JPS58178131A - Heat storage device of water heater using waste heat - Google Patents

Abstract

PURPOSE:To enable recovery of heat which heterofore has been discharged into atmospheric air by providing a heat storage tank, and automatically storing hot water in the heat storage tank at a point in time of generating hot water to store hot water up to a point in time of using hot water. CONSTITUTION:Water within a heat exchanger 4 is heated by surplus heat of a governor 2 through a heat transfer surface of a water cooling wall. When the temperature of hot water increases and the temperature of hot water rises up to a preset temperature of a temperature regulating meter 6 for detecting the temperature of hot water, the contact of the temperature regulating meter 6 is connected, an electrically driven pump 7 is started, hot water within the heat exchanger 4 is sent to a hot water storage tank 10, and water in the same quantity is supplied from a water supply tank 5 to the heat exchanger 4 via a water supply pipe 11. Hence, heat which heretofore has been discharged into the atmospheric air can be recovered.

Description

[Detailed description of the invention] Energy conservation is one of the most important social issues these days.

Among various energy saving measures, recovery of exhaust heat is the most powerful and effective means.

There are various methods of recovering exhaust heat, but the method of recovering heat as hot water is easy and has a wide range of uses.

Many businesses charge membership fees for hot water obtained through waste heat recovery, but there is a time lag between the time the waste heat is recovered, that is, the time the hot water is generated and the time it is used, so even if the waste heat is recovered as hot water, the hot water will not be used. In most cases, they are not fully utilized.

Even if exhaust heat is recovered under such conditions, a large amount of hot water will be discarded or evaporated, which will only result in wasted water.

There are many industries that emit large amounts of high-temperature or high-calorie milling waste gas, and food processing industries such as kitchens are among the industries that use large amounts of medium-hot water.

In the food processing industry, the thermal efficiency is generally 50 to 5 when food is heated and processed using heat from gas, etc. using residual steel, pots, etc.
The thermal efficiency is about 0%, which is very low compared to the 80-90% thermal efficiency of boilers, etc. Also, in the kitchen, a large amount of hot water is required for washing dishes, tea, soup, etc., but currently a large amount of waste heat is recovered as hot water. However, there are few examples where hot water is fully utilized.

The reason for this is that there is a time difference between the time when hot water is generated by the above-mentioned exhaust heat recovery and the time when the hot water is used, so the amount of heat that can be effectively used is small.

In order to overcome the above-mentioned current situation, a heat storage tank was introduced, and when heat is generated, that is, when hot water is generated, it is automatically stored in the heat storage tank, and it is stored until the point of use in drought, and it is the same as in history. The aim is to develop a heat storage device that stores hot water at a constant temperature as much as possible in order to store a larger amount of heat in its volume and expand the range of hot water use.

If we can develop a device that can achieve this purpose, it will be possible to recover as much of the significant heat that was conventionally emitted into the atmosphere and make effective use of the recovered heat, which will become one of the most powerful energy-saving measures. .

In order to meet the above objectives, the present invention provides a heat exchanger for water boiling that recovers waste heat from a combustion machine, such as the combustion chamber or exhaust pipe of a combustion machine that heats and processes food using salmonids in the form of gas or liquid. A hot water storage tank with an air vent pipe with one end open to the atmosphere and hot water supply pipes to various locations is installed at a position higher than the heat exchanger, and a water supply tank is equipped with a water supply device that automatically fills in water when the water level drops. A waste heat water heater with a separate water tank is equipped with a temperature controller that detects the water temperature in the heat exchanger, and when the water temperature rises above the set value of the temperature controller, the water tank is automatically removed. Water is sent to the hot water tank through the heat exchanger, and when the water temperature drops below the set value, the water supply is automatically stopped, and when the water level in the hot water tank reaches the allowable upper limit, the temperature control needle is set. A wastewater plant equipped with piping using solenoid valves, electric valves, electric pumps, etc., so as to stop water supply regardless of the value, and an automatic control circuit that appropriately operates the solenoid valves, electric valves, m-excitation bongs, etc. It adopts the configuration of a heat storage device for a heat-utilizing water heater.

Embodiments of the present invention will be described below.

FIG. 1 is a system diagram of the first embodiment of the present invention, in which some of the equipment is shown in cross section, and arrows indicate the direction in which water flows.

A water supply float valve 5' is installed in a heat exchanger 4, commonly known as a dope, which is equipped with a water-cooled wall heat transfer surface 3 to surround a furnace in which a pot 1 is heated with a gas burner 2. water is heated.

When the water temperature in the heat exchanger 4 rises to the set temperature of the temperature x moderator 6 that detects the temperature of the hot water (approximately 80°C would be appropriate), the temperature controller 6 contacts, the electric cylinder 1 starts, and the hot water in the heat exchanger 4 is sent to the storage m5io through the check valve 8 and piping 9, and the same amount of water is sent from the water tank 5 to the water supply pipe 11. The water is supplied to the heat exchanger 4 through the water.

When an appropriate amount of cold water is supplied in this way, the temperature of the hot water in the heat exchanger 4 begins to drop, the contact point of the temperature vjj node 6 opens, and the electric pump T stops, supplying water to the hot water tank 10 and water supply from the water tank 5. stops.

Reference numeral 13 is an air vent pipe whose one end is open to the atmosphere.

When the gas burner 2 burns and the amount of water supplied from the hot water supply 1 #12 is small, the water level in the hot water storage tank 10 gradually rises to the installation level of the overflow pipe 14.
The hotter water flows out and returns to the heat exchanger 4. In this state, when the hot water supply from the hot water supply pipe 12 is stopped, the amount of water in the heat exchanger 4 does not decrease, so the water supply from the water tank 5 is stopped.

At this time, the temperature of the hot water rises regardless of the set value of the temperature controller 6 until the combustion of the burner 2 stops or the temperature of the hot water supply pipe 120 increases, but it is safe because of the air vent pipe 13.

The check valve 8 is provided to prevent the hot water in the hot water tank 10 from flowing back into the water supply 11#5 due to head difference when the electric pump 1 stops.

During normal operation, the hot water in the hot water tank 10 is kept at a nearly constant temperature close to the set value of the temperature controller 6, but the water level is constantly fluctuating.

If the amount of heat on the user side increases beyond the amount of heat generated, the water level will drop, and in the opposite case, the water level will rise.In other words, fluctuations in thermoelectricity on the generating side and fluctuations in heat on the load side are caused by fluctuations in the water level in the hot water storage tank. It can be absorbed automatically.

The above is an explanation of the first embodiment shown in FIG. 1. FIG. 2 is a system diagram of the second embodiment of the present invention, and shows a part of the equipment in cross section, similar to FIG. 1.

The combustion waste gas that heated the pot 1 with the gas burner 2 flows out of the furnace from the chimney 15, and heats the water inside through the smoke tube-shaped heat transfer surface 3 of the heat exchanger 4 installed in the middle of the chimney 15. It is then released into the atmosphere.

The heights of the storage #I41th110 and the water supply ia5 are set so that the normal water level of the water supply tank 5 and the maximum permissible water level shown by the fruit 116 of the hot water storage tank 10 are 4-.

When the gas burner 2 burns, the water temperature in the heat exchanger 4 rises, and the contact point of the temperature controller 6 is turned on, the solenoid valve 1T installed in the middle of the water supply pipe 11 is energized and opens to increase the water level in the water tank 5 and the hot water storage tank 10.
Due to the difference in water level from the water level, water is supplied from the water tank 5 to the heat exchanger 4 from the water supply pipe 11 via the solenoid valve 1T, and the same amount of hot water is distributed to the heat exchanger 4.
It flows into the storage tank 10 through the water so as to be pushed up.

At this time, the water level in the water supply tank 5 is low) and the float is lowered to the float valve 5'.
is opened and water is supplied to the water supply jVI5.

In this way, if the amount of hot water flowing into the hot water storage tank 10 is greater than the amount flowing out from the hot water supply -f112, the water level in the hot water storage tank 10 will rise, but when it rises to the allowable upper limit water level 16 shown by the dotted line, it will be the same as the water level of the water supply 4115. As the height increases, there is no drop and the temperature-tube needle 6 contacts, and even though the solenoid valve 17 is open, the water supply from the water tank 5 to the heat exchanger 4 or to the hot water tank 10 is stopped, and the heat exchange Inside vessel 4 and hot water tank 1
The water temperature inside the tank will rise further, but since there is an air vent pipe 13, it is safe to release the tank.

If the gas burner 2 is stopped for some reason, the water temperature in the heat exchanger 4 decreases and when it becomes below the set value of the temperature controller 6, the solenoid valve 17 closes and the water supply is stopped.

At this time, even if hot water is being used at the hot water consumption faucet, the water level in the hot water storage tank 10 only decreases, and the temperature of the hot water is usually approximately constant, around the set value of the temperature controller.

FIG. 5 is a system diagram showing an aspect of a sixth embodiment of the present invention.

A heat exchanger 4 having a heat transfer surface 3 made of a coiled water tube is provided in the exhaust chimney 15 of the combustion machine, an electric pump 7 is constantly operated, and water is supplied from the electric pump 7 through the coiled heat transfer surface 3. It is heated by the combustion exhaust gas in the heat exchanger 4 and is pumped to the small hot water tank 18.

When the hot water temperature is lower than the set value of the temperature controller 6 that keeps the temperature of the hot water in the small water tank 18 constant, the electric circuit is set so that the solenoid valve 1T closes 17' by contact operation. .

Therefore, as shown by the arrow, when the water temperature in the small hot water tank 18 is low, the hot water in the small hot water tank 18 is sucked into the electric pump T, passes through the solenoid valve 17' in the piping 19, and is heated again through the electric pump T. Small hot water tank 18 sent to exchange v54
Return to The temperature of the hot water gradually rises while performing the above-mentioned forced circulation operation, and when the water temperature rises above the set temperature of the temperature controller 6, the contact of the temperature controller 6 operates, the solenoid valve 17' closes, and the KM valve 1T opens. Cold water is drawn into the pump T from the water supply tank 5 through the solenoid valve 11, and is supplied with small warm water from the heat exchanger 4.
Enter ri18.

Since the conventional forced circulation piping 19 to the electric pump r is closed by closing the electromagnetic valve 17', the hot water that has entered the small drought tank is forced to be sent to the hot water storage tank 10 through the piping 9.

Pump 7 because cold water entered or the combustion machine stopped, etc.
Heat exchange 04. Small hot water tank 18. Piping 19. Solenoid valve 1r
', *The dynamic pump 7 and hot water are forcibly circulated.

When the amount of hot water used in the hot water supply pipe 12 and the cock 1f is low, the water level in the hot water storage tank 10 rises, and when it reaches the allowable upper limit water level 16, the hot water returns to the inlet side of the electric pump T through the overflow pipe 14. The water temperature in the tank 18 is higher than the set temperature of the temperature v4 node #t6, and the drought side 12,1
If hot water is not being used in step 1, electric pump T will be activated.

Heat exchanger4. Small hot water tank 18. Piping 9. Overflow pipe 14. Solenoid valve 17. Although the temperature rises during circulation with the electric pump T, the air vent pipe 13 prevents the risk of steam pressure rising and is safe.

Figure 8g4 is a system diagram of the fourth embodiment of the present invention.

The fourth embodiment is almost the same as the second embodiment, but is an embodiment in which a plurality of heat exchangers are used, with one each for the hot water storage [10] and the water supply tank 5.

Each heat exchanger 4-1.4-2.4-5 is installed in a chimney 15-1-15-3 of a separate combustion machine, and when the water temperature in each heat exchanger rises, the heat exchanger The temperature controllers 6-1, 6-2, and 6-5 operate to maintain a constant water temperature in the corresponding electromagnetic valves 17-1.

17-2, 17-3 open, and the water level and storage # of the water tank 5 are opened.
Water is supplied from the water supply pipe 11 to the heat exchanger through the electromagnetic valve due to the difference in water level from the water level in the tank 10, and is then sent from the heat exchanger to the hot water storage tank 10 through the pipe 9.

If the set temperatures of the respective temperature controllers are set to be substantially the same, the water temperature in the hot water storage tank 10 will be substantially constant.

Next, the effects of the present invention will be described.

r7iAs stated above, the functions required of the device of the present invention are:
It automatically stores hot water at the highest temperature possible, automatically supplies the required amount of hot water to the required location, and also has the function of keeping the water temperature in the hot water tank almost constant regardless of the volume and time of supply. It is what you need.

This objective is achieved in all of the first to fourth embodiments when the water level in the hot water storage tank is between the upper and lower eye regions.

Therefore, if the internal volume of the hot water storage tank is set to an amount sufficient to compensate for fluctuations in the heat generation side or fluctuations in the heat supply side, the water temperature can be kept almost constant.

How should the internal volume be determined? Unless the internal volume can be determined quantitatively, it is difficult to embody the device of the present invention.

Therefore, we will assume a general example in a kitchen, clarify the variation of the heat storage amount or hot water storage amount according to the assumed example, and describe a method for calculating the required minimum volume of the hot water storage tank in this assumed example.

If the volume of the hot water storage tank is too small, when the amount of heat on the generation side is large, the water level in the storage 1MI411 will often rise to the upper limit of the eave valley, causing the set value of the temperature-tube needle to rise, causing the water temperature to rise and boiling.
This not only wastes heat but also wastes water, and when the amount of heat on the supply side is large, the hot water storage tank often becomes empty and becomes unusable.

Furthermore, if the internal volume is increased more than necessary, not only will the equipment cost increase, but the amount of heat dissipated will also increase, resulting in heat loss.

Figure 5 is a graph showing the change in heat amount between the heat generation side and the heat supply side in a hypothetical example.The specific example shown in the graph is a ramen or Japanese soba restaurant with a maximum combustion rate of 30,000 kcal per hour (lower calorific value standard). It is assumed that a gas stove for boiling noodles is used, and that the amount of heat transferred to the pot for boiling noodles is 40%, and the remaining 60% of the combustion heat is exhausted from the chimney.

In this hypothetical example, it is assumed that half of the exhaust heat, that is, 60% of the combustion gate, is recovered by the device of the present invention, and the integrated thermal efficiency is improved to 70%.

Therefore, the maximum heat amount of the vertical axis is 30% of 30,000 kilocalories, or 9,000 kilocalories per hour, as shown in Figure 5.

The horizontal axis shows the time from 11 am to 6 am, and the dotted line shows the amount of heat generated (recovered heat) every 15 minutes during this time, and at the same time shows the change in the amount of heat on the supply side (user side) during that time. It is shown in a bar graph form with a solid line.

The diagonal line indicates the amount of decrease in heat in the 1MI storage tank, and the crossing line indicates the amount of increase in heat into the hot water storage tank, that is, the amount of increase in the amount of heat storage. This will be explained in chronological order below.

At 11 o'clock at the beginning of the graph, the store has not yet opened, and it is time to prepare for opening.

During this period, the gas stove for boiling noodles is used in relatively large amounts to boil the water in the pot, and from 11:00 to 11:15, the average speed is 680 per hour, as shown in the dotted bar graph.
It is operated in such a way that only 0 kilocalories of heat is given to the heat exchanger.

- On the supply side of the men's bath, a large amount of hot water is required to prepare for opening, prepare soup and tea, and clean the store, and as shown by the solid line in the graph, an average of a000 kilocalories is used per hour.

Therefore, during this time, 6.800 kcal of heat flows into the storage unit from the heat exchanger per hour, and 8.00 kcal of heat flows into the storage unit per hour.
Since 0 kilocalories of heat flowed out to the supply side, the amount of heat stored in the hot water storage tank decreased by the difference in heat amount of 1200 kilocalories per hour. The actual amount of heat stored is 300, which is one quarter of 1200 kilocalories, even though the reduction time is 15 minutes.
This results in a decrease in kilocalories.

As preparations for the store's opening progress, the amount of gas used on the gas stove for boiled noodles and the amount of hot water used on the supply side will also decrease, but as shown in the graph, customers begin arriving at 11:45 and the gas stove for boiled noodles will be closed until 1:15. The amount of use of the men's bath is relatively small because the store is busy and food washing is not done.

Therefore, from 11:45 to 13:15, the heat storage t in the hot water storage tank increases as shown by the cross line.

After 3:15 p.m., each gas starts to decrease, so the amount of gas used decreases and the amount of heat transferred to the hot water tank decreases, but on the hot water side, the amount of tableware that was left unattended during busy hours decreases. As cleaning is performed, the amount of hot water used increases rapidly.

Therefore, as shown by the first line, the amount of heat stored in the hot water tank decreases.

Even during such a busy period, the heat ends at 2:00 p.m. After that, the amount of heat decreases on both the heat generation side and the heat supply side, and the amount of heat stored in the hot water storage tank repeats small increases and decreases until it reaches 15:00.

As mentioned above, the amount of heat in the hot water storage tank increases and decreases while absorbing fluctuations in the amount of heat generated and the amount of heat used.

A diagram showing this operation in detail is the graph in Figure 6. Similar to the graph in Figure 5, the vertical axis shows the heat amount, and the horizontal axis shows the change in the heat amount in the storage tank using a line graph. .

The amount of stored heat was 2,000 kcal at 11:00, but it decreased slightly until 11:45, then increased and reached 8 at 15:15.
It reaches a maximum of 100 kcal and decreases until 2:00 pm, after which it increases and decreases slightly until 15:00, reaching 1 calorie of 5,200 kcal.

The above change in the amount of heat storage is actually a change in the amount of hot water in the hot water storage tank, so the change in the amount of heat storage is calculated by assuming that the supply water temperature is 20°C and the hot water temperature is 80°C. The amount of water shown on the right vertical axis is what is replaced with .

The amount of hot water stored was 66 liters at 11:00, but at 1:15 p.m. it reached a peak of 165 liters, and by 3:00 p.m., the amount of hot water stored was approximately 87 liters.

The minimum effective hot water storage tomb for which the fluctuations shown in Figure 6 can be expressed as a series is 110 liters, which is the maximum of 135 liters at 16:15 and the minimum of 25 liters at 11:45.

In reality, if you install a hot water tank with an effective internal volume of 150 liters and a total internal volume of about 160 liters, the hot water in the tank will not rise to a boil or run out, and the heat that would have been left in the atmosphere will be absorbed. As mentioned above, if you measure the heat usage of the store according to the above items, you will be able to use it effectively and save money! The volume of 6N can be determined. The outline of the heat balance in the hypothetical example is that the heat balance between 11 a.m. and 3 p.m.
Burning 1,500 kilocalories of gas gives 600 kilocalories of heat to a pot for boiling noodles, recovers 21,450 kilocalories of heat from the exhaust gas using a heat exchanger, and exhausts the same amount of heat into the atmosphere through the chimney. Within this time,
18.250 kcal was used, and the amount of heat storage increased by 3200 kcal.

If it is used for a bath in a lagoon with a temperature of 80°C and 871 J meters after 3:00 p.m., 260 liters of 40°C hot water can be produced, which is almost enough for a general household bath, so the entire amount of hot water in the storage tank is effective. It is possible to use it for

The field in which the present invention can be used is not only the restaurant industry, but also the waste heat from school lunch kitchen machines, which can be used in school grounds for weeding purposes, and the waste heat from factory cafeterias, where waste heat can be recovered and used for baths. It has a wide range of applications, and can also be effectively used in other areas such as mountain, fish processing plants, and instant ramen manufacturing plants.

Other combustion equipment that can recover waste heat using the heat exchanger of the present invention include various ovens, various fryers, various types of food dryers, and roasting machines. As described above, the number of devices that require membership fees for the apparatus of the present invention is enormous, and the amount of heat that can be recovered is also enormous, so a large energy saving effect can be expected.

It should be noted that the present invention is not limited to the above-mentioned embodiments, but can be modified in various ways within the scope of its purpose. For example, (11) Use a water pressure reducing valve that automatically opens when the outlet side pressure of the valve used for hot water boilers, etc. drops to supply water instead of the water tank and float valve.

(2) Detect the false upper limit water level of the hot water storage tank using an electrode type or float type water level detector instead of the overflow pipe, and stop the electric valve or electric pump to prevent the water level in the hot water storage tank from rising too high. case.

(3) Detect the lower limit water level of the hot water storage tank using an electric or float type water level detector, and use a wake-up valve or 'f1. Start the sea bream pump to prevent the heat exchanger from running dry.

(4) a water-cooled wall heat transfer surface that prevents heat radiation from the combustion chamber of the first embodiment; A heat exchanger having a heat transfer surface provided in the exhaust pipe of the third embodiment is used.

(5) Instead of using two solenoid valves in the sixth embodiment, one three-way solenoid valve is used.

FIG. 5 is a graph showing the temporal change in the amount of heat on the heat generation side and the heat supply side, and 6th +N is a graph showing the temporal change in the amount of heat stored in the hot water storage tank.

1... Pot, 2... Gas burner, 3... Water cooling wall or heat transfer surface, 4... Heat exchanger, 5... Water tank, 5'...
・Float valve, 6... Temperature controller, 7... Electric pump,
8... Check valve, 10... Hot water storage tank, 11... Water supply pipe, 12... Hot water supply pipe, 13... Air vent pipe, 14.
...Overflow pipe, 15...Chimney, 16...Maximum allowable water level, 1T...! LLm valve, 18...Small hot water tank.

that's all 3rd figure f4 diagram To XIO thing time Spear 6 sword

Claims (4)

[Claims] (1) A heat exchanger for boiling water is installed in the combustion chamber or exhaust pipe of a sintering oven that heats and processes foods using fuel such as gas or liquid, to recover the waste heat of the clam broiling machine. A storage tank with an air vent pipe with one end open to the atmosphere and hot water pipes to various locations is installed at a higher position than the heat exchanger, and a separate water tank is equipped with a water supply device that automatically fills with water when the water level drops. In a water heater using waste heat installed in When the water temperature drops below the set value, the water supply is automatically stopped, and when the water level in the hot water tank reaches the permissible upper limit, regardless of the temperature control needle set value. Solenoid valve to stop water supply. A heat storage device for a water heater using waste heat, comprising piping using an electric valve, an electric pump, etc., and an automatic control circuit for appropriately operating the solenoid valve, electric valve, electric pump, etc. (2) A water supply tank is provided with a water supply valve that automatically opens and water is supplied when the float is lowered, and a hot water storage tank equipped with an air vent pipe and a hot water supply pipe is provided at a position higher than the heat exchanger. Pipes are installed between the water supply tank and the heat exchanger, and between the heat exchanger and the hot water storage type, and when the water temperature in the heat exchanger rises above the set value of the humidity controller that detects the water temperature, it automatically starts and sets the temperature. An electric bonder that is electrically controlled to automatically stop when the water temperature drops below the specified value is installed in either the piping between the water tank and the heat exchanger or between the heat exchanger and the hot water storage catcher, and the electric bonder 2. A heat storage device for a water heater utilizing waste heat according to claim 1, further comprising a check valve in series with the water storage tank and an overflow pipe between the allowable upper limit water level of the hot water storage tank and the heat exchanger. (3) A water supply tank equipped with a water supply valve that automatically opens and supplies water when the float is lowered is installed at a higher position than the heat exchanger, and a friendly hot water tank equipped with an air vent pipe and a hot water supply pipe is installed in the hot water storage tank. The upper limit of water level in the heat exchanger is installed at the same height as the normal water level in the water tank, and piping is installed between the water tank and the heat exchanger, and between the heat exchanger and the hot water tank, so that the water temperature in the heat exchanger is the same as the water temperature. It automatically opens when the temperature rises above the set value of the temperature controller that detects the temperature.
Install an electrically controlled solenoid valve or electric valve in the piping between the water tank and the heat exchanger or between the heat exchanger and the hot water storage tank, which is electrically controlled to close automatically when the water temperature drops below a set value. A heat storage device for a water heater using waste heat as set forth in claim 1, which is provided in a water heater using waste heat. (4) A heat exchanger for waste heat recovery water heaters that recovers exhaust heat from combustion machines for kitchens, etc. to heat water, and the water in the heat exchanger is forcibly circulated using an electric pump. A water supply pipe is installed that connects the electric bong suction part of the forced water circulation heat exchanger to a water tank equipped with a water supply valve that automatically opens when the float is lowered to supply water, and a hot water storage tank equipped with an air vent pipe is installed. , a hot water pipe is provided at a higher position than the heat exchanger and the water supply tank, and connects the hot water storage tank and the electric bong discharge part or the heat exchanger outlet part, and one is installed in each of the water circulation path and the water supply pipe. A solenoid valve or a motorized valve is installed, and a temperature controller that detects the water temperature in the heat exchanger opens the solenoid valve or motorized valve in the temperature controller when the water temperature drops below the set value. A water heater using waste heat according to claim 1, which is provided with an automatic control circuit 1 in which an electric valve performs reverse opening and closing operations, and further provided with an overflow pipe that connects the allowable upper limit water level of the hot water storage tank and the water supply pipe. Heat storage device &.