JPS628695B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hot water supply system using solar heat that can recover and reuse waste heat from hot water in a bathtub after taking a bath, and can also reheat a bath or boil a hot water tank.

A conventional solar hot water supply system of this type is constructed as shown in FIG. That is, the hot water obtained by increasing the temperature within the solar collector 1 is stored in the hot water storage tank 2 by operating the circulation pump 3. Therefore, hot water is supplied into the bathtub 10 from the upper part of the hot water storage tank 2 by a hot water supply device 12 . Further, a drain inlet pipe 6 equipped with a temperature sensor B is connected to the drain hole of the bathtub 10 and connected to the temperature difference control valve 4. Piping is branched from the temperature difference control valve 4, and one is connected to a heat exchanger 5 provided in the hot water storage tank 2 via a connecting pipe 7.
Furthermore, it is connected to a discharge pipe 9 and guided to the vicinity of a drain port 11 outside the hot water storage tank 2. The flow path passing through this heat exchanger 5 is an exhaust heat recovery flow path. The other constitutes a discharge path that is connected from the temperature difference control valve 4 to a discharge pipe 8 outside the hot water storage tank 2 . Further, a temperature sensor A is installed in the hot water storage tank 2 near the heat exchanger 5, and is connected to the temperature difference control valve 4 together with the temperature sensor B. That is, if the temperature T _A indicated by temperature sensor A is higher than or equal to the temperature T _B indicated by temperature sensor B (T _A ≧
T _B ), the waste water discharged from the bathtub 10 is guided by the temperature difference control valve 4 to a discharge path passing through the discharge pipe 8, and when the temperature is low (T _A < T _B ), waste heat is recovered through the heat exchanger 5. They are linked so that they are guided by the flow path. Here, the wastewater led to the discharge channel is directly discharged to the drain, but the wastewater led to the waste heat recovery channel exchanges heat with water (or hot water) near the heat exchanger 5, and the heat exchanger 5 Nearby water is warmed and discharged into the drainage ditch 11.

The disadvantages of this case are (1) Since the heat exchanger 5 and the temperature difference control valve are installed in the drainage path of the bathtub, the scale generated in the bathtub may adhere to the heat exchanger 5 and the temperature difference control valve 4. This has serious drawbacks in practical terms, such as significantly reducing heat exchange performance and clogging the temperature difference control valve 4 and heat exchanger 5, making drainage impossible.

(2) Since waste heat is recovered during the process of draining bath water, it is necessary to ensure a sufficient heat transfer area for the heat exchanger 5, which increases the size and cost of the heat exchanger.

(3) Since the bathtub water is drained each time the waste heat of the bathtub water is recovered, the water cannot be reused for washing, etc., which is uneconomical.

(4) Because the structure circulates water directly to the solar collector, there was a risk of freezing in the winter.

(5) Since there is no bath reheating system or auxiliary heating device for the hot water storage tank, it is not possible to reheat high-temperature hot water into the bathtub when the water temperature in the bathtub drops, and the hot water storage tank is not equipped in the winter. It was not possible to secure high-temperature hot water to the water heater, making it extremely difficult to use as a water heater.

It had many drawbacks.

The present invention solves these conventional drawbacks by using solar heat, which makes it possible to recover and reuse the waste heat of bath water after bathing, and also to reheat the bath and boil water in the hot water storage tank. The purpose is to provide hot water supply equipment for use.

In order to achieve this object, the present invention is configured to forcibly circulate the heat medium obtained by raising the temperature in the solar heat collector to the heat exchanger in the hot water storage tank, and to A heat medium heating device and a three-way valve are arranged in series in this order in the middle of the return pipe to the heat exchanger, and the return pipe and exhaust heat recovery are connected via the three-way valve on the downstream side of the heat medium heating device. The bath reheating route also serves as a bath reheating route and a bypass route, and a natural circulation type heat exchange device for bath water is installed in the middle of the bypass route, and the outlet pipe of the bypass route is merged with the return pipe to cool the hot water inside the hot water storage tank. It is connected to the inlet of the heat exchanger.

According to this configuration, (1) In the case of exhaust heat recovery from bathtub water, the return pipe side is closed using the three-way valve, and at the same time, the bypass path side is opened (that is, the exhaust heat recovery path is opened), and the operation of the heat medium heating device is stopped. By operating the circulation pump in a stopped state, the low-temperature heat medium that has been heat-exchanged with the water in the hot water storage tank is guided to the bypass path side as shown in Figure 2, and is transferred to the bathtub in the natural circulation heat exchange device. Heat is exchanged indirectly with the hot water, and the heated heat medium is guided to the heat exchanger in the hot water storage tank.
Heat is exchanged with water near the heat exchanger, and in the process of repeating this heat exchange cycle for a certain period of time, waste heat is recovered into the hot water storage tank.

(2) In the case of reheating a bath, open and close the three-way valve in the same manner as described above, so that the heat medium flows to the bypass path side (in this case, the reheating path), drive the circulation pump, and operate the heat medium heating device. The high-temperature heat medium heated by the heat medium heating device is guided to the bypass path side through the three-way valve, and is exchanged with the bath water by natural convection in the natural circulation heat exchange device, reheating the bath. I can do it.

(3) In the case of boiling a hot water storage tank When the solar heat contribution rate is poor in winter, or when a large amount of stable hot water is required, close the bypass route side with a three-way valve and at the same time close the return pipe side. to be opened. Next, by driving the circulation pump and operating the heat medium heating device,
The high temperature heat medium heated in the heat medium heating device exchanges heat with nearby water in a heat exchanger in the hot water storage tank.
At this time, the hot water in the hot water storage tank is heated up by gentle natural convection and circulation flow from the pump, so the hot water storage tank above the heat exchanger is heated to a uniform temperature.

An embodiment of the present invention will be described below with reference to FIGS. 2, 3, and 4. In FIGS. 3 and 4, parts that are the same as those in FIG. 2 are given the same numbers. In the figure, 13 is a hot water storage tank, which has a hot water outlet 14 provided at the top, a water supply port 16 provided at the bottom via a pressure reducing check valve 15, and a heat exchanger 17 disposed inside the tank. There is. 18 is a solar heat collector; 19 is a heat medium circulation pump; this circulation pump 19 connects the solar heat collector 18 and the heat exchanger 17;
It is provided in the middle of the outgoing pipe 20 that connects the outlet part of the pipe. A heat medium heating device 21 is provided in a part of the return pipe 23 from the solar heat collector 18 to the heat exchanger 17, and includes a heat exchanger 24, a burner 25, and the like. The three-way valve 22 is provided on the downstream side of the heat medium heating device 21, and the flow path is divided into three parts, one of which is connected to a bypass path 30 consisting of a bypass outgoing pipe 27, a heat exchanger 28, and a bypass return pipe 29. will be contacted.
The other side is connected to the bypass return pipe 2 via a connecting pipe 31.
9 and again forms a return pipe 23, which is connected to the inlet of the heat exchanger 17. The heat medium circulation path is configured as described above.

Next, by operating the circulation pump 19 and controlling the three-way valve 22 and the heat medium heating device 21, hot water is stored in the hot water storage tank 13 via each heat exchanger. 32 is a natural circulation heat exchange device provided on one side of the bathtub, and the heat exchanger 28 is disposed inside.
The heat exchanger 28 is connected to the sides of the bathtub 34 via two communication pipes 33 so that bath water naturally convects around the heat exchanger 28 . Hot water is supplied from a hot water outlet 14 in the upper part of the hot water storage tank 13 via a hot water pipe 35 to a faucet 36 and hot water taps (not shown). 37 indicates the flow of the heat medium flow due to the operation of the circulation pump 19;
38 shows the natural circulation flow of hot water in the bathtub.

Further, in this embodiment, an antifreeze solution such as ethylene glycol is used as a heat medium to prevent freezing and corrosion of the heat medium circulation path in winter.

Next, its operation will be explained.

(1) In the case of exhaust heat recovery from bathtub water When taking a bath, the average amount of hot water used in a typical household is 250 to 300/45°C. For example, if the amount of hot water stored in the hot water tank 13 is 200/80°C, Tank 1
Approximately 1/2 or more of the hot water storage capacity in No. 3 is used, which means that the lower part of the hot water storage tank 13 approximately in the middle is filled with cold water. In this state, three-way valve 2
2 to close the connecting pipe 31 and at the same time open the bypass outgoing pipe 27 (that is, communicate with the exhaust heat recovery channel side), and when the circulation pump 19 is operated for a certain period of time while the heat medium heating device 21 is stopped, The low-temperature heat medium that has been heat exchanged with the water in the lower part of the hot water tank 13 in the heat exchanger 17 passes through the solar collector 18 , the heat medium heating device 21 , and the three-way valve 22 via the circulation pump 19 to the bypass path 30 side. In the process in which the low-temperature heat medium is guided and passes through the heat exchanger 28, heat is exchanged indirectly with the high-temperature bath water within the natural circulation heat exchange device 32. The hot water, which has been heat exchanged within the natural circulation heat exchanger 32 and has a lower temperature, has a higher density and is therefore led to the lower part of the bathtub 34 through the lower connecting pipe 33. At this time, high-temperature hot water is introduced into the heat exchanger 32 from the upper communication pipe 33, thereby forming a natural circulation flow as shown by the arrow 38 in FIG. The heat medium heated in this manner is guided from the bypass return pipe 29 through the return pipe 23 and the inlet of the heat exchanger 17 to the heat exchanger 17 in the lower part of the hot water storage tank 13, and the water around the heat exchanger 17 is and performs heat exchange. By performing the heat exchange cycle for a certain period of time using, for example, timer control or heat medium temperature detection control (not shown), the exhaust heat of the hot water in the bathtub 34 can be completely recovered in the hot water storage tank 13. , it can save a lot of energy.

In particular, in winter when the solar heat contribution rate is poor, the relative average temperature difference in the natural circulation heat exchange device 32 for exhaust heat recovery increases, and the exhaust heat recovery rate increases.
Energy savings can be achieved throughout the year.

In addition, since the bath water and the heat medium indirectly exchange heat in the natural circulation heat exchanger 32, the heat exchanger 2
There is no risk of scale clogging in the chamber 8, and there is little deterioration in heat exchange performance due to scale corrosion, and stable exhaust heat recovery performance can be maintained over a long period of time.

Furthermore, since waste heat is recovered through natural circulation of the bathtub water, the bathtub water from which waste heat has been recovered can be reused for washing, etc., resulting in a water-saving effect.

Furthermore, since exhaust heat is recovered through the exhaust heat recovery path in the middle of the return pipe path of the solar collector 18, the exhaust heat recovered by the heat medium is directly exchanged with the water below in the hot water storage tank 13. Then,
The exhaust heat recovered by the heat medium is sent to the solar collector 18,
As the heat is effectively recovered in the hot water storage tank 13 without being radiated in the heat medium circulation path including the heat medium heating device 21 and the like, the exhaust heat recovery rate can be increased.

(2) In the case of reheating the bath When the temperature of the bath water drops and reheating is required, first, as shown in Figure 3, the three-way valve 22 is opened/closed and the connecting pipe 31 is closed in the same manner as described above to bypass the bath. When the heat medium is caused to flow to the path 30 side (that is, the reheating path side), the circulation pump 19 is driven, and the heat medium heating device 21 is operated, the high temperature heat medium heated by the heat medium heating device 21 is heated. Three-way valve 2
2, a bypass outgoing pipe 27, a heat exchanger 28,
It is led to the bypass path side of the bypass return pipe 29 and exchanges heat with the bathtub water by natural convection within the natural circulation heat exchange device 32. At this time, the bathtub water, which exchanges heat with the heat medium in the natural circulation type heat exchanger 32 and becomes high in temperature, becomes low density and rises, flows out into the bathtub 34 from the upper connecting pipe 33, and vice versa. Since the hot water below the bathtub 34 is guided into the heat exchanger 32 through the lower communication pipe 33, natural convection of the flow indicated by the arrow 38' in FIG. Additional bonfires will be held.

In addition, the reheating capacity can be set using the heat medium heating device 2.
It can be arbitrarily set by setting the combustion amount of one burner 25, the amount of heat medium circulation, and the heat transfer area of each heat exchanger.

Furthermore, for example, it is also possible to provide a temperature sensor (not shown) in a part of the lower communication pipe 33 to detect the boiling of the bath and automatically stop reheating.

(3) In the case of boiling a hot water tank When the contribution rate of solar heat is poor in winter or rainy weather, or when a large amount of hot water is required to be stably discharged, use the three-way valve 22 as shown in Figure 4.
By the switching operation, the flow in the bypass path 30 is closed, and at the same time, the connecting pipe 31 side is communicated,
When the circulation pump 19 and the heat medium heating device 21 are operated, the high temperature heat medium heated by the heat medium heating device 21 exchanges heat with water or low temperature hot water near the heat exchanger 17 in the hot water storage tank 13 . At this time, hot water is boiled up in the storage tank 13 by gentle natural convection and circulating flow by the circulation pump 19.
The hot water in the hot water storage tank 13 has a uniform temperature, and a large amount of hot water can be stably dispensed.

The boiling water temperature can be detected using a temperature sensor such as a thermistor (not shown) installed below the hot water storage tank 13.
You can also set it as you like and automatically stop the boiling.

As described above, the solar water heater of the present invention has the following features:
A heat medium heating device and a three-way valve are arranged in series in this order in the middle of the return pipe from the solar collector to the heat exchanger in the hot water storage tank, and a bypass path is formed that communicates with the heat exchanger via the three-way valve. By providing a natural circulation type heat exchange device for hot tub water in the middle of the bypass path, the following effects are achieved.

(1) The present invention uses a circulation pump to forcefully circulate a heat medium, and uses a natural circulation heat exchange device to indirectly recover waste heat from bath water.
Compared to conventional systems that have a heat exchanger in the drainage route, the heat exchanger is clogged with scale, making it impossible to drain water, and the efficiency of waste heat recovery is reduced due to deterioration of heat transfer due to scale corrosion. It is possible to recover waste heat from bathtub water stably over a long period of time, with little loss of energy, and significant energy savings can be achieved.

(2) Because the heat medium is forcibly circulated within the natural circulation heat exchange device to recover waste heat, the heat transfer area is smaller compared to conventional methods that recover waste heat during the drainage process. , the size of the heat exchanger can be reduced. In addition, the bath water from which exhaust heat has been recovered can be reused for washing, etc., making it possible to save water.

(3) A natural circulation heat exchange device is installed in the return pipe path of the solar heat collector, and the waste heat from the bathtub water is recovered and the waste heat is recovered into the hot water storage tank via the return pipe. There is no heat dissipation of waste heat in the heat medium circulation path in the heat medium heating device or the like, and the waste heat can be effectively recovered in the hot water storage tank, so that the waste heat recovery efficiency can be improved.

(4) Previously, when the bath water temperature dropped and the bath needed to be reheated, hot water was supplied by installing a separate bath pot or installing another water heater and pouring high-temperature water into the bath. In the present invention, by installing a natural circulation heat exchange device that has a heat medium heating function and also has an exhaust heat recovery function in the middle of the return pipe path of the solar collector, it is possible to add a bath in one system. It is now possible to recover waste heat from the fire and bathtub water.
It is possible to provide a water heater that is extremely easy to use.

Furthermore, since the natural circulation heat exchanger can serve both of the above functions, it can be manufactured at low cost.

(5) When the contribution rate of solar heat is poor in winter or rainy weather, or when a large amount of high-temperature stable hot water supply is required, conventional systems cannot be used. We installed a heat medium heating device that also serves as a heating device for reheating, so by switching the three-way valve, heat is exchanged directly with the heat exchanger below the hot water storage tank, and natural convection in the hot water storage tank and forced circulation by the pump are achieved. This makes it possible to boil hot water uniformly in a stream, making it possible to stably dispense large amounts of hot water at high temperatures.

Furthermore, since the heat medium heating device can be used both for reheating the bath and for boiling up the hot water storage tank, it can be manufactured at a much lower cost than when the heating device is installed separately.

(6) An antifreeze solution (such as ethylene glycol) can be used as a heat medium, and stable hot water supply function can be maintained throughout the year without freezing in the heat medium circulation path even in winter.

That is, in the present invention, as described above, one system device has a function of recovering the exhaust heat of bathtub water, a function of reheating the bath, and a function of reheating the bath.
By sharing the stable boiling function of the hot water storage tank, we have achieved a solar hot water supply system that is extremely easy to use and can eliminate the drawbacks of the conventional system.

[Brief explanation of the drawing]

Fig. 1 is a schematic sectional view showing a conventional example, Fig. 2 is a schematic sectional view showing an exhaust heat recovery state in an embodiment of the present invention, and Fig. 3 is a schematic sectional view showing a bath reheating state in this embodiment. , FIG. 4 is a schematic sectional view showing a hot water storage tank boiling state in an embodiment of the present invention. 13...Hot water tank, 17...Heat exchanger, 18...Solar heat collector, 19...Circulation pump, 21...Heat medium heating device, 22...Three-way valve, 23...Return pipe, 28...Heat exchanger, 30...Bypass path, 31 ...Connecting pipe, 32
...Natural circulation heat exchange device, 33...Connection pipe, 37...
Heat medium flow, 38, 38'...natural circulation flow.

Claims (1)

[Claims] 1. A circulation pump for forcibly circulating the heat medium in the solar heat collector to the heat exchanger in the hot water storage tank is provided, and a heat medium heating device and a three-way valve are installed in the middle of the return pipe from the solar heat collector to the heat exchanger in the hot water storage tank. are arranged in series in this order, and a bypass path is formed via the three-way valve to a return pipe between the three-way valve and the heat exchanger in the hot water storage tank, and a bathtub hot water supply is provided in the middle of the bypass path. A solar water heating system equipped with a natural circulation heat exchange device.