JPS6350627B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a solar heat collection system, and in particular to a system in which the ability of a circulation pump is made variable to improve heat collection efficiency and reduce power consumption.

Various types of heat collection circuits (piping systems) for this kind of solar heat collection system are currently being considered and adopted, but the present invention is particularly designed for a heat collection circuit that is open to the atmosphere. , The location that is open to the atmosphere is suitable for the location of the heat storage tank or for those placed between the heat storage tank and the heat collector.

FIGS. 1a and 1b are configuration diagrams for explaining a conventional example. FIG. 1a shows a heat storage tank whose inside is closed, and FIG. 1b shows a heat storage tank that is open to the atmosphere. To explain this, 1 is a heat collector, 2 is a heat storage tank, 3 is a circulation pump for heat collection, 4 is piping for heat collection, 5 is a tank open to the atmosphere, 6
is a heat exchanger, 7 is a cistern, 8 is a controller that controls the operation of the heat collection circulation pump 3 (hereinafter referred to as the controller), 9 is a sensor that measures the temperature T _H in the heat collector (hereinafter referred to as the heat collector) 10 is a sensor that measures the temperature T _L in the heat storage tank (hereinafter referred to as a heat storage tank sensor), K ₁ is a water supply pipe, and K ₂ is a hot water outlet pipe.

The heat medium flowing through the heat collecting circuit is usually used to prevent freezing, and the concentration of antifreeze is determined based on the lowest temperature in the area where the heat medium is installed. Water is used in areas where there is no risk of freezing. When solar radiation hits the heat collector 1, the heat collector sensor 9 collects heat and the heat collector sensor 9 is higher than the heat storage tank sensor 10 by the temperature drop ΔT of the heat collection pipe 4, and these temperatures are T _H > T _L + ΔT. At this time, the heat collecting circulation pump 3 is operated by the controller 8, and the heat medium is circulated. The heat exchanger 6 in the heat storage tank 2 warms the water in the heat storage tank 2 by circulating a heat medium. Bubbles are generated as the temperature of the heat medium increases in the heat collector 1, and as the heat medium circulates, the bubbles are released into the atmosphere in the open tank 5.

However, when the hot water supply load is light, such as when the number of heat collectors is larger than necessary compared to the heat storage tank capacity, or when the water temperature in the heat storage tank is high but no hot water is released,
Even if the heat collector collects solar heat, the water temperature in the heat storage tank remains
Since the heat medium will not circulate unless T _L is higher than the above-mentioned ΔT, the heat medium will generate bubbles, and eventually the bubbles will push the heat medium downward and overflow from the open tank 5. Therefore, the capacity of the open tank is such that it will not overflow even if the heat medium is pushed down into the open tank as described above, and will not be insufficient even if the heat collection circulation pump is operated next and releases enough bubbles to the atmosphere. . In addition, the capacity of the circulation pump for heat collection is T _H > T _L + ΔT even after the above-mentioned bubbles are generated in the heat collection circuit and the heat medium is pushed down.
Therefore, we needed something that could sufficiently release air bubbles and circulate the heat medium. In other words, it is necessary to have the ability to overcome the height difference (lifting head) between the heat collector and the heat storage tank and the resistance of the heat collection circuit piping. However, in the heat collecting circuit, after the bubbles are sufficiently released, the heat medium is filled in the heat collecting circuit, so the pump's capacity is sufficient to overcome the piping resistance of the heat collecting circuit. . For this reason, in the past, the heat medium was circulated with a pump capacity higher than that normally required during heat collection, which not only resulted in a decrease in heat collection efficiency but also resulted in wasteful power consumption.

The present invention improves this point by increasing the capacity of the circulation pump for heat collection when the heat medium generates bubbles and is pushed down or when the heat collector is empty, thereby ensuring that there are no bubbles or spaces. When detected, the capacity is reduced to reduce the power consumption of the circulation pump and prevent the heat medium from being circulated faster than necessary. The present invention will be explained below with reference to the drawings.
2 to 4 show examples of the present invention.

First, FIG. 2 will be explained. FIG. 2a is a system diagram, and FIG. 2b is a control block diagram. 20
21 is a variable capacity circulation pump for heat collection, and 21 is a flow rate sensor. Note that the same parts as in FIG. 1 are denoted by the same reference numerals. The variable capacity heat collecting circulation pump 20 uses a DC motor, a two-pole four-pole switching induction motor, or the like.

Next, the operation will be explained. If the heat collecting circuit is currently filled with a heat medium, the water level sensor WS22 will not output a signal due to the presence of the heat medium, and the relays _RY3 and 30 will not be energized by the amplifier 29 in the controller 11. RY ₃ 32 is open. In this state,
When the temperature measured by the heat collector sensor 9 and the heat storage tank sensor 10 becomes T _H > T _L +ΔT (here, ΔT is the temperature dropped by the heat collection pipe 4), that is, the heat collector 1 receives solar radiation. hits and collects heat, and the heat collector sensor 9 and the heat storage tank sensor 10 are T _H > T _L +
When ΔT is reached, comparison amplifier 2 in controller 11
5, relay RY ₁ 26 is energized and contacts RY ₁ 3
1 is closed. On the other hand, since the heat medium at this location is not yet circulating (not flowing) in the flow rate sensor FS21, no signal is sent to the amplifier 27 in the controller 11, and the relay RY ₂ 28 is not excited. For this reason, the contact
RY ₂ 33 is on the b side. b side of this contact RY ₂ , a
The sides are connected to the large capacity side and the small capacity side of the circulation pump 20, respectively. For this reason, the circulation pump 20 operates at maximum capacity. After a while, when the heat medium circulates, the flow rate sensor FS21 detects the flow, and the amplifier 27 energizes the relay RY ₂ 28, which closes the contact.
RY ₂ 33 falls to the a side, and the circulation pump 20 is operated at low capacity. When the amount of solar radiation decreases due to the sun being hidden by clouds, etc., and the values of the heat collector sensor 9 and the heat storage tank sensor 10 become T _H < T _L +ΔT, the comparator amplifier 2
5, the relay RY ₁ 26 is not energized and the contact RY ₁ 31 is opened, and the circulation pump 20 stops operating.

In addition, the temperature of the water in the heat storage tank 2 increases by collecting solar heat, and the heat collector sensor 9 and the heat storage tank sensor 10 are activated.
When T _H > T _L +ΔT does not hold, bubbles are generated from the heat medium, and these bubbles push down the heat medium in the heat collection circuit. In this case, the water level sensor WS
22 sends a signal to the amplifier 29, relay RY ₃ 30 is energized, contact RY ₃ 32 is closed, and circulation pump 2
A power supply voltage is applied to 0. In this case, since the heat medium is not circulating in the flow rate sensor FS21, it does not output a signal to the amplifier 27, so the relay RY ₂ 28 is not energized and the contact RY ₂ 33 is on the b side, and the circulation pump 20 has a large capacity. drive with

Next, the flow rate sensor FS21 senses the circulation of the heat medium, and the contact RY ₂ 33 becomes the a side, and the circulation pump 20
drive at low capacity. The generated air bubbles are released by the atmosphere open tank 5 as the heat medium circulates. Once released, since there are no air bubbles, the water level sensor WS22 senses this and stops sending a signal, the contact RY ₃ 32 is opened, and no voltage is applied to the circulation pump 20, stopping its operation. In this state, if T _H > T _L + ΔT occurs because the heat collector sensor 9 and the heat storage tank sensor 10 collect solar heat or the water temperature in the heat storage tank decreases due to hot water being tapped, the relay RY ₁ 26 is energized. The contact RY ₁ 31 is closed, and the circulation pump operates at high capacity while the flow rate sensor FS21 does not sense circulation of the heat medium, and operates at low capacity when the flow rate sensor FS21 senses circulation. As a result, the power consumption for operating the circulation pump was reduced by approximately 25 to 30%, and the atmosphere-opening tank 5
The capacity of the heat exchanger can be reduced by about 30 to 50%, and since the heat medium is always filled in the heat collection circuit, the amount of heat collected can be reduced by about 10%.
There were effects such as a % increase in sales.

Figure 3 shows a variable capacity circulation pump 20 driven by a DC motor to make the capacity stepless, and a flow rate sensor 2.
The drive is controlled by a single signal, and the pump capacity is increased when no heat medium is flowing, and is minimized when the flow is at its maximum, during which time the pump capacity is controlled steplessly. Flow rate sensor 21
The signal is amplified by an amplifier 27, and a controller 34 controls the circulation pump 20. The power supply of the controller 34 is provided by the contacts RY ₁ , RY ₃ , 31, 3 of the relays RY ₁ , RY ₃ mentioned above.
Controlled by 2. A heat storage tank serves as a tank that is open to the atmosphere.

Although the present invention has been described using a heat storage tank with a heat exchanger in a heat collecting circuit, the heat storage tank may be of an open type on the hot water (water) side, or may be open to the atmosphere without a heat exchanger. FIG. 4 shows this embodiment. Further, the flow rate sensor 21 of the present invention can be a pressure sensor. Further, in order to simplify the sensor system, the water level sensor 22 can be omitted, and the tank capacity opened to the atmosphere can be left large and used to reduce the power consumption of the circulation pump. Furthermore, even in systems where an air vent valve is installed near the heat collector and the circulation pump is stopped, the heat medium is recovered from the heat collector, the capacity is high until the heat medium is filled into the heat collector, and then the capacity is high. It may be arranged to operate at a low capacity.

As described above, according to the present invention, not only the power consumption in the circulation pump can be reduced, but also the heat collection efficiency can be improved by adjusting the circulation speed (flow rate) of the heat medium to a speed suitable for heat collection.

[Brief explanation of the drawing]

Figures 1a and b: Block diagram of a conventional solar heat collection system, Figure 2 a and b: Block diagram of the solar heat collection system of the present invention and its control block diagram, Figure 3:
Control block diagram of another embodiment, FIG. 4: Configuration diagram of another embodiment. Code, 20: Variable capacity heat collection circulation pump, 2
1: Flow rate sensor.

Claims (1)

[Claims] 1. A heat collection circuit is formed between a heat collector and a heat storage tank,
In a solar heat collection system in which a heat medium is circulated in the heat collection circuit by a circulation pump, the capacity of the circulation pump can be switched between at least two stages, and the flow of the heat medium in the heat collection circuit or A solar heat collecting system characterized in that a flow rate sensor or a pressure sensor for detecting pressure is provided, and the capacity of the circulation pump is changed in response to the output of the flow rate sensor or pressure sensor.