Patent Publication Number: US-2021180836-A1

Title: Apparatuses and methods for modular heating and cooling system

Description:
FIELD OF THE DISCLOSURE 
     This disclosure relates to heating and cooling systems. More particularly, the disclosure relates to modular heating and cooling systems comprising one or more heat exchangers and fluid loops. 
     BACKGROUND 
     Heating and cooling systems, such as air conditioner systems for interior spaces, typically include heat exchangers and fluid that is cycled through the heat exchangers to provide the required heating and/or cooling. Examples of typical heat exchangers include evaporators and condensers. 
     Modular heating and cooling systems may include one or more modules connected to a fluid input and fluid output. A module of a conventional modular system typically consists of two heat exchangers: a first heat exchanger dedicated as an evaporator to cool a “cooling” or “cold” fluid; and the second heat exchanger functioning as a condenser to provide heat to a “heating” or “hot” fluid. This set up is similar to a basic refrigeration cycle. A “source” fluid may also provide either heat or cooling to the system by acting as heat source or heat sink. In some cases, reversing valves are used to reverse the refrigerant cycle between evaporator and condenser heat. In conventional systems, control valves are typically used to switch the liquid flow among the heating fluid, cooling fluid and source fluid depending on the load requirement. 
     Various conventional fluid switching methods used in these scenarios include three-way valves, two-way valves and varying end caps. These conventional methods result in mixing of the cooling, heating and source fluids. As a result, such systems require these three liquid loops to be of the same type of solution. As an example, if one fluid loop requires glycol mix at certain percentage (e.g. because the fluid loop is partially outdoors), the other fluid loops must be the same percentage glycol. This may cause inefficiencies in the system because glycol solutions are typically less effective for heat transfer, and more expensive, than water without glycol. 
     SUMMARY 
     According to one aspect, there is provided a heating and cooling apparatus comprising: a first heat exchanger, a second heat exchanger and a third heat exchanger; a compressor; a first fluid line for a first fluid coupled to the first heat exchanger; a second fluid line for a second fluid coupled to the second heat exchanger; a refrigerant line system coupled to the first, second and third heat exchangers and configurable to: direct refrigerant fluid through the first and third heat exchangers and the compressor, to cool the first fluid, in a first mode of operation; direct the refrigerant fluid through the second and third heat exchangers and the compressor, to heat the second fluid, in a second mode of operation; and direct the refrigerant fluid through the first and second heat exchangers and the compressor, to cool the first fluid and heat the second fluid, in a third mode of operation. 
     In some embodiments: the refrigerant line system is configurable, for the first mode of operation, to direct the refrigerant through the third heat exchanger in a first flow direction such that the third heat exchanger functions as a heat sink; and the refrigerant line system is configurable, for the second mode of operation, to direct the refrigerant through the third heat exchanger in a second flow direction such that the third heat exchanger functions as a heat source. 
     In some embodiments, the first fluid line and the second fluid line are independent and separate from the one another, thereby maintaining separation of the first and second fluids. 
     In some embodiments: the first fluid line comprises a first fluid input connectable to a first fluid-in pipeline and a first fluid output connectable to a first fluid-out pipeline; and the second fluid line comprises a second fluid input connectable to a second fluid-in pipeline and a second fluid output connectable a second fluid-out pipeline. 
     In some embodiments, the heating and cooling apparatus is further operable in a standby mode of operation. 
     In some embodiments, each of the first, second and third fluid lines comprises a respective valve to control flow therethrough. 
     In some embodiments, the apparatus further comprises a control module connected to the refrigerant line system and operable to select between the modes of operation. 
     In some embodiments, the refrigerant line system comprises a plurality of interconnected refrigerant line segments and a plurality of valves configurable to provide: a first refrigerant loop for the first mode of operation; a second refrigerant loop for the second mode of operation; and a third refrigerant loop for the third mode of operation. 
     In some embodiments, the control module is connected to and controls the plurality of valves. 
     In some embodiments, the first mode of operation is a cooling-only mode of operation, the second mode of operation is a heating-only mode of operation, and the third mode of operation is a concurrent heating and cooling mode of operation. 
     In some embodiments, the third heat exchanger is an air coil heat exchanger. 
     In some embodiments, the apparatus further comprises a third fluid line for a third fluid coupled to the third heat exchanger such that the third fluid absorbs heat from the refrigerant fluid in the first mode of operation and the third fluid provides heat to the refrigerant fluid in the second mode of operation. 
     In some embodiments, at least one of the first, second and third fluids is substantially glycol free water, and at least one other of the first, second and third fluids is a glycol solution. 
     In some embodiments, at least one of the first, second and third fluid lines comprises a respective cleanable strainer upstream of the corresponding first, second or third heat exchanger. 
     According to another aspect, there is provided a heating and cooling system comprising: at least one heating and cooling apparatus as claimed in claim  1 , each heating and cooling apparatus connectable to the first fluid-in pipeline, the first fluid-out pipeline, the second fluid-in pipeline and the second fluid-out pipeline. 
     In some embodiments, each at least one said heating and cooling apparatus further comprising a third fluid line, for a third fluid, coupled to the third heat exchanger such that the third fluid absorbs heat from the refrigerant fluid in the first mode of operation and the third fluid provides heat to the refrigerant fluid in the second mode of operation, wherein the third fluid line is connectable to a third fluid-in pipeline, a third fluid-out pipeline. 
     In some embodiments, a current mode of operation of the plurality of modes of operation is independently selectable for each said at least one heating and cooling apparatus. 
     According to another aspect, there is provided a method for making a heating and cooling apparatus comprising: coupling a first fluid line to a first heat exchanger; coupling a second fluid line to a second heat exchanger; coupling a refrigerant line system to the first and second heat exchangers and to a third heat exchanger, wherein the refrigerant line system is configurable to: direct refrigerant fluid through the first and third heat exchangers and the compressor for cooling the first fluid in a first mode of operation; direct refrigerant the fluid through the second and third heat exchangers and the compressor for heating the second fluid in a second mode of operation; and direct refrigerant fluid through the first and second heat exchangers and the compressor for cooling the first fluid and heating the second fluid for a third mode of operation. 
     In some embodiments, the method further comprises: for a first mode of operation, configuring the refrigerant line system to direct the refrigerant through the third heat exchanger in a first flow direction such that the third heat exchanger functions as a heat sink; and the refrigerant line system is configured, in the second mode of operation, to direct the refrigerant through the third heat exchanger in a second flow direction such that the third heat exchanger functions as a heat source, the second flow direction being the reverse of the first flow direction. 
     In some embodiments, the method further comprises interconnecting a plurality of refrigerant line segments and a plurality of valves to provide the refrigerant line system that provides a first refrigerant loop for the first mode of operation; a second refrigerant loop for the second mode of operation; and a third refrigerant loop for the third mode of operation. 
     Other aspects and features of the present disclosure will become apparent to those ordinarily skilled in the art upon review of the following description of the specific embodiments of the disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present disclosure will be better understood having regard to the drawings in which: 
         FIG. 1  is a block diagram of an example heating and cooling apparatus according to some embodiments operating in a cooling-only mode of operation; 
         FIG. 2  is a block diagram of a first (cooling) heat exchange module of the apparatus of  FIG. 1  according to some embodiments; 
         FIG. 3  is a block diagram of a second (heating) heat exchange module of the apparatus of  FIG. 1  according to some embodiments; 
         FIG. 4  is a block diagram of a third (source) heat exchange module of the apparatus of  FIG. 1  according to some embodiments; 
         FIG. 5  is a block diagram showing another example of a third (source) heat exchange module according to some embodiments; 
         FIG. 6  is the block diagram of the apparatus of  FIG. 1 , but operating in a heating-only mode of operation; 
         FIG. 7  is the block diagram of the apparatus of  FIG. 1 , but operating in a concurrent heating and cooling mode of operation; 
         FIG. 8  is a block diagram of the heating and cooling apparatus of  FIGS. 1, 6 and 7  and further including an example control module; 
         FIG. 9  is a block diagram showing additional detail of the example control module of  FIG. 8 ; 
         FIG. 10  is a functional block diagram of an example modular heating and cooling system according to some embodiments; 
         FIG. 11  is a functional block diagram of another example modular heating and cooling system according to some embodiments; 
         FIG. 12  is a flowchart of a method for making a heating and cooling apparatus according to some embodiments; and 
         FIG. 13  is a flowchart of a method according to yet another embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     As discussed above, conventional modular heating and cooling systems use the same fluid mixture for heating and cooling cycles. According to some embodiments of the disclosure, there is provided a modular versatile thermal system comprising dedicated and independent heating and cooling fluid loops, such that the heating and cooling fluids do not need to mix. 
     The modular heating and cooling system described herein comprises one or more heating and cooling apparatuses (i.e. modules) that may each be independently set to: heating-only mode of operation; cooling-only mode of operation; and concurrent heating and cooling mode of operation. 
     The heating and cooling apparatuses may be independently and individually set to one of the modes of operation to satisfy the cooling and heating requirements of a building or process. In other words, each heating and cooling apparatus may be set to any one of the three modes of operation at any given time, thereby providing flexibility in matching the required heating and/or cooling capacity any time. 
     The terms “heating-only”, “cooling-only” and “concurrent heating and cooling” refer to the heating and cooling of the respective heating/cooling fluids in the heating and cooling loops. The term “cooling-only” simply refers to cooling of the cooling fluid (with the heating fluid not being heated by the apparatus in that mode). Similarly, “heating-only” simply refers to heating of the heating fluid (with the cooling fluid not being cooled by the apparatus in that mode). These terms do not mean that no heat is radiated or absorbed at other stages of the refrigeration cycle. These modes of operation may also be referred to as “first, second and third” modes of operation. Similarly, the heating fluid and cooling fluid may be referred to as “first” and “second” fluids. Furthermore, embodiments are not limited to the particular “heating-only”, “cooling-only” and “concurrent heating and cooling” modes of operation described herein. 
     For each heating and cooling apparatus, the cooling fluid loop is coupled to a first heat exchanger (e.g. evaporator) configured for cooling. The heating fluid loop is coupled to a second heat exchanger (e.g. condenser) configured for heating. The apparatus also includes a third heat exchanger, which may act as a heat source for the heating-only mode of operation and may also act as a heat sink for the cooling-only mode of operation. The system further includes a refrigerant line system that selectively directs flow of a refrigerant fluid to the first, second and third heat exchangers. The function of selectively directing flow may be accomplished with a set of valves controlled by the apparatus. The refrigerant line system may be configured to reverse the flow of direction of the refrigerant through the third heat exchanger to select between the heat sink and heat source function. In other words, the refrigerant line system is configurable to provide different refrigerant loops for the different modes of operation. 
     In the cooling-only mode of operation, the refrigerant loop is set to flow through the first heat exchanger, to cool the cooling fluid, and the third heat exchanger, with the third heat exchanger acting as a heat sink. In the heating-only mode of operation, the refrigerant loop is set to flow through the second heat exchanger, to heat the heating fluid, and the third heat exchanger, with the third heat exchanger acting as a source. In the concurrent cooling and heating mode of operation, the refrigerant loop is set to flow through the first heat exchanger, to cool the cooling fluid, and the second heat exchanger, to heat the heating fluid. The various modes of operation may be selected and controlled by configuring the set of valves (e.g. solenoid/motorized valves and reversing valve). 
     According to an aspect, the heating, cooling, and source loops are separate and independent such that the heating fluid, the cooling fluid and the source fluid (if present) do not mix. In conventional systems where the fluids mix, a single fluid (typically containing a percentage of glycol) is used for the heating, cooling and source loops. By providing separate, independent fluid loops, according to the present disclosure, different fluids may be used in different loops. This may, for example, eliminate the need for unnecessarily filling loops with glycol. This, in turn, may result in greater efficiency advantages due to the fact that water (without glycol) may be better heat transfer efficiency than glycol and may have a lower cost. 
       FIG. 1  is a functional block diagram of an example heating and cooling apparatus  100  according to some embodiments. The apparatus  100  may form a module of a modular heating and cooling system, such as the system  1000  shown in  FIG. 10 . Multiple such apparatuses may have arranged to work together in the modular system to provide desired heating and cooling (e.g. in a building and/or process). 
     The heating and cooling apparatus  100  has the following modes of operation: (1) cooling-only; (2) heating-only; (3) concurrent cooling and heating; and optionally (4) standby. Other modes of operation may be implemented as well. The heating and cooling apparatus  100  is shown operating in the cooling-only mode of operation in  FIG. 1 . 
     The heating and cooling apparatus  100  includes a first heat exchange module  104  for cooling a cooling fluid and a second heat exchange module  106  for heating a heating fluid. By way of example, the first heat exchange module  104  may comprise an evaporator, and the second heat exchange module  106  may comprise a condenser. The heating and cooling apparatus  100  further includes a third “source” heat exchange module  108  that acts as either a heat sink or a heat source depending on the current mode of operation of the heating and cooling apparatus  100 . The heating and cooling apparatus  100  further includes a refrigerant line system  110  with multiple refrigerant loop configurations. The refrigerant line system  110  is configurable to select between the modes of operation, as will be described in detail below. 
       FIG. 1  also shows example cooling fluid-in pipeline  114   a , cooling fluid-out pipeline  114   b , heating fluid-in pipeline  116   a , heating fluid-out pipeline  116   b , source fluid-in pipeline  118   a  and source fluid-out pipeline  118   b  to which the apparatus  100  is connected. 
     Cooling fluid (not visible) flows into the first heat exchange module  104  (via cooling fluid input  120   a ) from the cooling fluid-in pipeline  114   a  and exits from the first heat exchange module  104  (via cooling fluid output  120   b ) to the cooling fluid-out pipeline  114   b.    
     Similarly, heating fluid (not visible) flows into the second heat exchange module  106  (via heating fluid input  122   a ) from the heating fluid-in pipeline  116   a  and exits from the second heat exchange module  106  (via heating fluid output  122   b ) to the heating fluid-out pipeline  116   b.    
     Source fluid (not visible) flows into the third heat exchange module  108  (via source fluid input  124   a ) from the source fluid-in pipeline  118   a  and exits from the third heat exchange module  108  (via source fluid output  124   b ) to the source fluid-out pipeline  118   b.    
     The fluid-in and fluid-out pipelines  114   a ,  114   b ,  116   a ,  116   b ,  118   a  and  118   b  may be referred to as “header pipes” or “header pipelines”. Flow of the cooling, heating and source fluids through the corresponding heat exchange modules  104 ,  106  and  108  is controlled by valves  119   a ,  119   b  and  119   c  respectively, as discussed below. The valves  119   a ,  119   b  and  119   c  are motorized valves in this example embodiment, although embodiments are not limited specifically to motorized valves. For example, solenoid (e.g. solenoid piloted), pneumatic or other types valves or other flow control means may be used in other embodiments. 
     The cooling, heating, and source lines within the apparatus  100  are independent such that the cooling, heating, source fluids do not mix. Thus, different fluids may be used for different lines. At least one of the cooling, heating and source fluids may be substantially glycol free water, and at least one other of the cooling, heating and source fluids may be a glycol solution. For example, the source fluid may be a glycol solution, while the heating liquid and the cooling liquid may each be water (glycol free). The heating and cooling fluids may alternatively be different. As yet another option, each of the cooling, heating and source fluids may be glycol-free water, or each may comprise a glycol solution. Other fluid solutions and combinations are also possible. Water may be cheaper and better for heat exchange, while a glycol solution may resist freezing and be more suitable for source pipelines that extend into outdoor areas. 
     The apparatus  100  includes a compressor  112  which is shown as part of the refrigerant line system  110  in this embodiment. In other embodiments, the compressor  112  may be external to and connected to the refrigerant line system  110 . The refrigerant line system  110  controls the flow of the refrigerant through the corresponding heat exchangers  104 ,  106  and  108  and the compressor  112 , as discussed in more detail below. The compressor  112  shown in  FIG. 1  is a tandem compressor, although embodiments are not limited to any particular compressor type. The compressor  112  may also be single, multiple in tandem, cascade, in series, parallel, fixed speed or variable speed. 
     The refrigerant line system  110  is configurable to selectively direct refrigerant fluid through the heat exchange modules  104 ,  106  and  108  and the compressor  112  depending on the selected mode of operation. In this specific example, the refrigerant line system  110  includes refrigerant line segments  126   a  to  126   i  and valves  128   a  to  128   d ,  130 ,  132   a ,  132   b ,  134   a  and  134   b  interconnecting the heat exchange modules  104 ,  106  and  108  and the compressor  112 . The refrigerant line segments  126   a  to  126   i  may comprise pipes, other tubing and/or other structure suitable for conveying the refrigerant fluid. The specific arrangement and function of the line segments  126   a  to  126   i  and valves  128   a  to  128   d ,  130 ,  132   a ,  132   b ,  134   a  and  134   b  will be discussed in more detail below. However, it is to be understood that embodiments are not limited to the particular components and arrangement of the example refrigerant line system  110 . Refrigerant line systems of other embodiments may comprise other arrangements of fluid lines and flow control devices to selectively direct the refrigerant for different modes of operations. 
     Refrigerant line segment  126   a  extends into the first heat exchange module  104 . 
     Refrigerant line segment  126   b  extends (as output) from the first heat exchange module  104  to an input of the compressor  112 . Refrigerant line segment  126   b  the continues from the output of the compressor  112  to a first port  131   a  of the reversing valve  130 . The reversing valve  130  has multiple flow configuration settings. 
     Refrigerant line segment  126   c  extends from a second port  131   b  of the reversing valve  130  and into the second heat exchange module  106 . 
     Refrigerant line segment  126   d  extends from a third port  131   c  of the reversing valve  130  back to the refrigerant line segment  126   b  upstream of the compressor  112 . 
     Refrigerant line segment  126   e  extends from a fourth port  131   d  of the reversing valve and into the third heat exchange module  108 . 
     Refrigerant line segment  126   f  extends (as output) from the third heat exchange module  108  and then continues as line segment  126   g.    
     Refrigerant line segment  126   g  extends through optional filter dryer  150  and continues thereafter to connect with segments  126   a  and  126   h.    
     Refrigerant line segment  126   h  extends from the connection point of segments  126   a  and  126   g  back to an intersection/connection with line segments  126   f  and  126   g  (upstream of one-way check valve  128   d  discussed below). 
     Refrigerant line segment  126   i  extends (as output) from the second heat exchange module  106  to join line segment  126   g  upstream of the filter dryer  150 . 
     One-way check valves  128   a ,  128   b ,  128   c  and  128   d  are included on refrigerant fluid line segments  126   b ,  126   i ,  126   d  and  126   g  respectively. The check valves  128   a ,  128   b ,  128   c  and  128   d  limit the flow of the refrigerant fluid therein to a single direction as indicated by small arrows. As mentioned above, embodiments are not limited to particular types of valves or valve arrangements. In other embodiments, different valves (one-way or otherwise) and/or different flow control means may be used in addition to, or in place of, the one-way check valves of this specific example. 
     First and second valves  132   a  and  132   b  are included on line segments  126   h  and  126   a  respectively) and may be opened or closed to turn on/off the flow through the corresponding line segments  126   h  and  126   a  respectively. The valves  132   a  and  132   b  are solenoid valves that are controlled electrically in this example. However, other valve types (e.g. motorized, pneumatic, etc.) or other flow control means may be used to turn flow on/off, and embodiments are not limited to solenoid valves. 
     First and second expansion valves  134   a  and  134   b  are located just downstream of the solenoid valves  132   a  and  132   b , respectively. The expansion valves can of any type of valves to perform the function. By way of example, the valves may be thermal expansion valves (known as T-X valves) or electronic expansion valves or any other flow metering device adjusted by the system controller. The expansion valves  134   a  and  134   b  cause expansion of refrigerant fluid flowing there though to create a boiling mixed gas/liquid state for the refrigeration cycle. 
     The refrigerant line system  110  in this example also includes a reversing valve  130  that controls the flow of fluids between line segments  126   b ,  126   c ,  126   d  and  126   e , as explained in more detail below. The reversing valve  130  may be activated by a motor  163  (or alternatively a solenoid) through commands received from the system controller. In other embodiments, rather than a single reversing-type valve, a combination of other valves may be used to perform the reversing valve function. 
       FIG. 2  is a block diagram of the first (cooling) heat exchange module  104  in  FIG. 1 . The heat exchange module  104  includes a first heat exchanger  136  (e.g. evaporator). Refrigerant may flow into the first heat exchanger  136  via refrigerant line segment  126   a  and exit the first heat exchanger  136  via refrigerant line segment  126   b . The cooling fluid flows through a cooling fluid line  138 , which includes the cooling fluid input  120   a  and output  120   b . Flow through the cooling fluid line  138  may be turned on/off by opening or closing valve  119   a.    
     The cooling fluid line  138  is coupled to the first heat exchanger  136  for giving heat to the refrigerant fluid. For example, in the case of an evaporator, the process of the refrigerant fluid evaporating requires the refrigerant fluid to absorb heat, thereby cooling the cooling fluid. The cooling fluid line  138  is separate from and does not mix with the refrigerant fluid in the heat exchanger  136  (indicated by the stippled line portion of the cooling fluid line  138 ). The cooling fluid line  138  and the cooling fluid-in and fluid out pipelines  114   a  and  114   b  (shown in  FIG. 1 ) are typically, but not necessarily in all embodiments, part of a closed loop. By way of example, the cooling fluid-in and fluid out pipelines  114   a  and  114   b  may both be in fluid communication with a cooling fluid reservoir. 
     The cooling fluid line  138  may comprise tubing (e.g. pipe, hose, etc.) and/or any other structure suitable for conveying the cooling fluid. The thermal coupling of the cooling fluid line and the first heat exchanger  136  may be accomplished in any suitable manner. For example, the cooling fluid line may have one or more coils (not shown) around, within, or adjacent to the refrigerant path in the first heat exchanger  136 . 
       FIG. 2  also shows optional strainer  140   a  in the cooling fluid line  138  (upstream of the first heat exchanger  136 ) for straining debris from the cooling fluid. The strainer  140   a  may be accessible for cleaning to periodically remove the strained debris. 
       FIG. 3  is a block diagram showing additional detail of the second (heating) heat exchange module  106  in  FIG. 1 . The second heat exchange module  106  includes a second heat exchanger  142  (e.g. condenser). Refrigerant fluid may flow into the second heat exchanger  142  via refrigerant line segment  126   c  and exit the second heat exchanger  142  via refrigerant line segment  126   i . The heating fluid flows through a heating fluid line  144 , which includes the heating fluid input  122   a  and output  122   b . Flow of the heating fluid through the heating fluid line  144  may be turned on/off by opening or closing valve  119   b    
     The heating fluid line  144  is coupled to the second heat exchanger  142  for absorbing heat from the refrigerant fluid. For example, in the case of a condenser, the process of the refrigerant fluid condensing requires the refrigerant fluid to radiate heat, thereby heating the heating fluid. The heating fluid line  144  and the heating fluid-in and fluid out pipelines  116   a  and  116   b  (shown in  FIG. 1 ) are typically, but not necessarily in all embodiments, part of a closed loop. By way of example, the heating fluid-in and fluid out pipelines  116   a  and  116   b  may both be in fluid communication with a heating fluid reservoir. 
     The heating fluid line  144  may comprise tubing (e.g. pipe, hose, etc.) and/or other structure suitable for conveying the heating fluid. The thermal coupling of the heating fluid line  144  and refrigerant fluid in the second heat exchanger  142  may be accomplished in any suitable manner. For example, the heating fluid line  144  may comprise one or more coils (not shown) around, within, or adjacent to the second heat exchanger  142 . 
       FIG. 3  also shows optional strainer  140   b  in the heating fluid line  144  (upstream of the second heat exchanger  142 ) for straining debris from the heating fluid. The strainer  140   b  may be accessible to periodically remove the strained debris. 
       FIG. 4  is a block diagram showing additional detail of the third (source) heat exchange module  108  in  FIG. 1 . The third heat exchange module  108  includes a third heat exchanger  146  that acts as a heat sink (e.g. condenser) or a heat source (e.g. evaporator) depending on the direction of flow of the refrigerant fluid, which is reversible. The refrigerant fluid may flow into the third heat exchanger  146  via refrigerant line segment  126   e  and exit the third heat exchanger  146  via refrigerant line segment  126   f , or vice versa depending on the flow direction. The source fluid flows through a source fluid line  148 , which includes the source fluid input  124   a  and output  124   b . Flow of the source fluid through the source fluid line  148  may be turned on/off by opening or closing the valve  119   c . Other types of valves also can be used. 
     The source fluid line  148  is coupled to the third heat exchanger  146 . If the third heat exchanger  146  is functioning as a heat sink, heat is absorbed from the refrigerant fluid into the source fluid. Conversely, if the third heat exchanger  146  is functioning as a heat source, heat is absorbed from the source fluid into the refrigerant fluid. The source fluid line  148  and the source fluid-in and fluid-out pipelines  118   a  and  118   b  (shown in  FIG. 1 ) are typically, but not necessarily in all embodiments, part of a closed loop. By way of example, the source fluid-in and fluid out pipelines  118   a  and  118   b  may both be in fluid communication with a source fluid reservoir. The source fluid loop can be fed by geothermal loop, cooling tower, boiler, etc. 
     The source fluid line  148  may comprise tubing (e.g. pipe, hose, etc.) and/or other structure suitable for conveying the heating fluid. The thermal coupling of the source fluid line  148  and the third heat exchanger  146  may be done in any suitable manner. For example, the source fluid line  148  may comprise one or more coils (not shown) around, within, or adjacent to the second heat exchanger  142 . 
       FIG. 4  also shows optional strainer  140   c  in the source fluid line  148  (upstream of the third heat exchanger  146 ) for straining debris from the source fluid. The strainer  140   c  may be accessible to periodically remove the strained debris. 
     The terms “first heat exchange module,” “second heat exchange module” and “third heat exchange module” used herein are for ease of description of functionality and do not require that the modules be separately housed or spatially segregated from the remainder of the heating and cooling apparatus  100  of  FIG. 1 . In some embodiments, a “heat exchange module” may simply comprise a heat exchanger with the corresponding fluid lines coupled thereto. For example, the first heat exchanger  104  shown in  FIGS. 1 and 2  may consist of the first heat exchanger  136  coupled to the first fluid line  138  and the refrigerant line system  110 . 
       FIG. 5  is a block diagram showing an optional configuration of a third (source) heat exchange module  508  for some embodiments. Rather than a source fluid, an air-coil type heat exchanger  546  with optional fan  548  is used. In this example, air is either a cool source for cooling the refrigerant fluid or a heat source for heating the refrigerant fluid depending on the flow direction of the refrigerant fluid. 
     Turning again to  FIG. 1 , the cooling-only mode of operation will now be described. In this mode of operation, the refrigerant line system  110  creates a refrigeration cycle/loop with the first and third heat exchange modules  104  and  108  (with the second heat exchange module  106  inactive). Arrows on the relevant refrigerant line segments are shown to illustrate the direction of flow of the refrigerant fluid, cooling fluid and source fluid. Accumulator/s may be included (installed) on the suction line  126   b  position. Liquid receiver/s may be included (installed) on the liquid line upstream or downstream of the filter dryer  150 . 
     The first solenoid valve  132   a  is closed to prevent refrigerant fluid from flowing through refrigerant line segment  126   h . The second solenoid valve  132   b  is opened to allow flow through refrigerant line segment  126   a . As a result, refrigerant at or near boiling (due to expansion valve  134   b ) flows into the first heat exchange module  104  where it evaporates in the first heat exchanger  136  ( FIG. 2 ) and absorbs heat from the cooling liquid. The refrigerant fluid the exits the first heat exchange module  104  and travels to the compressor  112  via refrigerant line segment  126   b  where it is compressed into a heated liquid and continues on to the reversing valve  130 . 
     The reversing valve  130  is set to a first setting (referred to herein as “setting  1 ”) to direct the refrigerant fluid via refrigerant line segment  126   e  into the third heat exchange module  108  where it transfers heat to the source fluid. More specifically, the refrigerant passes through the third heat exchanger  146  shown in  FIG. 5 , which functions as a condenser heat sink in this mode. The cooled refrigerant then travels back toward the expansion valve  134   b  via refrigerant line segments  126   f  and  126   g . The refrigerant also passes through the filter dryer  150 . Filter dryer in refrigeration system may have two functions: adsorb contaminants like moisture; and provide physical filtration. 
     In this cooling-only mode of operation, the valves  119   a  and  119   c  are opened so that the cooling fluid and source fluids flow through the first and third heat exchange modules  104  and  108  respectively. The cooling fluid enters from cooling fluid-in pipeline  114   a  and is cooled in the first heat exchange module  104  before exiting to the cooling fluid-out pipeline  114   b . Heat is vented to the source fluid in the third heat exchange module  108  as described above. 
     The valve  119   b  may be closed so that heating fluid does not flow through the second heat exchange module  106 , which is inactive in this mode. 
       FIG. 6  is the block diagram of  FIG. 1 , but in the heating-only configuration. In this mode of operation, the refrigerant line system  110  creates a refrigeration cycle using the second and third heat exchange modules  106  and  108  (with the first heat exchange module  104  inactive). Arrows on the relevant refrigerant line segments are shown to illustrate the direction of flow of the refrigerant fluid, heating fluid and source fluid. 
     The first solenoid valve  132   a  is opened to allow refrigerant fluid to flowing through refrigerant line segment  126   h . The second solenoid valve  132   b  is closed to prevent flow through refrigerant line segment  126   a . As a result, cooled refrigerant fluid exits from the second heat exchange module  106  on refrigerant line segment  126   i  and then along a portion of refrigerant line segment  126   g  through the filter dryer  150 . The refrigerant fluid then travels through the expansion valve  134   a  and into the third heat exchanger  108  (via line segment  126   f ), which acts as an evaporator-heat sink for this flow direction. The refrigerant evaporates, thereby absorbing heat from the source fluid. The refrigerant fluid then flows from the third heat exchanger  108  along line segment  126   e  to the reversing valve  130 . 
     In this mode of operation, the reversing valve  130  is set to a second setting (referred to herein as “setting  2 ”) to re-direct the refrigerant fluid to line segment  126   d . The refrigerant fluid then travels along a portion of line segment  126   b  and into the compressor  112 . 
     The refrigerant fluid (now in heated gas form) exits the compressor  112  and is directed by the reversing valve  130  to line segment  126   c  where it re-enters the second heat exchanger  106 . In the second heat exchanger  106 , the refrigerant fluid travels through the second heat exchanger  142  ( FIG. 3 ) and transfers heat to the heating fluid. 
     In this heating-only mode of operation, the valves  119   b  and  119   c  are opened so that the heating fluid and source fluids flow through the second and third heat exchange modules  106  and  108  respectively. The heating fluid enters from heating fluid-in pipeline  116   a  and is heated in the second heat exchange module  106  before exiting to the heating fluid-out pipeline  116   b . Heat is absorbed from the source fluid in the third heat exchange module  108  as described above. 
     The valve  119   a  may be closed so that cooling fluid does not flow through the second heat exchange module  106 , which is inactive in this m ode. 
       FIG. 7  is the block diagram of  FIG. 1 , but in the concurrent heating and cooling configuration. In this mode of operation, the refrigerant line system  110  creates a refrigeration cycle using the first and second heat exchange modules  104  and  106  (with the third heat exchange module  108  inactive). Arrows on the relevant refrigerant line segments are shown to illustrate the direction of flow of the refrigerant fluid, heating fluid and source fluid. 
     The first solenoid valve  132   a  is closed to prevent refrigerant fluid from flowing through refrigerant line segment  126   h . The second solenoid valve  132   b  is opened to allow flow through refrigerant line segment  126   a . As a result, refrigerant in the boiling state (due to expansion valve  134   b ) flows into the first heat exchange module  104  where it evaporates in the first heat exchanger  136  ( FIG. 2 ) and absorbs heat from the cooling liquid. The refrigerant fluid then exits the first heat exchange module  104  and travels to the compressor via refrigerant line segment  126   b  where it is compressed into a heated gas and continues on to the reversing valve  130 . 
     In this mode, the reversing valve has the same “setting  2 ” configuration shown in  FIG. 6 , and thus directs the refrigerant fluid to line segment  126   c  and into the second heat exchanger. In the second heat exchanger  106 , the refrigerant fluid travels through the second heat exchanger  142  ( FIG. 3 ) and radiates heat, which is absorbed by the heating fluid. 
     In this concurrent heating and cooling mode of operation, the valves  119   a  and  119   b  are opened so that the cooling fluid and heating fluid flow through the first and second heat exchange modules  104  and  106  respectively. The valve  119   c  may be closed so that source fluid does not flow through the third heat exchange module  108 , which is inactive in this mode. 
     A modular system may include multiple heating and cooling apparatuses of the type shown in  FIGS. 1, 6 and 7 . For a concurrent heating and cooling mode of operation, cooling requirements may be satisfied before heating requirements or vice versa. When cooling requirements are satisfied before the heating requirements, the system (e.g. system  1000  in  FIG. 10 ) may activate additional apparatus(es) (i.e. module(s)) in the heating-only mode of operation to make up the additional required heating. In other cases, when heating requirements are satisfied before cooling, additional cooling may be provided by turning on one or more apparatuses for the cooling-only mode. Thus, the modular system described herein may provide flexibility for satisfying both heating and cooling demands at any time. 
     Optionally, the heating and cooling apparatus  100  has a stand-by mode of operation in which each of the valves  119   a ,  119   b  and  119   c  are closed to prevent cooling, heating and source fluid flow in the heating and cooling apparatus  100 . The solenoid valves  132   a  and  132   b  in the line system  110  are also closed to prevent refrigerant fluid from flowing. 
     The apparatus  100  shown in  FIGS. 1, 6 and 7  may further comprise a system for controlling one or more valves (such as the valves  119   a  to  119   c ,  130 ,  132   a ,  132   b ,  134   a  and/or  134   b ) in order to select between the various modes of operation described above. 
       FIG. 8  is a functional block diagram of the heating and cooling apparatus  100  of  FIGS. 1, 6 and 7  and further including an example control module  160 . In this example, the control module  160  is operably connected to each of the valves  119   a  to  119   c ,  130 ,  132   a ,  132   b , such that the control module can selectively open and close each of the valves  119   a  to  119   c ,  130 ,  132   a ,  132   b . The valves  119   a  to  119   c ,  130 ,  132   a ,  132   b  may also have variable flow speed settings in addition to simply “open” to control flow rates as desired. In this embodiment, the control module  160  is also connected to the expansion valves  134   a ,  134   b  to properly adjust refrigerant flow expansion. 
     More specifically, the control module  160  is connected to the valve  119   a  by a first operable connection  162   a  to control the cooling fluid flow. The control module  160  is connected to the valve  119   b  by a second operable connection  162   b  to control the heating fluid flow. The control module  160  is connected to the valve  119   c  by a third operable connection  162   c  to control the source fluid flow. The control module  160  is connected to the solenoid valve  132   a  by a fourth operable connection  162   d  to control the refrigerant fluid flow through line segment  126   h  and expansion valve  134   a . The control module  160  is connected to the solenoid valve  132   b  by a fifth operable connection  162   e  to control the refrigerant fluid flow through line segment  126   a  and expansion valve  134   b . The control module  160  is connected to the reversing valve  130  by a sixth operable connection  162   f  to control the refrigerant fluid flow paths through reversing valve  130 . In this example, the reversing valve is solenoid activated and the control module  160  is connected to the motor  163  of the reversing valve  130 . The control module  160  is al connected to the expansion valves  134   a ,  134   b  by seventh and eighth operable connections  162   g  and  162   h  respectively. 
     The operable connections  162   a  to  162   f  may each comprise a wired electrical connection, a wireless connection, or a combination of the two, for example. Embodiments are not limited to any particular type of connection for controlling the valves  119   a  to  119   c ,  130 ,  132   a  and  132   b . As mentioned above, the valves  119   a  to  119   c ,  132   a  and  132   b  in this example are each motorized, and the control module  160  may activate motors therein by electronic signals to open or close each valve  119   a  to  119   c ,  132   a  and  132   b . Other types of valves that are controllable by remote control means may also be used. 
     In other embodiments, the valves  119   a  to  119   c  (shown in  FIGS. 1 to 8 ) may be external to the heating and cooling apparatus  100  ( FIGS. 1 and 6 to 8 ) and/or may be omitted. For example, the control module  160  may only control the valves  132   a ,  132   b  and  130 , while heating, cooling and/or source fluid are controlled manually and/or by another electronic control system. 
       FIG. 9  is a block diagram showing additional detail of the example control module  160  of  FIG. 8 . The control module  160  in this embodiment includes a processor  164  and a memory  166  coupled to the processor. The memory  166  may include processor executable instructions stored thereon for controlling the processor  164  to perform functionality described herein. In some embodiments, the memory  166  may be internal to the processor  164 . The processor  164  is operably connected to the valves  119   a  to  119   c ,  132   a ,  132   b ,  134   a  and  134   b  (shown in  FIG. 8 ) via the connections  162   a  to  162   h.    
     In still other embodiments, one or more of the valves  119   a  to  119   c ,  132   a ,  132   b ,  134   a  and  134   b  may include its own computer processing means and/or memory for controlling the behavior of the valve. For example, one or more valves may be “smart valves” that are automatically responsive to one or more parameters such as user input, temperature/pressure data, signals from a control module of the apparatus or a remote computer system, etc. One or more valves may be in communication with each other and may be collectively configured to perform the controlling functionality described herein. In some embodiments, the one or more “smart valves” may communicate (e.g. wirelessly) with the control module  160 , or the control module  160  may be omitted in still other embodiments. 
     The processor  164  of the control module  160  in this example controls the valves  119   a  to  119   c ,  130 ,  132   a  and  132   b  to provide the various modes of operation of the heating and cooling apparatus  100  (shown in  FIGS. 1, 6 and 7 ) according to Table 1 below. 
     
       
         
           
               
               
               
               
               
             
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                 Cooling 
                 Heating 
                 Concurrent 
                   
               
               
                   
                 Only 
                 Only 
                 Heat/Cool 
                 Standby 
               
               
                   
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
            
               
                 Valve 119a 
                 Open 
                 Closed 
                 Open 
                 Closed 
               
               
                 (Cooling) 
               
               
                 Valve 119b 
                 Closed 
                 Open 
                 Open 
                 Closed 
               
               
                 (Heating) 
               
               
                 Valve 119c 
                 Open 
                 Open 
                 Closed 
                 Closed 
               
               
                 (Source) 
               
               
                 Reversing Valve 
                 Setting 1 
                 Setting 2 
                 Setting 2 
                 N/A 
               
               
                 130 setting 
                 (FIG. 1) 
                 (FIGS. 6, 7) 
                 (FIGS. 6, 7) 
               
               
                 Valve 132a 
                 Closed 
                 Open 
                 Closed 
                 Closed 
               
               
                 (Refrigerant) 
               
               
                 Valve 132b 
                 Open 
                 Closed 
                 Open 
                 Closed 
               
               
                 (Refrigerant) 
               
               
                   
               
            
           
         
       
     
     The control module  160  in this example further includes an optional user interface  168  for receiving input from a user. By way of nonlimiting example, the user interface may be used to: program the behavior of the processor  164 ; cause the processor  164  to activate one of the modes of operation described above; and/or obtain diagnostic data. 
     The control module  160  in this example includes an optional wired input/output port  170  and an optional wireless communication subsystem  172 , which are both operably connected to the processor  164 . The example wireless communication subsystem  172  includes transceiver  174  connected to antenna  176  for wireless communication. The processor may also be operably connected to one or more other devices including, but not limited to: one or more thermostats; one or more temperature and/or pressure sensors; one or more other heating and cooling apparatuses (i.e. modules); and a central computer control system. Such connections may be established via the input/output port  170  and/or via wireless communication subsystem  172 . 
     The processor  164  may optionally receive temperature, pressure and/or other signals or information from the temperature and/or pressure sensor(s) and/or may receive control signals from the thermostat(s). The processor  164  may be programmed to activate one or more of the modes of operation of the heating and cooling apparatus  100  based on such information. For example, the processor  164  may activate the heating-only mode if a temperature is below a threshold, and the processor  164  may activate the cooling-only mode if a temperature is below another threshold. A thermostat may cause similar actions by sending control signals to the processor  164 . 
     The control module  160  may optionally be controlled by a remote central computer control system (not shown), which may communicate with the processor  164 . The central computer control system may control a plurality of heating and cooling apparatuses (modules) according to cooling and heating needs. 
     In some embodiments, a user may use the user interface  168  or a remote computer in communication with the control module  160  to set a required amount of heating-only, cooling-only, or concurrent heating and cooling. The system then activates each of the heating and cooling apparatus(es) to operate one of the modes depending on the system requirements. For example, one or more may be set to cooling-only; one or more may be set to heating-only; and one or more may be set to concurrent heating and cooling. 
     The control module  160  may optionally communicate with control modules of other heating and cooling apparatuses in the modular system in order to provide heating and cooling requirements in conjunction with the other heating and cooling apparatuses. 
       FIG. 10  is a functional block diagram of an example modular heating and cooling system  1000  according to some embodiments. The system  1000  comprises four heating and cooling apparatuses (i.e. modules)  100   a ,  100   b ,  100   c , and  100   d . Each of the heating and cooling apparatuses  100   a ,  100   b ,  100   c , and  100   d  has a structure and function similar to the heating and cooling apparatus  100  shown in  FIGS. 1, 6 and 7  and described above. More specifically, the first heating and cooling apparatus  100   a  includes respective first, second and third heat exchange modules  104   a ,  106   a , and  108   a  and a refrigerant line system  110   a . The first heat exchange module  104   a  is coupled to the cooling fluid-in pipeline  114   a  and the cooling fluid-out pipeline  114   b . The second heat exchange module  106   a  is coupled to the heating fluid-in pipeline  116   a  and the heating fluid-out pipeline  116   b . The third heat exchange module  108   a  is coupled to the source fluid-in pipeline  118   a  and the source fluid-out pipeline  114   b.    
     The second heating and cooling apparatus  100   b  includes respective first, second and third heat exchange modules  104   b ,  106   b , and  108   b  and a refrigerant line system  110   b . The third heating and cooling apparatus  100   c  includes respective first, second and third heat exchange modules  104   c ,  106   b , and  108   c  and a refrigerant line system  110   c . The fourth heating and cooling apparatus  100   d  includes respective first, second and third heat exchange modules  104   d ,  106   d , and  108   d  and a refrigerant line system  110   d . Each of the second, third and fourth second heating and cooling apparatuses  100   b  to  100   d  are similarly connected to the cooling fluid-in pipeline  114   a , cooling fluid-out pipeline  114   b , the heating fluid-in pipeline  116   a , heating fluid-out pipeline  116   b , and the source fluid-in pipeline  118   a , source fluid-out pipeline  118   b.    
     The first heat exchange modules  104   a  to  104   d , the second heat exchange modules  106   a  to  106   d , the third heat exchange modules  108   a  to  108   d  and the refrigerant line systems  110   a  to  110   d  have similar structure and functionality as the corresponding modules shown in  FIGS. 1 to 7  and described above. 
     The heating and cooling apparatuses  100   a ,  100   b ,  100   c , and  100   d  may also each include a respective control module, similar to control module  160  shown in  FIGS. 8 and 9 , for controlling their heating and cooling functions. The heating and cooling apparatuses  100   a ,  100   b ,  100   c , and  100   d  may all be in communication with a central control system (e.g. a remote computer system) and/or in communication with each other. 
     Each of the heating and cooling apparatuses  100   a ,  100   b ,  100   c , and  100   d  may be independently set to a mode of operation including: cooling-only; heating-only; and concurrent heating and cooling, as described above. Other modes, such as standby, may also be selectable in some embodiments. The number of heating and cooling apparatus modules in a modular system (such as system  1000 ) may vary. 
       FIG. 11  is a functional block diagram of another example modular heating and cooling system  1100  according to some embodiments. The system  1100  is similar to the system  1000  shown in  FIG. 10 . However, rather than a third heat exchanger thermally couple to a source fluid line, the heating and cooling apparatuses  1100   a  to  1100   d  of the system  1100  each include a respective air coil heat exchanger  546   a ,  546   b ,  546   c  or  546   d . The air coil heat exchanger  546   a ,  546   b ,  546   c  and  546   d  each have a structure and function similar to the air coil heat exchanger  546  in  FIG. 5 . 
     The heating and cooling apparatuses  1100   a  to  1100   d  of the system  1100  also include first heat exchange modules  104   a  to  104   d , second heat exchange modules  106   a  to  106   d  and refrigerant line systems  110   a  to  110   d  that are similar to those shown in  FIG. 10 . 
       FIG. 12  is a flow chart of a method for making a heating and cooling apparatus according to some embodiments. The apparatus may be similar to the apparatus  100  shown in  FIGS. 1, 6 and 7 . 
     At block  1202 , a first fluid line is coupled to a first heat exchanger. The first fluid line may, for example, for a cooling fluid line, and the first heat exchanger may be configured for cooling the fluid in the cooling fluid line. 
     At block  1204 , a second fluid line is coupled to a second heat exchanger. The first fluid line may, for example, for a heating fluid line, and the second heat exchanger may be configured for heating the fluid in the heating fluid line. The first fluid line and the second fluid line may be independent and separate from the one another, thereby maintaining separation of the first and second fluids. 
     At optional block  1206 , the method further comprises coupling a third (e.g. source) fluid line to a third heat exchanger. However, the third heat exchanger may be an air coil heat exchanger without a third fluid line in some embodiments. 
     At block  1208 , a refrigerant line system is coupled to the first, second heat and the third heat exchanger. The refrigerant line system is configurable for selectively directing refrigerant fluid through: the first and third heat exchangers and a compressor for cooling the first fluid in a first mode of operation; the second and third heat exchangers and the compressor for heating the second fluid in a second mode of operation; and the first and second heat exchangers and the compressor for cooling the first fluid and heating the second fluid a for a third mode of operation. The refrigerant line system may be similar in function and structure to the example refrigerant line system  110  shown in  FIGS. 1, 6 and 7 . However, it is to be understood that the refrigerant line system may comprise other arrangements of fluid lines, valves and/or switches to perform the function of providing different refrigerant loops for the different modes of operation. 
     It is to be understood that the order of blocks  1202 ,  1204 ,  1206  and  1208  shown in  FIG. 12  and described above are not necessarily in chronological order. Step  1208  may be performed before steps  1202 ,  1204  and  1206 . Similarly, embodiments are not limited to any particular order for coupling the first, second and third heat exchangers to the corresponding first, second and third fluid lines. 
     More specifically, for the first mode of operation, the refrigerant line system is configured to direct the refrigerant through the third heat exchanger in a first flow direction such that the third heat exchanger functions as a heat sink. For the second mode of operation, the refrigerant line system is configured to direct the refrigerant through the third heat exchanger in a first flow direction such that the third heat exchanger functions as a heat source. 
     The method may further comprise making the refrigerant line system by interconnecting a plurality of refrigerant line segments and a plurality of valves to provide the refrigerant line system that provides a first refrigerant loop for the first mode of operation; a second refrigerant loop for the second mode of operation; and a third refrigerant loop for the third mode of operation. The refrigerant line system may be similar to the refrigerant line system  110  described above with reference to  FIGS. 1, 6 and 7 . 
     The method may further comprise connecting one or more valves of the refrigerant line system to a control module (such as the example control module  160  shown in  FIGS. 8 and 9 ). 
       FIG. 13  is a flowchart of a method according to yet another embodiment. The method of  FIG. 13  may, for example, be implemented by a control module (e.g. control module  160  of  FIGS. 8 and 9 ) of a heating and cooling apparatus (e.g. apparatus  100  in  FIGS. 1, 6 and 7 ) as described herein or by a remote computer control system connected to the apparatus. The apparatus in this method comprises a first heat exchanger; a second heat exchanger; a third heat exchanger; a compressor; a first fluid line for a first fluid coupled to the first heat exchanger; a second fluid line for a second fluid coupled to the second heat exchanger; and a refrigerant line system coupled to the first, second and third heat exchangers and configurable for selectively directing refrigerant fluid as described below. In this example, the first fluid is a cooling fluid, the second fluid is a heating fluid, and the third fluid is a source fluid. 
     At block  1302 , a selected mode of operation for the apparatus is determined. Determining the selected mode of operation may comprise receiving an indication of the selected mode of operation as user input (e.g. receiving the input via a user interface). Alternatively, determining the selected mode of operation may comprise selecting the mode of operation as a function of received data (e.g. temperature and/or pressure date). As yet another example, the determining may comprise receiving a signal from a remote computer system that comprises an indication of the mode of operation. Other methods of determining the selected mode of operation are also possible. The method then continues at block  1304 . 
     In some embodiments, the method further comprises, after block  1302 , determining whether the selected mode of operation is different than a current mode of operation. If not, the method may end. If so, the method may continue to block  1304 . 
     If the selected mode of operation is a first mode of operation (“mode  1 ” branch, block  1304 ), then at block  1306  the refrigerant line system is configured to direct refrigerant fluid through the first and third heat exchangers and the compressor, to cool the first fluid. Optionally, the step of block  1306  further comprises starting flow of the first fluid in the first fluid line and/or starting flow of the third fluid in the third fluid line. The step may further comprise stopping flow of the second fluid in the second fluid line. 
     If the mode of operation is a second mode of operation (“mode  2 ” branch, block  1304 ), then at block  1308  the refrigerant line system is configured to direct refrigerant fluid through the second and third heat exchangers and the compressor, to heat the second fluid. Optionally, the step of block  1308  further comprises starting flow of the second fluid in the second fluid line and/or starting flow of the third fluid in the third fluid line. The step may further comprise stopping flow of the first fluid in the first fluid line. 
     If the mode of operation is a third mode of operation (“mode  3 ” branch, block  1304 ), then at block  1310  the refrigerant line system is configured to direct refrigerant fluid through the first and second heat exchangers and the compressor, to both cool the first fluid and heat the second fluid. Optionally, the step of block  1310  further comprises starting flow of the first fluid in the first fluid line and/or starting flow of the second fluid in the second fluid line. The step may further comprise stopping flow of the third fluid in the third fluid line. 
     The method may also comprise, for a fourth, standby mode of operation, in which the flow in each of the first, second and third fluid lines is stopped as well as the flow of the refrigerant in the refrigerant line system. 
     Configuring the refrigerant line system may comprise controlling one or more valves in the refrigerant line system (such as the refrigerant line system  110  of  FIGS. 1, 6 and 7 , for example) to provide different refrigerant loops for the first, second and third modes of operation. 
     It is to be understood that a combination of more than one of the approaches described above may be implemented. Embodiments are not limited to any particular one or more of the approaches, methods or apparatuses disclosed herein. One skilled in the art will appreciate that variations, alterations of the embodiments described herein may be made in various implementations without departing from the scope of the claims.