JP2009074736A - Heat pump type hot water supply device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently perform an antifreezing operation, with respect to a heat pump type hot water supply device comprising a hot water storage tank for storing the hot water produced by a heat pump unit and supplying hot water to a prescribed hot water supply spot. <P>SOLUTION: This heat pump type hot water supply device comprises a heat pump going pipe 9 connecting a lower portion of the hot water storage tank 2 and a refrigerant-water heat exchanger 5, a heat pump returning pipe 12 connecting the refrigerant-water heat exchanger and an upper portion of the hot water storage tank, a water supply pipe 11 connecting a lower portion of the hot water storage tank and a water line, and a circulation pump 10 disposed in the heat pump going pipe. A heat pump circulation circuit is formed by connecting the hot water storage tank, the heat pump going pipe, the refrigerant-water heat exchanger and the heat pump returning pipe, a three-way valve 13 is disposed in the heat pump returning pipe, an antifreezing bypass circuit is formed by connecting the three-way valve and the water supply pipe by a bypass pipe 14, and the heat pump circulation circuit, the antifreezing bypass circuit and a circuit for making the heat pump circulation circuit and the antifreezing bypass circuit simultaneously communicate, are switchable by the three-way valve. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a heat pump hot water supply apparatus that stores hot water generated by a heat pump unit and includes a hot water storage tank for supplying hot water to a predetermined hot water supply location, and in particular, a pipe that connects the heat pump unit and the hot water storage tank in an annular shape This is related to the prevention of freezing.

Conventionally, in this type of hot water supply device, a heat pump unit for supplying heat, hot water generated by the heat pump unit, and a hot water storage tank for supplying hot water to a predetermined hot water location, are generated by the heat pump unit. A circulation pump that circulates and supplies hot water to the hot water storage tank, a first hot water circulation path for returning hot water flowing out from the heat pump unit to the heat pump unit again through the hot water storage tank, and hot water flowing out from the heat pump unit , Bypassing the hot water storage tank and returning to the heat pump unit again, a three-way valve for switching between the first hot water circulation path and the second hot water circulation path, the outside air temperature or the circulating water temperature Temperature detecting means for detecting the second hot water circulation path while the boiling operation is stopped The path switching means is controlled to switch, and when the temperature detected by the temperature detection means is equal to or lower than a predetermined value, at least an operation control device that starts the operation of the circulation pump is provided. It was intended to prevent the hot water circulation path from freezing when the outside air temperature was low and the outside was stopped. (For example, see Patent Document 1)
JP 2003-139405 A

By the way, in this conventional system, when the freeze prevention operation in the second hot water circulation path continues for a certain period of time, when the three-way valve is switched to the first hot water circulation path side to perform the freeze prevention operation, cold water flows from the upper part of the hot water storage tank. Therefore, there is a problem that the high temperature part of the tank is mixed and the internal temperature is lowered. And there was a possibility that the temperature of the hot water fluctuated due to cold water stored in the upper part.
In addition, in order to suppress the inflow of cold water to the upper part of the hot water storage tank, when the flow rate of the circulation pump is reduced and the inflow speed is extremely reduced, the heat pump unit and the hot water storage tank unit are connected, and the piping part directly in contact with the outside air is frozen. There was a fear.
In addition, when the freeze prevention operation is alternately performed on the first and second hot water circulation paths, there is a problem that the drive time of the circulation pump is increased and the durability of the circulation pump is lowered.

  The present invention pays attention to this point and solves the above-mentioned drawbacks. In particular, the configuration includes a refrigeration circuit having a compressor, a refrigerant-to-water heat exchanger, a decompressor, and an evaporator in the heat pump unit, and the tank unit includes In a heat pump type hot water supply apparatus having a hot water storage tank for circulating the water heated by the refrigerant to water heat exchanger of the refrigeration circuit, the lower part of the hot water storage tank and the refrigerant to water heat exchanger are connected to each other A heat pump return pipe, a heat pump return pipe connecting the refrigerant to water heat exchanger and the upper part of the hot water storage tank, a water supply pipe connecting the lower part of the hot water storage tank and the water supply, and a circulation pump in the heat pump forward pipe, The hot water storage tank, the heat pump forward pipe, the refrigerant-to-water heat exchanger, and the heat pump return pipe are connected to form a heat pump circulation circuit, and a three-way valve is provided in the heat pump return pipe, and the three-way valve and the water supply pipe are connected to the bypass pipe. Are connected to each other to form a freeze prevention bypass circuit, and the three-way valve allows switching between the heat pump circulation circuit, the freeze prevention bypass circuit, and the circuit that simultaneously connects the heat pump circulation circuit and the freeze prevention bypass circuit. .

  According to the present invention, the heat pump circulation circuit of the heat pump type hot water supply apparatus and the antifreeze bypass circuit in each pipe in the heat pump hot water supply apparatus during the stoppage of the boiling operation at low outside air temperature are effectively prevented from freezing and the upper part of the hot water storage tank during the freezing operation. This minimizes the entry of cold water into the water and reduces the fluctuation of the hot water temperature.

Next, an embodiment of the present invention will be described with reference to the drawings.
Reference numeral 1 denotes a hot water storage tank unit for storing a hot water storage tank 2 or the like for storing hot water, and 3 denotes a heat pump unit as a heating means for heating the hot water in the hot water storage tank 2. The compressor 4 and the refrigerant-water as a condenser are contained therein. A heat exchanger 5, an electronic expansion valve 6 as a decompression device, and a forced air-cooled evaporator 7 are used. The refrigeration cycle of the heat pump unit 3 uses carbon dioxide as a refrigerant to constitute a supercritical heat pump cycle. It is what. Further, a heat pump control unit 8 for driving and controlling the heat pump cycle by the compressor 4 and the electronic expansion valve 6 is provided.

A heat pump forward pipe 9 connects the lower part of the hot water storage tank 2 and the refrigerant / water heat exchanger 5 to which a circulation pump 10 is attached.
Reference numeral 11 denotes a water supply pipe for connecting a water supply to the lower part of the hot water storage tank 1 to supply tap water.
A heat pump return pipe 12 connects the refrigerant-water heat exchanger 5 and the upper part of the hot water storage tank 2. The heat pump return pipe 12 in the tank unit 1 is provided with a three-way valve 13, and the three-way valve 13 and the water supply A pipe 11 is connected and a bypass pipe 14 is provided.

  The three-way valve 13 is connected to the upstream connection port 13 a connected to the return pipe 12 a on the heat pump unit 3 side, the downstream connection port 13 b connected to the return pipe 12 b on the hot water storage tank 2 upper side, and the bypass pipe 14. In the boiling operation performed at midnight, the upstream side connection port 13a and the downstream side connection port 13b are communicated with each other to connect the hot water storage tank 1 → the circulation pump 10 → the heat pump forward pipe 9 → refrigerant-water. The heating operation is performed by the heat exchanger circuit 15 of the heat exchanger 5 → the return pipe 12 a → the three-way valve 13 → the return pipe 12 b → the hot water storage tank 2.

  Reference numeral 16 denotes an antifreezing bypass circuit, which connects the upstream side connection port 13a and the bypass side connection port 13c of the three-way valve 13, and connects the hot water storage tank 1 → the circulation pump 10 → the heat pump forward pipe 9 → the refrigerant-water heat exchanger 5 → return. By circulating water in the lower part of the hot water storage tank 2 in the order of the pipe 12a → the three-way valve 13 → the bypass pipe 14 → the water supply pipe 11 → the hot water storage tank 2, the heat pump forward pipe 9 between the tank unit 1 and the heat pump unit 3 is returned. In the pipe 12, the portion where the temperature is most lowered and the possibility of freezing is large is prevented from freezing.

  The three-way valve 13 has a function of simultaneously communicating the three directions of the upstream connection port 13a, the downstream connection port 13b, and the bypass connection port 13c. When the outside air temperature is low, the piping freezes first from the lowest temperature of the hot water circulation path, so the temperature of the portion directly in contact with the outside air of the heatpone return pipe 9 and the heatpone return pipe 12 is lowered, so that normal In the freeze prevention operation, the bypass circuit 16 is prevented from freezing by circulating the water below the hot water storage tank 1 to the freeze prevention bypass circuit 16.

  Since the temperature inside the tank unit 1 is about 5 ° C. higher than that of the outside air, the possibility of freezing is lower than that of the pipe that directly contacts the outside air. Therefore, by connecting the three-way connection ports of the three-way valve 13 at the same time, the pipe portion in the low temperature has a large flow rate, and the pipe in the tank unit 1 having a relatively high temperature is made to flow efficiently at about half the flow rate. In particular, the piping can be prevented from freezing.

  Reference numeral 17 denotes a discharge pipe connected to the upper part of the hot water storage tank 2 for discharging hot water stored in the hot water. A water supply bypass pipe 18 guides tap water from the water supply pipe 11 to the hot water outlet side. A hot water supply mixing valve 19 mixes hot water from the hot water discharge pipe 17 and tap water from the water supply bypass pipe 18 to a hot water supply set temperature. A hot water supply pipe 20 supplies hot water from the hot water supply mixing valve 19 to the hot water tap 21. Reference numeral 22 denotes a hot water supply temperature sensor provided in the hot water supply pipe 20. A hot water supply flow sensor 23 is provided in the hot water supply pipe 20. A water supply temperature sensor 24 is provided in the water supply pipe 11. A pressure reducing valve 25 is provided in the water supply pipe 11. A check valve 26 is provided in the water supply pipe 11 and prevents the water in the tank 2 from flowing back to the water supply side. Reference numeral 27 denotes an overpressure relief valve connected to the outlet pipe 17. A remote control 28 is installed in a kitchen or the like, and is connected to the hot water storage tank unit 1 by a remote controller for stopping the operation of the hot water supply device, setting the hot water supply temperature, and setting various operation modes. A hot water supply control device 29 is connected to the heat pump control unit 8 and the remote control 28 and controls the entire hot water supply device.

  Reference numeral 30 denotes a hot water storage temperature sensor provided with a number of thermistor sensors in the vertical direction of the side surface of the hot water storage tank 2, and detects the temperature and amount of hot water in the hot water storage tank 2.

  31 is a blower which blows with a propeller fan in order to perform heat exchange of the evaporator 7. An outside air temperature sensor 32 is provided on the windward side of the evaporator 7 and measures the outside air temperature. Reference numeral 33 denotes a heat exchange inlet temperature sensor provided at a connection portion between the refrigerant-water heat exchanger 5 and the heat-pump forward pipe 9, and detects a cold water temperature before heating. Reference numeral 34 denotes a heat exchange outlet temperature sensor provided at the connecting portion of the refrigerant-water heat exchanger 5 and the heat-pump return pipe 12 for detecting the hot water temperature after heating.

  The remote control 28 has a push-type power switch 35, a temperature setting switch 36 for setting a hot water supply set temperature, a hot water switch 37 for instructing a hot water filling to a bathtub (not shown), and a hot water amount for setting the hot water amount. An operation unit 40 having a setting switch 38 and a remaining time display switch 39 for displaying the remaining time for hot water supply, a display unit 41 formed of a dot matrix type fluorescent display tube, and the operation unit 40 and the display unit 41. A remote control unit (not shown) mainly configured with a microcomputer that controls and communicates with the hot water supply control unit 29 is provided, and is set in the display unit 41 by the operation unit 40 during normal operation. The hot water supply set temperature, time information, and the remaining hot water storage amount detected by the hot water storage temperature sensor 22 are displayed. The display unit 41 may be a dot matrix type liquid crystal display unit.

  Here, the power supply of the hot water supply device is an electric light according to time zone, and it is set at a cheap electricity rate at night (here from 23:00 to 7:00 the next day). It heats up the amount of hot water required for the day and uses it for this purpose. Also, with this hourly lamp, power is supplied even during the daytime (from 7:00 to 23:00), and is added when the amount of remaining hot water decreases. Is heated.

  When the night time zone is reached, the hot water supply control unit 29 calculates the amount of hot water storage required for the next day, and instructs the heat pump control unit 8 to boil up the target hot water storage amount by the end of the night time zone. The circuit is activated and the circulation pump 10 of the heat pump circulation circuit 15 is started to be driven. Then, hot water taken out from the lower part of the hot water storage tank 2 by driving the circulation pump 10 flows into the refrigerant-water heat exchanger 5 through the heat pump forward pipe 9 and is heated, and is heated to the upper part of the hot water tank 2 through the heat pump return pipe 12. The hot water is stored by being returned to.

  Further, when the hot water storage temperature sensor 30 provided on the side surface of the hot water storage tank 2 detects that a predetermined amount of hot water has been stored, or when the heat exchange inlet temperature sensor 33 detects a predetermined temperature or more, a hot water supply control unit 29 instructs the heat pump control unit 8 to stop the heating operation, the operations of the heat pump circulation circuit 15 and the circulation pump 10 are stopped, and the hot water storage operation is completed by the end of the night time zone.

  Here, the amount of heat stored in the hot water storage tank 2 is calculated by the hot water supply control unit 29 as a target amount of heat stored in the hot water supply load for the past several days. Varies in the range of 60 ° C. to 90 ° C. depending on the season (or the feed water temperature detected by the feed water temperature sensor 24) and the amount of target hot water stored.

  Next, when the hot water tap 21 is opened, the hot water in the upper part of the hot water storage tank 2 is pushed out to the hot water discharge pipe 17 by the water supply pressure from the water supply pipe 11, and the hot water mixing valve 19 controlled by the hot water supply control unit 29 The low temperature water 18 and the temperature detected by the hot water supply temperature sensor 22 are mixed so as to become the hot water supply set temperature set by the operation unit 40 of the remote controller 28, and hot water is supplied via the hot water supply pipe 20.

  If the amount of hot water supply becomes larger than usual, the hot water supply control unit 29 detects that the remaining hot water storage amount detected by the hot water storage temperature sensor 30 has decreased during the daytime power hours, and the hot water is stored in the hot water storage tank 2. When hot water is expected to run out, the necessary amount of heat is increased using the daytime power at that time.

  Next, with reference to FIG. 2, a first embodiment of the anti-freezing operation while the boiling operation is stopped will be described. The freeze prevention operation is performed only when the boiling operation is stopped in S1. During the boiling operation, hot water circulates in the heat pump circulation circuit 15 to store hot water, and hot water also increases in the hot water storage tank 2, so there is no need to worry that the heat pump circulation circuit 15 freezes. In S2, the temperature sensors 32, the heat exchange inlet temperature sensor 33, the water supply temperature sensor 24, and the like are read.

  Next, in S3, it is compared whether the current value T of the outside air temperature sensor 32 is lower than a predetermined temperature T1 (for example, 3 ° C.). In the case of Yes, it progresses to S4, and in No, it returns to S2. In S4, when the three-way valve 13 is switched to the bypass pipe 14 side so that the upstream side connection port 13a and the bypass side connection port 13c communicate with each other and the circulation pump 10 is operated, the water in the lower part of the hot water storage tank 2 is transferred to the freeze prevention bypass circuit 16. Start circulation. Then, the timer t is started. In S5, it is compared whether or not the first predetermined time t1 (2 hours in this embodiment) has elapsed. If Yes, the process proceeds to S6, and if No, remains in S5.

  In S6, the operation of the three-way valve 13 in which the upstream side connection port 13a, the downstream side connection port 13b, and the bypass side connection port 13c communicate in three directions and water flows simultaneously to the bypass pipe 14 side and the return pipe 12b side is a second predetermined operation. By performing the time t2 (30 seconds in this embodiment), about half of the water flows through the return pipe 12b to prevent freezing. Since there is a temperature difference of about 5 ° C. between the temperature in the hot water storage tank unit 1 and the outside air temperature, the return pipe 12b and the bypass pipe 14 have better freezing conditions than the piping part directly exposed to the outside air, so that even at half the flow rate, freezing prevention is achieved. It is something that can be done. Further, since the amount of cold water entering the upper part of the hot water storage tank 2 by this operation is very small, the influence on the hot water in the hot water storage tank 2 is extremely small.

  Next, in S7, it is compared whether or not the value T of the outside air temperature sensor 32 is higher than the predetermined temperature T1 (3 ° C.). If Yes, the process proceeds to S8, and if No, the process returns to S2. In S8, the circulation pump 10 is stopped from the determination that the freeze prevention operation is not necessary, the timer t is also stopped, and the process returns to S2.

In this way, efficient freezing prevention of each pipe of the heat pump circulation circuit 15 and the freezing prevention bypass circuit 16 and the entry of cold water into the upper part of the hot water storage tank 2 during the freezing prevention operation can be minimized, and the hot water temperature It is possible to reduce the fluctuation of
In this embodiment, the freeze prevention control is performed based on the value of the outside air temperature sensor 32, but the same effect can be obtained by using the values of the heat inlet temperature sensor 33 and the feed water temperature sensor 24 instead of the outside air temperature sensor 32. Is obtained.

  Next, a second embodiment will be described with reference to FIG. The freeze prevention operation is performed only when the boiling operation is stopped in S9. Next, in S10, reading of each temperature sensor such as the outside air temperature sensor 32, the heat exchange inlet temperature sensor 33, and the water supply temperature sensor 24 is performed.

  Next, in S11, it is compared whether the current value T of the outside air temperature sensor 32 is lower than a predetermined temperature T1 (for example, 3 ° C.). In the case of Yes, it progresses to S12, and in No, it returns to S10. In S12, when the three-way valve 13 is switched to the bypass pipe 14 side so that the upstream side connection port 13a and the bypass side connection port 13c communicate with each other and the circulating pump 10 is operated, the water in the lower part of the hot water storage tank 2 is transferred to the freeze prevention bypass circuit 16. Start circulation. In S13, whether or not the outside air temperature sensor 32 is lower than a second predetermined temperature T2 (for example, −3 ° C.) lower than the first predetermined temperature T1 (3 ° C.) is compared. If Yes, the process proceeds to S14. Returns to S10.

  Next, in S14, the three-way valve 13 is connected to the upstream connection port 13a, the downstream connection port 13b, and the bypass connection port 13c in three directions so that water flows simultaneously to the bypass tube 14 side and the return tube 12b side. As a result, about half of the water flows through the return pipe 12b to prevent freezing. Since there is a temperature difference of about 5 ° C. between the temperature in the hot water storage tank unit 1 and the outside air temperature, the return pipe 12b and the bypass pipe 14 have better freezing conditions than the piping part directly exposed to the outside air, so that even at half the flow rate, freezing prevention is achieved. It is something that can be done. Further, since the amount of cold water entering the upper part of the hot water storage tank 2 by this operation is very small, the influence on the hot water in the hot water storage tank 2 is extremely small.

Next, in S15, the present outside air temperature T is compared with the first predetermined temperature T1 and the second predetermined temperature T2, and when the temperature is between both temperatures, the process returns to S12, and otherwise, the process returns to S14. In this way, efficient freezing prevention of each pipe of the heat pump circulation circuit 15 and the freezing prevention bypass circuit 16 and the entry of cold water into the upper part of the hot water storage tank 2 during the freezing prevention operation can be minimized, and the hot water temperature It is possible to reduce the fluctuation of
In this embodiment, the freeze prevention control is performed based on the value of the outside air temperature sensor 32, but the same effect can be obtained by using the values of the heat inlet temperature sensor 33 and the feed water temperature sensor 24 instead of the outside air temperature sensor 32. Is obtained.

The schematic block diagram of the hot water storage type hot water supply apparatus of one Embodiment of this invention. The flowchart of the said 1st Example. The flowchart of the said 2nd Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hot water storage tank unit 2 Hot water storage tank 3 Heat pump unit 5 Refrigerant-water heat exchanger 8 Heaton control part 9 Heaton outgoing pipe 10 Circulation pump 12 Heaton return pipe 13 Three-way valve 14 Bypass pipe 15 Heaton circulation circuit 16 Freezing prevention bypass circuit 29 Hot water supply control Part 32 Outside air temperature sensor

Claims (3)

  A refrigeration circuit having a compressor, a refrigerant-to-water heat exchanger, a decompressor, and an evaporator is provided in the heat pump unit, and water heated by the refrigerant-to-water heat exchanger of the refrigeration circuit is circulated in a tank unit so as to be stored. In a heat pump type hot water supply apparatus comprising a hot water storage tank, a heat pump forward pipe connecting a lower portion of the hot water storage tank and a refrigerant to water heat exchanger, and an upper portion of the refrigerant to water heat exchanger and the hot water storage tank are provided. A heat pump return pipe to be connected, a water supply pipe connecting the lower part of the hot water storage tank to the water supply, and a circulation pump in the heat pump forward pipe, wherein the hot water storage tank, the heat pump forward pipe, the refrigerant-to-water heat exchanger, and the heat pump return pipe communicate with each other. A heat-pump circulation circuit is formed, a three-way valve is provided in the heat-pump return pipe, and a freezing prevention bypass circuit is formed by connecting the three-way valve and a water supply pipe with a bypass pipe. And Coupon circulation circuit, the antifreezing bypass circuit, a heat pump type hot water supply apparatus is characterized in that a switchable circuit that communicates simultaneously antifreeze bypass circuit and Hipon circulation circuit.   While the boiling operation is stopped, the value of the outside air temperature sensor provided in the ventilation path to the evaporator of the heat pump unit, the circulating water temperature sensor provided in the heat pump circulation circuit, or the value of the feed water temperature sensor provided in the water supply pipe When the temperature is lower than the first predetermined temperature, only the antifreezing bypass circuit is operated, and when the antifreezing operation of the antifreezing bypass circuit has elapsed for a predetermined time, the heat pump circulation circuit and the antifreezing bypass circuit are simultaneously connected. The heat pump type hot water supply apparatus according to claim 1, further comprising an operation control apparatus that operates by switching a circuit.   While the boiling operation is stopped, the value of the outside air temperature sensor provided in the ventilation path to the evaporator of the heat pump unit, the circulating water temperature sensor provided in the heat pump circulation circuit, or the value of the feed water temperature sensor provided in the water supply pipe Between the first predetermined temperature and a second predetermined temperature lower than the first predetermined temperature, the freeze prevention bypass circuit is operated, or when the sensor value is lower than the second predetermined temperature, the heat pump 2. The heat pump type hot water supply device according to claim 1, further comprising an operation control device that operates the circulation circuit and the freeze prevention bypass circuit in communication at the same time.

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