JPH018920Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a solar heat collecting device, and particularly to a heat collecting circuit capable of protecting a hot water storage tank from excessive heat collection.

First, FIG. 1 shows a conventional solar heat collector. In the figure, 1 is a solar heat collector, 2 is a hot water storage tank, and the two are connected by a heat medium circulation line 4 including a circulation pump 3. Note that 5 and 6 are a heat exchange coil and a heat medium expansion tank inserted in the line 4, and 7 and 8 are water supply pipes and hot water supply pipes that are connected to the hot water storage tank 2 and lead to the city water supply. In addition, temperature sensors 9 and 1 are installed in the heat collector 1 and the hot water tank 2, respectively.
As is well known, the circulation pump 3 is controlled through the controller 11 based on the temperature difference detected by the temperature sensors 9 and 10.

Since such solar heat collectors are mainly used for consumer use, it is desirable that they be maintenance-free in terms of protection against freezing of the heating medium in the winter or over-collection of heat during no-load conditions in the summer.
Regarding excessive heat collection, the heat-resistant operating temperature of a hot water tank is generally limited to approximately 85℃ or below, and if heat collection continues for a long time without using hot water during the day in summer, The temperature of the water in the hot water tank easily exceeds the heat-resistant operating temperature, which may shorten the life of the hot water tank itself. Conventionally, as a countermeasure against this problem, a hot pressure valve 12 is installed as shown by the reference numeral 12 in Fig. 1, and when the temperature of the stored hot water reaches 80 to 85 degrees Celsius, the valve is automatically opened and the hot water is discharged to provide cold city water. Generally, a method is adopted in which water is replenished into the hot water storage tank 2 to ensure safety. Note that the thermopressure valve 12 operates to open the valve when the water temperature is higher than a set temperature, and to automatically close the valve when the temperature decreases. However, such a hot pressure valve 12
If this is actually adopted, if the hot pressure valve 12 operates during excessive heat collection, 1/4 to 2/3 of the hot water in the hot water storage tank 2 will be wasted and the temperature of the stored hot water will drop significantly. This poses an inconvenience in terms of use, such as not being able to supply hot water at an appropriate temperature when needed. Although it is possible to stop the circulation pump as a means of avoiding excessive heat collection in the hot water storage tank, this method is not practical because there is a risk that the heating medium will boil inside the heat collector.

This invention was developed in consideration of the above points, and aims to solve the drawbacks of the conventional method and provide an easy-to-use countermeasure against excessive heat collection.

This purpose is achieved by installing a bypass line that bypasses the hot water storage tank in the middle of the heat medium circulation line, and a port on the hot water storage tank side is always open at the branch point of this bypass line, so that the water temperature in the hot water storage tank is maintained at a predetermined level. This is achieved by inserting a three-way switching valve that is operated to open the port on the bypass line side when the temperature rises above the temperature.

This invention will be explained in detail below based on illustrated embodiments.

In FIG. 2, with this invention, a bypass line 13 that bypasses the hot water storage tank 2 is installed in the middle of the heat medium circulation line 4 in place of the hot pressure valve 12 in FIG. A switching valve 14 is inserted. The three-way switching valve 14 is a solenoid valve having a normally open port A and two switching ports B and C, and the switching of this valve is controlled by the controller 11 as follows. In other words, during steady operation, switching port B on the hot water tank side is open,
The heat medium is pumped through the heat exchanger 5 as indicated by the solid arrow, and the solar heat obtained by the heat collector 1 is applied to the hot water tank 2 to heat the hot water in the hot water tank 2. On the other hand, if the hot water temperature rises to 80 to 85 degrees Celsius, which is the heat-resistant working temperature of the hot water storage tank 2, for example because hot water is not being supplied for a long time, the controller 11 uses the detected value from the temperature sensor 10 as an input to control the valve. A switching command is output, and the three-way switching valve 14 switches so that the switching port C on the bypass line side is opened. Due to this operation, the heat medium bypasses the bypass line 13 instead of passing through the heat exchanger 5 as shown by the broken line arrow, and therefore the heat collection in the hot water storage tank is interrupted and further excessive heat collection is prevented. Ru. In this state, if the temperature of the hot water in the hot water storage tank 2 falls due to natural standing or new water supply, the three-way switching valve 5 returns to its initial position and heat collection is resumed. In this way, the hot water tank can be safely protected from excessive heat collection without wasting hot water in the tank.

Note that when the three-way switching valve 14 is switched to the bypass line side, the temperature of the heat medium circulating in the circulation line 4 rises to a certain extent. In this case, if there is a possibility that the heat medium temperature exceeds the operating temperature range of the piping system of the heat collector, a heat radiation fin 15 is provided in the piping of the bypass line 13 as shown in FIG. By dissipating heat into the atmosphere, overheating of the piping system can be avoided. Furthermore, if a fan 16 driven by a solar battery is installed opposite to the heat dissipation fin 15 and the fan 16 is automatically operated as the amount of radiation increases, heat dissipation from the fin can be further improved. Can be done effectively.

As mentioned above, this idea is a means to prevent excessive heat collection in the hot water storage tank. Therefore, it is possible to prevent excessive heat collection without wasting hot water as in the conventional method.

Although the illustrated example shows an example of a two-water circuit using a heat exchanger, a one-water circuit that does not employ a heat exchanger and directly guides hot water from a hot water storage tank to a solar heat collector and circulates the water can also be used. Of course, it can be implemented in the same way.

[Brief explanation of drawings]

FIG. 1 is a piping system diagram of a conventional device, FIG. 2 is a piping system diagram of an embodiment of this invention, and FIG. 3 is a configuration diagram of an applied example of the bypass line in FIG. 1... Solar heat collector, 2... Hot water storage tank, 3... Circulation pump, 4... Heat medium circulation line, 13... Bypass line, 14... Three-way switching valve, 15... Radiation fin as heat radiation means .

Claims (1)

[Scope of utility model registration request] In a solar heat collection device that connects a solar heat collector and a hot water storage tank with a heat medium circulation line that includes a circulation pump, and collects the solar heat obtained from the heat collector into the hot water storage tank, A bypass line is installed that bypasses the hot water storage tank, and a heat dissipation means is installed on this bypass line. At the branch point of this bypass line, a port on the hot water storage tank side is always open to raise the water temperature in the hot water storage tank to a predetermined temperature or higher. A solar heat collecting device characterized by inserting a three-way switching valve that is operated to open a port on the bypass line side when the bypass line side is opened.