JP2005098546A - Heat pump type water heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat pump type water heater capable of securing reliability on a compressor, shortening the rising time, and finishing sufficient boil within the predetermined time. <P>SOLUTION: The heat pump type water heater has a heat pump circuit 10 formed by connecting the compressor 11, a water heating heat exchanger 12 and an evaporator 14, and has a hot-water storage circuit for supplying the water in a lower part of a hot-water storage tank 20 to the heat exchanger 12 and for filling hot-water heated by the heat exchanger 12 into an upper part of the hot-water storage tank 20. The compressor 11 has a variable operation frequency. The heat pump type water heater is provided with an open air temperature detecting means 10D, a filling water temperature detecting means 20D for detecting temperature of water to be supplied to the heat exchanger 12, a supplying hot-water temperature detecting means 20E for detecting temperature of the hot-water to be led from the heat exchanger 12 to the hot-water storage tank 20, and a frequency deciding means for deciding operation frequency of the compressor 11. The frequency deciding means decides a target frequency when starting the compressor 11 on the basis of the open air temperature, the filling water temperature and the supplying hot-water temperature. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a heat pump hot water supply apparatus having a heat pump circuit in which a compressor, a hot water supply heat exchanger, an expansion valve, and an evaporator are connected by piping, and the operating frequency of the compressor is variable.

Conventionally, a heat pump hot water supply apparatus using a variable capacity compressor has been proposed.
In order to make full use of the hot water storage capacity of the hot water storage tank, the capacity of the compressor is made variable according to the incoming water temperature led to the heat exchanger for hot water supply, and the capacity of the compressor is also changed by the outside air temperature. It has been proposed to boil all hot water in a hot water storage tank (for example, Patent Document 1).
In Patent Document 1, when the incoming water temperature is high, it is possible to prevent the compressor from stopping early by reducing the capacity of the compressor, and when the outside air temperature is low, the capacity of the compressor is increased. Can be surely heated.
JP 2002-48420 A (Claim 1, Claim 2)

The heat pump hot water supply apparatus has a problem that it takes time to start up as compared with a hot water supply apparatus using the combustion heat of gas and a hot water supply apparatus using an electric heater.
In order to make the heat pump hot water supply rise quickly, it can be considered that the operation frequency of the compressor is set to the highest frequency, but the reliability of the compressor is lowered.
Therefore, it is necessary to determine the operating frequency of the compressor so as not to be overloaded.
As described above, in Patent Document 1, although the capacity of the compressor is determined by the incoming water temperature and the outside air temperature, it is control for reliably boiling hot water in the hot water storage tank, and control at the time of starting the compressor. is not.

  An object of this invention is to provide the heat pump hot-water supply apparatus which can complete boiling within the predetermined time by ensuring the reliability of a compressor and making start-up time early.

The heat pump hot water supply apparatus of the present invention according to claim 1 has a heat pump circuit in which a compressor, a hot water heat exchanger, an expansion valve, and an evaporator are connected by piping, and the operating frequency of the compressor is variable. A hot water supply apparatus, wherein an outside air temperature detecting means for detecting an outside air temperature, an incoming water temperature detecting means for detecting an incoming water temperature supplied to the hot water supply heat exchanger, and heat exchange by the hot water supply heat exchanger Target hot water temperature setting means for setting the hot water temperature and frequency determining means for determining the operating frequency of the compressor, wherein the frequency determining means determines the target frequency at the start of the compressor as the target hot water temperature. It is determined using the target hot water temperature set by the setting means, the outside air temperature detected by the outside air temperature detecting means, and the incoming water temperature detected by the incoming water temperature detecting means.
According to a second aspect of the present invention, in the heat pump hot water supply device according to the first aspect, in the frequency determining means, when the outside air temperature is not lower than a first set temperature and not higher than a second set temperature, the input temperature A target frequency at the start of the compressor is determined according to a water temperature.
According to a third aspect of the present invention, in the heat pump hot water supply apparatus according to the second aspect, the frequency determining means increases the target frequency when the outside air temperature is equal to or lower than a first set temperature. And
According to a fourth aspect of the present invention, in the heat pump hot water supply apparatus according to the third aspect, the target frequency is increased according to the outside air temperature.
According to a fifth aspect of the present invention, in the heat pump hot water supply apparatus according to the second aspect, the frequency determining means reduces the target frequency when the outside air temperature is equal to or higher than a second set temperature. And
According to a sixth aspect of the present invention, in the heat pump hot water supply apparatus according to the fifth aspect, the target frequency is reduced according to the outside air temperature.
According to a seventh aspect of the present invention, in the heat pump hot water supply apparatus according to the second aspect, hot water heated by the hot water supply heat exchanger is supplied to the hot water supply heat exchanger, and hot water heated by the hot water supply heat exchanger is supplied to the hot water storage tank. A hot water storage circuit to be injected into the hot water supply, and a hot water temperature detecting means for detecting the temperature of the hot water led from the heat exchanger for hot water supply to the hot water storage tank. Reduces the target frequency.
According to an eighth aspect of the present invention, in the heat pump hot water supply apparatus according to the seventh aspect, the target frequency is reduced in accordance with the tapping temperature.

  According to the present invention, an optimum target frequency that does not cause an overload state can be determined, and the start-up time can be shortened.

The heat pump hot water supply apparatus according to the first embodiment of the present invention includes an outside air temperature detecting means for detecting an outside air temperature, an incoming water temperature detecting means for detecting an incoming water temperature supplied to a hot water supply heat exchanger, and heat exchange for hot water supply. Target hot water temperature setting means for setting the hot water temperature after heat exchange in the cooler, and frequency determining means for determining the operating frequency of the compressor. In the frequency determining means, the target frequency at the start of the compressor is It is determined using the target hot water temperature set by the target hot water temperature setting means, the outside air temperature detected by the outside air temperature detecting means, and the incoming water temperature detected by the incoming water temperature detecting means. According to the present embodiment, since the target frequency at the time of start-up is determined from the outside air temperature, the incoming water temperature, and the target hot water temperature, an overload state can be reliably predicted, so an optimal target that does not cause an overload state The frequency can be determined, and the start-up time can be shortened without impairing the reliability of the compressor due to high pressure, liquid back, high / low pressure difference, oil level and the like.
According to the second embodiment of the present invention, in the heat pump hot water supply apparatus according to the first embodiment, in the frequency determining means, when the outside air temperature is not less than the first set temperature and not more than the second set temperature, The target frequency at the start of the compressor is determined according to the temperature. According to the present embodiment, if the outside air temperature is in a range that does not cause an overload, the target frequency at startup is determined according to the incoming water temperature, so the optimal frequency according to the incoming water load is determined as the target frequency. be able to.
According to the third embodiment of the present invention, in the heat pump water heater according to the second embodiment, the frequency determining means increases the target frequency when the outside air temperature is equal to or lower than the first set temperature. . According to the present embodiment, when the outside air temperature is too low, the frequency can be increased to compensate for the lack of capacity and the startup time can be shortened.
The fourth embodiment of the present invention increases the target frequency in accordance with the outside air temperature in the heat pump hot water supply apparatus according to the third embodiment. According to the present embodiment, it is possible to finely set an increase in capacity when the outside air temperature is low.
According to a fifth embodiment of the present invention, in the heat pump water heater according to the second embodiment, the frequency determining means lowers the target frequency when the outside air temperature is equal to or higher than the second set temperature. . According to the present embodiment, when the outside air temperature is high, an overload state can be avoided by reducing the target frequency.
In the heat pump hot water supply apparatus according to the fifth embodiment, the sixth embodiment of the present invention increases the target frequency according to the outside air temperature. According to the present embodiment, it is possible to finely set the capacity reduction when the outside air temperature is high.
According to a seventh embodiment of the present invention, in the heat pump hot water supply apparatus according to the second embodiment, the frequency determining means reduces the target frequency when the tapping temperature is equal to or higher than the set temperature. According to the present embodiment, when the tapping temperature is high, an overload condition can be avoided by reducing the target frequency.
In the heat pump hot water supply apparatus according to the seventh embodiment, the eighth embodiment of the present invention reduces the target frequency according to the tapping temperature. According to the present embodiment, it is possible to finely set a decrease in capacity when the hot water temperature is high.

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.
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 10A for detecting the temperature of the compressor 11, a temperature sensor 10B for detecting the refrigerant temperature discharged from the compressor 11, a pressure sensor 10C for detecting the refrigerant pressure discharged from the compressor 11, and an evaporator. 14D is provided with a temperature sensor (outside air temperature detecting means) 10D for detecting intake air. Here, the temperature sensor 10 </ b> A detects cold start, and the pressure sensor 10 </ b> C detects abnormality of the compressor 11 or the heat pump circuit 10.

Next, a hot water storage circuit of the heat pump hot water supply apparatus according to this embodiment will be described.
A bottom pipe 21 of the hot water storage tank 20 is connected to a water supply pipe 32 such as a water pipe via a flow rate adjustment valve 31. The bottom piping 22 of 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. 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.
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. Further, a water discharge pipe 35 branched from the bottom pipe 21 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. This tapping circuit is provided with a flow sensor 30A for detecting the tapping amount and a temperature sensor 30B for detecting the tapping temperature.
The hot water storage tank 20 is provided with a plurality of temperature sensors 20A, 20B, 20C for detecting the amount of hot water in the hot water storage tank 20. In addition, a temperature sensor (incoming water temperature detecting means) 20 </ b> D for detecting the incoming water temperature derived from the bottom pipe 22 of the hot water storage tank 20 is provided in the inflow side pipe of the water pipe 12 </ b> A. The upper circulation pipe 24 is provided with a temperature sensor (hot water temperature detecting means) 20E for detecting the hot water temperature derived from the water pipe 12A.

Hereinafter, the hot water storage operation of the heat pump hot water supply apparatus according to the present embodiment will be described.
When the temperature sensors 20A, 20B, and 20C in the hot water storage tank 20 detect that the amount of hot water in the hot water storage tank 20 has become a predetermined amount or less, the heat pump circuit 10 is operated to start the hot water storage operation.
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 guided to the water pipe 12A through the bottom pipe 22, and the hot water heated by the water pipe 12A passes through the upper circulation pipe 24. It is returned to the hot water storage tank 20.
The capacity control in the compressor 11 and the opening degree control in the expansion valve 13 are controlled such that the refrigerant discharge temperature detected by the temperature sensor 10B 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 function for determining the frequency at startup will be described with reference to FIG.
FIG. 2 is a block diagram illustrating a frequency determination control function when the compressor of the heat pump water heater according to the present embodiment is started.
The frequency determining unit 40 includes a specified frequency setting unit 41, a water load setting unit 42, an outside air load setting unit 43, and a hot water load setting unit 44. In the specified frequency setting means 41, the reference operating frequency at the time of start-up as a reference is set in advance by the target hot water temperature setting means 20R. Here, the target hot water temperature setting means 20R is a temperature set by a remote controller or the like. The incoming water load setting means 42 is divided into a plurality of sections according to the incoming water temperature, and the frequency that increases or decreases in each of the sections is set. That is, the incoming water load setting means 42 is set to decrease the specified frequency if the incoming water temperature is higher than the standard temperature, and to increase the specified frequency if the incoming water temperature is lower than the standard temperature. The outside air load setting means 43 is divided into a plurality of sections according to the outside air temperature, and the frequency that increases or decreases in each section is set. For example, in the outside air load setting means 43, a first set temperature and a second set temperature are provided, and the outside air temperature is changed between the first set temperature and the second set temperature as a standard temperature and the specified frequency is changed. However, the specified frequency is increased as a low load temperature at a temperature lower than the first set temperature, and the specified frequency is decreased as a high load temperature at a temperature higher than the second set temperature. The hot water load setting means 44 sets a frequency to be corrected according to the hot water temperature. That is, in the hot water load setting means 44, when the hot water temperature exceeds the set value, it is determined that the state is an overload state and the frequency is decreased. In the hot water load setting means 44, when the temperature falls below a predetermined temperature range, it may be determined that the compressor capacity is insufficient and the frequency is increased.
Further, the frequency determination means 40 has a water load determination means 45, an outside air load determination means 46, a basic frequency determination means 47, and a hot water load correction determination means 48.

In the incoming water load determining means 45, the incoming water load is determined from the incoming water temperature detected by the temperature sensor (incoming water temperature detecting means) 20D and the table set by the incoming water load setting means 42. The outside air load determining means 46 determines the outside air load from the outside air temperature detected by the temperature sensor (outside air temperature detecting means) 10D and the table set by the outside air load setting means 43.
In the basic frequency determining means 47, the basic frequency is calculated by adding or subtracting the frequency according to the load determined by the incoming water load determining means 45 and the outside air load determining means 46 to the operation frequency preset by the specified frequency setting means 41. decide.
The hot water load correction determining means 48 determines whether or not the hot water temperature detected by the temperature sensor (hot water temperature detecting means) 20E is the correction target temperature set by the hot water load correction setting means 44, and correction is necessary. The correction frequency is determined.
In the target frequency determining means 49, the target frequency is determined by the basic frequency determining means 47 and the tapping load correction determining means 48. The compressor start control means 50 controls the compressor 11 with the target frequency determined by the target frequency determination means 49.

FIG. 3 is a flowchart showing a flow of frequency determination when the compressor of the heat pump water heater according to this embodiment is started.
At the time of starting the compressor, first, a target hot water temperature signal is received, the incoming temperature is received by a temperature sensor (incoming water temperature detecting means) 20D, the outside temperature is detected by a temperature sensor (outside air temperature detecting means) 10D, and the temperature sensor (outlet temperature detecting means). ) Detect the hot water temperature at 20E.
First, in step 1, a specified frequency is determined based on the received target hot water temperature signal, and in step 2, a basic frequency is determined from the detected incoming water temperature. If the outside air temperature is lower than the first set temperature (step 3), a change is made to increase the fundamental frequency (step 5). If the outside air temperature is higher than the second set temperature (step 4), the basic frequency is changed (step 6).
On the other hand, when the tapping temperature is higher than the set temperature (step 7), a change is made to lower the fundamental frequency (step 8).
As described above, the target frequency at the time of starting the compressor is determined.

FIG. 4 is a graph showing the frequency when the compressor of the heat pump water heater according to this embodiment is started.
As shown in FIG. 4, when the outside air temperature is in a standard region between the first set temperature and the second set temperature, the target frequency is basically determined by the incoming water temperature. However, in the low load region where the outside air temperature is lower than the first set temperature, the frequency is increased in accordance with a decrease in the outside air temperature, so the target frequency is determined by the incoming water temperature and the outside air temperature. In addition, in a high load region where the outside air temperature is higher than the second set temperature, the frequency is lowered according to the rise in the outside air temperature, so the target frequency is determined by the incoming water temperature and the outside air temperature.
Further, when the tapping temperature is higher than the set temperature, correction is performed so as to lower the target frequency.
In addition, although the said Example demonstrated the case where it had a hot water storage tank, you may be the instantaneous water heater type heat pump hot-water supply apparatus which takes out hot water heated with the heat exchanger for hot water supply as it is.

  As described above, the present invention can be applied not only to the operation of boiling a hot water storage tank in a heat pump water heater, but also to an instantaneous water heating operation in which hot water heated by a heat exchanger for hot water supply is discharged as it is, and the heat pump hot water supply of the present invention In addition to the hot water supply function, the apparatus is also suitable for an apparatus having, for example, a bathtub hot water supply function, a heating function, and a drying function.

The circuit block diagram of the heat pump hot-water supply apparatus by one Example of this invention The block diagram which shows the frequency determination control function at the time of the compressor starting of the heat pump hot-water supply apparatus by a present Example The flowchart which shows the flow of the frequency determination at the time of the compressor starting of the heat pump hot-water supply apparatus by a present Example. The graph which shows the frequency at the time of the compressor starting 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 Rotor 13A Main expansion valve 14 Evaporator 20 Hot water storage tank 20D Temperature sensor (incoming water temperature detection means)
20E Temperature sensor (Tapping temperature detection means)
22 Bottom piping 24 Top circulation piping 40 Frequency determining means

Claims (8)

  A heat pump hot water supply apparatus having 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 the operating frequency of the compressor is variable, and detects an outside air temperature Detection means, incoming water temperature detection means for detecting the incoming water temperature supplied to the hot water supply heat exchanger, target hot water temperature setting means for setting the hot water temperature after heat exchange in the hot water supply heat exchanger, Frequency determining means for determining an operating frequency of the compressor, wherein the frequency determining means determines a target frequency when the compressor is started up as a target hot water temperature set by the target hot water temperature setting means and the outside air. A heat pump hot water supply apparatus, wherein the heat pump hot water supply device is determined using an outside air temperature detected by a temperature detecting means and an incoming water temperature detected by the incoming water temperature detecting means.   In the frequency determining means, when the outside air temperature is not lower than a first set temperature and not higher than a second set temperature, a target frequency at the time of starting the compressor is determined according to the incoming water temperature. The heat pump hot water supply apparatus according to claim 1.   The heat pump hot-water supply apparatus according to claim 2, wherein the frequency determining means increases the target frequency when the outside air temperature is equal to or lower than a first set temperature.   The heat pump hot-water supply apparatus according to claim 3, wherein the target frequency is increased according to the outside air temperature.   The heat pump hot-water supply apparatus according to claim 2, wherein the frequency determining means reduces the target frequency when the outside air temperature is equal to or higher than a second set temperature.   The heat pump hot water supply apparatus according to claim 5, wherein the target frequency is decreased according to the outside air temperature.   A hot water storage circuit for supplying hot water supplied to the hot water supply heat exchanger and injecting hot water heated by the hot water supply heat exchanger into the hot water storage tank, and being led from the hot water supply heat exchanger to the hot water storage tank The heat pump according to claim 2, further comprising a tapping temperature detecting means for detecting a tapping temperature, wherein the frequency determining means reduces the target frequency when the tapping temperature is equal to or higher than a preset temperature. Hot water supply device. The heat pump hot water supply apparatus according to claim 7, wherein the target frequency is decreased according to the hot water temperature.

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