JP5546477B2 - A water supply apparatus having a primary heat source and a secondary heat source - Google Patents

Description

  The present invention includes a heat recovery unit configured to store, in a heat storage unit, primary hot water preheated using, for example, heat collected by a solar heat collector or heat of exhaust gas from a cogeneration system as a primary heat source, and The present invention relates to a hot water supply system including a secondary heat source that further heats the primary hot water stored in the heat storage unit and a hot water supply facility that supplies the reheated secondary hot water to a hot water use place.

  A hot water supply system of the above-described form is known. In such a system, the heat from the solar heat as the primary heat source and the heat from the cogeneration system is unstable as a heat supply source. In the case of solar heat, it depends on the weather, and the exhaust gas from the cogeneration system. In this case, it depends on the heat demand or power demand loaded on the system. For this reason, for example, in a hot water supply system using solar heat, it is difficult to maintain the hot water temperature (temperature of the primary hot water) on the solar heat collector side at a desired constant temperature for a long time, and a secondary water source for obtaining secondary hot water. Hot water supply at the temperature desired by the user (secondary hot water) by starting or stopping the heating of the side heat source (auxiliary heating by the auxiliary heat source device) according to the temperature of the primary hot water on the solar collector side Patent Document 1 or 2 proposes a solar hot water supply system that can achieve the above.

JP 2002-213818 A JP 2002-213819 A

  As described above, in a heat recovery unit having a heat storage unit that uses an unstable heat source as a primary heat source, collects heat from the primary heat source, and stores hot water as primary hot water, the hot water temperature in the heat storage unit May remain at a temperature of 60 ° C. or lower for a long time. If regular cleaning is not performed and hot water is left at a temperature of 60 ° C. or lower for a long time, the hot water may be contaminated with bacteria. In order to prevent the contamination, it is necessary to reheat the stored hot water to a temperature of 60 ° C. or higher, or replace it with new hot water without leaving it in the heat storage unit for a long time.

  In the conventional hot water supply system using solar heat that has been proposed, this point is not taken into consideration. In the unlikely event that hot water is stored in the heat storage section on the solar heat collector side for a long time of, for example, about 100 hours at a temperature of less than 60 ° C. The possibility that hot water can be contaminated with bacteria should not be ignored at all.

  This invention is made | formed in view of the above situations, The heat recovery unit provided with the thermal storage part which collect | recovers the heat | fever from a primary side heat source, The secondary side heat source and hot water supply which further heat the said primary hot water In a hot water supply system comprising a hot water supply facility equipped with equipment, it is possible to reheat hot water stored in the heat storage unit when necessary, thereby avoiding contamination of the hot water in the heat storage unit Disclosed is a hot water supply system as a first problem.

  A second object of the present invention is to disclose a hot water supply system capable of simplifying the manufacturing and reducing the manufacturing cost.

  Moreover, in said hot water supply system, it is set as the 3rd subject to disclose the hot water supply system which is user-friendly for the user side by preventing hot water more than an initial setting from coming out from hot water supply equipment.

  Further, in the above hot water supply system, it is a fourth object of the present invention to disclose a hot water supply system that is easy to use for the user side so that it can appropriately cope with the demand for hot water on the hot water supply facility side. Let it be an issue.

A hot water supply system according to the present invention includes a heat recovery unit including a primary heat source and a heat storage unit that recovers heat from the primary heat source, and heats primary hot water preheated by the heat storage unit of the heat recovery unit. A hot water supply system comprising a secondary heat source and hot water supply equipment for supplying secondary hot water heated by the secondary heat source to a hot water use place, wherein the hot water supply system further includes hot water in a heat storage section of the heat recovery unit. To reheat the hot water in the heat storage unit with a secondary heat source of the hot water supply facility and then return it to the heat storage unit again, a water supply line to the heat storage unit at the time of reheating, and the heat storage unit And a bypass pipe for directly connecting the primary hot water pipe to the secondary heat source, and a control means for switching the reheating pipe system and the bypass pipe between a use state and a non-use state.

  In the hot water supply system described above, the type of primary heat source is arbitrary, but in the case of a heat source with a non-constant amount of heat, such as heat from exhaust gas from a solar heat collector or cogeneration system, the hot water supply system according to the present invention is Works particularly effectively.

  The hot water supply system according to the present invention uses a reheat piping system that reheats the hot water in the heat storage unit on the heat recovery unit side with the secondary heat source on the hot water supply facility side, and then returns the hot water in the heat storage unit again. Control means for switching between a state and a non-use state, and when it is necessary to reheat the hot water in the heat storage section on the heat recovery unit side, the control means normally puts it in a non-use state. The reheat piping system is switched to the use state, and the bypass pipe that is closed during normal operation is opened, that is, in the use state, so that the hot water in the heat storage section can be recirculated without affecting the hot water from the hot water supply equipment side. Heating can be performed easily and reliably.

  In the hot water supply system according to the present invention, the number of the heat recovery units may be one, but preferably two or more heat recovery units are provided, and the primary hot water from each of the heat recovery units merges into one in the header. In such a state, the heat is supplied to the secondary heat source provided in the hot water supply facility. In this aspect, a standardized heat recovery unit with a relatively small capacity is prepared in advance, and the required number of standardized heat recovery units are combined in parallel according to the hot water supply load on the hot water supply equipment side. By using the optimal number of heat recovery units according to the hot water supply load and installation location required for the hot water supply system to be constructed, the entire hot water supply system can be manufactured without waste and at low cost. . Also, the manufacturing cost can be reduced by standardizing the heat recovery unit.

  In one aspect of the hot water supply system according to the present invention, the control means for switching the reheating piping system between the use state and the non-use state is a temperature measurement means for measuring the temperature of the hot water in the heat storage section and a primary in the heat storage section within a predetermined time. Hot water use detecting means for detecting that hot water has not been supplied to the secondary heat source more than a certain number of times, and the temperature measuring means has the temperature of the hot water in the heat storage section continuously longer than a certain time and not higher than a certain temperature. And when the hot water use detecting means detects that the primary hot water in the heat storage section has not been supplied to the secondary heat source more than a certain number of times within the predetermined time, the reheat piping system is used. It is characterized by switching to.

  Even if the hot water system in this aspect is a case where the temperature of the hot water in the heat storage unit is kept below the predetermined temperature for a long time, the hot water stored in the heat storage unit is replaced with new hot water over time. It is based on the fact that contamination by bacteria etc. does not occur in the hot water of the water, and by providing this form of control means, the hot water in the heat storage section will be contaminated for a long time without unnecessarily increasing the number of times of reheating. Can be prevented.

  The fixed time, the fixed temperature, and the fixed number of times are determined experimentally in accordance with the use environment of the hot water supply system and the natural environment in which the hot water supply system is installed. As an example, the “fixed time” is 100 hours. The “constant temperature” is 60 ° C., and the “constant number” is 20 times. It is a preferable aspect that the control device has a possible setting range for these values and can set an appropriate value within the range. As an example of the possible setting range, “fixed time” is 1 to 1. 400 hours, “constant temperature” is 10 to 65 ° C., and “constant number” is 1 to 100 times.

  In the hot water supply system including the control means, the hot water use detection means may be a flow meter, but may be a thermometer provided in a pipe on the downstream side of the heat storage unit. And the measurement whether the primary warm water in the heat storage part is supplied to the secondary side heat source within a certain number of times or more is performed by measuring the number of times the thermometer rises above a certain temperature. Like that. In this aspect, the thermometer may also function as a temperature measuring unit that measures the temperature of the hot water in the heat storage unit.

  In this aspect, the state in which the thermometer rises above a certain temperature means a state in which the hot water in the heat storage unit has been heated by a certain temperature by recovering heat from the primary heat source, Occurring a certain number of times within a certain period of time is surely replaced with hot water having a higher temperature even when the temperature of the warm water stored in the heat storage unit is low. Therefore, when satisfy | filling this condition, it is not necessary to reheat the warm water in a thermal storage part.

  In the above aspect, whether or not to reheat can be determined only by information from the installed thermometer, and other equipment such as a flow meter is not required, so a hot water supply system at a low cost Can be constructed.

  When two or more heat recovery units are used, the thermometer is arranged in each heat recovery unit, and it is determined whether or not reheating of the hot water in the heat storage unit is necessary for each heat recovery unit. Heating may be performed. However, in this case, the cost of equipment such as a thermometer and the cost required for the control system increase. By disposing only one thermometer in the header or on the downstream side thereof, there is a possibility that information on whether or not reheating is necessary can be obtained while avoiding an increase in cost. However, in this case, there is an inconvenience that the determination is wrong if the temperature in each heat recovery unit is not uniform.

  In a further preferred aspect of the hot water supply system of the above aspect according to the present invention, the thermometer is disposed in the vicinity of the pipe in the heat recovery unit having the shortest pipe length in the pipe length from the heat storage section to the header. Is done.

  In general, the longer the pipe length, the higher the pipe resistance and the lower the flow rate per fixed time. That is, even in a hot water supply system having two or more heat recovery units, the flow rate of hot water flowing into the header changes according to the length of the pipe length from the heat storage section to the header, and the heat with the longest pipe length is obtained. In the recovery unit, the flow rate flowing into the header from the heat storage section is also minimized. In other words, if the pipe length is in the range of about 1.5 m to 7 m, the heat radiation amount is limited, and the hot water temperature in the heat storage section in two or more heat recovery units is the heat recovery with the longest pipe length. The possibility of the highest temperature in the heat storage section of the unit is extremely high. Therefore, conversely, by performing the reheating treatment in the hot water supply system based on the temperature information described above with the thermometer provided in the vicinity of the shortest pipe line where the inside of the heat recovery unit has a low temperature, more appropriate reheating is performed. Starting conditions can be obtained.

  In one aspect of the hot water supply system according to the present invention, an outlet side thermometer is further provided on the hot water outlet side of the heat storage unit, and the control means has a measured value of the outlet side thermometer equal to or higher than a certain temperature. The bypass pipe is opened to stop water supply to the heat storage section.

  In the hot water supply system according to the present invention, when the hot water temperature (primary hot water temperature) on the hot water outlet side of the heat storage section exceeds the set value, the primary hot water is further heated by the secondary heat source, Hot water (secondary hot water) that has reached a high temperature exceeding the temperature is supplied from the hot water supply equipment, which is not preferable. The above hot water supply system is designed to avoid the occurrence of such high temperature hot water, and when the outlet thermometer installed on the hot water outlet side of the heat storage section shows a value higher than the set value, By opening the bypass pipe and supplying the water supply to the heat storage unit to the secondary heat source as it is, not to the heat storage unit, it is possible to prevent the secondary hot water from exceeding the use reference temperature.

  In still another aspect of the hot water supply system according to the present invention, the inlet pressure gauge upstream of the bypass conduit in the water supply conduit to the heat storage section and the primary hot water conduit from the heat storage section to the secondary heat source An outlet pressure gauge downstream from the bypass pipe, and further includes a differential pressure detecting means for measuring a differential pressure between the outlet pressure and the inlet pressure, and the control means is a measured value of the differential pressure detecting means. When the pressure exceeds a certain value, the bypass pipe is opened to supply a part of the water supply directly to the primary hot water pipe.

  In the hot water supply system described above, when the demand for hot water at the hot water supply facility increases or when the hot water supply pressure to the heat storage unit is high, the heat storage unit is utilized using a bypass circuit. By supplying a part of the water supply to the secondary side heat source, it is possible to effectively prevent erosion and leakage due to unnecessary pressure loss and excessive flow rate.

  According to the present invention, a hot water supply system including a heat recovery unit including a heat storage unit that recovers heat from a primary side heat source, and a hot water supply facility including a secondary side heat source that further heats the primary hot water and a hot water supply facility. In this case, the hot water stored in the heat storage unit can be reheated when necessary, and the hot water in the heat storage unit can be effectively avoided from being contaminated with bacteria.

  Moreover, in the preferable aspect of said hot-water supply system, simplification of manufacture and reduction of manufacturing cost are also attained. Furthermore, a hot water supply system that is easy to use for the user side can be obtained by preventing hot water having an initial setting or more from coming out of the hot water supply facility. Furthermore, a hot water supply system that is easy to use for the user side can be obtained by appropriately dealing with the demand for hot water on the hot water supply equipment side.

The figure explaining the whole hot-water supply system structure by this invention. The figure for demonstrating in more detail the opening / closing of the cutoff valve and the flow of water supply when the hot water supply system by this invention exists at the time of normal operation. The figure for demonstrating in more detail the opening / closing of the cutoff valve and the flow of water supply when the hot-water supply system by this invention is at the time of reheating operation | movement. The figure for demonstrating in more detail the opening / closing of a shut-off valve and the flow of water supply when the hot water supply system by this invention is at the time of high temperature hot-water supply prevention operation. The figure for demonstrating in detail the opening / closing of a shut-off valve, and the flow of water supply when the hot water supply system by this invention is at the time of pressure drop prevention operation | movement. The figure for demonstrating the distance relationship between a water supply going-out header and a water supply return header, and each thermal storage part.

  Hereinafter, an embodiment of the hot water supply system according to the present invention will be described by taking as an example the case where the primary heat source is solar heat.

  FIG. 1 is a diagram for explaining an embodiment of a hot water supply system according to the present invention. FIG. 1 (a) shows the overall configuration, and FIG. 1 (b) shows a heat recovery unit for recovering solar heat used there. One of them. In this example, the hot water supply system A includes a plurality (three in the illustrated example) of heat recovery units B and a hot water supply facility C.

The heat recovery unit B includes a heat collection unit 1 that collects the heat of sunlight and a heat storage unit (hereinafter referred to as a heat storage tank) 5. The heat collecting section 1 is formed by arranging a required number of conventionally known solar heat collecting plates in series. Here, five heat collecting plates are used and have a heat collecting surface of 10 m ² as a whole. The heat collecting unit 1 is filled with antifreeze as a heat medium, and the heat medium heated by solar heat circulates between the heat storage tank 5 through the resin pipe 2. The heat storage tank 5 is connected to the resin pipe 2 but has a heat exchanging section 3. The water supplied from the water pipe D to the heat accumulating tank 5 is heat that flows through the heat exchanging section 3. It is preheated by heat exchange with the medium and becomes primary hot water. That is, solar heat is stored in the stored water in the heat storage tank 5. The heated primary hot water is stored in the heat storage tank 5 and is sent to the hot water supply facility C through the primary hot water discharge pipe 7 when necessary.

  As shown in FIG. 1A, the three heat recovery units B are arranged in parallel, and the water supplied from the water supply pipe D to the water supply header 8 is divided into three by the water supply header 8. Then, it flows into the heat storage tank 5 from the bottom of each heat storage tank 5 through each water supply pipe 6. The primary hot water heated in each heat storage tank 5 is sent out from the upper part of each heat storage tank 5 through each primary hot water discharge pipe 7, and merges at the feed water return header 9. The primary hot water merged at the feed water return header 9 is sent to the hot water supply facility C through the primary hot water pipe 10. The number of heat recovery units B is arbitrary and may be one or four or more. An appropriate number is selected in consideration of hot water demand on the hot water supply facility C side.

  The hot water supply facility C includes a gas heat source device 11 as a secondary side heat source, a hot water storage tank 12, and a hot water outlet 13. The primary hot water sent to the hot water storage tank 12 and stored for hot water is sent to the gas heat source unit 11 and heated to become secondary hot water according to the demand on the hot water outlet 13 side. The heated hot water is returned to the hot water storage tank 12 and the hot water in the hot water storage tank 12 rises. The secondary hot water in the hot water storage tank 12 is sent to the hot water outlet 13 through the hot water supply pipe 14, and the secondary hot water that has not been used is returned to the hot water storage tank 12 through the hot water supply return pipe 15.

In addition to the above configuration, the hot water supply system A according to the present invention further includes means (not shown in FIG. 1) for reheating the primary hot water in the heat storage tank 5 of the heat recovery unit B. . That is, the hot water supply system A according to the present invention includes a reheating piping system that heats the primary hot water in the heat storage unit 5 with the secondary heat source (gas heat source device 11) of the hot water supply facility C and then returns the heat to the heat storage tank 5 again. A bypass pipe for directly connecting a water supply pipe to the heat storage section and a primary hot water pipe from the heat storage section to a secondary heat source during reheating, and the reheating pipe system and the bypass pipe are in use Control means for switching to a non-use state. Hereinafter, the means for reheating will be described in detail with reference to FIGS. 2 to 5, the hot water storage tank 12 shown in FIG. 1 is not shown and is simply indicated as “heat source unit 11”.

  As shown in FIG. 2, the above-described water supply pipe D is provided with an electric shut-off valve SVA and a check valve V1 on the downstream side of the water supply header 8, and the water is supplied only when the shut-off valve SVA is open. It is sent to the header 8 and supplied to the bottom of each heat storage tank 5.

  The water supply pipe D has a branch part p1 on the upstream side of the shutoff valve SVA, and the bypass pipe 20 branches from the branch part p1. The bypass pipe 20 bypasses the heat storage tank 5 and merges with the primary hot water pipe 10 from the water supply return header 9 at the branch portion p2. A shutoff valve SVD and a check valve V2 are provided between the branch part p1 and the branch part p2 of the bypass pipe 20. The primary hot water pipe 10 includes a shut-off valve SVE and a check valve V3 upstream of the branch part p2, and is connected to the water supply side of the heat source unit 11 through the branch part p2. In addition, since the flow of the warm water of the primary hot water piping 10 is controlled by the presence or absence of the water pressure from the tap water and the presence or absence of the hot water from the hot water discharge section 13, the shutoff valve SVE can be omitted.

  Furthermore, the water supply pipe D has a branch part p3 downstream from the shutoff valve SVA, and the branch pipe 16 branched at the branch part p3 joins the hot water supply return pipe 15 and the branch part p4. ing. Between the branch part p3 and the branch part p4 of the branch pipe 16, a shutoff valve SVB and a check valve V4 are arranged. A branch portion p4 (merging portion) between the branch pipe 16 and the hot water supply return pipe 15 is connected to the primary hot water pipe 10 via the circulation pump 30.

  A branch portion p5 is provided at a location near the heat source device 11 of the hot water supply pipe 14, and a return branch pipe 17 is branched from the branch portion p5. The other end of the return branch pipe 17 joins the primary hot water pipe 10 at a branch portion p6 adjacent to the water supply return header 9. The return branch pipe 17 is provided with a shut-off valve SVC and a check valve V5.

  The hot water supply system A according to the present invention has the above-described piping configuration. During normal operation, the shutoff valves SVA and SVE are opened, and the shutoff valves SVB, SVC and SVD are closed as shown in FIG. . In this state, the water supply from the water supply pipe D passes through the shut-off valve SVA, passes through the water supply header 8 and the water supply pipe 6, and is sent to each heat storage tank 5. Therefore, heat is exchanged with a heat medium from the solar heat collecting section, and the temperature is raised to an appropriate temperature to become primary hot water. The primary hot water enters the primary hot water discharge pipe 7 from the upper part of each heat storage tank 5, passes through the water supply return header 9, the primary hot water pipe 10, the shutoff valve SVE, and the check valve V3, and is a secondary heat source. After flowing into the heat source machine 11 and being heated to a required temperature there, it is used as hot water in the hot water outlet 13 through the hot water supply pipe 14, and the remaining secondary hot water is passed through the hot water supply return pipe 15 to the heat source machine 11 side (FIG. 1). In the example shown in (2), it is returned to the hot water storage tank 12).

  During this normal operation, as described above, the shutoff valves SVB, SVC, SVD are closed, and hot water does not flow through the bypass pipe 20, the branch pipe 16, and the return branch pipe 17.

  When the temperature of the hot water in the heat storage tank 5 is, for example, less than 60 ° C. and there is no evidence sent to the heat source unit 11 for a long time, the hot water in the heat storage tank 5 is contaminated by the growth of bacteria. There is a fear. In order to avoid this, it is necessary to reheat the hot water in the heat storage tank 5 to a predetermined temperature of, for example, 60 ° C. or higher. FIG. 3 shows the state of the shutoff valve and the flow of hot water during the reheating operation. As shown in the figure, during the reheating operation, the shutoff valves SVA and SVE are closed and the shutoff valves SVB, SVC and SVD are opened.

  In this state, the water supply from the water supply pipe D does not flow to the heat storage tank 5 side, but flows from the branch part p1 to the bypass pipe 20 side. The inflowing water is heated by the heat source unit 11 through the primary hot water pipe 10 from the branching part p <b> 2 to become secondary hot water, and is sent to the hot water outlet 13 through the hot water supply pipe 14. Therefore, even during the reheating operation, the use of hot water on the hot water supply facility C side is performed without any trouble.

  On the other hand, the hot water in each heat storage tank 5 (hot water that needs reheating) is configured such that the shutoff valve SVB is open and the shutoff valve SVA is closed, so that the water supply pipe 6 and the water supply header 8 are provided from the lower part of each heat storage tank 5. And flows into the branch pipe 16 from the branch portion p3. When the shut-off valve SVE is attached, the shut-off valve SVE is closed. The hot water that has flowed in flows through the shutoff valve SVB and check valve V4, flows into the hot water supply return pipe 15 from the branch portion p4, joins with the feed water flowing from the bypass pipe 20 by the circulation pump 30, and then heat source The secondary hot water is sent to the machine 11 and reheated to a temperature of 60 ° C. or higher, for example.

  A portion of the secondary hot water that has flowed out of the heat source unit 11 is diverted at the branch part p5 and flows into the return branch pipe 17, passes through the shut-off valve SVC and the check valve V5, and then reaches the primary hot water from the branch part p6. It flows into the pipe 10. The heated hot water flowing into the primary hot water pipe 10 is returned from the upper part of the heat storage tank 5 to each heat storage tank 5 through the primary hot water discharge pipe 7 from the feed water return header 9. The above-described reheating operation operation is continued until the hot water in each heat storage tank 5 reaches a predetermined temperature. When the required reheating operation is completed, the respective shut-off valves are returned to normal operation by switching the shut-off valves SVA and SVE to open and the shut-off valves SVB, SVC and SVD to closed.

  Although not shown in the figure, during the reheating operation, the hot water in each heat storage tank 5 is extracted from the primary hot water pipe 10 side and reheated by the heat source unit 11, and then the shut-off valve SVA of the water supply pipe D and the water supply flow go out. Even if it introduce | transduces in the water supply piping D between the headers 8, the reheating of the warm water in each heat storage tank 5 is possible. However, in this aspect, since hot water is extracted from the upper part of the heat storage tank 5 and reheated hot water is supplied from the lower part of the heat storage tank, compared with the embodiment described based on FIG. It takes a long time for the hot water temperature to rise to a predetermined temperature.

  When the above-described reheating operation is performed and when the reheat operation is performed are arbitrary, and may be appropriately performed when the side using the hot water supply system requires. However, it is necessary for the control means provided in the hot water supply system to automatically perform the reheating operation when a certain condition is reached, to prevent the occurrence of contamination due to omission and to be necessary for the reheating operation. It is desirable because energy can be suppressed.

  In general, contamination of water due to bacterial growth tends to occur when left for a long time under a temperature condition of, for example, less than 60 ° C. In the hot water supply system according to the present invention, even when the hot water in the heat storage tank 5 of the solar heat recovery unit B is not maintained at 60 ° C. or higher due to the amount of heat collected in the solar heat collection unit 1, the hot water in the heat storage tank 5 is frequently used. If the heat storage tank 5 is in an environment where it is replaced by new water supply from the water supply pipe D, bacteria will not grow in the heat storage tank 5. Therefore, in the hot water supply system according to the present invention, the means for measuring the temperature of the hot water in the heat storage tank 5 and the primary hot water in the heat storage unit 5 are supplied to the secondary heat source (heat source machine 11) side more than a certain number of times within a certain time. It is a very desirable aspect to include a hot water usage detecting means for detecting that the operation has not been performed. Then, the control means 50 installed in the hot water supply system A measures that the temperature measuring means continuously keeps the temperature of the hot water in the heat storage section 5 for a certain period of time or less, and the means for detecting the use of hot water When it is detected that the primary hot water in the heat storage section 5 has not been supplied to the secondary heat source (heat source unit 11) more than a certain number of times within a certain time, the reheating operation state described above from the normal operation state described above By performing the switching operation of each of the shut-off valves SVA to SVE as described above, it is possible to operate the hot water supply system in a state where there is no contamination.

  As a means for this, the hot water supply system A includes a thermometer TEW1a and a flow meter (not shown) in the water supply return header 9, or in the vicinity of the upstream side of the water supply return header 9 or in the vicinity of the downstream side of the water supply return header 9. And a control means 50 for processing information therefrom. And the control means 50 described above when the temperature measurement value of the thermometer TEW1a continues below the reheating operation start set temperature which is, for example, 60 ° C. and does not detect that the flowmeter has flowed more than the target water amount. Switching operation of each shut-off valve SVA to SVE is performed from the state of FIG. 2 to the state of FIG.

  Providing both a thermometer and a flow meter results in an increase in the number of parts, which makes assembly difficult and increases the cost. In order to avoid this, in the preferred embodiment of the hot water supply system A according to the present invention, the flow meter is abolished, and both temperature measurement and determination of the presence or absence of water flow are performed only by the thermometer TEW1a. That is, the state in which the thermometer TEW1a rises to a certain temperature or more means that the primary hot water in the heat storage unit 5 has been heated to a certain temperature by recovering heat from the solar heat collecting unit 1, If this occurs a certain number of times within a certain time, the hot water stored in the heat storage section 5 flows out and is surely replaced with new water. Therefore, when satisfy | filling this condition, it is not necessary to reheat the warm water in the thermal storage part 5. FIG.

Specifically, the control means 50 monitors whether or not the temperature measurement value of the thermometer TEW1a continues below the reheating operation start set temperature, and at the same time monitors the temperature rise of the sensitive part temperature, It is monitored whether or not the water flow monitoring set temperature (for example, plus 3 to 4 ° C.) or higher is reached within the rise monitoring set time (for example, 100 hours). However, it is determined that there is a predetermined water flow, and switching to the reheating operation is not performed. Switch to reheating operation only when the specified number of times has not been reached and the water flow rise monitoring set time has been exceeded.

  As an example of the control, for example, a flag is raised when a temperature rise occurs, and the flag interval time between the flags and the number of flags “1” are recorded. When the total number of flags reaches the preset value for the number of times of water flow monitoring, if the total time of the flag interval time is equal to or longer than the reheating operation start setting time, the reheating operation is started. If the total time of the flag interval time is less than the reheating operation start set time, the first recorded flag interval time and the number of flags “1” are deleted. Further, when the sensor temperature of the thermometer TEW1a becomes equal to or higher than the reheating operation set temperature during monitoring, the recorded flag interval time and the number of flags are deleted. Further, monitoring is suspended during reheating, and the flag interval time and the number of flags recorded after the end of reheating are deleted.

  When the thermometer TEW1a described above (and the flow meter in the case of use) is installed in the feed water return header 9 or in the vicinity of the downstream side of the feed water return header 9, the installation of one thermometer TEW1a has the intended purpose. Can be achieved. However, when the temperature in each heat recovery unit is not uniform, it is unavoidable that inconveniences such as misjudgment occur.

  A thermometer TEW1a is installed in the primary hot water discharge pipe 7 from each heat storage tank 5, and based on the information from each thermometer TEW1a, it is determined whether the control means 50 performs the reheating operation. It may be. However, in this case, as many thermometers TEW1a as the number of heat recovery units B are required, and the information processing mechanism becomes complicated. Therefore, it becomes high cost.

  The present inventors conducted experiments and research for obtaining data for starting the reheating operation at a level that does not hinder practical use with a smaller number of thermometers TEW1a. Thereby, the thermometer TEW1a is arranged in the primary hot water discharge pipe 7 with the shortest pipe length of the primary hot water discharge pipe 7 from each heat storage section 5 to the feed water return header 9, and based on information from there It has been found that even if the control means 50 performs the switching operation of each shut-off valve, the switching to the reheating operation can be performed at a level that does not impede practically. The reason for this is that in the hot water supply system A having two or more heat recovery units B, depending on the length of the pipe length from each heat storage tank 5 to the feed water return header 9 in relation to the pipe resistance, the feed water return The flow rate of warm water flowing into the header 9 changes, and in the heat recovery unit having the longest pipe line length, the flow rate flowing into the feed water return header 9 from the heat storage unit 5 is minimized. Therefore, in the heat storage tank 5 of the heat recovery unit with the longest pipe length, the primary hot water is the highest and lower in the heat storage tank 5 of the heat recovery unit with the shortest pipe length. For this reason, switching to the reheating operation based on temperature information on the lower side is considered to be the safest side.

  FIG. 6 shows a case of the hot water supply system A provided with the three heat recovery units B shown in FIG. 1, and the heat storage tanks 5-1, 5-2, 5- 3 when the pipe length of the primary hot water discharge pipe 7 is longer in the order of 7-1, 7-2, 7-3, the thermometer is connected to the primary hot water discharge pipe 7-3 from the shortest heat storage tank 5-3. By providing the TEW 1a, the intended purpose can be achieved. In this aspect, since it is possible to switch to the reheating operation with one thermometer TEW1a, it is possible to construct the hot water supply system A at a lower cost.

  In the figure, a thermometer TEW1b arranged in the vicinity of the water supply header 8 is used to determine whether or not the heat storage tank 5 has been reheated at a predetermined temperature. As shown in FIG. It prepares for the water supply piping 6-1 from the longest heat storage tank 5-1. As described above, the longer the pipe length is, the smaller the flow rate is, and the reheating becomes the slowest among the three heat recovery units. This is because it is considered to be a safe side.

  As shown in FIG. 4, the hot water supply system A according to the present invention is operated by closing the shutoff valves SVA, SVB, SVC, and the SVE when attached, and opening the shutoff valve SVD, thereby providing a high temperature hot water prevention function. be able to. That is, during the normal operation shown in FIG. 2, when the thermometer TEW1a measures a temperature equal to or higher than the set temperature, the control means 50 opens and shuts off the shutoff valve SVA shown in FIG. The valves SVB, SVC, SVD are switched from the closed state to the above-described shut-off valves SVA, SVB, SVC, SVE when attached, and the shut-off valve SVD are opened. Since the shutoff valve SVA is closed, the water supply flows into the bypass pipe 20 from the branch part p1 and does not flow to the heat storage tank 5 side, so the shutoff valve SVE may be opened.

  The feed water that has flowed into the bypass pipe 20 passes through the shutoff valve SVD and the check valve V2 and reaches the branch portion p2. On the other hand, since the primary hot water in the heat storage tank 5 that has become hotter than the set value does not flow due to the water pressure of the water supply pipe D, it is possible to avoid unexpectedly high temperature hot water from the hot water outlet 13.

  Further, as shown in FIG. 5, the hot water supply system A according to the present invention is provided with an inlet pressure gauge F1 upstream of the branch part p1 of the water supply pipe D, and the branch part p2 of the primary hot water pipe 10 and the heat source device. 11 is provided with an outlet pressure gauge F2, and the control means 50 detects the pressure difference between the two and operates the shut-off valve to prevent the pressure drop caused by the change in the amount of water supply or hot water. In addition, a function for preventing an excessive flow rate can be provided.

  That is, when the amount of water supply from the water supply pipe D changes greatly, the differential pressure between the water supply pipe D and the hot water supply pipe 14 exceeds the set value. When the feed water pressure is high, such pressure fluctuation indicates that the flow rate flowing through the feed water pipe 6 and the primary hot water discharge pipe 7 to the heat storage etc. 5 greatly exceeds the design value. Usually, pipes in the heat storage tank, the water supply pipe 6 and the primary hot water discharge pipe 7 are smaller than the primary hot water pipe 10 and the hot water supply pipe 14, and an excessive flow of water or hot water is used there. Flow can cause erosion. Also, unexpected pressure loss occurs.

  In the hot water supply system A shown in FIG. 5, during the normal operation, the control means 50 measures the differential pressure between the inlet pressure gauge F1 and the outlet pressure gauge F2, and closes when the differential pressure exceeds a set value. Open the shut-off valve SVD. Thereby, the water supply from the water supply pipe D flows into the bypass pipe 20 side from the branch point p1, the differential pressure is reduced, and the amount of water flowing through the water supply pipe 6 and the primary hot water discharge pipe 7 is reduced. Thereby, unnecessary pressure loss and erosion can be effectively prevented.

  As described above, in the hot water supply system A according to the present invention, by providing the bypass pipe 20 and controlling the open / close state of the shut-off valves SVA to SVE, the hot water in the heat storage section 5 can be prevented from being contaminated and at the same time expected. High temperature hot water that does not flow out can be prevented from coming out of the hot water supply section 3, and the water pressure can be increased by installing the inlet pressure F1 and outlet pressure gauge F2 and using the differential pressure information. It is possible to appropriately cope with a pressure drop caused by a change.

Further, as one use mode of the hot water supply system according to the present invention, when the temperature measured by the thermometer TEW1b disposed in the vicinity of the feed water header 8 detects a temperature of 2 ° C. or less, for example, the reheating piping system By switching the bypass pipe from the non-use state to the use state, it effectively functions to prevent the hot water supply system from freezing.

A ... Hot water supply system,
B ... Heat recovery unit,
C ... Hot water supply equipment,
D: Water supply piping,
1 ... (solar heat) heat collection part as a primary heat source,
5. Heat storage part (heat storage tank)
6 ... Water supply piping,
7 ... Primary hot water discharge pipe,
8 ... Water supply header,
9 ... Return water header,
10 ... Primary hot water piping,
11 ... Gas heat source machine as a secondary heat source 12 ... Hot water storage tank,
13 ... Hot springs,
14 ... Hot water supply piping,
15 ... Hot water supply return piping,
20 ... Bypass piping,
50. Control means,
SVA to SVE: Electric shut-off valve,
V1 to V5 ... check valves,
p1 to p6 ... branch portion of the pipe,
TEW1a, TEW1b ... thermometer,
F1, F2 ... Pressure gauge.

Claims (8)

A heat recovery unit comprising a primary side heat source and a heat storage unit that recovers heat from the primary side heat source, a secondary side heat source that heats primary hot water preheated by the heat storage unit of the heat recovery unit, and the secondary A hot water supply system comprising a hot water supply facility for supplying secondary hot water heated by a side heat source to a hot water use place,
The hot water supply system further includes a reheating piping system for heating the hot water in the heat storage unit with a secondary heat source of the hot water supply facility and then returning the hot water in the heat storage unit to the heat storage unit again to reheat the hot water in the heat storage unit of the heat recovery unit. A bypass pipe for directly connecting a water supply pipe to the heat storage section and a primary hot water pipe from the heat storage section to a secondary heat source during reheating, and the reheating pipe system and the bypass pipe are in use A control means for switching to a non-use state ,
The control means for switching the reheat piping system and the bypass pipe between the use state and the non-use state includes a temperature measurement means for measuring the temperature of the hot water in the heat storage section and the primary hot water in the heat storage section within the predetermined time as the secondary heat source. A hot water use detecting means for detecting that the hot water has not been supplied more than a certain number of times, and the temperature measuring means measures that the temperature of the hot water in the heat storage section continues for a certain time or more and is below a certain temperature, and uses the hot water. When the detection means detects that the primary hot water in the heat storage unit has not been supplied to the secondary heat source more than a certain number of times within the predetermined time, the reheating piping system and the bypass piping are switched to a use state. A hot water supply system that is characteristic.   The hot water supply system according to claim 1, wherein the primary heat source is heat from exhaust gas from a solar heat collector or a cogeneration system.   Two or more of the heat recovery units are provided, and primary hot water from each of the heat recovery units is supplied to the secondary heat source provided in the hot water supply facility in a state of being joined together in a header. Item 3. A hot water supply system according to item 1 or 2. A thermometer is provided in a pipe on the downstream side of the heat storage unit, and the thermometer is used to measure whether or not the primary hot water in the heat storage unit has been supplied to the secondary heat source more than a certain number of times within the predetermined time. The hot water supply system according to any one of claims 1 to 3, wherein the hot water supply system is performed by measuring the number of times the temperature has risen above the temperature. The hot water supply system according to claim 4 , wherein the thermometer is also used for measuring that the temperature of the hot water in the heat storage unit continues for a predetermined time or longer and is equal to or lower than a predetermined temperature. The temperature measuring gauge, the pipe length from the heat storage unit to the header, according to claim 5, characterized in that disposed in the conduit near the heat recovery unit with a shortest line length Hot water system. A hot water supply system according to any one of claims 1 to 6, wherein further comprising a delivery side temperature measuring meter hot water outlet side of the heat storage unit, the control unit, the output-side temperature measuring meter When the measured value is equal to or higher than a certain temperature, the bypass pipe is opened to stop water supply to the heat storage unit. A hot water supply system according to any one of claims 1 to 7 from the heat storage unit and the inlet side pressure gauge on the upstream side of the bypass pipe in the water supply conduit to the heat storage unit to the secondary heat source An outlet pressure gauge downstream of the bypass conduit in the primary hot water conduit, further comprising a differential pressure detecting means for measuring a differential pressure between the outlet pressure and the inlet pressure, and the control means includes the When the measured value of the differential pressure detection means exceeds a certain value, the water supply system is characterized in that the bypass pipe is opened and a part of the water supply is supplied directly to the primary hot water pipe.

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