JPH0412377B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a heat collector for a solar hot water supply system using a heat pump cycle.

Structures of conventional examples and their problems There is a water heater using solar heat that uses a refrigerant as a heat collection working medium to flow directly into a heat collector, and a water heater that collects solar heat and atmospheric heat by using a heat pump cycle in a heat collection circuit.

Figure 1 shows a conventional example of a solar hot water supply system using a heat pump cycle, in which a compressor 1, a feed water heating condenser 2, an expansion device 4 with a pressure balance capillary tube 3 arranged in parallel, and a heat collecting section. 5,
The accumulator 6 is sequentially connected with a refrigerant pipe 7, and a water passage 10 in a heat exchange relationship between a heat collecting circuit filled with a fluorocarbon refrigerant and sealed, a hot water storage tank 8, a water circulation pump 9, and a feed water heating condenser 2 is sequentially connected to a water pipe 11. The conventional example consists of a water supply heating circuit connected to a hot water tank 8, a water supply pipe 12 connected to a hot water storage tank 8, and a water supply circuit formed by a hot water outlet pipe 13. , a heat exchange unit 15 including a compressor 1, a feed water heating condenser 2, a water circulation pump 9,
It consists of a hot water storage unit 16 including a hot water storage tank 8, a water supply pipe 12, and a hot water outlet pipe 13.

As shown in FIGS. 2 and 3, the heat collector 14 has a flow path 17 through which the refrigerant flows inside, and a finch tube in which a plurality of plate fins 18a are provided on the outer surface of the flow path 17 as an air-side heat transfer surface 18. A heat collecting section 5 composed of a type heat exchanger, a frame 19 surrounding the heat collecting section 5, a capillary tube 3 for pressure balance, an expansion device 4, and a temperature sensing cylinder 20 that provides control input to the expansion device 4. It is composed of a storage section 21 that stores the inside.

In the solar water heating system described above, the refrigerant evaporation capacity of the heat collecting section 5 changes due to instantaneous changes in solar radiation or wind speed during heat collecting operation, so the expansion device 4 supplies an appropriate flow rate of refrigerant to the heat collecting section 5. This was an issue in terms of system stability and heat collection operation efficiency.

Figure 4 shows the refrigerant outlet temperature of a collector using a Finch-Ube heat exchanger when the outside air wind speed changes.
The _time constant τa when the outside air wind speed decreases instantaneously (point a) is the time constant τb when the outside air wind speed instantaneously increases (point b).
smaller.

When a temperature-type automatic expansion valve is used as the expansion device 4, the response of the expansion valve is slow, and when the outside air wind speed or the amount of solar radiation suddenly decreases, the flow rate of refrigerant to the heat collecting section 5 becomes temporarily excessive, causing compression. There was a risk that the compressor would be damaged due to the liquid refrigerant returning to the machine 1, causing problems in terms of reliability and durability of the equipment.

Purpose of the Invention The present invention solves the conventional problems as described above, and aims to improve the reliability and durability of equipment by improving responsiveness to load fluctuations caused by instantaneous changes in solar radiation or outside air wind speed. It is something.

Composition of the Invention In order to achieve this object, the present invention provides a heat collecting section consisting of a flow path through which a refrigerant flows directly as a heat collecting working medium and an air-side heat transfer surface, a first heat collecting section and a second heat collecting section. are connected in series, and the first heat collecting part is arranged on the upstream side of the refrigerant flow path and the second heat collecting part is arranged on the downstream side of the refrigerant flow path, and the first heat collecting part is A finch-tube heat exchanger with a large heat transfer area on the air side is used, and the second heat collecting section is configured by thermally connecting a refrigerant flow path to a frame surrounding the first heat collecting section. The structure is such that the response speed is slower than that of the first heat collecting section with respect to changes in the amount of solar radiation and the wind speed of outside air.

This configuration reduces the response speed of the collector when the amount of solar radiation or the wind speed of outside air changes suddenly.
This is intended to improve the ability to follow load fluctuations by matching the response speed of the expansion device.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 5 and 6. Note that the same parts as in the conventional example are denoted by the same numerals, and description thereof will be omitted.

Reference numeral 22 denotes a first heat collecting section composed of a Finch-Eube heat exchanger, and reference numeral 23 indicates a frame 24 surrounding the first heat collecting section 22.
A second heat collecting part configured by thermally connecting a flow path 17 through which a refrigerant flows to a holding part 25 provided on the inner surface of the refrigerant flow path in each of the first and second heat collecting parts 22 and 23. 17, 17 are connected in series and arranged so that the flow path 17 of the second heat collecting section 23 is on the downstream side.

Reference numeral 26 denotes a heat collecting part composed of a first heat collecting part 22 and a second heat collecting part 23, and 27 shows an expansion device 4 in which a capillary tube 3 for pressure balance is arranged side by side, the first heat collecting part 22, and a frame. This is a heat collector in which a second heat collecting part 24 and a second heat collecting part 23, which also serves as the second heat collecting part 24, are sequentially connected by refrigerant piping.

Next, the operation of a solar water heating system using this heat collector will be explained. The high-temperature, high-pressure refrigerant gas compressed by the compressor 1 flows into the feed water heating condenser 2, and the low-temperature water sent by the water circulation pump 9 is heated and heated by the condensation heat of the refrigerant. On the other hand, the refrigerant liquefied by releasing the heat of condensation is depressurized through the expansion device 4 and the pressure balance capillary tube 3, and is reduced in pressure to the first heat collecting section 22.
The heat flows into the second heat collecting section 23 , absorbs solar heat and atmospheric heat due to solar radiation, becomes evaporated and gasified, and returns to the compressor 1 through the accumulator 6 . This cycle is repeated in sequence to heat and raise the temperature of the water in the hot water storage tank 8.

In this embodiment, the first heat collecting section 22 is a finch-tube heat exchanger that is lightweight, has a small heat capacity, and has a large heat transfer area on the air side. The section 23 is a heat exchanger configured by thermally connecting the flow path 17 to a frame with a large heat capacity surrounding the first heat collecting section 22, and has a large time constant with respect to load fluctuations. Therefore, as shown in Figure 7, when the outside air wind speed or the amount of solar radiation suddenly decreases (point a), the time constant τa' is larger than the conventional τa (τa'> τa), and when the outside air wind speed increases instantaneously The time constant τb' at (point b) is larger than τb of the conventional example (τb'>τb).

By increasing the time constant of the heat collector in this way, the thermostatic automatic expansion valve can supply an appropriate refrigerant flow rate in response to load fluctuations, improving system stability, equipment reliability, and durability. Not only can improvements be achieved, but it also eliminates the need for high-cost thermostatic expansion valves with fast response speeds, making it possible to use low-cost thermostatic expansion valves for practical use, providing an inexpensive system. become able to.

Furthermore, the frame 19, which conventionally had the role of simply protecting the heat collecting section 5 and accommodating the expansion device 4, etc., also functions as the second heat collecting section 23 in this embodiment, so that the outer shape of the heat collector is Even though the dimensions are the same, the area of the heat collecting part is expanded, and the increased amount of heat collected increases the temperature of the hot water and improves operational efficiency, which improves economic efficiency.

Effects of the Invention As described above, the heat collector of the present invention (1) can be matched with an expansion device without deteriorating heat collection performance, and the reliability and durability of the device can be improved by preventing liquid return.

(2) It is possible to use a low-cost thermostatic automatic expansion valve, and an inexpensive system can be provided.

(3) Even if the external dimensions of the heat collector remain the same, the heat collecting area can be expanded, and the increased amount of heat collected improves operating efficiency and economic efficiency.

The effects are great.

[Brief explanation of drawings]

Figure 1 is a configuration diagram of a solar hot water supply system using a general heat pump cycle, Figure 2 is a perspective view of a conventional heat collector, Figure 3 is a plan view of a conventional heat collector, and Figure 4 is a load fluctuation characteristic diagram of a conventional heat collector, FIG. 5 is a plan view of a solar heat collector showing an embodiment of the present invention, and FIG. 6 is a diagram A-A of the second heat collecting section in FIG. The line sectional view and FIG. 7 are load fluctuation characteristic diagrams of a heat collector according to an embodiment of the present invention. 5, 26... heat collection section, 14, 27... heat collector,
17...Flow path, 18...Air side heat transfer surface, 19,2
4... Frame, 22... First heat collecting section, 23... Second heat collecting section.

Claims (1)

[Claims] 1. A heat collecting section composed of a flow path through which a refrigerant flows directly as a heat collecting working medium and an air-side heat transfer surface, a first heat collecting section and a second heat collecting section are connected in series, and the first heat collecting section is connected in series. The heat collecting part is arranged on the upstream side of the refrigerant flow path and the second heat collecting part is arranged on the downstream side of the refrigerant flow path, and
The first heat collecting section is a finch-tube heat exchanger with a large heat transfer area on the air side, and the second heat collecting section is configured by thermally connecting a refrigerant flow path to a frame surrounding the first heat collecting section. The second heat collecting section is a solar heat collector whose response speed is slower than that of the first heat collecting section with respect to changes in solar radiation and outside wind speed.