JP2005147610A - Heat pump water heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat pump water heater capable of performing the defrosting operation without changing the flow of a refrigerant circuit in the defrosting operation, shortening a defrosting time as it has high defrosting performance, and further saving the electricity expense by shortening a boiling-up time of a tank. <P>SOLUTION: In this heat pump water heater comprising a heat pump circuit constituted by connecting a compressor, a hot water supply heat exchanger, an expansion valve and an evaporator by pipes, and a fluid circuit constituted by connecting a hot water storage tank, a fluid circulation pump and a fluid circulation switching valve by pipes, further comprising a bypass circuit bypassing the hot water supply heat exchanger, and having the fluid circulation switching valve on the bypass circuit, a defrost start determining means for determining the start of defrosting and a fluid circulation switching valve driving means for driving the fluid circulation switching valve are mounted, and the fluid circulation switching valve is opened before or after determining the start of defrosting. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a heat pump hot water supply having a heat pump circuit in which a compressor, a hot water heat exchanger, an expansion valve, and an evaporator are connected by piping, a hot water tank, a fluid circulation pump, and a fluid circuit in which a fluid circulation switching valve is connected by piping. Relates to the device.

  Conventionally, in this type of defrosting method, a two-way valve or the like is arranged in a bypass circuit so that the refrigerant flows in the heat pump circuit from the compressor discharge side to the evaporator without passing through the hot water supply heat exchanger. In addition, it has been proposed to defrost the evaporator by controlling the two-way valve in the opening direction during the defrosting operation (see, for example, Patent Document 1). As another defrosting method, a proposal for stopping the fluid circulation pump during defrosting is conceivable.

It is possible to reliably defrost by providing a solenoid valve in the bypass circuit during defrosting and supplying hot gas to the inlet of the outdoor heat exchanger.
JP 2001-108256 A (Claim 1, Claim 2, Claim 3, and Claim 4)

  However, in the conventional configuration, the structure is complicated by adding a bypass circuit to the heat pump circuit, and the reliability of the solenoid valve against high-pressure refrigerant is ensured, resulting in an expensive solenoid valve. Moreover, since the flow of the refrigerant changes, there is a problem that refrigerant noise is generated.

  Further, if the fluid circulation pump is stopped during defrosting, the fluid may freeze at a low outside air temperature.

  The present invention solves the above-described problem. At the start of the defrosting operation, after opening the fluid circulation switching valve, the opening of the expansion valve is opened, and the heat exchanger for hot water supply is used. The present invention provides a heat pump hot water supply apparatus that performs defrosting with minimum heat dissipation.

  In order to solve the conventional problems, a heat pump circuit in which a compressor, a hot water heat exchanger, an expansion valve, and an evaporator are connected by piping, a hot water tank, a fluid circulation pump, and a fluid in which a fluid circulation switching valve is connected by piping. A heat pump water heater having a circuit, provided with a bypass circuit that bypasses the hot water heat exchanger, and provided with a fluid circulation switching valve in the bypass circuit, the fluid circulation switching valve at the start of the defrosting operation After opening, the opening of the expansion valve is opened.

  Further, in the heat pump water heater of the present invention, the determination of the defrosting operation start is performed by an evaporator temperature detecting means for detecting the temperature of the evaporator, and the evaporator temperature and the evaporator set temperature for determining the defrosting start. The difference in temperature between the evaporator defrost start determining means for determining the start of defrost from the temperature difference between the outside air temperature detecting means for detecting the outside air temperature, and the outside air set temperature for determining the defrost start. From the outside temperature defrosting start determining means for determining the start of defrosting, the compressor operating time storage means for storing the compressor operating time, the storage time of the compressor operating time and the set time for starting the defrosting operation. Each of the defrost start determinations determined from the evaporator defrost start determination means, the outside air temperature defrost start determination means, and the operation time defrost start determination means is provided. From the defrost start determination means , Wherein the defrosting operation is started.

  In the heat pump hot water supply apparatus of the present invention, the compressor capacity changing means for determining the start of the defrosting operation by the defrosting start determining means and changing the capacity of the compressor has the same capacity. Or it is characterized by increasing.

  The heat pump hot water supply apparatus of the present invention is characterized in that a connection port for connecting the fluid circulation switching valve in three directions is provided, and all the flow of fluid is switched by the operation of the fluid circulation switching valve.

  The heat pump hot water supply apparatus of the present invention is characterized in that the heat pump circuit is configured by a supercritical vapor pressure compression refrigeration cycle so that the refrigerant pressure on the high pressure side is equal to or higher than the critical pressure of the refrigerant.

  According to the present invention, during the defrosting operation, without changing the flow of the refrigerant during the heat pump hot water supply operation, the heat of defrosting can be used as the defrosting capacity without radiating heat to the heat exchanger for hot water supply as much as possible. The defrosting can be completed quickly by controlling the expansion valve.

  1st invention has the fluid circuit which connected the heat pump circuit which connected the compressor, the hot water heat exchanger, the expansion valve, and the evaporator with piping, the hot water storage tank, the fluid circulation pump, and the fluid circulation switching valve with piping. A heat pump hot water supply apparatus provided with a bypass circuit for bypassing the heat exchanger for hot water supply, and provided with the fluid circulation switching valve in the circuit, after opening the fluid circulation switching valve at the start of the defrosting operation Since the main flow of the fluid flow passes through the bypass circuit without passing through the hot water supply heat exchanger by opening the opening of the expansion valve, the refrigerant flow during the heat pump hot water supply operation is reduced in the defrosting operation. Without changing, the amount of heat of the compressor can be dissipated to the heat exchanger for hot water supply as much as possible, and it can be used for defrosting of the evaporator, and it is inexpensively configured without adding high pressure resistant functional parts of the refrigerant system it can.

  According to a second aspect of the present invention, the determination of the defrosting operation start is performed by a temperature difference between the evaporator temperature detecting means for detecting the temperature of the evaporator and the evaporator temperature and the evaporator set temperature for determining the defrosting start. Defrost start from the temperature difference between the evaporator defrost start determining means for determining the start of defrost from the outside air temperature detecting means for detecting the outside air temperature and the outside air temperature and the outside air set temperature for determining the defrost start Determining the start of defrosting based on the outside temperature defrosting start determining means for determining the compressor operating time storage means for storing the compressor operating time, the storage time of the compressor operating time and the set time for starting the defrosting operation Operating time defrosting start determining means to perform defrosting start from each defrosting start determination determined from the evaporator defrosting start determining means, the outside air temperature defrosting start determining means and the operating time defrosting start determining means Final determination is made by the determination means, and the defrosting operation is started. By recognizes the frost amount adhering to the evaporator, so that it is determined start defrosting operation.

  According to a third aspect of the present invention, the defrosting start determining means determines the start of the defrosting operation, and the compressor capacity changing means for changing the capacity of the compressor causes the compressor capacity to be the same or increased. Thus, when the capacity of the compressor is increased, the amount of heat necessary for defrosting can be increased by changing the capacity of the compressor, thereby improving the defrosting capacity. Moreover, when the capacity | capacitance of a compressor is equivalent and it enters into a defrost, the defrost operation which suppressed the noise generation at the time of a defrost operation can be performed.

According to a fourth aspect of the present invention, a connection port for connecting the fluid circulation switching valve in three directions is provided, and all the fluid flows are switched by the operation of the fluid circulation switching valve. Since all the heat quantity of the compressor can be used for defrosting, there is an effect that the defrosting time can be completed quickly and the tank boiling time can be shortened. Further, since water is passed through the connecting pipe connecting the tank unit and the heat pump unit, there is an effect of preventing the connecting pipe from freezing.

  According to a fifth aspect of the present invention, the heat pump circuit is constituted by a supercritical vapor pressure compression refrigeration cycle, and the refrigerant pressure on the high pressure side becomes a critical pressure abnormality of the refrigerant. As a refrigerant, a heat pump circuit can be configured.

(Embodiment 1)
Hereinafter, a heat pump water heater according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a circuit configuration diagram of a heat pump water heater according to an embodiment of the present invention.

  First, the heat pump circuit of the heat pump hot water supply apparatus according to this embodiment will be described.

  The heat pump circuit 10 according to the present embodiment preferably uses carbon dioxide as a refrigerant and is operated in a state where the critical pressure is exceeded on the high pressure side. In the present embodiment, carbon dioxide is used as the refrigerant, but there is no problem even if the heat pump circuit is constituted by other refrigerants.

  The heat pump circuit 10 is configured by connecting a compressor 11, a hot water supply heat exchanger 12, a main expansion valve 13A, a capillary tube 13B, and an evaporator 14 in this order by piping. The heat pump circuit 10 includes a temperature sensor (outside air temperature detection means) 10D that detects the intake air of the evaporator 14, and a temperature sensor (evaporator temperature detection means) 10E that detects the temperature near the outlet of the evaporator 14. .

  Next, a hot water storage circuit of the heat pump hot water supply apparatus according to this embodiment will be described.

  A hot water tank 20 is connected to a water supply pipe 32 such as a water pipe through a flow rate adjusting valve 31 from a bottom pipe. Further, the hot water storage tank 20 is connected to the inflow side of the water piping 12 </ b> A of the hot water supply heat exchanger 12 through the circulation pump 23. A bypass circuit 25 is provided in the heat pump unit so as to bypass the water flow of the hot water supply heat exchanger, and a fluid circulation switching valve 25A is connected to the bypass circuit. The upper circulation pipe 24 of the hot water storage tank 20 is connected to the outflow side of the water pipe 12A. The hot water storage tank 20 according to the present embodiment is a stacked hot water storage tank, and is configured so that stirring in the tank is prevented and high temperature water is accumulated at the top and low temperature water is accumulated at the bottom. By disposing the fluid circulation switching valve 25A at the above position, water can flow into the connection pipe 40 and freeze can be prevented.

  On the other hand, the upper hot water supply pipe 33 of the hot water storage tank 20 is connected to the mixing valve 34. The outlet circuit on the outflow side of the mixing valve 34 is connected to a faucet 36 for hot water supply such as a kitchen or a washroom.

  Since the hot water storage tank is not directly related to the present application, the description thereof is omitted.

  In FIG. 2, a bypass circuit 25 is provided in the tank unit so as to bypass the flow of water in the hot water heat exchanger, and a fluid circulation switching valve 25B is connected to the bypass circuit.

  Even at the position of the fluid circulation switching valve 25A, the effect of the defrosting performance is the same as that disposed on the heat pump unit side in FIG.

Further, FIG. 3 shows that a bypass circuit 25 is provided in the heat pump unit so as to bypass the flow of water in the hot water heat exchanger, and the bypass circuit 25 and a circuit flowing through the hot water heat exchanger are connected at the contact portion 3. The fluid circulation switching valve 25C having the other connection port is connected. By disposing the fluid circulation switching valve 25C at the above position, water does not flow at all in the hot water supply heat exchanger 12, so that no heat loss occurs in the hot water supply heat exchanger 12, and the connection pipe 40 has no water. Freezing can be prevented.

  Further, FIG. 4 shows that a bypass circuit 25 is provided in the tank unit so as to bypass the flow of water in the hot water heat exchanger, and the bypass circuit 25 and the circuit flowing through the hot water heat exchanger are connected to 3 points. The fluid circulation switching valve 25D having the other connection port is connected. By disposing the fluid circulation switching valve 25D at the above position, water does not flow at all in the hot water supply heat exchanger 12, and thus the heat loss in the hot water supply heat exchanger 12 can prevent heat loss.

  Hereinafter, the operation of the heat pump water heater according to the present embodiment will be described.

  The operation signal from the hot water storage tank is received and the operation of the heat pump unit is started.

  In the heat pump circuit 10, the refrigerant compressed by the compressor 11 dissipates heat in the hot water supply heat exchanger 12, is depressurized by the main expansion valve 13A and the capillary tube 13B, then absorbs heat in the evaporator 14, and in a gas state. It is sucked into the compressor 11.

  On the other hand, by the operation of the circulation pump 23, the water in the hot water storage tank 20 is led to the water pipe 12A through the bottom pipe, and the hot water heated by the water pipe 12A passes through the upper circulation pipe 24. Returned to the tank 20.

  Before and after the defrosting operation, the fluid circulation switching valve operates to be opened, and water flows into the bypass circuit 25 so that the water does not flow easily or does not flow through the hot water heat exchanger.

  The capacity control at the compressor 11 and the opening degree control at the expansion valve 13 are controlled such that the refrigerant discharge temperature maintains a preset temperature.

  Next, hot water storage operation start control of the heat pump hot water supply apparatus according to the present embodiment will be described with reference to FIGS.

  For a predetermined time from the start of the compressor 11, the operation is performed at the target frequency set at the start. After operating for a predetermined time at the target frequency, the operation mode is switched to the normal operation mode in which the refrigerant discharged from the compressor 11 maintains the predetermined temperature. In addition, from the start of operation of the compressor 11 until the target frequency is reached, start-up control is performed to increase the frequency stepwise.

  First, the process from the defrosting start determination to the functional component drive will be described with reference to FIG.

  FIG. 5 is a block diagram illustrating the defrosting operation from the defrosting start determination of the heat pump water heater according to the present embodiment.

The defrosting start determining means 48 is largely composed of three defrosting start determinations of an evaporator defrosting start determining means 45, an outside air temperature defrosting start determining means 46, and an operating time defrosting start determining means 47. The defrosting operation is started only when all the determinations are made. The evaporator defrosting start determining means 45 performs the defrosting determination from the evaporator temperature detecting means 10E for detecting the temperature of the evaporator and the evaporator temperature setting means 42 for determining the start of the defrosting of the evaporator. Start determination means 45 determines the start of defrosting based on the evaporator temperature. Next, the outside air temperature defrosting start judging means 46 has an outside air temperature detecting means 10D for detecting the outside air temperature and an outside air temperature setting means 43 for judging the start of defrosting of the outside air temperature.
The defrosting determination is performed, and the start of defrosting based on the outside air temperature is determined by the outside air temperature defrosting start determining means 46. Next, the operating time defrosting start determining means 47 performs the defrosting determination from the compressor operating time storage means 41 for storing the compressor operating time and the compressor operating time setting means 44 for determining the defrosting start from the compressor operating time. Then, the start of the defrosting operation is determined from the operation time of the compressor by the operation time defrosting start determining means 47.

  Next, the defrosting operation by the defrosting operation start determining means is started by the compressor capacity variable means 49, the expansion valve opening variable means 50, the fluid circulation pump flow rate variable means 51, and the fluid circulation switching means 52 based on the start signal. The valve, the flow circulation pump, and the fluid circulation switching valve are controlled.

  FIG. 6 is a flowchart illustrating a flow of driving the compressor, the expansion valve, the fluid circulation pump, and the fluid circulation switching valve from the defrosting start determination of the heat pump water heater according to the present embodiment.

  A compressor operation start signal is received from the tank unit, and the compressor operation starts. (S51) Next, the operation time is stored (S52). If the outside temperature is lower than the set outside temperature by comparing the outside temperature with the set outside temperature, the process proceeds to the next. (S53) Next, the evaporator temperature is compared with the set evaporator temperature, and if it is lower than the set evaporator temperature, the process proceeds to the next. (S54) Next, if the compressor operation time has elapsed, the defrosting start determination is determined. (S55, S56) The compressor, the expansion valve, the fluid circulation pump, and the fluid circulation switching valve are controlled based on the defrosting start determination. (S57, S58, S59, S60).

  FIG. 7 is a graph showing defrosting from the start of the defrosting operation of the heat pump water heater according to this embodiment.

  As shown in FIG. 7, the operation of the compressor, the expansion valve, the external fan, the fluid circulation pump, and the fluid circulation switching valve will be described from the start to the end of the defrosting.

  First, the fluid circulation switching valve is controlled in the opening direction simultaneously with the start of defrosting.

  After that, the opening of the expansion valve is increased stepwise in steps 2 and 3, and in step 3, the defrosting capacity is controlled to the maximum at the maximum opening. After the defrosting is completed, the opening is gradually reduced.

  At the start of the defrosting operation, the compressor is operated at a frequency equivalent to that at the previous normal operation, and then is operated at a high frequency from step 3 to increase the defrosting capability. This is because the change in sound does not increase.

  The outer fan is controlled so as not to be harmful to the defrosting operation by stopping from the start of the defrosting.

  The fluid circulation pump is controlled with a small flow rate (0.3 L / min) for 1 second and a minute flow rate (0.01 L / min) for 9 seconds so as not to dissipate heat for defrosting with a heat exchanger for hot water supply. The fluid circulation pump is controlled.

  In addition, the start determination of a defrost operation may not be determined from all parameters of the evaporator temperature, the outside air temperature, and the compressor operation time, but may be determined from one or two of them.

  As described above, the present invention relates to a defrosting method in a heat pump hot water supply apparatus, and the heat pump hot water supply apparatus of the present invention has, for example, a bath water supply function, a heating function, and a drying function in addition to the hot water supply function. Also suitable for.

The circuit block diagram which arranged the fluid circulation switching valve in the heat pump unit side of the heat pump hot-water supply apparatus by one Example of this invention The circuit block diagram which has arrange | positioned the fluid circulation switching valve in the tank unit side of the heat pump hot-water supply apparatus by one Example of this invention The circuit block diagram which has arrange | positioned the fluid circulation switching 3 way valve in the heat pump unit side of the heat pump hot-water supply apparatus by one Example of this invention. The circuit block diagram which has arrange | positioned the fluid circulation switching 3 way valve in the tank unit side of the heat pump hot-water supply apparatus by one Example of this invention Block diagram of a heat pump water heater according to this embodiment Control flow chart of heat pump water heater according to this embodiment The graph which shows the control action of the heat pump hot-water supply apparatus by a present Example

Explanation of symbols

10 heat pump circuit 10D temperature sensor (outside air temperature detection means)
DESCRIPTION OF SYMBOLS 11 Compressor 12 Hot water supply heat exchanger 13A Main expansion valve 14 Evaporator 20 Hot water storage tank 23 Fluid circulation pump 24 Upper circulation piping 25A Fluid circulation switching valve 40 Connection piping

Claims (5)

A heat pump circuit in which a compressor, a heat exchanger for hot water supply, an expansion valve, and an evaporator are connected by piping and a hot water tank, a fluid circulation pump, and a fluid circuit in which a fluid circulation switching valve is connected by piping; A heat pump hot water supply apparatus provided with a bypass circuit for bypassing a heater, and provided with a fluid circulation switching valve in the bypass circuit, wherein the expansion valve is operated after opening the fluid circulation switching valve at the start of a defrosting operation. The heat pump hot water supply apparatus characterized by opening the opening degree of. The determination of the start of the defrosting operation is performed by determining the start of defrosting from the temperature difference between the evaporator temperature detecting means for detecting the temperature of the evaporator and the evaporator temperature and the evaporator set temperature for performing the defrosting start determination. The outside defrost start determining means, the outside temperature detecting means for detecting the outside air temperature, and the outside air temperature removal for determining the start of the defrost based on the temperature difference between the outside air temperature and the outside air set temperature for performing the defrost start determination. Defrost start determination means, compressor operation time storage means for storing the compressor operation time, operation time for determining the defrost start from the storage time of the compressor operation time and the set time for defrost operation start Defrost start A determination means, and a final determination is made by the defrost start determination means from each defrost start determination determined from the evaporator defrost start determination means, the outside air temperature defrost start determination means and the operating time defrost start determination means. And starting defrosting operation The heat pump water heater according to Motomeko 1. The start of the defrosting operation is determined by the defrosting start determining means, and the compressor capacity is varied by the compressor capacity varying means for varying the capacity of the compressor. The heat pump hot-water supply apparatus of 1 or 2. The heat pump hot water supply device according to claim 1, wherein a connection port for connecting the fluid circulation switching valve in three directions is provided, and all the flow of fluid is switched by the operation of the fluid circulation switching valve. The heat pump circuit comprises a supercritical vapor pressure compression refrigeration cycle, and the refrigerant pressure on the high pressure side is equal to or higher than the critical pressure of the refrigerant. Item 5. The heat pump hot water supply apparatus according to Item 4.

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