JP2007192499A - Hot water supply device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hot water supply device having an improved coefficient of performance (COP) by operating a heat pump in a more optimal condition. <P>SOLUTION: An environment load Qk is computed in accordance with external conditions depending on an outside air temperature Ta and an incoming water temperature Twi, and a target rotating number RN of a compressor 11 is set properly corresponding to a value for the found environment load Qk. Particularly, as the outside air temperature Ta is lower or as the incoming water temperature Twi is higher, the target rotating number RN of the compressor 11 is set to be a higher value. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a hot water supply apparatus using a heat pump as a heat source.

  This type of hot water supply apparatus includes a heat pump having a compressor, a heat exchanger, an expansion valve, and an evaporator, a hot water storage tank, and a water supply pump. The heat exchanger of the heat pump is for exchanging heat between the refrigerant and water (including low temperature hot water), and the water inlet of the heat exchanger is connected to the lower part of the hot water storage tank via the water supply pump. The outlet is connected to the upper part of the hot water storage tank.

Recently, in order to operate the hot water supply device in an optimum state, the rotation speed control of the compressor, the opening degree control of the expansion valve, and the rotation speed control of the feed water pump are performed based on the outside air temperature detected by the outside air temperature detection sensor. A water heater has been proposed.
Japanese Patent No. 3601369

  In the hot water supply apparatus, the compressor, the expansion valve, and the water supply pump are controlled based only on the outside air temperature. However, in practice, it is difficult to operate the heat pump in an optimum state.

  That is, the hot water supply device is configured to send the water in the hot water storage tank to the heat exchanger by the operation of the water supply pump to heat it, and to send the heated hot water to the hot water storage tank. The coefficient of performance (COP) varies. In other words, if the compressor, expansion valve, and feed water pump are controlled in consideration of not only the outside air temperature but also the temperature at which water enters the heat exchanger, the heat pump is operated in a more optimal state and the coefficient of performance (COP) is improved. Can be achieved.

  The present invention was created in view of the above circumstances, and the object of the present invention is to provide a hot water supply apparatus capable of operating a heat pump in a more optimal state to improve the coefficient of performance (COP). is there.

  In order to achieve the above object, a hot water supply apparatus of the present invention includes a compressor capable of controlling the number of rotations, a heat pump including at least a heat exchanger that performs heat exchange between the refrigerant and water, and a lower portion with a water inlet of the heat exchanger. A hot water storage tank connected to the hot water outlet of the heat exchanger, a water supply pump for feeding water in the hot water storage tank to the heat exchanger, and an outside air temperature sensor for detecting the outside air temperature, The water temperature sensor for detecting the temperature of water entering the heat exchanger and the heat pump operation, the lower the outside air temperature or the higher the incoming water temperature based on the detected outside air temperature and the incoming water temperature, It is characterized by comprising compressor control means for controlling the rotational speed to be high.

  According to this hot water supply apparatus, as the outside air temperature becomes lower or the incoming water temperature becomes higher, the higher target rotational speed is set in the compressor. Therefore, as compared with the case where the compressor is controlled based only on the outside air temperature. The coefficient of performance (COP) can be improved by operating the heat pump in a more optimal state.

  Further, the hot water supply apparatus of the present invention includes a heat pump that exchanges heat between the compressor, the refrigerant, and water, a heat pump that includes at least an expansion valve capable of opening control, and a lower portion connected to a water inlet of the heat exchanger. A hot water storage tank whose upper part is connected to the outlet of the heat exchanger, a water supply pump for sending water in the hot water storage tank to the heat exchanger, an outdoor air temperature sensor for detecting the outdoor air temperature, An incoming water temperature sensor for detecting the incoming water temperature to the exchanger, a discharge temperature sensor for detecting the refrigerant discharge temperature from the compressor, a hot water temperature setting device for setting the hot water temperature, and during heat pump operation Based on the detected outside air temperature, incoming water temperature and discharge temperature, and set hot water temperature, the lower the outdoor air temperature, the higher incoming water temperature, or the higher the set hot water temperature, the higher the discharge temperature of the compressor. And a expansion valve control means for controlling the opening degree of the expansion valve such that, as its characterized in that.

  According to this hot water supply device, the opening degree change amount of the expansion valve is set so that the discharge temperature of the compressor becomes higher as the outside air temperature becomes lower, the incoming water temperature becomes higher, or the set hot water temperature becomes higher. Therefore, the coefficient of performance (COP) can be improved by operating the heat pump in a more optimal state as compared with the case where the expansion valve is controlled based only on the outside air temperature.

  Furthermore, the hot water supply apparatus of the present invention includes a heat pump including at least a heat exchanger that performs heat exchange between the compressor, the refrigerant, and water, a lower part connected to a water inlet of the heat exchanger, and an upper part for heat exchange. To the hot water storage tank connected to the hot water outlet of the water heater, the water supply pump capable of controlling the number of revolutions for feeding the water in the hot water storage tank to the heat exchanger, the outside air temperature sensor for detecting the outside air temperature, and the heat exchanger Incoming water temperature sensor for detecting the incoming water temperature, outgoing hot water temperature setting device for setting the outgoing hot water temperature, and during heat pump operation, the higher the outdoor air temperature is based on the detected outdoor air temperature, incoming water temperature and the set outgoing hot water temperature. Alternatively, it is characterized by comprising pump control means for controlling so that the rotation speed of the feed water pump becomes higher as the incoming water temperature becomes higher or the set hot water temperature becomes lower.

  According to this hot water supply apparatus, the higher the outside air temperature, the higher the incoming water temperature, or the lower the set hot water temperature, the higher the rotational speed is set in the water supply pump. Compared with the case of controlling the feed water pump, the coefficient of performance (COP) can be improved by operating the heat pump in a more optimal state.

  According to the present invention, the coefficient of performance (COP) can be improved by operating the heat pump in a more optimal state as compared with the case where the compressor, the expansion valve, and the feed water pump are controlled based only on the outside air temperature. it can.

  The above object and other objects, structural features, and operational effects of the present invention will become apparent from the following description and the accompanying drawings.

  1 to 11 show an embodiment of the present invention. 1 is a circuit configuration diagram of a hot water supply apparatus, FIG. 2 is a control system diagram of the hot water supply apparatus shown in FIG. 1, FIG. 3 is a flowchart showing a first operation method realized by the hot water supply apparatus shown in FIG. FIG. 5 is a data table according to the first operation method, FIG. 7 is a flowchart showing a second operation method realized by the hot water supply apparatus shown in FIG. 1, and FIGS. 8 and 9 are data according to the second operation method. FIG. 10 is a flowchart showing a third operation method realized by the hot water supply apparatus shown in FIG. 1, and FIG. 11 is a data table according to the third operation method.

  First, the circuit configuration of the hot water supply apparatus will be described with reference to FIG. The hot water supply device shown in FIG. 1 includes a heat pump unit 10 and a tank unit 20.

The heat pump unit 10 includes a variable capacity compressor 11 that can control the number of revolutions, a heat exchanger 12 that performs heat exchange between the refrigerant and water (including low-temperature hot water), and an electronic device that can control the opening. A heat pump HP having at least an expansion valve 13, an evaporator 14, and a blower 15 for the evaporator is provided. The heat pump HP uses carbon dioxide (CO ₂ ) as a refrigerant. In addition, an outside air temperature sensor 16 for detecting the outside air temperature Ta is provided in the evaporator 14 or the vicinity thereof, and a tapping temperature Two from the heat exchanger 12 is set at or near the outlet 12a of the heat exchanger 12. An outlet hot water temperature sensor 17 is provided for detection, and an incoming water temperature sensor 18 for detecting an incoming water temperature Twi to the heat exchanger 12 is provided at or near the inlet 12b of the heat exchanger 12, and a compressor. A discharge temperature sensor 19 for detecting the discharge temperature Td of the refrigerant from the compressor 11 is provided at or near the 11 discharge ports 11a.

  The tank unit 20 includes a hot water storage tank 21 capable of storing a predetermined amount of hot water or hot water and water in a full state, and a water supply pump 22 capable of controlling the rotation speed. The water inlet 12b of the heat exchanger 12 of the heat pump HP is connected to the lower part of the hot water storage tank 21 via a pipe line WP1 provided with a water supply pump 22, and the hot water outlet 12a is connected to the upper part of the hot water storage tank 21 via a pipe line WP2. It is connected. A pipe WP3 for taking water CW into the hot water storage tank 21 is connected to the lower part of the hot water storage tank 21, and a pipe WP4 for sending hot water HW from the hot water storage tank 21 to the upper part of the hot water storage tank 21. Is connected.

  In the hot water supply apparatus shown in FIG. 1, the heat pump HP is operated, and the water supply pump 22 is operated to feed water (including low temperature hot water) in the hot water storage tank 21 to the heat exchanger 12 of the heat pump HP. The water can be heated by the refrigerant heat and fed into the hot water storage tank 21.

  Next, the control system of the hot water supply apparatus shown in FIG. 1 will be described with reference to FIG. The control system shown in FIG. 2 includes a main control circuit 31, a compressor drive circuit 32, an expansion valve drive circuit 33, a blower drive circuit 34, a pump drive circuit 35, and a tapping temperature setting device 36.

  The main control circuit 31 has a microcomputer configuration, and stores programs related to compressor control, expansion valve control, and pump control, which will be described later, data necessary for each control, and the like in a memory. The main control circuit 31 includes detection signals from the outside air temperature sensor 16, the hot water temperature sensor 17, the incoming water temperature sensor 18 and the discharge temperature sensor 19, and the hot water temperature (set hot water temperature) Swo set by the hot water temperature setting device 36. The related signal is input.

  Based on the control signal from the main control circuit 31, the compressor drive circuit 32 sends a drive signal corresponding to the set target rotational speed RN (see steps ST4 and ST6 in FIG. 3) to the compressor operation motor 11a. . Based on the signal from the main control circuit 31, the expansion valve drive circuit 33 sends a drive signal corresponding to the set opening change amount P (see step SE4 in FIG. 7) to the expansion valve operating motor 13a. . The blower drive circuit 34 sends a predetermined drive signal to the blower operation motor 15 a based on the signal from the main control circuit 31. Based on the signal from the main control circuit 31, the pump drive circuit 35 sends a drive signal corresponding to the set rotation speed RP (see step SP3 in FIG. 10) to the pump operation motor 22a.

  Next, with reference to FIGS. 3-6, the 1st operation method implement | achieved with the hot water supply apparatus shown in FIG. 1 is demonstrated. This first operation method is an operation method based on compressor control.

  When the operation of the heat pump HP is started, the outside air temperature Ta and the incoming water temperature Twi are detected, and the environmental load Qk is calculated based on the detected outside air temperature Ta and the incoming water temperature Twi by the basic formula of Qk = α1 × Ta−α2 × Twi. Calculation is performed (see steps ST1 and ST2 in FIG. 3). Incidentally, α1 and α2 in the equation are coefficients.

  Then, using the data table shown in FIG. 4, a target rotational speed RN corresponding to the obtained value of the environmental load Qk is set (see steps ST3 and ST4 in FIG. 3). A11 to A16 in FIG. 4 indicate threshold values of the environmental load Qk, and have a relationship of A11 <A12 <A13 <A14 <A15 <A16. Further, RN1 to RN7 in FIG. 4 indicate values of the target rotational speed RN, and have a relationship of RN1> RN2> RN3> RN4> RN5> RN6> RN7.

  After the operation of the heat pump HP is started (during operation), the outside air temperature Ta and the incoming water temperature Twi are detected, and the environmental load Qk is calculated based on the detected outdoor air temperature Ta and the incoming water temperature Twi as Qk = α1 × Ta−α2 ×. Calculation is performed using the basic formula of Twi (see steps ST1 and ST2 in FIG. 3).

  Then, it is determined whether or not the obtained environmental load Qk is different from the previously obtained environmental load Qk at the start of operation. If the obtained environmental load Qk is different, the obtained environmental load Qk is the previously obtained environmental environment at the start of operation. It is determined whether the load is higher or lower than the load Qk (see steps ST3 and ST5 in FIG. 3). As a result of the determination, when there is no change in the environmental load Qk, the process proceeds to step ST1.

  On the other hand, when the obtained environmental load Qk is higher than the obtained environmental load Qk at the start of operation, the data table shown in FIG. 5 is used to respond to the obtained value of the environmental load Qk. A target rotational speed RN is set (see step ST6 in FIG. 3). A21 to A26 in FIG. 5 indicate threshold values of the environmental load Qk, which are in a relationship of A21 <A22 <A23 <A24 <A25 <A26, and each value of A21 to A26 is A11 to A11 shown in FIG. Each is larger than the value of A16. Further, RN1 to RN7 in FIG. 5 indicate values of the target rotational speed RN, and each value of RN1 to RN7 is the same as RN1 to RN7 shown in FIG.

  Further, when the obtained environmental load Qk is lower than the previously obtained environmental load Qk at the start of operation, the data table shown in FIG. 6 is used to respond to the obtained value of the environmental load Qk. A target rotational speed RN is set (see step ST6 in FIG. 3). A31 to A36 in FIG. 6 indicate threshold values of the environmental load Qk, and have a relationship of A31 <A32 <A33 <A34 <A35 <A36, and each value of A31 to A36 is A11 to A11 shown in FIG. Each is smaller than the value of A16. Further, RN1 to RN7 in FIG. 6 indicate values of the target rotational speed RN, and each value of RN1 to RN7 is the same as RN1 to RN7 shown in FIG.

  The above procedure is continuously performed until the operation of the heat pump HP is stopped. As can be seen from the above description, during operation of the heat pump HP, the lower the outside air temperature Ta or the higher the incoming water temperature Twi, the higher the target rotational speed RN is set. Thus, control is performed so that the target rotational speed RN is set.

  According to the first operation method, the environmental load Qk is calculated based on the external conditions depending on the outside air temperature Ta and the incoming water temperature Twi, and an appropriate target rotation of the compressor 11 is determined according to the obtained value of the environmental load Qk. The number RN is set. Specifically, the higher the target rotational speed RN is set in the compressor 11 as the outside air temperature Ta becomes lower or the incoming water temperature Twi becomes higher, the compressor 11 is based only on the outside air temperature. Compared with the case where the control is performed, it is possible to operate the heat pump HP in a more optimal state to improve the coefficient of performance (COP).

  Further, according to the first operation method, different data are obtained when the operation of the heat pump HP is started, when the environmental load Qk increases after the start of the operation, and when the environmental load Qk decreases after the start of the operation. Since the target rotational speed RN is set using the table, it is possible to further improve the coefficient of performance (COP) by setting a more appropriate target rotational speed RN according to the operating state.

  Next, a second operation method realized by the hot water supply apparatus shown in FIG. 1 will be described with reference to FIGS. This second operation method is an operation method based on expansion valve control.

  When the heat pump HP is operating, the outside air temperature Ta, the incoming water temperature Twi, and the discharge temperature Td are detected, and the set hot water temperature Swo is read (see steps SE1 and SE2 in FIG. 7). The set hot water temperature Swo is preset in units of 5 ° C. in the range of 65 ° C. to 90 ° C. as shown in FIG.

  Then, based on the detected outside air temperature Ta and incoming water temperature Twi, the target discharge temperature Tdt is calculated by an expression determined for each set hot water temperature Swo (see step SE3 in FIG. 7). The basic formula for calculating the target discharge temperature Tdt is Tdt = −β1 × Ta + β2 + β3 × (Twi−β4), but the values of the coefficients β1, β3 and the constant β2 are different for each set hot water temperature Swo. Specifically, the coefficient β3 becomes lower as the set hot water temperature Swo becomes higher, and the coefficient β1 and the constant β2 become higher as the set hot water temperature Swo becomes higher. The constant β4 is constant regardless of the set hot water temperature Swo. In FIG. 8, Tdt1 to Tdt6 indicate values of the target discharge temperature Tdt for each set hot water temperature Swo obtained by calculation, and when the values of Ta and Twi are the same, Tdt1 <Tdt2 <Tdt3 <Tdt4 <Tdt5 < Tdt6.

  Then, a temperature deviation ΔTd between the obtained target discharge temperature Tdt and the previously detected discharge temperature Td is calculated by the equation ΔTd = Tdt−Td, and the previously detected discharge temperature Td and 30 seconds before A change in temperature ΔTk with time with respect to the discharge temperature Td is calculated by the equation of Td ΔTk = Td−30 seconds before (see step SE4 in FIG. 7).

  Then, using the data table shown in FIG. 9, an opening change amount P corresponding to the obtained temperature deviation ΔTd and temperature change amount ΔTk is set (see step SE5 in FIG. 7). B1 to B6 in FIG. 9 indicate threshold values of the temperature deviation ΔTd, and have a relationship of B1> B2> B3> B4> B5> B6. Further, C1 to C4 in FIG. 9 indicate threshold values of the temperature change amount ΔTk, and have a relationship of C1> C2> C3> C4. Furthermore, −P1 to −P5, ± 0, + P1 to + P5 in FIG. 9 indicate values of the opening change amount P, and −P1 to −P5 are −P1> −P2> −P3> −P4> −. There is a relationship of P5, and + P1 to + P5 have a relationship of + P1 <+ P2 <+ P3 <+ P4 <+ P5.

  The above procedure is continuously performed until the operation of the heat pump HP is stopped. As can be seen from the above description, during the operation of the heat pump HP, the lower the outside air temperature Ta, the higher the incoming water temperature Twi, or the higher the set hot water temperature Swo, the higher the discharge temperature Td of the compressor 11. Thus, the opening degree change amount P of the expansion valve 13 is set, and the expansion valve 13 is controlled to have the opening degree change amount P set in this way.

  According to the second operation method, the target discharge temperature Tdt is calculated based on the external conditions depending on the outside air temperature Ta and the incoming water temperature Twi and the internal conditions depending on the set hot water temperature Swo, and the obtained target discharge temperature Tdt A temperature deviation ΔTd with respect to the discharge temperature Td and a temperature change amount ΔTk over time of the discharge temperature Td are calculated, and an appropriate opening degree change amount P is set according to the obtained values of the temperature deviation ΔTd and the temperature change amount ΔTk. Specifically, the opening degree change amount P of the expansion valve 13 is set such that the discharge temperature Td of the compressor 11 increases as the outside air temperature Ta decreases, the incoming water temperature Twi increases, or the set hot water temperature Swo increases. Therefore, the coefficient of performance (COP) can be improved by operating the heat pump HP in a more optimal state as compared with the case where the expansion valve 13 is controlled based only on the outside air temperature. Can.

  Next, with reference to FIGS. 10-11, the 3rd driving | running method implement | achieved with the hot water supply apparatus shown in FIG. 1 is demonstrated. This third operation method is an operation method based on pump control.

  When the heat pump HP is operating, the outside air temperature Ta and the incoming water temperature Twi are detected, and the set hot water temperature Swo is read (see steps SEP and SP2 in FIG. 10). As shown in FIG. 11, the set hot water temperature Swo is preset in units of 5 ° C. in the range of 65 ° C. to 90 ° C.

  Then, based on the detected outside air temperature Ta and the incoming water temperature Twi, the required hot water discharge capacity Q is calculated by an equation determined for each set hot water temperature Swo (see step SP3 in FIG. 10). The basic formula for calculating the required hot water capacity Q is Q = γ1 × Ta + γ2 + γ3 × (γ4-Twi), but the value of the constant γ2 is different for each set hot water temperature Swo. Specifically, the constant γ2 becomes lower as the set hot water temperature Swo becomes higher. The coefficients γ1, γ3 and the constant γ4 are constant regardless of the set hot water temperature Swo. Q1 to Q6 in FIG. 11 indicate values of necessary hot water discharge capacity Q for each set hot water temperature Swo obtained by calculation. When the values of Twi are the same, Q1> Q2> Q3> Q4> Q5> Q6 Become.

  Then, based on the required required hot water capacity Q, the previously detected incoming water temperature Twi and the preset hot water temperature Swo, the rotational speed RP is changed to RP = δ1 × [δ2 + {δ3 + δ4 × Q / (Swo−Twi)} / δ5]. Is calculated and set by the basic formula (see step SP4 in FIG. 10). Incidentally, δ1, δ4, δ5 in the equation are coefficients, and δ2, δ3 are constants.

  The above procedure is continuously performed until the operation of the heat pump HP is stopped. As can be seen from the above description, when the heat pump HP is operated, the higher the outside air temperature Ta, the higher the incoming water temperature Twi, or the lower the set hot water temperature Swo, the higher the rotational speed RP is set. Thus, the feed water pump 22 is controlled to have the rotation speed RP set in this way.

  According to the third operation method, the required hot water discharge capacity Q is calculated based on the external conditions depending on the outside air temperature Ta and the incoming water temperature Twi and the internal conditions depending on the set hot water temperature Swo, An appropriate rotation speed RP is set based on the set hot water temperature Swo and the incoming water temperature Twi. Specifically, the higher the outside air temperature Ta, the higher the incoming water temperature Twi, or the lower the preset hot water temperature Swo, the higher the value. Since the rotation speed RP is set in the feed water pump 22, the coefficient of performance (COP) is improved by operating the heat pump HP in a more optimal state as compared with the case where the feed water pump 22 is controlled based only on the outside air temperature. Can be achieved.

  In the above description, in order to promote understanding of the control contents, the first operation method (compressor control), the second operation method (expansion valve control), and the third operation method (pump control) are described. Although described separately, if the first operation method and the second operation method are used together, or if the first operation method and the third operation method are used together, then the second operation method and the third operation method are further performed. If the operation method is used in combination, the heat pump HP is further optimized by combining the first operation method, the second operation method, and the third operation method as compared with the case where each operation method is executed alone. It goes without saying that the coefficient of performance (COP) can be improved by operating in a stable state.

  In the above description, the circuit configuration using the variable capacity compressor 11 capable of controlling the rotational speed, the electronic expansion valve 13 capable of controlling the opening degree, and the water supply pump 22 capable of controlling the rotational speed is shown. However, when only the first operation method by the compressor control is executed, a general temperature type expansion valve is used instead of the electronic type expansion valve 13 and the rotation speed controllable water supply pump 22 is replaced. Even if a constant speed rotation water supply pump is used, the same effect as described above can be obtained. On the other hand, when only the second operation method based on the expansion valve control is executed, a constant speed rotating compressor is used instead of the compressor 11 capable of controlling the rotational speed, and the feed water pump 22 capable of controlling the rotational speed is used. Alternatively, the same effect as described above can be obtained by using a constant speed rotating water supply pump. On the other hand, when only the third operation method by the pump control is executed, a constant speed rotating compressor is used instead of the compressor 11 capable of controlling the rotation speed, and the electronic expansion valve 13 is generally used instead. Even if a typical temperature type expansion valve is used, the same effect as described above can be obtained.

It is a circuit block diagram of a hot-water supply apparatus. FIG. 2 is a control system diagram of the hot water supply device shown in FIG. 1. It is a flowchart which shows the 1st driving | running method implement | achieved with the hot water supply apparatus shown in FIG. It is a data table which concerns on a 1st driving | operation method. It is a data table which concerns on a 1st driving | running method. It is a data table which concerns on a 1st driving | running method. It is a flowchart which shows the 2nd operating method implement | achieved with the hot water supply apparatus shown in FIG. It is a data table which concerns on a 2nd driving | running method. It is a data table which concerns on a 2nd driving | running method. It is a flowchart which shows the 3rd operating method implement | achieved with the hot-water supply apparatus shown in FIG. It is a data table which concerns on a 3rd driving | running method.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Heat pump unit, HP ... Heat pump, 11 ... Compressor, 12 ... Heat exchanger, 12a ... Outlet, 12b ... Inlet, 13 ... Expansion valve, 14 ... Evaporator, 16 ... Outside temperature sensor, Ta ... Outside temperature 17 ... Hot water temperature sensor, Two ... Hot water temperature, 18 ... Incoming water temperature sensor, Twi ... Incoming water temperature, 19 ... Discharge temperature sensor, Td ... Discharge temperature, 20 ... Tank unit, 21 ... Hot water storage tank, 21 ... Feed water pump, 31 DESCRIPTION OF SYMBOLS ... Main control circuit, 32 ... Compressor drive circuit, 33 ... Expansion valve drive circuit, 35 ... Pump drive circuit, 36 ... Hot water temperature setting device, Qk ... Environmental load, RN ... Target speed of compressor, Swo ... Set hot water Temperature, Tdt: Target discharge temperature, ΔTd: Temperature deviation, ΔTk: Temperature change amount, Q: Necessary hot-water supply capacity, P: Change amount of expansion valve opening, RP: Number of rotations of water supply pump.

Claims (6)

A heat pump including at least a heat exchanger that exchanges heat between a compressor capable of controlling the rotation speed, a refrigerant, and water;
A hot water storage tank whose lower part is connected to the water inlet of the heat exchanger and whose upper part is connected to the outlet of the heat exchanger;
A water supply pump for feeding the water in the hot water storage tank to the heat exchanger;
An outside temperature sensor for detecting the outside temperature;
An incoming water temperature sensor for detecting the incoming water temperature to the heat exchanger;
At the time of heat pump operation, based on the detected outside air temperature and incoming water temperature, it is provided with a compressor control means for controlling so that the lower the outside air temperature, or the higher the incoming water temperature, the higher the rotational speed of the compressor.
A water heater characterized by that. The compressor control means includes means for calculating an environmental load based on the outside air temperature and the incoming water temperature, and setting a target rotational speed of the compressor according to the obtained value of the environmental load.
The hot water supply apparatus according to claim 1. A heat pump that exchanges heat between the compressor, the refrigerant, and water, and a heat pump that includes at least an expansion valve capable of opening control;
A hot water storage tank whose lower part is connected to the water inlet of the heat exchanger and whose upper part is connected to the outlet of the heat exchanger;
A water supply pump for feeding the water in the hot water storage tank to the heat exchanger;
An outside temperature sensor for detecting the outside temperature;
An incoming water temperature sensor for detecting the incoming water temperature to the heat exchanger;
A discharge temperature sensor for detecting the discharge temperature of the refrigerant from the compressor;
A tapping temperature setting device for setting the tapping temperature;
During the heat pump operation, based on the detected outside air temperature, incoming water temperature and discharge temperature, and set hot water temperature, the lower the outdoor air temperature, the higher incoming water temperature, or the higher set hot water temperature, the discharge temperature of the compressor. An expansion valve control means for controlling the opening of the expansion valve so as to be high,
A water heater characterized by that. The expansion valve control means calculates the target discharge temperature based on the outside air temperature, the incoming water temperature, and the set hot water temperature, and calculates the temperature deviation between the obtained target discharge temperature and the discharge temperature and the temperature change over time of the discharge temperature. And a means for setting the opening change amount of the expansion valve according to the obtained temperature deviation and the value of the temperature change amount,
The hot water supply apparatus according to claim 3. A heat pump including at least a heat exchanger that exchanges heat between the compressor, the refrigerant, and water;
A hot water storage tank whose lower part is connected to the water inlet of the heat exchanger and whose upper part is connected to the outlet of the heat exchanger;
A feed water pump capable of controlling the number of revolutions for feeding water in the hot water storage tank to the heat exchanger;
An outside temperature sensor for detecting the outside temperature;
An incoming water temperature sensor for detecting the incoming water temperature to the heat exchanger;
A tapping temperature setting device for setting the tapping temperature;
During the heat pump operation, based on the detected outside air temperature, incoming water temperature and set hot water temperature, the higher the outdoor air temperature, the higher incoming water temperature, or the lower the set hot water temperature, the higher the rotation speed of the water supply pump. A pump control means for controlling
A water heater characterized by that. The pump control means is a means for calculating the required hot water capacity based on the outside air temperature, the incoming water temperature and the set hot water temperature, and setting the number of rotations of the feed pump based on the required required hot water capacity, the set hot water temperature and the incoming water temperature. including,
The hot water supply device according to claim 5.

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