of the both ends of the valve block unit  300 , caps  318  that cap them are disposed. On the other hand, on the cooling return-flow main pipe  305   d  and the heating return-flow main pipe  306   d  of the valve block  350   d  located at the other of the both ends of the valve block unit  300 , caps  319  that cap them are disposed. 
     The cap  318  and the cap  319  are used for two main pipes of the four main pipes. That is, in the valve block  350   a , the cooling outward-flow main pipe  307   a  and the heating outward-flow main pipe  308   a  are capped with the caps  318 , while the cooling return-flow main pipe  305   a  and the heating return-flow main pipe  306   a  are not capped with the caps  319 . The heating return-flow main pipe  306   a  is connected to the suction side of the heating-side pump (first heat medium delivery device  21   a ) and the cooling return-flow main pipe  305   a  is connected to the suction side of the cooling side pump (second heat medium delivery device  21   b ), respectively. 
     On the other hand, in the valve block  350   d , the cooling return-flow main pipe  305   d  and the heating return-flow main pipe  306   d  are capped with the caps  319 , while the cooling outward-flow main pipe  307   d  and the heating outward-flow main pipe  308   d  are not capped with the caps  318 . The heating outward-flow main pipe  308   d  is connected to the discharge side of the heating-side pump and the cooling outward-flow main pipe  307   d  is connected to the discharge side of the cooling side pump, respectively. The cap  318  and the cap  319  have shapes corresponding to the shape of the end of each pipeline. As shown in  FIG. 4   a , the cap  318  has a shape according to the male pipeline end (a lid shape so as to cover the pipeline end) and the cap  319  has a shape according to the female pipeline end (a plug shape to be fitted in the pipeline). 
     On the other hand, in the valve block  350   d , the cooling return-flow main pipe  305   d  and the heating return-flow main pipe  306   d  are capped with the caps  319 , while the cooling outward-flow main pipe  307   d  and the heating outward-flow main pipe  308   d  are not capped with the caps  318 . The heating outward-flow main pipe  308   d  is connected to the discharge side of the heating-side pump and the cooling outward-flow main pipe  307   d  is connected to the discharge side of the cooling side pump, respectively. The cap  318  and the cap  319  have shapes corresponding to the shape of the end of each pipeline. As shown in  FIG. 4   a , the cap  318  has a shape according to the male pipeline end (a lid shape so as to cover the pipeline end). As shown in  FIG. 4   b , a lug is disposed on the cap end so that it can be fixed with a screw and screwed into the valve block main body. The cap  319  has a shape according to the female pipeline end and is fixed by a screw head as shown in  FIG. 4   b.    
     As is known from this  FIG. 4   a , the valve block unit  300  is capable of switching the heat medium flow direction and forms each main pipe by connecting a plurality of valve blocks  350 . According to this valve block unit  300 , pipelines around the valve can be simplified as compared with a device in which the flow direction switching device and the pipeline are provided separately. Therefore, the unit on which the valve block unit  300  is mounted (the relay unit  3  in Embodiment 1) can be made compact. A sacrificed hole  321  shown in  FIG. 4   a  is a hole required for forming the channel of the valve block  350 . Since the sacrificed hole  321  needs to be independent among the valve blocks  350 , it is shut off by a joint  320  in  FIG. 4   a.    
       FIG. 5  is a longitudinal sectional view illustrating a sectional configuration of the valve block  350  in a simplified manner. On the basis of  FIG. 5 , the configuration of the valve block  350  constituting the valve block unit  300  will be described along with the flow of the heat medium. The first branch pipe  301  corresponds to a third pipeline that selectively communicates with the cooling outward-flow main pipe  307  or the heating outward-flow main pipe  308 . That is, the first branch pipe  301  communicates with the cooling outward-flow main pipe  307  or the heating outward-flow main pipe  308  selectively switched by the heat medium flow direction switching device  22 . The second branch pipe  302  corresponds to the third pipeline that selectively communicates with the cooling return-flow main pipe  305  or the heating return-flow main pipe  306 . That is, the second branch pipe  302  communicates with the cooling return-flow main pipe  305  or the heating return-flow main pipe  306  selectively switched by the heat medium flow direction switching device  23 . That is, the second branch pipe  302  communicates with the cooling return-flow main pipe  305  or the heating return-flow main pipe  306  selectively switched by the heat medium flow direction switching device  23 . 
     Here, as shown in  FIG. 5 , the temperature detecting means  33  and the temperature detecting means  34  are incorporated in the pipeline. The temperature detecting means  33  is incorporated in the channel in the block. For the branch pipes  301  and  302 , a copper pipe is used, and if the valve block  350  is made of plastic, the branch pipes  301  and  302  are brazed and connected to an extension pipeline during an installation work. At this time, since it is likely that the plastic of the valve block  350  is melted by heat conduction, the brazing is performed in a state in which the branch pipes  301  and  302  are removed from the valve block  350 . In the case of fixation on the surface of the pipeline as in the prior-art temperature detecting means, the temperature detecting means is likely to be removed during brazing, and re-installation of the temperature detecting means might be forgotten when the work is completed. Thus, reliability of the device is lowered. Then, as shown in  FIG. 5 , by embedding the temperature detecting means  33  and  34  in the pipeline or in the channel, the risk of removal of the temperature detecting means can be eliminated, and reliability of the device is improved. 
     As is known from  FIG. 4   a , the valve block unit  300  is capable of switching the heat medium channel and also forms each main pipe by connecting the plurality of valve blocks  350 . According to this valve block unit  300 , as compared with the device in which the flow direction switching device and the pipeline are provided separately, the pipeline around the valve can be simplified. Therefore, the unit on which the valve block unit  300  is mounted (the relay unit  3  in Embodiment 1) can be made compact. 
       FIG. 5  is a longitudinal sectional view illustrating a sectional configuration of the valve block  350  in a simplified manner. On the basis of  FIG. 5 , the configuration of the valve block  350  constituting the valve block unit  300  will be described along with the flow of the heat medium. The first branch pipe  301  corresponds to the third pipeline that selectively communicates with the cooling outward-flow main pipe  307  or the heating outward-flow main pipe  308 . That is, the first branch pipe  301  communicates with the cooling outward-flow main pipe  307  or the heating outward-flow main pipe  308  selectively switched by the heat medium flow direction switching device  22 . The second branch pipe  302  corresponds to the third pipeline that selectively communicates with the cooling return-flow main pipe  305  or the heating return-flow main pipe  306 . That is, the second branch pipe  302  communicates with the cooling return-flow main pipe  305  or the heating return-flow main pipe  306  selectively switched by the heat medium flow direction switching device  23 . 
     As described above, in each valve block, the heat medium flow direction switching device  22 , the heat medium flow direction switching device  23 , and the heat medium flow control device  24  are disposed. The heat medium flow direction switching device  22  is constituted by a valve body rotating means  310 , a valve body  304   a , and a valve rod  313  that connects them. The valve body rotating means  310  is to rotate the valve body  304   a  around a rotary shaft, not shown. The rotation of the valve body rotating means  310  is transmitted to the valve body  304   a  via the valve rod  313 . 
     The heat medium flow direction switching device  23  is constituted by a valve body rotating means  309 , a valve body  304   b , and a valve rod  312  that connects them. The valve body rotating means  309  is to rotate the valve body  304   b  around a rotary shaft, not shown. The rotation of the valve body rotating means  309  is transferred to the valve body  304   b  via the valve rod  312 . The heat medium flow control device  24  is constituted by a valve body rotating means  311 , a valve body  303 , and a valve rod  314  that connects them. The valve body rotating means  311  is to rotate the valve body  303  around a rotary shaft, not shown. The rotation of the valve body rotating means  311  is transferred to the valve body  303  via the valve rod  314 . 
     As the valve body rotating means  309 , the valve body rotating means  310 , and the valve body rotating means  311 , they can be driven by using a stepping motor and giving a pulse signal by control means, not shown, for example. Instead of the stepping motor, the valve body rotating means  309 , the valve body rotating means  310 , and the valve body rotating means  311  may be constituted by other motors such as a geared motor or the like. Also, the valve body  304   a  and the valve body  304   b  will be described in detail in  FIG. 6  and the valve body  303  in  FIG. 7 , respectively. 
     The valve body  304   a , which is the sending side of the heat medium flow direction switching device  22 , is disposed in a connection portion between the first branch pipe  301  and the cooling outward-flow main pipe  307  as well as the heating outward-flow main pipe  308 . Similarly, the valve body  304   b , which is the sending side of the heat medium flow direction switching device  23 , is disposed in a connection portion between the second branch pipe  302  and the cooling return-flow main pipe  305  or the heating return-flow main pipe  306 . That is, the valve body  304   a  and the valve body  304   b  is rotated so as to communicate with the cooling-main pipe (a broken line arrow shown in  FIG. 5 ) or the heating-main pipe (a solid line arrow shown in  FIG. 5 ) and to switch between the cooling and the heating. If the valve body  303  of the heat medium flow control device  24  is rotated, an opening area is changed, and a flow rate of the heat medium to be sent into the indoor unit  2  can be adjusted. 
       FIG. 6  is an explanatory diagram for explaining the valve body  304  (the valve body  304   a  and the valve body  304   b ). On the basis of  FIG. 6 , the valve body  304  will be described in detail.  FIG. 6   a  is a perspective view of the valve body  304 ,  FIG. 6   b  is a plan view of the valve body  304 ,  FIG. 6   c  is a front view of the valve body  304  (side view seen from the side of an opening portion formed surface),  FIG. 6   d  is a left sectional view of the valve body  304 , and  FIG. 6   e  is a bottom view of the valve body  304 , respectively. In  FIG. 6 , the valve rod  312  is also illustrated (the same applies to the valve rod  313 ). In  FIG. 6 , the longitudinal direction of the valve body  304  is illustrated vertically, but in actuality, the valve body  304  is arranged so that the longitudinal direction thereof is laid horizontally, as shown in  FIG. 5 . 
     The valve body  304  is formed in a columnar shape. In this valve body  304 , an opening portion  304   aa  having an oval shape (a shape when the opening portion  304   aa  is seen on a front view) is formed. When this opening portion  304   aa  is seen on a side view, it has a tapered shape whose diameter is reduced toward the center axis direction of the valve body  304 . The inside of the valve body  304  at a position where the opening portion  304   aa  is formed is hollow, and a channel  304   ab  communicating with the opening portion  304   aa  is formed. 
     That is, in a state in which the opening portion  304   aa  of the valve body  304   a  is oriented downward (lower side in the state arranged as in  FIG. 5 ), the first branch pipe  301  communicates with the cooling outward-flow main pipe  307 . In a state in which the opening portion  304   aa  is oriented to the cooling outward-flow main pipe  307  side, the heat medium passes through the opening portion  304   aa , passes through the inside of the valve body  304   a , passes through the channel  304   ab  and is fed into the indoor unit  2  (a broken-line arrow shown in  FIG. 5 ). On the other hand, in a state in which the opening portion  304   aa  of the valve body  304   a  is oriented upward (upper side in the state arranged as in  FIG. 5 ), the first branch pipe  301  communicates with the heating outward-flow main pipe  308 . In a state in which the opening portion  304   aa  is oriented to the heating outward-flow main pipe  308  side, the heat medium passes through the opening portion  304   aa , passes through the inside of the valve body  304   a , passes through the channel  304   ab  and is fed into the indoor unit  2  (a solid-line arrow shown in  FIG. 5 ). 
     Similarly, in a state in which an opening portion  304   aa  of the valve body  304   b  is oriented downward (lower side in the state arranged as in  FIG. 5 ), the second branch pipe  302  communicates with the cooling return-flow main pipe  305 . In a state in which the opening portion  304   aa  is oriented to the cooling return-flow main pipe  305  side, the heat medium passes through the channel  304   ab , passes through the inside of the valve body  304   b , passes through the opening portion  304   aa  and flows into the cooling return-flow main pipe  305  (a broken-line arrow shown in  FIG. 5 ). On the other hand, in a state in which an opening portion  304   aa  of the valve body  304   b  is oriented upward (upper side in the state arranged as in  FIG. 5 ), the second branch pipe  302  communicates with the heating return-flow main pipe  306 . In a state in which the opening portion  304   aa  is oriented to the heating return-flow main pipe  306  side, the heat medium passes through the channel  304   ab , passes through the inside of the valve body  304   b , passes through the opening portion  304   aa  and flows into the heating return-flow main pipe  306  (a broken-line arrow shown in  FIG. 5 ). 
       FIG. 7  is an explanatory diagram for explaining the valve body  303 .  FIG. 8  is an outline diagram illustrating a rotating state of the valve body  303 . On the basis of  FIGS. 7 and 8 , the valve body  303  will be described in detail.  FIG. 7   a  is a perspective view of the valve body  303 ,  FIG. 7   b  is a plan view of the valve body  303 ,  FIG. 7   c  is a front view of the valve body  303  (side view seen from the side of an opening portion formed surface),  FIG. 7   d  is left sectional view of the valve body  303 , and  FIG. 7   e  is a bottom view of the valve body  303 . In  FIG. 7 , the valve rod  314  is also illustrated. In  FIG. 7 , the longitudinal direction of the valve body  303  is illustrated vertically, but in actuality, the valve body  303  is arranged so that the longitudinal direction thereof is laid horizontally, as shown in  FIG. 5 . 
     The valve body  303  is a valve body of the heat medium flow control device  24  that adjusts the flow rate of the heat medium flowing into the indoor unit  2 . This valve body  303  is constituted similarly to the valve body  304  described in  FIG. 6 . That is, the valve body  303  is formed in a columnar shape, an opening portion  303   a  having an oval shape (a shape when the opening portion  303   a  is seen on a front view) is formed, the inside of the valve body  303  at a position where the opening portion  303   a  is formed is hollow, and a channel  303   b  communicating with the opening portion  303   a  is formed. 
     An operation of the heat medium flow control device  24  will be described in brief. On the basis of the information obtained from the third heat medium temperature detecting means  33  and the fourth heat medium temperature detecting means  34 , the controller, not shown, calculates a required opening degree and transmits a required pulse number to the valve body rotating means  311 . The valve body rotating means  311  rotates only by the received required pulse number and rotates the valve body  303 . As shown in  FIG. 8 , by the rotation of the valve body  303 , the opening area of the opening portion  303   a  can be adjusted, and as a result, the flow rate of the heat medium can be adjusted. That is, by adjusting the opening area of the opening portion  303   a  (a full-open state in  FIG. 8A , a half-open state in  FIG. 8B  or an opening degree smaller than the half-open in  FIG. 8C  or the like), the flow rate of the heat medium flowing through the first branch pipe  301  can be variably adjusted. 
     As described above, the cooling outward-flow main pipe  307  and the heating return-flow main pipe  306  are arranged at adjacent positions (positions adjacent horizontally (in the right and left direction) at the substantially same height). Thus, the height of the valve block  350  (the length in the vertical direction in the state arranged as in  FIG. 5 ) can be lowered. Also, since the cooling outward-flow main pipe  307 , the heating outward-flow main pipe  308 , the cooling return-flow main pipe  305 , and the heating return-flow main pipe  306  are incorporated in the one valve block  350 , the valve block  350  can be made compact as compared with the device in which the main pipes are provided separately. 
     In the case of the cooling-only operation or the heating-only operation, the full amount of the heat medium flows through the cooling outward-flow main pipe  307 , the heating outward-flow main pipe  308 , the cooling return-flow main pipe  305 , and the heating return-flow main pipe  306 , and the diameter of the main pipe (pipeline  5 ) constituted by them needs to be made larger. For example, in the cooling-only operation or the heating-only operation if water is used for the heat medium in the capacity of approximately 10 horse power, water at the rate of 85 liters/min. flows. If water is used as the medium, from the view point of prevention of inlet attack, the flow velocity is kept to 2.0 [m/s] or less. By setting the thickness of the pipeline to 1.0 [mm], a pipeline having a pipeline diameter of approximately 32 [mm] needs to be selected. If such a thick pipeline is to be bent or worked, there are many restrictions such that the bending R cannot be made small and a considerable space is required, and thus, the device becomes considerably large. On the other hand, in the valve block  350  according to this embodiment, four main pipeline constituting portions and the valve body  304  are disposed in the one valve block  350 , and the plurality of valve blocks  350  are connected so that the cooling outward-flow main pipe  307 , the heating outward-flow main pipe  308 , the cooling return-flow main pipe  305 , and the heating return-flow main pipe  306  are automatically formed, the pipelines around the valve are simplified, and drastic size reduction can be realized. Also, in order to facilitate connection of the valve block  350 , the connection portions are formed in the male and female shapes, and a seal is formed by an O-ring. As a result, manufacturing time is drastically reduced, and productivity is improved. 
     Also, by installing the valve body  303 , the valve body  304   a , and the valve body  304   b  such that the longitudinal directions thereof are not vertical (perpendicular direction) but horizontal, the first branch pipe  301  and the second branch pipe  302  to the indoor unit  2  can be also made lateral pipelines, and the height of the valve block  350  (the length in the vertical direction in the state arranged as in  FIG. 5 ) can be further reduced. Moreover, by installing the valve body rotating means  309 , the valve body rotating means  310 , and the valve body rotating means  311  horizontally, the thickness of the valve block  350  can be drastically reduced (reduction in the length in the vertical direction in the state arranged as in  FIG. 5 ). Since the relay unit  3  on which the valve block unit  300  is mounted is contained in a small place such as in the attic in many cases, the reduction in the height direction, that is, making a thinner structure is an important factor. 
       FIGS. 9 and 10  are explanatory diagrams for explaining connection of the valve block  350 . On the basis of  FIGS. 9 and 10 , the connection of the valve block  350  will be described in detail.  FIG. 9   a  shows a side view of the valve block  350  and  FIG. 9   b  shows a B-B sectional view of  FIG. 9   a  in a state in which the valve block  350  is to be connected, respectively. Also,  FIG. 10  shows a perspective view of a state in which the valve block  350  is to be connected. As described above, one end of each main pipe (the cooling outward-flow main pipe  307 , the heating outward-flow main pipe  308 , the cooling return-flow main pipe  305 , and the heating return-flow main pipe  306 ) is formed in the female shape and the other end in the male shape capable of being connected to the female-shaped end. 
     The end portion of the heating outward-flow main pipe  308  on the side face A side (left side in the figure) of the valve block  350  is a male-shaped connection portion. Around the end portion of this heating outward-flow main pipe  308 , seal means  316  is mounted so that the valve block can be connected to another valve block  350 . Also, the end portion of the cooling outward-flow main pipe  307  on the side face B side (right side in the figure) of the valve block  350  is a female-shaped connection portion. As the seal means  316 , an O-ring or the like is preferably used. Also, other seal materials such as flat packing may be used for the seal means  316 . 
     By employing the above structure, as shown in  FIGS. 9 and 10 , the plurality of valve blocks  350  can be connected easily, and the number of branches can be flexibly changed. Also, since the valve blocks  350  are constructed so as to be easily connected, workability (productivity) of the valve block  350  is also improved, and cost reduction can be realized. In  FIGS. 9 and 10 , the cooling outward-flow main pipe  307  and the heating outward-flow main pipe  308  are described as an example, but the same applies to the cooling return-flow main pipe  305  and the heating return-flow main pipe  306 . 
     If the distance between the pipelines  5  on the cooling side (cooling outward-flow main pipe  307  and the cooling return-flow main pipe  305 ) and the pipelines  5  on the heating side (heating outward-flow main pipe  308  and the heating return-flow main pipe  306 ) is short, thermal interference might occur. If thermal interference occurs, the temperature of the heat medium flowing through the pipeline  5  on the cooling side is raised, and to the contrary, the temperature of the heat medium flowing through the pipeline  5  on the heating side is lowered, which might lead to performance deterioration. Thus, it is important to examine the distance between the pipeline  5  on the cooling side and the pipeline  5  on the heating side and the temperature change caused by that (See  FIG. 13 ). 
       FIG. 11   a  is a graph illustrating an example of a relationship between the pipeline distance and the temperature rise. On the basis of  FIG. 11   a , the relationship of the distance between the pipeline  5  on the cooling side and the pipeline  5  on the heating side to the temperature change caused by that will be described. In  FIG. 11   a , the horizontal axis indicates the pipeline distance [m] and the vertical axis indicates the temperature rise [° C.], respectively. In  FIG. 11   a , a calculation result is shown as an example, assuming that the temperature of hot water (the temperature of the heat medium flowing through the main pipe on the heating side) is 45° C., the temperature of cold water (the temperature of the heat medium flowing through the main pipe on the cooling side) is 10° C., the pipeline material is polybutene, and the heat conductivity is 0.20 (W/mK). The pipeline diameter is 38 [mm] and the contact distance is 1 [mm]. 
     From  FIG. 11   a , it is known that the temperature change is saturated when the distance is approximately 15 mm (1.5 cm). From this result, it is known that the thermal interference can be suppressed by ensuring 15 mm or more for the distance between the main pipe on the cooling side and the main pipe on the heating side. Since the heat conductivity is different depending on the pipeline material, the relationship between the temperature rise and the pipeline distance is preferably examined for each heat conductivity. Thus, the examination result when the brass is used for the body material is shown in  FIG. 11   b.    
     From  FIG. 11   a , it is known that if the pipeline material is brass, the temperature change is saturated when the distance is approximately 100 mm. From this result, it is known that the thermal interference can be suppressed by ensuring 100 mm or more for the distance between the main pipe on the cooling side and the main pipe on the heating side. By ensuring 100 [mm] or more for the distance between the main pipe on the cooling side and the main pipe on the heating side, the thermal interference can be prevented, but the valve body block becomes extremely large, and the merit of size reduction by the valve-block unit is reduced. That is, if the material with large heat conductivity such as brass, copper, iron, aluminum and the like is used as the body material of the valve block, the main pipe on the cooling side needs to be thermally shut off from the main pipe on the heating side. 
       FIG. 12  is an explanatory diagram for explaining another means that suppresses thermal interference if prevention of the thermal interference is difficult with the above-described distance. On the basis of  FIG. 12 , another means that suppresses thermal interference between the pipeline  5  on the cooling side and the pipeline  5  on the heating side will be described. In  FIG. 11   a  and  FIG. 11   b , the example in which the thermal interference is suppressed by the pipeline distance was described, but in  FIG. 12 , an example in which the thermal interference is suppressed by forming a slit  355  between the pipeline  5  on the cooling side and the pipeline  5  on the heating side so as to reduce an influence of heat conductivity is illustrated. As shown in  FIG. 12 , the thermal interference can be also suppressed by forming the slit  355 . The thermal interference may be suppressed both by the pipeline distance and the slit. 
     In order to reduce the size of the valve-block unit, an upper limit of the distance between the main pipe on the cooling side and the main pipe on the heating side is considered to be approximately 20 [mm], and the heat conductivity at that time is approximately 1.0 [W/mK].  FIG. 11   c  shows a relationship of the distance between the main pipe on the cooling side and the main pipe on the heating side to the temperature rise at 1.0 [W/mK]. As is known from  FIG. 11   c , it is saturated approximately around 20 [mm]. The heat conductivity of cross-linked polyethylene is approximately 0.4 [W/mK], and the distance between the cooling-main pipe and the heating-main pipe required for saturation of the temperature rise is approximately 15 mm. Also, the heat conductivity of PPS is approximately 0.22 [W/mK], and thermal interference can be prevented by ensuring the same distance (15 mm) as that for polybutene. 
     In Embodiment 1, the example in which a near-azeotropic refrigerant such as R410A and R404A and the like, a nonazeotropic refrigerant mixture such as R407c and the like, a refrigerant having a relatively small global warming potential such as CF 3 CF═CH 2  and the like including a double bond in the chemical formula or a mixture thereof or a natural refrigerant such as carbon dioxide, propane and the like can be used as the heat-source-side refrigerant as described above is described, but the refrigerant is not limited by those cited above. Also, in Embodiment 1, the example in which the accumulator  17  is disposed in the outdoor unit  1  is described, but without the accumulator  17 , the same operation is performed and the same advantages are exerted. 
     Also, in general, an air blowing device is disposed in the heat-source-side heat exchanger  12  and the use-side heat exchanger  26  so that condensation or evaporation is promoted by air-blowing in many cases, but that example is not limiting. For example, as the use-side heat exchanger  26 , a heat exchanger such as a panel heater using radiation can be used, and as the heat-source-side heat exchanger  12 , a heat exchanger of a water-cooling type in which heat is moved by water or anti-freezing fluid can be used, and any type of heat exchanger can be used as long as its structure is capable of heat radiation or heat absorption. 
     The example in which the heat medium flow direction switching device  22 , the heat medium c flow direction switching device  23 , and the heat medium flow control device  24  are disposed corresponding to each of the use-side heat exchangers  26  is described, but that example is not limiting. For example, a plurality of them may be connected to one unit of the use-side heat exchanger  26 . In this case, the heat medium flow direction switching device  22 , the heat medium flow direction switching device  23 , and the heat medium flow control device  24  connected to the same use-side heat exchanger  26  may be operated in the same way. Also, the example in which two units of the heat medium heat exchanger  15  are disposed is described, but naturally the number is not limiting, but three or more of them may be disposed as long as it is configured so that the heat medium can be cooled and/or heated. 
     Moreover, the example in which the third heat medium temperature detecting means  33  and the fourth heat medium temperature detecting means  34  are arranged inside the relay unit  3  is illustrated, but some of or all of them may be arranged inside the indoor unit  2 . If they are arranged in the relay unit  3 , the valves and pumps on the heat medium side and the like can be concentrated in the same housing, which leads to an advantage of easy maintenance. On the other hand, if they are arranged inside the indoor unit  2 , they can be handled easily as in the case of the expansion valve in a prior-art direct expansion type indoor unit, and since it is installed close to the use-side heat exchanger  26 , there is an advantage that it is not affected by heat loss of the extended pipeline and controllability of a heat load in the indoor unit  2  is good. Also, in a system to which a plurality of the indoor units  2  are connected, even if the heat medium flow control device  24  fails in one indoor unit  2 ,  22  can be replaced relatively easily without stopping the other indoor units  2 . 
     As described above, since the valve block unit  300  according to Embodiment 1 is constituted by connecting the plurality of valve blocks  350 , drastic size reduction can be realized. That is, the size reduction of the relay unit  3  on which the valve block unit  300  is mounted can be realized. Also, since the valve block  350  can be easily connected, assembling performance is improved, and labor or time required for installation can be reduced. Moreover, since the valve block unit  300  suppresses thermal interference of the pipelines  5 , performance deterioration can be reduced. Therefore, by using the valve block unit  300 , contribution can be made to energy saving. 
     Embodiment 2 
       FIG. 13  is a view illustrating an arrangement structure of the relay unit  3 . The relay unit  3  in  FIG. 13  has the valve block unit  300  formed by connecting 8 units of the valve blocks  350 , and the heat medium can be made to branch into 8 units of the indoor units  2 , respectively. By connecting the valve blocks  350  described in the above-described embodiment, the device and the pipeline that branch and merge the heat medium in each indoor unit  2  can be integrated and simplified, and moreover, by devising pipeline positions and the like, the relay unit  3  is thinned. Also, 8 units of the heat medium delivery devices  21  are provided. The 8 units of the heat medium delivery devices  21  are used in four each, respectively, for circulating the heat medium heated by the first heat medium heat exchanger  15   a  and the heat medium cooled by the second heat medium heat exchanger  15   b , for example. 
     Here, the relay unit  3  in  FIG. 13  has 8 units of the valve blocks  350  and 8 units of the heat medium delivery devices  21 , but the numbers are not limiting. Also, though not shown in  FIG. 13 , the devices, equipment and means provided in the relay unit  3  in  FIG. 1  and the like such as the gas-liquid separator  14 , the expansion device  16  and the like are assumed to be mounted. 
       FIG. 14  is a view illustrating the connection of the valve blocks  350 . As described above, the valve blocks  350  are connected so as to branch into the number of the indoor units  2 . Then, each main pipe is connected. Through holes in each main pipe on the both ends are capped with the caps  318  and  319  if it is not to be connected to the outside pipeline, for example. Also, after the valve block  350  is connected, each valve block  350  is fixed by screwing or the like to a connecting plate  500  so as to form the valve block unit  300 . As a result, each connected valve block  350  is contained in a housing  600  by preventing removal by a pressure of the heat medium passing through the main pipe and the like of the valve block unit  300 . 
       FIG. 15  is a diagram illustrating an outline of the structure of the housing  600  that contains the relay unit  3 . The housing  600  of the relay unit  3  is constituted by combining sheet metals  600   a  and  600   b . Here, the relay unit  3  is fixed to the sheet metal  600   a  and cannot be removed therefrom. On the other hand, the sheet metal  600   b  is usually screwed into the sheet metal  600   a  and can be slid in a direction of an arrow indicated in  FIG. 15  by removing the screw. Thus, by sliding and opening/closing the sheet metal  600   b  in the direction of the side face, the relay unit  3  in the housing  600  can be exposed. By forming the housing  600  in the structure that can be slidably opened/closed the sheet metal  600   b , even if the relay unit  3  is installed in a space small in the height direction such as in the attic, for example, the housing can be removed easily by sliding the sheet metal  600   b  in the direction other than the height direction. In  FIG. 15 , the front face, the upper face, and the right side face can be removed, and maintenance works such as component replacement, maintenance and the like of the relay unit  3  can be performed through these faces. The number of faces that can be slidably opened/closed is not particularly limited, here. 
     Also, the valve body rotating means  310 ,  309 , and  311  of the heat medium delivery device  21 , the heat medium flow direction switching devices  22  and  23 , and the heat medium flow control device  24  are concentrated so as to be oriented to one direction so that the means can be replaced through the side face of the housing  600  of the relay unit  3 . In the relay unit  3  of this embodiment, as shown in  FIG. 13  and the like, at least the valve body rotating means  311 ,  310 , and  309  and the actuator (driving device) of the heat medium delivery device  21  are concentrated so as to be oriented to the front, which is the direction in which the sheet metal  600   b  is slid. 
     Here, as shown in  FIGS. 4 and 5 , the valve body rotating means  311 ,  310 , and  309  are screwed into the side face of the valve block  350 . For example, if the valve body rotating means  311 ,  310  or  309  or the like fails and is subjected to repair or replacement of a component, a worker or the like, for example, can put the head and hands into the space in the attic and remove the screw and the valve body rotating means  311 ,  310  and  309  from the relay unit  3 . Also, mounting of the means and device relating to repair and component replacement on the relay unit  3  can be also performed in the same way. As described above, in the relay unit  3 , by concentrating the means which is likely to require maintenance such as an actuator on the one face side (one side face side in this embodiment), component replacement and the like can be facilitated, and maintenance performance can be drastically improved. 
       FIG. 16  is a diagram illustrating an arrangement relationship between the valve block unit  300  and the heat medium heat exchanger  15 . As described above, in the relay unit  3  in this embodiment, the valve blocks  350  are connected so as to form the valve block unit  300  so as to promote thinning. Here, as shown in  FIGS. 4   a ,  5  and the like, on the return side to which the heat medium flows from the indoor unit, the heat medium flow direction switching device  23  and the return main pipes  305  and  306  are disposed. Also, on the outgoing side from which the heat medium flows to the indoor unit  2 , the heat medium flow direction switching device  22  and the outgoing main pipes  307  and  308  are disposed. On the outgoing side, the heat medium flow control device  24  is further disposed. As described above, since the devices and pipelines are provided on the outgoing side and the return side, respectively, by generating a given distance between the first branch pipe  301  and the second branch pipe  302 , a space is created. 
     Though not particularly illustrated in the above-described embodiment, in this embodiment, the heat medium heat exchanger  15  is constituted by a planar heat exchanger such as a micro-channel heat exchanger or the like, for example. Here, the micro-channel heat exchanger is a heat exchanger having a porous flat pipe, for example, and can efficiently exchange heat since its heat transfer area per volume (heat transfer surface density) is large. 
     Then, the heat medium heat exchanger  15   a  is inserted into and arranged in a space generated between the first branch pipe  301  and the second branch pipe  302 . Also, the heat medium heat exchanger  15   b  is inserted into and arranged in a space generated at a lower part of the return branch pipe  302 . Thus, when seen from the side face, as shown in  FIG. 16 , the outgoing branch pipe  301 , the heat medium heat exchanger  15   a , the return branch pipe  302 , and the heat medium heat exchanger  15   b  are arranged in this order from the upper side. In the case of the above-described cooling-main operation, for example, the h heat medium heat exchanger  15   a  works as a condenser and heats the heat medium, while the heat medium heat exchanger  15   b  works as an evaporator and cools the heat medium. Thus, by overlapping the heat medium heat exchanger  15   a  and the heat medium heat exchanger  15   b  with each other, they thermally interfere with each other, which results in drastic performance deterioration. Thus, while overlapping of the heat medium heat exchanger  15   a  and the heat medium heat exchanger  15   b  is avoided, the space generated by the outgoing branch pipe  301  and the return branch pipe  302  is effectively used for arrangement. 
     Also, in  FIG. 16 , the heat medium heat exchanger  15   a  is arranged above the heat medium heat exchanger  15   b . Since the heat medium heat exchanger  15   b  works as an evaporator in the case of the cooling-main operation or the like, the temperature of the heat medium heat exchanger  15   b  becomes lower than the temperature of the ambient air and condensation might occur. The condensation water drops to the lower part of the relay unit  3  and is collected in a drain pan (not shown) and is emitted from the relay unit  3 , but since the heat medium heat exchanger  15   b  is located on the lower side, the condensation water does not drop to the other devices and the like. Also, if the heat medium heat exchanger  15   a  works as a condenser, since it warms the ambient air, rising air is generated but since the heat medium heat exchanger  15   a  is located above the heat medium heat exchanger  15   b , performance of the heat medium heat exchanger  15   b  as an evaporator is not lowered. From the above reasons, it is preferable that the heat medium heat exchanger  15   a  is installed on the upper side and the heat medium heat exchanger  15   b  on the lower side from the viewpoint of performances. 
     As described above, according to the relay unit  3  of Embodiment 2, by connecting the valve blocks  350  so as to form the valve block unit  300 , the devices and pipelines that branch the heat medium to each indoor unit  2  and merge it can be integrated and simplified, and by further devising the pipeline positions and the like, the relay unit  3  can be thinned. Also, since the heat medium heat exchanger  15 , which is a planar heat exchanger such as a micro-channel type heat exchanger or the like, is inserted into and arranged in the space generated by the outgoing branch pipe  301  and the return branch pipe  302 , an unnecessary space is not created in the housing  600  but the space can be effectively used, and thinning of the relay unit  3  can be further promoted. Thus, even if the relay unit  3  is installed in an environment with harsh restrictions to one direction (height direction in the case of a space in the attic) such as a space in the attic, the device and means of the relay unit  3  can be efficiently contained in the housing  600  by effectively use the space. And the capacity of the housing  600  can be reduced, and contribution can be further made to thinning of the relay unit  3 . 
     Also, by concentrating the means with high probability of maintenance such as an actuator on one of the faces of the relay unit  3 , the maintenance work such as component replacement can be performed easily, and maintenance performance can be drastically improved. At this time, since the sheet metal  600   b  is formed to be slid in the side-face direction so that the housing  600  can be opened/closed, opening/closing can be performed without being obstructed by the space small in the height direction, for example, and the merit of making a thinner structure can be enjoyed. 
     Embodiment 3 
       FIG. 17  is a diagram illustrating another example of an installed form of the relay unit  3 . In the above-described embodiment, the relay unit  3  is described to be installed so-called horizontally in a space with restrictions in the height direction such as a space in the attic, but the installation place of the relay unit  3  is not limited. For example, as shown in  FIG. 17 , if the heat medium inverter is to be installed in a room where few people come in and out, the relay unit may be installed vertically so as to become long in the height direction. The advantage of making a thinner structure can be also exerted in the vertical installation. 
     Here, in the case of vertical installation, since the relay unit is hidden in the wall in many cases, it has a structure that the sheet metal  600   c  can be taken out from the front side unlike the horizontal installation type. In the valve block unit  300 , the valve body rotating means  310 ,  309 , and  311  are oriented to the front shown in  FIG. 17  and arranged so that the valve body rotating means  310 ,  309 , and  311  can be replaced easily. Also, since the heat medium delivery device  21  cannot suck the heat medium by itself, the heat medium delivery device is installed close to the bottom part of the relay unit  3  so that the suction side of the heat medium delivery device  21  is naturally filled with the heat medium in the structure. The bottom face of the housing  600  should be constructed so that the heat medium can be temporarily held and the heat medium can be emitted in preparation for condensation water or accidental leakage of the heat medium. For that purpose, the bottom face has the same structure as that of the so-called drain pan. Also, in the case of the vertical installation, since it is used by being embedded in the wall in many cases, the branch pipes  301  and  302  to each indoor unit come out of the upper face, the side face, and the rear face in the structure. 
     Embodiment 4 
       FIG. 18  is a longitudinal sectional view illustrating a sectional configuration of a valve block  351  constituting a valve block unit  300   a  according to Embodiment 4 of the present invention in a simplified manner. On the basis of  FIG. 18 , the configuration of the valve block  351  will be described along with the flow of the heat medium. In Embodiment 2, a difference from Embodiment 1 will be mainly described, and the same reference numerals are given to the same components as those in Embodiment 1 and the description will be omitted. 
     In Embodiment 1, the heat medium flow direction switching device  22  and the heat medium flow direction switching device  23  switch channels by the separate valve bodies (the valve body  304   a  and the valve body  304   b ) and the separate valve body rotating means (valve body rotating means  309  and the valve body rotating means  310 ). By means of the functions of the heat medium flow direction switching device  22  and the heat medium flow direction switching device  23 , these operations are synchronized. That is, during the cooling, the heat medium flow direction switching device  22  directs the valve to the cooling direction and the heat medium flow direction switching device  23  also directs the valve to the cooling direction (See the broken-line arrow in  FIG. 5 ). Also, during the heating, the heat medium flow direction switching device  22  directs the valve to the heating direction and the heat medium flow direction switching device  23  also directs the valve to the heating direction (See the solid-line arrow in  FIG. 5 ). 
     Therefore, the heat medium flow direction switching device  22  and the heat medium flow direction switching device  23  can be handled by one valve body rotating means and one valve body. As shown in  FIG. 18 , the valve block  351  is configured so that the cooling outward-flow main pipe  307  and the cooling return flow main pipe  305  as well as the heating outward-flow main pipe  308  and the heating return-flow main pipe  306  are disposed horizontally side by side, respectively. Also, in the valve block, 351, the heat medium flow direction switching device  25  that functions similarly to the heat medium flow direction switching device  22  and the heat medium flow direction switching device  23  is disposed. That is, the heat medium flow direction switching device  25  shares the function of the heat medium flow direction switching device  22  and the heat medium flow direction switching device  23 . 
     That is, the heat medium flow direction switching device  25  selectively switches the cooling outward-flow main pipe  307  and the heating outward-flow main pipe  308  and also selectively switches the cooling return-flow main pipe  305  and the heating return-flow main pipe  306 . This heat medium flow direction switching device  25  is constituted by the valve body rotating means  405 , the valve body  407 , and the valve rod  409  that connects them. The valve body rotating means  405  is to rotate the valve body  407  around the rotary shaft, not shown. The rotation of the valve body rotating means  405  is transmitted to the valve body  407  via the valve rod  409 . In  FIG. 18 , the example in which the heat medium flow control device  24  is disposed in the valve block  351  is illustrated, but this heat medium flow control device  24  is not indispensable or may be disposed on the branch pipe  302  side. 
       FIG. 19  is an explanatory diagram for explaining the valve body  407 . On the basis of  FIG. 19 , the valve body  407  will be described in detail.  FIG. 19   a  is a perspective view of the valve body  407 ,  FIG. 19   b  is a plan view of the valve body  407 ,  FIG. 19   c  is a front view of the valve body  407  (side view seen from the side of an opening portion formed surface),  FIG. 19   d  is a left sectional view of the valve body  407 , and  FIG. 19   e  is a bottom view of the valve body  407 , respectively. In  FIG. 19 , the valve rod  409  is also illustrated. In  FIG. 19 , the longitudinal direction of the valve body  407  is illustrated vertically, but in actuality, the valve body  407  is arranged so that the longitudinal direction thereof is laid horizontally as shown in  FIG. 18 . 
     The valve body  407  is formed in an elongated columnar shape. In this valve body  407 , an opening portion  407   a  having a long hole shape (a shape when the opening portion  407   a  is seen on a front view) along the longitudinal direction of the valve body  407 , an opening portion  407   b  having an oval shape (a shape when the opening portion  407   b  is seen on a front view), and an opening portion  407   c  communicating with the opening portion  407   b  are formed. The opening portion  407   c  is formed in the bottom face of the valve body  407 . In order to have the opening portion  407   b  and the opening portion  407   c  communicate with each other, the inside of the valve body  407  is made hollow. 
     That is, in a state in which the opening portion  407   b  of the valve body  407  is oriented downward (lower side in the state arranged as in  FIG. 18 ), the first branch pipe  301  communicates with the cooling outward-flow main pipe  307  via the opening portion  407   c . In the state in which the opening portion  407   b  is oriented to the cooling outward-flow main pipe  307  side, the heat medium passes through the opening portion  407   b  and the opening portion  407   c , and the heat medium is fed into the indoor unit  2  (the broken-line arrow in  FIG. 18 ). On the other hand, in a state in which the opening portion  407   b  of the valve body  407  is oriented upward (upper side in the state arranged as in  FIG. 18 ), the first branch pipe  301  communicates with the heating outward-flow main pipe  308  via the opening portion  407   c . In the state in which the opening portion  407   b  is oriented to the heating outward-flow main pipe  308  side, the heat medium passes through the opening portion  407   b  and the opening portion  407   c , and the heat medium is fed into the indoor unit  2  (the broken-line arrow in  FIG. 18 ). 
     Similarly, in a state in which the opening portion  407   a  of the valve body  407  is oriented downward (lower side in the state arranged as in  FIG. 18 ), the second branch pipe  302  communicates with the cooling return-flow main pipe  305 . In the state in which the opening portion  407   a  is oriented to the cooling return-flow main pipe  305  side, the heat medium from the first branch pipe  301  flows into the cooling return-flow main pipe  305  through the opening portion  407   a  (the broken-line arrow shown in  FIG. 18 ). On the other hand, in a state in which the opening portion  407   a  of the valve body  407  is oriented upward (upper side in the state arranged as in  FIG. 18 ), the second branch pipe  302  communicates with the heating return-flow main pipe  306 . In the state in which the opening portion  407   a  is oriented to the heating return-flow main pipe  306  side, the heat medium from the first branch pipe  301  flows into the heating return-flow main pipe  306  through the opening portion  407   a  (the broken-line arrow shown in  FIG. 18 ). 
     By employing the above structure, the number of installed valve body rotating means can be reduced from 2 to 1. Thus, a cost can be reduced for the reduction. Also, since the heat medium flow direction switching devices are shared in each set, further size reduction is realized. Also, since the number of valve body rotating means is reduced, power consumption (current value) can be also reduced. 
       FIG. 20  is a perspective view illustrating the structure of the valve block unit  300   a  in detail.  FIGS. 21 and 22  are explanatory diagrams for explaining the connection of the valve block  351 . On the basis of  FIGS. 20 to 22 , the valve block  351  will be described in detail.  FIG. 21   a  is a side view of the valve block  351 , and  FIG. 21   b  is a C-C sectional view of  FIG. 21   a  in a state in which the valve block  351  is to be connected, respectively. Also,  FIG. 22  is a perspective view illustrating a state in which the valve block  351  is to be connected. 
     The valve block unit  300   a  shown in  FIG. 20  is constituted by connecting the four valve blocks  351  (the valve block  351   a  to the valve block  351   d ) and connected to four indoor units  2  similarly to the valve block unit  300  according to Embodiment 1. The valve block  351  has the heat medium flow direction switching device  22 , the heat medium flow direction switching device  23 , and the heat medium flow control device  24 , which cover one branch altogether. That is, the valve block unit  300   a  according to Embodiment 2 branches into four parts. 
     The cooling outward-flow main pipe  307  (illustrated as the cooling outward-flow main pipe  307   a , the cooling outward-flow main pipe  307   b , and the cooling outward-flow main pipe  307   c  from the right side in the figure), the heating outward-flow main pipe  308  (illustrated as the heating outward-flow main pipe  308   a , the heating outward-flow main pipe  308   b , and the heating outward-flow main pipe  308   c  from the right side in the figure), the cooling return-flow main pipe  305  (illustrated as the cooling return-flow main pipe  305   a , the cooling return-flow main pipe  305   b , and the cooling return-flow main pipe  305   c  from the right side in the figure), and the heating return-flow main pipe  306  (illustrated as the heating return-flow main pipe  306   a , the heating return-flow main pipe  306   b , and the heating return-flow main pipe  306   c  from the right side in the figure) of each valve block  351  are connected, respectively, and form the main pipe (pipeline  5 ). It is needless to say that the valve block  351   d  on the left side in the figure also has each main pipe. 
     One end of each main pipe (the cooling outward-flow main pipe  307 , the heating outward-flow main pipe  308 , the cooling return-flow main pipe  305 , and the heating return-flow main pipe  306 ) is formed into a female shape and the other end is formed into a male shape capable of connecting to the female-shaped end so that the valve blocks  351  can be connected. And on the cooling outward-flow main pipe  307   a  and the heating outward-flow main pipe  308   a  of the valve block  351   a  located at one of the both ends of the valve block unit  300   a , the caps  318  that cap them are disposed. On the other hand, on the cooling return-flow main pipe  305   d  and the heating return-flow main pipe  306   d  of the valve block  351   d  located at the other of the both ends of the valve block unit  300   a , the caps  319  that cap them are disposed. The heating return-flow main pipe  306   a  is connected to the suction side of the heating-side pump (first heat medium delivery device  21   a ), and the cooling return main pump  305   a  is connected to the suction side of the cooling-side pump (second heat medium delivery device  21   b ), respectively. 
     By employing the above structure, as shown in  FIGS. 21 and 22 , the plurality of valve blocks  351  can be connected easily, and the number of branches can be flexibly changed. Also, since the valve blocks  350  are constructed so as to be easily connected, workability (productivity) of the valve block  350  is also improved, and cost reduction can be realized. In  FIGS. 21 and 22 , the cooling outward-flow main pipe  307  and the heating outward-flow main pipe  308  are described as an example, but the same applies to the cooling return-flow main pipe  305  and the heating return-flow main pipe  306 . 
     The valve block unit  300   a  is capable of switching the heat medium channel and also forms each main pipe by connecting the plurality of valve blocks  351 . According to this valve block unit  300   a , as compared with the device in which the channel switching device and the pipeline are provided separately, the pipeline around the valve can be simplified. Therefore, the unit on which the valve block unit  300   a  is mounted (the relay unit  3  similar to Embodiment 1) can be made compact. 
     A hole  411  shown in  FIG. 22  is a sacrificed hole required for forming a channel of the valve block  351  and is capped with a lid  410 . If the hole  411  is not capped, the return pipeline of each valve block  351  is connected, and thus, the pipeline is capped with the lid  410 . On the lid  410 , two seal means  410   a  are disposed. Here, an example in which the seal means  410   a  is an O-ring is illustrated. It is also known from  FIG. 21  that the seal means  410   a  is disposed on the lid  410  and shuts off the return pipeline for each valve block  351 . 
     As described above, since the valve block unit  300   a  according to Embodiment 2 is constituted by connecting the plurality of valve blocks  351 , drastic size reduction can be realized. That is, the size reduction of the relay unit  3  on which the valve block unit  300   a  is mounted can be realized. Also, since the valve block  351  can be easily connected, assembling performance is improved, and labor or time required for installation can be reduced. Moreover, since the valve block unit  300   a  suppresses thermal interference of the pipelines  5 , performance deterioration can be reduced. Therefore, by using the valve block unit  300   a , contribution can be made to energy saving. 
     If leakage of the valve block  351  is to be inspected, in a state of the valve block unit  300  in which the plurality of valve blocks  350  are connected as shown in  FIGS. 4 and 20 , a pressure of approximately 3 kgf/cm 2  is applied by using nitrogen, helium or the like so as to check if there is any leakage from the seal means  316  and  410   a  and then, the valve block unit is shipped. It is needless to say that the main pipes  308  and  307 , the branch pipes  301  and  302  in  FIG. 20 , and the main pipes  305  and  306  in  FIG. 4  are capped so that they can be pressurized. By conducting a leakage test in the above valve block unit  300  state, inspection time can be reduced, and productivity can be improved. Also, by conducting an inspection in the number of branches actually used in the product, the quality can be made stable, production time can be reduced, and cost can be reduced. That is because if the leakage test is conducted for each valve block  350 , for example, the leakage test is needed even after they are assembled into the valve block unit  300 , which means that the leakage test is conducted twice, which is wasteful. 
     Embodiment 5 
     In the above-described embodiments, the example in which the valve block unit  300  is mounted on the relay unit  3  is described, but a device in which the valve block unit  300  is used is not limited to the relay unit  3 . For example, the valve block unit  300  can be also used for the other three-way valves and flow controllers in the air conditioning apparatus. Also, the fluid to be passed through the valve block unit  300  is not limited to water and the like, and other fluids such as a refrigerant can be made to pass. 
     Here, if the valve block unit  300  is applied to a refrigerant used in an air conditioning apparatus in general, since it is difficult to apply a plastic material to the body of the valve block  350  from the viewpoint of a design pressure, brass, aluminum or the like is used. Also, if the type of the medium is changed, considering swelling or deterioration, the seal means  316  and the like need to be selected so as to be suitable for the fluid. It is needless to say that the body material of the valve block  350  needs to be selected considering corrosion or the like. 
     Also, in the above-described embodiments, the example in which the heat medium heated in the heat medium heat exchanger  15   a  is passed through the main pipes  306  and  308 , while the heat medium cooled in the heat medium heat exchanger  15   b  is passed through the main pipes  305  and  307  is described, but that example is not limiting. There can be various forms such that the heat media at different temperatures according to cooling (heating) are made to pass through the both main pipes and the like. Also, as for the above-described valve block unit  300 , not only in the air conditioning apparatus, but usual water (cold water) is made to pass through the cooling outward-flow main pipe  307  and hot water from a boiler is made to pass through the heating outward-flow main pipe  308 , for example, the position of the valve body  304   a  of the heat medium flow direction switching device  22  is adjusted, and hot water and cold water are mixed. As a result, the temperature of the hot water coming out of the branch pipe  301  can be freely controlled and can be also used for creating hot water for bath or shower. 
     REFERENCE SIGNS LIST 
       1  outdoor unit,  2  indoor unit,  2   a  indoor unit,  2   b  indoor unit,  2   c  indoor unit,  2   d  indoor unit,  3  relay unit,  4  refrigerant pipeline,  4   a  connection pipeline,  4   b , connection pipeline,  5  pipeline,  5   a , pipeline,  5   b  pipeline,  10  compressor,  11  four-way valve,  12  heat-source-side heat exchanger,  13   a  check valve,  13   b  check valve,  13   c  check valve,  13   d  check valve,  14  gas-liquid separator,  15  heat medium heat exchanger,  15   a  first heat medium heat exchanger,  15   b  second heat medium heat exchanger,  16  expansion device,  16   a  expansion device,  16   b  expansion device,  16   c  expansion device,  16   d  expansion device,  16   e  expansion device,  17  accumulator,  21  heat medium delivery device,  21   a  first heat medium delivery device,  21   b  second heat medium delivery device,  22  heat medium flow direction switching device,  22   a  heat medium flow direction switching device,  22   b  heat medium flow direction switching device,  22   c  heat medium flow direction switching device,  22   d  heat medium flow direction switching device,  23  heat medium flow direction switching device,  23   a  heat medium flow direction switching device,  23   b  heat medium flow direction switching device,  23   c  heat medium flow direction switching device,  23   d  heat medium flow direction switching device,  24  heat medium flow control device,  24   a  heat medium flow control device,  24   b  heat medium flow control device,  24   c  heat medium flow control device,  24   d  heat medium flow control device,  25  heat medium flow direction switching device,  26  use-side heat exchanger,  26   a  use-side heat exchanger,  26   b  use-side heat exchanger,  26   c  use-side heat exchanger,  26   d  use-side heat exchanger,  31  first heat medium temperature detecting means,  31   a  first heat medium temperature detecting means,  31   b  first heat medium temperature detecting means, 32 second heat medium temperature detecting means,  32   a  second heat medium temperature detecting means,  32   b  second heat medium temperature detecting means,  33  third heat medium temperature detecting means,  33   a  third heat medium temperature detecting means,  33   b  third heat medium temperature detecting means,  33   c  third heat medium temperature detecting means,  33   d  third heat medium temperature detecting means,  34  fourth heat medium temperature detecting means,  34   a  fourth heat medium temperature detecting means,  34   b  fourth heat medium temperature detecting means,  34   c  fourth heat medium temperature detecting means,  34   d  fourth heat medium temperature detecting means,  35  first refrigerant temperature detecting means,  36  refrigerant pressure detecting means, 37 second refrigerant temperature detecting means,  38  third refrigerant temperature detecting means,  100  air conditioning apparatus,  300  valve block unit,  300   a  valve block unit,  301  first branch pipe, 302 second branch pipe,  303  valve body,  303   a  opening portion,  303   b  channel,  304  valve body,  304   a  valve body,  304   aa  opening portion,  304   ab  channel,  304   b  valve body,  305  cooling return-flow main pipe,  305   a  cooling return-flow main pipe,  305   b  cooling return-flow main pipe,  305   c  cooling return-flow main pipe,  305   d  cooling return-flow main pipe,  306  heating return-flow main pipe,  306   a  heating return-flow main pipe,  306   b  heating return-flow main pipe,  306   c  heating return-flow main pipe,  306   d  heating return-flow main pipe,  307  cooling outward-flow main pipe,  307   a  cooling outward-flow main pipe,  307   b  cooling outward-flow main pipe,  307   c  cooling outward-flow main pipe,  307   d  cooling outward-flow main pipe,  308  heating outward-flow main pipe,  308   a  heating outward-flow main pipe,  308   b  heating outward-flow main pipe,  308   c  heating outward-flow main pipe,  308   d  heating outward-flow main pipe,  309  valve body rotating means,  310  valve body rotating means,  311  valve body rotating means,  312  valve rod,  314  valve rod  316  seal means,  318  cap,  319  cap,  320  joint,  321  sacrificed hole,  350  valve block,  350   a  valve black,  350   b  valve block,  350   c  valve block,  350   d  valve block,  351  valve block,  351   a  valve block,  351   b  valve block,  351   c  valve block,  351   d  valve block,  355  slit,  405  valve body rotating means,  407  valve body,  407   a  opening portion,  407   b  opening portion,  407   c  opening portion,  409  valve rod,  410  lid,  410   a  seal means,  411  hole,  500  connecting plate,  600  housing,  600   a ,  600   b ,  600   c  sheet metal.