JP2005201538A - Heat pump type water heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat pump type water heater capable of raising the temperature of hot water to be supplied to a thermal load, rapidly to a target temperature. <P>SOLUTION: This heat pump type water heater regulates the temperature of hot water to be supplied to a panel heater 12 (the thermal load) by changing the speed (rotating speed) of a compressor 4 by a controller 19. The temperature of hot water to be supplied to the panel heater 12 is detected by a temperature sensor 18. When the difference between the detected temperature of the temperature sensor 18 and a standard temperature (the target temperature -2°C) is -8 or less at the start of operation, a controller 19 sets the speed of the compressor to "8" which is the maximum and maintains the speed until the difference becomes "2" which is the target temperature. When the detected value falls, the speed of the compressor 4 is raised according to the fall width. When the detected value rises, the speed of the compressor 4 is maintained without reducing it until reaching the target temperature. When the detected value rises to the upper limit value and then falls, the compressor 4 is not operated until the operation start temperature lower than the target temperature, and upon reaching the operation start temperature, the compressor 4 is operated at the maximum speed. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a heat pump water heater that changes the capacity of a compressor and supplies hot water having a predetermined temperature to a heat load.

  2. Description of the Related Art Heat pump water heaters that can change the capacity of a compressor in stages have been widely used in air conditioners and water heaters. As an example used in an air conditioner, one disclosed in Patent Document 1 below is known. In such a conventional heat pump type water heater, as shown in FIG. 3, the capacity (number of rotations) of the compressor is changed stepwise according to the temperature difference between the room temperature and the target temperature. For example, during the heating operation, when the difference between the room temperature and the target temperature is large, control is performed to increase the capacity of the compressor. When the temperature difference between the room temperature and the target temperature is small, the compressor is accordingly increased. Is controlled so as to lower the ability.

  However, when the temperature difference between the room temperature and the target temperature becomes small, that is, when the room temperature approaches the target temperature, the capacity of the compressor also decreases, so the degree of increase in the room temperature decreases, and the room temperature decreases. It took time to reach the target temperature.

In addition, in the technique disclosed in Patent Document 1 below, an auxiliary heater is used in combination with the heat pump water heater, but the temperature difference between the room temperature and the target temperature is reduced, and the capacity of the compressor is reduced. Even in the state, the auxiliary heater is operated. In general, since the auxiliary heater is inferior in energy efficiency to the heat pump, the capacity of the heat pump having high energy efficiency cannot be utilized to the maximum.
Japanese Patent Laid-Open No. 5-256696 (Description 0026 to 0027, FIG. 4)

  An object of the present invention is to improve a heat pump water heater, and more specifically, in order to eliminate the inconvenience, a heat pump water heater capable of quickly raising the temperature of hot water supplied to a heat load to a target temperature is provided. The purpose is to provide. Moreover, when using an auxiliary heater together, it aims at utilizing the capability of a heat pump with high energy efficiency to the maximum.

  In order to achieve the above object, a heat pump water heater of the present invention includes a refrigerant circuit in which a compressor, a condenser, an expansion valve, and an evaporator are connected in order, and the refrigerant circuit by the condenser. A heat pump type water heater comprising a hot water circuit having a circulation pump, a supply port for supplying hot water to the heat load, and a circulation port for returning the hot water from the heat load, A temperature sensor for detecting the temperature of the supplied hot water and a controller for controlling the capacity of the compressor based on a detection value of the temperature sensor are provided, and the following control is performed.

  The controller has a target temperature of hot water supplied to the heat load, and controls the capacity of the compressor to a predetermined reference capacity when the detected value of the temperature sensor is the target temperature. When the detected value of the temperature sensor falls below the target temperature, increase the capacity of the compressor according to the difference between the detected value and the target temperature, and operate with the increased capacity of the compressor, When the detection value of the temperature sensor rises, the set compressor capacity is maintained until the detection value reaches the target temperature.

  The heat pump water heater of the present invention increases the capacity of the compressor when the detected value of the temperature sensor falls below the target temperature, and increases the detected value until the detected value reaches the target temperature. maintain. Therefore, the temperature of the hot water supplied to the heat load can be quickly increased to a desired temperature as compared with the conventional apparatus.

  In the heat pump water heater of the present invention, not only the compressor capacity is maintained until the detected value reaches the target temperature at the start of operation, but also the amount of heat consumed in the heat load increases rapidly during operation. Even when the detection value of the temperature sensor suddenly decreases, the capacity of the compressor is maintained until the detection value reaches the target temperature. For this reason, the temperature of the hot water supplied to the heat load can be quickly raised to a desired temperature not only at the start of operation but also during operation.

  Further, the controller controls the capacity of the compressor to a reference capacity when the detected value of the temperature sensor reaches the target temperature. Since the controller controls the temperature of the hot water supplied to the heat load to be the target temperature, there is a frequency that the capacity of the compressor becomes the reference capacity during the operation of the heat pump water heater of the present invention. high. Accordingly, when determining the reference capacity, an appropriate value can be obtained by taking into consideration the capacity and durability of the compressor and setting it to an appropriate value.

  In the heat pump water heater of the present invention, the controller has an operation start temperature set lower than the target temperature according to the characteristics of the thermal load, and a detection value of the temperature sensor is the target temperature. When the detected value and the target temperature are increased, the capacity of the compressor is decreased according to the difference between the detected value and the target temperature, and when the detected value reaches a predetermined upper limit temperature by setting the compressor to the minimum capacity. The operation of the compressor is stopped, and when the detected value of the temperature sensor decreases while the operation of the compressor is stopped, the stopped state is maintained until the operation start temperature is reached, and the detected value is When the start temperature is reached, it is preferable to start the operation by maximizing the capacity of the compressor and to operate the compressor at the maximum capacity until the detected value reaches the target temperature.

  When the detected value of the temperature sensor exceeds the target temperature and the detected value reaches the upper limit temperature even when the capacity of the compressor is minimized, the amount of heat consumed by the heat load is small. Therefore, even if the detected value of the temperature sensor falls to the target temperature after the operation of the compressor is stopped, the detected value immediately reaches the upper limit temperature when the operation of the compressor is resumed at this time. Therefore, there is a possibility that the operation of the compressor must be stopped again. Therefore, in the present invention, after the operation of the compressor is stopped, an operation start temperature lower than the target temperature is set, and the operation of the compressor is stopped up to the operation start temperature. Further, when the detected value of the temperature sensor falls to the operation start temperature, the capacity of the compressor is maximized until the detected value reaches the target temperature so that the detected value quickly reaches the target temperature. I have to. In this way, the compressor can be operated only when necessary, and when operating, the energy efficient operation of the entire apparatus can be performed by using a high rotation region with high energy efficiency.

  The operation start temperature is determined according to the characteristics of the heat load. For example, if the thermal load is such that the temperature change does not affect the room temperature sensitively, such as a panel heater of an air conditioner, the operation start temperature is not satisfactory even if the operation start temperature is much lower than the target temperature. Therefore, a large difference from the target temperature may be provided in consideration of energy efficiency. On the other hand, if the heat load has a sensitive effect on the user, such as a fan convector of an air conditioner or a hot water tank used for hot water supply, it will affect the user. It is preferable to determine the value so as to reduce the value.

  In the heat pump water heater of the present invention, when the auxiliary heater for heating the hot water is provided in the hot water circuit, the controller is set to be lower than the target temperature according to the characteristics of the heat load. A target temperature and an auxiliary heater operating temperature set lower than the operation start temperature, and when the detected value of the temperature sensor is equal to or lower than the auxiliary heater operating temperature, the auxiliary heater is operated, and the detected value is It is preferable that the operation of the auxiliary heater is maintained until the second target temperature is reached, and the operation of the auxiliary heater is stopped when the detected value reaches the second target temperature.

  Since the auxiliary heater is not energy efficient as compared with heating of hot water by the refrigerant circuit, in the present invention, the operation start temperature of the auxiliary heater is set lower than the operation start temperature of the compressor, and the compressor With only heating by the above, the auxiliary heater is operated only when the detection value of the temperature sensor falls below the operation start temperature. Accordingly, since the auxiliary heater does not operate in a state where the capacity of the compressor is low, the capacity of the compressor can be utilized to the maximum and the auxiliary heater can be operated only when necessary.

  Further, when determining the second target temperature, the characteristics of the heat load are taken into consideration, and when the temperature change of the heat load does not directly affect the user, the user feels uncomfortable considering the energy efficiency. It is preferable to increase the difference between the second target temperature and the target temperature within a range not given. Further, when the user is sensitively affected by the temperature change of the thermal load, it is preferable to reduce the difference between the second target temperature and the target temperature.

  Next, an example of an embodiment of the heat pump water heater of the present invention will be described with reference to FIG. 1 and FIG. As shown in FIG. 1, the heat pump water heater 1 of this embodiment is used in a heating system including a refrigerant circuit 2 and a hot water circuit 3.

  The refrigerant circuit 2 includes a compressor 4 that compresses the refrigerant, a condenser 5 provided in order on the downstream side, an electronic expansion valve 6, and an evaporator 7. In this embodiment, the evaporator 7 is provided in the ventilation unit 8 that discharges indoor air to the outside, and is configured to recover the heat of the air discharged from the room. A known dryer 9 and sight glass 10 are provided between the condenser 5 and the electronic expansion valve 6.

  The hot water circuit 3 includes a circulation pump 11 that circulates hot water, a supply port 13 that supplies hot water to a panel heater 12 (heat load) provided on the downstream side, and a reflux port through which hot water returned from the panel heater 12 flows. 14, an expansion tank 15 provided on the downstream side thereof, an auxiliary heater 16 provided on the downstream side of the condenser 5, and a hot water storage tank 17 provided on the downstream side thereof. A temperature sensor 18 that detects the temperature of the hot water supplied from the supply port 13 is provided on the downstream side of the circulation pump 11.

  Moreover, the heat pump water heater 1 of this embodiment includes a controller 19 that performs operation control of the compressor 4 and the like. The controller 19 compares the detected value of the temperature sensor 18 with the target temperature or the second target temperature of the hot water supplied to the panel heater 12, and the EEPROM 21 that stores the target temperature, the second target temperature, and the like. And. The controller 19 is electrically connected to the compressor 4 and the electronic expansion valve 6 of the refrigerant circuit 2. The controller 19 is electrically connected to the circulation pump 11, the auxiliary heater 16, and the temperature sensor 18 of the hot water circuit 3.

  In the present embodiment, the controller 19 performs the control of the capacity of the compressor 4 by changing the speed (number of rotations) stepwise. Specifically, in the control diagram of FIG. 2, the vertical axis represents the speed of the compressor 4, and the speed is 9 levels from “8” of maximum capacity to “1” of minimum capacity and “0” of stop. It is divided into. 2 indicates the difference between the detected value of the temperature sensor 18 and the standard temperature stored in the EEPROM 21.

  In this embodiment, the standard temperature + 2 ° C. is set as the target temperature, and the standard temperature is set as the second target temperature. This standard temperature is a standard value of the heat load connected to the heat pump water heater 1. In this embodiment, a value obtained by adding 2 ° C. as the correction value for the panel heater 12 is set as the target temperature.

  Further, in the present embodiment, the controller 19 is programmed to control the speed of the compressor 4 to “3” which is the reference capacity when the detected value of the temperature sensor 18 is the target temperature. This reference capacity is determined by considering the heat consumption of the heat load, the capacity of the compressor 4 and the like, and selecting a speed with a good balance between the energy efficiency and the durability of the compressor 4 in the apparatus. In this case, the speed of the compressor 4 is “3”.

  In this embodiment, the operation start temperature of the auxiliary heater 16 is set to a temperature that is 10 ° C. lower than the standard temperature (a temperature that is 12 ° C. lower than the target temperature). This temperature difference can be changed arbitrarily depending on the nature of the heat load. In the present embodiment, since the thermal load is the panel heater 12, the temperature change does not sensitively affect the indoor temperature change, and thus this temperature difference is used.

  Next, the operation of the heat pump water heater 1 of the present embodiment will be described with reference to FIG. In FIG. 2, the state where the detection value of the temperature sensor 18 is rising is indicated by a solid line, and the state where the detection value is falling is indicated by a dotted line.

  First, the case where the operation is started in a state where the detected value of the temperature sensor 18 is 10 ° C. or more lower than the standard temperature will be described. When the operation of the heating system using the heat pump water heater 1 of the present embodiment is started, the controller 19 operates the circulation pump 11 and is supplied from the supply port 13 to the panel heater 12 by the temperature sensor 18. Detect the temperature of hot water. Then, the comparison means 20 compares the detected value of the temperature sensor 18 with the standard temperature stored in the EEPROM 21.

  Since the detected value of the temperature sensor 18 is low at the start of operation and is 10 ° C. or more lower than the standard temperature, the comparison result by the comparison means 20 is less than “−10”. Therefore, the controller 19 operates with the speed of the compressor 4 as the maximum “8”. Further, since the result of the comparison means 20 is lower than the standard temperature of −10 ° C. that is the operation start temperature of the auxiliary heater 16, the controller 19 operates the auxiliary heater 16.

  As described above, when the speed of the compressor 4 is maximized and the warm water is heated by the auxiliary heater 16, the detection value of the temperature sensor 18 increases, so that the comparison result by the comparison means 20 gradually decreases from less than "-10". It approaches “0”. At this time, for example, even when the comparison result by the comparison means 20 is point A between “−6” and “−4”, the controller 19 does not decrease the speed of the compressor 4 and reduces the maximum “ 8 ”.

  When the detected value of the temperature sensor 18 reaches the standard temperature, that is, the second target temperature, the comparison result by the comparison means 20 becomes “0”, so the controller 19 stops the operation of the auxiliary heater 16. As described above, the operation of the auxiliary heater 16 is stopped at the second target temperature instead of the target temperature if the temperature of the hot water supplied to the panel heater 12 can be rapidly raised to the second target temperature. This is because it may take some time to correct the temperature for achieving the target temperature, and the energy consumption is less when the refrigerant circuit 2 that is more energy efficient than the auxiliary heater 16 is used for the correction.

  On the other hand, the controller 19 maintains the maximum speed of the compressor 4 at “8”. In this state, when the amount of heat of hot water sent from the supply port 13 exceeds the amount of heat radiated from the panel heater 12, the detection value of the temperature sensor 18 further rises to the target temperature and is compared by the comparison means 20. The result is “2”. At this time, the controller 19 changes the speed of the compressor 4 to “3” which is the reference capacity. When the speed of the compressor 4 is “3” and the comparison result by the comparison unit 20 is “0” or more and less than “4”, the controller 19 holds the speed of the compressor 4 at “3”. Continue driving in the state. In the heat pump water heater 1 of the present embodiment, the state in which the detected value of the temperature sensor 18 is in the vicinity of the corrected target temperature in consideration of the capacity of the compressor 4 and the heat capacity of the panel heater 12 is higher than in other states. It is programmed to be.

  When the detected value of the temperature sensor 18 decreases when the heat radiation amount of the panel heater 12 is large and the speed of the compressor 4 is “3”, the controller 19 compresses if the comparison result of the comparison means 20 becomes “0”. The speed of the machine 4 is “4”, which is one level higher. Even when the speed of the compressor 4 is set to “4”, when the detection value of the temperature sensor 18 decreases and the comparison result of the comparison means 20 becomes “−2”, the controller 19 Increase the speed of 4 to "5". As described above, when the heat radiation amount of the panel heater 12 is large and the detection value of the temperature sensor 18 gradually decreases from the target temperature, the controller 19 increases the speed of the compressor 4 by one step every time the temperature decreases by 2 ° C. Is controlling.

  On the other hand, even when the detected value of the temperature sensor 18 increases while the speed of the compressor 4 is set to “5” and the comparison result of the comparison means 20 becomes “−2”, the controller 19 performs the compression. The operation of the compressor 4 is continued in the state of “5” without changing the speed of the machine 4 to “4”. That is, the controller 19 operates the compressor 4 while maintaining the speed of the compressor 4 at “5” when the comparison result of the comparison means 20 is “−2” or more and less than “2”. Thus, in the present embodiment, when the amount of heat generated by the refrigerant circuit 2 exceeds the amount of heat released from the panel heater 12 and the detected value of the temperature sensor 18 increases, the controller 19 increases the speed of the compressor 4 according to the temperature increase. Instead of reducing the number, the speed of the compressor 4 is maintained until the detected value of the temperature sensor 18 reaches the target temperature. By performing such control, the detection value of the temperature sensor 18 can be quickly raised to the target temperature.

  Next, the control when the heat radiation amount from the panel heater 12 is reduced during the operation of the heat pump water heater 1 of the present embodiment with the standard capacity will be described. When the detected value of the temperature sensor 18 is the target temperature, the speed of the compressor 4 is “3”, which is the reference capacity. When the amount of heat released from the panel heater 12 decreases in such a state, the detection value of the temperature sensor 18 gradually increases. When the detected value of the temperature sensor 18 rises by 4 ° C. from the standard temperature and the result of the comparison means 20 becomes “4”, the controller 19 reduces the speed of the compressor 4 to “2” and compares When the result of the means 20 becomes “6”, the controller 19 reduces the speed of the compressor 4 to “1”. When the detected value of the temperature sensor 18 further increases and the result of the comparison means 20 becomes “12”, the controller 19 stops the operation of the compressor 4. The controller 19 operates the circulation pump 11 of the hot water circuit 3.

  In this state, even if the detected value of the temperature sensor 18 decreases and falls below the standard temperature, the controller 19 does not resume the operation of the compressor 4 and the detected value of the temperature sensor 18 is 8 below the standard temperature. When the temperature has dropped, the speed of the compressor 4 is set to the maximum “8” and the operation is resumed. The controller 19 maintains the speed of the compressor 4 at “8” until the detected value of the temperature sensor 18 reaches the target temperature. When the detected value of the temperature sensor 18 reaches the target temperature, the controller 19 The speed is switched to the standard ability “3”.

  At this time, the result of the comparison means 20 is “−8”, which is higher than “−10” which is the operation start temperature of the auxiliary heater 16, so the controller 19 does not operate the auxiliary heater 16. This is because the temperature of the hot water can be sufficiently increased only by operating the refrigerant circuit 2 without operating the auxiliary heater 16 in a state where the heat radiation amount of the panel heater 12 is small.

  Next, control when the heat radiation amount from the panel heater 12 exceeds the capacity of the refrigerant circuit 2 while the heat pump water heater 1 of the present embodiment is operated with the standard capacity will be described. When the heat radiation amount of the panel heater 12 is increased while operating the speed of the compressor 4 at “3” which is the reference capacity, the detection value of the temperature sensor 18 gradually decreases. At this time, the controller 19 increases the speed of the compressor 4 by “1” every time the detected value of the temperature sensor 18 falls by 2 ° C. from the target temperature. When the amount of heat released from the panel heater 12 exceeds the capacity of the refrigerant circuit 2, the detected value of the temperature sensor 18 falls by 8 ° C. or more from the standard temperature, and the speed of the compressor 4 is “8” which is the maximum. Even in the state, the detection value of the temperature sensor 18 further decreases. When the detected value of the temperature sensor 18 falls by 10 ° C. or more from the standard temperature and reaches the operation start temperature of the auxiliary heater 16, the controller 19 operates the auxiliary heater 16 to heat the hot water in the hot water circuit 3.

  As described above, in the present embodiment, the auxiliary heater 16 is not used when the heat radiation amount of the panel heater 12 can be covered only by the refrigerant circuit 2, and only when the heat radiation amount of the panel heater 12 cannot be covered only by the refrigerant circuit 2. An auxiliary heater 16 is used. Since the refrigerant circuit 2 has better energy efficiency than the auxiliary heater 16, the energy efficiency of the entire apparatus can be improved by performing the control as in the present embodiment.

  In addition, although the example using the panel heater 12 as a heat load was demonstrated in the said embodiment, the heat pump type water heater of this invention is not limited to this, the fan convector used for a warm air heater, and hot water supply Therefore, it can be applied to various heat loads such as a hot water tank. At this time, a correction value (including a negative value) added to the standard temperature when the target temperature is determined and the speed of the compressor 4 that is the reference capacity may be determined according to the nature of the heat load.

  Moreover, in the said embodiment, although the controller 19 changes the rotation speed of the compressor 4 in steps according to the increase / decrease in the detected value of the temperature sensor 18, you may change smoothly not stepwise.

The schematic diagram which shows the structure of the heat pump type water heater of this embodiment. The operation figure which shows the action | operation of the heat pump type water heater of this embodiment. The operation figure which shows the action | operation of the conventional heat pump type | formula air conditioner.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Heat pump type water heater, 2 ... Refrigerant circuit, 3 ... Hot water circuit, 4 ... Compressor, 5 ... Condenser, 6 ... Electronic expansion valve, 7 ... Evaporator, 11 ... Circulation pump, 12 ... Panel heater (heat load) ), 13 ... supply port, 14 ... reflux port, 18 ... temperature sensor, 19 ... controller.

Claims (3)

A refrigerant circuit in which a compressor, a condenser, an expansion valve, and an evaporator are sequentially connected;
Heat pump hot water comprising a hot water circuit that performs heat exchange with the refrigerant circuit by the condenser and has a circulation pump, a supply port for supplying hot water to the heat load, and a reflux port for returning the hot water from the heat load. A vessel,
A temperature sensor that detects the temperature of hot water supplied to the thermal load; and a controller that controls the capacity of the compressor based on a detection value of the temperature sensor;
The controller has a target temperature of hot water supplied to the heat load;
When the detection value of the temperature sensor is the target temperature, control the capacity of the compressor to a predetermined reference capacity,
When the detected value of the temperature sensor falls below the target temperature, increase the capacity of the compressor according to the difference between the detected value and the target temperature, and operate with the increased capacity of the compressor, When the detection value of the temperature sensor rises, the heat pump type water heater is characterized in that the compressor capacity set until the detection value reaches the target temperature is maintained. The controller has an operation start temperature set lower than the target temperature according to the characteristics of the heat load,
When the detection value of the temperature sensor rises above the target temperature, the capacity of the compressor is lowered according to the difference between the detection value and the target temperature, and the detection value is set to the minimum capacity. When the temperature reaches a predetermined upper limit temperature, the operation of the compressor is stopped, and when the detected value of the temperature sensor decreases while the operation of the compressor is stopped, the operation is stopped until the operation start temperature is reached. When the detected value reaches the operation start temperature, the compressor is started at the maximum capacity until the detected value reaches the target temperature, and the compressor is operated at the maximum capacity. The heat pump type water heater according to claim 1. An auxiliary heater for heating hot water is provided in the hot water circuit,
The controller has a second target temperature set lower than the target temperature and an auxiliary heater operating temperature set lower than the operation start temperature according to the characteristics of the heat load,
When the detected value of the temperature sensor is equal to or lower than the auxiliary heater operating temperature, the auxiliary heater is operated, the operation of the auxiliary heater is maintained until the detected value reaches the second target temperature, and the detected value is the first value. 2. The heat pump water heater according to claim 2, wherein when the target temperature is reached, the operation of the auxiliary heater is stopped.

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