JP2014129989A - Hot water storage type water heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hot water storage type water heater which does not perform a wasteful freeze prevention operation.SOLUTION: The hot water storage type water heater comprises: an outside temperature sensor 52; a hot water storage tank 2; a plurality of hot water storage temperature sensors 39 arranged in the lower vertical direction from the upper part of the hot water storage tank 2; heating means 3; a middle hot water discharge pipe 24 connected to a position lower than a hot water discharge pipe of the hot water storage tank 2; a middle hot water mixing valve 25 for mixing high-temperature water from the hot water discharge pipe and middle hot water from the middle hot water discharge pipe; and a middle hot water temperature sensor 55 arranged between the hot water storage tank 2 of the middle hot water discharge pipe 24 and the middle hot water mixing valve 25. Since the freeze prevention operation is performed when a detection temperature of the outside temperature sensor 52 is not higher than the prescribed temperature and a detection temperature of the hot water storage temperature sensor 39 is not higher than the prescribed temperature, and also when a detection temperature of the middle hot water temperature sensor 55 has become not higher than the prescribed temperature, the freeze of parts at the surroundings of the hot water storage tank 2 and the middle hot water discharge pipe 24 can be prevented.

Description

  The present invention relates to a hot water storage type hot water supply apparatus that boils hot water with a heating means and stores the hot water in a hot water storage tank.

  Conventionally, in this type, the water supplied from the lower part of the hot water storage tank is heated by the water / refrigerant heat exchanger of the heat pump unit, which is a heating means, and heated by the outlet temperature sensor provided at the outlet of the water / refrigerant heat exchanger. When the hot water temperature is detected and this temperature is lower than the hot water storage temperature at the upper part of the hot water storage tank by the hot water storage temperature sensor at the upper part of the hot water storage tank, the heated hot water is returned to the lower part of the hot water tank with the three-way valve as the bypass pipe side. For the first time, the three-way valve was switched to the return pipe side, and the boiling operation to supply heated hot water to the upper part of the hot water storage tank was started. (For example, Patent Document 1)

  In addition, by using a mixing valve that mixes the three fluids of medium temperature water, feed water, and high temperature water generated in the hot water storage tank, COP can be reduced by actively using medium temperature water for hot water filling and hot water filling to the bathtub. It was intended to improve. (For example, Patent Document 2)

  In this conventional apparatus, when the temperature of the outside air decreases and the temperature of the water entering the heat pump unit as the heating means and the temperature of the can body of the hot water storage tank are below the predetermined temperature, a boiling operation is performed, and the hot water is stored in the hot water storage tank. By storing the water, the piping and parts around the hot water storage tank were prevented from freezing.

  In order to prevent freezing of pipes connected to the heat pump unit, which is a heating means, when the outside air temperature falls to a predetermined temperature, the circulation pump in the heat pump unit is driven, and the low temperature water in the lower part of the hot water tank is transferred to the lower part of the hot water tank. The pipe connected to the heat pump unit is prevented from freezing by circulating between the heat pump unit and the heat pump unit.

JP 2009-264617 A JP 2009-127999 A

  By the way, in this conventional system, when the outside air temperature falls to a predetermined temperature, the circulating pump in the heat pump unit is driven so that the pipe connected to the heat pump unit does not freeze, and the low temperature water in the lower part of the hot water tank is Circulates between the heat pump unit and the heat pump unit, but the circulating low-temperature water is cooled by the outside air, and the incoming water temperature entering the heat pump unit gradually decreases.

  However, when the pipe connected to the heat pump unit is short or the insulation material is wound around the pipe or joint, the incoming water temperature to enter the heat pump unit will reach the specified temperature even if the outside air temperature decreases. As a result, the piping and parts around the hot water storage tank are not prevented from freezing due to the boiling operation, and the piping and parts around the hot water storage tank may freeze.

In order to solve the above-mentioned problem, in claim 1 of the present invention, an outside air temperature sensor for detecting outside air temperature, a water supply pipe connected to the lower end portion, and a hot water outlet pipe for discharging hot water stored in the hot water are provided. A hot water storage tank connected to the upper end, a plurality of hot water temperature sensors arranged in the vertical direction from the top to the bottom of the hot water storage tank, heating means for heating the hot water in the hot water storage tank to a high temperature, and the hot water storage tank The hot water outlet pipe connected to a lower position than the hot water outlet pipe for discharging the intermediate hot water from the hot water storage tank, the hot water from the hot water outlet pipe, and the intermediate temperature water from the intermediate hot water hot water outlet pipe are mixed to set the temperature. In the hot water storage type hot water supply apparatus comprising a medium temperature water mixing valve as a mixed water and a medium temperature water temperature sensor provided between a hot water storage tank of the medium temperature water discharge pipe and a medium temperature water mixing valve, the outside air temperature If the temperature detected by the sensor is below the specified temperature One When the hot-water storage temperature sensed temperature of the sensor is below a predetermined temperature, are those rows antifreezing operation when the temperature it detects the medium-temperature water temperature sensor further falls below the predetermined temperature.

  According to a second aspect of the present invention, there is provided a hot water storage tank in which an outside air temperature sensor for detecting the outside air temperature and a water supply pipe are connected to the lower end portion, and a hot water discharge pipe for discharging the hot water stored in the hot water is connected to the upper end portion. A plurality of hot water storage temperature sensors arranged in the vertical direction from the top to the bottom of the hot water storage tank, heating means for heating hot water in the hot water storage tank to a high temperature, and a position lower than the outlet pipe of the hot water storage tank A medium-temperature water mixing valve that is connected and mixes a medium-temperature water discharge pipe that discharges medium-temperature water from the hot water storage tank, and high-temperature water from the discharge pipe and medium-temperature water from the medium-temperature water discharge pipe to form a mixed water of a set temperature. A hot water temperature sensor provided between the hot water storage tank of the hot water outlet pipe and the hot water mixing valve, a hot water flow rate counter for counting the amount of hot water to be supplied, and a timing means for counting time. In the hot water storage hot water supply system When the temperature detected by the outside air temperature sensor is lower than a predetermined temperature and the temperature detected by the hot water storage temperature sensor is lower than the predetermined temperature, and when the stop time of the hot water flow rate counter is longer than the predetermined time, the freeze prevention operation is performed. It is.

  According to a third aspect of the present invention, there is provided a hot water storage tank in which an outside air temperature sensor for detecting the outside air temperature and a water supply pipe are connected to the lower end portion, and a hot water discharge pipe for discharging the hot water stored in the hot water is connected to the upper end portion. A plurality of hot water storage temperature sensors arranged in the vertical direction from the top to the bottom of the hot water storage tank, heating means for heating hot water in the hot water storage tank to a high temperature, and a position lower than the outlet pipe of the hot water storage tank A medium-temperature water mixing valve that is connected and mixes a medium-temperature water discharge pipe that discharges medium-temperature water from the hot water storage tank, and high-temperature water from the discharge pipe and medium-temperature water from the medium-temperature water discharge pipe to form a mixed water of a set temperature. A medium temperature water temperature sensor provided between the hot water storage tank of the medium temperature water discharge pipe and the medium temperature water mixing valve, a bath flow rate counter for counting the amount of hot water filling the bathtub, and a time measuring means for counting time In the hot water storage hot water supply equipment When the temperature detected by the outside air temperature sensor is lower than a predetermined temperature and the temperature detected by the hot water storage temperature sensor is lower than the predetermined temperature, and the bath flow counter is stopped for a predetermined time or longer, the freeze prevention operation is performed. It is.

  According to a fourth aspect of the present invention, there is provided a hot water storage tank in which an outside air temperature sensor for detecting the outside air temperature and a water supply pipe are connected to the lower end portion, and a hot water discharge pipe for discharging the hot water stored in the hot water is connected to the upper end portion. A plurality of hot water storage temperature sensors arranged in the vertical direction from the top to the bottom of the hot water storage tank, heating means for heating hot water in the hot water storage tank to a high temperature, and a position lower than the outlet pipe of the hot water storage tank A medium-temperature water mixing valve that is connected and mixes a medium-temperature water discharge pipe that discharges medium-temperature water from the hot water storage tank, and high-temperature water from the discharge pipe and medium-temperature water from the medium-temperature water discharge pipe to form a mixed water of a set temperature. A hot water storage hot water supply apparatus comprising: a hot water temperature sensor provided between a hot water storage tank of the hot water hot water discharge pipe and a hot water mixing valve; and a time measuring means for counting time. The detected temperature is below the specified temperature And when the detected temperature of the hot water storage temperature sensor is below a predetermined temperature, and further stop time of the heating means performs the freeze prevention operation When equal to or more than a predetermined time.

  Further, in claim 5, an outside air temperature sensor for detecting the outside air temperature, a hot water storage tank in which a water supply pipe is connected to the lower end portion, and a hot water discharge pipe for discharging the hot water stored in the hot water is connected to the upper end portion. A plurality of hot water storage temperature sensors arranged in the vertical direction from the top to the bottom of the hot water storage tank, heating means for heating the hot water in the hot water storage tank to a high temperature, and detecting the temperature of the hot water heated by the heating means An outlet temperature sensor, a circulating pump for circulating hot water in the hot water storage tank to the heating means, a first heat pump return pipe communicating the outlet side of the heating means and the flow path switching means, the flow path switching means and the hot water storage A second heat pump return pipe communicating with the upper part of the tank, a bypass pipe having one end communicating with the flow path switching means and the other end branched to communicate with the water supply pipe and the hot water storage tank lower part, and a branch portion of the bypass pipe Salary A check valve provided on the pipe side, connected to a position lower than the hot water discharge pipe of the hot water storage tank, an intermediate hot water hot water discharge pipe for allowing the intermediate hot water to flow out of the hot water storage tank, hot water from the hot water discharge pipe and the intermediate hot water A medium-temperature water mixing valve that mixes medium-temperature water from a tapping pipe into a set temperature mixed water, a medium-temperature water temperature sensor provided between a hot water storage tank of the medium-temperature water tapping pipe and a medium-temperature water mixing valve, A hot water mixing valve that mixes the mixed water from the intermediate temperature water mixing valve with the water supplied from the first water supply bypass pipe branched from the water supply pipe and supplies hot water from the hot water tap as hot water at a hot water set temperature; and the intermediate temperature water mixing valve; Branches from the hot water supply pipe between the hot water supply mixing valve, mixes the mixed water from the intermediate hot water mixing valve and the water supply from the second water supply bypass pipe branched from the water supply pipe, and fills the hot water as hot water at the bath set temperature With a bath mixing valve that fills the bathtub through a pipe In the hot water storage type hot water supply apparatus, when the temperature detected by the outside air temperature sensor is equal to or lower than a predetermined temperature and the temperature detected by a hot water storage temperature sensor near one end of the intermediate temperature hot water discharge pipe is lower than the predetermined temperature, The freeze prevention operation is performed when the temperature detected by the medium temperature water temperature sensor falls below a predetermined temperature.

  According to a sixth aspect of the present invention, the freeze prevention operation is performed when the flow path switching means is set to the bypass pipe side, the circulation pump and the heating means are driven, and the temperature detected by the outlet temperature sensor becomes equal to or higher than a predetermined temperature. Set the path switching means to the second heat pump return pipe, and when the temperature detected by the hot water storage temperature sensor exceeds the specified temperature, stop the circulation pump and heating means and set the flow path switching means to the bypass pipe side. Is to end.

  According to claim 1 of the present invention, when the temperature detected by the outside air temperature sensor is equal to or lower than the predetermined temperature and the temperature detected by the hot water storage temperature sensor is equal to or lower than the predetermined temperature, the temperature detected by the intermediate hot water temperature sensor is equal to or lower than the predetermined temperature. Since the freezing prevention operation is performed at this point, it is possible to prevent the parts and piping around the hot water storage tank and the middle temperature hot water discharge pipe from freezing.

  According to the second aspect, when the temperature detected by the outside air temperature sensor is equal to or lower than the predetermined temperature and the temperature detected by the hot water storage temperature sensor is equal to or lower than the predetermined temperature, and when the stop time of the hot water supply flow rate counter exceeds the predetermined time. Since the anti-freezing operation is performed, it is possible to prevent the useless anti-freezing operation when the piping temperature rises and there is no fear of freezing due to the hot water supply operation.

  According to the third aspect, when the temperature detected by the outside air temperature sensor is equal to or lower than the predetermined temperature and the temperature detected by the hot water storage temperature sensor is equal to or lower than the predetermined temperature, and further, when the stop time of the bath flow counter becomes equal to or longer than the predetermined time. Since the freeze prevention operation is performed, it is possible to prevent the use of the unnecessary freeze prevention operation when the temperature of the pipe rises and there is no fear of freezing due to the bath filling operation.

  According to the fourth aspect of the present invention, when the temperature detected by the outside air temperature sensor is equal to or lower than the predetermined temperature and the temperature detected by the hot water storage temperature sensor is equal to or lower than the predetermined temperature, the heating means is further frozen when the stop time is longer than the predetermined time. Since the prevention operation is performed, it is possible to prevent the use of the freeze prevention operation when the pipe temperature rises due to the operation of the heating means and there is no fear of freezing.

  According to claim 5, when the temperature detected by the outside air temperature sensor is equal to or lower than the predetermined temperature and the temperature detected by the hot water storage temperature sensor in the vicinity where one end of the intermediate temperature hot water discharge pipe is connected is equal to or lower than the predetermined temperature, Freezing prevention operation is performed when the temperature detected by the medium temperature water temperature sensor falls below the specified temperature, so it is possible to accurately determine the state in which freezing cannot be prevented by heat dissipation from the hot water in the hot water storage tank. It is possible to prevent the piping from freezing and to prevent unnecessary freezing prevention operation.

  According to the sixth aspect of the present invention, the freeze prevention operation is performed when the flow path switching unit is set to the bypass pipe side and the circulation pump and the heating unit are driven, and the temperature detected by the outlet temperature sensor becomes equal to or higher than a predetermined temperature. Set the flow path switching means to the second heat pump return pipe, stop the circulation pump and heating means when the temperature detected by the hot water storage temperature sensor exceeds the predetermined temperature, and set the flow path switching means to the bypass pipe side Since the operation is terminated, the freezing of the pipe connected to the heating means can be prevented by setting the flow path switching means on the bypass pipe side and driving the circulation pump and the heating means, and further the outlet temperature sensor detects When the temperature exceeds the predetermined temperature, the flow path switching means is set to the second heat pump return pipe, and the hot water storage tank is driven by driving the circulation pump and the heating means until the temperature detected by the hot water temperature sensor exceeds the predetermined temperature. One in which it is possible to prevent freezing of the peripheral piping and components.

BRIEF DESCRIPTION OF THE DRAWINGS Schematic of the hot water storage type hot water supply apparatus which shows one Embodiment of this invention. The flowchart figure of the freezing prevention driving | operation.

Next, a hot water storage type hot water supply apparatus according to the present invention will be described with reference to an embodiment shown in the drawings.
This hot water storage type hot water supply device is used to boil hot water and store hot water in the midnight hours when the unit price of contracted electricity by time zone is low, and to use this hot water for hot water supply. In addition, indirect heat with hot water in the hot water storage can It is equipped with a hot water tank 2 for storing hot water, with a bath circuit for replenishing or keeping warm water in the bathtub and replacing the hot water in the hot water storage can directly into the bathtub. A hot water storage tank unit, 3 is a heat pump unit as a heating means for heating the hot water in the hot water storage tank 2, 4 is a hot water tap provided in a kitchen or a washroom, and 5 is a hot water remote controller provided near the hot water tap 4 , 6 is a bathtub, and 7 is a bath remote control provided in the bathroom.

  The hot water storage tank 2 of the hot water storage tank unit 1 has a hot water discharge pipe 8 connected to the upper end, a water supply pipe 9 connected to the lower end, a heat pump forward pipe 10 constituting a heat pump circulation circuit in the lower part, and a heat pump circulation circuit in the upper part. The heat pump return pipe 11 is connected, the hot water in the hot water storage tank 2 taken out from the heat pump forward pipe 10 is boiled by the heat pump unit 3 and returned to the hot water storage tank 2 from the heat pump return pipe 11 to be stored in the hot water supply pipe 9. The hot water in the hot water storage tank 2 is pushed up by the water supply from the hot water, and the hot water in the upper part of the hot water storage tank 2 is pushed out from the hot water discharge pipe 8 to supply hot water.

The heat pump unit 3 includes a compressor 12, a water heat exchanger 13 as a condenser, an electronic expansion valve 14 as a pressure reducer, and a forced air-cooled evaporator 15. A heat pump circulation pump 17 that circulates hot and cold water to the water heat exchanger 13 through the heat pump forward pipe 10 and the heat pump return pipe 11 and a heat pump control unit 18 that controls the driving of the heat pump are provided. Is a supercritical heat pump cycle using carbon dioxide as a refrigerant.
Since carbon dioxide is used as the refrigerant, low-temperature water can be boiled up to a high temperature of about 90 ° C. without an electric heater.

  Here, the water heat exchanger 13 adopts a counter flow system in which the refrigerant and hot water in the hot water storage tank 2 that is heated water face each other. In the supercritical heat pump cycle, the refrigerant is Since the water to be heated can be efficiently heated to a high temperature because it is condensed in a supercritical state, the temperature difference between the water heat exchanger 13 inlet temperature and the refrigerant outlet temperature is constant. By controlling the electronic expansion valve 14 or the compressor 12, the water to be heated is heated in a state where the COP is very good when the inlet temperature of the water heat exchanger 13 of the water to be heated is a low temperature of about 5 to 20 ° C. It is possible to do.

Reference numeral 19 denotes a bath heat exchanger made of a stainless steel tube for heating the hot water in the bathtub 6, which is provided in an almost middle portion of the hot water storage tank 2. A bath return pipe 22 having a bath outlet pipe 20 and a bath circulation pump 21 is connected so that hot water in the bathtub 6 can be circulated, and the hot water in the bathtub 6 is heated by the high-temperature water in the hot water storage tank 2 to be kept warm. A chasing is done.
Reference numeral 23 denotes a bath temperature sensor for detecting the temperature of hot water in the bathtub 6 circulating through the bath return pipe 22.

  Reference numeral 24 denotes an intermediate temperature hot water discharge pipe, one end of which is lower than the hot water discharge pipe 8 and is connected to an intermediate position facing the bath heat exchanger 19 on the side wall of the hot water storage tank 2. The hot water stored at the intermediate position of the hot water storage tank 2 such as the intermediate temperature water whose temperature has been lowered by the heat exchange with the hot water and the boundary layer of the hot water and water is lowered from the hot water tank 2. is there.

  25 is an intermediate hot water mixing valve composed of an electric mixing valve for mixing hot water from the hot water discharge pipe 8 and intermediate temperature water from the intermediate hot water hot water discharge pipe 24, and 26 is an intermediate hot water supply pipe 27 downstream of the intermediate hot water mixing valve 25. The hot water supply setting set by the user using the hot water remote controller 5 or the bath remote controller 7 for the hot water from the hot water pipe 8 connected to the upper end of the hot water storage tank 2 and the intermediate temperature water near the intermediate position of the hot water storage tank 2 The mixing ratio is controlled so that the mixing target temperature is higher than the temperature by a predetermined temperature.

  Reference numeral 28 denotes a hot water mixing valve composed of an electric mixing valve that mixes hot water from the intermediate hot water mixing valve 25 and low temperature water from the first water supply bypass pipe 29 branched from the water supply pipe 9, and a hot water supply pipe 30 downstream thereof. The mixing ratio is controlled so that the hot water temperature detected by the hot water supply temperature sensor 31 provided at the hot water supply remote controller 5 or the bath remote controller 7 becomes the hot water supply set temperature set by the user.

  32 is a bath mixing system composed of an electric mixing valve that mixes hot water from the branch intermediate hot water pipe 33 branched from the intermediate hot water pipe 27 and low temperature water from the second water supply bypass pipe 34 branched from the water supply pipe 9. The bath setting set by the user using the hot water remote controller 5 or the bath remote controller 7 is the hot water temperature detected by the hot water temperature sensor 36 provided in the hot water pipe 35, which is a valve and is trained in the bath return pipe 22 on the downstream side. The mixing ratio is controlled so that the temperature is reached.

  The hot water filling pipe 35 is provided with a hot water filling valve 37 for starting and stopping hot water filling to the bathtub 6 and a bath flow rate counter 38 for counting the amount of hot water filling to the bathtub 6. .

  A plurality of hot water storage temperature sensors 39 are arranged in the vertical direction from the top to the bottom of the hot water storage tank 2. In this embodiment, five temperature sensors 39a, 39b, 39c, 39d, 39e are arranged. Based on the detected temperature information, the amount of heat remaining in the hot water storage tank 2 is detected, and the temperature distribution in the vertical direction in the hot water storage tank 2 and the remaining amount of medium temperature water are detected.

  The hot water remote controller 5 and the bath remote controller 7 are respectively provided with a hot water supply temperature setting switch 40 for setting a hot water supply set temperature and a bath temperature setting switch 41 for setting the bath set temperature, and a bath set temperature for the bathtub 6. Are provided with an automatic bath switch 42 that fills the hot water by a hot water filling amount set by a hot water filling amount setting switch (not shown) of the bath remote control 7 and keeps it warm for a predetermined time, and further from the second water supply bypass pipe 34. Is provided with a water supply switch 43 that supplies the water supply to the bathtub 6 through the hot-water pipe 35 to lower the temperature of the bathtub water.

Reference numeral 44 denotes a control unit having a microcomputer that receives the input of each sensor in the hot water storage tank unit 1 and controls the drive of each actuator, and includes a time measuring means (not shown).
The hot water remote controller 5 and the bath remote controller 7 are connected to the control unit 44 by radio or wire so that a user can set an arbitrary hot water set temperature and bath set temperature.

  The control unit 44 sets the valve opening degree of the intermediate temperature water mixing valve 25 so that the temperature detected by the intermediate temperature sensor 26 becomes a mixing target temperature that is higher by a predetermined temperature than the higher one of the hot water supply set temperature or the bath set temperature. In addition to feedback control, the valve opening of the hot water mixing valve 28 is feedback controlled so that the temperature detected by the hot water temperature sensor 31 becomes the hot water set temperature. The valve opening degree of the bath mixing valve 32 is feedback-controlled so that the temperature detected by the temperature sensor 36 becomes the bath set temperature.

  The control unit 44 is set so that the control response speed of the intermediate hot water mixing valve 25 is slower than the control response speed of the hot water supply mixing valve 28. The control response speed of the feedback control of the hot water supply mixing valve 28 is superior, and the overshoot or undershoot of the hot water supply temperature can be greatly reduced.

  In addition, the controller 44 determines whether there is medium temperature water in the hot water storage tank 2 when the water supply switch 43 is pressed and the water supply operation is instructed in the hot water storage tank 2 or in the hot water storage operation. 39 is determined based on whether the temperature detected by the hot water storage temperature sensors 39b to 39d facing the bath heat exchanger 19 is less than 30 ° C. The medium temperature water less than 30 ° C. depends on the bath water temperature. Is a temperature at which the temperature of the bath water can be lowered somehow, and if it is higher than this, the temperature does not decrease easily even if the middle temperature water is poured in, and the control unit 44 has the medium temperature water less than 30 ° C. The hot water bath apparatus is used to improve the COP of the hot water bath apparatus while draining hot water instead of water into the bathtub 6 and eliminating the problem of sudden drop in temperature or cold water directly hitting the bather.

  45 is a relief valve for releasing the overpressure in the hot water storage tank 2, 46 is a pressure reducing valve for reducing the pressure of the water supply, 47 is a hot water flow rate counter for counting the amount of hot water to be supplied, and 48 is for the hot water in the bathtub 6 to flow backward. Two check valves 49 provided to prevent this are provided as a feed water temperature sensor for detecting the feed water temperature.

  Reference numeral 50 denotes a flow path switching means comprising a three-way valve provided in the middle of the heat pump return pipe 11, and hot water from the first heat pump return pipe 11a on the heat pump side is allowed to flow to the second heat pump return pipe 11b on the tank side, or a hot water storage tank 2 When switching to the bypass pipe 51 communicating with the lower part and the water supply pipe 9, the circulation pump is provided when a freezing danger temperature is detected by an outside air temperature sensor 52 provided on the windward side of the evaporator 15 to measure the outside air temperature. 17 is driven, and the flow path switching unit 50 circulates the flowing water from the first heat pump return pipe 11a to the bypass pipe 51 side, and circulates from the lower part of the hot water storage tank 2 to the water refrigerant heat exchanger 13 through the heat pump forward pipe 10. By repeatedly preventing freezing, the hot water in the lower part of the hot water storage tank 2 is circulated through the water / refrigerant heat exchanger 13 by driving the heat pump unit 3. At the start of the boiling operation, if the outlet temperature sensor 53 of the water-refrigerant heat exchanger 5 detects a predetermined temperature in order to prevent the low-temperature water that has not yet risen in temperature from being mixed with the high-temperature water in the upper part of the hot water storage tank 2, The flow path is switched so that the hot water from the first heat pump return pipe 11a flows for the first time to the second heat pump return pipe 11b side.

  A check valve 54 is provided in the middle of a bypass pipe 51 that connects the flow path switching means 50 to the lower part of the hot water storage tank 2 and the water supply pipe 9, and is located closer to the water supply pipe 9 than the connecting part with the lower part of the hot water storage tank 2. The hot water in the hot water storage tank 2 and the bypass pipe 51 is prevented from flowing back to the water supply side.

  55 is a medium temperature water temperature sensor provided between the hot water storage tank 2 of the intermediate temperature hot water discharge pipe 24 and the intermediate temperature water mixing valve 24 and detects the temperature of the medium temperature water in the hot water storage tank 2.

Next, the freeze prevention operation in the hot water storage type hot water supply apparatus of this embodiment will be described with reference to the flowchart shown in FIG.
First, the control unit 44 determines whether the detected temperature of the outside air temperature sensor 52 provided on the windward side of the evaporator 15 is lower than the freezing danger temperature, in this embodiment, the detected temperature is lower than −5 ° C. (S1) When the temperature detected by the outside air temperature sensor 52 is lower than −5 ° C., the temperature of the can at the position where one end of the intermediate temperature hot water discharge pipe 24 is connected next is the predetermined temperature. It is determined whether the temperature detected by the hot water storage temperature sensor 39c is lower than 40 ° C. in this embodiment (S2), and the temperature detected by the outside air temperature sensor 52 is a predetermined temperature that is lower than the freezing danger temperature and the hot water storage tank. When the temperature of the can body at a position to which one end of the intermediate temperature hot water discharge pipe 24 is connected is lower than a predetermined temperature, the control unit 44 determines whether or not the freeze prevention operation is performed. (S3)

  First, the control unit 44 determines whether the temperature of the medium-temperature water detected by the medium-temperature water temperature sensor 55 is a predetermined temperature, which is lower than 0 ° C. in this embodiment (S4), and the temperature of the medium-temperature water is less than 0 ° C. When the temperature is low, freezing prevention operation is performed (S5), and when the temperature of the intermediate temperature water is 0 ° C. or higher, the hot water flow rate counter 7 does not count the hot water to supply hot water for a predetermined time or longer. Judge whether it is 2 hours or more. (S6)

  In (S6), when the hot water flow rate counter 7 does not count the hot water supplied for 2 hours or longer, the freeze prevention operation is performed (S5). It is determined whether or not the predetermined time is not less than a predetermined time, and in this embodiment, not less than 2 hours. (S7)

  When the time during which the bath flow counter 38 does not count hot water is 2 hours or more in (S7), the freeze prevention operation is performed (S5). Next, when the time is less than 2 hours, the time when the heat pump unit 3 is not operated is a predetermined time. As described above, in this embodiment, it is determined whether it is 2 hours or more. (S8)

  When the time when the heat pump unit 3 is not operated is 2 hours or more in (S8), the freeze prevention operation is performed (S5), and when it is less than 2 hours, it is determined that the freeze prevention operation is not necessary and the next freeze prevention operation is not performed. (S9) and return to (S1).

When the anti-freezing operation is performed in (S5), the flow path switching means 50 is set to the bypass pipe 51 side (S10), and then the compressor 12 and the heat pump circulation pump 17 of the heat pump unit 3 are set. Turn on. (S11)
As a result, the flow path switching means 50 repeatedly circulates the flowing water from the first heat pump return pipe 11a to the bypass pipe 51 side and returns from the lower part of the hot water storage tank 2 to the water / refrigerant heat exchanger 13 through the heat pump forward pipe 10 to the heat pump. This prevents the pipes connected to the unit 3 from freezing.

When the detected temperature of the outlet temperature sensor 53 of the water / refrigerant heat exchanger 5 reaches a predetermined temperature in the state of (S11), which is 50 ° C. or higher in this embodiment (S12), the flow path switching means 50 is bypassed. From the 51st side, it sets to the 2nd heat pump return pipe 11b side. (S13)
As a result, hot water at a high temperature is supplied to the upper part of the hot water storage tank 2 to prevent the piping and parts around the hot water storage tank 2 from freezing.

  Then, the temperature of the can at the position where one end of the intermediate temperature hot water discharge pipe 24 of the hot water storage tank 2 is connected is higher than a predetermined temperature. In this embodiment, the temperature detected by the hot water storage temperature sensor 39c is 45 ° C. or higher. If it becomes (S14), the control part 44 will judge that there is no possibility of freezing, and the compressor 12 and the heat pump circulation pump 17 of the heat pump unit 3 are turned off (S15), and the flow path switching means 50 is made into the 2nd heat pump return pipe 11b. From the side to the bypass pipe 51 side (S16), thereby terminating the freeze prevention operation (S17) and returning to (S1).

  As described above, the temperature of the can body at the position where the temperature of the outside air temperature sensor 52 is lower than the predetermined freezing temperature and the temperature of the hot water storage tank 2 is connected to one end of the hot water discharge pipe 24 is higher than the predetermined temperature. When the temperature is low, the control unit 44 determines whether or not the anti-freezing operation is performed. Further, when the temperature of the medium-temperature water detected by the medium-temperature water temperature sensor 55 is lower than the predetermined temperature, the control unit 44 performs the anti-freezing operation. It is possible to prevent the pipes connected to the heat pump unit 3 and the pipes and parts around the hot water storage tank 2 from being frozen without performing a freezing prevention operation.

  In addition, the temperature detected by the outside air temperature sensor 52 is a predetermined temperature lower than the freezing temperature, and the temperature of the can at the position where one end of the intermediate temperature hot water discharge pipe 24 of the hot water storage tank 2 is connected is lower than the predetermined temperature. When there is no predetermined time, a freeze prevention operation is performed. Therefore, a wasteful freeze prevention operation is performed in consideration of a hot water supply operation, a bath filling operation or a reheating operation, or a rise in piping temperature due to the operation of the heat pump unit 3. Without being performed, the pipes connected to the heat pump unit 3 and the pipes and parts around the hot water storage tank 2 can be prevented from freezing.

  In the freeze prevention operation, first, the flow path switching means 50 is set to the bypass pipe 51 side, and then the compressor 12 and the heat pump circulation pump 17 of the heat pump unit 3 are turned on, and the flowing water from the first heat pump return pipe 11a is turned on. Is flown to the bypass pipe 51 side, the circulation returning from the lower part of the hot water storage tank 2 to the water / refrigerant heat exchanger 13 through the heat pump forward pipe 10 is repeated to prevent freezing of the pipes connected to the heat pump unit 3, When the detected temperature of the outlet temperature sensor 53 of the refrigerant heat exchanger 5 becomes equal to or higher than a predetermined temperature, the flow path switching means 50 is set from the bypass pipe 51 side to the second heat pump return pipe 11b side, and placed above the hot water storage tank 2. Since hot water is supplied at a high temperature to prevent freezing of pipes and parts around the hot water storage tank 2, it is connected to the heat pump unit 3 in a single freeze prevention operation. And has piping and freezing of the hot water storage tank 2 around pipes and components are those that can be prevented.

2 Hot water storage tank 3 Heating means 8 Hot water discharge pipe 9 Water supply pipe 24 Medium temperature hot water discharge pipe 25 Medium temperature water mixing valve 39 Hot water storage temperature sensor 52 Outside temperature sensor 55 Medium temperature water temperature sensor

Claims (6)

  An outside air temperature sensor for detecting the outside air temperature, a hot water storage tank connected to the lower end, a hot water storage tank connected to the upper end of the hot water stored in the hot water, and a top of the hot water storage tank A plurality of hot water storage temperature sensors arranged in the vertical direction from the top to the bottom, heating means for heating the hot water in the hot water storage tank to a high temperature, and a hot water storage medium hot water connected to a position lower than the outlet pipe of the hot water storage tank. A medium temperature water discharge pipe that flows out from the tank, a medium temperature water mixing valve that mixes high temperature water from the discharge pipe and medium temperature water from the medium temperature water discharge pipe to form a mixed water of a set temperature, and the medium temperature water discharge pipe In a hot water storage type hot water supply apparatus having an intermediate temperature water temperature sensor provided between a hot water storage tank and an intermediate temperature water mixing valve, the temperature detected by the outside air temperature sensor is lower than a predetermined temperature and detected by the hot water temperature sensor The measured temperature is below the specified temperature , Hot water storage type hot water supply apparatus temperature detected in medium-temperature water temperature sensor further is characterized by performing a freeze prevention operation When equal to or less than a predetermined temperature.   An outside air temperature sensor for detecting the outside air temperature, a hot water storage tank connected to the lower end, a hot water storage tank connected to the upper end of the hot water stored in the hot water, and a top of the hot water storage tank A plurality of hot water storage temperature sensors arranged in the vertical direction from the top to the bottom, heating means for heating the hot water in the hot water storage tank to a high temperature, and a hot water storage medium hot water connected to a position lower than the outlet pipe of the hot water storage tank. A medium temperature water discharge pipe that flows out from the tank, a medium temperature water mixing valve that mixes high temperature water from the discharge pipe and medium temperature water from the medium temperature water discharge pipe to form a mixed water of a set temperature, and the medium temperature water discharge pipe In a hot water storage type hot water supply apparatus comprising an intermediate temperature water temperature sensor provided between a hot water storage tank and an intermediate temperature water mixing valve, a hot water flow rate counter for counting the amount of hot water to be supplied, and a timing means for counting time. The outside temperature sensor The hot water storage system is characterized in that when the temperature detected by the hot water storage temperature sensor is lower than the predetermined temperature and the temperature detected by the hot water storage temperature sensor is lower than the predetermined temperature, the freeze prevention operation is performed when the stop time of the hot water supply flow rate counter exceeds the predetermined time. Hot water supply device.   An outside air temperature sensor for detecting the outside air temperature, a hot water storage tank connected to the lower end, a hot water storage tank connected to the upper end of the hot water stored in the hot water, and a top of the hot water storage tank A plurality of hot water storage temperature sensors arranged in the vertical direction from the top to the bottom, heating means for heating the hot water in the hot water storage tank to a high temperature, and a hot water storage medium hot water connected to a position lower than the outlet pipe of the hot water storage tank. A medium temperature water discharge pipe that flows out from the tank, a medium temperature water mixing valve that mixes high temperature water from the discharge pipe and medium temperature water from the medium temperature water discharge pipe to form a mixed water of a set temperature, and the medium temperature water discharge pipe To a hot water storage type hot water supply apparatus equipped with an intermediate temperature water temperature sensor provided between the hot water storage tank and an intermediate temperature water mixing valve, a bath flow rate counter for counting the amount of hot water filled in the bathtub, and a time measuring means for counting time In the outside temperature sensor The hot water storage system is characterized in that when the temperature detected by the hot water storage temperature sensor is lower than the predetermined temperature and the temperature detected by the hot water storage temperature sensor is lower than the predetermined temperature, the freeze prevention operation is performed when the stop time of the bath flow counter becomes longer than the predetermined time. Hot water supply device.   An outside air temperature sensor for detecting the outside air temperature, a hot water storage tank connected to the lower end, a hot water storage tank connected to the upper end of the hot water stored in the hot water, and a top of the hot water storage tank A plurality of hot water storage temperature sensors arranged in the vertical direction from the top to the bottom, heating means for heating the hot water in the hot water storage tank to a high temperature, and a hot water storage medium hot water connected to a position lower than the outlet pipe of the hot water storage tank. A medium temperature water discharge pipe that flows out from the tank, a medium temperature water mixing valve that mixes high temperature water from the discharge pipe and medium temperature water from the medium temperature water discharge pipe to form a mixed water of a set temperature, and the medium temperature water discharge pipe In a hot water storage hot water supply apparatus comprising an intermediate temperature water temperature sensor provided between the hot water storage tank and the intermediate temperature water mixing valve and a time measuring means for counting time, the temperature detected by the outside air temperature sensor is a predetermined temperature. Below and hot water temperature sensor When the detected temperature is below a predetermined temperature, further hot water storage type water heater stop time of the heating means and performing freeze prevention operation When equal to or more than a predetermined time.   An outside air temperature sensor for detecting the outside air temperature, a hot water storage tank connected to the lower end, a hot water storage tank connected to the upper end of the hot water stored in the hot water, and a top of the hot water storage tank A plurality of hot water storage temperature sensors arranged in the vertical direction below, a heating means for heating the hot water in the hot water storage tank to a high temperature, an outlet temperature sensor for detecting the temperature of the hot water heated by the heating means, A circulation pump that circulates hot water in the hot water storage tank to the heating means, a first heat pump return pipe that communicates the outlet side of the heating means and the flow path switching means, and a first heat pump that communicates the flow path switching means and the upper portion of the hot water storage tank. Two heat pump return pipes, a bypass pipe having one end communicating with the flow path switching means and the other end branching to communicate with the water supply pipe and the lower part of the hot water storage tank, and a reverse provided on the water supply pipe side with respect to the branch portion of the bypass pipe Stop valve The hot water storage tank is connected to a position lower than the hot water discharge pipe and mixes hot water from the hot water discharge pipe with high temperature water from the hot water discharge pipe and intermediate hot water from the hot water discharge pipe. A medium temperature water mixing valve to be mixed water at a set temperature, a medium temperature water temperature sensor provided between the hot water storage tank of the medium temperature water discharge pipe and the medium temperature water mixing valve, and the mixed water from the medium temperature water mixing valve; A hot water mixing valve that mixes the water supplied from the first water supply bypass pipe branched from the water supply pipe and supplies hot water from the hot water tap as hot water at a hot water set temperature, and a hot water pipe between the intermediate hot water mixing valve and the hot water mixing valve The mixture water from the intermediate hot water mixing valve and the water supply from the second water supply bypass pipe branched from the water supply pipe are mixed to fill the bathtub as hot water at the set temperature of the bath through the hot water pipe. In a hot water storage system with a bath mixing valve When the temperature detected by the outside air temperature sensor is equal to or lower than the predetermined temperature and the temperature detected by the hot water storage temperature sensor near one end of the intermediate temperature hot water discharge pipe connected is equal to or lower than the predetermined temperature, further detection by the intermediate temperature water temperature sensor A hot water storage type hot-water supply apparatus that performs anti-freezing operation when the measured temperature falls below a predetermined temperature.   In the anti-freezing operation, the flow path switching means is set on the bypass pipe side to drive the circulation pump and the heating means, and when the temperature detected by the outlet temperature sensor exceeds a predetermined temperature, the flow path switching means is set to the second heat pump. It is set in the return pipe, and when the temperature detected by the hot water storage temperature sensor exceeds a predetermined temperature, the circulation pump and the heating means are stopped, the flow path switching means is set to the bypass pipe side, and the operation is ended. The hot water storage type hot water supply apparatus according to claim 5.

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