Increasing the power output of thermodynamic machines

Abstract

The present invention relates to an apparatus comprising a first thermodynamic machine of the vapor compression type through which a refrigerant circulates and a second thermodynamic machine through which a heat-carrying fluid circulates. The first machine includes a compressor (5), a condenser (2), an expansion valve (6), and an evaporator (7), which together with the refrigerant determine the nominal thermal output of the first machine. The second machine includes a fluid circulator (1) configured to flow a heat-carrying fluid through the second machine so that the heat-carrying fluid is in thermal contact with the refrigerant. The fluid circulator (1) is designed so that the maximum flow rate of the heat-carrying fluid is greater than 120% of the nominal flow rate. The first machine includes a first piping having a first cross-sectional expansion (3) between the compressor (5) and the condenser (2) and a second cross-sectional expansion (4) between the condenser (2) and the expansion valve (6).

Description

[Technical Field]

[0001] The present invention is in the field of thermodynamic machines, and more particularly relates to increasing the heating or cooling power of machines of the vapor compression type. [Background technology]

[0002] Vapor compression thermodynamic machines are known from the prior art that can be used as heat pumps (i.e., the utility is on the heat sink side) to heat by removing heat from a cold source and transferring it to a heat sink, and vapor compression thermodynamic machines that can be used as coolers (i.e., the utility is on the source side) to remove heat from a cold source and transfer it to a heat sink.

[0003] Vapor compression thermodynamic machines typically consist of a compressor, condenser, expansion valve, and evaporator connected in series in a closed fluid circuit containing a refrigerant, or "primary fluid." Such machines exchange heat with a secondary refrigerant circuit (a cold source) or a heat-carrying circuit (a heat sink) via heat exchangers (evaporator and condenser), respectively. The secondary refrigerant or heat-carrying fluid, also referred to as the "secondary fluid," can be in either a gaseous state (such as air) or a liquid state (such as water), depending on the application.

[0004] In either case, heat transfer, whether by heat rejected to a heat sink or absorbed from a cold source, occurs outside the thermodynamic machine by a fluid flow, which is a secondary fluid transported in a fluid circuit by a fluid circulator carrying the secondary fluid, and which is in thermal contact with one of the heat exchangers of the machine.

[0005] If the secondary fluid is in liquid phase, the fluid circulator is typically a pump, and if the fluid is in gas phase, the fluid circulator is typically a fan.

[0006] The machine's components, namely the compressor, condenser, expansion valve, and evaporator, together with the refrigerant used, determine the useful power or nominal heat output of the thermodynamic machine. This nominal heat output is the amount of heat, expressed in kilowatts (kW) per unit time, transferred to the secondary fluid under test conditions according to the appropriate standards and standard practices (nominal operating phase). In particular, the EN 14511-2 standard specifies test conditions for determining the characteristics and performance of air conditioners, liquid refrigeration packages, and heat pumps with electrically operated compressors for heating and cooling. The nominal heat output is generally part of the technical specifications provided by the thermodynamic machine manufacturer.

[0007] The circulator must ensure a nominal flow rate, which, as is known, is derived from the nominal heat output of the thermodynamic machine and a predetermined change (i.e., difference) in the temperature or enthalpy of the secondary fluid at the inlet and outlet of the exchanger. More specifically, the nominal flow rate of the secondary fluid is equal to the nominal heat output, multiplied by the predetermined change in enthalpy. The temperature or enthalpy change is predetermined in the sense that it is determined by an appropriate standard or standard practice. In particular, for heat pumps (HPs) that use water as the secondary fluid, the EN 14511-2 standard specifies the change in water temperature between the inlet and outlet of the exchanger for various types of HPs. That is, the change in water temperature is set to 5°C for low-temperature HPs, 8°C for medium-temperature HPs, and 10°C for high-temperature HPs. The change in enthalpy is equal to the product of the specific heat of water (cp=4.18 kJ / kg·K) multiplied by the change in temperature. From this, the above-mentioned predetermined change in enthalpy imposed by the standard can be derived. In the case of a low-temperature HP, this change in temperature of 5°C corresponds to a change in enthalpy of 5 x 4.18 = 20.9 kJ / kg. The nominal flow rate is equal to the nominal power output (under the nominal test conditions specified in the standard) divided by this enthalpy difference: nominal flow rate = nominal power output / 20.9. The nominal flow rate generally forms part of the technical specifications reported by the manufacturer of the thermodynamic machine.

[0008] The fluid circulator is designed to provide such a nominal secondary fluid flow rate depending on the pressure drop characteristics of the secondary circuit. Typically, the fluid circulator selected will operate within a particular flow rate range and will be able to provide a maximum flow rate greater than the selected nominal flow rate. In practice, however, this maximum flow rate will not exceed 120% of the nominal flow rate.

[0009] Therefore, in the prior art: - the flow rate of the liquid secondary fluid is ensured by a pump designed for a nominal flow rate corresponding to the nominal thermal power of the machine at the temperature (or enthalpy) difference set at the inlet and outlet of the exchanger by standards or standard practice; The flow rate of the gaseous secondary fluid is ensured by a fan or fan system designed for a nominal flow rate corresponding to the nominal thermal power of the machine at the temperature (or enthalpy) difference set at the inlet and outlet of the exchanger according to standards or standard practice, i.e. the fluid circulator is designed for the nominal thermal power of the thermodynamic machine.

[0010] In conventional systems, increasing the flow rate of the secondary fluid in contact with the exchangers of a thermodynamic machine results in, at best, a constant output and, at worst, a waste of power. That is, oversizing the pump in the circuit of a liquid secondary fluid (e.g., water) of a thermodynamic machine or oversizing the fan in the circuit of a gaseous secondary fluid (e.g., air) of a thermodynamic machine does nothing to improve the energy efficiency or the heat output achieved by the thermodynamic machine. Moreover, such oversizing of fluid circulators has been carefully avoided in the prior art because it represents added cost, increased space requirements, and excess consumption.

[0011] In some unconventional vapor compression thermodynamic machines of the prior art, piping expansions, i.e., "piping internal cross-sectional expansions" or "cross-sectional expansions," are provided in the fluid circuit containing the primary refrigerant to improve the thermal efficiency of the vapor compression machine. Examples of such expansions are described, for example, in patent document EP 3071901 B1. These expansions typically include an inlet space of increasing cross-section and an outlet space of decreasing cross-section for piping with a given internal cross-sectional area upstream and downstream of the expansion.

[0012] These extensions are typically extensions of the machine's fluid circuit, with at least one tube fluidly connecting an inlet volume to an outlet volume. An extension containing multiple tubes forms a piping division (and refrigerant flow division) between the inlet and outlet volumes of the fluid circuit, typically referred to as a branch section, where the piping divides into parallel sub-tubes. This type of extension is typically referred to as a "branched extension." Unlike a multi-tube heat exchanger, a branched extension does not include a secondary fluid circuit.

[0013] The expansions are usually installed in the gaseous or liquid medium of the so-called high-pressure part of the thermodynamic machine, i.e., between the compressor and the condenser (gaseous expansions) or between the condenser and the expansion valve (liquid expansions).These expansions are installed in such vapor compression thermodynamic machines to increase the power output and the coefficient of performance (COP) of the machine. Summary of the Invention [Problem to be solved by the invention]

[0014] There is a constant desire to improve thermodynamic machines in terms of energy efficiency and heat output. [Means for solving the problem]

[0015] In this context, the invention relates to an apparatus comprising a first thermodynamic machine of the vapor compression type through which a refrigerant circulates and a second thermodynamic machine through which a heat-carrying fluid circulates, the first machine comprising a compressor, a condenser, an expansion valve and an evaporator which together with the refrigerant determine the nominal heat output of the first machine, the second machine comprising a fluid circulator arranged to make the heat-carrying fluid flow through the second machine in thermal contact with the refrigerant, the nominal heat output exchanged by the second machine being determined by the product of a nominal flow rate multiplied by a predetermined change in enthalpy of the heat-carrying fluid, the fluid circulator being arranged so that the maximum flow rate of the heat-carrying fluid is greater than 120% of the nominal flow rate, the first machine having an internal cross section in the width direction. the first piping having a first cross-sectional expansion between the compressor and the expansion valve and extending lengthwise through the condenser, the first piping having a first cross-sectional expansion between the compressor and the condenser, the first piping having a second cross-sectional expansion between the condenser and the expansion valve, the first cross-sectional expansion including a first inlet space of increasing cross-section, a first outlet space of decreasing cross-section, and a first tube fluidly connecting the first inlet space to the first outlet space, and the second cross-sectional expansion including a second inlet space of increasing cross-section, a second outlet space of decreasing cross-section, and at least one second tube fluidly connecting the second inlet space to the second outlet space.

[0016] "Vapor compression thermodynamic machine" means a system that operates using a refrigerant, and exchanges energy between two thermodynamic machines through a circulating heat-carrying fluid as the refrigerant undergoes cyclical changes (compression → condensation → expansion → evaporation).

[0017] "Thermodynamic machine in which a heat-carrying fluid circulates" means a fluid circuit in which a heat-carrying fluid is circulated to transport heat entering from the condenser of a vapor compression type thermodynamic machine or heat to be transferred to the evaporator of a vapor compression type thermodynamic machine.

[0018] Within the scope of the present invention, the term "heat-carrying fluid" or "secondary fluid" refers to any fluid capable of transporting heat within the thermodynamic machine in which the heat-carrying fluid circulates, i.e., these terms encompass both heat-carrying fluids and refrigerant fluids.

[0019] Finally, the term "fluidly connected" as applied to two elements should be understood to mean that "fluid can be transported" between the two elements without loss of fluid in transport or shunting of fluid between the two elements, i.e., fluid contact is established between the two elements.

[0020] Furthermore, since the fluid circulator is configured so that the maximum flow rate of the heat carrier fluid exceeds (i.e., is equal to or greater than) 120% of the nominal flow rate, i.e., the maximum flow rate is equal to or greater than 1.2 times the nominal flow rate, it can be said to be "excessive" compared to a fluid circulator configured so that the maximum flow rate of the heat carrier fluid is strictly less than 120% of the nominal flow rate. Similarly, a flow rate of the heat carrier fluid that is equal to or greater than 120% of the nominal flow rate can be said to be "excessive."

[0021] In particular embodiments, the device has the following features, taken alone or in combination where technically possible: the second cross-sectional expansion comprises a second tube; the second cross-sectional expansion includes a plurality of second tubes; The fluid circulator is designed so that the maximum flow rate of the heat-carrying fluid is greater than 150% of the nominal flow rate. -The fluid circulator is designed so that the maximum flow rate of the heat-carrying fluid is greater than 200% of the nominal flow rate. The thermal contact occurs in the condenser and the fluid circulator is the pump. The thermal contact occurs in the evaporator and the fluid circulator is a fan. The thermal contact occurs in the condenser and the fluid circulator is a fan. The thermal contact occurs in the evaporator and the fluid circulator is the pump.

[0022] The device according to the invention can be used in the following manner. The first and second machines are operated so as to actually exchange heat power between said first and second machines. The fluid circulator flows the heat-carrying fluid at an actual flow rate that is greater than 120% of the nominal flow rate.

[0023] The actual heat output exchanged by the second machine is determined by the actual flow rate multiplied by the actual change in enthalpy of the heat-carrying fluid. Due to the expansion and oversized circulator of the device, the actual heat output exceeds the nominal heat output.

[0024] The features, advantages, and other aspects of the present invention will become apparent from the following detailed description, which is given with reference to the accompanying drawings. [Brief explanation of the drawings]

[0025] [Figure 1] FIG. 1 is a schematic diagram of an example of an air / water heat pump (HP). [Figure 2] FIG. 1 is a schematic diagram of an example of an air / air conditioner (AC). DETAILED DESCRIPTION OF THE INVENTION

[0026] Specific embodiments of the proposed device will be described in detail below with reference to examples shown in the accompanying drawings, which illustrate the features and advantages of the invention, but do not limit the invention to these embodiments.

[0027] 1 is a schematic diagram of an air / water heat pump (HP), which comprises, in series, a compressor 5, a first branched expansion section 3, a condenser 2, a second expansion section 4, an expansion valve 6, and an evaporator 7 in a first pipe 8. In addition, a fluid circulator 1 in the form of a pump is provided in series in a second pipe 9 in thermal contact with the condenser 2.

[0028] 2 is a schematic diagram of an air / air air conditioner (AC), which includes, in series, a compressor 5, a first branched expansion section 3, a condenser 2, a second expansion section 4, an expansion valve 6, and an evaporator 7 in a first pipe 8. Furthermore, a second pipe 9 in thermal contact with the evaporator 7 is provided with a fan-type fluid circulator 10 in series with the second pipe 9.

[0029] The condenser and evaporator together are commonly referred to as the "heat exchanger" of the machine (HP or AC) throughout the application.

[0030] Referring to Figure 1, in a first embodiment, the present invention is realized in an air / water heat pump (i.e., HP) that takes energy from a cold source (i.e., outside air) and transfers it to a heat sink (i.e., water). Its practical application is to utilize the energy provided by the heat sink.

[0031] Such a vapor compression machine, as is known, comprises a compressor 5, a first branched expansion 3, a condenser 2, a second expansion 4, an expansion valve 6 and a first pipe 8 provided with an evaporator 7.

[0032] A second pipe 9, which is in thermal contact with the machine at one of the heat exchangers (in this example, the condenser 2), has a fluid circuit equipped with a fluid circulator (in this example, the pump 1) configured to circulate a heat-carrying fluid (in this example, water) through the second pipe 9.

[0033] Depending on the nominal heat output (in this example the heating power) of the heat pump, it is known to design the fluid circulator by calculations known from the prior art and detailed below.

[0034] JPEG2026504316000002.jpg28170

[0035] To meet the heating demand, each component of the HP (compressor, expansion valve, evaporator, and especially the condenser) is designed to provide the required heating power.

[0036] JPEG2026504316000003.jpg35170

[0037] JPEG2026504316000004.jpg29170

[0038] Table 1-1 shows theoretical values ​​calculated for an example air / water HP with a nominal output of 12 kW (i.e., nominal output when the outside air temperature is 7°C, the water temperature at the condenser inlet is 30°C, and the water temperature at the condenser outlet is 35°C) at three different water flow rates. [Table 1-1]

[0039] In this theoretical example, the temperature difference decreases inversely with the flow rate.

[0040] In the above example of an air / water HP with a nominal power output of 12 kW and a temperature change of the heat-carrying fluid at the inlet and outlet of the condenser (in accordance with the EN14511-2 standard) of 5 K, the nominal water flow rate is 0.57 kg / s. In the prior art, in this example, the fluid circulator is designed to achieve this nominal water flow rate.

[0041] The operating conditions for each of the experimental results in Tables 1-2 and 1-3 are the same, that is, an outside air temperature of 7°C and a water temperature of 35°C at the outlet of the condenser.

[0042] Table 1-2 shows the results of actual tests carried out on an unexpanded air / water HP designed with a nominal power output of 12 kW and operating with a refrigerant type R454C (mass composition: 21.5% R32, 78.5% R1234yf) at two different water flow rates. [Table 1-2]

[0043] Note that increasing the water flow rate does not result in an increase in the measured heating power, and therefore, a person skilled in the art would have no incentive to increase the flow rate of the heat-carrying fluid, i.e., the secondary fluid, of the fluid circulator above the nominal flow rate corresponding to a nominal power output of 12 kW (i.e., above 0.57 kg / s).

[0044] However, the inventors have discovered that in a HP according to the present invention operating with an extension and an oversized pump, increasing the flow rate of the secondary heat carrier fluid (in this example, the flow rate of water) unexpectedly increases the heating power. Indeed, while increasing the flow rate decreases the temperature difference, this temperature difference does not decrease inversely with the flow rate. The temperature decrease is smaller than expected.

[0045] Tables 1-3 show the results of tests carried out at four different water flow rates on an air / water HP according to the present invention with an expansion and oversized circulator, designed to have a nominal power of 12 kW and operating with a refrigerant of the R454C type. [Table 1-3]

[0046] In Table 1-3, Cases 2, 3 and 4 correspond to excessive flow rates that far exceed the nominal flow rate (0.57 kg / sec), while Case 1 corresponds to a flow rate that is fairly close to the nominal flow rate.

[0047] These results show that in a HP with an expansion section, increasing the flow rate unexpectedly decreases the temperature difference of the heat-carrying fluid non-proportionally, thus improving the heating power of the HP. The present invention takes advantage of this phenomenon by oversizing the fluid circulator, allowing the flow rate of the heat-carrying fluid to be much higher than the nominal flow rate, thereby achieving higher heating power.

[0048] In each instance of this first embodiment, the heat pump may be an air / air, air / water or water / water heat pump.

[0049] Referring to Figure 2, in a second embodiment, the present invention is realized in an air-to-air air conditioner (AC) that takes energy from a cold source (inside air) and transfers it to a heat sink (outside air). Its practical application is to utilize the energy available from the cold source.

[0050] The thermal machine has the same configuration as the first embodiment, except that in this second embodiment the second pipe 9 is in thermal contact with the other heat exchanger of the machine (in this example the evaporator 7), and a fluid circulator (i.e. fan 10) drives the refrigerant fluid, i.e. the secondary fluid (i.e. air), through the second pipe 9.

[0051] It is known to design a fluid circulator according to the following calculation depending on the nominal heat output (in this example, cooling power) of the air conditioner.

[0052] JPEG2026504316000008.jpg28170

[0053] To meet cooling demand, each component of the chiller (compressor, expansion valve, condenser and evaporator) is designed to provide the required cooling power.

[0054] JPEG2026504316000009.jpg28170

[0055] JPEG2026504316000010.jpg22170

[0056] Table 2-1 shows theoretical values ​​calculated for an example of an air / air air conditioner (AC) with a nominal output of 6.9 kW (i.e., nominal output when the outside air temperature is 35°C and the air temperature at the evaporator inlet is 27°C) at five different air flow rates. [Table 2-1]

[0057] In this theoretical example, the enthalpy difference decreases inversely with the flow rate.

[0058] The nominal flow rate of the secondary fluid is determined by the manufacturer depending on the intended use of the vapor compression thermodynamic machine. Typically, for residential air conditioning applications, a nominal flow rate is desired that will maintain a temperature difference of 10-15 K between the evaporator inlet and outlet. Typically, for commercial refrigeration applications, a nominal flow rate is desired that will maintain a temperature difference of 5-10 K between the evaporator inlet and outlet.

[0059] JPEG2026504316000012.jpg36170

[0060] The operating conditions for each experiment result in Tables 2-2 and 2-3 are the same, that is, an outside air temperature of 35°C and an air temperature at the inlet of the evaporator of 27°C.

[0061] Table 2-2 shows the results of actual tests carried out at two different air flow rates on the aforementioned air / air AC without expansion, designed to have a nominal power output of 6.9 kW and operating with a refrigerant of the type R410A (mass composition: 50% R32, 50% R125). [Table 2-2]

[0062] As expected, the measured cooling power is constant within experimental error, so a person skilled in the art has no incentive to increase the flow rate of the refrigerant, i.e., secondary fluid, in the fluid circulator beyond the nominal flow rate corresponding to a nominal power output of 6.9 kW (in this example, 0.5 kg / s according to the data sheet of the air conditioner used).

[0063] However, the inventors of the present invention have discovered that in an air conditioner according to the present invention operating with an extension and an oversized fan, increasing the flow rate of the refrigerant (in this example, the air flow rate) unexpectedly increases cooling power. In fact, as the flow rate increases, the enthalpy difference decreases, but this decrease does not decrease inversely with the flow rate. The decrease in enthalpy is less than expected.

[0064] Table 2-3 shows the results for four different air flow rates for an air / air AC according to the present invention with an expansion and oversized circulator, designed with a nominal power of 6.9 kW and operating with a refrigerant of type R410A. [Table 2-3]

[0065] In Table 2-3, Cases 2, 3 and 4 correspond to excessive flow rates that far exceed the nominal flow rate (0.5 kg / sec), while Case 1 corresponds to a flow rate that is quite close to the nominal flow rate.

[0066] The results obtained with the chiller according to the invention show that an increase in the flow rate surprisingly leads to a non-proportional decrease in the enthalpy difference ΔH of the refrigerant, and therefore to an increase in the cooling power. The invention takes advantage of this phenomenon by oversizing the fluid circulator, allowing the flow rate of the refrigerant to be much higher than the nominal flow rate, thereby obtaining a higher cooling power.

[0067] In each instance of this second embodiment, the air conditioner may be an air / air, air / water or water / water chiller.

[0068] The industrial applicability of the present invention is in the field of thermodynamic machines.

[0069] Throughout this application, the term "oversized" in reference to a fluid circulator or circuit is understood to refer to the size of the fluid circulator or circuit for a thermodynamic machine of the vapor compression type without expansion, having a certain nominal power output, which is usually provided by the manufacturer of the machine.

[0070] The teachings of this application equally apply to vapor compression type machines having the aforementioned extensions and in which the compressor is undersized relative to the fluid circulator, i.e., the secondary fluid circulator or exchanger (in which case the circulator is oversized relative to a vapor compression type thermodynamic machine).

[0071] That is, according to the present invention, when an expansion section is present, it is possible to undersize the compressor of a thermodynamic machine of the vapor compression type compared to the exchanger or fluid circulator of the thermodynamic machine, or to oversize the fluid circulator of the thermodynamic machine compared to the compressor or exchanger. Starting with a machine with a known nominal power output (typically provided by the machine manufacturer), the machine is operated at a fluid flow rate above the nominal flow rate by oversizing the fluid circulator, so that after the introduction of the expansion, it can be operated at an oversized flow rate and achieve a thermal output above the nominal power output. Starting with a machine with a given nominal heat output, if the fluid circulator is not changed and the compressor is undersized, the nominal heat output of the machine will be lower. The fluid flow rate through the unmodified fluid circulator will then be higher than the nominal flow rate calculated from the undersized compressor. This allows the original nominal heat output of the original fluid circulator to be extracted by a lower-power, usually cheaper compressor after the expansion is introduced.

[0072] Similarly, in the case of a system comprising a thermodynamic machine with a compressor and an expansion and another thermodynamic machine with a fluid circulator, the theoretical size of an appropriately sized fluid circulator and compressor pair without the expansion is calculated, and then the specifications of the circulator and compressor are checked and compared with the theoretical size of the pair to determine whether the circulator and compressor are relatively oversized. If the check is positive, the machine is a machine according to the present invention.

[0073] The teachings of the present application also extend to refrigerants other than those mentioned above (R410A and R454C), in particular R407C (mass composition: 50% R134a, 23% R32, 25% R125).

[0074] Unless otherwise specified, an extension in the sense of the present application may include one tube or multiple tubes.

Claims

1. a first thermodynamic machine of the vapor compression type through which a refrigerant circulates; a second thermodynamic machine through which a heat-carrying fluid circulates; An apparatus comprising: the first machine includes a compressor (5), a condenser (2), an expansion valve (6) and an evaporator (7) which together with the refrigerant determine the nominal heat output of the first machine; the second machine includes a fluid circulator (1, 10) configured to flow the heat-carrying fluid through the second machine so as to be in thermal contact with the refrigerant; a nominal heat output exchanged by the second machine is determined by a nominal flow rate multiplied by a predetermined change in enthalpy of the heat-carrying fluid; the fluid circulator (1, 10) is designed so that the maximum flow rate of the heat-carrying fluid is greater than 120% of the nominal flow rate; the first machine includes a first pipe extending widthwise across the internal cross section and lengthwise between the compressor (5) and the expansion valve (6) through the condenser (2); the first pipe has a first cross-sectional expansion (3) between the compressor (5) and the condenser (2); the first pipe has a second cross-sectional expansion (4) between the condenser (2) and the expansion valve (6); said first cross-sectional expansion (3) comprising a first inlet space of increasing cross-section, a first outlet space of decreasing cross-section, and a first tube fluidly connecting said first inlet space to said first outlet space; The second cross-sectional expansion (4) comprises a second inlet space of increasing cross-section, a second outlet space of decreasing cross-section, and at least one second tube fluidly connecting the second inlet space to the second outlet space.

2. 2. The device according to claim 1, wherein the second cross-sectional expansion (4) comprises a second tube.

3. 2. The device of claim 1, wherein the second cross-sectional expansion (4) comprises a plurality of second tubes.

4. 4. The device according to claim 1, wherein the fluid circulator (1, 10) is designed so that the maximum flow rate of the heat-carrying fluid is greater than 150% of the nominal flow rate.

5. 5. The device according to claim 4, wherein the fluid circulator (1, 10) is designed so that the maximum flow rate of the heat-carrying fluid is greater than 200% of the nominal flow rate.

6. 6. The device according to any one of claims 1 to 5, wherein the thermal contact occurs in the condenser (2) and the fluid circulator is a pump (1).

7. 6. The device according to any one of claims 1 to 5, wherein the thermal contact occurs in the evaporator (7) and the fluid circulator is a fan (10).

8. 6. The device according to any one of claims 1 to 5, wherein the thermal contact occurs in the condenser (2) and the fluid circulator is a fan.

9. 6. The device according to any one of claims 1 to 5, wherein the thermal contact occurs in the evaporator (7) and the fluid circulator is a pump.

10. the first machine and the second machine are operated to actually exchange heat power between the first machine and the second machine; the fluid circulator flows the heat-carrying fluid at an actual flow rate that is greater than 120% of the nominal flow rate; the actual heat output exchanged by the second machine is determined by the actual flow rate multiplied by the actual change in enthalpy of the heat-carrying fluid; 10. A method of using a device according to any one of claims 1 to 9, wherein the actual heat output exceeds the nominal heat output.

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