JP2005214436A - Heat pump type hot-water supply system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for preventing freezing of a hot-water supply system having a plurality of heat pumps. <P>SOLUTION: This hot-water supply system is composed of the plurality of heat pumps, circulation pumps for circulating water in each heat pump, a freezing sensor for predicting freezing of each heat pump, a control part for controlling each circulation pump, a general control part for controlling each control part on the whole, a hot-water storage tank for storing hot water, a heat pump going passage pipe, a heat pump return passage pipe, a tank going passage pipe, and a tank return passage pipe. This system is provided with a bypass change-over valve for switching a hot-water supply circuit in which water flows in the heat pump going passage pipe, the tank going passage pipe, the hot-water storage tank, the tank return passage pipe, and the heat pump return passage pipe from the heat pump in this order and returns into each heat pump and a bypass circuit in which water comes out of the heat pump, flows in the heat pump going passage pipe, and the heat pump return passage pipe in this order, and returns into each heat pump. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to freeze prevention of a heat pump hot water supply system having a heat pump and a hot water storage tank for storing hot water.

  Conventionally, a heat pump type hot water supply system that heats water with a heat pump and stores it in a hot water storage tank has been used. Here, in order to prevent the circulation pipe connecting the heat pump and the hot water storage tank from freezing when the external temperature decreases, it is usually performed to install a heater in the circulation pipe.

  On the other hand, prevention of freezing by operating a circulation pump to circulate water is disclosed in JP-A-5-272812 (Patent Document 1), Patent 2002-48399 (Patent Document 2) and Patents. It is disclosed in 2002-213821 (patent document 3). As shown in FIG. 4, the heat pump hot water supply system disclosed in these patent documents has a heat pump 1, a circulation pump 2 that circulates water of the heat pump 1, a hot water storage tank 4 that stores hot water, A heat pump outgoing pipe 5 for discharging water from the heat pump 1, a heat pump return pipe 6 for supplying water to the heat pump 1, a tank outgoing pipe 10 for supplying hot water to the hot water storage tank 4, and a tank return pipe 11 for discharging water from the hot water storage tank 4. And have. Further, a water pipe 13 for supplying tap water or the like to the hot water storage tank 4 from the outside and a hot water supply pipe 14 for supplying hot water from the hot water storage tank to the hot water outlet 15 are provided. The heat pump return pipe 6 is provided with a check valve 9, the water pipe 13 is provided with a water tap 16, and the hot water supply pipe 14 is provided with a hot water tap 17.

Here, a bypass switching valve 12 is provided between the heat pump forward piping 5 and the tank forward piping 10 and between the heat pump return piping 6 and the tank return piping 11. Normally, the heat pump 1 and the circulation pump 2 are operated, and the heat pump 1 → the heat pump forward piping 5 → the bypass switching valve 12 → the tank outward piping 10 → the hot water tank 4 → the tank return piping 11 → the bypass switching valve 12 → the heat pump return piping 6 → The water warmed by the heat pump 1 is supplied to the hot water storage tank 4 by circulating water through a hot water supply circuit called the heat pump heat pump 1. In the heat pump type hot water supply system in this state, since water is circulated, freezing does not occur even if the external temperature decreases. However, for example, when the hot water storage tank 4 is full and the operation of the heat pump 1 and the circulation pump 2 is stopped, if the temperature decreases, the heat pump 1, the heat pump forward piping 5 and the heat pump return piping 6 may freeze. Was produced. Therefore, when freezing is predicted by a temperature sensor or the like, the circulation pump 2 is operated, and the bypass switching valve 12 is switched, so that the heat pump 1 → the heat pump forward piping 5 → the bypass switching valve 12 the heat pump return piping 6 → the heat pump. Freezing is prevented by configuring a bypass circuit called a heat pump 1 and circulating water in the bypass circuit. In such a heat pump hot water supply system, freezing can be prevented without providing a heater or the like. Although not shown in FIG. 4, the heat pump hot water supply system disclosed in Patent Documents 1 to 3 includes a heat exchanger between the heat pump 1 and the hot water storage tank 4.
JP-A-5-272812 Japanese Patent No. 2002-48399 Japanese Patent No. 2002-213821

  Recently, hot water storage tanks have been increased in size so that a large amount of hot water can be used. In accordance with this, a plurality of heat pumps are connected in parallel to the hot water storage tank to supply a large amount of hot water to the hot water storage tank. In such a heat pump hot water supply system, when the amount of hot water stored in the hot water storage tank is extremely small, a large amount of hot water is provided in a short time by operating all the heat pumps, while the amount of hot water stored in the hot water storage tank exceeds a certain level. In such a case, energy is saved by operating only some of the heat pumps.

  Here, for the hot water supply system having such a plurality of heat pumps, when the freeze prevention method disclosed in Patent Documents 1 to 3 is used as it is, when only some of the heat pumps are operating, There was a risk that a heat pump that was not operating would freeze.

  This invention is invented in view of the said background art, and is providing the method of preventing freezing about the hot water supply system which has several heat pumps.

  In order to solve the above problems, a heat pump hot water supply system of the present invention includes a plurality of heat pumps, a circulation pump that circulates water of each of the heat pumps, a freezing sensor that predicts freezing of each of the heat pumps, A control unit that controls the circulation pump, a general control unit that controls each of the control units as a whole, a hot water storage tank that stores hot water, a heat pump forward piping for discharging water from the heat pump, and water to the heat pump A heat pump return pipe for supplying water, a tank outgoing pipe for supplying hot water to the hot water storage tank, and a tank return pipe for discharging water from the hot water storage tank. Heat pump forward piping, tank forward piping, hot water storage tank, tank return piping, heat pump A bypass for switching between a hot water supply circuit that passes in the order of the return pipe and returns to each of the heat pump heat pumps, and a bypass circuit that discharges water from the heat pump and passes through the heat pump return path and the heat pump return lines in order of the heat pump and returns to the heat pump. It is characterized by comprising a switching valve.

  The heat pump hot water supply system of the present embodiment includes a control unit that controls each circulation pump and a general control unit that controls each control unit as a whole, and includes a hot water supply circuit and a bypass circuit by a bypass switching valve. Therefore, freezing can be reliably prevented even in a hot water supply system having a plurality of heat pumps.

  The heat pump hot water supply system of this embodiment is demonstrated based on FIGS. As shown in FIG. 1, the heat pump hot water supply system of the present embodiment includes three heat pumps 1 a, 1 b, 1 c, circulation pumps 2 a, 2 b, 2 c built in each heat pump, and each heat pump 1 a, 1b and 1c and controllers 3a, 3b and 3c for controlling the operation of the circulation pumps 2a, 2b and 2c. The heat pumps 1a, 1b, and 1c each have a freezing sensor (not shown) that senses the internal temperature and generates a freezing prediction signal when the temperature falls below a certain temperature. A general control unit 18 that is electrically connected to the control units 3a, 3b, and 3c and performs overall control, and a remote control unit 19 that controls the control unit 3 from the outside are provided.

  On the other hand, a hot water storage tank 4 for storing hot water, a water pipe 13 for supplying hot water to the hot water storage tank 4 from the outside, and a hot water supply pipe 14 for supplying hot water from the hot water storage tank to the hot water outlet 15 are provided. By operating the hot water supply port 15, hot water can be obtained as necessary. Here, the water pipe 13 is provided with a water tap 16 so that water does not flow backward from the hot water storage tank 4, and the hot water supply pipe 14 is provided with a hot water tap 17, respectively. The quantity supply is adjusted.

  In addition, the hot water storage tank 4 has a tank outbound pipe 10 for supplying hot water from the heat pumps 1a, 1b, and 1c, and water to the heat pump 4 (here, the water includes both cold water and hot water). A tank return pipe 11 for moving the pipe is connected. A bypass switching valve 12 is provided at the front ends of the tank forward piping 10 and the tank return piping 11. Furthermore, the heat pump side of the bypass switching valve 12 is provided with a heat pump forward piping 5 for supplying hot water from the heat pump side, and a heat pump return piping 6 for discharging water to the heat pump side. The heat pump forward pipe 5 and the heat pumps 1a, 1b, and 1c are connected by heat pump forward pipes 7a, 7b, and 7c, respectively, and the heat pump return pipe 6 and the heat pumps 1a, 1b, and 1c are respectively connected to the heat pump return pipe. They are connected by 8a, 8b, 8c. The heat pump return branch pipes 8a, 8b, and 8c are provided with check valves 9a, 9b, and 9c to prevent back flow of water.

  First, the operation of the heat pump hot water supply system of the present embodiment in a state where the external temperature is moderately high and there is no risk of freezing will be described. First, when the water level of the hot water storage tank 4 becomes below a certain level by using a large amount of hot water from the hot water supply port 15, the water tap 16 is adjusted to supply water from the water pipe 13, and the heat pumps 1a, 1b, 1c The circulation pumps 2a, 2b, and 2c are operated to heat the water supplied from the hot water storage tank 4. At this time, the bypass switching valve 12 is operated to connect the heat pump forward piping 5 and the tank forward piping 10 to the tank return piping 11 and the heat pump return piping 6 as shown in FIG. In this way, heat pumps 1a, 1b, 1c → heat pump forward branch pipes 7a, 7b, 7c → heat pump forward pipe 5 → bypass switching valve 12 → tank forward piping 10 → hot water storage tank 4 → tank return piping 11 → bypass switching valve 12 → Heat water heated by the heat pumps 1a, 1b, 1c is supplied to the hot water storage tank 4 by circulating water in the hot water supply circuit of the heat pump return pipe 6 → heat pump return branch pipes 8a, 8b, 8c → heat pump 1. Next, when the water level in the hot water storage tank 4 becomes a certain level or more, the amount of tap water supplied to the hot water storage tank 4 is reduced by adjusting the water tap 16, and the heat pumps 1b and 1c and the circulation pumps 2b and 2c are connected. The operation is stopped and only the heat pump 1a and the circulation pump 2a are operated. Further, when the water level inside the hot water storage tank 4 rises and becomes full, the supply of tap water to the hot water storage tank 4 is stopped and the operation of the heat pump 1a and the circulation pump 2a is also stopped.

  Thus, when the first hot water storage tank 4 is at a low water level, a large amount of hot water can be supplied in a short time by operating the three heat pumps 1a, 1b, and 1c simultaneously. Moreover, if the water level of the hot water storage tank 4 becomes a certain level or more, it is possible to save energy by reducing the number of heat pumps and circulation pumps. These controls are implemented by sending signals from the general control unit 18 to the control units 3a, 3b, 3c and the bypass switching valve 12. Further, by operating the remote control unit 19, it is possible to adjust the water level when operating with the number of heat pumps and circulation pumps reduced, and the temperature of the hot water supplied. At this time, since the external temperature is moderately high, the heat pump and the circulation pump that are stopped are not frozen. In addition, you may set the state which drive | operates two heat pumps and a circulation pump as needed.

  Next, the operation of the heat pump hot water supply system when the external temperature becomes low and a signal for predicting freezing is issued from the freezing sensor will be described. Here, one freezing sensor is installed inside each of the heat pumps 1a, 1b, and 1c, and when the temperature of the heat pump is sensed and falls below a certain level, it is predetermined that freezing is predicted. Is sent to the overall control unit 18 through the control units 3a, 3b, and 3c.

  The operation of the heat pump hot water supply system when the general control unit 18 receives the freeze prediction signal will be described below based on the flowchart of FIG. First, when a freeze prediction signal is received (S01), the number of operating heat pumps is confirmed. If it is determined that all of the heat pumps 1a, 1b, and 1c are operating (S02), this heat pump hot water supply system is operating abnormally. Therefore, at this time, a failure display is displayed at a predetermined place (S03), and the system is stopped (S04). It is also desirable to issue an alarm as necessary. On the other hand, when it is determined that some of the heat pumps 1a, 1b, and 1c are operating (S05), the hot water storage tank 4 is not full at a low water level. Therefore, in this case, it is confirmed that the hot water supply circuit is configured by the bypass switching valve 12 (S06), and the freeze prediction signal is generated in the heat pumps 1a, 1b, 1c and the circulation pumps 2a, 2b, 2c. The heat pump and the circulation pump that have been operated are operated (S07). When the freeze prediction signal is released in this way (S08), the operation of the heat pump and circulation pump that previously issued the freeze prediction signal is stopped (S10) (after this, a signal for predicting freezing is issued again). Then go back to the beginning and do the same.)

  If the freezing prediction signal is not canceled (S08), the hot water is supplied to the hot water storage tank 4 by operating the heat pump and the circulation pump until the hot water storage tank 4 is full (S09). Next, when the hot water storage tank 4 is full, the bypass switching valve 12 is switched as shown in FIG. 2B (S12). That is, the front ends of the tank outward piping 10 and the tank return piping 11 are closed, and the heat pumps 1a, 1b, 1c → the heat pump outward branching pipes 7a, 7b, 7c → the heat pump outward piping 5 → the bypass switching valve 12—the heat pump return piping. 6 → Heat pump return path branch pipes 8a, 8b, 8c → Heat pump heat pump 1 is configured as a bypass circuit. Then, among the heat pumps 1a, 1b, 1c, the circulation pump and the circulation pumps 2a, 2b, 2c, only the circulation pump of the heat pump that has issued the freeze prediction signal is operated (S13), and water is circulated by the bypass circuit. The circulating pump is operated until the freezing prediction signal is released. If the freezing prediction signal is released (S14), the operation of the circulating pump is stopped (S15).

When all the heat pumps are stopped (S11), the hot water storage tank 4 is full. Therefore, the hot water cannot be further supplied to the hot water storage tank 4. At this time, the bypass switching valve 12 was switched so as to constitute a bypass circuit (S12), and a freezing prediction signal was issued in the heat pumps 1a, 1b, 1c, the circulation pump, and the circulation pumps 2a, 2b, 2c. Only the circulation pump of the heat pump is operated (S13), and water is circulated in the bypass circuit. The circulating pump is operated until the freezing prediction signal is released. If the freezing prediction signal is released (S14), the operation of the circulating pump is stopped (S15). (Here, after determining that “a part of the heat pump is operating (S05)” and then determining that “all the heat pumps are not stopped (S11)”, the system operates abnormally. Therefore, the failure display (S16) is shown and the system is stopped (S17).
In the freeze prevention method of the heat pump hot water supply system of the present embodiment, the following effects can be obtained. First, if the hot water storage tank is not full, the heat pump and circulation pump that issued the freeze prediction signal are operated to supply hot water to the hot water storage tank, thereby preventing the heat pump from freezing and The temperature of the supplied hot water can be kept constant (at this time, if only the circulation pump is operated, the temperature of the supplied hot water will decrease). Further, if the freeze prediction signal is subsequently released, energy saving can be achieved by stopping the heat pump and the circulation pump that previously issued the freeze prediction signal.

  Further, when the hot water storage tank is full, the bypass switching valve is switched to the bypass circuit side, and only the circulation pump of the heat pump that has issued the freeze prediction signal is operated. Thus, by circulating water in the bypass circuit without supplying hot water to the hot water storage tank, freezing of the heat pump can be avoided and an energy saving effect can be obtained. (At this time, if the heat pump is also operated simultaneously, useless energy is used by supplying unnecessary hot water.) That is, the heat pump hot water supply system of the present embodiment predicts freezing of each heat pump. Since it has a freezing sensor, a control unit that controls each circulation pump, a general control unit that controls each control unit as a whole, and a bypass switching valve that switches between a hot water supply circuit and a bypass circuit, the general control By the unit, the amount of hot water supplied to each heat pump, circulation pump, and hot water storage tank can be intensively controlled. For this reason, freezing of the hot water supply system having a plurality of heat pumps can be effectively prevented without using a heater.

  Further, since the circulation pump of the heat pump whose freezing is predicted by the freezing sensor is operated, the freezing of the heat pump whose freezing is predicted can be surely prevented. Furthermore, when at least one of the heat pumps is in operation, it is characterized by operating the heat pump foreseeing freezing by a freezing sensor, so that a freezing prediction signal is issued when the hot water storage tank is not full. By operating the heat pump and the circulation pump to supply hot water to the hot water storage tank, it is possible to avoid freezing of the heat pump and to keep the temperature of the hot water supplied to the hot water storage tank constant.

  In addition, when all of the heat pumps have stopped operating, a bypass circuit is configured to operate the circulation pump of the heat pump in which freezing is predicted by the freeze sensor, so that the hot water storage tank is full. In the case of a tank, only the circulation pump of the heat pump that issued the freeze prediction signal is operated, and water is circulated in the bypass circuit without supplying hot water to the hot water storage tank, thereby preventing the heat pump from freezing. , Energy saving effect can be obtained.

It is a block diagram of the heat pump type hot water supply system of this embodiment. It is sectional drawing which shows the bypass switching valve of this embodiment. It is a flowchart which shows operation | movement of the heat pump type hot-water supply system of this embodiment. It is a basic block diagram of a conventional heat pump hot water supply system.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1a-1c Heat pump 2, 2a-2c Circulation pump 3, 3a-3c Control part 4 Hot water storage tank 5 Heat pump outgoing piping 6 Heat pump return piping 7a-7c Heat pump outgoing branch branch 8a-8c Heat pump backward branching tubes 9, 9a-9c Check valve 10 Tank outbound piping 11 Tank return piping 12 Bypass switching valve 13 Water pipe 14 Hot water pipe 15 Hot water outlet 16 Water tap 17 Hot water tap 18 General control section 19 Remote control section

Claims (4)

A plurality of heat pumps for heating water, a circulation pump for circulating water of each of the heat pumps, a freezing sensor for predicting freezing of each of the heat pumps, a control unit for controlling each of the circulation pumps, A general control unit for controlling the control unit as a whole, a hot water storage tank for storing hot water, a heat pump forward piping for discharging water from the heat pump, a heat pump return piping for supplying water to the heat pump, and supplying hot water to the hot water storage tank A tank outward piping and a tank return piping for discharging water from the hot water storage tank,
A water supply circuit in which water flows from the heat pump in the order of the heat pump forward piping, the tank forward piping, the hot water storage tank, the tank return piping, the heat pump return piping, and returns to each of the heat pump heat pumps. A heat pump hot water supply system comprising a bypass switching valve that switches between a heat pump forward piping and a bypass circuit in which water flows in the order of the heat pump backward piping and returns to the heat pump.   The heat pump hot water supply system according to claim 1, wherein when the freezing is predicted by the freezing sensor, a circulation pump of the heat pump is operated.   3. The heat pump hot water supply system according to claim 2, wherein when at least one of the heat pumps is in operation, the heat pump in which freezing is predicted by the freezing sensor is operated. 3. The heat pump system according to claim 2, wherein when all of the heat pumps are stopped, a bypass circuit is configured to operate a circulation pump of the heat pump in which freezing is predicted by the freezing sensor. Hot water system.

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