JPS5939662B2 - solar heat collector - Google Patents

Description

Detailed Description of the Invention The present invention forms a circulation circuit for circulating heated water between a heat collector and a hot water tank, and stores the heated water heated by the heat collector in the hot water tank. The invention relates to a solar heat collector.

This type of conventional heat collection device uses a heat collection pump to collect heat when the temperature of the heated water in the collector is higher than the temperature of the heated water in the lower part of the hot water storage tank by a certain value or more until the temperature difference becomes small. The heated water is circulated, the water to be heated sent to the heat collector is heated by solar heat, and then returned to the hot water storage tank, and this process is repeated to store hot water in the hot water storage tank.

By the way, when it is cold and there is no sunlight, the water to be heated in the circulation circuit stops circulating and is likely to freeze, which may cause the heat collector or pipes to burst.

Therefore, the temperature of the heated water in the circulation circuit is detected, and when the heated water drops to a certain temperature and there is a risk of freezing, the heat collection pump is operated to circulate the heated water, and the water drain solenoid valve is activated. An anti-freeze device is activated to open the circuit and discharge heated water from the circulation circuit, thereby protecting the heat collector and piping from bursting due to freezing.

Generally, the heated water in the circulating circuit freezes when the temperature A at the detection part of the heated water in the circulating circuit is higher than the freezing temperature of the heated water (0°C), as shown in Figure 1. Also, when the outside temperature C is below 0°C, heat is radiated to the outside air from the least insulated part of the circulation circuit, and the temperature of the heated water in that part drops to 0°C (point A), as shown in Figure 2. As shown in Figure 2, even if the outside air temperature is 0°C or higher, there are cases where the temperature of the heated water in the collector drops to 0°C due to radiation cooling from the collector (point B). The places that freeze differ depending on the time.

In this way, once freezing occurs in a place other than the heating water temperature detection part of the circulation circuit, the antifreeze device is activated, and even if the heat collection pump is operated, the heated water may not be circulated or the water may be drained. Even if the solenoid valve is activated, the water may not be drained, leading to complete freezing and damage to the heat collector and piping in the circulation circuit.

Conventionally, as a countermeasure against this problem, the detection temperature of the heated water that activates the anti-freezing device is set to a high value. It had the disadvantage that the antifreeze device would be activated due to radiation cooling even though there was no radiation cooling.

Another possibility is to detect the temperature of the heated water at multiple points in the circulation circuit and activate the antifreeze device depending on the lowest detected temperature, but this would require wiring work as the number of sensors increases. In addition to being troublesome, even if the number of sensors is increased, it is not always possible to detect the temperature at the lowest temperature in the circulation circuit, so it is not practical.

The present invention was made in view of the above facts, and detects the temperature of the heated water in the circulation circuit and the outside air temperature, and freezes the heated water at a higher temperature when the outside air temperature is low than when the outside air temperature is high. It is characterized by being equipped with a control device that drives the prevention device, and it is only necessary to consider the temperature drop due to radiation cooling, when the outside temperature is high during the middle seasons such as spring and autumn, when heat conduction can cause the heated water temperature to freeze. Under such conditions, the anti-freezing device operates at a low detection temperature of the heated water to prevent unnecessary activation of the anti-freezing device, and in conditions such as winter when the outside temperature is low and the heated water is likely to freeze due to heat conduction, the anti-freezing device operates at a low detection temperature of the heated water. The purpose of the prevention device is to operate at a high heated water detection temperature to prevent heated water other than the detection part from freezing and to protect the heat collector and piping from bursting, and is an economical and efficient method. A solar heat collector equipped with a good antifreeze control device is provided.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 3 shows a system diagram of a solar heat collector to which the present invention is applied, in which 1 is a heat collector, 2 is a hot water storage tank, and the heat collector 1 and the hot water storage tank 2 are heat collection pumps that also serve as antifreeze devices. A circulating circuit 6 for heated water stored in the hot water storage tank 2 is formed by connecting an outgoing pipe 4 and a return pipe 5, which are interposed in the hot water storage tank 2.

7 is a water supply pipe connected to the lower part of the hot water storage tank 2, 8 is the hot water storage tank 2
This is the hot water pipe connected to the top of the pipe.

9 is a heat collection pump 30 control device, and a heat collection sensor 10 detects the temperature of the heated water near the return pipe 5 in the heat collector 1 and the temperature of the heated water near the outgoing pipe 4 in the hot water storage tank 2, respectively. ,11
, an antifreeze sensor 12 that detects the temperature of heated water in the heat collector 1 , and an outside air sensor 13 .

FIG. 4 shows the electric circuit of the control device 9, in which a heat collection thermostat 16 and an antifreeze thermostat 17 are connected between busbars 14 and 15 to which a DC low voltage is supplied, and a busbar 18 to which an AC voltage is supplied. 19, the heat collection pump 3 is connected via relay switches 201 and 211.

The heat collecting thermometer 16 receives the heat collecting sensor 10° 11 as an input, and when the detected temperature of the heat collecting sensor 10 is higher than the detected temperature of the heat collecting sensor 11 by a certain value (for example, 10°C) or more, the difference therebetween is a certain value (for example, 2 It consists of a well-known differential temperature thermometer that excites the relay 20 for driving the relay switch 201 until the temperature reaches 100°C or less.

The antifreeze thermostat 17 has a bridge circuit 26 which is provided between the busbars 14° and 15 and includes an antifreeze sensor 12, an outside air sensor 13, and resistors 22 to 25, and an input terminal 271.272 is connected to an output point 261.262 of the bridge circuit 26. A differential amplifier 27 is connected with a positive feedback resistor 28 between the input terminal 271 and the output terminal 2730, and a resistor 29 is connected in series between the output terminal 273 of the differential amplifier 27 and the bus bar 15. .3
0 and a transistor 32 whose base is connected to the intermediate connection point 31 between the resistors 29 and 30 and whose emitter is connected to the bus bar 15, and whose collector is connected to the relay switch 2.
11 is connected to the bus bar 14 via a relay 21 for driving the bus.

Note that each sensor uses a negative characteristic thermistor.

According to this embodiment, when the heat collection sensors 10 and 11 detect a temperature difference of more than a certain value in the presence of sunlight regardless of the four seasons, the heat collection thermometer 16 energizes the relay 20, The heat collecting pump 3 is energized via the relay switch 201.

For this reason, the heat collection pump 3 operates and the heated water circulates.
The heated water remaining in the heat collector 1 is stored in the hot water tank 2,
The heated water newly sent to the heat collector 1 is heated here.

When the temperature difference detected by the heat collection sensors io and 1i becomes less than a certain value, the relay 20 is de-energized and the heat collection pump 3 is stopped.

In this way, when there is solar radiation, the water to be heated circulates intermittently in the circulation circuit 6, and after being heated using solar heat,
Hot water is stored in a hot water storage tank 2 and supplied through a hot water outlet pipe 8.

Moreover, when hot water is supplied, city water is newly supplied from the water supply pipe 7.

On the other hand, the antifreeze thermostat 17 monitors the temperature of the heated water detected by the antifreeze sensor 12 and the outside air sensor 13 and the outside air temperature, and energizes the relay 21 when there is a risk that the heated water may freeze. The heat collector 1, outgoing pipe 4, and return pipe 5 are protected from freezing by operating the heat collecting pump 3 and circulating the heated water.

That is, in the bridge circuit 6, the sensors 10, 11° 12 and the resistors 22 to 25 are set so that the potential of the output point 261 exceeds the potential of the output point 262 in the region below the characteristic line shown in FIG. The proportional straight line portion in which the heated water temperature T has a negative slope with respect to the outside air temperature TO is, for example, the freezing start temperatures T1 and T2 in FIGS. 1 and 2, and the outside air temperature TOI at this time.

It is determined by the relationship between TO2, and when the outside temperature TO is higher than TO2', the heated water temperature T is a constant value T2.
', and when the outside temperature To is below TO1', which is lower than TOI, the heated water temperature is set to a constant value T1'.

In this area, there is an antifreeze sensor 12 and an outside air sensor 13.
When the detected temperature enters, the output terminal 273 of the amplifier 27 becomes a high potential, and the base current flows through the transistor 32, making it conductive and exciting the relay 21.

By designing the anti-freezing thermometer 17 in this way, when the outside temperature is around 0°C, the lower the outside temperature TO, the higher the heated water temperature T the heat collection pump 3 operates to prevent freezing. For example, when the outside temperature T' is TO,2, only radiation cooling is taken into account, and when the heated water temperature T is detected as T2, the heat collector pump 3 is operated to protect the heat collector 1. In order to achieve 3 to operate circulation circuit 6
Freeze protection will be provided throughout.

Furthermore, if the outside temperature exceeds TO2', the heated water in the heat collector 1 will not freeze even if there is radiation cooling.
The heated water temperature T operated by the heat collection pump 3 is set to the lowest temperature T2/
By setting it to , it is possible to avoid unnecessary anti-freezing operation during the intermediate seasons such as spring and autumn, and it is also possible to prevent unnecessary operation when the heated water temperature T exceeds T 1 /.

The operation of the heat collecting pump 3 by the antifreeze thermostat 17 is terminated when the temperature detected by the antifreeze sensor 12 increases due to the circulation of the heated water, and the potential at the output point 261 becomes lower than the potential at the output point 262, resulting in positive feedback. Since the amplifier 27 is provided with a predetermined differential by the resistor 28, there is no possibility that the heat collecting pump 3 will perform hunting operation.

Furthermore, when there is sunlight, the resistance value of the antifreeze sensor 12 is extremely small, and the relay 21 is not excited.

FIG. 6 shows another system diagram of a solar heat collector to which the present invention is applied, in which the same parts as in FIG. 3 are given the same reference numerals.
The difference from Fig. 3 is that there are solenoid valves 33 in the outgoing pipe 4 and return pipe 5, respectively.
and 34 are inserted, and solenoid valves 3 are inserted into branch pipes 35 and 36, respectively, which are connected in the middle of the outgoing pipe 4 and the return pipe 5.
7 and 38 are interposed, an outside temperature switch 39 made of bimetal or the like is used instead of the outside temperature sensor 13, and the control device 9' controls the heat collecting pump 3 and the solenoid valves 33.
34, 37, and 38.

Fig. 7 shows the electric circuit of the control device 9', and the same parts as in Fig. 4 are given the same reference numerals, and the difference from Fig. 4 is the output point of the bridge circuit 26' of the antifreeze thermostat 17'. 26
Antifreeze thermostat 12, outside temperature switch 39, and resistors 40 to 43 are set so that the potential at output point 262' exceeds the potential at output point 262' below the characteristic line shown in FIG. Relay switch 21 driven by 21
The solenoid valves 33 and 34 are connected through the B contacts of 2, and the solenoid valves 37 and 38 as an anti-freeze device are connected between the busbars 18 and 19 through the A contacts, respectively, and the heat collecting pump 3 is connected between the bus bars 18 and 19 only through the relay switch 201.

In this embodiment, the solenoid valves 33 and 34 are normally energized and open, and the solenoid valves 37 and 38 are closed, and when there is sunlight, the heat collection pump 3 is intermittently operated to close the hot water tank. 2
Store hot water in.

In addition, when there is no sunlight and the outside temperature TO is below TO1 and the outside temperature switch 39 is closed, the heated water temperature T is T1.
or when the outside temperature T is over TO2 and the heated water temperature T is under T2 with the outside temperature switch 39 open, the relay 21 is energized and the relay switch 212 is set to a. Switch to the side, solenoid valve 33.34
When the circuit is closed, the solenoid valves 37 and 3F3 are opened, and the heated water in the circulation circuit 6 is discharged from the branch pipe 35.degree. 36, thereby protecting the circulation circuit 6 from bursting due to freezing.

In this case too, when the outside temperature is low, freezing will be prevented at a higher heated water temperature than when the outside temperature is high.
An effect similar to that of FIG. 3 can be obtained.

As described above, the present invention forms a circulation circuit for circulating heated water between a heat collector and a hot water storage tank, and stores the heated water heated by the heat collector in the hot water tank. In the
It is equipped with a control device that detects the temperature of the heated water in the circulation circuit and the outside air temperature, and drives the antifreeze device at a higher heated water temperature when the outside air temperature is low than when the outside air temperature is high. When the outside temperature is high and only the effect of radiation cooling can be taken into account, such as in the middle of winter, antifreeze operation can be performed at a low heated water temperature to prevent unnecessary antifreeze operation. When the outside temperature is low (heated water tends to freeze due to heat conduction), antifreeze operation is performed at a high heated water temperature to prevent heated water other than the detection part from freezing, making it possible to operate in all seasons. This enables appropriate and efficient antifreeze operation, eliminates the risk of the antifreeze device becoming inoperable (the circulation circuit can be protected, and is economical as there is no need to increase the number of sensors). At the same time, wiring work can be done easily.

[Brief explanation of drawings]

Figures 1 and 2 are explanatory diagrams showing characteristic examples of conventional equipment, Figure 3 is a system diagram of a solar heat collector showing an embodiment of the present invention, and Figure 4 is the control device used in Figure 3. Electrical circuit diagram, 5th
The figures are the same (characteristic explanatory diagram, Fig. 6 is a system diagram of a solar heat collector showing another embodiment of the present invention, Fig. 7 is an electric circuit diagram of the control device used in Fig. 6, Fig. 8 is 1 is a characteristic explanatory diagram. 1... Heat collector, 2... Hot water storage tank, 3... Heat collection pump, 6... Circulation circuit, 9, 9'... Control device, 12.
...Anti-freezing sensor, 13...Outside air sensor, 37,3
B...Solenoid valve, 39...Outside temperature switch.

Claims (1)

[Claims] 1 In a system in which a circulation circuit for circulating heated water is formed between a heat collector and a hot water storage tank, and the heated water heated by the heat collector is stored in the hot water storage tank, the circulation circuit A solar heat collector characterized by comprising a control device that detects the heated water temperature and the outside air temperature, and drives the antifreeze device at a higher heated water temperature when the outside air temperature is low than when the outside air temperature is high. Device.