JP6033321B2 - Hot water system - Google Patents

Description

  The present invention relates to a hot water supply system capable of instant hot water at a hot water outlet terminal such as a faucet or a shower.

  In general, a hot water supply apparatus using a heat pump includes a refrigeration cycle in which a compressor, a radiator, an expansion valve, and a heat absorber are sequentially connected by a refrigerant pipe. And heat exchange is performed between refrigerant | coolants, such as a carbon dioxide, and water, and hot water is produced | generated. Hot water generated by the hot water supply device is sent from a hot water storage tank to a hot water outlet terminal such as a faucet or shower through a hot water supply pipe.

  In business use such as a commercial facility such as a hotel, the hot water supply piping becomes very long due to the characteristics of the facility. In view of this, a hot water supply system capable of immediately discharging hot water has been proposed (see, for example, Patent Documents 1 and 2). In Patent Documents 1 and 2, a hot water supply pipe is connected to the hot water storage tank, and a hot water outlet terminal and a circulation pipe are branched and connected to the hot water supply pipe. Hot water flowing through the hot water supply pipe is returned to the hot water storage tank through the circulation pipe. Since the hot water circulates in the hot water supply pipe and the circulation pipe, the hot water stored in the hot water storage tank can be immediately used at the hot water outlet terminal.

Japanese Patent No. 4943258 JP 2012-32078 A

  However, in the hot water supply systems of Patent Documents 1 and 2, a circulation pump is disposed on the circulation pipe side that is returned to the hot water storage tank after branching from the hot water supply pipe to the hot water outlet terminal. For this reason, when the water distribution pipe (water supply) to the facility where the hot water supply system is installed is cut off due to a power failure or the like, the water staying in the water distribution pipe is sucked through the mixing plug by the operation of the circulation pump. There is a problem that the pressure in the water distribution pipe fluctuates.

  The present invention has been made in order to solve the above-described problems, and an object of the present invention is to provide a hot water supply system capable of suppressing pressure fluctuations in a water distribution pipe while enabling instant hot water.

A hot water supply system according to the present invention is connected to a hot water storage tank for storing hot water, a hot water supply pipe for supplying hot water in the hot water storage tank to a hot water outlet terminal, a hot water supply pipe and a hot water storage tank, and hot water flowing through the hot water supply pipe to the hot water storage tank. The return piping and the hot water supply pipe are provided at a position where the distance to the hot water storage tank is shorter than the distance to the hot water terminal, and the hot water in the hot water storage tank is sucked and discharged to the hot water terminal side and the circulation pipe side. Water is supplied to the circulation pump, the mixing tap connected between the hot water supply pipe and the hot water terminal, the water distribution pipe for supplying water to the mixing tap, the check valve provided in the water distribution pipe, and the hot water storage tank. a water supply pipe for, provided in the water supply pipe, in which pressure reduction value with a variable pressure reducer, a.

  According to the hot water supply system according to the present invention, since the circulation pump is arranged between the hot water terminal and the circulation pump applies a pressure for discharging hot water to the hot water terminal, there is a case where water is shut off. However, the circulation pump does not suck water in the water distribution pipe connected to the hot water outlet terminal, and it is possible to reliably prevent pressure fluctuations in the water distribution pipe while enabling instant hot water.

It is a schematic diagram which shows Embodiment 1 of the hot water supply system of this invention. It is a graph which shows the pressure distribution in the circulation circuit in Embodiment 1 of this invention. It is a schematic diagram which shows an example of the conventional hot water supply system. It is a graph which shows the pressure fluctuation in the distribution pipe at the time of the water stop in the hot water supply system of FIG. 1, and the hot water supply system of FIG.

Embodiment 1. FIG.
FIG. 1 is a schematic diagram showing Embodiment 1 of the hot water supply system of the present invention. A hot water supply system 100 in FIG. 1 includes a hot water supply device 1, a hot water storage tank 2, a hot water supply pipe 11, a circulation pump 12, a circulation pipe 14, and the like. The hot water supply device 1 is composed of, for example, a heat pump type hot water supply device using carbon dioxide as a refrigerant, and is connected to the hot water storage tank 2 by connection pipes 3a and 3b. And the hot water supply apparatus 1 heats the low water temperature water of the lower part in the hot water storage tank 2 supplied from the connection piping 3a, and sends the heated hot water to the hot water storage tank 2 via the connection piping 3b.

  The hot water storage tank 2 stores hot water supplied by the hot water supply device 1 and is connected to the hot water supply device 1 by connection pipes 3a and 3b. Furthermore, a lower part of the hot water storage tank 2 is connected to a water distribution pipe (water pipe) 41 through a water supply pipe 4, a check valve 6, and a pressure reducer 7. For example, when hot water is consumed at the hot water terminal 22 and the amount of hot water stored in the hot water storage tank 2 becomes a predetermined amount or less, water is supplied from the water distribution pipe 41 through the water supply pipe 4, the check valve 6, and the pressure reducer 7. The hot water storage tank 2 is supplied.

  Furthermore, when the hot water in the hot water storage tank 2 becomes a predetermined temperature or less, low temperature water is sent from the lower part of the hot water storage tank 2 to the hot water supply device 1 through the connection pipe 3a. And the hot hot water heated in the hot-water supply apparatus 1 is again supplied to the hot water storage tank 2 via the connection piping 3b. Thus, the hot water supply device 1 and the hot water storage tank 2 constitute a heat source circuit that circulates low-temperature water and high-temperature water.

  In particular, a predetermined set value is preset in the decompressor 7, and when the pressure of water discharged from the decompressor 7 becomes lower than the set value, the valve inside the decompressor 7 is operated in the opening direction. On the other hand, when the pressure exceeds the set value, the valve inside the decompressor 7 is operated in the closing direction. The set value of the decompressor 7 can be varied from the outside. If it is desired to save water, if the set value is lowered, the amount of water supplied to the hot water storage tank 2 can be reduced to save water. Note that, when the set value is small, the pressure in the hot water storage tank 2 decreases, but a necessary and sufficient pressure for supplying the hot water terminal 22 by the circulation pump 12 can be obtained. For this reason, hot water can be stably supplied to the hot water terminal 22.

  When hot water is used at the hot water terminal 22, the internal pressure in the hot water storage tank 2 decreases and the pressure on the discharge side of the decompressor 7 decreases. Then, a difference arises between the internal pressure of the water distribution pipe 41 and the pressure on the discharge part side (hot water storage tank side) of the decompressor 7. Also in this case, the decompressor 7 opens the internal valve so that the pressure of the discharge part becomes a set value. Then, water is supplied from the water distribution pipe 41 and the water supply pipe 4 to increase the pressure on the discharge side of the decompressor 7, and when the pressure becomes a set value or more, the valve inside the decompressor 7 is closed and the hot water storage tank 2 is connected. Water supply is stopped.

  The hot water supply pipe 11 is attached to the upper part of the hot water storage tank 2 and supplies hot water in the hot water storage tank 2 to the hot water outlet terminal 22. The hot water supply pipe 11 is provided with a circulation pump 12, and the circulation pump 12 sucks hot water from the hot water storage tank 2 and discharges it to the hot water outlet terminal 22 side through the hot water supply pipe 11. The operation of the circulation pump 12 is controlled by the circulation control means 33.

  A check valve 13 is connected to the circulation pump 12 in parallel. The check valve 13 allows hot water to pass only from the hot water storage tank 2 side to the hot water terminal 22 side. When the circulation pump 12 is stopped or malfunctioning or when a small capacity pump is selected to suppress pump power, hot water passes through the check valve 13 due to the internal pressure of the hot water storage tank 2 and is supplied to the hot water terminal 22. Will be.

  Here, the circulation pump 12 and the check valve 13 are installed such that the distance to the hot water storage tank 2 is shorter than the distance to the hot water terminal 22. In particular, the circulation pump 12 and the check valve 13 are preferably provided in the vicinity of the hot water storage tank 2. That is, the pressure of the suction portion 12 a of the circulation pump 12 is reduced in proportion to the piping distance from the hot water storage tank 2. If bubbles are generated by this decompression (cavitation), the bubbles may cause the circulation pump 12 to fail or the life of the pump to be reduced. Therefore, by installing the suction portion 12a of the circulation pump 12 on the side close to the hot water storage tank 2 of the hot water supply pipe 11, it is possible to prevent the circulation pump 12 from being broken.

  A hot water supply terminal 22 and a circulation pipe 14 are branched and connected to the hot water supply pipe 11. The hot water terminal 22 is composed of a shower / curan, a faucet, and the like, and is connected to the hot water supply pipe 11 via the mixing tap 21. The mixing plug 21 is connected to the oil supply pipe 11, and is connected to the water distribution pipe 41 through the check valve 8, the decompressor 9, and the water supply pipe 5. In the mixing tap 21, hot water supplied from the hot water supply pipe 11 and water supplied from the water distribution pipe 41 are mixed, and hot water having an optimal temperature is provided from the hot water outlet terminal 22. As described above, in the hot water supply system 100, the hot water supply pipe 11, the circulation pump 12, the check valve 13, the mixing tap 21, and the hot water terminal 22 constitute a hot water supply circuit.

  The circulation pipe 14 branches from the hot water supply pipe 11 and is connected to the lower part of the hot water storage tank 2, and the hot water discharged from the circulation pump 12 is returned to the hot water storage tank 2 through the circulation pipe 14. Thus, in the hot water supply system 100, the hot water storage tank 2, the hot water supply pipe 11, the circulation pump 12, the check valve 13, and the circulation pipe 14 constitute a circulation circuit 10 that returns hot water to the center or the lower part of the hot water storage tank 2. Yes.

  The hot water supply system 100 further includes a pressure detection unit 31, a temperature detection unit 32, and a circulation control unit 33. The pressure detection unit 31 detects the pressure of hot water flowing in the circulation circuit 10 and is installed on the hot water supply pipe 11, for example. The circulation control means 33 operates the circulation pump 12 when the pressure P detected by the pressure detection unit 31 becomes equal to or lower than a preset set pressure Pref. As a result, large-capacity hot water can be supplied without increasing the internal pressure in the hot water storage tank 2 by the operation of the circulation pump 12. When the pressure P is higher than the set pressure, the circulation control means 33 stops the circulation pump 12.

  The temperature detector 32 detects the temperature T of hot water circulating in the circulation circuit 10. Then, the circulation control means 33 stops the operation of the circulation pump 12 when the temperature T detected by the temperature detection unit 32 becomes equal to or higher than a preset temperature Tref. Thereby, it is possible to provide a system that can prevent wasteful heat dissipation from hot and cold water by circulating in the circulation circuit 10 and can efficiently realize instant hot water that immediately provides hot water having a high temperature.

  FIG. 2 is a graph showing the pressure at each position in the hot water supply system 100 of FIG. 1, and the flow of hot water in the hot water supply system 100 will be described with reference to FIGS. 1 and 2 and FIG. As shown in FIG. 2, it is assumed that the internal pressure of the hot water storage tank 2 is a predetermined pressure, and the circulation pump 12 is operated under the control of the circulation control means 33 described above. First, hot water is sucked into the suction part 12 a of the circulation pump 12 from the upper part of the hot water storage tank 2. At this time, the pressure is reduced from the hot water storage tank 2 in proportion to the piping length of the circulation pump 12.

  The hot water drawn from the suction part 12a of the circulation pump 12 is discharged from the discharge part 12b of the circulation pump 12 toward the hot water terminal 22 side. At this time, hot water is also discharged from the check valve 13. At this time, the internal pressure in the hot water supply pipe 11 is increased by the circulation pump 12. Thereafter, the hot water flowing through the hot water supply pipe 11 is branched into the hot water terminal 22 side and the circulation pipe 14 side. The amount of hot water branched to the circulation pipe 14 side depends on the amount of hot water used at the hot water terminal 22. On the other hand, the hot water flowing through the circulation pipe 14 is returned to the hot water storage tank 2 again.

  Thus, by providing the circulation pump 12 on the hot water supply pipe 11 side, even if the water distribution pipe 41 is shut off due to the stoppage of the pressurization pump 40 or the like, the pressure in the water distribution pipe 41 is prevented from fluctuating. be able to. That is, in the conventional hot water supply system 200 as shown in FIG. 3, the circulation pump 212 is arranged on the circulation pipe 14 side. Accordingly, the circulation pump 212 sucks hot water from the hot water supply pipe 11 and the suction portion 212a on the side of the hot water terminal 22. Here, when the above-described water break occurs, the circulation pump 212 not only sucks the water in the water supply pipe 5 through the mixing plug 21 but also the water in the water distribution pipe 41 through the check valve 8. I will suck it. For this reason, there exists a problem that the pressure fluctuation of not only the water supply piping 5 but the water distribution pipe 41 is produced.

  FIG. 4 is a graph showing pressure fluctuations in the water distribution pipe 41 at the time of water interruption in the hot water supply system 100 of FIG. 1 and the conventional hot water supply system 200 of FIG. In FIG. 4, the inside of the water distribution pipe 41 is always filled with water by the pressurization pump 40 installed in the upstream part of the water distribution pipe 41, and the high pressure state is hold | maintained. Then, the water in the water distribution pipe 41 is supplied to the hot water terminal 22 through the check valve 8, the decompressor 9, and the water supply pipe 5. Here, in the case where water shutoff occurs, for example, when the power supply to the pressurizing pump 40 is cut off, if the circulating pumps 12 and 212 are not operating as shown in FIG. To maintain.

  On the other hand, when the circulation pumps 12 and 212 are operated at the time of water interruption, water is supplied to the hot water terminal 22 only with the residual pressure of the feed water pipe 5, and the residual pressure of the feed water pipe 5 becomes smaller as the water is used at the hot water terminal 22. At this time, in the conventional hot water supply system 200 as shown in FIG. 3, the circulation pump 212 is connected not only to the water in the water supply pipe 5 but also to the mixing plug 21 because the suction part 212a is connected to the hot water terminal 22 side. Water in the water distribution pipe 41 is also sucked through the stop valve 8 and the decompressor 9. As a result, the pressure fluctuation in the water distribution pipe 41 occurs more than the pressure drop in the water distribution pipe 41 due to a power failure.

  On the other hand, in the hot water supply system 100 of FIG. 1, a hot water outlet terminal 22 is connected to the discharge unit 12 b side of the circulation pump 12. Accordingly, when the operation of the pressurizing pump 40 is stopped and the circulation pump 12 is operated in a state where water is cut off, the hot water discharged from the circulation pump 12 is discharged from the hot water supply pipe 11 to the water supply pipe 5 through the mixing plug 21. Will be applied. Here, since the check pipe 8 is provided in the water supply pipe 5, the water pressurized by the circulation pump 12 is blocked by the check valve 8. Therefore, in the hot water supply system 100 in which hot water is circulated in the circulation circuit 10 using the circulation pump 12 so that the hot water in the hot water supply circuit is kept high and instant hot water is possible, the pressure fluctuation of the water distribution pipe 41 is kept small. Can do. That is, since the circulation pump 12 is disposed in the hot water supply pipe 11 on the upstream side of the hot water terminal 22, the pressure fluctuation of the water supply pipe 5 can be kept small even when the water supply is interrupted due to a power failure or the like.

  When a large volume of hot water is used at the hot water terminal 22, the pressure on the suction side of the circulation pump 12 is reduced in proportion to the piping distance from the hot water storage tank 2. Since bubbles are generated by the decompression, the circulation pump 12 can be installed closer to the hot water storage tank 2 in the hot water supply pipe 11 to prevent the pump from being damaged by the bubbles.

  Furthermore, in the conventional hot water supply system 200 of FIG. 3, in order to prevent this cavitation, the internal pressure of the hot water supply pipe 11 needs to be increased. Furthermore, in order to supply a large volume of hot water, the internal pressure in the hot water storage tank 2 must be increased, and it is necessary to increase the strength of the hot water storage tank 2, which increases the cost. On the other hand, as shown in FIG. 1, by disposing the circulation pump 12 in the vicinity of the hot water storage tank 2, even if the pressure in the hot water storage tank 2 is set low, the suction portion 12a of the circulation pump 12 does not become negative pressure, Cavitation can be prevented and hot water can be circulated stably.

  Moreover, the pressure detection part 31 is provided in the discharge part 12b side of the circulation pump 12, and when the pressure detected by the pressure detection part 31 becomes below a preset set value, the circulation control means 33 operates the circulation pump 12. Thus, a large volume of hot water can be supplied without increasing the internal pressure in the hot water storage tank 2.

  Further, by controlling the operation of the circulation pump 12 using the temperature detected by the temperature detection unit 32, wasteful heat dissipation from hot water caused by circulation in the circulation circuit 10 is prevented, and hot water having a high temperature is immediately discharged. It is possible to provide a system capable of efficiently realizing the instant hot water provided to.

  Further, by providing the water supply pipe 4 to the hot water storage tank 2 with a pressure reducer 7 that opens and closes an internal valve based on a set value that is variable from the outside, a small amount of hot water can be intentionally supplied (water saving).

  The embodiment of the present invention is not limited to the above embodiment. For example, although FIG. 1 illustrates the case where one hot water storage tank 2 is provided, a plurality of hot water storage tanks 2 may be installed in parallel or in series.

  1 illustrates the case where the circulation pump 12 and the check valve 13 are provided separately from the hot water storage tank 2, the hot water storage tank 2, the circulation pump 12 and the check valve 13 include the hot water storage. It may be provided integrally with the tank 2. Thereby, generation | occurrence | production of the bubble mentioned above can be suppressed, installation work can be facilitated, and the diameter of the pipe connecting the hot water storage tank 2 and the circulation pump 12 can be reduced.

  Further, in FIG. 1, the installation location of the pressure detection unit 31 and the temperature detection unit 32 may be provided in either the hot water supply pipe 11 or the circulation pipe 14 as long as it is in the circulation circuit 10, and is limited to the above embodiment. Not.

  DESCRIPTION OF SYMBOLS 1 Hot water supply apparatus, 2 Hot water storage tank, 3a, 3b Connection piping, 4, 5 Water supply piping, 6 Check valve, 7 Pressure reducing device, 8 Check valve, 9 Pressure reducing device, 10 Circulation circuit, 11 Hot water piping, 12, 212 Circulation Pump, 12a, 212a Suction part, 12b, 212b Discharge part, 13 Check valve, 14 Circulation pipe, 15 Water supply pipe, 21 Mixing tap, 22 Hot water terminal, 31 Pressure detection part, 32 Temperature detection part, 33 Circulation control means, 40 Pressure pump, 41 Water distribution pipe, 100, 200 Hot water supply system, P pressure, Pref set pressure, T temperature, Tref set temperature.

Claims (4)

A hot water storage tank for storing hot water,
A hot water supply pipe for supplying the hot water in the hot water storage tank to a hot spring terminal;
A circulation pipe connected to the hot water supply pipe and the hot water storage tank and returning the hot water flowing through the hot water supply pipe to the hot water storage tank;
The hot water supply pipe is provided at a position where the distance to the hot water storage tank is shorter than the distance to the hot water terminal, and the hot water in the hot water storage tank is sucked into the hot water terminal side and the circulation pipe side. A circulating pump for discharging,
A mixer tap connected between the hot water supply pipe and the hot water terminal;
A water distribution pipe for supplying water to the mixer tap;
A check valve provided in the water pipe ;
A water supply pipe for supplying water to the hot water storage tank;
A decompressor having a variable decompression value provided in the water supply pipe;
Hot water supply system comprising the.   The hot water supply system according to claim 1, further comprising a check valve connected in parallel to the circulation pump. A pressure detector for detecting the pressure in the circulation pipe;
The hot water supply system according to claim 1, further comprising a circulation control unit that activates the circulation pump when the pressure detected by the pressure detection unit becomes equal to or lower than a preset set pressure. . A temperature detector for detecting the temperature in the circulation pipe;
The circulation control means for stopping the circulation pump when the temperature detected by the temperature detection unit is equal to or higher than a preset temperature, further comprising: The hot water supply system described.

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