JP2008116184A - Refrigerating cycle device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve reliability of a system, and to effectively use exhaust heat in a refrigerating cycle device carrying out hot water supply and air-conditioning. <P>SOLUTION: The refrigerating cycle device is provided with a compressor 11, a parallel circuit with a hot water supply heat exchanger 12 and a heating heat exchanger 16 arranged in parallel with each other, a main refrigerant circuit comprised by annularly connecting an expansion mechanism 15 and an outdoor heat exchanger 14 in sequence, and a flow control valve 17 provided on a downstream side of the heating heat exchanger 16 in the parallel circuit to regulate a flow rate of a refrigerant. The flow control valve 17 is controlled so as to open when a high pressure becomes a set value or more. With such a composition, a desired heating capacity can be obtained while securing reliability of the refrigerating cycle device by suppressing abnormal rising of the high pressure during high temperature water inflow to the hot water supply heat exchanger 12. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a refrigeration cycle apparatus that performs hot water supply and air conditioning.

  Conventionally, in a refrigeration cycle apparatus that performs hot water supply, cold water that flows out from the lower part of the hot water tank flows into the hot water heat exchanger of the refrigeration cycle apparatus, exchanges heat with the high-temperature refrigerant discharged from the compressor, and becomes hot water. The returning operation is performed until the temperature of the water in the hot water storage tank reaches a predetermined temperature (for example, 65 ° C. in the intermediate period and summer, and 90 ° C. in the winter). In the initial stage of the refrigeration cycle, hot water is stored in the upper part of the hot water tank and cold water is stored in the lower part, that is, a temperature stratification is formed, and cold water is always supplied to the heat exchanger for hot water supply from the lower part of the hot water tank. When the hot water storage tank begins to be filled with hot water at a later stage, the temperature of the cold water in the lower part of the hot water storage tank gradually increases, and the temperature of the water supplied to the hot water supply heat exchanger of the refrigeration cycle apparatus also increases. Along with this, the refrigerant temperature at the outlet of the hot water supply heat exchanger also increased, and the high pressure increased, impairing the reliability of the refrigeration cycle apparatus.

  Therefore, in the heat pump hot water supply apparatus disclosed in Patent Document 1, if the temperature of the water entering the heat exchanger for hot water supply is higher than the standard temperature, the specified frequency of the compressor is decreased to suppress an increase in high pressure. 9 and 10 show a conventional heat pump apparatus described in Patent Document 1 and an operation flowchart thereof.

In FIG. 9, when it is detected by the temperature sensors 20A, 20B, 20C, 20D in the hot water storage tank 20 that the amount of hot water in the hot water storage tank 20 has become a predetermined value 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 led to the water pipe 12A through the bottom pipe 22, and the hot water heated by the water pipe 12A takes 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 10A maintains a preset temperature. FIG. 10 is a block diagram of frequency determination control of the compressor 11. In the specified frequency setting means 41, a reference operating frequency is set in advance. In the incoming water load setting means, the temperature range 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.
JP 2005-147542 A

  However, if the operating frequency of the compressor is reduced in order to suppress an increase in high pressure, the amount of refrigerant circulation decreases and the hot water heating capacity in the hot water heat exchanger decreases, so the desired hot water temperature and boiling time can be reduced. It had the problem that it could not be achieved.

  The present invention has been made in view of the above problems, and when high-temperature water enters the hot water heat exchanger, a part of the refrigerant flows into the heating heat exchanger connected in parallel with the hot water heat exchanger. The purpose is to reduce the high pressure to a set value and to obtain a desired heating capacity while ensuring the reliability of the refrigeration cycle apparatus.

  In order to solve the above problems, in the refrigeration cycle apparatus of the present invention, a compressor, a parallel circuit in which a heat exchanger for hot water supply and a heat exchanger for heating are arranged in parallel, an expansion mechanism, and outdoor heat exchange And a flow control valve for adjusting the flow rate of the refrigerant, provided at the downstream side of the heat exchanger for heating in the parallel circuit, and the high pressure exceeds the set value. When it becomes, it controls to open the flow control valve.

  With this configuration, it is possible to obtain a desired heating capacity while suppressing the abnormal increase in high pressure during high temperature water entry into the hot water supply heat exchanger and ensuring the reliability of the refrigeration cycle apparatus.

  According to the heat pump device of the present invention, it is possible to obtain a desired heating capacity while suppressing the abnormal increase in high pressure and ensuring the reliability of the refrigeration cycle device when high-temperature water is introduced into the hot water supply heat exchanger.

  The refrigeration cycle apparatus of the present invention is a main circuit formed by sequentially connecting a compressor, a parallel circuit in which a heat exchanger for hot water supply and a heat exchanger for heating are arranged in parallel, an expansion mechanism, and an evaporator. Provided with a refrigerant circuit and a flow rate control valve that adjusts the flow rate of the refrigerant in the parallel circuit on the downstream side of the heating heat exchanger, and opens the flow rate control valve when the high pressure exceeds the set value Control.

  Thereby, since the abnormal rise of a high voltage | pressure can be suppressed at the time of high temperature water injection to the hot water supply heat exchanger, the reliability of the refrigeration cycle apparatus can be ensured.

(Embodiment 1)
Hereinafter, Embodiment 1 of the present invention will be described in detail with reference to the drawings. In addition, the same code | symbol is attached | subjected about the same structure as background art.

  In FIG. 1, the refrigeration cycle apparatus of the present embodiment includes a compressor 11 that compresses a refrigerant to high temperature and high pressure, a high temperature and high pressure refrigerant discharged from the compressor 11 branched in two directions, and one of them is cold water in a hot water storage tank 20. The hot water supply heat exchanger 12 that cools the high-temperature and high-pressure refrigerant by exchanging heat with the other, the heating heat exchanger 16 that uses the other for indoor heating, floor heating, bathroom heating, and the like, and the heating heat exchanger in the parallel circuit An expansion mechanism that adjusts the refrigerant circulation amount provided on the side of 16 and the refrigerant that flows out of the hot water radiator 12 and the refrigerant that flows out of the heating heat exchanger 16 and then expands under reduced pressure. 15 and an evaporator 14 that absorbs heat from the atmosphere by exchanging heat with the air flowing from the outdoor fan 18.

In the operation of supplying hot water, the cold water flowing out from the lower part of the hot water storage tank 20 flows into the hot water supply heat exchanger 12 of the refrigeration cycle apparatus, exchanges heat with the high-temperature refrigerant discharged from the compressor 11, and becomes hot water. The operation of returning to is continued until the temperature of the water in the hot water storage tank 20 reaches a predetermined temperature (for example, 65 ° C. in the intermediate period, summer, and 90 ° C. in the winter). In the initial stage of the refrigeration cycle, hot water is stored in the upper part of the hot water storage tank 20 and cold water is stored in the lower part, that is, a temperature stratification is formed, and cold water is always supplied from the lower part of the hot water storage tank 20 to the hot water supply heat exchanger 12. However, in the latter half of the operation, the temperature of the cold water at the lower part of the hot water storage tank 20 rises, the temperature of the water entering the hot water supply heat exchanger 12 of the refrigeration cycle apparatus becomes high, and an abnormal increase in high pressure is caused. Here, the reason why the high pressure rises when the incoming water temperature to the hot water supply heat exchanger 12 of the refrigeration cycle apparatus increases will be described with reference to FIG. FIG. 2 is a pressure-specific enthalpy diagram during normal operation and when the temperature of water flowing into the hot water supply heat exchanger becomes high (at the end of boiling). When heat is exchanged between the high-temperature refrigerant and low-temperature water, if the temperature of the low-temperature water flowing into the hot water supply heat exchanger rises, the temperature of the refrigerant flowing out of the hot water heat exchanger also rises. Enthalpy increases. When the expansion mechanism is, for example, an expansion valve, the refrigerant discharged from the hot water supply heat exchanger expands under reduced pressure due to isentropic change, so that the refrigerant enthalpy at the evaporator inlet also increases. Therefore, the average density of the refrigerant held in the evaporator decreases, and the volume of the refrigerant held in the evaporator decreases because the volume of the evaporator is constant. Since the refrigerant weight in the refrigeration cycle is constant, the refrigerant that cannot be held by the evaporator due to the rise in the temperature of the water flowing into the hot water supply heat exchanger moves to the high pressure side, and thus the pressure rises. At the end of boiling, a pressure-specific enthalpy diagram in which the high pressure, the hot water supply heat exchange outlet refrigerant temperature, and the compressor discharge temperature are increased as shown by the dashed line. A control method for avoiding this abnormal increase in high pressure will be described with reference to the flowchart of FIG.

  First, the detected value of the refrigerant pressure detecting means 37 is read in S1, and it is determined whether or not the set value Pa (for example, 13 MPa) or less. If the set value Pa is not reached, the process proceeds to S2, and the control means 21 opens the flow rate control valve 17 so that the value of the refrigerant pressure detecting means 37 is equal to or less than the set value. If it is the set value Pa, the process proceeds to S3 and the operation is continued. After S2 and S3, the process returns to S1 and the flow chart in FIG. 2 is continued again until the hot water temperature in the hot water storage tank reaches a set value (for example, 65 ° C. in the intermediate period, summer, and 90 ° C. in the winter).

  In addition, although the installation place of the flow control valve 17 is the downstream side of the heat exchanger 16 for heating in FIG. 1, it may be an upstream side.

  As another alternative, the refrigerant temperature on the high pressure side (the refrigerant temperature in the pipe between the outlet of the hot water supply heat exchanger 12 and the expansion mechanism 15) as shown in FIG. 4 may be detected. That is, when the temperature of the water flowing into the hot water supply heat exchanger 12 rises, the hot water supply heat exchanger 12 outlet refrigerant temperature also rises, and the high pressure also rises, so that the high pressure becomes equal to or higher than the set value. The temperature of the refrigerant is derived in advance, and when the high pressure exceeds the set value, the flow control valve 17 is controlled to open as in the flowchart of FIG.

  As other alternative means, for example, as shown in FIG. 5, the incoming temperature of water flowing into the hot water heat exchanger (detected by the incoming water temperature detecting means 38) and the compressor frequency (detected by the compressor frequency detecting means 39). You may predict from. That is, the relationship between the temperature of the hot water supply heat exchanger, the compressor frequency, and the high pressure as shown in FIG. 6 is derived in advance by experiments or the like to estimate whether the high pressure is equal to or higher than the set value. Since the high pressure rises as the compressor frequency and the incoming water temperature to the hot water supply heat exchanger increase, the relationship shown in FIG. 6 can be derived. It is determined that the high pressure has exceeded the set value under the conditions of the compressor frequency and the incoming water temperature at which the high pressure shown in FIG. 6 is equal to or higher than the set value (above the dotted line shown in the figure). 17 is controlled to open.

  Further, conventionally, in order to suppress an abnormal increase in high pressure, the compressor frequency is reduced, the expansion valve is opened, and further, a bypass circuit for bypassing the compressor and the expansion valve is provided so that the refrigerant flows through the bypass circuit. I was doing. However, since this system is a multifunctional system that performs hot water supply and heating, the flow path where the heating heat exchanger is installed plays the role of a bypass circuit, so there is no need to newly install a bypass circuit. There are also benefits. Further, since the effect of reducing the high pressure can be obtained by slightly opening the flow control valve 17, the amount of circulation to the hot water supply heat exchanger 12 is reduced little, and there is no need to lower the compressor frequency, and the expansion mechanism. Since it is not necessary to increase the opening degree of 15, it is possible to suppress an abnormal increase in high pressure without reducing the hot water supply capacity.

(Embodiment 2)
Hereinafter, Embodiment 2 of the present invention will be described in detail with reference to the drawings. In addition, the same code | symbol is attached | subjected about the same structure as background art.

  7, the heat pump device of this embodiment is the same as the heat pump device shown in FIG. 1, except that the heat dissipating means 27 and the evaporator 14 are connected in parallel with the heating heat exchanger 16 via the secondary refrigerant pipe 26. The secondary refrigerant pipe 26 is provided with a circulation pump 25.

  Here, the control method of Embodiment 2 is demonstrated using the control flowchart figure of FIG. The steps up to S2 and S3 in the control flowchart are the same as in FIG. 3, but after opening the flow control valve in S2, the process proceeds to S4 to start the circulation pump.

  Normally, the abnormal increase in high pressure can be suppressed by detecting the abnormal increase in high pressure and opening the flow control valve 17, but a part of the high-temperature refrigerant flows through the other flow path of the parallel circuit as it is. However, the heat of the high-temperature refrigerant is wasted, so that the heat of the high-temperature refrigerant that has been wasted can be effectively used. For example, when operating in winter, when the evaporation temperature of the refrigerant falls below 0 ° C, frosting occurs on the fins of the evaporator, and conventionally the refrigeration cycle device is stopped or the expansion valve is opened to melt the frost. Therefore, while the frost was melted, hot water supply and heating could not be performed. However, by controlling with this configuration, the heat of the high-temperature refrigerant is transmitted to the evaporator 14, and frost can be generated without stopping the hot water supply or heating operation. Can be melted. Furthermore, the refrigerant boiling point rises in the evaporator throughout the summer, middle and winter seasons, and the compressor power is reduced and the COP is improved by reducing the high and low pressure difference.

  In the present embodiment, the case where the refrigerant pressure detecting means 37 is used in FIG. 7 has been described. However, as in the first embodiment, as disclosed in FIGS. 4 to 6, this embodiment is also effective when high-pressure estimation means is used.

  As described above, the first and second embodiments of the present invention have been described. However, the refrigerant used in the present invention is preferably a refrigerant that operates on the high-pressure side such as CO2 with supercriticality. This is because, in a system having a hot water supply function as in the present invention, a refrigerant operating with a high pressure side such as CO2 being supercritical is more advantageous for high-temperature heating than a refrigerant having a condensation region such as a chlorofluorocarbon refrigerant.

  The refrigeration cycle apparatus according to the present invention can be used as a refrigeration cycle apparatus such as a water heater, a refrigeration / air-conditioning apparatus, and a drying apparatus.

Configuration diagram of a refrigeration cycle apparatus in Embodiment 1 of the present invention Pressure-specific enthalpy diagram at the end of boiling in Embodiment 1 of the present invention Control flowchart of refrigeration cycle apparatus in Embodiment 1 of the present invention Configuration diagram of a refrigeration cycle apparatus in Embodiment 1 of the present invention Configuration diagram of a refrigeration cycle apparatus in Embodiment 1 of the present invention Configuration diagram of a refrigeration cycle apparatus in Embodiment 1 of the present invention Configuration diagram of a refrigeration cycle apparatus in Embodiment 2 of the present invention Control flowchart of refrigeration cycle apparatus in Embodiment 2 of the present invention Conventional refrigeration cycle diagram Control flowchart of conventional refrigeration cycle apparatus

Explanation of symbols

10 heat pump circuit 10A temperature sensor (discharge temperature detection means)
10B Pressure sensor (Discharge pressure detection means)
10C temperature sensor (outside air temperature detection means)
DESCRIPTION OF SYMBOLS 11 Compressor 12 Hot water supply heat exchanger 12A Water pipe 13A 1st on-off valve 13B Capillary tube 14 Evaporator 15 Expansion mechanism 16 Heating heat exchanger 17 Flow control valve 18 Outdoor fan 19 Use terminal 20 Hot water storage tank 20A, 20B, 20C, 20D, 20E, 20F Temperature sensor 21 Control means 22 Bottom pipe 23 First circulation pump 24 Upper circulation pipe 25 Second circulation pump 26 Secondary refrigerant pipe 27 Heat radiation means 30A Flow rate sensor 30B Temperature sensor 33 Hot water supply pipe 34 Mixing valve 35 Drain pipe 36 Refrigerant temperature detecting means 37 Refrigerant pressure detecting means 38 Incoming water temperature detecting means 39 Compressor frequency detecting means 41 Specified frequency setting means 42 Incoming load setting means 43 Outside air load setting means 44 Incoming air load determining means 45 Outside air Load determining means 46 Target frequency determining means

Claims (4)

A compressor, a parallel circuit in which a heat exchanger for hot water supply and a heat exchanger for heating are arranged in parallel, a main refrigerant circuit in which an expansion mechanism and an evaporator are sequentially connected in an annular manner, and the parallel circuit A flow control valve for adjusting the flow rate of the refrigerant, provided on the heating heat exchanger side,
A refrigeration cycle apparatus that increases the opening of the flow control valve when the high pressure of the main refrigerant circuit between the discharge side of the compressor and the inlet of the expansion mechanism is equal to or greater than a predetermined set value. The refrigerant flowing through the main refrigerant circuit is a primary refrigerant,
A secondary refrigerant circuit for connecting the heating heat exchanger, the evaporator, and a circulation pump for circulating the secondary refrigerant via a pipe;
In the heating heat exchanger and the previous evaporator, the primary refrigerant and the secondary refrigerant exchange heat,
The refrigeration cycle apparatus according to claim 1, wherein when the high pressure becomes equal to or higher than a predetermined set value, the opening degree of the flow control valve is adjusted and the circulation pump is operated. A refrigerant temperature detection means provided between an outlet of the hot water supply heat exchanger and an inlet of the expansion mechanism; and a means for estimating a high pressure from the refrigerant temperature measured by the refrigerant temperature detection means,
The refrigeration cycle apparatus according to claim 1 or 2, wherein an opening degree of the flow control valve is adjusted when the high pressure is equal to or higher than a predetermined set value. Water temperature detection means on the inlet water piping of the hot water heat exchanger, and further comprises compressor frequency detection means for detecting the frequency of the compressor,
The high pressure is estimated from the detection value of the water temperature detection means and the detection value of the compressor frequency detection means, and when the estimated value is equal to or greater than a predetermined set value, the opening degree of the flow control valve is adjusted. Or the refrigeration cycle apparatus of 2.

Images