RU2776886C2 - Steam compression device - Google Patents

Abstract

FIELD: heat engineering.

SUBSTANCE: invention relates to steam compression devices. An intermediate heat accumulator is made with the possibility of charge energy release (i.e., energy return) and/or energy storage and, thereby, regulation of a temperature of a heat source or a temperature of a heat sink in a steam compression cycle. In the steam compression device, the intermediate heat accumulator contains phase transition material (PTM) made with the possibility of charge energy release and/or energy storage and, thereby, regulation of the temperature of the heat source and/or the temperature of the heat sink in the steam compression cycle in different cooling and/or heating systems. The present invention also relates to a method for the selection of phase transition materials (PTM) and/or refrigerants for a steam compression device.

EFFECT: providing the possibility of monitoring the pressure and/or temperature in a heat accumulator, which allows one to effectively manage the entire system.

15 cl, 12 dwg

Description

FIELD OF TECHNOLOGY TO WHICH THE INVENTION RELATES

The present invention relates to a vapor compression device in which the intermediate heat accumulator is configured to release energy (i.e., release energy) of charge and/or store energy and thereby adjust the temperature of the heat source or the temperature of the heat sink in the steam compression cycle.

In particular, the present invention relates to a vapor compression device in which a heat accumulator is located between an evaporator and a condenser, and the vapor compression device comprises a phase change material (PCM) that is capable of releasing energy a (i.e., releasing energy) charge and/or storing energy and thereby adjusting the temperature of the heat source and/or the temperature of the heat sink in the steam compression cycle in various refrigeration and/or heating systems, including: air conditioning for both domestic and industrial needs; transportation of products/materials on vehicles, trains, aircraft, etc. The present invention also relates to a method for selecting phase change materials and/or refrigerants for a vapor compression device.

BACKGROUND OF THE INVENTION

In the prior art, there is a need to provide improved temperature control in a number of systems, including air conditioning, both domestic and industrial; transportation of products/materials on vehicles, trains, aircraft, etc.

The prior art systems suffer from the disadvantages of inadequate and inefficient temperature control and the complexity of the systems, which have proven to be unreliable due to regular breakdowns. In addition, prior art systems having complex structures are very heavy, which adversely affects the transport of the systems and also makes installation difficult.

It is an object of at least one aspect of the present invention to eliminate or at least minimize one or more of the aforementioned problems.

An additional object of at least one aspect of the present invention is to provide an improved vapor compression device.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention, a vapor compression device is provided, comprising:

a pumping unit used to pump the refrigerant;

a condenser capable of condensing the refrigerant;

an evaporator capable of evaporating the refrigerant,

a heat accumulator containing a material with a phase change (MPC);

at least one or a group of temperature and/or pressure sensors capable of monitoring the temperature and/or pressure of the phase change material (PCM) in the thermal storage;

wherein the heat accumulator is operable to be connected to a condenser and/or an evaporator for releasing energy (i.e. energy output) charging and/or storing energy such that the heat accumulator is capable of controlling the temperature of the heat source and/or the temperature of the heat sink in the vapor compression cycle .

Therefore, the present invention relates to a vapor compression device in which an intermediate heat storage device between an evaporator and a condenser is capable of releasing (i.e. delivering energy) charging and/or storing energy and thereby controlling the heat source temperature or heat sink temperature in the vapor compression cycle. . This provides a highly efficient system that is superior to any system known in the art.

The present invention may therefore relate to a temperature and/or pressure controlled vapor compression device.

Any suitable type of refrigerant may be used. The temperature and/or pressure of the refrigerant may also be measured and/or monitored along with the direction of the refrigerant flow.

Therefore, the device according to the present invention can provide a highly efficient method for controlling the flow of refrigerant in the device for maximum efficiency.

The physical state and/or conditions of the heat storage can be closely monitored, for example, through real-time temperature and/or pressure measurements taken on a phase change material (PCM). Alternatively, temperature and/or pressure measurements can be taken continuously and/or continuously, intermittently or intermittently, such as every 30 seconds or every minute. This function can be performed by the regulation control system.

The pumping unit in the preferred embodiments may be any suitable type of compressor. For example, known refrigeration compressors may be used.

Therefore, the vapor compression device has at least one or a group of temperature and/or pressure sensors capable of monitoring and controlling the temperature and/or pressure of the phase change material (PCM) in the thermal storage.

The temperature and/or pressure sensors may be located in any part of or may be an integral part of the heat accumulator, for example, on any surface of the heat accumulator, for example, on the top surface of the accumulator.

At least one or a group of temperature and/or pressure sensors may be immersed in a phase change material (PCM) to provide a range of temperature and/or pressure measurements. Using these measurements, the physical state and/or conditions of the phase change material (PCM) can be monitored and/or adjusted. For example, a series of temperature and/or pressure measurements may be taken to maximize the efficiency of the vapor compression device as a whole.

It has been found that obtaining temperature and/or pressure measurements and determining the temperature and/or pressure provide accurate tracking of the charge energy held by the phase change material (PCM). This allows full adjustment in the device according to the present invention in real time.

The present invention can therefore provide an accurate real-time measurement of the state and physical conditions of a thermal storage device, including charge energy held by the thermal storage device.

The temperature and/or pressure measurement may be carried out using any suitable temperature and pressure measurement devices known in the art. This makes it possible to measure the temperature and/or pressure of the phase change material (PCM) located in the thermal storage in real time. A particular technical advantage of this lies in the possibility of monitoring and/or measuring the pressure and/or temperature in the thermal storage. This allows you to effectively manage the entire system, and the system to be fully manageable.

It is also possible to switch the refrigerant flow and very precisely control it using temperature and/or pressure measurements to provide a highly efficient system.

In a preferred embodiment of the present invention, the evaporator may be positioned vertically below or substantially vertically below the condenser.

The heat accumulator can be located in an intermediate position between the condenser and the evaporator. Therefore, the present invention provides an intermediate step between the heat source and/or heat sink and the temperature controlled environment. Therefore, a thermal storage device containing a phase change material (PCM) can function as an intermediate heat exchanger in the device. Therefore, the heat storage is able to release energy (ie give off energy) charge and/or store energy and thereby regulate the temperature of the heat source or the temperature of the heat sink in the vapor compression device.

Therefore, the device according to the present invention may have an additional functionality, due to which it does not depend on the time between the first stage and the second stage of heat exchange. This independence is achieved through the use of a phase change material (PCM), since energy can be released at any time. The first step may be referred to as pre-cooling or pre-heating, and the second step may be referred to as power-out cooling or power-out heating.

A group and/or network of pipes can be provided connecting various components, e.g. pumping unit (e.g. compressor), condenser, evaporator, heat accumulator, in the device, which are controlled, for example, by valves, such as expansion valves, shut-off valves etc. This is covered in more detail below.

The phase change material (PCM) can function as a heat transfer medium, for example, to a heat exchanger with a refrigerant, i.e. evaporator and/or condenser.

The device may be positioned in a substantially vertical orientation, in which the liquid reservoir may preferably be positioned above the compressor. Typically, the liquid reservoir may be positioned vertically or substantially vertically between the evaporator and the condenser.

The liquid reservoir may be located downstream of the condenser and may be sized to accommodate a supply of liquid refrigerant. Therefore, the liquid reservoir can function as a container serving as a reservoir for some liquid refrigerant.

The compressor may be used to compress and/or pressurize the refrigerant in the system and/or piping of the device.

In a situation where the device is used for pre-cooling in energy recovery or pre-heating, the refrigerant flow moves from top to bottom in a vertically or substantially vertically oriented device. This can be considered as the first cooling/heating step in the present invention.

In a situation where the device is used for pre-cooling or output heating, the refrigerant flow moves from bottom to top in a vertically or substantially vertically oriented device.

The refrigerant flow in the device can be reversed without loss of functionality.

Any suitable type of phase change material (PCM) may be used, including any or combination of the following materials:

paraffinic material such as decane, for example, forming an MFP with a phase transition temperature from about -25°C to about -35°C or about -30°C, if necessary, with additional additives to improve nucleation, crystallization rate and/or cycleability ;

salt-water eutectic, such as sodium chloride and water, for example, forming MFP with a phase transition temperature from about -20°C to about -25°C or about -22°C, if necessary, with additional additives to improve nucleation, speed crystallization and/or cycleability;

salt-water eutectic, such as magnesium sulfate and water, for example, forming MFP with a phase transition temperature from about -10°C to about 0°C or about -5°C, if necessary, with additional additives to improve nucleation, crystallization rate and/or cycleability;

salt-water eutectic, such as sodium sulfate and water, for example, forming MFP with a phase transition temperature from about -5°C to about +5°C or about -1°C, if necessary, with additional additives to improve nucleation, rate crystallization and/or cycleability;

an organic ester, such as methyl laurate, for example, forming an MFP with a phase transition temperature from about 0°C to about 10°C or about 5°C, with optional additives to improve nucleation, crystallization rate and/or cyclability;

a clathrate hydrate such as tetrahydrofuran (THF) and water, for example, forming an MFP with a phase transition temperature from about 0°C to about 10°C or about 5°C, if necessary, with additional additives to improve nucleation, crystallization rate and / or cycling;

an ester, such as dimethyl succinate, for example, forming an MFP with a phase transition temperature from about 15°C to about 25°C or about 18°C, if necessary, with additional additives to improve nucleation, crystallization rate and/or cycleability;

fatty alcohol, such as dodecanol, for example, forming MFP with a phase transition temperature from about 15°C to about 25°C or about 22°C, if necessary, with additional additives to improve nucleation, crystallization rate and/or cycleability;

a salt hydrate, such as sodium sulfate decahydrate, for example, forming an MFP with a phase transition temperature from about 25°C to 35°C or about 32°C, if necessary, with additional additives to improve nucleation, crystallization rate and/or cycleability;

a salt hydrate, such as sodium acetate trihydrate, for example, forming an MFP with a phase transition temperature from about 0°C to about 10°C or about 5°C, if necessary, with additional additives to improve nucleation, crystallization rate and/or cycleability;

a solid-to-solid phase change polyol such as trimethylolethane, for example, forming an MFP with a phase change temperature of about 70° C. to about 95° C. or about 81° C., optionally with additional crystallization rates to improve nucleation and/or cycleability; and

a polyol, such as erythritol, for example, forming an MFP with a phase transition temperature from about 100°C to about 150°C or about 121°C, with optional additives to improve nucleation, crystallization rate and/or cyclability.

A phase change material (PCM) can be selected that has a phase change temperature of about 1°C-20°C, or preferably about 10°C-15°C, above the temperature to which cooling is desired (e.g., the lowest temperature), and/or a phase change temperature that causes the refrigerant to condense at a pressure of 1-10 bar(g) or preferably about 1-5 bar(g) above the desired evaporation pressure. In addition, a phase change material (PCM) may be selected that has a phase change temperature of about 1°C-20°C, or preferably about 10°C-15°C, above the temperature (e.g., minimum temperature) of the ambient conditions, in which the heat pump obtains its heat energy and/or a phase change temperature which causes the refrigerant to evaporate at a pressure of about 1-10 bar(g) or preferably about 1-5 bar(g) above the pressure at which the refrigerant will evaporate, for example, at a given minimum ambient temperature from design conditions.

The refrigerant may be selected from one or more of the following refrigerants: hydrofluorocarbons; and hydrocarbons.

Typical hydrocarbon-based refrigerants include one or more of the following refrigerants: isobutane and propane.

Other suitable refrigerants include carbon dioxide and ammonia.

The following are suitable refrigerants for the present invention, which may be used alone or in any combination:

Refrigerant toxicity: ISO 817 classification A3 B3 High flammability A2 B2 flammable A2L B2L Low flammability A1 B1 Nonflammable Low toxicity High toxicity

Non-flammable refrigerants with low toxicity are preferred

refrigerant GWP* Class P_pair (bar (abs.))
at -20°C P_liquid (bar (abs.))
at 0°C P_kid,
bar (abs.)
at +60°C Areas of use Hydrofluorocarbons R404A 3922 A1 3.00 6.10 28.85 refrigeration of frozen products, process refrigeration R452A 2140 A1 2.62 6.09 28.73 R407F 1824 A1 2.46 6.29 30.35 R449A 1397 A1 2.25 5.72 27.54 R454A 238 A2L 2.17 5.36 25.71 R454C 146 A2L 1.90 4.55 22.24 R134a 1430 A1 1.33 2.93 16.82 supermarket refrigeration systems, process refrigeration, household refrigeration, residential air conditioning systems, mobile air conditioning systems R513A 631 A1 1.42 3.06 16.61 R1234ze 6 A2L 0.97 2.17 12.77 R1234yf four A2L 1.51 3.16 16.42 R410A 2088 A1 3.99 8.01 38.42 medical freezers, LNG liquefaction, residential air conditioning systems R32 675 A2L 4.06 8.13 39.33 R452B 676 A2L 3.09 7.20 34.30 hydrocarbons Isobutane 3 A3 0.72 1.57 8.69 vending machines, transport refrigeration (CO2), industrial refrigeration (ammonia) propane 3 A3 2.45 4.74 21.17 carbon dioxide one A1 19.70 34.85 Supercritical below 31.1°C ammonia 0 B2L 1.90 4.29 26.16

*GWP - Global Warming Potential

The refrigerants listed above can be selected for different temperature ranges.

Groups of pipes can be located in the heat accumulator. The pipes may contain fins, insulation and an outer casing. Any suitable type or orientation of tubes may be used to assist in distributing energy from the phase change material (PCM) or to the phase change material.

On the outside (for example, on the upper surface) of the heat accumulator, if necessary, additional temperature and/or pressure sensors can be located, for example, providing temperature and/or pressure measurements. The temperature and/or pressure sensors may be immersed in a phase change material (PCM) in a heat store.

It should be noted that, in the present invention, it has been found that the pressure of the coolant and/or the temperature of the phase change material (PCM) can indicate the state and physical conditions of the heat storage. The charge energy held by the phase change material (PCM) can also be measured and/or monitored using temperature and/or pressure measurements.

The evaporator may be a fan-cooled coil evaporator. The evaporator may be located below or substantially below the condenser. The evaporator, when it is to be used for cooling, may be used to cool the space intended for cooling. Alternatively, an evaporator may be used to heat from a space that is intended for heating.

Above the evaporator, a condenser may be located, which may be, for example, a fan-cooled coil condenser. The capacitor can be used in environments where heat is dissipated. Alternatively, the condenser may be used to heat the space intended for heating. This ensures the flow of refrigerant in the device from top to bottom. However, the flow direction can be reversed.

Therefore, the function performed by the evaporator and condenser can be reversed and they can replace each other in different cycles.

In addition, the evaporator and condenser can be replaced by other heat exchangers known in the art, such as plate heat exchangers. Therefore, the device according to the present invention is easily adaptable to different situations.

The device may include a reversing valve for reversing the flow of refrigerant. In a particular embodiment, a four-way reversing valve may be used.

A reversing valve and solenoid valves can also be integrated into the device to switch between energy storage and/or energy recovery and hot vapor defrost of heat exchangers.

Switching can be done manually or electronically and depends on the measured temperature and/or pressure and the need for switching. For example, when heating is required, the refrigerant may flow from the heat accumulator, and when cooling is required, the refrigerant may flow into the heat accumulator. Flow switching may be performed as needed to maximize the efficiency of the device.

The device may also include an expansion valve that can be connected to the evaporator when it functions as an active evaporator. The expansion valve may be an electronic or thermostatic valve.

An additional valve can be installed, which can also be used as a shut-off valve. The check valve may be an electronic or manually operated check valve. A shut-off valve can be connected to a reversing valve and a heat accumulator.

An additional valve can be connected to the condenser, which, for example, functions as a non-return valve. A non-return valve can also be connected to the liquid reservoir.

In a preferred embodiment, the liquid reservoir may be located above the compressor and below the condenser.

The device can also contain a desiccant, for example a filter drier, which, if necessary, is additionally located preferably vertically below the liquid reservoir.

The device may also further comprise a viewing window, such as a viewing glass.

The device may also contain expansion devices (eg expansion valves) that can be used for pre-cooling. In case the expansion valve is electronic, no additional solenoids are required.

Typically, the device may also include at least one solenoid valve located between the heat accumulator and the reversing valve. The solenoid valve can be used to turn off the heat accumulator if required.

Solenoid valves can be used and can be replaced by any controllable zone valve.

The device may also contain an accumulator in the suction line, which may be used to expand the refrigerant and ensure that only vapors are returned to the compressor.

The device may also include a crankcase pressure regulator. The crankcase pressure regulator can preferably be operated, for example, at about 2 bar with a refrigerant such as R449A. However, any other suitable type of refrigerant may be used.

An additional solenoid valve can also be installed, connected to the heat accumulator and the liquid reservoir.

Optionally, a solenoid valve can be installed, which can be used for hot vapor defrost.

In alternative embodiments, the implementation of the device may also contain a built-in capillary tube.

In additional embodiments, the implementation of the device may also contain a built-in fluid receiver and a capillary tube.

The device may also contain a built-in microchannel heat exchanger used to condense the refrigerant and store energy in a heat accumulator. Superheated refrigerant vapors can enter the microchannel heat exchanger through the inlet, condense in the channels, and exit as a liquid through the outlet.

A particular aspect and advantage of the present invention is that one device can be used for both heating and cooling with reversible cycles. This means that a device can be provided that can use a single compressor and refrigerant for both energy storage and refrigeration, thus reducing the cost of such systems to the end user.

In the energy recovery cycle, the device needs to transfer thermal energy between an intermediate heat exchanger (i.e. heat storage) and a temperature controlled environment.

The device operates by means of a refrigerant flow driven by a pressure differential across a pumping unit (eg compressor). It is this pressure drop that transports heat in the device. The pressure drop depends on the temperature at which the refrigerant evaporates in the evaporator coil in the evaporator and the temperature at which it condenses in the condenser coil in the condenser.

According to a second aspect of the present invention, a vapor compression device is provided, comprising:

a pumping unit that is used to pump the refrigerant;

a condenser capable of condensing the refrigerant;

an evaporator capable of evaporating the refrigerant,

a heat accumulator containing a material with a phase change (MPC);

wherein the thermal storage is operable to be connected to a condenser and/or an evaporator to release charge energy (i.e., energy output) and/or store energy, such that the thermal storage is capable of controlling the temperature of the heat source and/or the temperature of the heat sink in the vapor compression cycle .

The device according to the second aspect may comprise any of the features defined for the first aspect and any combination thereof.

According to a third aspect of the present invention, there is provided a method for controlling a heat source temperature and/or a heat sink temperature in a vapor compression cycle using an apparatus according to any of the first and second aspects.

The method may include providing:

a pumping unit that is used to pump the refrigerant;

condenser, capable of condensing refrigerant refrigerant;

an evaporator capable of evaporating the refrigerant;

a heat accumulator containing a material with a phase change (MPC);

at least one or a group of temperature and/or pressure sensors capable of monitoring the temperature and/or pressure of the phase change material (PCM) in the thermal storage;

wherein the heat accumulator is configured to be connected to a condenser and/or an evaporator to release an energy charge (i.e. energy output) and/or store energy, wherein the heat accumulator is capable of controlling heat source temperature and/or heat sink temperature in the vapor compression cycle.

According to a fourth aspect of the present invention, there is provided a method for selecting phase change materials (PCMs) and/or refrigerants for a vapor compression device, comprising the steps of:

select legally permitted refrigerants with the lowest global warming potential (GWP) and select a potential refrigerant;

determine the pressure range of the selected potential refrigerant;

determine at what temperatures the potential refrigerant vaporizes and condenses relative to the desired separation temperature (STT) and the minimum ambient temperature (min. TOC);

for each of the list of phase change materials (MPT) with phase transition temperatures (PTT) ranging from 3RT to min. TOC evaluate the pressure of the refrigerant, which occurs at the temperature of the phase change;

editing the list to exclude all potential options that have insufficient pressure drop to allow refrigerant flow between evaporation and condensation in the refrigeration cycle from DFP MFP to minimum TOC and/or to 3TO in the MFP refrigeration cycle;

using tables of saturation of the refrigerant calculate the thermodynamic state of the refrigerant at multiple points (for example, 2-10 or preferably 4 points) of the refrigeration cycle for evaporation and condensation in the refrigeration cycle from DFP MFP to min. TOC and/or to 3RT in the MFP cooling cycle:

- state of the refrigerant at the compressor inlet,

- the state of the refrigerant at the outlet of the compressor,

- state of the refrigerant at the outlet of the condenser,

- state of the refrigerant at the outlet of the evaporator,

calculate the heat load (kW) on the evaporator and/or condenser and the operation (kW) of the compressor for each refrigeration cycle;

using this information, determine the coefficient of performance (EPF) for heating and/or cooling for each pair of refrigerant and MFP;

Using the method described above, any suitable phase change material (PCM) and/or coolant can be used, as discussed above in this application in any of the previous aspects.

In addition, any suitable number of points may be analyzed during the calculation of the thermodynamic state of the refrigerant.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described below, by way of example only, with reference to the drawings, in which:

Fig. 1 is a view of a vapor compression device according to an embodiment of the present invention in the cooling phase of energy recovery.

Fig. 2 is a view of the device shown in FIG. 1 according to an embodiment of the present invention in the pre-cooling phase.

Fig. 3 is a view of the device shown in figures 1 and 2, in accordance with an embodiment of the present invention, in the normal redundancy phase.

Fig. 4 is a view of the device shown in figures 1, 2 and 3 according to an embodiment of the present invention in the hot vapor defrost phase.

Fig. 5 is a view of the device shown in figures 1-4, in accordance with an embodiment of the present invention, in the phase of the refrigeration cycle with the release of energy.

Fig. 6 is an enlarged view of the heat accumulator shown in FIG. 5 in accordance with an embodiment of the present invention.

Fig. 7 is a view of an alternative embodiment in which a heat accumulator with an integrated capillary tube is installed and the device is used as an evaporator in a system with no possibility of reversibility in accordance with an embodiment of the present invention.

Fig. 8 is a view of a further embodiment in which the device shown comprises an integral fluid receiver and capillary tube, the device being used in a reversible system phase in accordance with an embodiment of the present invention.

Fig. 9 is a view of yet another further embodiment in which the device comprises a thermal storage device with a built-in microchannel heat exchanger used to condense refrigerant and store energy in a thermal storage device in accordance with an embodiment of the present invention.

FIG. 10 is a depiction of energy storage in a phase change material (PCM) upon cooling with a phase change temperature of a phase change material (PCM) in accordance with an embodiment of the present invention.

Fig. 11 is an image of the energy output of a thermal storage device using a material with a phase change temperature (PTC) of a material with a phase change (PTC) of about -5°C.

Fig. 12 represents a methodology that allows the selection of a phase change material (PCM) and/or coolant for a particular use, for example, in the device shown in figures 1-9, in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION

The present invention relates to a steam compression device in which the intermediate heat storage is configured to release charge energy (i.e., energy output) and/or store energy and thereby control the heat source temperature or heat sink temperature in the steam compression cycle. At least one or a group of temperature and/or pressure sensors can monitor in real time the temperature and/or pressure of the phase change material (PCM) in the heat store, which allows you to control the heat store and provides a highly efficient system for the vapor compression device.

In the present invention, a phase change material (PCM) is used in the intermediate heat storage, which is located between the condenser and the evaporator. The phase change material (PCM) serves as a heat transfer medium, for example, to a heat exchanger with a refrigerant, i.e. evaporator and/or condenser. Phase change material (PCM) is an alternative heat exchange medium in the form of energy storage. A phase change material (PCM) can be used to form a thermal storage device, as described below.

The purpose of the intermediate heat storage in the device according to the present invention is to provide an intermediate step between the heat source and/or heat sink and the temperature controlled environment. In fact, the device according to the invention has the added functionality of being independent of the time between the first stage and the second heat exchange stage. This independence is achieved through the use of a phase change material (PCM), since energy can be released at any time. The first step may be referred to as pre-cooling or pre-heating, and the second step may be referred to as power-out cooling or power-out heating.

Fig. 1 is a view of a vapor compression device according to the present invention. In FIG. 1, the device is used in the cooling phase of energy recovery, in which the refrigerant can be seen poking from the heat accumulator 4 into the liquid reservoir 13 and down into the evaporator 7.

In FIG. 1, the vapor compression device is shown in a vertical or substantially vertical orientation, in which the liquid reservoir 13 is located preferably above the compressor 1. In addition, the evaporator 7 is located below the condenser 8.

The liquid reservoir 13 is located downstream of the condenser 8 and is sized to accommodate a supply of liquid refrigerant. Therefore, the liquid reservoir 13 functions as a receiver serving as a reservoir for some liquid refrigerant. From the liquid reservoir 13 to the inlet of the expansion valve, a liquid conduit extends which is designed to provide a proper supply of liquid refrigerant and hence contribute to a controlled mass flow of refrigerant.

The device is oriented to best achieve the thermosyphon effect, whereby density differences in the liquid or gaseous refrigerant generally result in the refrigerant gas being more buoyant. This effect is optimized by providing the most efficient vertical or substantially vertical flow path between components and/or flow paths in the components shown in FIG. one.

The discharge pipeline of the compressor rises slightly to the condenser 8 or heat accumulator 4, supplying superheated refrigerant vapor. The liquid conduit then extends downward or substantially downward towards the liquid reservoir 13 to supply the supercooled condensed liquid refrigerant.

The path from the liquid reservoir 13 to the expansion valve 16 or 17 is downward or substantially downward, preferably supplying supercooled condensed liquid refrigerant. The refrigerant experiences a pressure drop as it passes through the expansion valve opening and the common flow path is vertically upward or substantially upward to the outlet of the evaporator 7.

The flow path from the evaporator 7 to the compressor 8 is a design decision for a particular application. Two points need to be considered:

1) The orientation of the flow path is slightly downward to facilitate the return of the circulating compressor oil to the compressor 8, since the refrigerant is less dense to carry oil droplets.

2) Orienting the flow path slightly upwards to take advantage of the refrigerant's natural tendency to rise when it becomes less dense.

Therefore, the device is oriented so as to best facilitate the circulation of compressor oil in the system, see point (1) above. Thus, it has been found that the best orientation of the device shown in FIG. 1 is a vertical or substantially vertical orientation.

The dimensions of the pipelines and the flow path of the device are chosen to facilitate the circulation of compressor oil in the device. The piping diameters are chosen to optimize the refrigerant flow rate and minimize the pressure drop experienced by the refrigerant flow. For example, the refrigerant should flow at a vapor flow rate of about 1-5 m/s, or preferably about 2.5 m/s.

From the liquid reservoir 13 to the inlet of the expansion valve 16, 17 runs a liquid conduit which is designed to provide a proper supply of liquid refrigerant to the inlet and hence promote a controlled refrigerant mass flow.

The vapor compression apparatus will be described in more detail below. It should also be noted that the solid lines between the various components in FIG. 1 show the active flow path. In addition, dotted lines indicate an inactive flow path. The direction of the refrigerant (i.e. energy) flow is shown by arrows.

The vapor compression device comprises a compressor 1. The compressor 1 may be any suitable type of compressor or alternatively any type of pumping unit. However, as noted above, in preferred embodiments, the liquid reservoir 13 is located above the compressor 1. Placing the liquid reservoir 13 above the compressor 1 provides the advantage of a more efficient active flow path.

In the situation where the device is used for power output pre-cooling or pre-heating, the refrigerant flow moves from top to bottom as shown by arrow 2 in the device shown in FIG. 1. This can be considered as the first cooling/heating step in the present invention.

In the situation where the device is used for pre-cooling or output heating, the refrigerant flow moves from bottom to top in the device shown in FIG. 1. This is indicated by arrow 3 in the device.

The flow direction shown by arrows 2, 3 can be reversed without losing the functionality of the device. However, the preferred direction in FIG. 1 is shown by arrows 2, 3.

The heat accumulator 4 is used to accommodate the phase change material 5 (PCF). Any suitable type of phase change material (PCM) 5 may be selected, for example:

paraffinic material such as decane, for example, forming an MFP with a phase transition temperature from about -25°C to about -35°C or about -30°C if necessary, with additional possible additives to improve nucleation, crystallization rate and/or cycleability ;

salt-water eutectic, such as sodium chloride and water, for example, forming MFP with a phase transition temperature from about -20°C to about -25°C or about -22°C, if necessary, with additional additives to improve nucleation, speed crystallization and/or cycleability;

salt-water eutectic, such as magnesium sulfate and water, for example, forming MFP with a phase transition temperature from about -10°C to about 0°C or about -5°C, if necessary, with additional additives to improve nucleation, crystallization rate and/or cycleability;

salt-water eutectic, such as sodium sulfate and water, for example, forming MFP with a phase transition temperature from about -5°C to about +5°C or about -1°C, if necessary, with additional additives to improve nucleation, rate crystallization and/or cycleability;

an organic ester, such as methyl laurate, for example, forming an MFP with a phase transition temperature from about 0°C to about 10°C or about 5°C, if necessary, with additional additives to improve nucleation, crystallization rate and/or cycleability;

a clathrate hydrate such as tetrahydrofuran (THF) and water, for example, forming an MFP with a phase transition temperature from about 0°C to about 10°C or about 5°C, if necessary, with additional additives to improve nucleation, crystallization rate and / or cycling;

an ester, such as dimethyl succinate, for example, forming an MFP with a phase transition temperature from about 15°C to about 25°C or about 18°C, if necessary, with additional additives to improve nucleation, crystallization rate and/or cycleability;

fatty alcohol, such as dodecanol, for example, forming MFP with a phase transition temperature from about 15°C to about 25°C or about 22°C, if necessary, with additional additives to improve nucleation, crystallization rate and/or cycleability;

a salt hydrate, such as sodium sulfate decahydrate, for example, forming an MFP with a phase transition temperature from about 25°C to 35°C or about 32°C, if necessary, with additional additives to improve nucleation, crystallization rate and/or cycleability;

a salt hydrate, such as sodium acetate trihydrate, for example, forming an MFP with a phase transition temperature from about 0°C to about 10°C or about 5°C, if necessary, with additional additives to improve nucleation, crystallization rate and/or cycleability;

a solid phase change polyol, such as trimethylolethane, for example, forming an MFP with a phase transition temperature from about 70°C to about 95°C or about 81°C, if necessary, with additional additives to improve nucleation, crystallization rate and/or cycleability; and

a polyol, such as erythritol, for example, forming an MFP with a phase transition temperature from about 100°C to about 150°C or about 121°C, if necessary, with additional additives to improve nucleation, crystallization rate and/or cyclability.

A phase change material (PCM) is selected that has a phase change temperature of about 1°C-20°C, or preferably about 10°C-15°C, above the temperature to which cooling is desired (e.g., the lowest temperature), and /or a phase change temperature which causes the refrigerant to condense at a pressure of 1-10 bar(g) or preferably about 1-5 bar(g) above the desired evaporation pressure. In addition, a phase change material (PCM) is selected that has a phase change temperature of about 1°C-20°C, or preferably about 10°C-15°C, above the temperature (e.g., minimum temperature) of the ambient conditions in which the heat pump receives its heat energy and/or phase change temperature which causes the refrigerant to evaporate at a pressure of about 1-10 bar(g) or preferably about 1-5 bar(g) above the pressure at which the refrigerant will evaporate at a given minimum ambient temperature from the design conditions.

Therefore, a specific phase change material (PCM) can be selected from a list of known phase change materials (PCMs) for various purposes and applications. Therefore, the system and apparatus of the present invention is easily adaptable to a range of conditions and environments, which are characterized by a wide range of climatic conditions, temperatures and humidity. This provides the advantage that similar devices can be sold worldwide, with only the need to adapt and replace the phase change material (PCM) according to the local environment. Therefore, the apparatus of the present invention provides a commercially viable and highly attractive approach for reducing the manufacturing cost of a vapor compression apparatus.

Inside the heat accumulator 4 is a group of pipes 6. The pipes may contain ribs, insulation and an outer casing (not shown). Pipes 6 of any suitable type and orientation can be used to help distribute the energy of the phase change material (PCM).

As shown in FIG. 1, temperature and/or pressure sensors 23 may additionally be located on the upper surface of the heat storage 4, for example providing temperature measurements T1, T2 and T3 and pressure measurements. Temperature and/or pressure sensors can be immersed in a phase change material (PCM) 5 in a heat accumulator 4.

It should be noted that the present invention has found that the refrigerant pressure and/or the temperature of the phase change material (PCM) can indicate the state and physical conditions of the heat storage 4, including the energy charge held by the phase change material 5 (PCM). For example, the pressure is found to be low in the cold state, for example, for a temperature of -10° C., using the R449A material known in the art, a pressure of 3.6 bar is provided; for a temperature of +60°C using the material R449A, known in the prior art, a pressure of 27.06 bar is provided.

Therefore, the heat storage 4 containing the phase change material (PCM) 5 can function as an intermediate heat exchanger in the device. Therefore, the heat accumulator 4 is configured to release energy charge (ie energy output) and/or store energy and thereby control the temperature of the heat source or the temperature of the heat sink in the vapor compression device. There is no such control device in the prior art.

Fig. 1 also shows an evaporator 7 (for example, a fan coil evaporator). The evaporator 7 is located below the condenser 8. In a situation where the evaporator 7 is used for cooling, it can be used to cool the space intended for cooling. Alternatively, the evaporator 7 can be used for heating from the space intended for heating.

Above the evaporator 7 is a condenser 8 (for example, a coil condenser with fan blowing). Capacitor 8 can be used in environments where heat is removed. Alternatively, the condenser 8 can be used to heat the space to be heated. This allows the refrigerant to flow from top to bottom in the device shown in FIG. 1. However, as discussed below, the flow direction can be reversed.

Therefore, the functions performed by the evaporator 7 and the condenser 8 can be reversed and they can replace each other in different cycles.

In addition, the evaporator 7 and condenser 8 can be replaced by other heat exchangers known in the art, such as plate heat exchangers. Therefore, the device according to the present invention is easily adaptable to different situations.

Valve 9 in the embodiment shown in FIG. 1 is a reversing valve. The reversing valve 9 shown in FIG. 1 is, for example, a four-way reversing valve. The reversing valve 9 is used to reverse the flow when it is necessary to switch between energy recovery and/or hot vapor defrost. Of course, alternatives are contemplated within the scope of the present invention and the device can be reconfigured (ie reconfigured) to provide power storage/power back switching using a reversing valve. The switching may be manual or electronic and may depend on the measured temperature and/or pressure. Therefore, switching of the refrigerant flow can take place on demand and/or on a signal. For example, if heating is required, the refrigerant may flow from the heat accumulator 4, and if cooling is required, the refrigerant flow can be switched to flow into the heat accumulator 4.

The device also includes a shut-off valve 10 which is connected to the condenser 8. The shut-off valve 10 may be an electronic or manually operated shut-off valve.

There is also an additional valve 11 which can be used as a check valve. The check valve 11 may be an electronic or manually operated check valve. Shut-off valve 11 is connected to reversing valve 9 and heat accumulator 4.

Connected to the condenser 8 is an additional valve 12 which, for example, functions as a non-return valve. The check valve 12 is also connected to the liquid reservoir 13.

As shown in FIG. 1, the liquid reservoir 13 is located above the compressor 1 and below the condenser 8. The orientation of the apparatus shown in FIG. 1 is to be considered vertical or substantially vertical.

Fig. 1 also illustrates a drier 14, such as a filter drier, which is preferably located below the liquid reservoir 13.

The device may also optionally comprise a viewing window, such as a viewing glass 15.

The device also contains an expansion device 16 (eg an expansion valve) which can be used for pre-cooling. In case the expansion valve is electronic, the additional solenoid 16A shown in FIG. 1 is not required.

The valve 17 is also an expansion device and is similar to the expansion valve 16. However, the expansion valve 17 is used for power recovery cooling. In case the expansion valve 17 is electronic, the additional solenoid 17A is not required.

In FIG. 1 also shows a solenoid valve 18 located between the heat accumulator 4 and the reversing valve 9. The solenoid valve 18 is used to turn off the heat accumulator 4 when required.

The solenoid valves described above can be used and can be replaced by any controllable zone valve.

There is also a suction accumulator 19 which can be used to expand the refrigerant and ensure that only vapors are returned to the compressor.

There is also a crankcase pressure regulator 20 . The crankcase pressure regulator 20 can preferably be operated, for example, at a pressure of about 2 bar with a refrigerant such as R449A.

There is an additional solenoid valve 21 connected to the heat accumulator 4 and the reservoir 13 for liquid.

Additionally there is a solenoid valve 22 which can be used for hot vapor defrost.

The group of temperature and/or pressure sensors may make temperature and/or pressure measurements at the locations indicated by reference numerals 24 and 25. The temperature and/or pressure measurement may be carried out using any suitable temperature and pressure measuring devices known in the art, for example, temperature and/or pressure sensors. This allows measurement of the temperature and/or pressure of the phase change material (PCM) 5 located in the thermal storage 4. The main technical advantage of this is the ability to track and measure the pressure and/or temperature in the thermal storage 4. This provides feedback to the expansion a valve that regulates the mass flow of the refrigerant, and allows you to effectively control the entire system and fully control the system. Therefore, switching of the refrigerant flow can be carried out at the exact time for maximum energy efficiency.

A particular aspect and advantage of the present invention is that the same device shown in FIG. 1 can be used for both heating and cooling by reversing cycles. This means that a device can be provided that can use a single compressor and refrigerant for both energy storage and refrigeration, thus reducing the cost of such systems to the end user. This also means that the device can be used and made smaller than prior art devices by using a smaller and less powerful compressor. This is due to the fact that part of the work in the device is performed by external power. This is a particular advantage of the present invention.

In the energy recovery cycle, the device needs to transfer thermal energy between the intermediate heat exchanger (ie heat storage 5) and the temperature controlled environment.

The device shown in Fig. 1 works by means of a refrigerant flow driven by a pressure difference across the compressor 1. It is this pressure difference that transports heat in the device. The pressure drop depends on the temperature at which the refrigerant evaporates in the evaporator coil in evaporator 7 and on the temperature at which it condenses in the condenser coil in condenser 8.

An example of the operation of the device shown in Fig. 1 is shown below in Table 1, which shows the operation of the device during the cooling and energy storage phases.

Table 1

Valve actuation
(The top line indicates the components in the diagram) 9 17 16 eleven ten eighteen 21 22 Branch cooling Condensation in 4 (cooling when powering off the MFP) 0 one 0 one 0 0 one 0 Condensing at 8 (regular refrigerator with redundancy) 0 one 0 0 one 0 0 0 Energy storage in a heat accumulator Condensation in 7 (hot vapor defrost) one 0 one one 0 0 0 one Condensation at 8 (MFP pre-cooling) 0 0 one 0 one one 0 0

Table 1 above can be used to set the electrical and/or mechanical control of the refrigerant flow control valves in the present invention, as indicated in the top row. Reference positions in the top line refer to the components shown in figures 1-5. For each component listed on the line, below is a binary indication of which valve position is required for that mode of operation of the system. In this example, "1" means the open position and "0" means the closed position.

Fig. 2 is a view of the device shown in FIG. 1 during the pre-cooling step. Therefore, for the same components, the reference numerals used in FIG. 2 are identical to the reference numerals used in FIG. one.

In FIG. 2, the flow path in the system is adjusted so that the heat storage 4 can be cooled by the evaporation of the refrigerant, and so that the absorbed heat is removed to the ambient air in the condenser 8. This is shown by the active flow path and the corresponding arrows. This mode of operation is called pre-cooling because it cools the phase change material (PCM) to a suitable charge temperature before the system is required to actively cool the temperature controlled compartment.

Fig. 3 represents the device shown in figures 1 and 2, in the mode of operation, which is called the phase of the conventional redundant system. Therefore, for the same components, the reference numerals used in FIG. 3 are the same as the reference numbers used in figures 1 and 2.

In FIG. 3 the flow path in the system is adjusted so that the evaporator 7 can cool the temperature controlled compartment so that the heat absorbed is removed to the ambient air in the condenser 8. This mode of operation is called a normal redundant system because it acts as a fail-safe mode of operation in those cases when the heat accumulator 4 is discharged.

Fig. 4 is a view of the device shown in figures 1-3 in a mode of operation called hot vapor defrost. Therefore, for the same components, the reference numerals used in FIG. 4 are the same as the reference numbers used in figures 1-3.

In FIG. 4, the flow path in the system is adjusted so that the evaporator 7 can be heated by the hot vapor discharged by the compressor 1. This mode of operation is called hot vapor defrost because it is activated to melt the accumulated ice on the outer fins of the evaporator 7 or on the shell.

Fig. 5 is a view of the device shown in figures 1-4 in a refrigeration cycle with energy recovery. Therefore, for the same components, the reference numerals used in FIG. 5 are identical to the reference numerals used in Figures 1-4. In addition, FIG. 5 illustrates that in the heat storage 4 there is a built-in compartment 26 for receiving liquid. The liquid receiving compartment 26 is located at or near the bottom of the heat accumulator 4.

Fig. 5 illustrates the device and components used only as a capacitor in a non-reversible system.

Table 2 below shows the operation of the device shown in FIG. 5, when used only as a capacitor.

table 2

Valve actuation
(The top line indicates the components shown in Fig. 5) 9 17 16 eleven ten eighteen 21 22 Branch cooling Condensation in 4 (cooling when powering off the MFP) 0 one 0 one 0 0 one 0 Condensation in 8 (ambient cooling) 0 one 0 0 one 0 0 0 Energy storage in a heat accumulator Condensation in 7 (hot vapor defrost) one 0 one one 0 0 0 one Condensing at 8 (MFP pre-cooling) 0 0 one 0 one one 0 0

As described above, "1" means the open position and "0" means the closed position when referring to the various components in the system.

Fig. 6 is an enlarged view of the heat storage 4 shown in FIG. 5, when using the device only as a capacitor in a system without the possibility of reversing. The figure shows the material 5 with a phase change (PCF) located in the accumulator, a group of pipes 6 and sensors 23 temperature and/or pressure. The heat accumulator 4 is also in a vertical or substantially vertical position.

Fig. 7 is a representation of an alternative embodiment in which the heat accumulator 4 has an integral capillary tube 27. The apparatus shown in FIG. 7 is only used as an evaporator in a non-reversible system.

Fig. 8 is a view of an embodiment in which the device shown includes an integral fluid receiver 26 and a capillary tube 27. The device and components are shown for a reversible system. Valves 28, 29, 30, 31 are shown which can be used to provide the required refrigerant flow.

Fig. 9 shows a heat accumulator 4 with a built-in microchannel heat exchanger 32 used to condense the refrigerant and store energy in the heat accumulator 4. Superheated refrigerant vapor enters the microchannel heat exchanger through the hole 33, condenses in the channels and exits as a liquid through the hole 34.

The optimization of the device design in accordance with the present invention is to take into account the temperature difference between the required controlled temperature and the selected phase change material (PCM). By choosing a suitable phase change material (PCM), the pressure drop across the compressor will be simultaneously:

1) large enough to facilitate the flow of refrigerant throughout the circuit of the unit. It depends entirely on the pressure drops associated with the lengths, diameters, orientation of the pipelines and the geometry of the inline components.

2) small enough to minimize the work that the compressor needs to do to compress the refrigerant to the required condensing pressure.

As an example to illustrate the present invention, consider two steam compression cycles:

1. Cooling system.

2. Household heat pump.

For the cooling system, the device in accordance with the present invention will use a pre-cooled thermal storage device, which subsequently provides cooling when power is released. Pre-cooling can be achieved, for example, by mechanical or thermoelectric cooling means, natural sources of cold. The cooling effect of energy output can be used to cool departments and industrial processes.

In pre-cooling using a refrigeration cycle, a heat exchanger is immersed in a phase change material (PCM) and acts as an evaporator during the pre-cooling step.

The phase change material (PCM) can be cooled to a dry heat region about 10° C. below the solidification temperature. For example, a phase change material (PCM) that freezes at about -5° C. may be cooled to about -15° C. as a suitable pre-cooling setpoint depending on specific operating conditions.

When the unit is operating in the cooling phase of energy recovery, such as food storage, the refrigerant heat exchanger coil acts as a condenser. As a condenser, the heat exchanger rejects the heat of the refrigerant to the phase change material (PCM).

The capacity of the heat storage according to the present invention depends on the mass of the phase change material (PCM) used, thus the heat sink will continue to absorb heat from the cooling cycle until the temperature of this mass rises.

The heat storage is discharged (depleted) when the phase change material (PCM) melts and its temperature rises to approximately ambient temperature. However, the designer can set up specific cooling controls to limit the pre-cooling and energy recovery cooling temperature limits using standard temperature sensors to start and stop the cooling system.

The limiting factor for refrigeration cycles that use ambient air as a heat sink is that the condensing pressure is climate dependent. If the maximum summer temperatures in tropical climates range from about 30°C to about 40°C, this has a significant impact on the performance of the refrigeration system, as the system needs to compress the refrigerant to a pressure high enough to remove heat at a condensing temperature of approximately 35°C-45 °C.

Tropical environments limit the designer's choice of compressor components because:

1. Compressor discharge temperature becomes dangerous at high temperatures, a typical compressor has a maximum allowable temperature of around 120°C-130°C.

2. Compressor operation is proportional to the pressure difference between its inlet and outlet. The size of the compressor is usually chosen based on its ability to compensate for heat loss in the refrigerated compartment. Therefore, as a minimum requirement, the selected compressor must provide cooling for the range of ambient air conditions in which the system will operate.

Part of the advantage of using a heat store as an intermediate storage as shown in Figures 1-5 in tropical climates is that the heat store can be pre-cooled at night when the ambient temperature is at its lowest. Then during the day, when there is a need for cooling, cooling can be carried out with the return of energy.

This approach to cycling a heat storage day/night is preferred for many applications. For example, in electrically refrigerated food trucks, the pre-cooling cycle may take place at night while the truck is in storage. An external power supply may be used for the pre-cooling cycle, and the vehicle's traction battery may be used for power-out cooling. In this example, the advantage is achieved by reducing the discharge of the vehicle's traction battery and, as a result, providing more power to propel the vehicle.

The choice of phase change material (PCM) is critical to achieving suitable design operating conditions. When choosing a material, the designer must take into account the desired refrigerator compartment temperature, the available choice of phase change materials (PCMs), and relative saturation tables including the pressures required for the refrigerants used.

The closest analogue in the prior art is the replacement of the air heat exchanger with a water tank. In fact, the water reservoir may be pre-cooled and may provide refrigeration when energy is released using a refrigeration cycle.

Fig. 10 represents the energy storage for cooling a phase change material (PCM) with a phase change temperature of the MPC of about -5°C. A phase transition is characterized by a region of latent heat for a material initiated by supercooling of the phase change material (PCT) at a temperature of about 3°C-15°C below or about 5°C below its DFT and culminating in a temperature peak when a temperature rise of about 2°C-6°C or about 3°C-4°C before the material hardens around the temperature sensor.

These temperature phenomena provide a very reliable way to determine the energy storage in a heat store.

In FIG. 10, the start of energy accumulation in the heat accumulator is indicated by the letter A at 0 kJ of stored energy. In fact, by observing the accumulated energy of the total DMF at 5200 kJ, one can determine the subcooling temperature indication in percent for points B-F as follows:

B - Subcooling of the MFP at about 900 kJ, hence the stored energy is about 17.3%.

C - Lower sensor temperature peak at about 2400 kJ, hence the stored energy is about 46%.

D - Temperature peak of the lower sensor at about 3500 kJ, hence the stored energy is about 67%.

E - Temperature peak of the lower sensor at about 4400 kJ, hence the stored energy is about 85%.

F - The set temperature of the MFP, reached with the accumulated energy of about 100%.

Another way to monitor the stored energy in a heat store is to measure the pressure of the refrigerant from the heat store as it evaporates. In FIG. 10, the final pressure reached by the storage of energy in the cell is, for example, about 1.5 barg. This pressure can be measured by installing a pressure transducer at the outlet of the heat accumulator 4. A standard radiometric pressure transducer 0-5 Volts DC, 0-34.5 bar (abs.) can be used.

Fig. 11 illustrates the energy output of a thermal storage device using a material with a phase transition temperature of an MFP material of about -5°C.

It is assumed that the calculated refrigerant condensing pressure is approximately 5 barg for R449a refrigerant, while the corresponding refrigerant condensing temperature is approximately 0°C.

During this test, the T_MFP_cold_cell_top measurement was manually switched to T_MFP_cold_cell_mid at time 2500 seconds.

The bounce indication pressure can be useful in alerting the user to two conditions.

When the heat accumulator operates in the area of latent heat of condensation, for example approx. 5 bar(g)

When the heat accumulator is completely discharged, for example approx. 10 barg.

EXAMPLE 1 Cooling Case : Compartment Cooling

Using the device shown in Fig. 1, a vapor compression cycle has been designed to pre-cool a phase change material (eg, magnesium sulfate) below a phase change temperature of -5°C with a selected pre-cooling end temperature of about -20°C. The system was then reversed to allow the temperature controlled compartment to be cooled down to about -20° C. when power was released. In this study, the heat accumulator was discharged when the condensing temperature reached the ambient temperature.

Usage algorithm choice material With phase transition (MFP ) and/or refrigerant

Referring next to FIG. 12, which presents a method (ie, an algorithm) that allows the selection of a phase change material (PCM) and/or refrigerant for a particular application. The method is divided into two pages of figures: 13/14 and 14/14, and they should be considered together.

Fig. 12 illustrates the selection steps a user must go through to select the best phase change material (PCM) and/or refrigerant for use in the vapor compression device shown in Figures 1-9.

As shown in FIG. 12, the first step is to compile a list of legally permitted refrigerants and prioritize them according to the lowest global warming potential (GWP). Consideration should also be given to the safety aspects of the refrigerant.

The user then lists the evaporating and condensing temperatures for each refrigerant in relation to the separation setpoint (SRT) and the minimum ambient temperature (Min. TOC) using the refrigerant saturation tables.

The user then compiles a list of phase change materials (PCMs) with a phase change temperature (PTT) ranging from the target separation temperature (TST) to the minimum ambient temperature (min. TOC). During this process, the user also ensures that the phase change material (PCM) is suitable for the application with the appropriate phase change temperatures. Security aspects should also be taken into account. For example, the user considers selecting a phase change material (PCM) having a phase change temperature (PTT) that operates at or slightly below the highest possible condensing and evaporating temperatures and melting temperatures. As an example for providing hot water, a phase change material (MPT) which has a phase change temperature (PTT) slightly below 50°C can be selected.

Then, using the device shown in figures 1-9, the user evaluates the pressure of the refrigerant, which occurs in the material with a phase change (PCM), and the corresponding phase change temperature (PCT) in the heat storage 4 for evaporation and/or condensation. This can be done using refrigerant saturation tables. For example, the pressure of a refrigerant in a thermal storage device can be measured using the pressure sensors described above. If necessary, the refrigerant pressure can also be measured in any other part of the vapor compression device.

The next step in the process involves deciding whether the refrigerant has sufficient pressure drop to effect the refrigerant flow between evaporation and/or condensation at the phase change temperature (PTC) of the phase change material (PTC) in the heat store 4 to a minimum ambient temperature (min. TOC) in condenser 8 and/or at set point temperature (ST) of separation (ST) in evaporator 7 to the phase change temperature of the phase change material (PTT) in heat store 4. If the answer is "NO", the refrigerant is removed from the list as an unsuitable choice. In the case of the answer "YES", the process shown in FIG. 12 continues.

The next step in the process involves using refrigerant saturation tables and calculating the thermodynamic state of the refrigerant at points in the refrigeration cycle to evaporate and condense at the phase change temperature (PFT) of the phase change material (PFT) to the minimum ambient temperature (min TOC) during the refrigeration cycle and/ or at a given temperature (STT) of the separation before the cooling cycle of the material with a phase change (MPC):

state of the refrigerant at the compressor inlet,

state of the refrigerant at the outlet of the compressor,

state of the refrigerant at the outlet of the condenser,

condition of the refrigerant entering the evaporator.

For example, the process shown in Fig. 12 includes the selection of a phase change material (PCM) and refrigerant for a heating system in which the heating circuit is to operate at a temperature between X and Y, for example, about 30-60°C, selected based on weather compensation, the choice of a MPC that is in the range of X to Y or below X is carried out using a closed loop process, according to which an initial selection is made for each of the MFP and coolant, and then an iteration step is performed by changing one or the other. A genetic algorithm can also be used.

Therefore, the process shown in Fig. 12 may be used to select a phase change material (PCM) and refrigerant for a refrigeration system that contains a cold-separation refrigeration circuit at temperature X (e.g., about -10°C to about -30°C or about -20° C) and a hot environment into which heat is to be removed, the temperature of which varies from A to B, for example, about 10°C-45°C.

The refrigerant must be an available refrigerant with a supply chain of refrigerant and associated equipment such as compressors, expansion valves, etc.

Refrigerants are also prioritized according to their availability in the future due to legal requirements to reduce the global warming potential (GWP) of refrigerants in the market that are subject to fluorinated gas regulations.

The refrigerant is selected to vaporize during power-out cooling at a temperature of about 2°C to 10°C below, or typically about 5°C below, the set separation temperature (STT) in the evaporator 7 and condense in the heat store 4 at a temperature of 2°C. C-10°C above or typically about 5°C above the phase change temperature (PFT) of the selected phase change material (MPT) solid-to-solid transition is the temperature at which the phase transition to the solid crystalline phase occurs). Evaporation must occur at a pressure of more than 3 bar (abs.) or 1.5 bar (abs.) and less than 10 bar (abs.) or less than 5 bar (abs.), which limits the choice of refrigerant. This choice avoids a shortage of refrigerant in the compressor or liquid refrigerant entering the compressor.

During pre-cooling, the refrigerant typically evaporates in the heat storage 4 at a temperature of about 2°C-10°C below, or typically about 5°C below, the phase change temperature (PTT) of the selected material (MPT) and typically condenses in an ambient heat exchanger (eg fan coil) at a temperature of about 2°C-10°C above or typically about 5°C above the current ambient temperature.

The range is from WTO, which is less than about 2°C-10°C, or typically less than about 5°C, to a temperature of max. TOC is greater than about 2°C-10°C or greater than about 5°C. Everything must be within the allowable range for one refrigerant in the case of one system with compressor, heat accumulator and reversing valve, for example in this case from about -25°C to about +50°C. Feasibility is limited by the maximum working pressure of the system, as well as the choice of heat exchanger, compressor, cost, processability and pressure-related safety. In this regard, the maximum working pressure usually does not exceed about 30 bar (abs.) for a low-cost system and about 200 bar (abs.) for an industrial system. This severely limits the number of refrigerants that can be selected.

An additional factor is that the phase change temperature (PTC) of the phase change material (PTC) is usually selected based on the available phase change materials (PTC), has an acceptably high latent heat, and should be between the 3RT and the min. TOC.

Additional restrictions apply based on the need to ensure a minimum refrigerant flow, this means that there must be a pressure drop, for example, about 2-10 bar or about 5 bar or another value that can be determined by a person skilled in the art.

Referring again to FIG. 12, the next step in the process is to calculate the thermal load (Q) on the evaporator 7 shown in figures 1-5 and/or the condenser in the heat store 4 and the condenser 8 and/or the evaporator 7 and the heat store 4 along with the relative work (W ) compressor for the refrigeration cycle. The following formulas can be used:

Q=mΔh,

W=m∆h.

To illustrate the process of calculating the heat load (Q), refer to the following.

During evaporation and condensation at a relative target temperature (RTT) of separation in the evaporator 7 and a phase transition temperature (PTT) of a phase change material (MPT) in a heat accumulator 4, the load (Q ₇ ) during cooling and/or the load (Q ₄ ) during heating calculated as follows.

First, based on the design conditions specified for the cooling system, the total heat loss in the compartment must be determined. The load (Q ₇ ) during cooling in the evaporator must at least compensate for these heat losses. For example, due to the effectiveness of the insulation of the temperature-controlled compartment, the heat loss can be, for example, about 1 kW. The evaporator cooling load may, for example, be at least about 1 kW. The actual cooling load to be chosen by the designer can be determined by taking into account additional factors, such as the required cooling rate of the compartment, the expected number of door openings during operation.

Then, using the refrigerant saturation tables, the thermodynamic state of the refrigerant at the points of the refrigeration cycle for evaporation and condensation in the refrigeration cycle from the 3RT to the MFP phase transition temperature is calculated.

- Condition of the refrigerant entering the compressor.

- Condition of the refrigerant leaving the compressor.

- Condition of the refrigerant leaving the condenser.

- Condition of the refrigerant leaving the evaporator.

For these states of the refrigerant, the relative enthalpy values are found in the saturation tables for:

- state of the refrigerant at the inlet to the compressor (h ₁ ).

- state of the refrigerant at the outlet of the compressor (h ₂ ),

- the state of the refrigerant at the outlet of the condenser (h ₃ ),

- state of the refrigerant at the outlet of the evaporator (h ₄ ).

Below is the formula for calculating the cooling/heating load on a component:

Q = m*Δh

In this regard, since the cooling load for the evaporator 7 has already been determined, the mass flow of refrigerant through the evaporator 7 can be calculated:

m ₇ \u003d Q ₇ / (h ₄ - h ₁ ).

Knowing the mass flow for the cooling cycle, it is possible to calculate the subsequent load (Q ₄ ) during heating in the heat accumulator 4 and the work (W ₁ ) of the compressor 1.

During evaporation and condensation at a relative temperature of the phase transition of the MFP in a heat accumulator 4 and min. TOC in the condenser 8 cooling load (Q ₄ ) and/or heating load (Q ₈ ) is calculated as follows.

First, the designer selects the cooling load (Q ₈ ) in the thermal storage 4 based on the required cooling rate for the thermal storage.

It then uses the refrigerant saturation tables to calculate the thermodynamic state of the refrigerant at points in the refrigeration cycle for evaporation and condensation in the refrigeration cycle from the MFP's phase change temperature to min. TOC.

Condition of the refrigerant entering the compressor.

Condition of the refrigerant leaving the compressor.

Condition of the refrigerant leaving the condenser.

The state of the refrigerant leaving the evaporator.

For these refrigerant states, finds in saturation tables the relative enthalpy values for:

- state of the refrigerant at the inlet to the compressor (h ₁ ).

- state of the refrigerant at the outlet of the compressor (h ₂ ),

- the state of the refrigerant at the outlet of the condenser (h ₃ ),

- state of the refrigerant at the outlet of the evaporator (h ₄ ).

Below is the formula for calculating the cooling/heating load on a component:

Q = m*Δh.

In this regard, since the cooling load for the heat storage 4 has already been determined, the mass flow of coolant through the heat storage 4 can be calculated:

m ₄ \u003d Q ₄ / (h ₄ -h ₁ ).

Knowing the mass flow for the refrigeration cycle, it is possible to calculate the subsequent load (Q ₈ ) when heated in condenser 8 and the work (W ₁ ) of compressor 1.

Referring again to FIG. 12, the user then calculates an efficiency factor (COP) for heating and/or cooling by dividing the relative heat load of the condenser and/or evaporator by the operation of the compressor.

The refrigerant and phase change material (PCM) data can then be added to the final overview document.

Finally, experiments can be carried out with suitable combinations of refrigerant and phase change material (PCM), prioritized by the lowest global warming potential (GWP) of the refrigerant.

Below is a specific example.

1. Select legally permitted lowest GWP refrigerants and select a potential option.

2. Determine the pressure range of the potential option.

3. Determine the temperatures at which it evaporates and condenses relative to the 3HP and min. TOC.

4. For each of the list of MFPs with phase transition temperatures in the range from ZTO to min. TOC measures the refrigerant pressure that occurs at the phase change temperature.

5. Edit the list to exclude all potential options that have insufficient pressure drop to effect refrigerant flow between evaporation and condensation in the refrigeration cycle from MFP phase transition temperature to minimum TOC and/or to 3RT in the MFP refrigeration cycle.

6. Then, using the refrigerant saturation tables, calculate the thermodynamic state of the refrigerant at the four points in the refrigeration cycle for evaporation and condensation in the refrigeration cycle from the MFP phase change temperature to min. TOC and/or to 3RT in the MFP cooling cycle:

- state of the refrigerant at the compressor inlet,

- the state of the refrigerant at the outlet of the compressor,

- state of the refrigerant at the outlet of the condenser,

- the state of the refrigerant at the outlet of the evaporator.

7. Calculate the heat load (kW) on the evaporator and/or condenser and the work (kW) of the compressor for each refrigeration cycle defined in step 6. Using this information, determine the efficiency factor (COP) for heating and/or cooling for each pair. coolant and MFP.

To select the combination of MFP and refrigerant for a specific heating case, an algorithm can be used, according to which the heating requirement in the condenser is first considered, providing heating of the space and/or hot water and/or heat storage. The heating requirement shall be specified in the system design specifications or at the discretion of the designer. For example, in order to ensure energy storage in a thermal storage device at a rate of, for example, about 2 kW, and in the case of a MFP temperature of, for example, about 58°C, a refrigerant condensing temperature of about 63°C is required. Based on this information, at subsequent stages of the algorithm, the thermodynamic states of the refrigerant in the heating cycle and the mass flow rate of the refrigerant in this cycle can be determined. The choice of MFP for the low temperature thermal storage can then be determined by enumeration of the available materials and refrigerants.

While specific embodiments of the present invention have been described above, it should be understood that deviations from the described embodiments may be within the scope of the present invention. For example, a compressor, condenser, evaporator, and heat storage containing phase change material of any suitable type can be used. In addition, any suitable type of piping network may be used to connect the devices to achieve the objectives of the present invention. In addition, any suitable type of phase change material (PCM) may be used.

Claims (49)

1. A vapor compression device, comprising: a pumping unit used to pump the refrigerant; a condenser capable of condensing the refrigerant; an evaporator capable of evaporating the refrigerant, a heat accumulator containing a material with a phase change (MPC); at least one or a group of temperature and/or pressure sensors capable of monitoring the temperature and/or pressure of a phase change material (PCM) in a thermal storage device; wherein the heat accumulator is configured to be connected to a condenser and/or an evaporator to release charge energy and/or store energy such that the heat accumulator is capable of controlling the heat source temperature and/or heat sink temperature in the vapor compression cycle; wherein there is a group of temperature and/or pressure sensors immersed in the phase change material (PCM) configured to indicate the physical state and physical conditions of the heat accumulator in real time and indicate the need to switch the refrigerant flow. 2. The steam compression device according to claim 1, in which the temperature and/or pressure sensors are configured to continuously and/or continuously or periodically, for example every 30 seconds or every minute, take measurements and provide real-time temperature and/or pressure measurements , which makes it possible to monitor the temperature and pressure of the phase change material (PCM) along with the measurement of the charge energy level in the phase change material (PCM). 3. The vapor compression apparatus according to any one of the preceding claims, wherein the heat accumulator containing a phase change material (PCM) is located in an intermediate position between the condenser and the evaporator, and wherein the heat accumulator provides an intermediate stage between the condenser and the evaporator, which function as heat source and/or heat sink. 4. The vapor compression device according to any one of the preceding claims, wherein the heat accumulator functions as an intermediate heat exchanger. 5. A vapor compression device according to any one of the preceding claims, wherein during the first step the heat store is pre-cooled or pre-heated, and during the second step the heat store outputs energy by cooling or outputs energy by heating. 6. A vapor compression device according to any of the preceding claims, which is in a vertical or substantially vertical orientation, in which the liquid reservoir containing the refrigerant is located above or substantially above the compressor and the liquid reservoir is located vertically or substantially vertically between the evaporator and capacitor. 7. A vapor compression device according to any one of the preceding claims, wherein the pump unit is a compressor that is used to compress and/or pressurize the refrigerant in the piping system of the device. 8. A vapor compression device according to any one of the preceding claims, wherein the phase change material (PCM) used includes any or combination of the following materials: paraffinic material such as decane, for example, forming an MFP with a phase transition temperature from about -25°C to about -35°C or about -30°C, if necessary, with additional additives to improve nucleation, crystallization rate and/or cycleability ; salt-water eutectic, such as sodium chloride and water, for example, forming MFP with a phase transition temperature from about -20°C to about -25°C or about -22°C, if necessary, with additional additives to improve nucleation, speed crystallization and/or cycleability; salt-water eutectic, such as magnesium sulfate and water, for example, forming MFP with a phase transition temperature from about -10°C to about 0°C or about -5°C, if necessary, with additional additives to improve nucleation, crystallization rate and/or cycleability; salt-water eutectic, such as sodium sulfate and water, for example, forming MFP with a phase transition temperature from about -5°C to about +5°C or about -1°C, if necessary, with additional additives to improve nucleation, rate crystallization and/or cycleability; an organic ester, such as methyl laurate, for example, forming an MFP with a phase transition temperature from about 0°C to about 10°C or about 5°C, if necessary, with additional additives to improve nucleation, crystallization rate and/or cycleability; a clathrate hydrate such as tetrahydrofuran (THF) and water, for example, forming an MFP with a phase transition temperature from about 0°C to about 10°C or about 5°C, if necessary, with additional additives to improve nucleation, crystallization rate and / or cycling; an ester, such as dimethyl succinate, for example, forming an MFP with a phase transition temperature from about 15°C to about 25°C or about 18°C, if necessary, with additional additives to improve nucleation, crystallization rate and/or cycleability; fatty alcohol, such as dodecanol, for example, forming MFP with a phase transition temperature from about 15°C to about 25°C or about 22°C, if necessary, with additional additives to improve nucleation, crystallization rate and/or cycleability; a salt hydrate, such as sodium sulfate decahydrate, for example, forming an MFP with a phase transition temperature from about 25°C to 35°C or about 32°C, if necessary, with additional additives to improve nucleation, crystallization rate and/or cycleability; a salt hydrate, such as sodium acetate trihydrate, for example, forming an MFP with a phase transition temperature from about 0°C to about 10°C or about 5°C, if necessary, with additional additives to improve nucleation, crystallization rate and/or cycleability; a solid-to-solid phase change polyol such as trimethylolethane, for example, forming an MFP with a phase change temperature of about 70° C. to about 95° C. or about 81° C., optionally with additional additives to improve nucleation, rate crystallization and/or cycleability; and a polyol, such as erythritol, for example, forming an MFP with a phase transition temperature from about 100°C to about 150°C or about 121°C, with optional additives to improve nucleation, crystallization rate and/or cyclability. 9. A vapor compression apparatus according to any one of the preceding claims, wherein the phase change material (PCM) is selected from a temperature range not as low as the temperature to which the user desires to be cooled, and not as high as the temperature to which the user desires carry out heat dissipation; or wherein a phase change material (PCM) is selected that has a phase change temperature of about 1°C-20°C or about 10°C-15°C above the temperature to which cooling is desired, which is the lowest temperature, and/or a phase change temperature that causes the refrigerant to condense at a pressure of 1-10 bar(g) or preferably about 1-5 bar(g) above the desired evaporation pressure, or where a phase change material (PCM) is selected that has a phase change temperature of about 1°C-20°C or about 10°C-15°C above the temperature which is the minimum ambient temperature in which the heat pump receives its heat energy , and/or a phase change temperature that causes the refrigerant to vaporize at a pressure of about 1-10 bar(g) or about 1-5 bar(g) above the pressure at which the refrigerant will vaporize at a given minimum ambient temperature from design conditions . 10. The vapor compression device according to any one of the preceding claims, in which a group of tubes is located in the heat accumulator and the evaporator is a coil evaporator with fan blowing. 11. A vapor compression device according to any one of the preceding claims, wherein the functions performed by the evaporator and condenser are reversible during different cycles. 12. A vapor compression device according to any one of the preceding claims, comprising a reversing valve for reversing the flow of the refrigerant, if necessary, and switching between charging energy storage and/or energy output, and in which the switching takes place manually or electronically and depends on the measured temperature and/or pressure and the need for switching, and in which, when heating is required, the refrigerant flows from the heat accumulator, and when cooling is required, the refrigerant flows into the heat accumulator, and in which an additional valve is connected to the condenser and liquid reservoir, which functions as a check valve. 13. A vapor compression device according to any one of the preceding claims, also comprising a desiccant such as a filter drier, which is additionally positioned vertically below the liquid reservoir, viewing window, expansion devices such as expansion valves which are used for pre-cooling; at least one solenoid valve located between the heat accumulator and the reversing valve, which is used to turn off the heat accumulator when necessary; and suction accumulator, which is used to direct the flow of refrigerant. 14. A vapor compression device according to any one of the preceding claims, wherein the solenoid valve is connected to a heat accumulator and a liquid reservoir which is used for hot vapor defrosting. 15. A method for controlling a heat source temperature and/or a heat sink temperature in a vapor compression cycle using an apparatus according to any of the first and second aspects, including: a pumping unit used to pump the refrigerant; a condenser capable of condensing the refrigerant; an evaporator capable of evaporating the refrigerant, a heat accumulator containing a material with a phase change (MPC); at least one or a group of temperature and/or pressure sensors capable of monitoring the temperature and/or pressure of the phase change material (PCM) in the heat storage; wherein the heat accumulator is configured to be connected to a condenser and/or an evaporator to release charge energy and/or store energy such that the heat accumulator is capable of controlling heat source temperature and/or heat sink temperature in the vapor compression cycle.

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