JP4560449B2 - Circulating hot water storage system - Google Patents

Description

  The present invention comprises a hot water storage tank for storing hot water, and a circulation line consisting of an outward conduit from the hot water storage tank to the connecting portion of the hot water tap and a return conduit from the connecting portion to the hot water storage tank, Circulating hot water storage system that circulates hot water stored in the hot water storage layer to the circulation pipe and supplies hot water to the hot water tap from the circulation pipe, and particularly applicable to business use such as home use or hotels. The present invention relates to a circulating hot water storage system that can immediately supply hot water stored in a tank to a hot water tap through a circulation pipe.

In a hot water supply system used for home use or the like, usually, when there is a demand for hot water supply, hot water is sent from a water heater or the like to a hot water tap such as a hot water supply valve or a hot water mixing tap through a hot water supply line. Accordingly, when there is no demand for hot water supply, the temperature of the hot water staying in the hot water supply pipe decreases due to heat radiation, and even when the hot water tap is opened, water at a temperature that does not reach the appropriate temperature (for example, 30 ° C.) is released. There was an inconvenience that hot water of appropriate temperature would not come out until the accumulated water in the pipeline was discharged. At the same time, the discharge of the stagnant water wasted water resources and wasted water and sewage charges.
In particular, in business applications such as hotels, since the hot water supply pipeline becomes long, it is desirable to avoid the inconvenience and waste described above.

Therefore, as a hot water storage hot water system that can avoid such inconvenience and waste, as shown in FIG. 5, a hot water storage tank 101 that stores hot water heated by the heat source unit 130, and a hot water tap 105 from the hot water storage tank 101. A circulation pipe 110 consisting of an outgoing pipe 108 leading to the connection section 106 and a return path 109 leading from the connection section 106 to the hot water storage tank 101, and hot water stored in the hot water storage tank 101 to the circulation pipe 110. A circulating hot water storage and hot water supply system 500 that supplies hot water in a form that includes a circulation pump 111 that circulates and supplies hot water circulated in the circulation line 110 to a hot water tap 105 connected to the circulation line 110 is known. (For example, see Patent Documents 1 and 2).
In such a conventional circulating hot water storage and hot water system 500, the temperature of hot water at the upstream side of at least the connecting portion 106 with the hot water tap 105 in the circulation pipe 110 is set to an appropriate hot water temperature (for example, 50 ° C.) or higher. By maintaining the hot water, the hot water having an appropriate temperature or higher can be immediately supplied to the hot water tap 105 through the circulation pipe 110.

On the other hand, in a cogeneration apparatus that uses exhaust heat, all or a part of the obtained heat includes heat recovered from the necessity of cooling a prime mover (including a fuel cell or the like). For example, engine jacket water or fuel cell cooling water may be used. Therefore, depending on the prime mover, the temperature of the cooling water may be regulated below a certain reference temperature, and the hot water storage tank that temporarily stores hot water heated by the exhaust heat of cogeneration using such a prime mover is It is preferable to constitute a temperature stratification type in which hot water is stored in a form in which a temperature stratification is formed with high temperature water and low temperature water at the bottom. That is, the temperature-stratified hot water tank is cooled by the motor and exhaust heat by circulating low temperature water from the bottom, cooling the motor (exhaust heat recovery) and returning the hot water to the upper part. The two purposes of recovery are achieved at the same time.
When hot water of low temperature flows into the upper part of such a temperature stratified hot water tank, the temperature stratification is broken, so the temperature of the hot water discharged from the prime mover is controlled by adjusting the circulation flow rate, etc. Maintained.

JP-A-8-121800 JP-A-8-159501

However, in the above-described conventional circulating hot water storage and hot water system 500 (see FIG. 5), the temperature of the hot water flowing through the forward pipe 108 is maintained at or above the appropriate hot water supply temperature. The hot water returned to the tank 101 was also at a relatively high temperature. Therefore, since it is difficult to create and maintain temperature stratification in the hot water storage tank 101, the hot water storage tank 101 to be used is premised on a complete mixing type rather than a temperature stratification type.
That is, the hot water storage tank is configured as a temperature stratification type, and a circulation pipe is provided as in the above-described conventional circulation-type storage hot water supply system, so that hot water at an appropriate temperature or higher is immediately supplied through the circulation pipe. It was difficult to configure so that it could be supplied to.

  In addition, by connecting the return pipe 109 to a substantially central portion in the vertical direction of the hot water storage tank 101, the hot water storage tank 101 is configured to form a temperature stratification boundary below the connection part 102. It may be configured as a temperature stratification type for storing. However, since hot water stored above the connecting portion 102 of the hot water tank 101 needs to be maintained at a high temperature, the amount of activity of the hot water tank 101 is reduced and the hot water tank 101 is connected through the return pipe 109. In order to maintain the temperature of the hot water flowing into the hot water at a temperature that is hardly different from the temperature of the hot water flowing out from the hot water storage tank 101 to the outgoing line 108, a large flow rate of circulation is required. There was a problem in that the circulation power and heat dissipation loss increased. Moreover, in order to avoid it, it was necessary to increase the diameter of the circulation pipe 110 and to strengthen the heat insulation work, which was a factor in increasing the equipment cost.

  The present invention has been made in view of the above-mentioned problems, and its purpose is to circulate hot water even when the hot water storage tank is configured as a temperature stratification type in order to effectively use the exhaust heat of the cogeneration apparatus, for example. Providing a circulating hot water storage system that can reduce power and heat dissipation loss as much as possible, and can realize immediate hot water supply by circulating hot water in the circulation line to avoid inconvenience and waste caused by waste water There is in point to do.

  In order to achieve the above object, the circulating hot water storage system according to the present invention is applied to a circulating hot water storage system that realizes immediate hot water supply by circulating hot water in a circulation line using a temperature stratified hot water tank. The common means is to reduce the temperature of hot water returning to the hot water tank after circulating through the circulation line until the temperature becomes close to, for example, tap water by the above heat radiating means. Composed.

The circulation type hot water storage and hot water system according to the present invention includes a hot water storage tank for storing hot water, an outgoing line from the hot water storage tank to a connection part of the hot water mixing tap, and a return pipe from the connection part to the hot water storage tank. A circulating hot water storage and hot water system that circulates hot water stored in the hot water storage layer to the circulation conduit and supplies hot water to the hot water mixing tap from the circulation conduit. 1 characteristic structure is comprised in the temperature stratification type | mold which the said hot water storage tank stores hot water supply with the form which forms temperature stratification,
The circulation pipe is connected to the hot water tank in a form in which the hot water flows out from the upper part of the hot water tank to the outgoing pipe and hot water flows into the lower part of the hot water tank from the return pipe. And
Wherein the recovery pipe, Rutotomoni includes a radiator means to promote heat radiation of the hot water,
A water supply pipe for supplying clean water to the lower part of the hot water tank, and a cooling water pipe laid to reach the upper part of the hot water tank from the lower part of the hot water tank via a heat source device to be cooled, The water taken out from the lower part of the hot water storage tank to the cooling water conduit is heated by the heat source unit, and then returned to the upper part of the hot water storage tank.
In a configuration for supplying clean water from the water supply pipe to the hot water mixer tap,
The hot water mixing tap is configured to be capable of discharging the clean water supplied from the water supply pipe separately from the hot water supplied from the outgoing pipe or mixed with the hot water. is there.

According to the first characteristic configuration, the circulation conduit is connected to the hot water storage tank as described above, and the heat radiating means is provided in the return pipe that allows hot water to flow into the lower part of the hot water storage tank. In the hot water storage tank constructed as described above, the temperature of hot water that has flowed out from the upper part of the hot water tank to the outgoing pipe and returned to the return pipe without being supplied to the hot water mixing tap (for example, 60 ° C.) Even if it flows in, it can be lowered to a temperature at which the temperature stratification of the hot water tank is not destroyed.
In addition, when the hot water tank is configured to store hot water heated by a cogeneration device or the like, the temperature of the hot water in the lower part of the hot water tank can be kept relatively low (for example, 25 ° C.). The cogeneration apparatus can be sufficiently cooled by the low-temperature water taken out from the lower part of the hot water tank, and heated hot water can be supplied to the upper part of the hot water tank and stored.
In addition, since the temperature stratification of the hot water tank is maintained without being destroyed as described above, it is not necessary to increase the circulating flow rate of the hot water in the circulation line, and the circulating flow rate reaches the hot water mixing tap . Since the temperature of the hot water to be supplied can be extremely small so that the temperature of the hot water is higher than the appropriate temperature for hot water supply, the circulation power in the circulation line can be made extremely small. Since it can be configured, the equipment cost can be reduced.
Furthermore, relatively low-temperature water supplied and stored in the lower part of the hot water tank from the water supply pipe is taken out to the cooling water pipe, the water is heated by a heat source machine, and the heated water is used as hot water for the hot water tank. By returning to the upper part, hot water can be stored in the hot water storage tank while maintaining good temperature stratification formed in the hot water storage tank. Moreover, since the low-temperature water taken out from the lower part of the hot water storage tank can be supplied to the heat source unit, the heating efficiency of the heat source unit is improved, and when the heat source unit is a cogeneration device, The cogeneration apparatus can be cooled well with low-temperature water.

  The second characteristic configuration of the circulation type hot water storage and hot water system according to the present invention is characterized in that a return pipe backflow preventing means for preventing a backflow of hot water from the heat radiating means side to the connecting portion side is provided in the return pipe. It is in.

When the pressure loss in the return line is relatively low, or when the circulating flow rate of hot water in the circulation line is relatively low, when the hot water supply is opened and the hot water supply is started, Along with a decrease in the pressure at the connecting portion, in addition to the hot water supply temperature not less than the hot water supply temperature supplied from the outgoing line side, low temperature hot water flowing back from the heat radiating means side may be supplied to the connecting portion, In some cases, the temperature of hot water discharged from the hot water tap cannot be maintained at an appropriate temperature or higher.
Therefore, according to the second characteristic configuration, by providing the return pipe backflow prevention means in the return pipe, it is possible that the low temperature hot water flows back from the heat radiating means side to the connection portion with the hot water tap during hot water supply. Since it can prevent, the temperature of the hot water discharged from a hot-water tap can be kept more than the hot water supply suitable temperature.

The third characteristic configuration of the circulating hot water storage system according to the present invention is :
The downstream side of the heat return means of the return pipe is connected to the water supply pipe, and the water supply pipe is used as a part of the return pipe.

According to the third characteristic configuration, it is possible to omit or simplify the installation of a new return pipe using the water supply pipe as a part of the return pipe, and economically according to the present invention. A circulating hot water storage system can be realized.
That is, it can be expected that there is a faucet in the vicinity of the hot water tap or integrated as a mixing tap. In this case, if the water supply pipe connected to the water tap can also be used as the return pipe, the return pipe is separately provided. There is no need for construction, and the circulation line can be constructed at low cost.
And the temperature of the hot water on the downstream side of the heat radiating means is lowered to the same as the water supply temperature by using the heat radiating means provided in the return pipe. Therefore, there is no technical problem even if the downstream side of the heat radiating means of the return pipe is connected to a water supply pipe that is not heat-resistant, and in use, hot water is discharged from the water tap through the water supply pipe. In addition, the water flowing into the water supply line from the return pipe is discharged after the same water as the water supplied to the water supply line is heated (eg, sterilized). Since it is only cooled and does not stay, there is no sanitary inconvenience. When the water tap is opened, the water discharged from the water tap is only slightly mixed with the hot water that has been cooled and brought close to the water temperature.

  According to a fourth characteristic configuration of the circulating hot water storage and hot water system according to the present invention, hot water is supplied across the hot water storage tank and the circulation pipe using a density difference formed by a temperature drop of the hot water in the heat radiating means. The point is that it is configured to circulate naturally.

According to the fourth characteristic configuration, the energy necessary for the circulation of the hot water in the circulation pipe is not dependent on the external power or the like, and the heat energy that is originally wasted due to the heat radiation is used as the driving force, thereby saving energy. In addition, both initial and running costs can be reduced, and the circulating hot water storage and hot water system according to the present invention can be realized economically.
That is, the circulating hot water storage and hot water system according to the present invention has the greatest feature in that the circulation flow rate of hot water in the circulation line is very small. The relatively hot (for example, 80 ° C.) hot water that has flowed out of the hot water tank radiates heat while flowing through the heat-reserved outgoing line, but when it reaches the connection with the hot water tap, it is suitable for hot water (for example, 60 Therefore, the amount of circulating water is very small (for example, 0.2 L / min), and it is not necessary to use a power source such as an electric pump. The hot water supply can be caused to flow by natural circulation.
The principle of natural circulation is the difference in the density of water based on the temperature difference, but the hot hot water stored in the upper part of the hot water tank is composed of an outward conduit and a return conduit with heat dissipation means. Because the cooling means closes to the water supply temperature by the heat dissipating means in the closed loop of the circulation pipe, natural convection occurs and the circulation continues. The temperature difference is sufficient to ensure the necessary natural circulation flow rate.

Further, when the heat dissipation capability of the heat dissipation means is relatively low, for example, when the heat dissipation means is configured by a so-called air cooling system that promotes heat dissipation of hot water by exchanging heat with the atmosphere, the temperature of the hot water is set in the heat dissipation means. It can be reduced only to the same extent as the low temperature water stored below the hot water tank, and the natural circulation of hot water as described above may not be sufficiently generated.
Therefore, in such a case, the natural circulation can be appropriately generated by arranging the heat dissipating means above the uppermost part of the hot water storage tank. That is, if the heat dissipating means is arranged above the uppermost part of the hot water tank, the hot water tank has a relatively low density in the height region above the boundary of the temperature stratification formed in the hot water tank. On the other hand, low temperature hot water having a relatively high density exists on the downstream side of the heat radiating means of the circulation pipe. Therefore, appropriate natural convection is generated in the circulation line so as to raise the boundary of the temperature stratification formed in the hot water tank and bring the pressure between the hot water tank and the circulation line into an equilibrium state.

  The 5th characteristic structure of the circulation type hot-water storage hot-water supply system which concerns on this invention exists in the point to which the said thermal radiation means uses a natural convection and radiation as a thermal radiation principle.

According to the fifth characteristic configuration, the heat dissipating means is configured such that at least a part of the return pipe is constituted by a non-thermal insulation pipe or a heat-conductive conductor pipe or a natural convection type heat exchanger. The circulation type hot water storage hot water supply system according to the present invention can be configured at low cost.
That is, in the present invention, since the circulation flow rate in the circulation line can be made extremely small, the amount of heat to be radiated by the heat radiating means can be small. Therefore, the heat dissipation means can be configured to use natural convection and radiation as the heat dissipation principle, and no fan is required to cause forced convection. This is particularly suitable for residential use.
Furthermore, if such a small amount of heat is dissipated, there is no need to use a special heat exchanger as a heat dissipating means, and the return pipe is made of a metal having a high thermal conductivity (for example, copper, tin, etc.). It is possible to realize a heat radiating means by using a thin tube with a good heat conductor, or by making all or part of the hot water return pipe into a non-insulating tube.

A sixth characteristic configuration of the circulation type hot water storage and hot water system according to the present invention is that a plurality of the hot and cold water mixing taps are arranged, and each of the plurality of hot and cold water mixing taps is sequentially connected to one outgoing pipe. There is in point.

According to the sixth characteristic configuration described above, it is compatible with a so-called pipe branching method in which a plurality of hot-water mixing taps are sequentially connected to one outgoing pipe, and is a general circulation type in which a plurality of hot-water mixing taps are installed. It can be applied to hot water storage and hot water supply systems and can demonstrate practicality.
Therefore, it is not necessary to provide the heat dissipating means for each of the hot and cold water mixing plugs , and it is only necessary to provide the heat dissipating means in the return pipe disposed on the downstream side of the connection part of the most downstream hot water and water mixing plugs . The hot water supply pipe length from the circulation pipe (outward pipe) to each hot water / water mixing tap can be shortened to, for example, less than 1 m, and the diameter of the hot water supply pipe can also be reduced. The amount of discarded water at that time is small, and there is almost no waiting time until hot water having an appropriate temperature or higher is discharged.

The seventh characteristic configuration of the circulating hot water storage and hot water system according to the present invention is such that the temperature of the hot water reaching the connecting portion with the hot water mixing tap connected to the most downstream side in the circulation pipe is equal to or higher than the appropriate hot water temperature. In addition, there is a circulation flow rate control means for controlling the circulation flow rate of hot water in the circulation line.

According to the seventh characteristic configuration, the circulating flow rate of hot water in the circulation pipe is appropriately maintained, and the circulating hot water storage hot water system according to the present invention using the temperature stratified hot water storage tank can be appropriately operated. .
That is, in the circulating hot water storage hot water system according to the present invention, the hot water is circulated in the circulation pipe in an appropriate flow direction (direction in which hot water is taken out from the upper part of the hot water tank and returned to the lower part of the hot water tank). It is necessary to maintain the circulating flow rate of hot water in the circulation line in an appropriate range. Therefore, the temperature of the hot water detected by the temperature detection unit installed in the vicinity of the connecting portion with the hot water mixing tap connected to the most downstream side in the circulation line becomes equal to or higher than the appropriate hot water temperature by the circulating flow rate control means. By controlling the circulating flow rate of hot water as described above, it is possible to appropriately supply hot water maintained at or above the appropriate hot water temperature to each hot water supply section.

As described above, in the circulating hot water storage hot water system according to the present invention, hot water having a temperature equal to or higher than the hot water supply temperature has reached the upstream of the hot water tap, so that if the hot water tap is opened, hot water can be used without waiting for hot water. Is possible.
Further, in the circulating hot water storage hot water system according to the present invention, the temperature of the hot water at the most downstream hot water tap only needs to be equal to or higher than the appropriate hot water temperature, and therefore, in the outgoing line from the hot water storage tank to the downstream hot water tap. The temperature drop of hot water is allowed to the maximum. Therefore, the circulation flow rate of hot water in the circulation pipe can be made extremely small as compared with the conventional case. As a result, the circulation power for circulating the hot water is reduced, the heat radiation of the pipe is reduced, the diameter of the return pipe is reduced, and The remarkable effect is that it is possible to omit the heat retention of the return pipe.
If hot water is circulated constantly, there is a negative effect that heat loss due to heat radiation from the pipe increases compared to a single-pipe hot water system that does not circulate, but this is a decrease in discarded water. This is offset by the resource saving effect. In addition, it is possible to stop the circulation operation by using a timer or the like at midnight. In this case, even if a hot water waiting time occurs, it is merely a return to the conventional single-pipe hot-water supply system. The big problem does not occur. Furthermore, in the cogeneration system of the heat main operation in which the operation must be stopped if the heat storage in the hot water storage tank expires even though there is an electric power load, A part of the heat loss can be offset by improving the operating rate and producing a lot of high-value electric power compared to heat. In order to continue power generation, it can be said that it is sufficiently energy-saving compared to the main operation that actively dissipates heat using a cooling tower or the like.

  An embodiment of a circulating hot water storage and hot water system (hereinafter referred to as the present invention system) according to the present invention will be described with reference to the drawings.

[First Embodiment]
A system 100 according to the first embodiment will be described with reference to FIG.
The system 100 according to the present invention includes a hot water storage tank 1 for storing hot water, an outgoing line 8 extending from the hot water storage tank 1 to a connecting part 6 of a hot water mixing tap (an example of a hot water tap), and the hot water storage tank from the connecting part 6. 1 and a circulation line 10 consisting of a return line 9 leading to 1, circulates hot water stored in the hot water reservoir 1 through the circulation line 10 and supplies hot water from the circulation line 10 to the hot water mixing tap 5. It is configured as a circulating hot water storage system.

In such a system according to the present invention, the hot water flowing out from the hot water storage tank 1 to the outgoing pipe 8 of the circulation pipe 10 reaches the connecting part 6 with the hot water mixing tap 5 and still has an appropriate hot water supply temperature (for example, 60 ° C.). The hot water / water mixing tap 5 can be connected to the circulation line 10 via the hot water supply line 7 that is relatively short (for example, within 1 m). Therefore, when the hot water mixing tap 5 is opened and hot water is used, hot water having an appropriate temperature or higher is circulated to the connecting portion 6 immediately upstream of the hot water mixing tap 5, so that it is immediately connected with almost no time delay. The hot water is supplied from the section 6 to the hot water mixing tap 5 and discharged.
Further, when the circulation pipe 10 is installed below the hot water mixing tap 5, natural convection occurs, and the temperature of hot water in the hot water supply pipe 7 branched from the circulation pipe 10 may increase. I can expect.

The hot water tank 1 is configured to store hot water heated by the heat source unit 30. Specifically, the hot water tank 1 is laid from the lowermost part 3 of the hot water tank 1 to the uppermost part 2 via the heat source unit 30. The cooling water pipe 31 is provided with a cooling water pump 32 (for example, incorporated in the heat source device 30) that allows water to flow from the lowermost portion 3 side to the uppermost portion 2 side of the hot water tank 1. By operating the cooling water pump 32 and flowing water through the cooling water pipe 31, the water taken out from the lowermost part 3 side of the hot water tank 1 to the cooling water pipe 31 is heated by the heat source unit 30, and the heating is performed. The heated water is supplied to the uppermost part 2 side of the hot water storage layer 1 as hot water.
As the above-mentioned heat source apparatus 30 can utilize the cogeneration system and a heat pump apparatus such as an engine driven generator or fuel cell.

Furthermore, relatively low temperature clean water is supplied to the lowest part 3 of the hot water tank 1 from a water supply line 25 that supplies clean water through a water meter 26, and the low temperature water in the lowest part 3 of the hot water tank 1 is supplied. The hot water storage tank 1 is configured in a temperature stratification type that stores hot water in a form in which temperature stratification is formed by returning to the uppermost part 2 of the hot water storage tank 1 after being heated to an appropriate target hot water storage temperature or higher by the heat source device 30. ing.
Specifically, a temperature sensor 33 that detects the temperature of hot water supplied to the uppermost side 2 of the hot water tank 1 in the cooling water pipe 31 is provided, and the power of the cooling water pump 32 is controlled based on the detection result of the temperature sensor 33. Since the temperature of the hot water supplied to the uppermost part 2 side of the hot water tank 1 is controlled to be equal to or higher than an appropriate temperature, the hot water stored in the hot water tank 1 is heated to the uppermost part 2 side. In the form of forming a layer and forming a low temperature layer on the lowermost part 3 side, temperature stratification is formed and stored.
In addition, about the auxiliary | assistant equipment etc. which are normally installed, such as the flow regulating valve accompanying the cooling water pipe 31, such as the pressure reducing valve (or pressure reducing check valve) and the relief valve accompanying the hot water tank 1, illustration is abbreviate | omitted. There are also things.

The circulation line 10 is configured so that hot water flows out from the uppermost part 2 of the hot water tank 1 to the outgoing line 8 and hot water flows into the lowermost part 3 of the hot water tank 1 from the return line 9 to the hot water tank 1. In addition, the return pipe 9 of the circulation pipe 10 is provided with a heat dissipating means 20 that promotes heat dissipation of the hot water.
Therefore, the temperature of the hot water flowing out from the uppermost part 2 of the hot water storage tank 1 to the outgoing line 8 and returned to the return line 9 without being supplied to the hot water mixing tap 5 by the heat radiating means 20 (for example, 60 ° C.). Even if it flows into the lowermost part 3 of the hot water tank 1, it is lowered to a temperature at which the temperature stratification of the hot water tank 1 is not destroyed.
Moreover, since the temperature of the hot water in the lowermost part 3 of the hot water tank 1 is kept at a relatively low temperature (for example, 25 ° C.), when the heat source device 30 is a cogeneration device, the lowermost part 3 of the hot water tank 1. The cogeneration apparatus is sufficiently cooled by the low-temperature water taken out from the water to the cooling water pipe 31.

The forward duct 8 can be configured with normal specifications, such as a copper pipe kept warm with a foamed polyurethane molding material.
And since the temperature stratification of the hot water tank 1 is not destroyed and the temperature of the hot water flowing out from the uppermost part 2 of the hot water tank 1 to the outgoing pipe 8 is kept at a high temperature almost always, the hot water in the circulation line 10 is kept. Even if the circulation flow rate is set to a very small amount (for example, 0.21 L / min) without increasing the circulation flow rate, the temperature of the hot water reaching the connecting portion 6 with the hot water mixing tap 5 is maintained at the hot water supply proper temperature or higher.

Although a general heat exchanger can be used as the heat radiating means 20, since the circulating flow rate of hot water in the circulation pipe 10 is extremely small as described above, the amount of heat to be radiated is small (for example, Therefore, the fan for forced convection can be simplified or omitted, and a natural convection and radiation can be used as a heat dissipation principle like a natural convection type heat exchanger.
In addition, since the flow rate of the hot water flowing through the return line 9 is small and the temperature is low, the return line 9 has a small diameter pipe made of copper or resin such as polyethylene, which is several times smaller than the outgoing line 8. Can be used in bare tubes.

  Note that the amount of heat to be radiated in the heat radiating means 20 is extremely small, and the hot water supply in the return pipe 9 should be lowered in temperature before returning to the hot water tank 1, so that all or part of the return pipe 9 is not kept warm. The heat dissipation means 20 can be configured by a tube. If the return pipe 9 is short and cannot radiate heat, all or a part of the return pipe 9 is constituted by a bare metal pipe (thermal conductor pipe) such as copper, or a plurality of metal thin pipes are arranged in parallel. It is sufficient to increase the heat transfer area by piping. Thus, the heat dissipating means 20 can be configured at low cost.

  The circulation line 10 is provided with a circulation pump 11 for forcibly circulating hot water in a direction from the outward line 8 toward the return line 9 and a circulation flow rate adjusting valve 12 capable of adjusting the circulation flow rate. Yes. The circulation pump 11 and the circulation flow rate adjustment valve 12 can be installed in the outgoing line 8, but the return line 9 is provided for the purpose of improving the durability performance by handling hot water at relatively low temperatures. is set up. Moreover, by installing the circulation pump 11 in the return pipe 9, the hot water tank 1 can be favorably pressurized.

In such a system 100 of the present invention, if the circulation flow rate of the hot water in the circulation line 10 is excessive, the heat radiating means 20 cannot radiate heat, and the hot water is returned to the lowermost part 3 of the hot water tank 1 to return the temperature. If the stratification is destroyed or cooling of the cogeneration device as the heat source device 30 is poorly cooled, and the circulating flow rate of the hot water in the circulation line 10 is too small, In some cases, the temperature of the hot water that reaches the connecting portion 6 decreases, and the purpose of the immediate hot water supply cannot be achieved.
Further, since the circulation flow rate of the hot water in the circulation pipe 10 may be extremely small (for example, 0.21 L / min), the circulation pump 11 can be a small one having a small discharge capacity. It is difficult to obtain the electric circulation pump 11, and the circulation flow rate of the hot water in the circulation line 10 tends to be excessive.

  Therefore, the system of the present invention is provided with a control device configured by a computer, and the control device is configured such that the temperature of the hot water reaching the connecting portion 6 with the hot water mixing tap 5 in the circulation line 10 is equal to or higher than the appropriate hot water temperature. In this way, it is configured to function as a circulation flow rate control means 35 that controls the circulation flow rate of hot water in the circulation line 10.

That is, a temperature sensor 14 for detecting the temperature of hot water that has flowed out from the uppermost part 2 of the hot water tank 1 to the outgoing line 8 and returned to the return line 9 without being supplied to the hot water mixing tap 5 is provided. The control means 35 controls the power of the circulation pump 11 or the opening degree of the circulation flow rate adjustment valve 12 based on the detection result of the temperature sensor 33, and keeps the temperature of the hot water detected by the temperature sensor 14 above the appropriate hot water temperature. It is configured as follows.
It should be noted that the temperature sensor 14 should be installed at a position where the representative temperature of the connecting portion 6 with the hot and cold water mixing tap 5 can be detected in the circulation pipe 10. For example, if the temperature sensor 14 is installed at a non-insulated position or the like of the return pipe 9, the temperature drop of the hot water is quick and sufficient for maintaining the temperature of the hot water at the connection portion 6. This is because the circulation flow rate in the case increases and goes against energy saving.

  Furthermore, the circulation flow rate control means 35 may be configured to circulate hot water in the circulation line 10 continuously for 24 hours, but the temperature of the hot water detected by the temperature sensor 14 is set as an appropriate hot water temperature. If the temperature is lower than the lower limit temperature (for example, 60 ° C.), the operation of the circulation pump 11 is started to circulate the hot water in the circulation line 10, and if the temperature of the hot water is higher than the upper limit temperature (for example, 75 ° C.), An ON-OFF operation such as stopping the operation of the circulation pump 11 can also be executed, and this method is used when it is difficult to select the circulation pump 11 because the circulation flow rate of hot water in the circulation line 10 is too small. It is a convenient method if used for. Further, by using the time control function of the circulation flow rate control means 35, for example, at midnight when hot water is not used, the operation of the circulation pump 11 can be stopped to save energy.

  Moreover, if hot water at a constant flow rate is allowed to flow in the return line 9, the temperature of the hot water reaching the connection 6 with the hot water mixing tap 5 in the circulation line 10 can be maintained at or above the appropriate temperature for hot water supply. The power control of the circulation pump 11 or the opening control of the circulation flow rate adjusting valve 12 as described above is omitted, and the constant flow valve (always constant even if the differential pressure between the upstream side and the downstream side fluctuates). It is easy to keep the flow rate of hot water in the return pipe 9 constant by a valve having a function of flowing a set flow rate. Further, this constant flow valve can be replaced by a pressure reducing valve, a manual adjustment valve, a thin tube or the like.

Further, when the hot water mixing tap 5 is opened, the pressure at the connection portion 6 of the circulation line 10 decreases, so that not only hot water having an appropriate hot water supply temperature is supplied to the connection portion 6 from the forward line 8, There is a concern that low temperature hot water flows backward from the return pipe 9. In particular, in the system 100 of the present invention, since the circulation flow rate of the circulation line 10 is small, the risk of such backflow increases.
Accordingly, the return pipe 9 allows a circulating flow of hot water from the connecting portion 6 side toward the heat radiating means 20 side, and prevents a reverse flow of the hot water from the heat radiating means 20 side toward the connecting portion 6 side. A check valve 13 is provided as a road backflow prevention means. In addition, when a device installed in the return pipe 9 such as a circulation flow rate adjusting valve 12 or a pressure reducing valve, which will be described later, has a backflow prevention function, or when a backflow in the return pipe 9 is sufficiently small, etc. The installation of such a check valve 13 can be omitted.

Moreover, the hot-water mixing tap 5 is configured to be able to discharge the clean water supplied from the water supply pipe 25 in a form separate from or mixed with the hot water supplied from the hot water supply pipe 7. In addition, when mixing hot water and clean water and discharging, an automatic temperature adjustment function is provided to prevent temperature fluctuations in the discharged water due to fluctuations in the temperature of hot water supplied from the circulation pipe 10. It is convenient to use a hot and cold water mixing tap 5 with built-in .

  In the case of the system 100 of the present invention, the circulation by the circulation pump 11 is a circuit other than the circuit constituted by the hot water storage tank 1 and the circulation pipe 10, specifically, the return pipe 9, the water supply pipe 25, and the hot water mixing. It may also occur in a circuit via the plug 5. Further, if the circulation pump 11 is provided in the outgoing pipe 8, there is a possibility that circulation also occurs in a circuit passing through the hot water storage tank 1, the outgoing pipe 8, the hot water mixing tap 5, and the water supply pipe 25. In order to avoid such circulation, backflow prevention means such as a check valve 37 may be provided in the hot water supply line 7 and the water supply line 25. Further, when such a backflow prevention function is built in the hot / cold mixing tap 5, the check valve 37 can be omitted.

[Second Embodiment]
A system 200 according to the second embodiment will be described with reference to FIG. In addition, about the structure similar to other embodiment, the description may be omitted using the same code | symbol.

  As with the hot-water mixing tap 5, the hot water supply section and the water supply section are generally provided adjacent to each other, and the hot water supply pipe 25 is usually laid adjacent to the hot water supply pipe 7. .

  Therefore, in the system 200 of the present invention, the water supply pipe 25 is connected to both the lowermost part 3 of the hot water tank 1 and the hot water mixing tap 5 to supply the hot water supplied to the lowermost part 3 of the hot water tank 1 with the hot water mixing plug. 5 is connected to the water supply pipe 25 on the downstream side of the heat radiating means 20 of the return pipe 9, so that the water supply pipe 25 is used as a part of the return pipe 9. The cost reduction is achieved by omitting or simplifying the installation of the return pipe 9.

[Third Embodiment]
A system 300 according to the third embodiment will be described with reference to FIG. In addition, about the structure similar to other embodiment, the description may be omitted using the same code | symbol.

As a means for circulating hot water in the circulation line 10, a circulation pump is commonly used. However, in the present system 300, the circulation flow rate of hot water in the circulation line 10 is extremely small. Further, in order to return the hot water to the lowermost part 3 of the hot water tank 1, heat radiation by the heat radiation means 20 is required. If the heat is dissipated, the hot water will increase in density as the temperature drops, so it tends to descend according to gravity. On the other hand, in the hot water tank 1, since hot hot water is stored on the uppermost part 2 side, a pressure to increase is exerted. Therefore, if both are connected by the closed-loop circulation line 10, natural circulation based on the density difference is generated, and it becomes possible to cause circulation of hot water in the circulation line 10 necessary for the system 300 of the present invention.
Therefore, in the system 300 of the present invention, the circulation pump 11 provided in the first embodiment described above is omitted, and the circulation between the hot water storage tank 1 and the hot water tank 1 is made using the density difference formed by the temperature drop of the hot water in the heat radiating means 20. It is comprised so that hot-water supply may be circulated naturally over the pipe line 10, and energy saving property and economical efficiency are improved. Further, since the heat dissipating means 20 is disposed above the uppermost portion 2 of the hot water tank 1 in the vertical direction, the boundary of the temperature stratification formed in the hot water tank 1 is raised to raise the hot water tank 1. Therefore, natural circulation of hot water in the circulation pipe 10 as described above is appropriately generated so that the pressure between the pipe and the circulation pipe 10 is in an equilibrium state.

[Fourth Embodiment]
A system 400 according to the fourth embodiment will be described with reference to FIG. In addition, about the structure similar to other embodiment, the description may be omitted using the same code | symbol.

Only one hot-water tap, such as the hot-water mixing tap 5, is rarely provided for the circulation line 10, and even for home use, it can be installed in multiple locations such as kitchens, washrooms, and baths. It is general, and it is only for such multiple installations that there is a significance of installation of immediate hot water supply by circulating hot water.
Moreover, the hot water supply pipe line 7 is generally constructed by a pipe branching method. This is the same even in the water supply pipeline 25. As another hot water pipe construction method, the header construction method is known, but this header construction method is a construction method in which the header and each hot water tap are individually connected using a small-diameter pipe, reducing the amount of accumulated water in the pipeline. It is intended to reduce the amount of discarded water and the waiting time for hot water supply, and shares some purposes with the present invention. However, in the header construction method, in general, the length of the hot water supply pipe line from the header becomes long, the equipment cost becomes high, and the heat radiation area increases, so there is an inconvenient aspect for circulating hot water. .

Therefore, in the system 400 of the present invention, a hot and cold water mixing tap is used by a so-called pipe branching method in which a plurality of (for example, three) hot water and water mixing taps 5a, 5b and 5c are sequentially connected to the outgoing pipe 8 of one circulation pipe 10. A plurality of 5 are installed.
That is, in the pipe branching method, one outgoing pipe 8 is arranged in the vicinity of the place where each of the hot and cold water mixing plugs 5a, 5b and 5c is installed, and from there to each of the hot and cold water mixing plugs 5a, 5b and 5c. The hot water supply pipes 7a, 7b, and 7c are branched from the connecting portions 6a, 6b, and 6c, and the hot and cold water mixing plugs 5a, 5b, and 5c are individually connected to the one outgoing pipe 8. In a house, the length of each hot water supply pipe 7a, 7b, 7c is usually less than 1 m. This corresponds to the length from the forward line 8 under the floor to the hot water tap such as the hot and cold water mixing tap 5 attached to the sink or bathtub.

Further, in this case, the heat radiating means 20, the circulation pump 11, the circulation flow rate adjustment valve 12, the check valve 13 and the like are connected to the hot water / water mixing plug 5c connected to the most downstream side in the circulation pipe 10 from the connection portion 6c. May be provided in the downstream return pipe 9.
In the system 400 of the present invention, the water supply pipe 25 is used as a part of the return pipe 9 as in the second embodiment described above, and further, as in the third embodiment, the circulation pump 11 is used. The hot water supply water can be naturally circulated across the hot water tank 1 and the circulation pipe 10.

  The circulation flow rate control means 35 is configured to supply hot water in the circulation line 10 so that the temperature of the hot water reaching the connecting part 6c with the hot water tap 5c connected to the most downstream side in the circulation line 10 is equal to or higher than the appropriate hot water temperature. It is comprised so that the circulation flow rate of may be controlled. Therefore, it is desirable to install the temperature sensor 14 in the vicinity of the connecting portion 5c.

  The circulation type hot water storage and hot water system according to the present invention can reduce the circulation power and heat dissipation loss of hot water as much as possible even if the hot water storage tank is configured as a temperature stratification type. In order to avoid it, the present invention can be effectively used as a circulating hot water storage hot water system capable of realizing immediate hot water supply by circulating hot water in the circulation pipeline.

The schematic block diagram which shows 1st Embodiment of the circulation type hot water storage hot water supply system which concerns on this invention. The schematic block diagram which shows 2nd Embodiment of the circulation type hot water storage hot water supply system which concerns on this invention. The schematic block diagram which shows 3rd Embodiment of the circulation type hot water storage hot water system which concerns on this invention. The schematic block diagram which shows 4th Embodiment of the circulation type hot water storage hot water system which concerns on this invention. Schematic configuration diagram of a conventional circulating hot water storage system

Explanation of symbols

1: Hot water tank 2: Upper part 3: Lower part 5, 5a, 5b, 5c: Hot and cold water mixing tap (an example of a hot water tap)
6, 6a, 6b, 6c: Connection part 8: Outward pipe line 9: Return pipe line 10: Circulation line 20: Heat radiation means 25: Water supply line 35: Circulation flow rate control means 100, 200, 300, 400: Circulation type Hot water storage system

Claims (7)

A hot water storage tank for storing hot water, and a circulation pipe composed of an outward pipe line from the hot water tank to a connection part of the hot water mixing tap and a return pipe line from the connection part to the hot water storage tank. A circulating hot water storage and hot water system that circulates hot water stored in the circulation line and supplies hot water from the circulation line to the hot water mixing tap ,
The hot water storage tank is configured in a temperature stratification type that stores hot water in a form that forms temperature stratification,
The circulation pipe is connected to the hot water tank in a form in which the hot water flows out from the upper part of the hot water tank to the outgoing pipe and hot water flows into the lower part of the hot water tank from the return pipe. And
Wherein the recovery pipe, Rutotomoni includes a radiator means to promote heat radiation of the hot water,
A water supply pipe for supplying clean water to the lower part of the hot water tank, and a cooling water pipe laid to reach the upper part of the hot water tank from the lower part of the hot water tank via a heat source device to be cooled, The water taken out from the lower part of the hot water storage tank to the cooling water conduit is heated by the heat source unit, and then returned to the upper part of the hot water storage tank.
In a configuration for supplying clean water from the water supply pipe to the hot water mixer tap,
The circulation type in which the hot-water mixing tap is configured to be able to discharge the clean water supplied from the water supply pipe separately from the hot water supplied from the forward pipe or mixed with the hot water. Hot water storage hot water system.   The circulating hot water storage and hot water supply system according to claim 1, wherein a return pipe backflow preventing means for preventing a backflow of hot water from the heat radiating means side toward the connecting portion side is provided in the return pipe path.   The circulating hot water storage according to claim 1 or 2, wherein a downstream side of the heat release means of the return pipe is connected to the water supply pipe, and the water supply pipe is used as a part of the return pipe. Hot water system.   The hot water supply is configured to naturally circulate over the hot water storage tank and the circulation pipe using the density difference formed by the temperature drop of the hot water supply in the heat radiating means. The circulating hot water storage system according to any one of the above.   The circulation type hot water storage hot water supply system according to any one of claims 1 to 4, wherein the heat dissipating means uses natural convection and radiation as a heat dissipation principle. The circulation type according to any one of claims 1 to 5, wherein a plurality of the hot and cold water mixing plugs are arranged, and each of the plurality of hot and cold water mixing plugs is sequentially connected to the one outgoing pipe. Hot water storage hot water system. Circulation for controlling the circulation flow rate of hot water in the circulation line so that the temperature of the hot water reaching the connecting point with the hot water mixing tap connected to the most downstream side in the circulation line is equal to or higher than the appropriate temperature for hot water supply. The circulation type hot water storage hot water supply system according to any one of claims 1 to 6, further comprising a flow rate control unit.

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