Patent Publication Number: US-6216484-B1

Title: Air flow switching type air conditioner for both cooling and heating

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to an air flow switching type air conditioner for both cooling and heating, and more particularly to an air conditioner for both cooling and heating which allows an efficient function of cooling and heating by optionally switching the indoor and outdoor air to flow either through an evaporator or through a condenser, and which can also serve as thermo-hygrostat. 
     2. Description of the Related Art 
     The conventional air conditioner for purpose of both cooling and heating had a construction equipped with both a cooling refrigeration cycle and a heater. Alternative type of air conditioner for both cooling and heating was constructed as a heat pump which has a heat exchanger at indoor side and another heat exchanger at outdoor side and directional valve for switching the flow of refrigerant. At cooling mode, the indoor heat exchanger functions as an evaporator to absorb heat from the room, and at heating mode, the indoor heat exchanger functions as a condenser to deliver heat into room. However, those conventional air conditioners for both cooling and heating were relatively complicated in structure and the cooling or heating efficiency was low, causing manufacturing and maintenance cost to increase. 
     SUMMARY OF THE INVENTION 
     The present invention, which is intended to resolve the drawbacks of the conventional air conditioners as described above, has the purpose of providing an air conditioner for both cooling and heating with novel structure, which can perform the function of cooling and heating by simply switching the direction of the air flow in and out of a room on a conventional cooling refrigeration cycle. 
     Furthermore, the present invention is intended to provide an air conditioner for not only cooling but also heating which can recover energy contained in the exhaust air during the indoor air ventilation and which can also precisely control or maintain the temperature and humidity in the room. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows a perspective view of a preferred embodiment according to the present invention with its part sectioned, 
     FIGS. 2 and 3 show diagrams for operating states at cooling mode and heating mode respectively and, 
     FIGS. 4 and 5 show conceptional view of another embodiment according to the present invention as used as a thermo-hygrostat. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     According to the present invention, there is provided an air flow switching type air conditioner for both cooling and heating having a compressor  4 , condenser  3 , an expansion valve  5  or capillary tube, an evaporator  2  and a refrigerant pipe  9  connecting those parts, as well as an air blower  10 , said air conditioner specifically including a case  1  which is so constructed that an indoor side discharge port  11  and an indoor side intake port  12 , both parts being open to the inside of a room, as well as an outdoor side discharge port  13  and an outdoor side intake port  14 , both parts being open to the outside, are separately partitioned by partition walls  25 , 26 , a heat exchange chamber  20  which is formed between said indoor side discharge port  11  and indoor side intake port  12  and between said outdoor side discharge port  13  and outdoor side intake port  14  and in which said evaporator and said condenser are each disposed in a partitioned space, a first damper  31  provided between said evaporator  2  and said indoor side discharge port  11 , a second damper  32  provided between said condenser  3  and said indoor side discharge port  11 , a third damper  33  provided between said indoor side intake port  12  and said evaporator  2 , a forth damper  34  provided between said indoor side intake port  12  and said condenser  3 , a fifth damper  35  provided between said outdoor side discharge port  13  and said evaporator  2 , a sixth damper  36  provided between said condenser  3  and said outdoor side discharge port  13 , a seventh damper  37  provided between said outdoor side intake port  14  and said evaporator  2  and a eighth damper  38  provided between said outdoor side intake port  14  and said condenser  3 , and wherein there is further included a controller by which the opening of said dampers is individually controlled. 
     According to another feature of the present invention, said heat exchange chamber  20  is partitioned into upper and lower heat exchange chambers  22 , 23  by a horizontal partition plate  21 , so that the evaporator  2  is arranged in said upper heat exchange chamber  22  and the condenser  3  is arranged in said lower heat exchange chamber  23 , whereby condensing water produced in said evaporator  2  should flow down to said condenser  3 . 
     According to a further feature of the invention, a humidity sensor  7  is provided at a predetermined position in the interior of a room R, and a reheater  6  for emitting condensing heat is connected between said condenser  3  and an expansion valve  5  or capillary tube, and wherein said reheater  6  is positioned between said evaporator  2  and said indoor air discharge port  11  to heat the air discharging into the inside of the room. 
     A preferred embodiment of the present invention is explained below in connection with the attached drawings. FIG. 1 shows the perspective view of a preferred embodiment of the invention which is partly sectioned and FIGS. 2 and 3 each show the operating state at cooling and heating mode. As can be seen, an indoor side discharge port  11  and an indoor side intake port  12  are formed opposite to the set of an outdoor side discharge port  13  and an outdoor side intake port  14  in a case  1 . The indoor side discharge port  11  and the outdoor side discharge port  13  are separated by a partition wall  25 , while the indoor side intake port  12  and the outdoor side intake port  14  are separated by a partition wall  26 . Between the discharge ports  11 , 13  and the intake ports  12 , 14  there is formed a heat exchange chamber  20 , which is bounded by the respective dampers  31 - 38 . The heat exchanger room  20  in turn is divided by the horizontally disposed partition plate  21  into the upper heat exchange chamber  22  for receiving the evaporator  2  and the lower heat exchange chamber  23  for receiving a condenser  3 . Condensing water produced on the evaporator  2  in the upper heat exchange chamber  22  falls to the condenser  3  in the lower heat exchange chamber  23  via appropriate drains formed on the partition plate  21  to thereby increase the heat efficiency of condenser  3 . 
     Referring to the dampers mentioned above, they are in the form of blinds or blades to regulate the opening for air flow in accordance with the control of a controller(not shown). The first damper  31  is disposed between the evaporator  2  and the indoor side discharge port  11  and so constructed as to regulate the flow rate of the air between them. Similarly a second damper  32  is disposed between the condenser  3  and the indoor side discharge port  11 . And, the third damper  33  is disposed between the indoor side intake port  12  and the evaporator  2 , the forth damper  34  between the indoor side intake port  12  and the condenser  3 , the fifth damper  35  between the outdoor side intake port  14  and the evaporator  2 , the sixth damper  36  between the outdoor side intake port  14  and the condenser  3 , the seventh damper  37  between the outdoor side discharge port  13  and the evaporator  2 , and the eight damper  38  between the outdoor side discharge port  13  and the condenser  3 . 
     In the indoor side discharge port  11  there is disposed a blower  10   a  and in the outdoor side discharge port  13  there is disposed another blower  10   b.  The numeral  4  stands for a compressor and the numeral  5  denotes an expansion valve, which may however be replaced by a capillary tube for a small capacity. They are connected to a refrigerant pipe  9  to form a conventional refrigeration cycle. Between the indoor or outdoor side intake port  12  or  14  and the dampers facing them  33  and  34  or  35  and  36  there are provided filters  15 . The compressor  4  mentioned above may be installed outside of the case  1  depending on its capacity. 
     The operation at cooling mode for the above-mentioned arrangement according to the invention will be described with reference to FIG.  2 . Here, the air flow route shown as dotted lines represents the air flow through the condenser  3  under the partition plate  21 . 
     When the dampers  31  and  33 , which are provided between the indoor air route and the evaporator  2 , and the dampers  36  and  38 , which are provided between the outdoor air route and the condenser  3 , are opened, while the rest dampers  32 , 34 , 35  and  37  are closed, the warmed air in the room flows through the indoor air intake port  12  to the evaporator  2 , where it is cooled, and then the cooled air enters the room through the indoor air discharge port  11 . On the other hand, the external air which has been introduced through the external air intake port  14  absorbs heat while passing the condenser  3  and is exhausted to the outside through the outdoor discharge port  13 , whereby the room cooling is accomplished. 
     In such a case of cooling mode, for example, when the opening for the opened dampers  31 , 33 , 36  and  38  is adjusted at around 70% and that for the previously closed dampers  32 , 34 , 35  and  36  is adjusted at 30%, then 70% of cold indoor air and 30% of warm outdoor air for ventilating will pass through the evaporator  2  to result in a fresh and cooled air mixture which is supplied to the room. At that time, the condensate water is produced in the evaporator  2  and then spreaded on the condenser  3 , which improves the thermal efficiency of the condenser. In other words, the cooling action of the condenser is conducted combinedly through the air cooling and the water cooling. The lowered temperature of the mixed air consisting of 70% of warm external air and 30% of cold indoor air which flows through the condenser  3  contributes to the increase of the heat efficiency to remove heat from the condenser. 
     In case of heating mode as depicted in FIG. 3, in contrast to the foregoing, the dampers  32  and  34  located between the indoor air route and the condenser  3  and the dampers  35  and  37  located between the outdoor air route and the evaporator  2  are opened, while the rest dampers  31 , 33 , 36  and  38  are closed. Then the circulating indoor air is caused by the blower  10   a  to flow from the indoor air intake port  12  through the condenser  3  to be heated thereby before it returns to the room through the indoor air discharge port  11 . On the other hand, the external air from the external air intake port  14  is sucked by the blower  10   b  to flow through the evaporator  2 , where the air gives off heat, to be exhausted to the outdoor atmosphere through the external air discharge port  13 , whereby the room heating cycle is completed. 
     In such a heating mode, if the dampers  32 , 34 , 35  and  37  are adjusted to be opened at around 70% instead of full opening and the group of dampers  31 , 33 , 36  and  38  are partly opened at around 30% instead of full closing, 70% of warm indoor air and 30% of cold outdoor air for ventilation would pass through the condenser  3  and be heated there, so that a fresher and warm air mixture can be supplied to the room. The warmer air mixture consisting of 70% of cold outdoor air and 30% of warm indoor air could be supplied to the evaporator  2  and therefore the capability or efficiency of removing heat from the evaporator would be improved mainly due to a larger temperature difference. 
     Now another embodiment of the present invention will be described with regard to FIGS. 4 and 5. As seen in the figures, the room R is provided with a humidity sensor  7  and there is additionally installed a reheater  6  between the indoor air discharge port  11  and the evaporator  2 . Specifically, this reheater  6  is an auxiliary condenser, which is connected between the condenser  3  and the expansion valve  5 , as depicted in FIG.  5 . Further, a humidifier  8  is installed between the indoor air discharge port  11  and the condenser  3 . 
     The numeral  41  denotes an accumulator,  42  denotes an oil separator,  43  denotes a filler dryer,  44  and  45  denote solenoid valves, for which further explanation is omitted because they are components usually employed in a refrigerant cycle. 
     The arrangement constructed as above is so operated in a cooling mode that the heat emission from the condenser  3  or the refrigerating fluid is regulated by controlling the air flow on the condenser blower  10   b  located at the outdoor discharge port  13  in response to the variation in the current relative humidity detected by the humidity sensor  7 . Accordingly, the heat content included in the refrigerant fluid flowing through the reheater  6 , which is connected subsequent to the condenser  3 , is varied so as to appropriately adjust the temperature of the air flowing from the evaporator  2  toward the indoor air discharge port  11  by the emitted heat from the reheater  6  to resultantly adjust the relative humidity of the room. At that time, the refrigerating capacity would need to be increased with the increase of quantity of reheating, but the refrigerating capacity would increase because the refrigerant entering the expansion valve  5  will be cooled more corresponding to the increased reheat, whereby the drop in the refrigerating capacity due to the reheating is not resulted. If the relative humidity in the room is below the target value, it can be raised by lowering the temperature through normal cooling operation. And when the humidity sensor has detected that the indoor relative humidity is below the target value at a heating mode, a humidifier  8  is operated to increase the humidity of the air emerging from the condenser  3  to the indoor air discharge port  11 . When the relative humidity in the room is above the target value, a normal heating operation will be needed to lower it. 
     The opening regulation for the dampers  31  through  38 , the operation of the reheater  6  and the humidifier  8 , the flow rate of the blower  10   a  or  10   b  or the like, as mentioned above, are naturally conducted by a controller (not shown) depending on the humidity sensor  7  for detecting the indoor humidity, a temperature sensor which was not shown, and preset values inputted optionally by the user. The numeral  46  denotes a humidity controller which may constitute a part of the controller or a separate unit. 
     As clear from the above, the air conditioner for combined cooling and heating according to the present invention, which device is a new construction based on an ordinary refrigerant cycle, can be operated either for cooling or for heating and with a high efficiency optionally by fully opening or closing, or regulating the opening for the flow of the entering or leaving air, or controlling the direction of the air flow. Furthermore, the reheater and the humidifier added on a conventional refrigeration cycle enable a precise regulation and maintenance of the indoor temperature and humidity without additional apparatus. 
     The present invention is by no means restricted to the above-described preferred embodiments, but covers all variations that might be implemented by using equivalent functional elements or devices that would be apparent to a person skilled in the art, or modifications that fall within the spirit and scope of the appended claims.