JPS60181549A - Hot-water supplier utilizing solar heat - Google Patents

Abstract

PURPOSE:To permit to extent the operable period of the device to a seriously cold season by effecting defrosting operation through switching of a flow path switching valve, operations of a compressor and a circulating pump and the opening of an opening and closing valve when frost has adhered to a heat collector. CONSTITUTION:When the advance of frosting is detected by a frosting and defrosting detecting sensor 17, the flow path switching valve 14 is operated under operating the compressor 1 and the circulating pump 8 as they are and high-temperature gas refrigerant from the compressor 1 is sent into the heat collector 4 to melt and remove the frost. A non-return valve is employed for the opening and closing valve 16, therefore, it is opened automatically by the reverse cycle flow of the refrigerant while the refrigerant flows into a feed water heating condenser 2 through the bypass circuit 16 of an expansion device 3 and is returned to the compressor 1 after evaporating by absorbing heat from circulating water. The finish of defrosting is detected by the temperature rise of the frosting and defrosting detecting sensor 17. On the other hand, in case a water temperature in a hot-water reserving tank 7 is very low, the water temperature is reduced further by the defrosting operation and when a water temperature sensor 18, provided at the outlet of the water path of the feed water heating condenser 2, detects a temperature lower than a predetermined value, the defrosting operation is stopped and the trouble of freezing of water may be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a water heater that collects solar heat and atmospheric heat using a heat pump cycle.

Structure of conventional example and its problems Figure 1 shows a conventional example of a solar hot water supply system that uses a heat pump cycle to collect heat from solar heat and atmospheric heat. Heat collector 4
, a sealed heat collection circuit in which the accumulators 5 are sequentially connected by refrigerant piping 6, a water supply heating circuit in which the water passages of the hot water storage tank 7, circulation pump 8, and feed water heating condenser 2 are sequentially connected by water piping 9, and a hot water storage tank. Water supply pipe 10 connected to 7, pressure reducing check valve 11
, a hot water outlet pipe 12, and a safety valve 13.

In this water heater, there is a problem in which frost forms on the heat collector 4 during heat collection operation during particularly cold winter months, and as the frost progresses, the heat collection efficiency decreases drastically, and eventually heat collection operation becomes impossible. there were.

OBJECTS OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems of the conventional example and to extend the operable period to the severe cold season.

Structure of the Invention The present invention provides a heat collection circuit in which a compressor, a flow path switching valve, a feed water heating condenser, an expansion device, a heat collector, and an accumulator are sequentially connected, and the expansion device is further provided with a bypass circuit having an on-off valve. It consists of a hot water storage tank, a circulation pump, and a water supply heating circuit that sequentially connects the water passages of the water supply heating condenser. When frost forms on the water, defrost operation is performed by switching the flow path switching valve, operating the compressor and circulation pump, and opening the on-off valve.
FIG. 3 shows an embodiment of the present invention. Note that the same members as those in the conventional example are designated by the same numbers, and explanations thereof will be omitted. 14 is a flow path switching valve, and 15 is a bypass circuit having an on-off valve 16 arranged in parallel with the expansion device 3. In this embodiment, the on-off valve 16
This shows the case where a check valve is used. 17 is a frosting/defrosting detection sensor, and 18 is a water temperature sensor provided on the water passage outlet side of the feed water heating condenser 2.

The operation of this water heater will be explained next. Figure 2 shows the heat collection operation state, in which the high-pressure, high-temperature gas refrigerant discharged from the compressor 1 radiates heat to the feed water passing through a thermally connected water passage in the feed water heating condenser 2, condensing and liquefying it. Then, the pressure is reduced by the expansion device 3 and the temperature becomes low and low temperature, which enters the heat collector 4, where it collects heat from the sun and the atmosphere and evaporates, and the flow path switching valve 1
4, the heat pump is sucked into the compressor 1 from the accumulator 5, and the cycle is repeated. On the other hand, water passes from the hot water storage tank 7 through the water passage of the feed water heating condenser 2, is heated by the operation of the circulation pump 8, is heated, and returns to the hot water storage tank 7, and is repeatedly boiled to a high temperature.

When this water heater is operated to collect heat during winter, particularly during the cold season, a frosting phenomenon occurs in which moisture in the atmosphere freezes and adheres to the heat collector 4. As the heat collection operation continues, this frost grows and becomes a thermal resistance, which significantly reduces the heat collection efficiency. In this state, a defrosting operation is required to melt the frost adhering to the heat collector 4. FIG. 3 shows a state excluding fa Nr k, which will be explained below using the third quotient. When the M-defrost detection sensor 17 detects the progress of frost formation, the flow path switching valve 14 is operated while the compressor 1 and the circulation pump 8 are still operating, and the high-temperature gas refrigerant from the compressor 1 is transferred to the heat collector 4. Delivered to melt and remove frost. In this embodiment, a check valve is used as the on-off valve 16, so it is automatically opened by the reverse cycle flow of the refrigerant, and the refrigerant flows into the feed water heating condenser 2 through the bypass circuit 16 of the expansion device 3, and is circulated. It absorbs heat from the water, evaporates it, and returns to the compressor 1.

This defrosting operation uses a part of the heat of the hot water raised in the heat collection operation as a heat source, so the defrosting is completed in an extremely short time. Defrosting is finished when detected. However, if the water temperature in the hot water storage tank 7 is very low, the water temperature will drop further during the defrosting operation, causing the water temperature sensor 18 installed at the water passage outlet of the feed water heating condenser 2 to drop.
When the temperature is detected to be below a predetermined value, the defrosting operation is stopped. This prevents water from freezing and prevents equipment damage.

Effects of the invention (1) Since a portion of the hot water in the hot water storage tank whose temperature has been raised during the heat collection operation is used as a defrosting heat source, defrosting can be completed in an extremely short time.

(2) Since the defrosting operation time is short, the heat collection operation time can be lengthened, and the amount of heat collection increases.

(3) Freezing accidents can be prevented by preventing abnormal drops in circulating water temperature, improving equipment reliability.

[Brief explanation of drawings]

Figure 1 is a configuration diagram of a conventional solar hot water supply system using a heat pump cycle, Figure 2 is a system configuration diagram of the solar water supply system of the present invention during heat collecting operation, and Figure 3 is a system configuration diagram of the same system. indicates the time of defrosting operation. 1... Compressor, 2... Feed water heating condenser, 3... Expansion device, 4... Heat collector, 5
...Accumulator, 7...Hot water storage tank,
8...Circulation pump, 14...Flow path switching valve, 15...Bypass circuit, 16...
Opening/closing valve, 17... Defrosting/defrosting detection sensor, 18
...Water temperature sensor. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2

Claims (2)

[Claims] (1) A compressor, a flow path switching valve, a feed water heating condenser, an expansion device, a heat collector, and an accumulator are connected in sequence, and the expansion device is further equipped with a heat collection circuit provided with a bypass circuit having an on-off valve, and a hot water storage circuit. It consists of a tank, a circulation pump, and a feed water heating circuit that sequentially connects the water passages of the feed water heating condenser. Heat is collected by operating the compressor and circulation pump and closing the on-off valve, and the water is transferred to the collector. When frost forms, defrost operation is performed by switching the flow path switching valve, operating the compressor and circulation pump, and opening the on-off valve.If the circulating water temperature falls below a predetermined value, defrost operation is stopped. A constructed solar heat water heating system. (2) The solar water heating system according to claim 1, wherein the temperature of the circulating water is detected on the water passage outlet side of the water supply heating condenser.