JP5345101B2 - Hot water heat source machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hot water heat source machine of high efficiency by ensuring necessary heating capacity without increasing a capacity of a low order-side refrigerating cycle. <P>SOLUTION: When an operational frequency of a low order-side compressor 11 becomes lower than a threshold value A, the opening of a low order-side expansion valve 15 is controlled so that a condensation temperature of a low order-side refrigerant in a low order-side condenser 14 becomes equal to a condensation temperature set value determined on the basis of the total efficiency, and when the operational frequency of the low order-side compressor 11 becomes higher than the threshold value A, the opening of the low order-side expansion valve 15 is controlled so that the condensation temperature of the low order-side refrigerant is increased according to the increase of the operational frequency of the low order-side compressor 11. <P>COPYRIGHT: (C)2012,JPO&amp;INPIT

Description

  The present invention relates to a hot water heat source machine that heats water using a dual refrigeration cycle.

  Conventionally, as a technique for generating high-temperature water using a refrigeration cycle, a technique of collecting heat from outside air using a binary refrigeration cycle and heating the hot water is used. The two-way refrigeration cycle can generate high-temperature water with high efficiency by using different refrigerants suitable for the temperature and pressure characteristics of the low-side refrigerant circuit and the high-side refrigerant circuit. When applying a dual refrigeration cycle to a hot water heat source machine, it is necessary to ensure the required heating capacity and perform high-efficiency operation throughout the heating period in accordance with the indoor heating load that fluctuates due to outside air conditions and the like.

  For example, in Patent Document 1, the high-end compressor is controlled so that the heating capacity calculated from the hot water temperature at the inlet / outlet of the heat exchanger becomes a set value, and the temperature of the intermediate heat exchanger becomes the temperature at which the efficiency becomes maximum. A technique for controlling the low-end compressor is disclosed.

JP-A-62-49160

  Usually, the heating capacity in a condition that maximizes the efficiency is lower than the maximum heating capacity that the hot water heat source machine can exhibit. However, according to Patent Document 1, since the low-side compressor is controlled so that the efficiency of the hot water heat source unit is maximized, the heating capacity of the low-side refrigeration cycle cannot be sufficiently obtained. Therefore, when the technique of Patent Document 1 is applied, it is necessary to increase the capacity of the low-source side refrigeration cycle in order to ensure the necessary heating capacity, resulting in an increase in the size of the hot water heat source machine and an increase in manufacturing cost. It will be.

  This invention is made | formed in view of the above, Comprising: It aims at ensuring a required heating capability, without enlarging the capacity | capacitance of a low-source side refrigerating cycle, and obtaining a hot water heat source apparatus as efficient as possible.

  In order to solve the above-described problems and achieve the object, the present invention provides a first evaporator that collects heat from outside air to gasify the first refrigerant, and a first pressure that boosts the gasified first refrigerant. A compressor, a first condenser that condenses the pressurized gaseous first refrigerant and extracts heat from the first refrigerant, and a first expansion valve that steps down the condensed first refrigerant are connected by piping. A first refrigeration cycle formed by the second evaporator, a second evaporator that gasifies the second refrigerant using heat extracted from the first condenser, and a second compression that pressurizes the gasified second refrigerant A second condenser that condenses the pressurized gaseous second refrigerant and extracts heat from the second refrigerant, and a second expansion valve that lowers the pressure of the condensed second refrigerant are connected by piping. The formed second refrigeration cycle and the heat extracted from the second condenser. A hot water generation system comprising a hot water heat exchanger for raising the temperature of the water, the control unit for controlling the first refrigeration cycle, the second refrigeration cycle, and the hot water generation system, and the first condenser in the first condenser Condensation temperature detection means for detecting the condensation temperature of the first refrigerant, and discharge water temperature detection means for detecting the temperature of the water discharged by the hot water heat exchanger, the control unit is detected by the discharge water temperature detection means A heating capacity controller that increases or decreases the operating frequency of the first compressor so that the measured temperature is equal to a water temperature set value, and when the operating frequency of the first compressor falls below a predetermined threshold, The opening of the first expansion valve is controlled so that the condensation temperature of the first refrigerant in the condenser is equal to a condensation temperature set value determined based on the overall efficiency, and the operating frequency of the first compressor is When the threshold is exceeded Characterized by comprising a, an expansion valve control unit the condensation temperature of the first refrigerant controls the opening of the first expansion valve so as to increase in accordance with increase of the operation frequency.

  According to the present invention, it is possible to switch between performing an operation that prioritizes the efficiency of the heat source unit or performing an operation that prioritizes securing the necessary heating capacity according to the required heating capacity. There is an effect that it is possible to secure a necessary heating capacity without increasing the size and to obtain a hot water heat source as highly efficient as possible.

FIG. 1 is a block diagram showing the configuration of the hot water heat source machine. FIG. 2 is a diagram illustrating a functional configuration of the control unit. FIG. 3 is a diagram showing the relationship between the operating frequency of the low-side compressor and the operating frequency of the high-side compressor determined by the frequency setting function. FIG. 4 is a diagram showing the relationship between the operating frequency of the low-side compressor and the operating frequency of the high-side compressor determined by the frequency setting function. FIG. 5 is a graph showing the relationship between the low-side condensation temperature and the heat source efficiency. FIG. 6 is a diagram illustrating the relationship between the low-source-side condensation temperature and the high-source-side heating capacity. FIG. 7 is a diagram showing the relationship between the operating frequency of the low-side compressor and the condensing temperature setting value obtained from the condensing temperature setting function. FIG. 8 is a diagram showing the relationship between the operating frequency of the low-end compressor and the condensing temperature setting value for each different hot water temperature setting value. FIG. 9 is a flowchart for explaining the operation of the control unit. FIG. 10 is a flowchart for explaining the operation of the control unit.

  Hereinafter, embodiments of a hot water heat source apparatus according to the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment.
FIG. 1 is a block diagram showing a configuration of a hot water heat source apparatus according to an embodiment of the present invention. As shown in the figure, the hot water heat source apparatus 100 includes a low-source side refrigeration cycle 1, a high-source side refrigeration cycle 2, a hot water circulation cycle 3, and a control unit 5. The hot water heat source device 100 is used in combination with the radiator 4 that heats the room using the heat of hot water circulating in the hot water circulation cycle 3.

  The low-source-side refrigeration cycle 1 includes a low-source-side compressor 11, a low-source-side four-way valve 12, a low-source-side condenser 14, a low-source-side expansion valve 15, and a low-source-side evaporator 13, which are sequentially connected by piping. Has been configured. A refrigerant (low-source side refrigerant) circulates in the piping of the low-source side refrigeration cycle 1. Further, the low-side refrigeration cycle 1 includes a low-side discharge refrigerant temperature detecting means 16 for detecting the discharge refrigerant temperature of the low-side compressor 11 and a condensation temperature of the refrigerant condensed in the low-side condenser 14 (low-side side). The low-side condenser refrigerant temperature detecting means 17 for detecting the (condensation temperature) is provided.

  The high-side refrigeration cycle 2 includes a high-side compressor 21, a high-side four-way valve 22, a high-side condenser 24, a high-side expansion valve 25, and a high-side evaporator 23, which are sequentially connected by piping. Has been configured. A refrigerant (high-side refrigerant) circulates in the piping of the high-side refrigeration cycle 2. The high-end side refrigeration cycle 2 includes a high-end side discharge refrigerant temperature detecting means 26 that detects the discharge refrigerant temperature of the high-end side compressor 21, and a condensation temperature (high-end side) of the refrigerant condensed in the high-end side condenser 24. A high-side condenser refrigerant temperature detecting means 27 for detecting a condensing temperature) is provided.

  The low original side condenser 14 of the low original side refrigeration cycle 1 and the high original side evaporator 23 of the high original refrigeration cycle 2 are connected to each other so as to be able to exchange heat, and function as the intermediate heat exchanger 6.

  The hot water circulation cycle 3 includes a tank 33, a hot water circulation means 31, and a hot water heat exchanger 32, which are sequentially connected by piping. A hot water temperature detecting means 34 for detecting the temperature of the hot water discharged from the hot water heat exchanger 32 is disposed at the outlet of the hot water heat exchanger 32. The hot water heat exchanger 32 is connected to the condenser 24 of the high-side refrigeration cycle 2 so as to be able to exchange heat. The radiator 4 is pipe-connected to the hot water circulation cycle 3 and is disposed indoors. The temperature of the hot water is radiated from the radiator 4 into the room, thereby heating the room.

  In the low source side refrigeration cycle 1, the refrigerant is circulated by the low source side compressor 11. In the low-source side refrigeration cycle 1, the refrigerant that has been deprived of heat by the low-source side condenser 14 and condensed and liquefied becomes a low-temperature and low-pressure gas-liquid two-phase state by the low-source side expansion valve 15. The heat is collected from the outside air, evaporated, becomes a low-temperature and low-pressure gas state, is compressed by the low-side compressor 11 and becomes a high-temperature and high-pressure gas refrigerant, and is again deprived of heat by the low-side condenser 14 to condense and liquefy. Repeat cycle.

  In the high-source side refrigeration cycle 2, similarly to the low-source side refrigeration cycle 1, the refrigerant is circulated by the high-source side compressor 21. The refrigerant that has been deprived of heat by the high-end side condenser 24 and condensed and liquefied becomes a low-temperature and low-pressure gas-liquid two-phase state at the high-side expansion valve 25, and the low-side side refrigeration cycle 1 in the high-side evaporator 23. A cycle in which heat is collected from the refrigerant, evaporated, and converted into a low-temperature and low-pressure gas state, compressed by the high-side compressor 21 to become a high-temperature and high-pressure gas refrigerant, and again deprived of heat by the high-side condenser 24 to be condensed and liquefied. repeat.

  The operation frequency of the low-side compressor 11 and the high-side compressor 21 is configured to be variable, and it is possible to adjust the circulation amount of the refrigerant by changing the rotation speed according to the operation frequency. In addition, the opening of the low-side expansion valve 15 and the high-side expansion valve 25 is adjusted, and the amount of refrigerant circulating in the refrigeration cycle, the temperature of refrigerant discharged from the compressor, and the temperature of refrigerant condensed in the condenser are controlled. To do.

  In the hot water circulation cycle 3, hot water is circulated by the hot water circulation means 31. In the hot water circulation cycle 3, heat is collected from the refrigerant of the high-end refrigeration cycle 2 by the hot water heat exchanger 32 to heat the hot water. The heated warm water is conveyed to the radiator 4 by the warm water circulation means 31, dissipated by the radiator 4, and is sent to the warm water heat exchanger 32 again via the tank 33.

  Low original side refrigerant temperature detection means 16, low original condenser temperature detection means 17, high original discharge refrigerant temperature detection means 26, high original condenser refrigerant temperature detection means 27, and hot water temperature detection means 34 Each of the temperatures is sent to the control unit 5. The control unit 5 controls the low-source side refrigeration cycle 1, the high-source side refrigeration cycle 2, and the hot water circulation cycle 3 based on the received temperature. Further, the control unit 5 may measure the operation time of the low-source side refrigeration cycle 1, the high-source side refrigeration cycle 2, and the hot water circulation cycle 3 by a timing unit (not shown).

  FIG. 2 is a diagram illustrating a functional configuration of the control unit 5. As illustrated, the control unit 5 includes a heating capacity control unit 51, an expansion valve control unit 52, and a function storage area 53. The control unit 5 is realized by executing a control program in hardware of a normal computer configuration including a CPU, a ROM (Read Only Memory), and a RAM (Random Access Memory). The control program is stored in the ROM, read from the ROM at the time of startup, and expanded in a program expansion area on the RAM. The CPU functions as the heating capacity control unit 51 and the expansion valve control unit 52 by executing the control program developed in the program development area. The function storage area 53 is configured by a ROM or a RAM.

  When the operating frequency of the low-side compressor 11 increases, the amount of refrigerant circulating in the low-side refrigeration cycle 1 increases, and the amount of heat collected by the low-side evaporator 13 increases. Further, when the operating frequency of the low-side compressor 11 is lowered, the amount of refrigerant circulating in the low-side refrigeration cycle 1 is reduced, and the amount of heat collected by the low-side evaporator 13 is reduced. That is, the heating capacity of the hot water heat source apparatus 100 mainly depends on the operating frequency of the low-source compressor 11. The heating capacity control unit 51 operates the hot water circulation means 31 and sets the operating frequency of the low-source compressor 11 so that the temperature detected by the hot water temperature detection means 34 becomes equal to the set temperature of the hot water (hot water temperature set value). Manipulate.

  Further, the heating capacity control unit 51 changes the operation frequency of the high-side compressor 21 according to the operation frequency of the low-side compressor 11. The operating frequency of the high-side compressor 21 is set as a function of the operating frequency of the low-side compressor 11 (frequency setting function 54). The frequency setting function 54 is stored in the function storage area 53 in advance.

  FIG. 3 is a diagram showing the relationship between the operating frequency of the low-source side compressor 11 and the operating frequency of the high-side compressor 21 obtained by the frequency setting function 54. In the intermediate heat exchanger 6, the amount of heat given from the low source side refrigeration cycle 1 and the amount of heat obtained by the high source side refrigeration cycle 2 are the same, so the operating frequency of the low source side compressor 11 is increased and the low source side refrigeration cycle is increased. When the amount of heat applied from 1 is increased, the heating capacity control unit 51 increases the operating frequency of the high-side compressor 21 based on the above function, and increases the amount of heat obtained by the high-side refrigeration cycle 2. By increasing the operating frequency of the high-end side compressor 21, the amount of refrigerant circulating in the high-end side refrigeration cycle 2 increases, and the heating capacity in the hot water heat exchanger 32 increases.

  Conversely, when the operating frequency of the low-side compressor 11 is lowered and the amount of heat given from the low-side refrigeration cycle 1 is reduced, the heating capacity control unit 51 lowers the operating frequency of the high-side compressor 21 and increases the heat The amount of heat obtained by the original refrigeration cycle 2 is reduced. By reducing the operating frequency of the high-source side compressor 21, the amount of refrigerant circulating in the high-side refrigeration cycle 2 is reduced, and the heating capacity in the hot water heat exchanger 32 is reduced. In FIG. 3, the relationship between the operating frequency of the low-source compressor 11 and the operating frequency of the high-source compressor 21 is in a proportional relationship, but is not necessarily in a proportional relationship. Simplification may be achieved.

  The heating capacity control unit 51 also executes switching control of the circuits of the low-source side four-way valve 12 and the high-source side four-way valve 22.

  The expansion valve control unit 52 controls the condensation temperatures in the low-side condenser 14 and the high-side condenser 24 by adjusting the opening degrees of the low-side expansion valve 15 and the high-side expansion valve 25.

  More specifically, in the expansion valve control unit 52, the low-side condenser temperature detected by the low-side condenser refrigerant temperature detecting means 17 of the low-side condenser 14 becomes a target value (condensation temperature set value). In this way, the opening degree of the low-side expansion valve 15 is controlled. The expansion valve control unit 52 calculates a condensing temperature setting value based on a function (condensing temperature setting function 55) of the operating frequency of the low-source compressor 11 and the hot water temperature setting value. The condensation temperature setting function 55 is stored in advance in the function storage area 53.

  FIG. 5 is a diagram showing the relationship between the low-side condensation temperature and the heat source machine efficiency (total efficiency). The efficiency of the hot water heat source device 100 is affected by the low-side condensation temperature. The condensation temperature has a condensation temperature at which the efficiency of the heat source machine is maximized. In addition, the condensation temperature at which the efficiency of the heat source machine is maximized varies depending on the generated hot water temperature. For example, when the generated hot water temperature is 70 ° C., the condensation temperature is 30 ° C.

  FIG. 6 is a diagram illustrating a relationship between the low-side condensation temperature and the high-side heating capacity. The high-source-side heating capacity increases as the low-source-side condensation temperature increases. This is because the amount of heat that the high-source side refrigeration cycle 2 obtains from the intermediate heat exchanger 6 increases as the low-source-side condensation temperature increases.

  FIG. 7 is a diagram illustrating the relationship between the operating frequency of the low-compressor compressor 11 and the condensing temperature setting value obtained by the condensing temperature setting function 55. The expansion valve control unit 52 makes the condensing temperature set value constant in a range where the operating frequency of the low-side compressor 11 is A or less, and when the operating frequency of the low-side compressor 11 exceeds A, the low-side compressor 11 As the operating frequency of the side compressor 11 increases, the condensation temperature set value is increased. The condensation temperature set value in the range where the operation frequency of the low-side compressor 11 is A or less is set to a condensation temperature (for example, 30 ° C.) at which the heat source machine efficiency is maximized.

  The operating frequency A of the low-side compressor 11 that is the threshold value is an upper limit operating frequency that can ensure the necessary heating capacity at the condensation temperature at which the heat source efficiency is maximized. As described above, since the high-source side heating capacity increases as the operating frequency of the low-side compressor 11 increases, it is determined that the required heating capacity is large in a state where the operating frequency of the low-source compressor 11 is high. it can. In order to operate so that the efficiency of the heat source machine is maximized, it is only necessary to operate at the condensation temperature at which the efficiency is always the maximum (that is, the condensation temperature set value determined based on the overall efficiency). If the operating frequency is high and the required heating capacity is large, priority should be given to securing the heating capacity over the efficiency of the heat source machine, so the condensing temperature setting value is set higher than the maximum condensing temperature. .

  FIG. 8 is a diagram showing the relationship between the operating frequency of the low-source compressor 11 and the condensing temperature setting value for each different hot water temperature setting value. Since the condensing temperature at which the heat source device efficiency is maximized varies depending on the generated hot water temperature, the condensing temperature setting value is changed according to the hot water temperature setting value as shown in the figure.

  Similarly, the opening degree of the high-side expansion valve 25 is controlled so that the refrigerant condensing temperature detected by the high-side condenser refrigerant temperature detecting means 27 of the high-side condenser 24 becomes a set value. The target refrigerant condensing temperature is set as a function of the generated hot water temperature and the operating frequency of the high-end compressor 21, and the expansion valve control unit 52 determines the high-end side condenser 24 based on the function. Find the target condensation temperature for the refrigerant. The function is stored in advance in the function storage area 53 (not shown). Since the concept of the target condensation temperature is the same as in the case of the low-source side expansion valve 15, detailed description thereof is omitted here.

  Next, the operation of the hot water heat source apparatus 100 according to the embodiment of the present invention will be described. FIG. 9 is a flowchart for explaining the operation of the control unit 5. When the operation start operation is performed, the heating capacity control unit 51 first operates the hot water circulation means 31, and operates the low-side compressor 11 and the high-side compressor 21 at a predetermined operating frequency (step S1). . And the heating capability control part 51 determines whether the warm water temperature detected by the warm water temperature detection means 34 is lower than the set warm water temperature setting value (step S2), and the detected warm water temperature is the warm water temperature. When lower than the set value (step S2, Yes), the operating frequency of the low-end compressor 11 is increased (step S3), and when the detected hot water temperature is higher than the hot water temperature set value (step S2, No), The operating frequency of the low source side compressor 11 is lowered (step S4). The heating capacity control unit 51 also changes the operating frequency of the high-side compressor 21 based on the frequency setting function 54 when the operating frequency of the low-side compressor 11 is changed.

  As described above, when the heating capacity is insufficient with respect to the required heating capacity, the heating capacity control unit 51 controls to increase the operation frequency of the low-source compressor 11, and when the heating capacity is excessive, In addition to controlling the operating frequency of the low-side compressor 11 to decrease, the operating frequency of the high-side compressor 21 is controlled to be a value set in advance as a function of the operating frequency of the low-side compressor 11. Thus, it becomes possible to ensure the necessary heating capacity against the varying heating load. That is, the required heating capacity can be ensured without increasing the capacity of the low-source side refrigeration cycle.

  After step S3 or step S4, the expansion valve control unit 52 obtains the low-side condensing temperature set value based on the condensing temperature setting function 55 (step S5), and the low-side condensing refrigerant temperature detecting means 17 detects it. The opening degree of the low-side expansion valve 15 is adjusted so that the low-side condensation temperature to be equalized with the determined condensation temperature set value (step S6). Then, the process proceeds to step S2. The expansion valve control unit 52 also adjusts the opening degree of the high-side expansion valve 25 when the opening degree of the low-side expansion valve 15 is adjusted.

  FIG. 10 is a flowchart for explaining the operation of the controller 5 when the hot water temperature set value is changed. As shown in the figure, when the hot water temperature set value is changed (step S11), the expansion valve control unit 52 obtains the low-side condensing temperature set value based on the condensing temperature setting function 55 (step S12). The opening degree of the low-side expansion valve 15 is adjusted so that the low-side condensation temperature detected by the original-side condenser refrigerant temperature detection means 17 becomes equal to the determined condensation temperature set value (step S13). The operation when the hot water temperature set value is changed is a return.

  As described above, according to the embodiment of the present invention, the control unit 5 increases or decreases the operating frequency of the low-side compressor 11 so that the temperature detected by the hot water temperature detection means 34 is equal to the hot water temperature set value. When the operating frequency of the heating capacity control unit 51 and the low-side compressor 11 is below the threshold value A, the condensation temperature of the low-side refrigerant in the low-side condenser 14 is determined based on the overall efficiency. When the opening of the low-side expansion valve 15 is controlled to be equal to the temperature set value and the operating frequency of the low-side compressor 11 exceeds the threshold value A, the condensation temperature of the low-side refrigerant is low. And the expansion valve control unit 52 that controls the opening degree of the low-side expansion valve 15 so as to increase in accordance with the increase in the operating frequency of the side compressor 11. Rather than operating for efficiency, depending on the required heating capacity Since it is possible to switch between the operation that prioritizes the efficiency of the heat source unit or the operation that prioritizes the required heating capacity, the necessary heating capacity can be secured without increasing the capacity of the low-source side refrigeration cycle, and It will be possible to operate as efficiently as possible.

  Further, since the threshold value A and the condensation temperature set value are determined for each hot water temperature set value, the threshold value A and the condensation temperature set value can be set finely, so that the efficiency of the heat source machine can be further increased. .

  The low temperature side condenser refrigerant temperature detection means 17 and the high temperature side condenser refrigerant temperature detection means 27 detect the condensation temperature and the low voltage side discharge refrigerant temperature detection means 16 and the high voltage side discharge refrigerant temperature detection means 26 detect. There is a correlation with the discharge temperature. In the above description, the low-side expansion valve 15 and the high-side expansion valve 25 are opened based on the condensation temperatures detected by the low-side condenser refrigerant temperature detection unit 17 and the high-side condenser refrigerant temperature detection unit 27. The degree of opening of the expansion valves 15 and 25 is determined based on the discharge temperature detected by the low-end side discharge refrigerant temperature detection means 16 and the high-end side discharge refrigerant temperature detection means 26 instead of the condensation temperature. You may make it control. By doing in this way, even when the condensation temperature cannot be detected as in the case where the intermediate heat exchanger 6 and the hot water heat exchanger 32 are plate-type heat exchangers, the control based on the condensation temperature can be performed. Equivalent control can be performed. More specifically, when the operating frequency of the low-side compressor 11 falls below a predetermined threshold value, the expansion valve control unit 52 sets the discharge temperature at which the low-side discharge temperature is determined based on the overall efficiency. When the opening of the low-side expansion valve 15 is controlled to be equal to the set value, and the operating frequency of the low-side compressor 11 exceeds the threshold value, the low-side discharge temperature is low The opening degree of the low-side expansion valve 15 may be controlled so as to increase in accordance with an increase in the operating frequency of the machine 11. By doing so, the required heating capacity can be ensured without increasing the capacity of the low-source side refrigeration cycle, and the operation can be performed as efficiently as possible.

  Further, even when the opening degree of the low-side expansion valve 15 is controlled based on the discharge temperature, the operation frequency for determining whether to perform the operation giving priority to the efficiency or the operation for securing the heating capacity is performed. The set values of the threshold value and the discharge temperature may be determined for each hot water temperature set value. By doing in this way, since the set value of the said threshold value and discharge temperature can be set finely, the efficiency of a heat source machine can further be improved.

  As described above, the hot water heat source apparatus according to the present invention is suitable for application to a hot water heat source apparatus that heats water using a dual refrigeration cycle.

DESCRIPTION OF SYMBOLS 1 Low original side refrigerating cycle 2 High original side refrigerating cycle 3 Hot water circulation cycle 4 Radiator 5 Control part 6 Intermediate heat exchanger 11 Low original side compressor 12 Low original side four-way valve 13 Low original side evaporator 14 Low original side condensation 15 Low original side expansion valve 16 Low original side discharge refrigerant temperature detecting means 17 Low original side condenser refrigerant temperature detecting means 21 High high side compressor 22 High high side four-way valve 23 High high side evaporator 24 High high side condenser 25 High-end expansion valve 26 High-end discharge refrigerant temperature detection means 27 High-end condenser refrigerant temperature detection means 31 Hot water circulation means 32 Hot water heat exchanger 33 Tank 34 Hot water temperature detection means 51 Heating capacity control unit 52 Expansion valve control Section 53 Function storage area 54 Frequency setting function 55 Condensation temperature setting function 100 Hot water heat source machine

Claims (5)

A first evaporator that collects heat of outside air to gasify the first refrigerant, a first compressor that pressurizes the gasified first refrigerant, and condenses the pressurized gaseous first refrigerant to A first refrigeration cycle formed by connecting a first condenser for extracting heat from the first refrigerant and a first expansion valve for reducing the pressure of the condensed first refrigerant;
A second evaporator configured to gasify a second refrigerant using heat extracted from the first condenser; a second compressor configured to pressurize the gasified second refrigerant; and the pressurized gaseous second A second refrigeration cycle formed by connecting a second condenser for condensing the refrigerant to extract heat from the second refrigerant and a second expansion valve for reducing the pressure of the condensed second refrigerant;
A hot water generating system comprising a hot water heat exchanger that raises the temperature of the water using the heat extracted from the second condenser;
A control unit for controlling the first refrigeration cycle, the second refrigeration cycle, and the hot water generation system;
Condensing temperature detecting means for detecting the condensing temperature of the first refrigerant in the first condenser;
Discharge water temperature detection means for detecting the temperature of the water discharged by the hot water heat exchanger,
With
The controller is
A heating capacity controller that increases or decreases the operating frequency of the first compressor so that the temperature detected by the discharge water temperature detection means is equal to a water temperature set value;
When the operating frequency of the first compressor falls below a predetermined threshold, the condensing temperature of the first refrigerant in the first condenser is equal to a condensing temperature setting value determined based on total efficiency. When the opening of the first expansion valve is controlled and the operating frequency of the first compressor exceeds the threshold value, the condensing temperature of the first refrigerant increases so as to increase as the operating frequency increases. An expansion valve controller for controlling the opening of the first expansion valve;
A hot water heat source machine comprising:   The hot water heat source apparatus according to claim 1, wherein the predetermined threshold value and the condensing temperature set value are determined for each water temperature set value. A first evaporator that collects heat of outside air to gasify the first refrigerant, a first compressor that pressurizes the gasified first refrigerant, and condenses the pressurized gaseous first refrigerant to A first refrigeration cycle formed by connecting a first condenser for extracting heat from the first refrigerant and a first expansion valve for reducing the pressure of the condensed first refrigerant;
A second evaporator configured to gasify a second refrigerant using heat extracted from the first condenser; a second compressor configured to pressurize the gasified second refrigerant; and the pressurized gaseous second A second refrigeration cycle formed by connecting a second condenser for condensing the refrigerant to extract heat from the second refrigerant and a second expansion valve for reducing the pressure of the condensed second refrigerant;
A hot water generating system comprising a hot water heat exchanger that raises the temperature of the water using the heat extracted from the second condenser;
A control unit for controlling the first refrigeration cycle, the second refrigeration cycle, and the hot water generation system;
Discharge refrigerant temperature detection means for detecting the temperature of the first refrigerant discharged by the first compressor;
Discharge water temperature detection means for detecting the temperature of the water discharged by the hot water heat exchanger,
With
The controller is
A heating capacity controller that increases or decreases the operating frequency of the first compressor so that the temperature detected by the discharge water temperature detection means is equal to a water temperature set value;
When the operating frequency of the first compressor falls below a predetermined threshold, the temperature of the first refrigerant discharged from the first compressor is equal to the refrigerant temperature set value determined based on the overall efficiency. When the opening of the first expansion valve is controlled and the operating frequency of the first compressor exceeds the threshold value, the temperature of the first refrigerant discharged from the first compressor responds to an increase in the operating frequency. An expansion valve control unit for controlling the opening of the first expansion valve so as to increase,
A hot water heat source machine comprising:   The hot water heat source apparatus according to claim 3, wherein the predetermined threshold value and the refrigerant temperature set value are determined for each water temperature set value. The heating capacity control unit increases or decreases the operating frequency of the second compressor according to the increase or decrease of the operating frequency of the first compressor.
The hot water heat source machine according to any one of claims 1 to 4, wherein

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