JPS6140892B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a solar heat collector that collects heat by directly circulating water to a heat collector, and when not collecting heat, uses the power of a heat collecting pump to operate the heat collector or The purpose of the present invention is to provide a solar heat collection device that completely prevents freezing by forcibly discharging water in a heat collection circuit.

Conventionally, there have been many solar heat collectors that collect heat by circulating water directly to the collector, but all of them are unable to drain water completely, resulting in a series of freezing accidents. FIG. 4 shows a typical example. Water in a heat storage tank 3 is circulated to the heat collector 1 by a heat collection pump 2 through a heat collection outgoing pipe 4. The heated hot water is returned to the heat storage tank 3 via the heat collection return pipe 5. A cistern 6 is provided above the heat storage tank 3, and tap water is supplied and stopped by a ball tap 7. Hot water from the heat storage tank 3 is supplied by a hot water pump 9 drawn out from the heat storage tank 3. The used hot water is supplied from the upper cistern 6 through the water supply pipe 10.

Now, as a method to prevent this system from freezing,
An air bleed valve 11 is provided at the top of the heat collection return pipe 5 exiting the heat collector 1. When the heat collecting pump 2 is stopped, the discharge pressure of the heat collecting pump 2 is no longer applied, so air is sucked in from the air vent valve 11 and the water in the heat collector 1, the heat collecting outgoing pipe 4, and the heat collecting return pipe 5 is discharged. It is designed to fall naturally to the water level inside Cistern 6. However, in reality, we rely on natural water falling, so some water may remain in the heat collector 1 or inside the pipes.
Since the vent of the air vent valve 11 is exposed to the atmosphere, the vent becomes clogged with freezing, making it impossible for water to drain out, resulting in a series of accidents in which heat collectors and pipes are severely damaged. In addition, when constructing the piping, if a trap is created, water will remain when water falls, so it is not possible to run pipes over the ridge, or if the pipe is thin due to falling water, the water cannot escape due to aerodynamics and surface tension, so the pipe must be made thicker. There were many other inconveniences. In addition to this falling water method, there was also a circulation method in which a heat collection pump was operated to circulate hot water in the heat storage tank when there was a risk of freezing, but the power of the heat collection pump was required.
This system had the disadvantage that the heated water that had been collected at such pains was used up to prevent freezing, which was contrary to energy conservation. As described above, the conventional methods were not able to drain water completely, causing freezing accidents, and were contrary to energy conservation.

The present invention improves these conventional drawbacks, and one embodiment thereof will now be described with reference to the drawings. FIG. 1 is an example in which the present invention is applied to a solar water heating system. In the figure, water in a heat storage tank 23 is supplied by a heat collection pump 22 to a heat collector 21 that collects solar heat through a heat collection outgoing pipe 24, and hot water whose temperature has been raised in the heat collector 21 is returned to the heat collector 21. A heat collection circuit that returns to the heat storage tank 23 through the pipe 25 is configured. The heat collection pump 22 is provided in a heat collection outgoing pipe 24 from the heat storage tank 23 to the heat collector 21 . In addition, the heat storage tank 23
An air layer portion 26 is provided at the upper part of the heat collector 21 , and an opening 27 of the heat collection return pipe 25 from the heat collector 21 faces this air layer portion 26 . Also, the heat collection pump 22
For example, a vane-type volumetric pump that can be operated in forward and reverse directions is used. Pressurized hot water is supplied from the heat storage tank 23 to the hot water tap 28 by a hot water pump 29 . Hot water is supplied to the hot water tap 28 directly when the temperature of the heat storage tank is high, and through the auxiliary boiler 30 when the temperature is low, but this selection is made by the hot water supply route switching valve 31. Water consumed by opening the hot water tap 28 is supplied to the heat storage tank 23 by opening the water pipe 32 with the ball tap 33 . If water is directly supplied to the upper part of the heat storage tank 23, the high temperature water accumulated in the upper part will be filled and the temperature will become low.
A communication pipe 34 is used to lead water to the lower part of the heat storage tank. 35 is a ripple prevention plate, and the heat collection return pipe 25
The hot water falling from the opening causes the water surface to sway, and the ball tap 33 prevents water from being frequently supplied in small amounts. Further, this system is controlled by a control device 36, a high temperature side sensor 37 attached to the heat collector 21, a low temperature side sensor 38 attached to the heat storage tank 23, and the like.

Next, the operation of this system will be explained. Due to the solar radiation, the temperature of the heat collector 21 rises and the temperature of the heat storage tank 2 increases.
3, the temperature difference between the high temperature side sensor 37, the low temperature side sensor 38, and the control device 3
6 starts the heat collecting pump 22. Heat storage tank 2
The water in the lower part of 3 is sent to the heat collector 21 by the heat collection pump 22 through the heat collection outgoing pipe 24. Heat collector 21
The heated water passes through the heat collection return pipe 25 and returns to the heat storage tank 23, where heat is stored sequentially from the top. When the solar radiation disappears and the temperature gap between the heat collector 21 and the heat storage tank 23 decreases, the heat collection pump 22 stops operating. When the hot water tap 28 is opened, the hot water pump 2
9 starts and supplies hot water in the heat storage tank 23. Instead of supplying hot water, the ball tap 33 operates and supplies water from the water pipe 32 to the heat storage tank 23.

Now, to explain the freezing prevention method of this system, when the temperature of the heat collector 21 falls, the high temperature side sensor 37 detects this, and when the temperature falls below a predetermined set value, the heat collection pump 22 is activated via the control device 36. Reverse it. Since the direction of water supply is reversed from that during heat collection, the heat collection outgoing pipe 24, the heat collector 21, and the heat collecting return pipe 25 gradually become negative pressure, and eventually the opening 27
More air from the air layer 26 is sucked in. And sequentially,
The water in the heat collecting return pipe 25, the heat collector 21, and the heat collecting outgoing pipe 24 is forcibly discharged by the heat collecting pump 22, and finally all of them are filled with air. Therefore, even if the outside temperature drops below the freezing point, the heat collector 21, the heat collection outgoing pipe 24, and the heat collecting return pipe 25 around it, which are exposed to the outside air and are prone to freezing, will not freeze. There isn't. Note that a simple method for controlling the reverse operation of the heat collection pump 22 is to cause the heat collection pump 22 to operate in reverse for a certain period of time when the heat collection operation is stopped.

The above is an example in which a forward/reverse pump capable of forward and reverse operation is used as the heat collecting pump 22.Next, we will use a normal pump that only sends water in the forward direction, and change the route using a switching valve. Another example in which a similar operation was carried out will be described.

In FIG. 2, the heat collecting pump 39 is constituted by a normal centrifugal pump, and feeds water only in the forward direction. A return bypass A40 is provided from the discharge side of the heat collecting pump 39 to the suction side, and from between the branch part of the bypass A40 on the discharge side and the heat collecting pump 39, further upstream from the confluence part of the bypass A40 on the suction side. A bypass B41 is provided that returns to the side merging section. An electric three-way valve 42, which is a path switching valve, is provided at the branching portion of the bypass A40, and an electric three-way valve 43 is also provided at the confluence portion of the bypass B41.

Regarding the operation, only the method of reverse operation, which is different from the previous embodiment, will be described. During normal operation, the electric three-way valves 42 and 43 are switched to circulate water in the forward direction, as shown in FIG. 3a. In the antifreeze operation, as shown in FIG. 3b, the electric three-way valves 42 and 43 are switched to open the bypass A40 and the bypass B41. Therefore, even if the heat collection pump 39 sends water in the same direction as when collecting heat, the direction of water flow in the heat collection path is reversed, and the water in the heat collection return pipe, the heat collector, and the heat collection forward pipe is forced to flow. It is discharged.

In addition, here, electric three-way valves 42 are installed at the branch part of the bypass A40 and the confluence part of the bypass B41.
and 43 were used, but forward/reverse operation is also possible using a combination of two electric two-way valves for a total of four two-way valves. In addition, by combining a 4-way valve and a 2-way valve, for example, bypass A40 and B41
Even if one four-way valve is installed at the discharge side branch of the heat collecting pump 39 and a two-way valve is installed between the confluence of the bypass A40 and the confluence of the bypass B41, forward/reverse operation is also possible. .

As is clear from the above description, the solar heat collector of the present invention provides a heat collection pump in the heat collection pipe leading from the heat storage tank to the heat collector, and also provides an air layer above the heat storage tank to connect the heat collector to the heat collector. The opening of the heat collection return pipe from Since the water in the heat transfer pipe is forcibly discharged, it has the following effects.

1 Water in the heat collection return pipe, heat collector, and heat collection out pipe is forcibly discharged, so there is no residual water and no freezing accidents occur.

2. Water can be forcibly discharged even if the piping such as the heat collection outgoing pipe or the heat collection return pipe is in a trap shape.
There are no construction restrictions, and piping over the building is also possible.

3. Because the water is forcibly discharged, there is no need to make the piping as thick as in the falling water method; in fact, thinner pipes are easier to drain water. For this reason, piping can be made at low cost, and heat radiation loss during heat collection operation is reduced.

4. To prevent freezing, the heat collecting pump only needs to be operated for a short period of time to forcefully discharge water, resulting in significant energy savings compared to conventional circulation systems.

5. Since water is forcibly discharged using a heat collection pump, no other power source is required.

Also, since the opening of the heat collection return pipe faces the air layer above the heat storage tank, air is reliably sucked in from here when the water supply direction is reversed.

As described above, the present invention has great effects compared to conventional solar heat collectors.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of an embodiment of the present invention.
FIG. 2 is a system diagram of another embodiment of the present invention.
FIG. 3 is an explanatory diagram of the operation of another embodiment, and FIG. 4 is a system diagram of the conventional example. 21... Heat collector, 22, 39... Heat collection pump,
23... Heat storage tank, 24... Heat collection outgoing pipe, 25...
Heat collection return pipe, 26... Air layer, 27... Opening, 4
0...Bypass A, 41...Bypass B, 42,
43...Electric three-way valve (route switching valve).

Claims (1)

[Scope of Claims] 1. A solar heat collection device having a heat collector that collects solar heat, a heat collection pump that circulates water to the heat collector, and a heat storage tank that stores hot water heated by the heat collector, The heat collection pump is provided in the heat collection outgoing pipe from the heat storage tank to the heat collector, and an air layer is provided in the upper part of the heat storage tank, and the opening of the heat collection return pipe from the heat collector faces this air layer. , and in order to prevent freezing, the water supply direction is reversed from that during heat collection using the heat collection pump,
A solar heat collecting device characterized in that water in a heat collection return pipe, a heat collector, and a heat collection outgoing pipe is forcibly discharged. 2. The solar heat collecting device according to claim 1, wherein a forward/reverse pump capable of forward and reverse operation is used as the heat collecting pump. 3 A bypass A that returns from the discharge side of the heat collecting pump to the suction side, and a bypass B that returns further upstream from the confluence of the bypass A on the suction side from between the branch part of the bypass A on the discharge side and the heat collecting pump. Claim 1, characterized in that a route switching valve is provided to select bypasses A and B, and the water supply direction is reversed by switching the route switching valve.
The solar heat collector described in Section 1. 4. The solar heat collection device according to claim 1, wherein the temperature of the heat collector is detected, and water is forcibly discharged only when the heat collector is not collecting heat and there is a risk of freezing.