JPH0157269B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a water heater that supplies hot water using a heat pump.

In typical prior art, the water heated by the condenser of the heat pump is further heated by another heat exchanger through which the coolant of the internal combustion engine that drives the compressor of the heat pump passes. Water from the second heat exchanger is led to a hot water storage tank, and a closed circulation loop is formed by the hot water storage tank, the first heat exchanger, and the second heat exchanger.

In such prior art, in order to control the temperature of the hot water storage tank, it is necessary to control the flow rate of the circulation pump interposed in the closed circulation loop, making the configuration complicated. Furthermore, if the flow rate of the circulation pump is reduced, the heat transfer area of the first heat exchanger must be increased, which increases the size of the structure. Furthermore, when the flow rate of the circulation pump is reduced, a temperature difference occurs between the circulating water temperature and the condensed refrigerant, and the refrigerant pressure of the heat pump increases. Therefore, the load on the internal combustion engine that drives the compressor of the heat pump increases, and there is a risk that the internal combustion engine will stop. Alternatively, the heat of condensation of the refrigerant cannot be sufficiently transferred to the hot water. On the other hand, if the flow rate is not controlled, the predetermined temperature cannot be achieved until the water in the hot water storage tank rises entirely, which takes time.

The purpose of the present invention is to eliminate the need to control the flow rate of the circulation pump, have a simple configuration, allow for miniaturization, have a quick start-up time for hot water supply, and prevent the driving force of the heat pump from increasing unnecessarily. An object of the present invention is to provide an improved water heater.

FIG. 1 is a system diagram of an embodiment of the present invention. The water heater 1 is a first water heater that condenses the refrigerant of the heat pump 2.
a second heat exchanger 4 that further raises the temperature of the water heated by the first heat exchanger 3;
A hot water storage tank 5 that stores water heated by the second heat exchanger 4 and a circulation pump 6 are connected in this order to the first circulation closed loop, and the water is circulated by the circulation pump 6. heated. This first circulation closed loop includes a downstream side of the second heat exchanger 4,
A bypass conduit 7 is formed by short-circuiting the upstream side of the circulation pump 6. This bypass pipe line 7 connects the inlet and outlet of the hot water storage tank 5. This bypass line 7 is provided with an auxiliary tank 8 and a solenoid valve 9 in this order toward the circulation pump 6.
The hot water storage tank 5 has upper outlet pipes 43 at the upper and lower parts.
and a lower outlet conduit 41 are provided. Hot water storage tank 5
In the middle of the lower outlet pipe 41 provided at the lower part of the
A solenoid valve 42 is provided. An upper outlet pipe line 43 is formed by connecting the downstream side of the electromagnetic valve 42 and the upstream side of the short-circuit point 10 to the upper part of the hot water storage tank 5 . A solenoid valve 44 is provided in the middle of the upper outlet pipe 43. Water such as tap water is supplied to the lower part of the hot water storage tank 5 from a pipe 13 via a valve 12.
A temperature detector 14 is provided at the top of the hot water storage tank 5 . Further, a temperature detector 15 is provided on the exit side of the first heat exchanger 3, and a temperature sensor 16 is also provided on the exit side of the second heat exchanger 4. The temperature detectors 14, 15, 16 are realized by, for example, thermistors.

The compressor 18 of the heat pump 2 is driven by an internal combustion engine 19. The refrigerant from the compressor 18 is led to the heat exchanger 3 via a pipe 20 and condensed.
At this time, the water pumped by the pump 6 absorbs condensation heat in the heat exchanger 3, is heated, and is led to the second heat exchanger 4. The refrigerant condensed by the heat exchanger 3 is led to the expansion valve 21 via the pipe 50, reduced in pressure, and led to the evaporator 22. The evaporated refrigerant passes through the pipe 23 and returns to the compressor 18.
be guided by In this way, the refrigerant forms a closed circulation loop.

The hot cooling water from the jacket 26 of the internal combustion engine 19 is led via the line 24 to the second heat exchanger 4. The coolant whose temperature has been lowered by heat exchange in the heat exchanger 4 is further led to the radiator 25 where the temperature is further lowered, and then the cooling water is sent to the jacket 26 of the internal combustion engine 19.
is guided to cool the internal combustion engine 19.

FIG. 2 is a block diagram showing the electrical configuration of the embodiment shown in FIG. Temperature detector 14, 15, 16
is connected to the processing circuit 17. This processing circuit 17 controls the opening and closing operations of the solenoid valves 9, 42, and 44 in response to the outputs from the temperature detectors 14, 15, and 16, thereby making it possible to control the outlet hot water temperature to a desired temperature. Become.

The specific operation will be explained in detail below.

The low-temperature water supplied from the pipe line 13 is pressure-fed by the circulation pump 6 from the lower part of the hot water storage tank 5 through the lower outlet pipe line 41, and is guided to the first heat exchanger 3. The water heated by the first heat exchanger 3 is further heated by the second heat exchanger 4. The temperature of the heated water flowing out from the second heat exchanger 4 is detected by the temperature detector 16, and the detected temperature is set to a predetermined first temperature t1 (for example, 65°C).
When it is less than 1, the processing circuit 17 controls the solenoid valves 42 and 44 to close, and the solenoid valve 9 to open. Thereby, a second circulating closed loop is formed by the bypass line 7, the first heat exchanger 3, and the second heat exchanger 4. Since the second circulation closed loop is formed in this way, there is no need to control the flow rate of the circulation pump as in the conventional case, and the configuration can therefore be simplified. Further, by forming the bypass pipe 7, it becomes possible to efficiently raise the temperature in a short time.

The temperature of the water circulating in the second closed circulation loop is detected by the temperature detector 16 to be higher than the predetermined first temperature t1, and the temperature detector 14 in the hot water storage tank 5 The upper temperature of the hot water in the hot water storage tank 5 thus detected is a predetermined second temperature t2 (for example, 60°C) lower than the temperature t1.
When the temperature is less than 1, the solenoid valve 44 is opened, the solenoid valves 9 and 42 are closed, and the first heat exchanger 3, the second heat exchanger 4, and the upper outlet pipe 43 A third circular closed loop is thus formed. When the temperature detected by the temperature detector 16 is less than t1 while circulating in this closed loop, the solenoid valve 9 is in an open state and the solenoid valve 4 is in an open state.
2 and 44 are in a closed state, and the bypass pipe line 7,
The low-temperature water is heated by circulating in the second circulation closed loop formed by the first heat exchanger 3 and the second heat exchanger 4. In this manner, when the temperature detected by the temperature detector 16 is equal to or higher than t1, hot water is stored in the hot water storage tank 5, as described above.

When the temperature detected by the temperature detector 16 is equal to or higher than a predetermined temperature t1, and the temperature detected by the temperature detector 14 is equal to or higher than t2, the solenoid valve 42 is opened, and the solenoid valves 9 and 44 are closed. In the valve state, the lower outlet pipe 41, the first heat exchanger 3, and the second heat exchanger 4 form the aforementioned first circulation closed loop. When the temperature of the water circulated in this first closed loop is detected by the temperature sensor 16 to be less than t1, the solenoid valve 42,
44 is in the closed state, and the solenoid valve 9 is in the open state, and a second closed circulation loop is formed by the bypass pipe 7, the first heat exchanger 3, and the second heat exchanger 4 in the same manner as described above. The circulating water is heated.

In addition, while circulating in the second circulation closed loop, the temperature detector 15 detects that the outlet temperature from the first heat exchanger 3 is equal to or higher than a predetermined temperature t3 (for example, 50° C.). When it is done,
With the solenoid valves 9 and 44 closed and the solenoid valve 42 opened, low-temperature water is guided from the pipe 13 to the first heat exchanger 3 via the pipe 41. In this way, it becomes possible to efficiently absorb heat from the heat exchangers 3 and 4.

In this way, the opening and closing operations of the solenoid valves 9, 42, and 44 are controlled to selectively form three closed circulation loops, so there is no need to heat the entire hot water storage tank 5, and the water is heated to the desired set temperature. It becomes possible to raise the temperature in a short time.

Although the auxiliary tank 8 was provided in the middle of the bypass line in the above embodiment, it is not necessary to provide the auxiliary tank 8 when the capacity of the bypass line is large. Further, although the temperature detector 14 is provided on the outlet side of the first heat exchanger 3, it may be provided on the conduit 50 side of the heat pump 2.

Further, as shown in the third figure, the bypass pipe line 7 may be omitted. Note that in this case, the upper outlet pipe 43 can serve as the bypass pipe 7, so that it can efficiently absorb heat from the first heat exchanger 3 and the second heat exchanger 4 to provide the desired amount of heat. It becomes possible to raise the temperature to

Although exhaust heat from an internal combustion engine is used as the heat source for the second heat exchanger 4, a heater or the like may be used to heat the water from the first heat exchanger 3.

As described above, according to the present invention, it is possible to efficiently absorb heat from the first heat exchanger and raise the temperature to a desired temperature in a short time. Furthermore, since the bypass pipe is provided, there is no need to control the flow rate of the circulation pump, which makes it possible to downsize the entire water heater, and furthermore prevents the driving force of the heat pump from increasing unnecessarily.

[Brief explanation of drawings]

FIG. 1 is a system diagram of one embodiment of the present invention, FIG. 2 is a block diagram showing the electrical configuration of the embodiment shown in FIG. 1, and FIG. 3 is a system diagram of another embodiment of the invention. 1... Water heater, 2... Heat pump, 3, 4
... Heat exchanger, 5 ... Hot water storage tank, 6 ... Circulation pump, 7 ... Bypass pipe, 9, 42, 44 ...
Solenoid valve, 14, 15, 16...Temperature detector, 17
... processing circuit, 18 ... compressor, 19 ... internal combustion engine, 41 ... lower outlet pipe, 43 ... upper outlet pipe.

Claims (1)

[Claims] 1. A first heat exchanger that condenses the refrigerant of the heat pump, a second heat exchanger that further increases the temperature of water heated by the first heat exchanger, and a second heat exchanger that condenses the refrigerant of the heat pump. A hot water storage tank that stores water heated by a heat exchanger and a circulation pump are connected in this order to a circulation loop, and the water in the hot water storage tank is circulated by the circulation pump, and the water in the hot water storage tank is distributed to the upper and lower parts of the hot water storage tank. valve means are provided in association with the upper outlet line and the lower outlet line, such that the outlet temperature of the second heat exchanger is led to the first heat exchanger via the provided outlet line; When the temperature is equal to or higher than the predetermined first temperature and the upper temperature of the hot water storage tank is lower than the predetermined second temperature, which is lower than the first temperature, the first heat exchanger and the second heat exchanger and a closed circulation loop is formed by the upper outlet pipe, and when the outlet temperature of the second heat exchanger is equal to or higher than the first temperature and the upper temperature of the hot water storage tank is equal to or higher than the second temperature, , a first heat exchanger, a second heat exchanger, and a lower outlet pipe line to form a closed circulation loop. 2. A bypass pipe is provided by short-circuiting the inlet and outlet of the hot water storage tank, and a valve means is provided in association with the bypass pipe, and the outlet temperature of the second heat exchanger is lower than the first temperature. 2. The water heater according to claim 1, wherein the first heat exchanger, the second heat exchanger, and the bypass pipe line form a closed circulation loop. 3. The condenser of the heat pump is driven by an internal combustion engine, and the coolant of the internal combustion engine is circulated and supplied to the second heat exchanger. Water heater as described in section. 4. The water heater according to claim 1 or 2, wherein the second heat exchanger includes a heater or a gas burner powered by electricity.