WO2001020234A1

WO2001020234A1 - Combination of a refrigerator and a heat pump and a water heater

Info

Publication number: WO2001020234A1
Application number: PCT/US2000/024895
Authority: WO
Inventors: John J. Tomlinson
Original assignee: Ut-Battelle, Llc.
Priority date: 1999-09-15
Filing date: 2000-09-12
Publication date: 2001-03-22
Also published as: AU7478600A

Abstract

A water heating method and apparatus whereby the apparatus has at least one compressor (12), at least one condenser (13), at least one evaporator (11) placed in a refrigeration environment (10), and a refrigerant conduit (15, 16, 17, 18) in fluid communication with each compressor (12), refrigeration condenser (13) and refrigeration evaporator (11). The apparatus is provided with a liquid-cooled condenser (21, 72) comprising a liquid inlet (30) and a liquid outlet (32) and attached to the refrigerant conduit between the compressor (12) and the refrigeration evaporator (11), with a first valve (20) that selectively directs refrigerant into the liquid-cooled condenser (21, 72) and which is located in the refrigerant conduit between the compressor (12) and refrigeration condenser (13) and controlled by a control circuit and with a second evaporator (55), not in the refrigeration environment (10), which receives refrigerant passed through the liquid-cooled condenser (21, 72) and a second expansion device (25).

Description

COMBINATION OF A REFRIGERATOR AND A HEAT PUMP AND A WATER HEATER

STATEMENT OF FEDERALLY SPONSORED RESEARCH

This invention was made with U.S. Government support under Contract No. DE-AC05-96OR22464, awarded by the U.S. Department of Energy to

Lockheed Martin Energy Research Corporation, and the Government has certain rights in this invention.

BACKGROUND OF THE INVENTION

1. Field of the Invention The present invention generally relates to refrigeration systems. More particularly, the present invention relates to a refrigeration system including a heat pump that selectively provides cooling of liquid for refrigeration and heating of water for usage in a water heater.

2. Description of the Related Art A conventional domestic refrigerator (and here the term "refrigerator" is intended to include refrigerators with or without a freezing compartment, as well as freezers of either the upright or chest type) provides cooling to refrigerated environment through the use of a closed vapor compression system. In operation, the refrigerant is compressed and liquefied whereby the refrigerant discharges the heat. The liquid refrigerant is then vaporized such that the refrigerant absorbs the ambient heat and cooling is produced. Ambient air is typically circulated past the cooling refrigerant and heat is removed from the air, and the cooled air is then directed to the refrigerated environment.

There are four basic components to a vapor compression cycle used in a refrigerator. The first component is an evaporator that cools the ambient air that is directed into the refrigerator, thereby cooling its contents. This cooling is provided by a refrigerant working fluid, such as Freon or HFC- 134a, which evaporates as it passes through an evaporator coil. The second component is a compressor connected to the evaporator through a refrigerant tube, and the compressor compresses the refrigerant vapor, thereby raising the pressure and temperature of the refrigerant to cause the refrigerant to liquefy. The liquefied refrigerant then passes to the third basic component, the condenser. The condenser condenses the liquid refrigerant to further release heat therefrom, and the heat released within the condenser requires cooling of the condenser. The fanning of ambient air is most commonly used to cool the condenser of the typical refrigeration system. The use of condenser fan, however, is wasteful of energy and directs hot air into environs surrounding the refrigeration system. This effect is particularly inefficient when the environs surrounding the refrigeration system are desired cooled, such as a living space, and the hot air from the condenser can counteract the effect of other cooling devices such as air conditioners. Moreover, the heat emitted from the condenser is comprised of both the heat absorbed by the evaporator from the refrigerated environment and the heat of compression of the refrigerant provided by the compressor.

The last common component of the vapor compression cycle is an expansion device that partially or fully expands the liquid refrigerant after leaving the condenser and prior to entering the evaporator for absorption of heat. Examples of expansion devices are: short tube orifices, capillary tubes, or thermostatic expansion valves, all of which allow for a pressure differential between the high pressure side of the system caused by the compressor and condenser, and the low pressure side caused in the evaporator.

The common components and their arrangement in a typical refrigerator are shown in the prior art refrigeration system of Figure 1. The air-cooled condenser is shown as 13, the evaporator as 11, the expansion device as 14 and the compressor as 12. As the refrigerator operates, the heat which is rejected at the condenser (C) is the total of the heat removed at the evaporator (E) and the energy provided to the compressor. The condenser heat is denoted as Qc, the heat absorbed at the evaporator is denoted as Qe, and the compressor work denoted as W, the following relation is ascertained:

Qc = Qe + W

The cooling performance of the refrigerator is characterized by a coefficient of performance (COPc) which is defined as:

COPc = Qe/W

Accordingly, the coefficient of performance can be maximized (more cooling for less energy input to the compressor) with high-efficiency compressors, lower refrigerant condensing temperatures, and higher evaporating temperatures. Another common applicant is a hot water heater that accumulates and heats water to provide a store of hot water for usage. Domestic water heaters typically utilize the combustion of gas or the resistance of electrical elements to heat the stored water. The use of electricity to heat the water is inefficient as the energy spent in the elements is far greater than that absorbed by the water held within the heater. One method to electrically heat water more efficiently than by simple resistance requires the use of a vapor compression cycle similar to that described for the refrigeration system. In this system, a heat pump water heater (HPWH) transfers heat to the water with the sum of the energy provided by a compressor and the heat removed from the air surrounding the HPWH by way of an evaporator. Since the HPWH relies on the basic heat pump cycle, the relation described by the first equation above remains. The useful product delivered by the HPWH is condenser heat, Qc, which is used to heat water. The compressor work, W, is what is required to move this heat from the evaporator to the condenser. A heating coefficient of performance, COPh, for this system may be written as:

COPh = Qc/W

The COPh is always higher than the COPc and, in a steady-state process, exceeds COPc by 1, therefore:

COPh = COPc +1

A dedicated HPWH is currently produced by a small number of manufacturers, mostly for commercial water heating requirements. One such device is the OIKOS ENERGY SOURCE BUILDER HPWH manufactured by Crispaire Corporation of Norcross, Georgia. There are several prior art devices that have combined refrigeration units and water heaters. One example described in U.S. Patent No. 4,487,032, issued December 11, 1984 to Speicher for an "Energy Conservation for Household Refrigerators and Water Heaters." Speicher recovers energy from a household refrigerator during a period of refrigerator peak usage (food preparation) and transfers that energy to the household hot water heater in time for a subsequent peak expenditure of hot water (dish-washing). It is also an object of Speicher to greatly reduce or eliminate the cycling of a household hot water heater that was previously necessary to replace heat lost to the ambient through the water tank insulation. Speicher completely replaces the air-cooled condenser of a conventional household refrigerator with a water-cooled condenser. Water passes through the water-cooled condenser, picking up refrigeration heat, and then passes through the oil-cooling loop of the compressor motor, which, according to the prior art, was previously cooled by compressed refrigerant. This twice-heated water is then introduced into the household hot water heater for storage, not through the cold water inlet, but rather through the hot-water outlet.

The refrigerant outlet of the water-cooled condenser is monitored as to temperature. When this temperature rises to a predetermined value, a solenoid valve is opened to admit cold water from a cold water source past a check valve and into the cold end of the water-cooled condenser under the impetus of a pump. Speicher assumes that a refrigerator compressor operates for about 80% of the available time and is capable of making more hot water than can be used in a typical household, and thus yields excess hot water that is stored in an auxiliary water tank or routed to a drain. The Speicher system must either store or dispose of excess hot water because there is no accommodation for heat rejected from the refrigerator to go anywhere but into a cold water source.

Another example of a prior art combined refrigeration and water heating system is U.S. Patent No. 4,507,933, issued April 2, 1985 to Chapa, et al., for a "System Combining Water Heater and Refrigeration Unit." Chapa describes a thermally integrated system combining a refrigeration unit with a water tank that is intended for commercial refrigeration and water heating applications, and the system uses heat produced from a vapor compression cycle for water heating. An external line carries refrigerant between the compressor, an auxiliary pre- condenser contained by a water tank, and main system condensers that are connected in series.

The water tank of Chapa serves as the cooling source for the auxiliary pre- condenser (until the water reaches the temperature of the auxiliary pre-condenser), while storing the heated water produced from auxiliary pre-condenser cooling. An automatic control assembly functions to divide the refrigerant condensation function between the auxiliary and main condensers in response to changing temperatures in the water tank.

Chapa requires a custom water tank to house the auxiliary condenser and its requisite piping. The Chapa system does not serve as a dedicated heat pump water heating system and only recovers heat from the refrigeration cycle. The Chapa system also does not provide space cooling and/or dehumidification.

A further example of a prior art combined refrigeration system and water heater is disclosed in U.S. Patent No. 4,773,231, issued September 27, 1988 to Sulzberger for a "System for Preheating Water Using Thermal Energy from Refrigerant System." Like Chapa, Sulzberger describes a thermally integrated refrigeration/water tank system. Also like Chapa, Sulzberger requires a custom water tank through which refrigerant passes after being compressed, but before the refrigerant reaches the main condenser. Sulzberger is directed primarily at the design of the auxiliary pre-condenser that resides within the water tank.

The Sulzberger system is described as a preheater which uses the thermal energy available in a refrigeration cycle to heat potable water within a double- walled coil (the auxiliary pre-condenser) having an internal vent path within a water filled tank. The system is particularly intended for commercial refrigeration applications. The water tank is designed so that multiple double-walled coils from multiple refrigeration systems may reside in a single tank.

In addition to the need for a specially designed water tank to house the auxiliary condenser, the Sulzberger system does not serve as a dedicated heat pump water heating system, and only recovers heat from the refrigeration cycle. The prior art combined refrigeration systems and water heaters do not adequately address the problems associated with the utilization of excess heat produced from the refrigeration system for heating water. Accordingly, a refrigeration system that can utilize excess heat to efficiently heat water would represent an improvement over the prior art systems. It is to the provision of such a system that the present invention is primarily directed.

SUMMARY OF THE INVENTION

The present invention is a refrigerator heat pump water heater that utilizes excess heat generated by a refrigeration cycle for heating water for a water heater. The present inventive refrigerator heat pump water heater utilizes a heat pump cycle that can efficiently heat water from the accumulated heat in the refrigerant of the refrigeration system. The heat pump cycle has been modified such that when there is need for refrigeration, the heat produced from compression of the refrigerant is selectively captured for water heating by a water-cooled condenser. When refrigeration is not needed by the refrigeration system, the device alternately becomes a dedicated heat pump water heater by transferring ambient heat to the water-cooled condenser. Furthermore, when the present invention operates in a dedicated heat pump water heater mode, the present invention can provide either space cooling or dehumidification.

In its preferred embodiment, the present invention is a refrigerator heat pump water heater for use with a refrigeration system having a refrigerated environment, at least one compressor, at least one condenser, at least one refrigeration evaporator in communication with the refrigerated environment, and a refrigerant conduit in fluid communication with each compressor, condenser and refrigeration evaporator. The refrigerator heat pump water heater includes a liquid-cooled condenser attached to the refrigerant conduit between the compressor and the refrigeration evaporator. The liquid-cooled condenser including a liquid intake line and a liquid outlet line for passage of liquid, preferably being water, in proximity to compressed refrigerant entering the liquid-cooled condenser. The liquid-cooled condenser preferably includes a pump for directing a liquid into the liquid inlet line and out of the liquid outlet line, and thus, through the liquid-cooled condenser.

The refrigerator heat pump water heater further includes a first valve for selectively directing refrigerant into the liquid-cooled condenser, as opposed to the condenser of the refrigeration system, and the first valve is located in the refrigerant conduit between the compressor and refrigeration evaporator. Because of the use of a liquid-cooled condenser, the refrigerator heat pump water heater includes a second evaporator, not in communication with the refrigerated environment, which is located on the refrigeration conduit after the refrigerant has exited the liquid cooled condenser and before the refrigerant enters the compressor. There is also a second evaporator expansion device located in the refrigerant conduit between the second evaporator and the liquid-cooled condenser, and the second evaporator expansion device selectively expands refrigerant entering the second evaporator such that the second evaporator can provide cooling and/or dehumidification to an environment outside of the refrigerated environment.

The refrigerator heat pump water heater further includes a control circuit that controls the activation of at least the first valve to directing refrigerant into the liquid-cooled condenser and thus second evaporator, and thus, not into the condenser and refrigeration evaporator. The control circuit can use several known devices and methods to operate the heat pump cycle and refrigeration cycle, including a timer and sensor feedback control.

The liquid outlet line of the liquid-cooled condenser is connected to a heated water collector that collects the heated water from the liquid-cooled condenser. The heated water collector preferably has a capability to heat water contained within it notwithstanding the provision of heated water from the liquid- cooled condenser.

The refrigerator heat pump water heater can be embodied with the air- cooled condenser of the refrigeration system, the air-cooled portion of an integrated air/water condenser, and the second evaporator can be installed within the refrigerator to enhance the performance of the refrigerator heat pump water heater. One method involves strategically locating the fan in a housing which allows ambient air to first pass the condenser, then the compressor, and finally the second evaporator. In this manner, heat produced at the compressor can be absorbed by the second evaporator. A larger, more efficient compressor could alternatively be used to shorten the refrigerator duty cycle to increase water heating capacity beyond the needs of a typical home.

The present inventive refrigerator heat pump water heater accordingly provides an inventive method of heating water in a refrigeration system. The method for heating water includes the steps of compressing the refrigerant in the compressor, and selectively directing the compressed refrigerant through the liquid-cooled condenser. The water is then heated in the liquid-cooled condenser from proximity to the warm compressed refrigerant, and the water enters the water- cooled condenser through the water inlet line, is heated, and exits the water-cooled condenser through the water outlet line. The refrigerant is then directed from the liquid-cooled condenser to the second evaporator and then expanded in the second evaporator such that the second evaporator is cooled. The method then includes the step of collecting the heated water from the liquid-cooled condenser in the water heater. The present invention offers a commercial advantage in that through use of a second evaporator, the refrigerator heat pump water heater is able to operate as a heat pump water heater, in addition to a refrigeration system. By providing water and air-cooled refrigerant condensers, present invention also accommodates the unusual circumstance when refrigeration, but not hot water production, is necessary. The present invention thus combines two functions, heat pump water heating and heat recovery from refrigeration, which were not previously integrated to produce a efficient thermal exchange system.

The present invention therefore has industrial applicability in that it can be installed in both new and existing refrigeration systems and potential applications include residential and commercial buildings requiring both refrigerators and hot water heaters. Because refrigeration, water heating, and space cooling are all produced by the present invention, the specific design of the refrigerator heat pump water heater component sizing and control algorithm can be altered to meet a variety of needs. Other objects, advantages, and features of the present invention will become apparent upon review of the hereinafter set forth Brief Description of the Drawings, Detailed Description of the Invention, and the Claims. BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a representative diagram of a prior art refrigeration system in a conventional refrigerator.

Figure 2 is a representative diagram of one embodiment of the present inventive refrigeration system in conventional refrigerator having a refrigerated section and a freezer section.

Figure 3a is a representative diagram of the refrigerator heat pump water heater with a first embodiment of an integrated water-cooled condenser.

Figure 3b is a representative diagram of the refrigerator heat pump water heater with a second embodiment of an integrated water-cooled condenser

Figure 4 is a representative diagram of the refrigerator heat pump water heater with a residential hot and cold hot water collector and hot water supply system.

Figure 5 is a schematic representation of a standard refrigerator control circuit modified to control a dual condenser refrigerator heat pump water heater.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings in which like numerals represent like components throughout the several views, Figure 1 illustrates a conventional prior art refrigerator, including a refrigerator body 10, a first evaporator 11, or a refrigeration evaporator for cooling the refrigerated section and/or freezer section, a compressor 12, an ambient air-cooled condenser 13, and an expansion device 14. A refrigerant conduit, represented by refrigeration conduits 15, 16, 17, 18 form a closed loop for containment of the refrigerant. Conduit 15 connects evaporator 11 and compressor 12; conduit 16 connects compressor 12 and condenser 13; conduit 17 connects condenser 13 and expansion device 14; and conduit 18 connects expansion device 14 and evaporator 11. A refrigerant dryer is usually inserted in one of the conduits and solenoid valves are commonly used to control the flow of refrigerant. A first electric fan 50 is commonly used to create a cool air stream around evaporator 11 , and also to defrost evaporator 11 when the refrigeration cycle is off. A second electric fan 51 is commonly used to increase heat transfer for air-cooled condenser 13. A temperature sensing device 9 in can be included in electrical communication with compressor 12 and fans 50 and 51 is capable of relaying an on/off signal when refrigerator cooling is required.

With reference to Figure 2, the present inventive refrigeration heat pump water heater adds several components to the prior art refrigeration system. The refrigerator heat pump water heater includes a liquid-cooled condenser, shown as water-cooled condenser 21, connected at refrigerant conduit 22 between the compressor 12 and a second evaporator 55, connected to each other by refrigerant conduits 23, 26, 27, 29. A first valve 20 is inserted into refrigerant conduit 16 between water-cooled condenser 21 and compressor 12. A second valve 28 is alternately inserted into refrigerant conduit 26 between water-cooler condenser 21 and second evaporator 55. The system alternatively includes a third valve 24 inserted into refrigerant conduit 26 between water-cooled condenser 21 and refrigerant conduit 17. Third valve 24 can prevent backflow of the refrigerant into the water-cooled condenser 21 should a negative suction occur due to the expansion of the warm refrigerant otherwise bypassing the water-cooled condenser.

The second evaporator 55 requires a second expansion device 25 which is between refrigerant conduits 26 and 27, for expanding the refrigerant which has passed through water-cooled condenser 21. Refrigerant conduit 26 is alternately connected into refrigerant conduit 17 between air-cooled condenser 13, and a fourth valve 19 can be provided in refrigerant conduit 26 between refrigerant conduit 17 and expansion valve 25. Refrigerant conduit 29 is connected to second evaporator 55 and refrigeration conduit 15 between compressor 12 and evaporator A third electric fan 52 is alternately included to increase heat transfer from second evaporator 28 or to create a cool air stream from the second evaporator 55 to cool a separate environment from the refrigerated section. By linearly arranging condenser 13, compressor 12, and evaporator 28 a single fan may replace fans 51 and 52. An airflow containment shroud could be beneficially used to increase heat transfer from condenser 13 and compressor 12 to evaporator 28 when relying on a single fan.

Also illustrated in Figure 2 is an inlet water-line 30 interconnecting water- cooled condenser 21 and a cold water supply system. A circulation pump 31 is placed on water inlet line 30 between the cold water supply system and water- cooled condenser 21. An water outlet line 32 interconnecting water-cooled condenser 21 and a hot water supply system is added. A water-valve 33 is alternately placed on water inlet line 30. A water-valve 34 is placed on water outlet line 32. There are a wide variety of specific flow paths and elements that can be alternately used to connect the components of the present invention to a hot and cold water supply system. Further, the components of the refrigerator heat pump water heater can be installed in an existing refrigeration system with solely refrigerant conduit junctures with the existing system.

Figures 3a and 3b illustrate further embodiments of the liquid-cooled condenser of the present invention. Figure 3a illustrates the system with air-cooled condenser 13 and water cooled condenser 21, replaced with integrated condenser 40. Refrigerant conduits 16 and 22 are replaced by a single refrigerant conduit that connects integrated condenser 40 to compressor 12. Refrigerant conduits 17, 23, and 26 are replaced by refrigerant conduit 42, which connects integrated condenser 40 simultaneously to first valve 19 and second valve 28. The third and fourth refrigerant valves, 20 and 24 respectively, are no longer necessary because the refrigerant, by nature, will transfer heat to the coolest portion of the condenser, whether water or ambient-air cooled. Integrated condenser 40 retains the same connections to inlet 30 and outlet 32 water lines. Figure 3b shows a condenser/heat exchanger 41 that substitutes for the usage of two condensers. The condenser portion cooled by fan 51 is in proximity to the heat exchanger for the circulating water from water inlet line 30 to water outlet line 32. However, condensers 40 and 41 require significant modification to the refrigeration system in order to have both refrigeration and heat pump functions. With reference to Figure 4, another embodiment of the refrigerator heat pump water heater 64 is illustrated with a hot water heater 66. The refrigerator heat pump system 64 includes a shroud 68 over the second evaporator 55 and condenser 13 to focus the warm air produced therefrom against the condenser 13 or the water-cooled condenser 72. The refrigerant is directed by valve 70 either into the condenser 13 or water-cooled condenser 72. The water-cooled condenser 72 is connected at water inlet line 30 to a water supply (not shown) and water outlet line 32 to the water heater 66 such that warm water is directed to and accumulated in the water heater 66. The water heater 66 typically includes a self-contained heat source to heat or maintain a hot temperature of the water contained therein. A refrigerant dryer 72 is illustrated as inserted into the system to remove any moisture that enters while charging the system with refrigerant, and the refrigerant dryer 72 is alternately used in all embodiments of the refrigerator heat pump water heater. Figure 5 illustrates a control circuit to control a dual condenser refrigerator heat pump water heater, such as that embodied in Figure 2. Manual switch 63 is in electrical communication with circulation pump 31, water inlet valve 33, and water outlet valve 34. When switch 63 is closed, water continually circulates through water-cooled condenser 21. Temperature sensing device 9 is in electrical communication with relay Kl . Relay Kl is in electrical communication with normally closed valve 19, normally open valve 28, compressor 12, fan 50, and fan 51. When refrigeration is required, temperature sensing device 9 energizes relay Kl. When energized, relay Kl opens valve 19, closes valve 28, and turns on compressor 12, fan 50, and fan 51. When valve 19 is open and valve 28 closed, refrigerant flows to refrigeration evaporator 11 instead of second evaporator 55. Manual switch 62 is in electrical communication with relay K2. Relay K2 is in electrical communication with normally open valve 20, normally closed valve 24, compressor 12, and fan 51. If switch 62 is in the first position, relay K_2 is not energized and valve 20 is open, while valve 24 is closed. The illustrated circuit can accordingly operate like a conventional refrigerator. If switch 62 is in the second position, relay K2 is always energized. Energizing K2 results in valve 20 closing, valve 24 opening, compressor 12 activating, and fan 51 activating.

The refrigerator heat pump water heater further operates as a dedicated heat pump water heater, with temperature sensing device 9 activating the system to control if heat is drawn from refrigeration evaporator 11 or second evaporator 55. When in the third position, manual switch 62 is in electrical communication with temperature sensing device 35. Temperature sensing device 35, placed on inlet water line 30, is also in electrical communication with relay K2. When temperature sensing device 35 is below a set temperature (preferably 130° F) relay K2 is energized, resulting in the same operation as when manual switch 62 is in the second position. When temperature sensing device 35 is above the set temperature, the device opens thereby creating the same operational state as when manual switch 62 is in the first position (open).

In summary, manual switch 62 controls whether heat is rejected from condenser 13 cooled or water-cooled condenser 21. When in the first position, only condenser 13 operates, and when in the second position, only water-cooled condenser 21 operates. When in the third position, temperature sensing device 35 selects which condenser operates.

As in Figure 2 and Figure 5, temperature sensing device 9, through relay Kl, selects whether heat is removed from refrigeration evaporator 11 or second evaporator 55 of an integrated condenser refrigerator heat pump water heater. The manner of operation is not selected by the refrigerant valves 20 and 24 depicted in Figure 2, but by the determination as to whether circulation pump 31 provides water of a lower temperature than the ambient air surrounding integrated condenser 40. Control circuitry similar to that depicted in Figure 5 could be adapted to switch fan 51 on, thereby lowering the temperature of ambient air surrounding integrated condenser 40, when the inlet water supply exceeds 120° F.

In operation, as shown in Figure 2, heat is selectively transferred from within refrigerator body 10 to the cold water supply system through a refrigerant that absorbs heat from within the refrigerator body at the refrigeration evaporator 11, passes through refrigerant conduit 15, is compressed by compressor 12, passes through refrigerant conduits 16 and 22, and passes through water-cooled condenser 21. Within water-cooled condenser 21 refrigerant heat is transferred to cold water introduced from cold water inlet 30 by valve 33 and circulation pump 31. The refrigerant then passes through refrigerant conduit 23, valve 24, refrigeration conduit 17 and valve 19 to reach first expansion device 14. Upon expansion, the refrigerant returns to evaporator 11 to take on heat, by way of refrigeration conduit 18. Refrigerant valves 20 and 28 remain closed.

Heat is selectively transferred from ambient air to the cold water supply system through the refrigerant absorbing the heat of compression in compressor 12 and then being condensed in water-cooled condenser 21 to cool the refrigerant. Water is circulated into the water-cooled condenser 21 though the water inlet line 30 and the heat emitted from the cooling refrigerant is transferred to the water. The heated water is then sent from the water-cooled condenser typically to a water heater, such as water heater 66 in Figure 4.

The second evaporator 55 has several possible utilitarian uses. The second evaporator 55 can be used to provide refrigeration to another environment, with fan 52 directing an airstream across the evaporator. The second evaporator 55 can also be used as a dehumidifier as the cooling of the second evaporator 55 causes condensation on the evaporator and thus, dehumidification of ambient air.

The present inventive refrigerator heat pump water heater accordingly provides an inventive method of heating water in a refrigeration system, as particularly illustrated in Fig. 2. The method for heating water includes the steps of compressing the refrigerant in the compressor 12, and selectively directing the compressed refrigerant through the water-cooled condenser 21. The water is then heated in the water-cooled condenser 21 from proximity to the warm compressed refrigerant, and the water enters the water-cooled condenser through the water inlet line 30, is heated, and exits the water-cooled condenser 21 through the water outlet line 32. The refrigerant is then directed from the liquid-cooled condenser 21 to the second evaporator 55 and then expanded in the second evaporator 55 by second evaporator expansion device 25 such that the second evaporator 55 absorbs heat. The method then includes the step of collecting the heated water from the liquid- cooled condenser 21 in the water heater 66 (Figure 3).

The direction of the refrigerant in preferably accomplished through at least the use of the first valve 20. The control circuit of Fig. 5 alternately controls the execution of the steps by the refrigerator heat pump water heater by actuating the valves of the system. And the ultimate usage of the heat absorbed by the second evaporator 55 can constitute a further step in the inventive method, either air conditioning or dehumidification. While there has been shown the preferred and alternate embodiments of the present invention, it is to be understood that certain changes can be made in the forms and the arrangement of the components and in the steps of the inventive method without departing from the spirit and scope of the invention as set forth in the Claims appended herewith. In addition, all elements recited in means-plus- function language are intended to include any structure, material, or act for performing the recited function in combination with the other claimed elements as would be known to one of skill in the art.

Claims

What is claimed is:

1. In a refrigeration system having a refrigerated environment, at least one compressor, at least one condenser, and at least one refrigeration evaporator in communication with the refrigerated environment, the system further having a refrigerant conduit in fluid communication with each compressor, condenser and refrigeration evaporator, the improvement comprising: a liquid-cooled condenser attached to the refrigerant conduit between the compressor and the refrigeration evaporator, said liquid-cooled condenser including a liquid inlet line and a liquid outlet line for passage of liquid in proximity to refrigerant entering said liquid-cooled condenser from the compressor, said liquid-cooled condenser including a pump for directing a liquid into said liquid inlet line and out of said liquid outlet line; a first valve for selectively directing refrigerant into said liquid-cooled condenser, said first valve located in said refrigerant conduit between the compressor and refrigeration evaporator; a second evaporator not in communication with the refrigerated environment, said second evaporator located on said refrigeration conduit between said liquid cooled condenser and the compressor, said second evaporator receiving refrigerant passed through said liquid-cooled condenser; a second evaporator expansion device located in the refrigerant conduit between said second evaporator and said liquid-cooled condenser, said second evaporator expansion device selectively expanding refrigerant entering said second evaporator; and control means for controlling the activation of the first valve and directing refrigerant into said liquid-cooled condenser.

2. The improved refrigeration system of claim 1, further including a second valve for selectively directing the refrigerant into said second evaporator, said second valve located between said liquid-cooled condenser and said second evaporator expansion device, and said control means controls the activation of said second valve to selectively direct refrigerant into said second evaporator.

3. The improved refrigeration system of claim 1, wherein the control means is an electrical circuit.

4. The improved refrigeration system of claim 2, further comprising a third valve in the refrigerant conduit between the liquid-cooled condenser and the second evaporator, wherein said third valve prevents backflow of refrigerant into said liquid-cooled condenser.

5. The improved refrigeration system of claim 1, wherein said liquid outlet line of said liquid-cooled condenser is connected to a liquid receptacle for receiving warmed liquid from the liquid-cooled condenser.

6. A refrigerator heat pump water heater for use with a refrigeration system having a refrigerated environment, at least one compressor, at least one condenser, and at least one refrigeration evaporator in communication with the refrigerated environment, the system further having a refrigerant conduit in fluid communication with each compressor, condenser and refrigeration evaporator, said refrigerator heat pump water heater comprising: a liquid-cooled condenser attached to the refrigerant conduit between the compressor and the refrigeration evaporator, said liquid-cooled condenser including a liquid intake line and a liquid outlet line for passage of liquid in proximity to refrigerant entering said liquid-cooled condenser from the compressor, said liquid-cooled condenser including a pump for directing a liquid into said liquid inlet line and out of said liquid outlet line; a first valve for selectively directing refrigerant into said liquid-cooled condenser, said first valve located in said refrigerant conduit between the compressor and refrigeration evaporator; a second evaporator not in communication with the refrigerated environment, said second evaporator located on said refrigeration conduit between said liquid cooled condenser and the compressor, said second evaporator receiving refrigerant passed through said liquid-cooled condenser; a second evaporator expansion device located in the refrigerant conduit between said second evaporator and said liquid-cooled condenser, said second evaporator expansion device selectively expanding refrigerant entering said second evaporator; a control circuit for controlling the activation of the first valve and directing refrigerant into said liquid-cooled condenser; and a heated water collector for collecting water that has been heated in said liquid-cooled condenser, said heated water collector connect to said liquid outlet line of said liquid-cooled condenser.

7. The refrigerator heat pump water heater of claim 6, further including a second valve for selectively directing the refrigerant into said second evaporator, said second valve located between said liquid-cooled condenser and said second evaporator expansion device, and said control circuit controls the activation of said second valve to selectively direct refrigerant into said second evaporator.

8. The refrigerator heat pump water heater of claim 7, wherein said first valve and said second valve are solenoid valves.

9. The refrigerator heat pump water heater of claim 6, further comprising a third valve in the refrigerant conduit between the liquid-cooled condenser and the second evaporator, wherein said third valve prevents backflow of refrigerant into said liquid-cooled condenser.

10. The refrigerator heat pump water heater of claim 6, wherein said liquid outlet line of said liquid-cooled condenser is connected to a liquid receptacle for receiving warmed liquid from the liquid-cooled condenser.

11. A method of heating water in a refrigeration system having a refrigerated environment, at least one compressor, at least one condenser, at least one water-cooled condenser, at least one refrigeration evaporator in connection to the refrigerated environment, a second evaporator not connected to the refrigerated environment, and a refrigerant conduit in fluid communication with each compressor, condenser, water-cooled condenser, refrigeration evaporator, and second evaporator, and the water-cooled condenser having a water inlet line and a water outlet line, the water outlet line connected to a water heater, the method comprising the steps of: compressing the refrigerant in the compressor; selectively directing the compressed refrigerant through the water-cooled condenser; heating the water in the water-cooled condenser, the water entering the water-cooled condenser through the water inlet line, being heated, and the heated water exiting the water-cooled condenser through the water outlet line; directing the refrigerant from the water-cooled condenser to the second evaporator; expanding the refrigerant in the second evaporator; and collecting the heated water in the water heater.

12. The method of claim 11, wherein the step of directing the compressed refrigerant through the water-cooled condenser is directing the compressed refrigerant with a solenoid valve in the refrigerant conduit between the compressor and water-cooled condenser.

13. The method of claim 12, further including the step of selectively activating the directing of the compressed refrigerant through the water-cooled condenser to thereby control the collection of heated water in the water heater with a control circuit controlling the solenoid valve.

14. The method of claim 11, wherein the water-cooled condenser includes a pump and the steps of water entering the water-cooled condenser through the water inlet line, exiting the water-cooled condenser through the water outlet line, and collecting the water in the water heater are accomplished by the pump pumping the water through the water-cooled condenser.

15. The method of claim 14, wherein the water-cooled condenser further includes a first valve on the water inlet line and a second valve on the water outlet line, and the method further includes the steps of selectively activating the intake of water with the first valve and selectively collecting water in the water heater with activation of the second valve.

16. The method of claim 11, further including the step of selectively dehumidifying an environment through placing the second evaporator in the environment and expanding the refrigerant in the second evaporator.