JPS58117996A - Waste heat recovery device - Google Patents

Abstract

PURPOSE:To enable waste heat recovery to be made effectively on an waste heat recovery system adapted to recover the heat quantitity of the hot water overflowing from a bathtub into a hot water storage type hot water supplying equipment by a construction wherein an overflow pipe provided in the bathtub is connected to an waste heat recovery means of the hot water supplying equipment. CONSTITUTION:When hot water is supplied into a bathtub 2, a tap 4 is opened to flow the hot water in a hot water storage type hot water supplying equipment into the bathtub. At that time, water is supplied through the lower part of a hot water tank 5, and so the temperature in the lower part becomes lower. If the hot water level in the bathtub exceeds that of an upper opening 11 of an overflow pipe 8, the overflowed hot water is supplied through a hot water supply pipe into an waste heat recovery means 3 having an internal heat exchanger 7 where it is allowed to exchange heat with the low temperature water in the lower part of the hot water storage tank and then guided through a drain pipe 10 into a sewage hole 14. The water which has been heated by the heat exchanger 7 returns into the hot water storage tank 5 by natural convection. Further, in case overflow occurs due to added hot water, heat recovery is made in the same manner. In case of draining of the hot water in the bathtub, heat recovery can be made by opening a drain valve 15 of the overflow pipe 8.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a waste heat recovery system that incorporates a heat exchanger that recovers heat from hot water that overflows when it is poured into a bathtub from a hot water storage type water heater.

Conventionally, a hot water storage type bath water supply system equipped with a waste heat recovery device was as shown in Fig. 3.

In FIG. 3, 1 is a hot water storage type water heater, 2 is a bathtub, and 3 is a waste heat recovery device. High-temperature hot water from a hot water storage type water heater 1 that uses gas, oil, etc. as fuel is forced into a bathtub 2 through a drain 4.

If the temperature in the bathtub is below the extremely high temperature of about 43° C., the user must add hot water to raise the temperature in the bathtub. After the whole family has taken a bath, waste heat is recovered to the hot water storage tank 5 of the hot water storage type water heater 1. In the waste heat recovery circuit, low-temperature water is transferred to the heat exchanger 7 in the waste heat recovery device from the lower part of the hot water storage tank 6 by Bonpro, exchanged with hot water in the bathtub, and then returned to the hot water storage tank 6 again.

In the conventional bath water supply system as described above, first of all, the heat contained in the overflowing hot water is completely wasted when the bath is poured, which is the biggest drawback of the drop-in bath. In addition, the user may leave the area when pouring hot water into the cloth for the first time, resulting in more hot water than necessary (more than the overflow limit when the user takes a bath) and throwing it away. There were many cases. In this case too, heat was wasted. Furthermore, although waste heat recovery is possible, the waste heat recovery device must be located close to the bathtub, so there is a drawback that extra space is required in the bathroom for waste heat recovery. Furthermore, in order to recover waste heat, the pump 6 must be operated, which creates a contradiction in that electric energy is further consumed. In addition, this method requires a control circuit, a remote control box, etc. to operate the pump, so the manufacturing cost including the pump is extremely high, and even when it is actually used, the cost can be amortized by recovering waste heat. It also had the disadvantage of requiring a long period of time.

The present invention recovers the heat of hot water that overflows when the hot water is inserted into the bathtub or when pouring hot water, and simplifies waste heat recovery when supplying hot water to a bathtub using a hot water storage type water heater.
The purpose is to reduce manufacturing costs and shorten the cost amortization period for users.

In order to achieve the above object, the present invention provides a small-capacity container separate from the hot water storage tank of a hot water storage type water heater, and a heat exchanger connected to the hot water storage tank is installed inside to serve as a waste heat recovery device. Hot water is guided from an overflow pipe installed in the tank to this waste heat recovery device by gravity, without using any mechanical means such as a pump, and exchanges heat with the low-temperature water at the bottom of the hot water storage tank.

An embodiment of the present invention is shown in FIG. In FIG. 1, the same numbers as mentioned above indicate the same members. A hot water storage tank 5 and a waste heat recovery device are placed in close proximity to each other, and a heat exchanger 7 is connected to the hot water storage tank 6. A hot water supply pipe 9 is connected to the waste heat recovery device through an overflow pipe 8 provided inside the bathtub, and a drain pipe 1o is connected to a sewage hole. The overall level is that the bathtub and the hot water storage tank are at approximately the same level, and the waste heat recovery device is located on the same level as the bathtub, or below the normal liquid level of the bathtub and above the drain hole. After adopting such a configuration, first, when pouring hot water into the bathtub 2, when the drain 4 is opened, high temperature hot water is dispensed from the hot water storage type water heater 1 (in this case, an electric water heater). Water is supplied to the hot water tank from the water supply port and pushes up the high temperature water inside like a piston, so the lower part of the hot water storage tank is filled with low temperature water. When the water level in the bathtub exceeds the upper opening 11 of the overflow pipe 8, it is guided to the waste heat recovery device 3 by a hot water supply pipe communicating with the overflow pipe 8. The heat exchanger 7 inside the waste heat recovery device re-enters the hot water storage tank 6 from the inlet vibrator 12 at the bottom of the hot water storage tank, and the water at a lower temperature through the outlet vibrator 13. Since natural convection occurs in this path, no mechanical means such as a pump is required. The water, which has become low temperature through heat transfer in the heat exchanger 7, is led to the sewage hole 14 through the drain pipe 1o. A similar process is also used to recover heat from overflowing hot water.

Furthermore, when all the hot water in the bathtub is to be discarded after bathing, by opening the drain valve 16 of the overflow pipe, the hot water is led to the waste heat recovery device 3, and similar heat recovery is performed.

According to the hot water supply waste heat system as in this embodiment, (1) heat can be automatically recovered from the hot water overflowing from the bathtub, resulting in energy savings.

(2) Heat can be recovered from all the hot water in the bathtub by opening the drain valve of the overflow pipe.

(3) Since there is no need to incorporate a waste heat recovery device inside the bathroom, the bathroom can be used more widely.

(4) Since a pump or the like is not used for heat recovery, the manufacturing cost is low and the cost amortization period for the user is short. It also does not consume unnecessary electrical energy.

It has many effects such as

Further, FIG. 2 shows another embodiment of the overflow pipe 8. As shown in FIG.

In the figure, a float 16 is connected to an overflow valve 17 by a chain inside an overflow pipe 8. When the liquid level in the bathtub 1 stops due to pouring hot water or the like, the float 16 pulls the overflow valve 1 to allow hot water to flow. Hot water flows through the lower opening 18. According to this overflow pipe, the hot water to be overflowed is supplied from the lower part of the bathtub, so the temperature is lower than that of the hot water in the upper part. Therefore, the amount of hot water required is small and efficiency is high.

Moreover, since this operation is automatically performed by the float 16, it is possible to drain relatively low-temperature hot water even if the drain valve 15 is opened every time hot water is poured.

As described above, according to the present invention, (1) Waste heat can be recovered from both the overflowing hot water and the entire amount of hot water in the bathtub after bathing, resulting in energy savings.

(2) The waste heat recovery device can be separated from the bathtub, making it possible to use more space in the bathroom.

(3) The manufacturing cost of the waste heat recovery tank is low because no mechanical means such as a pump is used. It also does not consume unnecessary electrical energy.

It has the following effects.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of a waste heat recovery device according to an embodiment of the present invention, Fig. 2 is a sectional view showing another embodiment of an overflow pipe in the waste heat recovery device of the present invention, and Fig. 3 is a diagram showing a conventional waste heat recovery device. FIG. 2 is a configuration diagram of a hot water storage type bath water supply device equipped with a heat recovery device. 1... Hot water storage type water heater, 2... Bathtub, 3
...Waste heat recovery device, 6...Hot water storage tank, 7.
... Heat exchanger, 8 ... Overflow pipe,
9... Hot water pipe, 10... Drain pipe, 14
・・・・・・Sewage hole.

Claims (3)

[Claims] (1) It has a hot water storage type water heater and a heat exchanger inside which is connected to the hot water tank of the hot water storage type water heater, and is further equipped with a hot water supply pipe and a drain pipe that are connected through an overflow pipe installed in the bathtub. A waste heat recovery device consisting of a waste heat recovery device. (2) The waste heat recovery device according to claim 1, wherein a valve is provided at the bottom of the overflow pipe. (3) The waste heat recovery device according to claim 1 or 2, which has a float in the overflow pipe and a valve connected to the float.