JPH0686958B2 - Solar water heater - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a water heater utilizing solar heat.

2. Description of the Related Art As shown in FIG. 2, a conventional solar hot water supply system of this type includes a compressor 1, a four-way valve 8, a refrigerant-to-water heat exchanger 2, a high-pressure refrigerant pipe 3, and a check valve 5 in parallel. The expansion valve 4, the heat collector 6, the low-pressure refrigerant pipe 7, the four-way valve 8, and the compressor 1 which are mounted in this order are annularly connected to the main refrigerant circuit, the heat storage tank 9, the water circulation pump 10, the refrigerant-to-water heat exchange. The water circulation circuit is formed by sequentially connecting the vessels 2 in an annular shape.

With the above configuration, during heat collection operation, by driving the compressor 1 and the water circulation pump 10, the high-temperature, high-pressure refrigerant compressed by the compressor 1 exchanges heat with the refrigerant via the four-way valve 8. The hot water supplied to the water circulation circuit, which flows into the vessel 2 and has a heat transfer relationship, is heated and condensed and liquefied. The heated hot water is sent by the water circulation pump 10 and flows into the upper part of the heat storage tank 9. The condensed refrigerant passes through the high pressure refrigerant pipe 3,
The refrigerant reaches the expansion valve 4 in which the check valve 5 is installed in parallel, where the refrigerant cannot flow through the check valve 5, passes through the expansion valve 4 while being decompressed, and the heat collector 6 is kept in a low temperature and low pressure state. Flow into. The refrigerant flowing into the heat collector 6 absorbs heat from solar heat and atmospheric heat and evaporates. The vaporized refrigerant is configured to be sucked into the compressor 1 again through the low-pressure refrigerant pipe 7 and the four-way valve 8, and the refrigerant cycle heats the hot water in the heat storage tank 9. ing.

However, when the heat collector 6 is in a frosted state, the heat collecting ability is significantly reduced. Therefore, this frost is defrosted and heat collection is continued.

During the defrosting operation, the frosting state of the heat collector 6 is detected by the temperature sensor 18 from the refrigerant temperature at the inlet of the heat collector 6, and a signal is transmitted to the controller 19. The controller 19 energizes and switches the four-way valve 8 to reversibly circulate the refrigerant and defrost the heat collector 6. That is, the high-temperature / high-pressure refrigerant compressed by the compressor 1 does not flow into the refrigerant-to-water heat exchanger 2 because the four-way valve 8 is switched, and the low-pressure refrigerant pipe 7 during the heat collecting operation is used.
(Hereinafter referred to as low-pressure refrigerant pipes) and passes through the heat collector 6
Sent to. Since the heat collector 6 is in a frosted state, the refrigerant radiates heat to the frost and condenses and liquefies while melting. The condensed refrigerant does not easily pass through the expansion valve 4, but passes through the check valve 5 mounted in parallel, and the high-pressure refrigerant pipe 3 during the heat collecting operation
(Hereinafter, referred to as high-pressure refrigerant) and flows into the refrigerant-to-water heat exchanger 2 (however, during defrosting operation, the refrigerant and the hot water supply flow in the same direction). The heat radiated by the heat collector 6 has a temperature lower than that of the hot water supplied to the refrigerant-to-water heat exchanger 2 by the water circulation pump 10, and therefore is slightly heated by the hot water having a heat transfer relationship (this At this time, of course, the hot water is radiating heat, so that it is being sent to the upper part of the heat storage tank 9 in a state where the temperature has dropped.). The refrigerant discharged from the refrigerant-to-water heat exchanger 2 is configured to be sucked again into the compressor 1 via the four-way valve 8, and the cycle of this refrigerant is the collector 6
The conventional solar-powered hot water supply device gradually increases the temperature of the entire hot water in the heat storage tank 9 by repeating the heat collecting operation and the defrosting operation.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, in the above-described configuration, since hot water having a low temperature flows into the upper part of the heat storage tank 9 during the defrosting operation, it is possible to store hot water having a constant temperature in the heat storage tank 9. This cannot be done, and the hot-water supply water having a stable hot water temperature cannot be supplied from the heat storage tank 9, especially in a low outside air environment.

That is, during the defrosting operation, as described above, the temperature of the refrigerant may drop below the freezing point due to the heat of frost melting or heat dissipation to a low outside air environment in order to defrost the heat collector 6. When this low-temperature refrigerant flows into the refrigerant-to-water heat exchanger 2, it has a lower temperature than the hot water supplied by the water circulation pump 10 from the lower part of the heat storage tank 9 which has been heated until then. For this reason, in the refrigerant-to-water heat exchanger 2, heat is slightly transferred from the hot water to the refrigerant. Therefore, the temperature of the hot water is
It is lower than the state of the lower part of the heat storage tank 9, and is sent out to the upper part of the heat storage tank 9.

On the other hand, when the defrosting operation is finished and the heat collecting operation is started again, the hot water supplied from the lower part of the heat storage tank 9 and heated by the refrigerant-to-water heat exchanger 2 is sent to the upper part of the heat storage tank 9. Therefore, in the heat storage tank 9, the hot water is stored in a stacked state.

However, in the case of supplying the hot water stored in the heat storage tank 9, the solar water heating system of the present invention supplies water from the water supply port 12 provided at the bottom of the heat storage tank 9, and the hot water supply port provided at the top of the heat storage tank 9. Since it is configured to supply hot water from 11, the hot water is supplied at a constant temperature when stored in the heat storage tank 9 in a laminated state of temperature distribution.
It had the problem of difficulty.

In this conventional example, the water circulation pump 10 is operated during the defrosting operation, but even if the water circulation pump 10 is stopped during the defrosting operation, the temperature of the refrigerant flowing into the refrigerant-to-water heat exchanger 2 remains below the freezing point. Therefore, the hot water supply remaining in the refrigerant-to-water heat exchanger 2 freezes, and when the heat collecting operation is restarted, not only normal operation cannot be performed, but also the refrigerant-to-water heat exchanger 2 itself,
In addition, in the configuration shown in the conventional example, it is necessary to always operate the water circulation pump 10, and therefore the above problems cannot be solved. Therefore, it is not particularly described here.

The present invention solves such a conventional problem, and prevents the temperature distribution of the hot water in the heat storage tank from being accumulated in a stacked state in the solar heat utilizing hot water supply apparatus, regardless of changes in the outside air environment. The purpose is to do.

Means for Solving the Problems In order to solve the above problems, the solar heat utilizing hot water supply device of the present invention has a discharge pipe of a compressor and a pipe connecting a check valve and a refrigerant-to-water heat exchanger. In addition, a hot gas bypass circuit via a pressure reducing mechanism, a pipe connecting the refrigerant-to-water heat exchanger and the high-pressure refrigerant pipe, and a suction pipe during the defrosting operation via a solenoid valve between the suction pipe of the compressor. In order to perform the defrosting operation, it is necessary to switch the four-way valve to reversibly circulate the refrigerant as in the conventional one. The present invention controls not only the four-way valve but also a water circulation boundary pump, a solenoid valve, and a detection signal from a temperature sensor as described below. That is, as the control method, (1) the four-way valve is switched to circulate the refrigerant reversibly.

(2) At the same time, stop the water circulation pump.

(3) At the same time, open the solenoid valve of the circuit during defrosting operation.

It is equipped with the configuration.

Action The present invention, due to the above-described configuration, in the refrigerant-to-water heat exchanger even during the defrosting operation, since the refrigerant force below the freezing point flows in,
Even when the water circulation pump is stopped, the hot water supply water in the refrigerant-to-water heat exchanger does not freeze, so the defrosting operation ends and the heat collection operation starts, then the refrigerant-to-water heat exchanger. Since the hot water in the inside can be sent out to the upper part of the heat storage tank after being sufficiently heated, it is possible to reliably prevent the temperature distribution of the hot water in the heat storage tank from being accumulated in a laminated state.

Embodiments Embodiments of the present invention will be described below with reference to the accompanying drawings.

In FIG. 1, the structure of the solar heat utilizing hot water supply device, which is the point of the present invention, will be described in detail. The same parts as those of the conventional example shown in FIG.
The description is omitted.

In the route in which the refrigerant of the present embodiment circulates, between the discharge pipe of the compressor 1 and the pipe connecting the check valve 11 and the refrigerant-to-water heat exchanger 2, a hot air is introduced via a pressure reducing mechanism such as a capillary tube. A gas bypass circuit 16 is provided so as to bypass the four-way valve 8 and the check valve 11. In addition, between the pipe connecting the refrigerant-to-water heat exchanger 2 and the high-pressure refrigerant pipe 3 and the suction pipe of the compressor 1 via a solenoid valve 15 which is opened only during the defrosting operation, during the defrosting operation. The suction circuit 17 is provided, and the path through which the refrigerant circulates in this embodiment is shown by the solid line during the heat collecting operation and by the broken arrow during the defrosting operation.

That is, during the heat collecting operation, the refrigerant discharged from the compressor 1 is
Due to the pressure reducing mechanism provided in the hot gas bypass circuit 16, most of it flows through the main refrigerant circulation circuit via the four-way valve 8 and the check valve 11. In addition, since the solenoid valve 15 of the suction circuit 17 is closed during the defrosting operation, it flows through the same circulation path as the conventional example. Therefore, the heating capacity of the conventional example, which is equal to or higher than the heating capacity of the hot water supply stored in the heat storage tank 9, is maintained.

On the other hand, during the defrosting operation, the four-way valve 8 energized by the detection signal of the temperature sensor 18 is switched, and the circulation path of the refrigerant is also reversed from that during the heat collection operation.
Is stopped and the solenoid valve provided in the suction circuit 17 during defrosting operation
15 opens. In this embodiment, part of the refrigerant discharged from the compressor 1 does not flow into the four-way valve 8 but is split into the hot gas bypass circuit 16. The refrigerant flowing into the four-way valve 8 is
After that, as in the conventional example, it flows into the heat collector 6 to perform defrosting. In addition, the high temperature shunted to the hot gas bypass circuit 16
The high-pressure refrigerant flows into the refrigerant-to-water heat exchanger 2.
The refrigerant flowing out of the refrigerant-to-water heat exchanger 2 has a high-pressure refrigerant pipe 3
Before, i.e., to the inlet of the suction circuit 17 during the defrosting operation. At this time, the refrigerant that has defrosted the heat collector 6 passes through the check valve 5, flows through the high pressure refrigerant pipe 3, and reaches the inlet of the suction circuit 17 during defrosting operation as well. Since the solenoid valve 15 of the suction circuit 17 during the defrosting operation is open during the defrosting operation, the refrigerants flowing from these two directions merge and flow into the suction pipe of the compressor 1 at once.

In the above configuration, as described above, there is no decrease in heating capacity during the heat collecting operation, and during defrosting operation, the temperature of the refrigerant flowing into the refrigerant-to-water heat exchanger 2 is maintained above the freezing point for a long time. It is possible to

Therefore, when the defrosting operation is started, the water circulation pump
10 is stopped, the hot water having a low temperature as in the conventional example is not sent to the upper part of the heat storage tank 9, and further,
It is possible to reliably prevent the hot water supply remaining in the refrigerant-to-water heat exchanger 2 from being frozen and causing damage to the equipment. As a result, even if the defrosting operation is frequently performed, there is an effect that hot water having a laminated temperature distribution is not stored in the heat storage tank 9.

Here, the present example and the conventional example are compared with each other, and the ability during the heat collection operation is equal to or superior to that of the former one, and therefore is not particularly described here.

FIG. 3 shows the compressor power consumption characteristics during the defrosting operation, where the horizontal axis shows the defrosting amount and the vertical axis shows the input of the compressor 1 during the defrosting operation. Dry-bulb temperature 1.
The test was performed under the conditions of an outside air environment of 5 ° C, a wet bulb temperature of 0.5 ° C, a relative humidity of 85%, and a wind speed of 0 m / s. The former water circulation pump 10 is stopped, the capacity of the compressor is 12 cc, the latter water circulation pump 10 is in operation, and the capacity of the compressor is 8 cc.

A curve A in FIG. 3 shows the defrosting amount of this embodiment and the characteristic of the compressor 1 input, and the point B is 0.4 kg in the conventional example.
Indicates the input required to defrost.

From FIG. 3, the following tendency can be understood, and in the defrosting operation of the present embodiment, the frost on the heat collector 6 from the curve A is 0.
It is clear that the input of the compressor 1 is about 31 W for defrosting 4 kg, which is equivalent to that of the conventional example (point B).

By increasing the capacity of the compressor 1 and arbitrarily setting the capillary tube 14 in the hot gas bypass circuit 16, the refrigerant discharged from the compressor 1 during the defrosting operation is distributed to the hot gas bypass circuit 16. This is because a refrigerant equal to or more than that in the conventional example was made to flow into the heat collector 6 while flowing. Thereby, even if the water circulation pump 2 is stopped, the refrigerant-to-water heat exchanger 2
It is possible to defrost the same amount of frost as in the conventional example and to prevent an increase in the input to the compressor 1 required for defrosting, without freezing the hot water supply remaining in the. In other words, it is possible to prevent the hot water from being stored in the heat storage tank 9 in a laminated temperature distribution without lowering the defrosting efficiency.

Further, during the defrosting operation, the water circulation pump 10 is stopped, so that it does not consume power. Therefore, the effect of reducing the total power consumption during the defrosting operation can be obtained.

EFFECTS OF THE INVENTION As described above, according to the solar heat utilizing hot water supply device of the present invention, the following effects can be obtained.

(1) Even during the defrosting operation in which the four-way valve is switched and the refrigerant circulation is reversed, the water circulation pump is stopped to supply hot water having a low temperature.
Since it is not sent to the upper part of the heat storage tank, even if the defrosting operation is repeated frequently in a low outside air environment, the temperature distribution of the hot water supply is not accumulated in the heat storage tank in a stacked state, and it is always constant. There is an effect that hot water can be supplied at the temperature.

(2) During the defrosting operation, the water circulation pump stops and hot water remains in the refrigerant-to-water heat exchanger, but the high-temperature, high-pressure refrigerant discharged from the compressor causes a certain amount of hot gas bypass circuit. Since it flows and flows into the refrigerant-to-water heat exchanger, the hot-water supply water that has a heat transfer relationship with the refrigerant does not freeze, and damage to the equipment can be prevented.

(3) Since the water circulation pump is stopped during the defrosting operation, it is possible to reduce the total power consumption during the defrosting operation without lowering the efficiency of the defrosting.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration diagram of a solar water heating system according to an embodiment of the present invention, FIG. 2 is a configuration diagram for explaining a conventional example, and FIG. 3 is a conventional example and the present invention. It is a graph which compared the effect of one Example. 1 ... Compressor, 2 ... Refrigerant-to-water heat exchanger, 3 ... High-pressure refrigerant pipe, 4 ... Expansion valve, 5 ... Check valve, 6 ... Heat collector,
7 ... Low-pressure refrigerant pipe, 8 ... Four-way valve, 9 ... Heat storage tank, 10
…… Water circulation pump, 11 …… Hot water inlet, 12 …… Water inlet, 13…
Check valve, 14 Capillary tube, 15 Solenoid valve, 16 Hot gas bypass circuit, 17 Inhalation circuit during defrosting operation, 18 Temperature sensor, 19 Controller.

Claims (1)

[Claims] 1. A main refrigerant circulation circuit in which a compressor, a four-way valve, a check valve, a refrigerant-to-water heat exchanger, an expansion valve, a heat collector, a four-way valve and a compressor are annularly connected in this order, and this main refrigerant circulation. A temperature sensor is provided at the inlet of the heat collector of the circuit, and a heat storage tank, a water circulation pump, and a refrigerant-to-water heat exchanger are sequentially connected to form a water circulation circuit, and the four-way valve of the main refrigerant circulation circuit is formed. , A hot gas bypass circuit having a pressure reducing mechanism is provided in parallel with the check valve, and the outlet of the refrigerant-to-water heat exchanger and the suction pipe of the compressor are sucked at the time of defrosting operation by using a solenoid valve. When using a circuit to connect the circuit and perform a defrosting operation, the four-way valve is switched by the detection signal of the temperature sensor, the water circulation pump is stopped, and the solenoid valve is controlled to open. apparatus.