JPS58124195A - Method for recovering thermal energy by heat exchange - Google Patents

Abstract

PURPOSE:To enable to enhance heat-exchanging efficiency, by a method wherein a heat exchanger is floated up to a position in proximity to the surface of hot water in a storing tank and is brought into heat exchange with water fed into the tank, in recovering thermal energy from residual hot water contained in a bathtub or the like. CONSTITUTION:Water is poured into a hot water storing tank 2, while an appropriate quantity of hot water such as residual hot water is poured into the storing tank 1, in which the heat exchanger 3 is floated up to a position in proximity to the surface of hot water by a float 4. When the hot water temperature at the surface level is higher than the water temperature at a bottom part of the tank 2, a water-feeding pump 8 is operated to feed the water at the bottom part of the tank 2 into the heat exchanger 3, thereby bringing the water into heat exchange with hot water. In this case, since the heat exchanger 3 is located in proximity to the surface of hot water which is on the high-temperature side, heat is exchanged at the maximum efficiency. When the temperatures of hot water and water are equalized, the pump 8 is stopped to finish the heat exchange. Accordingly, even thermal energy at a relatively low level and intermittent thermal energy can be recovered efficiently.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for collecting the thermal energy contained in hot water by heat exchange.

In recent years, attempts have been made to collect solar radiant heat, wind energy, and the like as thermal energy. this is,
The aim is to reduce fuel consumption by substituting a portion of this thermal energy for fuel, thereby reducing fuel costs. There has been a growing momentum to try to capture the thermal energy contained in things that have been abandoned in the past, and to make effective use of energy.

By the way, this energy is collected as energy to heat new water, but the heat source targeted for energy collection has a relatively high temperature and is continuously supplied, so it is small ( Both species are limited to flies that can heat water up to several tens of degrees.For example, even if the temperature is high in hot water, it does not cover those that are discharged intermittently or all at once; Even if it is discharged, relatively low temperature water below 50 degrees Celsius was not targeted. However, even hot water with a temperature of about 40 degrees Celsius, such as leftover hot water from a bathtub, 20 in this warm water
Since it contains about kcal/L of usable thermal energy, collecting this thermal energy can further reduce fuel costs, but as mentioned above, conventional thermal energy collection This is done by heating new water to a temperature of several tens of degrees, so it was thought that it would be impossible to extract thermal energy from a heat source with a lower temperature. Since there was no way to effectively collect thermal energy from the water that was discharged and the amount of discharge was not constant, this type of hot water was simply discarded without being used in any way. However, if this hot water can be heat-exchanged with water at 15 to 20°C and 1 ton of thermal energy can be collected, the collection rate of thermal energy for hot water will be 40 to 50%. If the new water is used as bathing water, it is sufficient to heat the bathing water to about 40 to 50 degrees Celsius, resulting in a fuel cost savings of about 20 to 30%.

The present invention has been made in view of the above-mentioned points, and even if the temperature of hot water as a heat source is relatively low, such as leftover hot water in a bath, or its discharge is not continuous,
The thermal energy contained therein can be collected efficiently even if it is intermittent or temporary.

Hereinafter, the present invention will be specifically explained based on the drawings. In the figure, numeral 1 is a storage tank, 2 is a hot water storage tank, and 3 is a heat exchanger.

The storage tank 1 is a tank that temporarily stores hot water discharged from a bathhouse or the like in order to exchange heat with the water filled in the hot water storage flF2, and the discharged hot water is first poured into this storage tank 1. When hot water is to be discharged all at once, such as leftover hot water in a bath, this storage tank 1 must not only have a sufficient volume to store it, but also suppress heat dissipation as much as possible during heat exchange. It goes without saying that the surface area can be reduced within an allowable range, for example.

The heat exchanger 3 is similar to a normal one of this type, and although there are no particular limitations on its structure, it is always located near the liquid level regardless of the amount of hot water poured into the storage tank 1. Therefore, in the storage tank 1, the part with the highest temperature is
It is designed to exchange heat with hot water. The one shown in Figure 1 is one example, and a float 4 is attached to this float so that it floats on the liquid surface. Of course, in this case, the water pipe 5 connected to the heat exchanger 3 is a flexible pipe, and is configured to cope with the raising and lowering of the heat exchanger 3. The heat exchanger 3 shown in FIG. 2 is installed at one point on the inner wall of the storage tank 1 for positioning. The heat exchanger 3 is pivotally mounted. This method has the advantage that when the heat exchange is finished and the hot water in the storage tank 1 is discharged, the heat exchanger 1 does not hang from the hook 12 and fall to the bottom of the tank. The tank cannot start heat exchange unless a certain amount or more of hot water is injected, and the storage tank 1 is equipped with a liquid level adjustment mechanism 14, and the hot water is intermittently or continuously injected. Suitable for heat exchange with a constant liquid level.

It goes without saying that heat exchange is performed only when the temperature of the hot water in the storage tank 1, at least near the liquid level, is higher than the temperature of the water in the hot water storage tank 2. Thermometers 6 and 7 are attached to the bottom of the hot water storage tank 11!2, and these detect the temperature of the hot water near the liquid level of the storage tank 1 and the temperature of the water near the bottom of the hot water storage tank 2, and these are used for heat exchange. When appropriate, the water pump 8 is operated to send water to the heat exchanger 3, thus exchanging heat. Incidentally, the hot water storage tank 2 is similar to that of a normal water heating device of this type,
Although not shown, it goes without saying that a heating device such as a water heater or a solar heat collector is attached.

Although the figure shows an example in which the float 4 is attached to the upper surface of the heat exchanger 3, this system has the following advantages. In other words, because the float 4 covers the liquid surface, less heat is radiated (therefore, the efficiency of using thermal energy is increased).Also, in general, residual hot water in a bathtub, etc., has floating matter with a high fat content that collects near the water surface. Therefore, if the heat exchanger 3 is located on the water surface, these floating objects will adhere to the external heat transfer surface of the heat exchanger and significantly impede heat transfer. 4, the heat exchanger is always located at an appropriate position below the liquid surface, so that contamination by floating matter can be minimized.

Here, a method of exchanging heat between the hot water injected into the storage tank 1 and the water filling the hot water storage tank 2 will be described.

First of all, store hot water! 2 is filled with water, and an appropriate amount of hot water is poured into the storage tank 1. Then, since the heat exchanger 3 floats near the surface of the hot water, it detects the temperature of the hot water nearby and the temperature of the water near the bottom of the hot water storage tank 2, and when the former temperature is higher, the water pump 8 is activated to send the water in the hot water tank 2 to the heat exchanger 3, where it exchanges heat with hot water. As the heat exchange progresses, the temperature of the hot water in the storage tank 1 decreases and the temperature of the water in the hot water tank 2 increases, and when the two become the same, the heat exchange ends. Here, the feature of the present invention is that the heat exchanger 3 is always located near the surface of the hot water.

In other words, as the heat exchange progresses, the temperature of the hot water in the storage tank 1 does not drop uniformly all over, but the water that comes into contact with the heat exchanger cools and settles, so a temperature gradient gradually develops inside the tank. This will occur.

However, since the heat exchanger 3 is always located near the liquid level,
It is always in contact with the warm water that has the highest temperature, and heat exchange occurs most efficiently.

From this point of view, when adding new hot water to hot water that has already undergone heat exchange, either intermittently or continuously, it is important to ensure that this new hot water does not disturb the temperature gradient of the hot water in the tank. At the same time, it is important that the warm water discharged outside the tank has the lowest temperature near the bottom of the tank.

Figure 2 shows an example of such a structure, in which an auxiliary tank 9 is attached to the storage tank 1, and water holes 10 are bored at several locations at different heights between the auxiliary tank 49 and the storage tank 1. The new hot water is once injected into the auxiliary tank 9 and then flows into the storage tank through the water passage hole 10. In this way, new hot water injected into the auxiliary tank 9 enters the tank through the water passage hole 10 located closest to the hot water of the same temperature in the storage tank 1. Of course, in most cases, the temperature of newly added hot water is higher than the warm water near the water surface in the reservoir 11, so this hot water enters the tank through the water passage hole 10a closest to the liquid surface. However, if the temperature of this hot water is the same as or lower than the temperature of the hot water near the bottom of the tank, it will enter through the lowest water passage hole 10a and drain through the drain port 11 without any heat exchange. It passes through the tank and is discharged outside the tank. Incidentally, Figure 3 shows an example in which a porous partition wall 12 is provided in the storage tank 1 instead of the auxiliary tank 9 to partition a part of the storage tank, and new hot water can be added to the inside of this partition. When injected, there is almost no difference in effect from the one described above.

As described in detail above, the present invention is capable of injecting hot water into the storage tank 1 to collect the thermal energy contained in the hot water continuously or all at once by heat exchange. The heat exchanger 3 is installed in the hot water, and since the heat exchanger 3 is always located near the surface of the hot water, it always exchanges heat with the object with the highest temperature. It has high exchange efficiency.

[Brief explanation of the drawing]

Figures 1 to 3 are explanatory diagrams schematically showing one embodiment of the method of the present invention. 1... Storage tank 2... Hot water storage tank 3...
・Heat exchanger 4...Float 5...Water pipe 6...Temperature meter 7...Temperature meter
8... Water pump 9... Auxiliary tank 10.
... Water hole 11 ... Drain hole 12 ... Partition wall 13 ... F
14...Liquid Level Adjustment Mechanism Patent Applicant Hiroshi Ide's Procedural Amendment (Voluntary) 1. Display of the case Patent Application No. 007787 of 1982 2, Title of the invention Method of collecting thermal energy by heat exchange 3, Person making the amendment Relationship to the case Patent applicant 4, Date of amendment order Voluntary amendment 5, Amendment Subject ■ Column for the name of the billboard wheel invention ■ Column for claims in the specification ■ Column 6 for detailed explanation of the invention, contents of amendment ■ Change the title of the invention to “Collection of thermal energy by heat exchange 2”
, Claims A method for collecting thermal energy in which when hot water is injected into a storage tank equipped with a heat exchanger, the heat exchanger number ζ sends water and performs heat exchange between the water and the hot water. In this method, the heat exchanger is floated near the liquid surface of the hot water, and is always in contact with the hot water near the liquid surface, and heat exchange is performed between the heat exchanger and the hot water.Collection of thermal energy by heat exchange Method 3,
In the specification - 2nd page, 5th line, 6th line, 17th line, 19th line, 3rd page, 5th line, 9th line, 10th line, In line 20, page 9, line 19, the words ``supplement'' are corrected to ``collection''.

Claims (1)

[Claims] In this thermal energy collection method, hot water is injected into a storage tank equipped with a heat exchanger, and the water is also sent to the heat exchanger to exchange heat between the water and the hot water. A method for collecting thermal energy by heat exchange, which is characterized by floating the liquid near the liquid surface, constantly bringing it into contact with hot water near the liquid surface, and exchanging heat with this hot water.