MX2007001462A - Heat pump system with auxiliary water heating - Google Patents

Abstract

A heat pump system (10) includes a compressor (20), a reversing valve (30), an outdoor heat exchanger (40) and an indoor heat exchanger (50) coupled via refrigerant lines (35, 45, 55) in a refrigeration circuit, and a refrigerant-to-water heat exchanger (60). In the air cooling/water heating mode, the air heating/water heating mode, and the water heating only mode, water from a water reservoir (64) (i.e., a storage tank or swimming pool) passes through the refrigerant-to-water heat exchanger (60) in heat exchange relationship with refrigerant passing through line (35). A refrigerant reservoir (70) may be provided for refrigerant charge control. A refrigerant line (71) couples reservoir (70) to the refrigeration circuit intermediate the outdoor and indoor heat exchangers (40, 50) for directing liquid refrigerant into the reservoir (70). A refrigerant line (73) couples the refrigeration circuit upstream of the suction inlet to the compressor (20) for returning refrigerant to the refrigeration circuit. A controller (100) controls flow into and from the refrigerant reservoir (70) through selective opening and closing of control valves (72, 74) in lines (71, 73), respectively.

Description

HEAT PUMP SYSTEM WITH AUXILIARY WATER HEATING DESCRIPTION OF THE INVENTION This invention generally relates to heat pump systems and, more particularly to heat pump systems that include auxiliary liquid heating, which include for example heating water to swimming pools, domestic water systems and similar. Reversible heat pumps are well known in the art and are commonly used to cool and heat a climate-controlled comfort zone with a residence or a building. A conventional heat pump includes a compressor, a suction accumulator, an inversion valve, an external heat exchanger with an associated fan, an internal heat exchanger with an associated fan, an expansion valve operatively associated with the external heat exchanger and a second temperature valve. expansion operatively associated with the internal heat exchanger. The aforementioned components are typically arranged in a closed coolant circuit pump system employing the well-known Carnot vapor compression cycle. When operating in the cooling mode, the excess heat absorbed by the refrigerant when passing through the internal heat exchanger is rejected to the environment as the refrigerant passes through the external heat exchanger. i It is well known in the art that an additional water-to-water heat exchanger can be added to a heat pump system to absorb this excess heat for the purpose of heating water, rather than simply rejecting excess heat to the environment. In addition, heat pumps often have unused heating capacity when operating in the heating medium to heat the climate controlled zone. For example, each of U.S. Patent Nos. 3,188,829; 4,098,092, 4,492,092 and 5,184,472 disclose a heat pump system that includes an auxiliary hot water heat exchanger. However, these systems do not include any device to control the refrigerant charge within the refrigerant circuit. Therefore, while they are functional, these systems can not be optimally efficient in all modes of operation. In heat pump systems, the external heat exchanger and the internal heat exchanger each operate as an evaporator, condenser or subcooler, depending on the mode and point of operation. As such, condensation may occur in any of the heat exchangers, and the suction line may be filled with refrigerant in a gaseous or liquid state. As a consequence, the amount of refrigerant charge of the system required in each mode of operation to ensure a Operation within an acceptable efficacy coverage will be different for each mode. US Patent 4,528,822 discloses a heat pump system that includes an additional liquid refrigerant heat exchanger to heat the liquid using heat that can otherwise be rejected into the environment. The system can be operated in four independent modes of operation: space heating, slow cooling, liquid heating and space cooling simultaneously with the heating of the liquid. In the liquid-only heating mode, the internal heat exchanger fan shuts off while in the space cooling and liquid heating mode, the external heat exchanger fan shuts off. A refrigerant charge tank is provided in which the liquid refrigerant is drained by gravity from the liquid refrigerant heat exchanger during the liquid heating only mode and the simultaneous slow cooling and liquid heating mode. However, with a control procedure they are described to effectively control the refrigerant charge in the refrigerant circuit in all modes of operation. In addition, no mode of space heating and simultaneous liquid heating is described. Therefore, it is desirable that the system provide including active refrigerant charge control in all modes of operation whereby the pump system can effectively operate in an air-only cooling mode, an air-cooling and liquid-heating mode, an air-only mode, a mode of heating of air and heating of liquid, and a mode of heating only of liquid. In one aspect, it is an object of the invention to provide a heat pump system having a liquid heating capacity and an improved refrigerant charge control. In one aspect it is an object of the invention to provide a heat pump system having a liquid heating capacity and refrigerant charge control in all modes of operation. In one embodiment of the invention, a heat pump system includes a refrigerant compressor, having a suction port and a discharge port; a selectively positioned four-lumen reversing valve having a first position for coupling the first port and the second port in fluid flow communication and the third port and the fourth port in fluid flow communication, and a second one position for coupling the first port and the third port in fluid flow communication and the second port and the fourth port in fluid flow communication; and a refrigerant circuit provides a closed-loop refrigerant circulation flow path. The refrigerant circuit has a first refrigerant line that establishes a flow path between the discharge port of the compressor and the first port of the reversing valve, a second line of refrigerant that establishes a flow path between the second port of the refrigerant. reversing valve and the third port of the reversing valve, and a third refrigerant line that establishes a flow path between the fourth port of the reversing valve and the suction port of the compressor. An external heat exchanger is arranged in operative association with the second refrigerant line and is adapted to pass the refrigerant which passes through the second refrigerant line in heat exchange relationship with the ambient air. An internal heat exchanger is arranged in operative association with the second refrigerant line and is adapted to pass the refrigerant passing through the second refrigerant line in heat exchange relationship with the air from the comfort zone. The internal heat exchanger is disposed downstream of the external exchanger with respect to the flow of refrigerant in the air cooling mode and upstream of the external heat exchanger with respect to the flow of refrigerant through the second refrigerant line in the air heating mode. A liquid refrigerant heat exchanger is arranged in operative association with the first refrigerant line and is adapted to pass the refrigerant which passes through the first refrigerant line in heat exchange relationship with a liquid. A coolant reservoir having an inlet is provided via a fourth refrigerant line in fluid flow communication with the second refrigerant line at an intermediate location to the external heat exchanger and the internal heat exchanger and an output coupled through a Fifth refrigerant line in fluid flow communication with the third refrigerant line. In another embodiment of the invention, a heat pump system includes a refrigerant compressor having a suction port and a discharge port; a first four-port valve that can be selectively positioned having a first position for coupling the first port and the second port in fluid flow communication and the third port and the fourth port in fluid flow communication, and a second position for coupling the first port and the third port in fluid flow communication and the second port and the fourth port in fluid flow communication; and a refrigerant circuit that provides a closed-loop refrigerant circulation flow path. The refrigerant circuit has a first refrigerant line that establishes a flow path between the discharge port of the compressor and the first port of the reversing valve, a second line of refrigerant that establishes a flow path between the second port of the refrigerant. reversing valve and the third port of the reversing valve, and a third refrigerant line that establishes a flow path between the fourth port of the reversing valve and the suction port of the compressor. An external heat exchanger is arranged in operative association with the second refrigerant line and is adapted to pass the refrigerant passing through the second refrigerant line in heat exchange relationship with the ambient air. An internal heat exchanger is arranged in operative association with the second refrigerant line and is adapted to pass to the refrigerant passing through the second line of the refrigerant in heat exchange relationship with the air from the comfort zone. The internal heat exchanger is arranged downstream of the external heat exchanger with respect to the flow of refrigerant in the air cooling mode and upstream of the external heat exchanger with respect to the flow of refrigerant through the second line of refrigerant in the air heating mode. A liquid refrigerant heat exchanger is arranged in operative association with the first refrigerant line and is adapted to pass the refrigerant which passes through the first line of the refrigerant in heat exchange relationship with a liquid. In this embodiment, a second four-port valve that can be selectively positioned is provided having a first position for coupling the first port and the second port in fluid flow communication and the third port and the fourth port in flow communication fluid and a second position for coupling the first port and the third port in fluid flow communication and the second port and the fourth port in fluid flow communication. This second four-port valve is arranged in the second refrigerant line with the first port in flow communication with the internal heat exchanger and the second port in flow communication with the third port of the first four-port valve. A coolant reservoir is provided having an inlet coupled through a fourth line of refrigerant in fluid flow communication with the second refrigerant line at an intermediate location to the external heat exchanger and the internal heat exchanger and an output coupled through the a fifth line of refrigerant in flow communication fluid with the third refrigerant line. A branch purge flow circuit is included that has a first purge line coupled in flow communication between the fifth line of refrigerant and the third port of the second valve that can be selectively placed and a second purge line coupled in communication of flow between the internal heat exchanger and the fourth port of the second valve that can be selectively placed. In any of the above-mentioned embodiments, it is particularly advantageous to include a first flow control valve having an open position and a closed position being arranged in the fourth line of refrigerant to control the flow of refrigerant from the second refrigerant line to the coolant reservoir inlet; a second flow control valve having an open position and a closed position is arranged in the fifth line of refrigerant to control the flow refrigerant between the outlet of the refrigerant tank and the third line of the refrigerant, and a controller selectively controls the respective positioning of the first and second flow control valves between their respective open and closed positions to selectively control the refrigerant charge within the refrigerant circuit. The first and second flow control valves can also have at least one position partially open and may comprise solenoid valves modulated by pulse amplitude. The controller may further be operative to selectively modulate the respective placement of the flow control valves between their open, partially open and closed positions. In a further embodiment, a liquid level sensor is provided to detect the level of liquid refrigerant in the refrigerant tank and to provide a signal to the controller indicative of the level of liquid inside the refrigerant tank. In response to the liquid level signal, the controller will selectively control the respective positioning of the first and second flow control valves to selectively control the refrigerant charge within the refrigerant circuit. A first expansion valve operatively associated with the internal heat exchanger and the second expansion valve operatively associated with the external heat exchanger can be arranged in the second refrigerant line, with the first expansion valve arranged intermediate to the external heat exchanger and the location of the inlet of the refrigerant tank is coupled in fluid flow communication with the second refrigerant line, and the second expansion valve arranged intermediate to the internal heat exchanger and the Location of the coolant reservoir inlet is coupled in fluid flow communication with the second refrigerant line. A first expansion valve branch line operatively associated with the second refrigerant line provides the bypass of the refrigerant which passes through the second refrigerant line in one direction from the external heat exchanger to the internal heat exchanger around the first expansion valve and through the second expansion valve. A second expansion valve branch line operatively associated with the second refrigerant line provides the bypass of the refrigerant which passes through the second refrigerant line in one direction from the internal heat exchanger to the external heat exchanger around the second expansion valve and through the first expansion valve. BRIEF DESCRIPTION OF THE DRAWINGS For a further understanding of these and the objects of the invention, reference will now be made to the following detailed description of the invention which will be read in conjunction with the accompanying drawings, wherein: Figure 1 is a schematic diagram that illustrates a first embodiment of the heat pump system of the invention illustrating operation in a single air cooling mode; Figure 2 is a schematic diagram illustrating a first embodiment of the heat pump system of the invention, illustrating the operation in the indoor air cooling mode with water heating; Figure 3 is a schematic diagram illustrating a first embodiment of the heat pump system of the invention illustrating the operation in the intimate air cooling only mode. Figure 4 is a schematic diagram illustrating a first embodiment of the heat of the invention illustrating the operation in an internal air cooling mode with water heating; Figure 5 is a schematic diagram illustrating a first embodiment of the heat pump system of the invention illustrating the operation in the water-only heating mode; Figure 6 is a schematic diagram illustrating a second embodiment of a heat pump system of the invention illustrating operation in an air cooling mode; Figure 7 is a schematic diagram illustrating a second embodiment of the heat pump system of the invention illustrating operation in a first mode of air heating; Figure 8 is a schematic diagram illustrating a second embodiment of the heat pump system of the invention illustrating the operation in a second mode of air heating; Figure 9 is a schematic diagram illustrating one embodiment of a control system arranged for the heat pump system of the invention; Figure 10 is a block diagram illustrating a first embodiment of a refrigerant charge adjustment procedure at the start in a new mode of operation; Figure 11 is a block diagram illustrating a second embodiment of a refrigerant charge adjustment procedure at the start in a new mode of operation; Figure 12 is a block diagram illustrating a third embodiment of a refrigerant charge adjustment procedure at the start in a new mode of operation; Figure 13 is a block diagram illustrating a discharge temperature limit control method for adjusting the post-start of refrigerant charge; and Figure 14 is a block diagram illustrating a load control procedure for adjusting the postinicio of the refrigerant charge. The refrigerant heat pump system 10, represented in a first embodiment in Figures 1-5 and a second embodiment in Figures 6-8, not only providesheating or cooling of air in a comfort region, for example in an internal zone located inside a building (not shown), but also auxiliary water heating. The system includes a compressor 20, a suction accumulator 22, a reversing valve 30, an external heat exchanger 40 and associated fan 42 located on the outside of a building in heat transfer relationship with the surrounding environment, an internal heat exchanger 50 and associated fan 52 located in the comfort zone, a first expansion valve 44 operatively associated with the external heat exchanger 40 and a second expansion valve 54 operatively associated with the internal heat exchanger 50. A refrigerant circuit including refrigerant lines 35, 45 and 55 provides a closed-loop refrigerant flow path that couples these components in a conventional manner for a heat pump system employing a well-known Carnot vapor compression cycle. . Additionally, the system 10 includes a water-to-water heat exchanger 60 where the refrigerant passes in heat exchange relationship with the water to be heated. The water to be heated is pumped by a circulation pump 62 via the line 65 of water circulation from a water reservoir 64, for example a hot water storage tank or a swimming pool, through of the heat exchanger 60 and again to the reservoir 64. The compressor 20, which may comprise a rotary compressor, a scroll compressor, an oscillating compressor, a screw compressor or any other type of compressor, has a suction inlet for receiving the refrigerant from the suction accumulator 22 and an outlet for discharging the compressed refrigerant. The reversing valve 30 may comprise a selectively positionable two-position four-port valve having a first port 30-1, a second port 30-2, a third port 30-3 and a fourth port 30-4 . The reversing valve 30 may be placed in a first position for coupling the first port and the second port in fluid flow communication and for simultaneously coupling the third port and the fourth port in fluid flow communication. The reversing valve 30 may be placed in a second position for coupling the first port and the third port in fluid flow communication and for simultaneously coupling the second port and the fourth port in fluid flow communication. Advantageously, the respective port-to-port connections established in the first and second positions are achieved internally within the valve 30. The outlet 28 of the compressor 20 is connected in fluid flow communication via the line of coolant to the first port 30-1 of the reversing valve 30. The second port 30-2 of the reversing valve 30 is externally coupled from the valve in refrigerant flow communication to the third port 30-3 of the reversing valve 30 via the refrigerant line 45. The fourth port 30-4 of the reversing valve 30 is coupled in refrigerant flow communication to the suction inlet 26 of the compressor 20. The external heat exchanger 40 and the internal heat exchanger 50 are operatively arranged in the refrigerant line 45. The external heat exchanger 50 is connected in fluid flow communication via the section 45A of the refrigerant line 45 to the second port 30-2 of the reversing valve 30. The internal heat exchanger 50 is connected in fluid flow communication to the third port 30-3 of the reversing valve 30 via the section 45C of the refrigerant line 45. The section 45B of the refrigerant line 45 couples the external heat exchanger 40 and the internal heat exchanger 50 in refrigerant flow communication. A suction accumulator 22 can be arranged in the refrigerant line 55 on the suction side of the compressor 20, which has its inlet connected in refrigerant flow communication to the fourth port 30-4 of the reversing valve 30 through the section 55A of the line 55 of refrigerant and having its outlet connected in refrigerant flow communication to the suction inlet of the compressor 20 through the section 55B of the refrigerant line 55. Therefore, the refrigerant lines 35, 45 and 55 together couple the compressor 20, the external heat exchanger 40 and the internal heat exchanger 50 in refrigerant flow communication, thereby creating a closed loop for the circulation of refrigerant flow to through the heat pump system 10. The first and second expansion valves 44 and 54 are disposed in the section 45B of the refrigerant line 45. In the embodiments shown in the drawings, the first expansion valve 44 is operatively associated with the external heat exchanger 40 and the second expansion valve 54 is operatively associated with the internal heat exchanger 50. Each of the expansion valves 44 and 54 is provided with a branch line equipped with a regulating valve that allows flow in only one direction. The regulating valve 46 on the bypass line 43 associated with the expansion valve 44 of the external heat exchanger passes the refrigerant flowing from the external heat exchanger 40 to the internal heat exchanger 50, thereby bypassing the expansion valve 44 of the external heat exchanger and passing refrigerant to the expansion valve 54 of internal heat exchanger. Conversely, the regulating valve 56 in the bypass line 53 associated with the expansion valve 54 of the internal heat exchanger passes the refrigerant flowing from the internal heat exchanger 50 to the external heat exchanger 40, thereby bypassing the expansion valve 54 of the internal heat exchanger and passing the refrigerant to the expansion valve 44 of the external heat exchanger. Additionally, the water-to-water heat exchanger 60 is operatively associated with the refrigerant line 35 whereby the refrigerant flowing through the refrigerant line 35 passes in heat exchange relationship with the water passing through the line 65 of water circulation. In the embodiment of the heat pump system 10 shown in Figures 6, 7 and 8, the system includes, in addition to the previously mentioned components, a suction line bypass valve 90 having a first position and a second position, a bypass flow control valve 92 having an open valve state and a closed valve state, such as, for example, a solenoid valve, a bypass line 93, a bypass line 95 and a regulating valve 94. The suction line bypass valve 90, which advantageously is a four-port valve, of two positions that can be selectively placed, is disposed in the circuit of intermediate cooling to the internal heat exchanger 50 and the reversing valve 30. The refrigerant line 51A extends between the internal heat exchanger 50 and a first port 90-1 of the suction line purge valve 90, and the refrigerant line 51B extends between the third port 30-3 of the valve 30 of and a second port 90-2 of the suction line purge valve 90, whereby lines 51A and 51B will be connected in refrigerant flow communication whenever the suction line purge flow valve 90 is in. Your first position The refrigerant line 93 extends in flow communication between the refrigerant line 73 and a third port 90-3 of the suction line branch valve 90. The refrigerant line 95 extends in flow communication between a fourth port 90-4 of the suction line bypass valve 90 and the refrigerant line 51A, which opens to the refrigerant line 51A at an intermediate location to the heat exchanger 50 and the bypass flow control valve 92, whereby lines 93 and 95 will also be connected in refrigerant flow communication provided that the suction line purge flow valve 90 is in its first position. The bypass flow control valve 92 is arranged in the refrigerant line 51A and is operative for closing line 51A of refrigerant to flow through it when in its closed valve state and to open refrigerant line 51A to flow through it when in its open valve state. The regulating valve 94 is arranged in the refrigerant line 95 to allow the refrigerant to flow through the refrigeration line 95 from the suction line bypass valve 90 to the refrigerant line 51A, but to block the flow of refrigerant through the cooling line 95 from the refrigeration line 51A to the suction line bypass valve 90. Provided that the suction line bypass valve 90 is in its second position, lines 51A and 93 will be coupled in refrigerant flow communication, and lines 51B and 95 will also be coupled in refrigerant flow communication through the Suction Line Bypass Valve 90 In the system of the invention, the heat pump operates not only to heat or cool air in a comfort region, but also to heat water on demand. Therefore, the system must operate effectively in an air-only cooling mode, an air-cooling and water-heating mode, an air-only mode, an air-heating mode and water heating, and a water heating mode only. Since the external heat exchanger 40 and the heat exchanger 50 Inner ports operate as an evaporator, condenser or subcooler, depending on the mode and point of operation, condensation can occur in one or two heat exchangers, and the suction line can be filled with the refrigerant in a gaseous or liquid state. As a consequence, the amount of refrigerant charge of the system required in each mode to ensure an operation within an envelope of acceptable efficiency will be different for each mode. When water heating is not required, the amount of refrigerant charge required will also be affected by the amount of heat exchange due to the occurrence of the thermal siphon movement in the water-to-water heat exchanger 60. Accordingly, the system 10 further includes a refrigerant storage tank 70, called a cargo tank, which has an inlet connected in fluid flow communication with the refrigerant line 45 via the refrigerant line 71 and an outlet connected in communication. fluid flow with the refrigerant line 71 and an outlet connected in fluid flow communication with the refrigerant line 55 via the refrigerant line 73, a first flow control valve 72 disposed in the refrigerant line 71, and a second flow control valve 74 disposed in the coolant line 73. Each of the first and second valves 72 and 74 flow control has an open position and a closed position so that the flow through them can be controlled selectively so that the refrigerant charge within the refrigerant circuit can be actively controlled. Advantageously, each of the first and second flow control valves 72 and 74 may also have at least a partially open position and may be a pulse amplitude modulated solenoid valve. Additionally, a liquid level meter 80, such as for example a transducer, can be arranged in the cargo tank 70 to monitor the level of refrigerant inside the cargo tank. Referring now to Figure 9, a controller 100 of the system, advantageously a microprocessor, controls the operation of the water pump 62, the compressor 20, the reversing valve 30, and other components of the heat pump, such as the fan 42 of the external heat exchanger and the fan 52 of the internal heat exchanger, in response to the cooling or heating demand of the comfort region in a conventional manner and / or the water heating demand. In the embodiment shown in Figures 6, 7 and 8, the system controller also controls the operation of the suction line bypass valve 90 and the bypass flow control valve 92. In addition, the system controller 100 controls the opening and closing of the flow control valves 72 and 74 to adjust to the refrigerant charge to coordinate with the system requirements for the various modes of operation. The system controller 100 receives input signals indicative of various operational parameters of the system from a plurality of sensors, including without limitation, a suction temperature sensor 81, a suction pressure sensor 83, a discharge temperature sensor 85. , a discharge pressure sensor 87, a water temperature sensor 89, an external heat exchanger coolant temperature sensor 82, an internal heat exchanger coolant temperature sensor 84, and a coolant temperature sensor 86 arranged in association operative with the section 45B of the refrigerant line 45 at a location between the expansion valves 44 and 54. The suction temperature sensor 81 and the suction pressure sensor 83 are arranged in operative association with the refrigerant lines 55 near the suction inlet to the compressor 20 as in conventional practice to detect the temperature and pressure of the refrigerant, respectively , in the suction inlet of the compressor and to pass respective signals indicative thereof to the system controller 100. The discharge temperature sensor 85 and the discharge pressure sensor 87 are arranged in operative association with the refrigerant line 35 near the discharge outlet to the compressor 20 as in conventional practice to detect the temperature and pressure of the refrigerant, respectively at the discharge outlet of the compressor and to pass respective signals indicative thereof to the controller 100 of the system. The water temperature sensor 89 is arranged in operative association with the water reservoir 64 to detect the temperature of the water therein and to pass a signal indicative of the detected water temperature to the controller 100 of the system. The temperature sensor 82 is arranged in operative association with the external heat exchanger 40 at an appropriate location to measure the refrigerant phase change temperature of the refrigerant passing through it when the external heat exchanger is operating and to send a signal indicative of this temperature detected to the system controller 100 to control the operation of the expansion valve 44. Similarly, the temperature sensor 84 is arranged in an operative operation with the internal heat exchanger 50 in an appropriate location to measure the change temperature of the refrigerant phase of the refrigerant passing through it when the internal heat exchanger is operating and for sending a signal indicative of that detected temperature to the system controller 100, to control the operation of the valve 54 of expansion. The system controller 100 determines the degree of superheating of the refrigerant temperature detected by any of the sensors 82 and 84 and is associated with the heat exchanger that is acting as an evaporator in the current mode of operation. The refrigerant temperature sensor 86 operatively associated with the refrigerant line 45 detects the temperature of the refrigerant at a location between the expansion valves 44 and 54 and passes a signal indicative of the detected temperature to the system controller 100. The system controller determines the degree of subcooling present of the sensed temperature received in the temperature sensor 86. Referring now to Figure 1, in the indoor air cooling only mode, in response to a cooling demand, the system controller 100 activates the compressor 20, the fan 42 of the external heat exchanger and the fan 52 of the internal heat exchanger. The high-pressure superheated refrigerant of the compressor 20 passes through the refrigerant line 35 to the reversing valve 30 where the refrigerant is directed to and through the section 45A of the refrigerant line 45 to the external heat exchanger 40, which in the Air cooling mode works like a condenser. With the external heat exchanger fan 42 operating, the ambient air flows through the external heat exchanger 40 in heat exchange relationship with the refrigerant passing through it, whereby the high pressure refrigerant condenses in a liquid and is subcooled. The high pressure liquid refrigerant passes from the external heat exchanger 40 through the section 45B of the refrigerant line 45 to the internal heat exchanger 50, which in the air cooling mode functions as an evaporator. Upon passing through the section 45B of the refrigerant line 45, the high pressure liquid refrigerant derives the expansion valve 44 through the bypass line 43 and the regulating valve 46 and thus passes through the valve 54 of expansion where the high pressure liquid refrigerant is extended to a lower pressure, thereby further cooling the refrigerant before the refrigerant enters the internal heat exchanger 50. When the refrigerant crosses the internal heat exchanger, the refrigerant evaporates. With the fan 52 of the internal heat exchanger operating the internal air passes through the internal heat exchanger 50 in heat exchange relationship with the refrigerant thereby evaporating the refrigerant and cooling the internal air. The refrigerant passes from the internal heat exchanger through the section 45C of the refrigerant line 45 to the reversing valve 30 and it is directed through section 55A of refrigerant line 55 to suction accumulator 22 before returning to compressor 20 through section 55B of refrigerant line 55 which is connected to suction inlet of compressor 20 Upon passing through the refrigerant line 35, the refrigerant passes through the heat exchanger 60 where the refrigerant passes in relation to heat exchange with the water in the line 65. In the air-only cooling mode, the amount Heat exchanged from the coolant to the water is small when the water pump 62 is turned off. Therefore, only a small amount of water flows through the heat exchanger 60, the flow of water through the line 65 is driven by a thermal siphon movement effect. However, even with the water flow being small in the air-cooling mode only, eventually the heat exchange may be sufficient to de-superheat the refrigerant. Referring now to Figure 2, when there is a demand for water heating while the heat pump is in the internal air cooling mode, the controller 100 of the system activates the water pump 60 and the water is pumped through the line 65 of water from the storage tank 64 through the heat exchanger 60 in heat exchange relationship with the refrigerant superheated high pressure flowing through line 35 of refrigerant. When the refrigerant passes through the heat exchanger 60, the refrigerant is condensed and subcooled when it leaves the heat to heat the water flowing through the heat exchanger 60 in heat exchange relationship with the refrigerant. Since in this air cooling mode with water heating, the refrigerant which passes through the section 45A of the refrigerant line 45 to the external heat exchanger 40 has already been condensed and subcooled when it passes through the heat exchanger 60 in When exchanging heat with water, there is no need for any significant additional cooling in the external heat exchanger. In addition, additional subcooling can decrease the water heating capacity. Therefore, in this internal air cooling mode with water heating, the system controller 100 shuts off the fan 42 of the external heat exchanger in such a way that ambient air is not passed through the external heat exchanger 40, thereby minimizing the amount of heat loss experienced by the refrigerant passing through it in such a way that the refrigerant experiences only a small relative amount of additional subcooling. However, when the temperature of the water in the reservoir 64 reaches its set point, it may be desirable to activate the ventilator 52 to improve the operating efficiency of the system. The condensed and subcooled liquid refrigerant leaving the external heat exchanger 40 passes through the section 45B of the refrigerant line 45 to the internal heat exchanger 50, which in the air cooling mode functions as an evaporator. Upon passing through the refrigerant line 45B, the high pressure liquid refrigerant derives the expansion valve 44 through the bypass line 43 and the regulating valve 46, and therefore passes through the expansion valve 54 wherein the high pressure liquid refrigerant is extended to a lower pressure, thereby cooling the refrigerant further before the refrigerant enters the internal heat exchanger 50. When the refrigerant crosses the internal heat exchanger, the refrigerant evaporates. With the fan 52 of the internal heat exchanger operating, the internal air passes through the internal heat exchanger 50 in heat exchange relationship with the refrigerant thereby evaporating the refrigerant and cooling the internal air. The refrigerant passes from the internal heat exchanger through the section 45C of the refrigerant line 45 to the reversing valve 30 and is directed through the section 55A of the refrigerant line 55 to the suction accumulator 22 before returning to compressor 20 through section 55B of the refrigerant line 55 which is connected to the suction inlet of the compressor 20. Referring now to Figure 3, in the mode of internal air heating only, in response to a heating demand, the controller 100 of the active system the compressor 20, the fan 42 of the external heat exchanger and the fan 52 of the internal heat exchanger. The superheated high pressure refrigerant from the compressor 20 passes through the refrigerant line 35 to the reversing valve 30 where the refrigerant is directed to and through the section 45C of the refrigerant line 45 to the internal heat exchanger 50, which in The air heating mode works like a condenser. With the fan 52 of the internal heat exchanger operating, the internal air passes through the internal heat exchanger 50 in relation to the heat exchange with the refrigerant passing through it, whereby the high pressure refrigerant is condensed in a liquid and Subcool 50 and the internal air are heated. The high pressure liquid refrigerant passes from the internal heat exchanger 50 through the section 45B of the refrigerant line 45 to the external heat exchanger 40, which in the air heating mode functions as an evaporator. When passing through section 45B of line 45 of refrigerant, the liquid refrigerant high pressure drifts the expansion valve 54 through the branch line 53 and the regulating valve 56 and therefore passes through the expansion valve 44 where the high pressure liquid refrigerant is extended to a lower pressure, in this way by further cooling the refrigerant before the refrigerant enters the external heat exchanger 40. With the fan 42 of the external heat exchanger operating, the ambient air passes through the external heat exchanger and when the refrigerant crosses the external heat exchanger the refrigerant evaporates. The refrigerant passes from the external heat exchanger 40 through the section 45A of the refrigerant line 45 to the reversing valve 30 and is directed through the section 55A of the refrigerant line 55 to the suction accumulator 22 before returning to the compressor 20 through the section 55B of the refrigerant line 55 which is connected to the compressor suction inlet 20. When passing through the refrigerant line 35, the refrigerant passes through the heat exchanger 60 where the refrigerant passes. in heat exchange relationship with the water in line 65. In the air cooling only mode, the amount of heat exchanged from the refrigerant to the water is small when the water pump 62 is turned off. Therefore, only a small amount of water flows through the heat exchanger 60, the flow of water through the line 65 is driven by a thermal siphon movement effect. However, even with the water flow being small in the air-only cooling mode, eventually the heat exchange may be sufficient to de-superheat the refrigerant. Referring now to Figure 4, when there is a demand for water heating while the heat pump is in the internal air heating mode, the system controller 100 activates the water pump 60 and the water is pumped through the line 65 of water from the storage tank 64 through the heat exchanger 60 in heat exchange relationship with the superheated high pressure steam refrigerant flowing through the refrigerant line 23. When the refrigerant passes through the heat exchanger 60, the refrigerant is partially condensed or condensed and partially subcooled, depending mainly on the water temperature and the internal air temperature, as it leaves the heat to heat the water flowing through the water. heat exchanger 60 in heat exchange relationship with the refrigerant. In this mode of air heating with water heating, although the refrigerant passes through the section 45C of the refrigerant line 45 to the internal heat exchanger 50 it has already partially condensed, or condensed and condensed. partially subcooling, when it passes through the heat exchanger 60 in heat exchange relationship with the water, there is still a need to heat the internal air. Therefore, in this internal air heating mode with water heating, the controller 100 of the system activates the fan 52 of the internal heat exchanger in such a way that the internal air is passed through the internal heat exchanger 50 in heat exchange relation. with the refrigerant that passes through it, so it heats the internal air that is provided to the comfort zone and also completes the condensation and / or subcooling of the refrigerant. The high pressure subcooled liquid refrigerant passing from the internal heat exchanger 50 passes through the section 45B of the refrigerant line 45 to the external heat exchanger 40, which in the air heating mode functions as an evaporator. Upon passing through section 45B of refrigerant line 45, the high pressure liquid refrigerant derives expansion valve 54 through the bypass line 53 and regulating valve 56 and therefore passes through the expansion valve 44 where the high pressure liquid refrigerant is extended to a lower pressure, thereby further cooling the refrigerant before the refrigerant enters the external heat exchanger 40. With the fan 42 of the external heat exchanger operating, the ambient air passes through the external heat exchanger and when the refrigerant crosses the external heat exchanger, the refrigerant evaporates. The refrigerant passes from the external heat exchanger 40 through the section 45A of the refrigerant line 45 to the reversing valve 30 and is directed through the section 55A of the refrigerant line 55 to the suction accumulator 22 before returning to the compressor 20 through the section 55B of the refrigerant line 55 which is connected to the suction inlet of the compressor 20. Referring now to Figure 5, when there is a demand for water heating while the heat pump is off , which is not in the internal air cooling or heating mode, the system controller 100 activates the water pump 60, the compressor 20, and the fan 42 of the external heat exchanger, but not the fan 52 of the internal heat exchanger. With the pump 60 turned on, the water is pumped via the water line 65 from the storage tank 64 through the heat exchanger 60 in heat exchange relationship with the superheated high pressure steam refrigerant flowing through the line 35. of refrigerant. When the refrigerant passes through the heat exchanger 60, the refrigerant condenses and subcooling when it leaves the heat to heat the refrigerant. water flowing through the heat exchanger 60 in heat exchange relationship with the refrigerant. The refrigerant leaving the heat exchanger 60 continues through line 35 to the reversing valve 30 which directs the refrigerant through the section 45C of the refrigerant line 45 to the internal heat exchanger 50. In this water-only heating mode, the internal heat exchanger fan 52 is turned off so that the internal air is not passed through the internal heat exchanger, since it does not. there is a demand for cooling or heating of the internal air in the comfort zone. Therefore, no additional subcooling of the refrigerant occurs in the internal heat exchanger in the water-only heating mode. Having crossed the internal heat exchanger 50 without additional subcooling, the high pressure subcooled liquid refrigerant passes through the section 45B of the refrigerant line 45 to the external heat exchanger 40, which in the air heating mode functions as an evaporator. Passing through the section 45B of the refrigerant line 45, the high pressure liquid refrigerant derives the expansion valve 54 through the bypass line 53 and the regulating valve 56 and therefore passes through the valve 44 expansion where the high pressure liquid refrigerant is extended to a lower pressure, further cooling the refrigerant before the refrigerant enters the external heat exchanger 40. With the fan 42 of the external heat exchanger operating, the ambient air passes through the external heat exchanger and when the refrigerant crosses the external heat exchanger, the refrigerant evaporates. The refrigerant passes from the external heat exchanger 40 through the section 45A of the refrigerant line 45 to the reversing valve 30 and is directed through the section 55A of the refrigerant line 55 to the suction accumulator 22 before returning to the compressor 20 through the section 55B of the refrigerant line 55 which is connected to the suction inlet of the compressor 20. Referring now to Figure 6, representing the second mode of the heat pump system operating in the mode of air cooling only, the suction line vent valve 90 is placed in a first position as illustrated in Figure 6 and the bypass flow control valve 92 in its open position. In this way, the refrigerant line 51A and 51B is connected in flow communication by the suction line bypass valve 90 and the refrigerant flows in the same route through the various components of the refrigerant circuit as described in FIG. the above with respect to Figure 1. Additionally, lines 93 and 95 are also they connect in flow communication through the suction line bypass valve 90, whereby the refrigerant in the charge tank 70 can enter the refrigerant circuit if the solenoid valve 74 in line 73 is opened by the system controller. The flow to line 95 of line 51A is blocked by regulating valve 94. In the air cooling and water heating mode, the suction line bleed valve 90 is again placed in its first position as illustrated in Figure 6 and the bypass flow control valve 92 is in its open position . In this way, the refrigerant line 51A and 51B is again connected in flow communication by the suction line bypass valve 90 and the refrigerant flows in the same route through the various components of the refrigerant circuit as described in the above with respect to Figure 2. In the internal air heating only mode, the suction line purge valve 90 can be placed in its first position or in its second position, depending on the magnitude of the movement effect of the suction line. Thermal siphon experienced when crossing the water heat exchanger 60. If the impact of the thermal siphon movement effect is relatively low, the suction line purge valve 90 will be placed in its first position by the system controller as illustrated in Figure 7.

However, if the impact of the thermal siphon movement is moderate to relatively high, the system controller will place the suction line purge valve 90 in its second position as illustrated in Figure 8. When the line bypass valve of suction is in its first position, the system controller will place the bypass flow control valve 92 in its open state. When the suction line bypass valve 90 is in its second position, the system controller will place the bypass flow control valve 92 in its open position, the system controller will place the bypass flow control valve in its position. closed state. Referring now to Figure 7, when in the air-only mode with the suction line bypass valve 90 in its first position, the refrigerant lines 51A and 51B are connected in flow communication by the valve 90 of the suction line bypass and the refrigerant flows in the same route through the various components of the refrigerant circuit as described above with respect to Figure 3. Additionally, lines 93 and 95 are also connected in communication from flow through the suction line bypass valve 90, whereby the refrigerant from the charge tank 70 can enter the refrigerant circuit as long as the solenoid valve 74 in line 73 is opened by the system controller. When the flow to line 95 from line 51A is blocked by regulator valve 94, any refrigerant residing in line 95 on the suction side of regulator valve 94 will be purged back to the compressor through line 73. With reference Now to Figure 8, when in the air-only mode with the suction line bypass valve 90 in its second position, the refrigerant lines 51B and 95 are connected in flow communication by the bypass valve 90 of the suction line and the refrigerant flows to the internal heat exchanger 50 through the refrigerant line 95, instead of through the line 51A, but the refrigerant flows through the various components of the refrigerant circuit in the same sequence as described in the foregoing with respect to Figure 3. The refrigerant lines 93 and 51A are also connected in flow communication by means of the valve 90 d. e suction line bypass. Once the bypass flow control valve 92 on line 51A is closed preventing flow through line 51A, any refrigerant remaining on line 51A on the suction side of valve 92 is vented to the compressor 20 through line 93 to line 73. Additionally, with refrigerant lines 93 and 51A connected in flow communication by valve 90 of Suction line bypass, the refrigerant from the charge tank 74 can enter the refrigerant circuit as long as the solenoid valve 74 in line 73 is opened by the system controller. In the air heating mode with water heating and in the water heating only mode, the suction line bypass valve 90 remains positioned in its second position as illustrated in Figure 8, lines 51B and 95 of The refrigerant is connected in flow communication via the suction line bypass valve 90 and the refrigerant follows to the internal heat exchanger 50 through the refrigerant line 95, instead of through the line 51A, but the refrigerant flows into the refrigerant. through the various components of the refrigerant circuit in the same general sequence as described in the above with respect to Figure 4 and Figure 5, respectively. Once the bypass flow control valve 92 on line 51A is closed preventing flow through line 51A, any refrigerant remaining on line 51A on the suction side of valve 92 is vented to the compressor 20 through line 93 to line 73. Additionally, the refrigerant lines 93 and 51A are connected in flow communication by the suction line bypass valve 92, whereby the refrigerant in the charge tank 70 can get in to the refrigerant circuit whenever the solenoid valve 74 on line 73 is opened by the system controller. In the air heating mode with water heating, the fan 52 of the internal heat exchanger will be operating as illustrated in Figure 4, while in the water heating only mode, the fan 52 of the internal heat exchanger will not be operating as illustrated in Figure 5. As noted above, the heat pump system of the invention must operate effectively in an air-only cooling mode, an air heating and water heating mode, a water-only heating mode, and air, a mode of air heating and water heating, and a water-only heating mode. Both the external heat exchanger 40 and the internal heat exchanger 50 operate as an evaporator, condenser or subcooler, depending on the mode and point of operation, condensation can occur in one or two heat exchangers, and the suction line can be filled with refrigerant in a gaseous state or liquid. As a consequence, the amount of system refrigerant charge required in each mode to ensure operation within an acceptable efficiency coverage will be different for each mode. When water heating is not required, the amount of refrigerant charge required will also be affected by the amount of heat exchange due to the occurrence of the thermal siphon movement in the water-to-water heat exchanger 60. Accordingly, system 100 of the system controller controls the amount of refrigerant flowing through the refrigerant circuit at any time, i.e. the refrigerant charge upon monitoring and adjusting the level of refrigerant in the cargo tank 70 upon opening. and selectively closing the first flow control valve 72 disposed in the refrigerant line 71 and a second flow control valve 74 disposed in the refrigerant line 73. In a more advantageous embodiment, the charging tank 70 is provided with a liquid level meter 80 which generates and transmits a signal indicative of refrigerant level within the charging tank 70 to the controller 100 of the system. The liquid level meter 80 can be configured to transmit a liquid level signal to the system controller 100 continuously, on a periodic basis at specific intervals, or only when required by the controller. Referring now to Figure 10, in operation, when the controller changes from one mode of operation to a new mode of operation, the controller 100 turns on the compressor 20 in the block 101, and then, in the block 102, the controller 100 compare the level of liquid current then in the loading tank 70 with the last liquid level experienced the last time the system was operated in a mode equivalent to the new mode of operation, the last level of liquid experienced when the controller memory was stored. If the current level is the same as the last level experienced for this particular mode of operation, the controller in block 105 activates the discharge temperature control procedure and / or in block 106 the normal load control procedure. However, if the current liquid level is not the same as the last level experienced for this particular mode of operation, the controller 100 will selectively modulate the solenoid valves 72 and 74 to open and close when necessary to adjust the current liquid level. to equal the last level experienced for this particular mode of operation. If the current level is below the last experienced level, in block 103 the controller 100 will close the solenoid valve 74 and modulate the open solenoid valve 72 to drain the refrigerant from the refrigerant circuit to the loading tank 70 until the current reach the last level of experience. Conversely, if the current level is below the last experienced level, the controller 100 in block 104 will close the solenoid valve 72 and modulate the valve 74 open solenoid to drain the refrigerant from the loading tank 70 into the refrigerant circuit until the current liquid level reaches the last level experienced. For example, the controller will open the appropriate valve for a short period of time, for example 2 seconds, close the valve, check the level again and repeat this sequence until the current liquid level is equal to the last level experienced. Once the current level has been matched to the last experienced level, the controller activates the normal load control procedure and / or the discharge temperature control procedure. The system controller 100 may also employ the control procedure discussed herein in embodiments of the heat pump system of the invention that do not include a liquid level sensor in association with the cargo tank 70. However, when the heat pump system changes to a new mode of operation, the system controller 100 first fills the cargo tank with refrigerant in the liquid state or with the refrigerant in the gaseous state depending on the particular mode of operation that is applied. enter If the new mode of operation does not involve water heating, the system controller will proceed according to the procedure illustrated by the flow diagram. block in Figure 11 for filling the coolant tank 70 with liquid coolant. After turning on the compressor 20 in block 201, the system controller in block 202 closes solenoid valve 74 and opens solenoid valve 72 to allow liquid refrigerant to pass from line 71 to charging tank 70. After a programmed time delay in block 203 sufficient to allow the charging tank 70 to be filled with liquid refrigerant, for example, about 3 minutes, the system controller proceeds to adjust the charge of the refrigerant circuit when needed by the discharge temperature control procedure and / or the load control procedure in block 205 when desired. The solenoid valve 72 can be placed either open or closed at this point. However, if the new mode of operation involves water heating, the system controller will proceed according to the procedure illustrated by the block diagram in Figure 12 to fill the refrigerant tank 70 with gaseous refrigerant. After turning on the compressor 20 in block 211, the system controller in block 212 closes solenoid valve 72 and modulates the turning on or off of solenoid valve 74 for a period of time, eg, open for 3 seconds, closed for 17 seconds repeatedly for two minutes to allow the refrigerant in the gaseous state to pass from line 73 to the loading tank 70. After a programmed time delay in block 213 sufficient to allow the charging tank 70 to be filled with gaseous refrigerant, for example, about 3 minutes, the system controller proceeds to adjust the charge of the refrigerant circuit when needed by the discharge temperature control procedure in block 214 and the load control procedure in block 215 when desired. Solenoid valve 74 can be placed either open or closed at this point. In any water heating mode, the controller 100 will turn off the pump 62 when the temperature sensor 89 detects that the water temperature in the water tank 64 has reached a value of the desired limit, for example 60 ° C. According to the discharge temperature limit control procedure, illustrated by the block diagram of Figure 13, with the input of a fixed expansion mode, after turning on the compressor 20 in block 301 and a short delay of time, for example, approximately 30 seconds, the system controller in block 302 compares the current discharge temperature, TDC, that is, the temperature of the refrigerant being discharged from the compressor 20, received from the temperature sensor 85 within a limit of discharge temperature, TDL, preprogrammed in the controller 100. A typical compressor discharge limit may be a desired number of degrees, for example about 7 degrees C, conforming to the manufacturer's application guide specification. A typical compressor discharge temperature limit may be approximately 128 degrees C. If the current discharge temperature, TDC, exceeds the discharge temperature limit, the system controller 100 in block 303 disables the load control procedure if it is currently active, and then in block 304 closes the solenoid valve 72 and modulates the open solenoid valve 74 to drain the refrigerant from the charge tank 70 into the refrigerant circuit through the refrigerant line 73. If the current discharge temperature received from the temperature sensor 85 is equal to or less than the discharge temperature limit, the system controller 100 in block 305 activates the load control procedure if it is not currently active and proceeds to follow the load control procedure to adjust the refrigerant charge in the refrigerant circuit when necessary. In the charge control procedure, illustrated in Figure 14, with the refrigerant charge initially established, after ensuring that the compressor 20 is active in the block 400, the system controller 100 in the block 401 closes both valves 72 and 74 solenoids. After of a brief time delay, for example about one minute, depending on the particular mode of current operation, the system controller in block 403 will compare either or both of the degree of superheat or the degree of subcooling presently present in the system with a margin allowable pre-programmed superheat in controller 100. For example, in air-only cooling and air-cooling modes with water heating, the allowable superheat allowance may be 0.5 to 20 degrees C and the allowable subcooling range may be from 2 to 15 degrees C. In modes of air heating only, air heating with water heating and water heating only, the allowable superheat allowance may be 0.5 to 11 degrees C and the allowable subcooling range may be from 0.5 to 10 degrees C, for example. After determining in block 402 that the system is operating in a fixed expansion mode, the system controller, in block 403, compares the current degree of superheating against the allowable pre-programmed superheat in controller 100. If the Current superheat is below the allowable range, in block 404, the system controller 100 will modulate the open solenoid valve 72 to drain the refrigerant from the refrigerant circuit in the tank 70 load. If the current degree of superheating is above the allowable range, in block 405, the system controller 100 will modulate the open solenoid valve 74 to drain the refrigerant from the charge tank 70 into the refrigerant circuit. If the degree of superheating falls within the allowable superheat range, the system controller proceeds to block 406. If it is operating in a mode without fixed expansion, the system controller, in block 407, compares the current degree of subcooling against a permissible subcooling allowance programmed into the controller. If the current degree of subcooling is above the allowable range, in block 404, the system controller 100 will modulate the open solenoid valve 72 to drain the refrigerant from the refrigerant circuit in the charge tank 70. If the current degree of subcooling is below the allowable range, in block 405, the system controller 100 will modulate the open solenoid valve 74 to drain the refrigerant from the charge tank 70 into the refrigerant circuit. If the degree of subcooling falls within the allowable subcooling range, the system controller proceeds to control the refrigerant charge through the charge control procedure and the discharge temperature limit control as described. The various control parameters presented as examples in the above, such as the discharge temperature limit of the compressor, the various time delays, the superheating margins desired, the desired subcooling margins, are for a typical 5 ton capacity, the split system heat pump system having a water-to-bronze plate water-to-plate refrigerant exchanger 60, a refrigerant tank 70 (charge tank) having a storage capacity of liquid refrigerant of 4 kilograms, a refrigerant charge of the system of 8 kilograms, and lines of general refrigerants of 7 meters. These parameters are presented for purposes of illustration and those skilled in the art will understand that these parameters may vary from the examples presented for different configurations and heat pump capacities. Those of ordinary skill in the art will select precise parameters to be used to implement the invention to better suit the operation of any particular heat pump system. While the present invention has been particularly shown and described with reference to the preferred mode as illustrated in the drawings, it will be understood by someone with experience in the art that several changes in detail can be made therein without departing from the spirit and scope of the invention as defined by the claims.

Claims (18)

1. CLAIMS 1. A refrigerant circuit heat pump system that can operate in at least one air cooling mode and one air heating mode and that has liquid heating capacity characterized in that it comprises: a refrigerant compressor that it has a suction port and a discharge port; a selectively disposable reversing valve having a first port, a second port, a third port and a fourth port, the reversing valve can be placed in a first position to couple the first port and the second port in communication of fluid flow and the third port and the fourth port in fluid flow communication, the reversing valve can be placed in a second position to couple the first port and the third port in fluid flow communication and the second port and the fourth port in fluid flow communication; a refrigerant circuit that provides a closed-loop refrigerant circulation flow path, the refrigerant circuit has a first refrigerant line that establishes a flow path between the compressor discharge port and the first port of the reversing valve , a second line of refrigerant which establishes a flow path between the second port of the reversing valve and the third port of the reversing valve, and a third line of refrigerant that establishes a flow path between the fourth port of the reversing valve and the port of compressor suction; an external heat exchanger operatively associated with the second refrigerant line and adapted to pass the refrigerant passing through the second refrigerant line in heat exchange relationship with the ambient air; an internal heat exchanger operatively associated with the second refrigerant line and adapted to pass the refrigerant passing through the second refrigerant line in heat exchange relation with the air from the comfort zone, the internal heat exchanger disposed downstream of the heat exchanger external with respect to the flow of refrigerant in the air cooling mode and upstream of the external heat exchanger with respect to the flow of refrigerant through the second line of refrigerant in the air heating mode; a liquid-refrigerant heat exchanger operatively associated with the first refrigerant line and adapted to pass the refrigerant passing through the first line of the refrigerant in heat exchange relation with a liquid; and a refrigerant reservoir having an inlet coupled in fluid flow communication to the second refrigerant line at an intermediate location to the external heat exchanger and to the internal heat exchanger and an output coupled in fluid flow communication to the third refrigerant line.
2. 2. The heat pump system according to claim 1, further characterized in that it comprises: a first control valve. flow associated operatively with the coolant reservoir to control the flow of refrigerant from the second refrigerant line to the inlet of the refrigerant reservoir, the first control valve has an open position and a closed position; a second flow control valve operatively associated with the coolant reservoir for controlling the flow of refrigerant between the outlet of the refrigerant reservoir and the third refrigerant line, the second control valve having an open position and a closed position; and a controller operatively associated with the first and second flow control valves, the operating controller for selectively controlling the respective positioning of the first and second flow control valves between their respective open and closed positions to selectively control the refrigerant charge within the refrigerant circuit.
3. The heat pump system according to claim 2, characterized in that the first and second flow control valves comprise valves having at least a partially open position between their respective open and closed positions.; and the controller is further operative to selectively modulate the respective positioning of the first and second flow control valves between their open, at least partially open and closed positions.
4. 4. The heat pump system according to claim 3, characterized in that the first and second flow control valves comprise solenoid valves modulated by pulse amplitude.
5. 5. The heat pump system according to claim 2, further characterized in that it comprises a liquid level sensor operatively associated with the coolant reservoir, the liquid level sensor operative to detect the level of liquid refrigerant in the reservoir of coolant and provides a signal indicative of the level of liquid inside the coolant reservoir to the controller.
6. 6. The heat pump system according to claim 5, characterized in that the controller is operative to selectively control the respective positioning of the first and second flow control valves between their respective open and closed positions to selectively control the refrigerant charge within of the refrigerant circuit in response to the liquid level signal received from the liquid level sensor.
7. The heat pump system according to claim 1, further characterized in that it comprises: a first expansion valve disposed in the second line of intermediate coolant to the external heat exchanger and the location of the coolant reservoir inlet engages in communication of fluid flow with the second refrigerant line; a second expansion valve disposed in the second line of refrigerant intermediate to the internal heat exchanger and the location of the coolant reservoir inlet engages in fluid flow communication with the second line of the refrigerant; the first expansion valve is operatively associated with the internal heat exchanger and the second expansion valve is operatively associated with the external heat exchanger.
8. 8. The heat pump system in accordance with claim 1, further characterized in that it comprises: a first expansion valve branch line operatively associated with the second line of the. coolant to bypass the refrigerant that passes through the second refrigerant line in one direction from the external heat exchanger to the internal heat exchanger around the first expansion valve and through the second expansion valve.
9. The heat pump system according to claim 1, further characterized in that it comprises: a second expansion valve bypass line operatively associated with the second refrigerant line to bypass the refrigerant passing through the second line of coolant in one direction from the internal heat exchanger to the external heat exchanger around the second expansion valve and through the first expansion valve;
10. 10. A refrigerant circuit heat pump system that can operate in at least one air cooling mode and one air heating mode and that has liquid heating capability characterized in that it comprises: a refrigerant compressor having a suction port and a discharge port; a first valve that can be placed selectively having a first port, a second port, a third port and a fourth port, the reversing valve may be placed in a first position for coupling the first port and the second port in fluid flow communication and the third port and the fourth port in fluid flow communication, the reversing valve can be placed in a second position to couple the first port and the third port in fluid flow communication and the second port and the fourth port in fluid flow communication; a refrigerant circuit that provides a closed-loop refrigerant circulation flow path, the refrigerant circuit has a first refrigerant line that establishes a flow path between the compressor discharge port and the first port of the first valve that A second line of refrigerant can be selectively placed which establishes a flow path between the second port of the first valve that can be selectively placed and the third port of the valve that can be selectively placed, and a third line of refrigerant that establishes a flow path between the fourth valve port that can be selectively placed and the suction port of the compressor; an associated external heat exchanger operatively with the second refrigerant line and adapted to pass the refrigerant passing through the second refrigerant line in heat exchange relationship with the ambient air; an internal heat exchanger operatively associated with the second refrigerant line and adapted to pass the refrigerant passing through the second refrigerant line in heat exchange relationship with the air from the comfort zone, the internal heat exchanger disposed downstream of the heat exchanger external with respect to the refrigerant flow in the air cooling mode and upstream of the external heat exchanger with respect to the flow of refrigerant through the second refrigerant line in the air heating mode; a liquid refrigerant heat exchanger operatively associated with the first refrigerant line and adapted to pass the refrigerant passing through the first line of the refrigerant in heat exchange relationship with a liquid; a second valve that can be selectively placed having a first port, a second port, a third port and a fourth port, the second valve that can be selectively placed can be placed in a first position to couple the first port and the second port in fluid flow communication and the third port and the fourth port in fluid flow communication, the second valve that can be selectively placed can be placed in a second position to couple the first port and the third port in fluid flow communication and the second port and the fourth port in fluid flow communication, the second valve that can be selectively placed is disposed in the second line of refrigerant with the first port in flow communication with the internal heat exchanger and the second port in flow communication with the third port of the first valve that can be selectively placed; a refrigerant tank having an inlet coupled by a fourth line of refrigerant in fluid flow communication with the second line of refrigerant in an intermediate location to the external heat exchanger and to the internal heat exchanger and an outlet coupled by a fifth line of refrigerant in communication of fluid flow with the third line of the refrigerant; and a bypass purge flow circuit having a first purge line coupled in flow communication between the fifth line of refrigerant and the third port of the second valve that can be selectively placed and a second purge line coupled in flow communication between the heat exchanger and the fourth port of the second valve that can be selectively placed.
11. 11. The heat pump system according to claim 10, further characterized in that it comprises: a first flow control valve operatively associated with the coolant reservoir to control the flow of refrigerant from the second refrigerant line to the inlet of the refrigerant. refrigerant tank, the first control valve has an open position and a closed position; a second flow control valve operatively associated with the coolant reservoir for controlling the flow of refrigerant between the outlet of the refrigerant reservoir and the third refrigerant line, the second control valve having an open position and a closed position; and a controller operatively associated with the first and second flow control valves, the operating controller for selectively controlling the respective positioning of the first and second flow control valves between their respective open and closed positions to selectively control the load of refrigerant inside the refrigerant circuit.
12. 12. The heat pump system in accordance with claim 11, characterized in that the first and second flow control valves comprise valves having at least a partially open position between their respective open and closed positions; and the controller is further operative to selectively modulate the respective positioning of the first and second flow control valves between their open, at least partially open and closed positions.
13. The heat pump system according to claim 12, characterized in that the first and second flow control valves comprise solenoid valves modulated by pulse amplitude.
14. The heat pump system according to claim 11, further characterized in that it comprises a liquid level sensor operatively associated with the coolant reservoir, the liquid level sensor operative to detect the level of liquid refrigerant in the reservoir of coolant and provides a signal indicative of the level of liquid inside the coolant reservoir to the controller.
15. 15. The heat pump system according to claim 14, characterized in that the controller is operative to selectively control the respective positioning of the first and second flow control valves between their respective open and closed positions for selectively control the refrigerant charge within the refrigerant circuit in response to the liquid level signal received from the liquid level sensor.
16. 16. The heat pump system according to claim 10, further characterized in that it comprises: a first expansion valve disposed in the second line of intermediate coolant to the external heat exchanger and the location of the second coolant reservoir inlet engages in fluid flow communication with the second refrigerant line; a second expansion valve disposed in the second refrigerant line intermediate the internal heat exchanger and the inlet location of the second refrigerant tank is coupled in fluid flow communication with the second refrigerant line; the first expansion valve is operatively associated with the internal heat exchanger and the second expansion valve is operatively associated with the external heat exchanger.
17. 17. The heat pump system according to claim 10, further characterized in that it comprises; a first expansion valve branch line operatively associated with the second refrigerant line to bypass the refrigerant passing through the second refrigerant line in a direction from the external heat exchanger to the internal heat exchanger around the first expansion valve and through the second expansion valve.
18. 18. The heat pump system according to claim 10, further characterized in that it comprises: a second expansion valve bypass line operatively associated with the second refrigerant line to bypass the refrigerant passing through the second line of coolant in one direction from the internal heat exchanger to the external heat exchanger around the second expansion valve and through the first expansion valve.