JP2010216715A - Heat pump device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem wherein when heat exchange is performed in a radiator between intermediate temperature water stored within a hot water storage tank and a refrigerant, a COP of a refrigerating cycle device is lowered. <P>SOLUTION: By returning intermediate temperature water to an intermediate part of the radiator in accordance with the temperature within the tank without providing an additional heat exchanger, effective use of the intermediate temperature water and the COP of the refrigerating cycle device can be achieved. This heat pump device includes: an intermediate temperature water bypass circuit connected to the intermediate part of the hot water storage tank and an intermediate part of a heating portion; an intermediate temperature water control valve provided within the intermediate temperature water bypass circuit; and a hot water temperature measuring device provided in the intermediate part of the hot water storage tank to detect the temperature of hot water within the tank. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a heat pump device.

  In recent years, an apparatus using a heat pump has been used as a heating system.

  As main embodiments, a compressor, a heat exchanger for heating, an expansion device, a heat pump cycle having an atmospheric heat exchanger that absorbs atmospheric heat, and a hot water tank for storing hot water heated by a hot water supply or heating heat exchanger The water is drawn from the lower part of the hot water tank, heated by a hot water or heating heat exchanger, then returned to the upper part of the hot water tank, the hot water discharge pipe to the terminal, and the hot water at the upper part of the hot water tank are circulated. There is a heat pump device including a heat dissipation circuit that dissipates heat with a radiator or the like.

  By the way, when the heating system is operated for a long time, a large amount of unusable medium-temperature water that cannot supply a sufficient amount of heat for the heating operation is stored. In the case of a heat pump device, when heat is exchanged between the hot water and the refrigerant in the hot water supply or heating heat exchanger, the COP (coefficient of performance) decreases, resulting in an increase in running cost. For this reason, there is a problem that a heat pump device that meets the user's expectations cannot be realized.

Therefore, conventionally, a heat pump system having a hot water storage tank as disclosed in Patent Document 1 has been proposed. As shown in FIG. 8, this heat pump device includes a heat exchanger that uses atmospheric heat and a heat exchanger that uses the heat of medium-temperature water as refrigerant heating means. By performing the operation of switching between these heat exchangers, hot water can be efficiently boiled and the running cost can be improved.
Japanese Patent Laying-Open No. 2007-240151 (FIG. 1)

  However, in the heat pump device of FIG. 8, it is necessary to newly provide a heat exchanger and a switching electric expansion valve that are used only when the heat of medium temperature water is used. For this reason, there is a problem that the apparatus becomes large in size and high in cost.

  In order to solve the above-mentioned problems, the present invention returns the intermediate temperature water to the intermediate portion of the radiator according to the temperature in the hot water storage tank without providing a new heat exchanger, thereby effectively utilizing the intermediate temperature water and the heat pump device. It aims at aiming at coexistence of improvement of COP.

  In order to solve the above-described problems, a heat pump device according to the present invention includes a compressor, a radiator, an expansion device, and an evaporator connected in an annular shape in this order, and a heat pump unit that heats water by the radiator, and the heat pump. A tank for storing hot water heated by the unit, a heat dissipation circuit for removing high-temperature water from the upper part of the tank, and returning medium-temperature water to the lower part of the tank via a heat dissipation mechanism as a heater, and a lower part and an upper part of the tank A heating circuit having a heating part for heating water in the circuit by the radiator, an intermediate part of the tank and an intermediate hot water bypass circuit connected to the intermediate part of the heating part, and the intermediate hot water bypass A medium temperature water control valve provided in the circuit, and a hot water temperature measuring device for detecting the temperature of the hot water in the tank in the middle of the tank, and the heat dissipation through the medium temperature water bypass circuit In Kanden heat area of heat exchange, the greater than Kanden heat area of heat exchange with the radiator until the warm water bypass circuit through the cold water circuit it is intended.

  With this configuration, the medium-temperature water can be introduced from the intermediate portion of the radiator, so that more heat can be exchanged in a region where the heat transfer coefficient of the refrigerant is high without increasing the refrigerant temperature at the outlet of the radiator. As a result, it is possible to achieve both effective utilization of medium-temperature water and improvement of COP of the heat pump device.

  Further, the heat pump device according to the present invention includes an intermediate hot water bypass circuit that connects an intermediate portion in the tank and an intermediate portion of the radiator via a first flow control valve, a bottom portion in the tank, and the radiator. The low temperature water circuit which connects the water inlet part of this through a 2nd flow control valve is characterized by the above-mentioned.

  With this configuration, the flow rates of low-temperature water and medium-temperature water can be more optimally controlled, so that the ability of the radiator can be secured and further improvement of COP can be achieved.

  In the heat pump device of the present invention, the expansion device is an expander.

  With this configuration, the power recovered by the expander can be transmitted to the compressor, so that the COP of the heat pump device can be further improved.

  According to the heat pump device of the present invention, the heat transfer coefficient of the refrigerant can be obtained without increasing the refrigerant temperature at the outlet of the radiator by introducing medium temperature water from the middle part of the radiator without providing a new heat exchanger. More heat can be exchanged in a high area. Therefore, it is possible to achieve both effective utilization of medium-temperature water and improvement of COP of the heat pump device.

  Hereinafter, embodiments of the refrigeration cycle apparatus of the present invention will be described with reference to the drawings.

(Embodiment 1)
The configuration of the heat pump apparatus of the present invention will be described with reference to FIG.

  As shown in FIG. 1, the heat pump device of this embodiment includes a refrigerant circuit 113, a first water circuit 114, and a second water circuit 115.

  The refrigerant circuit 113 includes a compressor 101 that boosts the refrigerant, a water heat exchanger 102 that generates heat by exchanging heat between the refrigerant boosted by the compressor 101 and water, an expansion device 103 that decompresses and expands the refrigerant, The evaporator 104 that heats the refrigerant decompressed by the expansion device 103 is sequentially connected by a pipe. The refrigerant circuit 113 is filled with carbon dioxide as a refrigerant (working fluid).

  The first water circuit 114 includes a hot water storage tank 106. A water intake 112 is provided on the bottom wall of the hot water storage tank 106, and the stored water flows out from the water intake 112. The water flowing out from the water intake 112 is guided to the water heat exchanger 102 functioning as a radiator and heated. The water heated by the water heat exchanger 102 is returned to the upper part of the hot water storage tank 106 from the hot water supply port 117. By continuously performing such operations, hot water is stored in the hot water storage tank 106. On the side wall of the hot water storage tank 106, tank temperature detection means 107 is provided as temperature detection means.

  The 2nd water circuit 115 has the radiator 109 utilized as a heating apparatus. The radiator 109 functions as an indoor heating device by circulating and radiating hot water (hot water) from the hot water storage tank 106.

  Here, a state is assumed in which hot water of high temperature or medium temperature (for example, 35 ° or more) is stored up to the lower part of the hot water storage tank 106. In such a case, hot or medium hot water in the hot water storage tank 106 flows out from the water intake 112 and flows through the first water circuit 114 toward the water heat exchanger 102. Therefore, compared with the case where the lower part of the hot water storage tank 106 is filled with low temperature water, the incoming water temperature of the water heat exchanger 102 becomes higher.

  When the incoming water temperature to the water heat exchanger 102 increases, the refrigerant enthalpy at the outlet of the water heat exchanger 102 moves from point B to point B ′ as shown in FIG. As a result, the enthalpy difference in the condensation process (process in the radiator) is reduced, and the hot water supply capacity and COP are reduced. This tendency is particularly noticeable when a supercritical cycle is achieved, such as when carbon dioxide is used as the refrigerant. Therefore, it is important not to raise the incoming water temperature to the water heat exchanger 102 as much as possible in order to suppress the efficiency reduction of the refrigeration cycle apparatus.

  FIG. 4 is a diagram illustrating the relationship between the temperature of the refrigerant flowing in the radiator and the refrigerant-side heat transfer coefficient.

  As shown in FIG. 4, generally, there is a point where the refrigerant heat transfer coefficient reaches a peak at a certain refrigerant temperature, and the heat transfer coefficient in a region where the temperature is lower than the peak point is higher than the peak point. It tends to be larger than the refrigerant heat transfer coefficient in this region. That is, as a whole heat exchanger, it can be said that it is more effective to use the high temperature region than the low temperature region.

  FIG. 5 is a diagram illustrating an example of a path pattern of the heat exchanger according to the present embodiment.

  As described above, by increasing the contact heat transfer area between the refrigerant and water in the high temperature region, the amount of heat exchange in the high refrigerant heat transfer rate region can be increased. Therefore, the efficiency of the refrigeration cycle apparatus as a whole can be increased, and power consumption can be reduced.

  The means for increasing the contact heat transfer area is not only to increase the number of passes as shown in FIG. 5, but also to increase the diameter of each tube, or to make the tube cross-section flat instead of circular. Is also included.

  The operation of the first embodiment will be described using the flowchart of FIG.

  When the heating operation of the heat pump device is started, the water temperature T1 is detected by the tank temperature detecting means 107 in step 201, and the water temperature T1 is compared with the set temperature Tm1.

  If T1 ≧ Tm1 in step 201, the temperature of water flowing into the radiator from the bottom of the tank may be considerably high. In this case, the process proceeds to step 202, where the on-off valve 110 is controlled to be “OPEN”, and then the process returns to step 201. By this control, water having a relatively high temperature at the center of the tank (that is, medium-temperature water) flows into the center of the radiator through the medium-temperature water bypass circuit 108. Since it is possible to suppress an increase in the incoming water temperature to the water heat exchanger 102, it is possible to suppress a decrease in hot water supply capacity and COP.

  If T1 <Tm1 in step 201, it indicates that the temperature of the water flowing into the radiator from the bottom of the tank is low. In this case, since there is no concern that the performance of the refrigeration cycle apparatus is greatly reduced, the process proceeds to step 202, where the on-off valve 110 is controlled to be “CLOSE”, and then returns to step 201.

  As described above, the efficiency of the entire refrigeration cycle apparatus can be increased by increasing the amount of heat exchange in the region where the refrigerant heat transfer coefficient is high. As a result, power consumption can be reduced, that is, energy can be saved.

(Embodiment 2)
The second embodiment will be described.

  The difference from the first embodiment is that a first flow rate control valve 118 is provided instead of the on-off valve 110, and a second flow rate control valve 119 is provided in the middle of the low-temperature water circuit.

  The operation of the second embodiment will be described using the flowchart of FIG.

  When the heating operation of the heat pump device is started, the water temperature T1 is detected by the tank temperature detecting means 107 in step 301 and compared with the set temperature Tm1. Here, when T1 ≧ Tm1, there is a risk that the temperature of the water flowing into the radiator from the bottom of the tank is considerably high, and the routine proceeds to step 302 where the first flow control valve 118 and the second flow rate are changed. The opening degree is controlled so that the control valve 119 has an optimum flow rate, and the process returns to step 201. The opening degree of each flow control valve is determined by a table corresponding to the water temperature T1. Table 1 shows an example of the opening degree of each flow control valve with respect to the water temperature T1. That is, when the water temperature T1 is high, the opening degree of the first flow rate control valve is increased so that the amount of water flowing through the intermediate temperature water bypass circuit is increased, and the overall efficiency of the radiator is controlled.

  If T1 <Tm1 in step 301, it indicates that the temperature of the water flowing into the radiator from the bottom of the tank is low, and there is no concern that the performance of the refrigeration cycle apparatus will be greatly reduced. Control is performed so that the opening degree of the control valve 119 is fully opened, and the routine proceeds to step 304. In step 304, control is performed so that the opening of the first flow control valve 118 is fully closed, and the process returns to step 301.

  In this way, the refrigeration cycle apparatus is optimally controlled by opening the first flow rate control valve and the second flow rate control valve so that the heat exchange amount in the region where the refrigerant heat transfer coefficient is high becomes larger. Since the overall efficiency can be further increased with certainty, power consumption can be reduced, that is, energy can be saved.

Relationship between the opening degree of the first flow control valve and the second flow control valve with respect to the water temperature T1

  The heat pump apparatus according to the present invention can be used as a refrigeration cycle apparatus for various uses such as for heating water heaters and bathroom drying.

The block diagram which shows the heat pump apparatus in Embodiment 1 of this invention The block diagram which shows the heat pump apparatus in Embodiment 2 of this invention. Mollier diagram showing the refrigeration cycle in the embodiment of the present invention Relationship diagram between refrigerant temperature in radiator pipe and refrigerant heat transfer coefficient Water heat exchanger path pattern illustration Control flowchart according to Embodiment 1 of the present invention Control flowchart in Embodiment 2 of the present invention Configuration diagram showing a prior art refrigeration cycle apparatus

DESCRIPTION OF SYMBOLS 101 Compressor 102 Water heat exchanger 103 Expansion apparatus 104 Evaporator 105 Water pump 106 Hot water storage tank 107 Tank temperature detection means 108 Medium temperature water bypass circuit 109 Radiator 110 On-off valve 111 Low temperature water circuit 112 Intake port 113 Refrigerant circuit 114 1st water Circuit 115 Second water circuit 116 Tank center temperature detection means 117 Hot water supply port 118 First flow control valve 119 Second flow control valve

Claims (3)

A heat pump unit that connects a compressor, a radiator, an expansion device and an evaporator in this order, and heats the water by the radiator;
A tank for storing hot water heated by the heat pump unit;
A heat dissipation circuit that draws high-temperature water from the upper part of the tank and returns medium-temperature water to the lower part of the tank through a heat dissipation mechanism as a heater,
A heating circuit connected to a lower part and an upper part of the tank, and having a heating part for heating water in the circuit with the radiator;
A medium hot water bypass circuit connected to an intermediate part of the tank and an intermediate part of the heating part;
A medium temperature water control valve provided in the medium temperature water bypass circuit;
A hot water temperature measuring device for detecting the temperature of the hot water in the tank at the middle of the tank;
With
The tube heat transfer area for heat exchange with the radiator through the intermediate warm water bypass circuit is larger than the tube heat transfer area for heat exchange with the radiator to the intermediate warm water bypass circuit through the low temperature water circuit, Heat pump device. An intermediate hot water bypass circuit connecting the intermediate part of the tank and the intermediate part of the heating part in the heating circuit via a first flow control valve;
A low-temperature water circuit connecting the bottom of the tank and the water inlet of the radiator via a second flow control valve;
The heat pump device according to claim 1, further comprising: The heat pump device according to claim 1, wherein the expansion device is an expander.

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