JP2005134077A - Hot water storage type water heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize a hot water storage type water heater capable of saving energy and reducing the maintenance cost by providing both a water heater using solar heat and a water heater composed of a heat pump cycle. <P>SOLUTION: This hot water storage type water heater comprises a solar heat collector 12; a first hot water storage tank 11 connected to a water feeding pipe 13 to store hot water heated by the heat collector 12; a second hot water tank 21 for storing hot water;, a heat pump unit 22 composed of the heat pump cycle to circulate and boil up hot water in the second hot water storage tank 21; and a hot water switching device 30 connected to delivery pipes 16 and 26 of the first tank 11 and the second tank 21 to supply at least either the hot water supplied from the first tank 11 and the hot water supplied from the second tank 21 based on the temperature of the hot water stored in the first tank 11. According to such a structure, the energy can be saved, and the maintenance cost can be reduced. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  TECHNICAL FIELD The present invention relates to a hot water storage hot water supply apparatus including a first hot water storage tank that stores hot water heated by a heat source device that includes a heat pump cycle, and more particularly to a second hot water storage tank that stores hot water heated by solar heat. The present invention also relates to a hot water supply apparatus for discharging hot water from either one of the hot water storage tanks.

  Conventionally, as a hot water storage type hot water supply apparatus using solar heat, for example, as shown in Patent Document 1, a solar heat collector, a blowing means, a heat pump circuit having a variable capacity compressor, and a solar heat collector are passed. Heat pump circuit evaporator that exchanges heat with air, collector inlet air temperature sensor, evaporator outlet air temperature sensor, and compressor so that the evaporator outlet air temperature is substantially the same as the collector inlet air temperature The compressor function variable control means for setting the rotation speed of the engine, and on a sunny day with good weather, the evaporation temperature is supplied by supplying high-temperature air that has received solar heat from the solar heat collector to the evaporator. This increases the efficiency of the heat pump cycle.

Further, on a cloudy day or a rainy day when the weather is bad, the compression function force variable control means is configured to operate the compressor according to a preset compressor rotation speed. As a result, even when the amount of solar radiation is small or not at all, it is possible to operate the compressor by setting the number of revolutions of the compressor in the optimum state with the required heating capacity and efficiency, so the heating capacity of the heat pump circuit is reduced. The heating operation is ensured and efficient (see, for example, Patent Document 1).
JP 2002-286323 A

  However, according to the above-mentioned Patent Document 1, solar heat is converted into warm air applied to the evaporator to reduce the size of the evaporator to improve the efficiency of the heat pump cycle, and the rotation of the compressor even when there is no solar radiation. By changing the number and making the above efficient heating operation save energy and low maintenance costs, it is configured as a hot water storage type hot water supply device that stores hot hot water in the midnight hours when the electricity rate is the cheapest In the heat source device comprising a heat pump cycle, there is a problem that solar heat cannot be used for operation in the midnight time zone where there is no solar radiation.

  In addition, since this type of hot water storage type hot water supply device is configured to store hot hot water in the upper part of the hot water storage tank and to discharge hot water from this portion, tap water from the lower side every time the upper hot water is discharged. Is being supplied with water. Accordingly, the hot water temperature in the vicinity of the central portion of the hot water storage tank decreases with time (this is referred to as medium hot water). When it is determined that the amount of stored hot water is insufficient with respect to the expected hot water supply load at this time, the heat source device is heated. In such a case, there is a problem that the feed water temperature sucked into the heat source device is higher than the tap water, so that the efficiency of the heat pump cycle is lowered.

  In view of the above, an object of the present invention is to provide a hot water storage type hot water supply apparatus that can achieve energy saving and low maintenance cost by providing a hot water supply apparatus that uses solar heat and a hot water supply apparatus that includes a heat pump cycle. There is.

  In order to achieve the above object, the technical means according to claims 1 to 7 are employed. That is, in the invention according to claim 1, hot water supply water connected to the solar heat collector (12) and the water supply means (13) for supplying hot water tap water and heated by the solar heat collector (12). A first hot water storage tank (11) for storing hot water, a second hot water storage tank (21) which is installed in parallel with the first hot water storage tank (11) and stores hot water, and a heat pump cycle. The first hot water storage is connected to a heat source device (22) that circulates the hot water supply water and performs a boiling operation, and a hot water supply hot water discharge circuit (16, 26) of the first hot water storage tank (11) and the second hot water storage tank (21). Based on the hot water temperature stored in the tank (11), at least one hot water discharged from the first hot water storage tank (11) and hot water discharged from the second hot water storage tank (21) is discharged. Hot water supply switching device (30 It is characterized by having and.

  According to invention of Claim 1, based on the hot water temperature of the hot water stored in the 1st hot water storage tank (11), the hot water discharged from the 1st hot water storage tank (11) and the 2nd hot water storage tank (21 ) By supplying a hot water supply switching device (30) for discharging at least one hot water supplied from the hot water, the hot water heated by the solar heat collector (12) is discharged on a sunny day. As a result, the total operating time for boiling the heat source device (22) is greatly shortened, so that energy saving and low maintenance costs can be achieved. In addition, on hot days when solar heat cannot be used, the hot water heated by the heat source device (22) composed of the heat pump cycle can be discharged, so the comfort in the hot water supply function is not impaired.

  In the invention described in claim 2, when the hot water temperature of the hot water stored in the first hot water storage tank (11) is higher than the required hot water temperature, the hot water switching device (30) ) Side hot water supply is controlled to discharge. According to the second aspect of the invention, specifically, the total operation time for boiling of the heat source device (22) can be shortened by preferentially discharging hot water on the first hot water storage tank (11) side.

  In the invention according to claim 3, the hot water supply switching device (30) is such that the hot water temperature of the hot water stored in the first hot water storage tank (11) is higher than the temperature of the tap water supplied from the water supply means (13). And when the temperature is lower than the required hot water supply temperature, the hot water supply on the first hot water storage tank (11) side and the second hot water storage tank (21) are controlled to discharge. According to the third aspect of the invention, since the amount of hot water supplied from the second hot water storage tank (21) can be reduced, the total operation time for boiling the heat source device (22) can be shortened.

  In the invention according to claim 4, the hot water supply switching device (30) is such that the hot water temperature of the hot water stored in the first hot water storage tank (11) is lower than the temperature of the tap water supplied from the water supply means (13). In some cases, the hot water supply water on the second hot water storage tank (21) side is controlled to be discharged. According to the invention described in claim 4, it is possible to easily detect a bad day when solar heat cannot be used and that the hot water supply device using solar heat is stopped, and at the heat source device (22). Since the heated hot water can be discharged, the comfort in the hot water supply function is not impaired.

  In the fifth aspect of the present invention, the hot water supply switching device (30) includes at least one of hot water discharged from the first hot water storage tank (11) and hot water discharged from the second hot water storage tank (21). And hot water mixing means (33) for adjusting the required hot water supply temperature by mixing tap water supplied from the water supply means (13).

  According to the fifth aspect of the present invention, if the hot water temperature in the hot water storage tank (11, 21) is equal to or higher than the required hot water temperature, the stored hot water can be used up. Therefore, in the heat source device (22) in which the hot water use amount for the day is set in advance and the heating operation is performed in the midnight time zone where the power rate is low, the operation time for boiling is reduced in addition to the midnight time zone. be able to. As a result, energy saving and low maintenance costs can be achieved.

  According to the sixth aspect of the present invention, the medium hot water supply means (18) for supplying hot water in the second hot water storage tank (21) to the first hot water tank (11) and the first hot water storage tank (11). Heat collection control means (15) for performing control to circulate the hot water supply water in the solar heat collector (12) and store hot water heated in the solar heat collector (12) in the first hot water storage tank (11) The heat collection control means (15) stops the water supply from the water supply means (13) when the hot water in the second hot water storage tank (21) reaches a predetermined medium temperature water region. Control is performed so that the medium-temperature water is supplied from the medium-temperature water supply means (18).

  According to the sixth aspect of the present invention, hot water in the second hot water storage tank (21) is supplied to the first hot water storage tank (11) side, thereby supplying water to the second hot water storage tank (21) side. Since water is supplied, the efficiency of the heat pump cycle can be improved by inhaling and operating tap water whose hot water temperature is lower than that of hot water of medium temperature water when the heat source device (22) is in a boiling operation.

  In a seventh aspect of the invention, the heat source device (22) is a heat pump cycle in which carbon dioxide is used as a refrigerant. According to the invention described in claim 7, since the heat source device (22) using carbon dioxide is a supercritical heat pump cycle, the hot water can be heated to a high temperature (for example, about 85 to 90 ° C.) and is well known. The second hot water storage tank (21) can be made smaller and more economical than the heat pump cycle using the refrigerant of chlorofluorocarbon or chlorofluorocarbon alternative.

  In addition, the code | symbol in the bracket | parenthesis of each said means shows a corresponding relationship with the specific means of embodiment mentioned later.

(First embodiment)
Hereinafter, a hot water storage type hot water supply apparatus according to a first embodiment of the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is a schematic diagram showing the overall configuration of a hot water storage type hot water supply apparatus. As shown in FIG. 1, the hot water storage type hot water supply apparatus of the present embodiment is a hot water supply boiled up by a solar hot water supply apparatus 10 for discharging hot water heated by solar heat and a heat pump unit 22 which is a heat source apparatus comprising a heat pump cycle. It comprises a heat pump hot water supply device 20 that discharges water and a hot water supply switching device 30 that outputs at least one of the hot water supply devices 10 and 20.

  The solar water heater 10 includes a first hot water storage tank 11, a solar heat collector 12 installed on the roof of a building, and the water circuit that is circulated from the first hot water storage tank 11 to the solar heat collector 12 and returned to the first hot water storage tank 11. And a heat collection control device 15 as heat collection control means. The first hot water storage tank 11 is a metal (for example, stainless steel) tank having excellent corrosion resistance, and a heat insulating material (not shown) is disposed on the outer peripheral portion, and hot water heated by solar heat is supplied for a long time. You can keep warm.

  The first hot water storage tank 11 has a vertically long shape, and an introduction port 11a is provided on the bottom surface of the first hot water storage tank 11, and a water supply pipe 13 serving as a water supply means for introducing tap water into the first hot water storage tank 11 is provided in the introduction port 11a. It is connected. The feed water pipe 13 is provided with a feed water temperature sensor 13a which is a temperature detecting means, and outputs temperature information in the feed water pipe 13 to a hot water supply switching control device 35 which will be described later. The hot water supply switching control device 35 is electrically connected to a heat collection control device 15 described later, and outputs temperature information in the water supply pipe 13 to the heat collection control device 15 described later.

  On the other hand, a lead-out port 11b is provided at the uppermost part of the first hot water storage tank 11, and a lead-out pipe 16 that is a hot water supply / outflow circuit for discharging hot water in the first hot water storage tank 11 is connected to the lead-out port 11b. Has been. A hot water temperature sensor 11e for detecting the hot water temperature T2 in the first hot water storage tank 11 is provided in the vicinity of the outlet 11b, and the hot water temperature T2 information in the first hot water storage tank 11 will be described later. The data is output to the device 15.

  In addition, a suction port 11 c for sucking tap water in the first hot water storage tank 11 is provided in the vicinity of the introduction port 11 a, and hot water heated by a solar heat collector 12 is provided above the first hot water storage tank 11. A discharge port 11d for discharging water is provided. The suction port 11 c and the discharge port 11 d are connected to the circulating water circuit 17. The circulating water circuit 17 is provided with a circulating pump 17a that circulates the tap water sucked from the suction port 11c to the solar heat collector 12 and returns it to the discharge port 11d, and is controlled by a heat collection control device 15 described later. So that it is electrically connected.

  The solar heat collector 12 has a water circuit that is heated by solar radiation inside, and is heated by circulating tap water sucked from the suction port 11c. A water temperature sensor (not shown) for detecting the water temperature of the water circuit is provided, and the water temperature information of the solar heat collector 12 is output to the heat collection control device 15 described later.

  The heat collection control device 15 as heat collection control means is a microcomputer that controls the circulation pump 17a described above, and is electrically connected to a hot water supply switching control device 35 described later. Then, temperature information from a feed water temperature sensor 13a, a tapping temperature sensor 11e, a water temperature sensor (not shown), and an operation signal from an operation panel (not shown) are input.

  Next, the heat pump hot water supply device 20 is installed in parallel with the first hot water storage tank 11, and includes a second hot water storage tank 21 that stores hot water, a heat pump cycle, and circulates the hot water in the second hot water storage tank 21 to perform boiling operation. A heat pump unit 22 that is a heat source device, a circulating water circuit 23 that forms a water circuit that circulates the tap water sucked from the lower part of the second hot water storage tank 21 to the heat pump unit 22 and returns it to the upper part of the second hot water storage tank 21; The heat source control device 25 is configured.

  The second hot water storage tank 21 is a metal (for example, stainless steel) tank having excellent corrosion resistance, similar to the first hot water storage tank 11, and a heat insulating material (not shown) is disposed on the outer peripheral portion, so that hot hot water is supplied. It can be kept warm for a long time. The second hot water storage tank 21 has a vertically long shape, and an introduction port 21a is provided on the bottom surface thereof, and a water supply pipe 13 for introducing tap water into the second hot water storage tank 21 is connected to the introduction port 21a. .

  A pressure reducing check valve (not shown) is provided at the upper end of the water supply pipe 13 so as to adjust the water pressure of the introduced tap water to a predetermined pressure and to prevent the back flow of hot water in the case of water interruption. On the other hand, a lead-out port 21b is provided at the uppermost part of the second hot water storage tank 21, and a lead-out pipe 26, which is a hot water supply / outflow circuit for leading hot water in the second hot water storage tank 21, is connected to the lead-out port 21b. Has been.

  A discharge pipe provided with a relief valve (not shown) is connected in the middle of the route of the outlet pipe 26. When the pressure in the second hot water storage tank 21 rises above a predetermined pressure, the second hot water storage The hot water in the tank 21 is discharged to the outside so as not to damage the second hot water storage tank 21 and the like.

  A suction port 21 c for sucking tap water in the second hot water storage tank 21 is provided in the vicinity of the introduction port 21 a, and hot water in the second hot water storage tank 21 is placed above the second hot water storage tank 21. A discharge port 21d for discharging is provided. The suction port 21c and the discharge port 21d are connected by a circulating water circuit 23, and a part of the circulating water circuit 23 is disposed in a heat pump unit 22 that is a heat source device.

  In addition, a heat exchanger (not shown) is provided in a portion of the circulating water circuit 23 arranged in the heat pump unit 22, and tap water in the second hot water storage tank 21 sucked from the suction port 21c is used as a high-temperature refrigerant. Heated by heat exchange and returned to the second hot water storage tank 21 from the discharge port 21d, the hot water in the second hot water storage tank 21 can be boiled up.

  The heat pump unit 22 of the present embodiment is a supercritical heat pump composed of refrigerant functional parts that constitute a heat pump cycle such as a compressor, a condenser, a decompressor, and an evaporator (not shown). This supercritical heat pump refers to a heat pump cycle in which the refrigerant pressure on the high-pressure side becomes equal to or higher than the critical pressure of the refrigerant. For example, the heat pump cycle uses carbon dioxide, ethylene, ethane, nitrogen oxide, or the like as a refrigerant. Incidentally, according to the supercritical heat pump, hot water can be boiled at a higher temperature (for example, about 85 ° C. to 90 ° C.) than a general heat pump cycle.

  Further, the heat pump unit 22 is operated by a control signal from a heat source control device 25 described later, and outputs an operation state to the heat source control device 25. Furthermore, a hot water temperature sensor 21e for detecting the hot water temperature in the upper part of the second hot water storage tank 21 is provided on the upper outer wall surface of the second hot water storage tank 21, and temperature information of the hot water temperature derived from the outlet 21b. Is output to a heat source control device 25 described later.

  A plurality of water level thermistors (not shown) are arranged in the vertical direction on the outer wall surface of the second hot water storage tank 21 at substantially equal intervals, and temperature information at each water level filled in the second hot water storage tank 21 is obtained. It outputs to the heat source control apparatus 25 mentioned later. This is based on temperature information from a water level thermistor (not shown), and the temperature boundary position between the hot water heated in the upper part of the second hot water storage tank 21 and the water before being heated in the lower part of the second hot water storage tank 21. It can be detected.

  The heat source control device 25 is a microcomputer that controls the heat pump unit 22 described above, and is electrically connected to a hot water supply switching control device 35 described later. Then, temperature information from a feed water temperature sensor 13a, a tapping temperature sensor 21e, a water level thermistor (not shown), and an operation signal from an operation panel (not shown) are input.

  In addition, the heat pump unit 22 of the present embodiment performs a boiling operation in the midnight time zone (for example, 10:00 pm to 7:00 of the next morning) at which the power rate is the lowest, and the heating operation is performed in advance on the day. Hot hot water is stored in the second hot water storage tank 21 so that a hot water storage amount corresponding to the amount of hot water used can be secured. However, when the hot water storage amount set in advance is used outside the above-mentioned midnight time zone, it is set so that the heating operation is performed.

  Next, a hot water supply switching device 30 which is a main part of the present invention will be described. The hot water supply switching device 30 includes a first flow rate adjusting valve 31 provided at the end of the outlet pipe 16, a second flow rate adjusting valve 32 provided at the end of the outlet pipe 26, a mixing valve 33 as hot water mixing means, and these The hot water supply switching control device 35 controls the valve of the hot water, and hot water discharged from the first hot water storage tank 11 and hot water discharged from the second hot water storage tank 21 based on the hot water temperature T2 in the first hot water storage tank 11. The hot water is discharged from at least one of the hot water, and the temperature is adjusted so that the hot water temperature discharged from the hot water tap becomes a set temperature that is a required hot water temperature desired by the user. The first flow rate control valve 31 is a valve that opens and closes and discharges hot water from the hot water in the first hot water storage tank 11, and the second flow rate control valve 32 opens and closes and flows out hot water from the hot water in the second hot water storage tank 21. It is a valve to adjust.

  The mixing valve 33 is a three-way valve, one of which is connected to the water supply pipe 13 into which tap water flows and the other is connected to the downstream side of the first flow rate adjustment valve 31 and the second flow rate adjustment valve 32. The opening area ratio is adjusted based on temperature information of the feed water temperature T1 detected by the water temperature sensor 13a and the hot water temperature (the hot water temperature T2 in the first hot water storage tank 11 and the hot water temperature in the second hot water storage tank 11). By adjusting the mixing ratio between the hot water supplied from the outlet pipes 16 and 26 and the tap water introduced from the water supply pipe 13, the temperature is set to a set temperature which is a required hot water supply temperature desired by the user. The temperature is adjusted.

  On the downstream side of the mixing valve 33, a hot water tap (not shown) is provided at the end, and a hot water thermistor (not shown) for detecting the hot water temperature is provided in the middle of the mixing valve 33. The temperature adjustment of the mixing valve 33 is fed back so as to be output to the water switching control device 35. Further, in the present embodiment, the hot water supply location has been described as one location, but the present invention is not limited to this, and a plurality of hot water taps and mixing valves 33 are installed downstream of the first flow rate adjustment valve 31 and the second flow rate adjustment valve 32. May be.

  The hot water supply switching control device 35 is a microcomputer that controls the first flow rate adjustment valve 31, the second flow rate adjustment valve 32, and the mixing valve 33, and is electrically connected to the heat collection control device 15 and the heat source control device 25. Has been. Furthermore, temperature information from the feed water temperature sensor 13a and tapping temperature sensors 11e and 21e and an operation signal from an operation panel (not shown) are input. The hot water supply switching control device 35 is provided with a hot water supply switching control program for controlling the first flow rate adjustment valve 31 and the second flow rate adjustment valve 32.

  Next, the operation of the hot water storage type hot water supply apparatus having the above configuration will be described. First, when a power switch (not shown) is turned on, the heat source control device 25 controls the heat pump unit 22 to perform normal temperature control hot water supply control. In this temperature control hot water supply control, when the midnight time zone is reached, the heat pump unit 22 is operated based on temperature information from each thermistor (not shown) and temperature sensor to heat the tap water in the second hot water storage tank 11. And store hot water (for example, 85 ° C. hot water). Therefore, after the end of the midnight time zone (for example, 7:00 am), the amount of hot water stored according to the amount of hot water used for one day is stored in the second hot water storage tank 21.

  On the other hand, when a power switch (not shown) is turned on, the solar water heater 10 is operated by a heat collecting control device 15 so that a water temperature sensor (not shown) provided in the solar heat collector 12 has a predetermined temperature on a sunny day, for example. When the above is reached, the circulation pump 17a is operated to circulate the tap water in the first tank 11 to the solar heat collector 12, and the hot water heated by the solar heat collector 12 is stored in the first tank 11. It is done. Thereby, the hot water temperature T2 in the first tank 11 is warmed by solar heat. When the weather temperature is cloudy or rainy, if the water temperature sensor (not shown) is below a predetermined temperature, the circulation pump 17a is stopped and the tap water in the first tank 11 is not circulated to the solar heat collector 12. The hot water temperature T2 does not rise.

  When one of the hot water taps (not shown) is opened, the hot water switching control device 35 in the hot water switching device 30 is based on the hot water temperature T2 stored in the first hot water storage tank 11. Thus, the hot water supplied from the first hot water storage tank 11 and the hot water supplied from the second hot water storage tank 21 are controlled to discharge at least one hot water. Specifically, it is controlled based on a hot water supply switching control program shown in FIG.

  Explaining this control program, as shown in FIG. 2, it is determined in step 351 whether or not the hot water temperature T2 in the first hot water storage tank 11 detected by the hot water temperature sensor 11e is higher than the hot water supply set temperature Ts. If the hot water temperature T2 is higher than the hot water supply set temperature Ts, the first flow rate adjustment valve 31 is opened in step 352. Thereby, the hot water in the first hot water storage tank 11 flows out to the mixing valve 33, and the hot water supplied from the first hot water storage tank 11 and the tap water supplied from the water supply pipe 13 are mixed by the mixing valve 33. The temperature is adjusted to the hot water supply set temperature Ts, and hot water is supplied from the hot water tap.

  In step 351, if hot water temperature T2 is lower than hot water supply set temperature Ts, it is determined in step 353 whether hot water temperature T2 is higher than water supply temperature T1, and if hot water temperature T2 is higher than water supply temperature T1. In step 354, both the first flow rate adjustment valve 31 and the second flow rate adjustment valve 32 are opened and the flow rate is adjusted. In this flow rate adjustment, the amount of hot water discharged from the first flow rate adjustment valve 31 by the second adjustment valve 32 is adjusted to be equal to or higher than the hot water supply set temperature Ts. As a result, the hot water in the first hot water storage tank 11 and the hot water in the second hot water storage tank 21 are mixed and discharged to the mixing valve 33, and the tap water supplied from the water supply pipe 13 is further supplied by the mixing valve 33. Are mixed to adjust the temperature to the hot water supply set temperature Ts, and hot water is supplied from the hot water tap. Accordingly, hot water on the first hot water storage tank 11 side can be used positively.

  If the hot water temperature T2 is lower than the feed water temperature T1 in step 353, the second flow rate adjustment valve 32 is opened in step 355. Thereby, the hot water in the 1st hot water storage tank 11 flows out into the mixing valve 33, and the hot water supplied from the second hot water storage tank 21 and the tap water supplied from the water supply pipe 13 are mixed by the mixing valve 33. The temperature is adjusted to the hot water supply set temperature Ts, and hot water is supplied from the hot water tap.

  According to the hot water storage type hot water supply apparatus of the first embodiment described above, the hot water discharged from the first hot water storage tank 11 and the second hot water storage tank 21 based on the hot water temperature T2 of the hot water stored in the first hot water storage tank 11. By having the hot water supply switching device 30 for discharging at least one of the hot water to be discharged from the hot water, the heat pump unit 22 can discharge the hot water heated by the solar heat collector 12 on a sunny day. Since the total operating time for boiling water is greatly shortened, energy saving and low maintenance costs can be achieved.

  Moreover, on hot days when the solar heat cannot be used, the hot water heated by the heat pump unit 22 comprising the heat pump cycle can be discharged, so the comfort in the hot water supply function is not impaired. Specifically, when the hot water temperature T2 stored in the first hot water storage tank 11 is higher than the necessary hot water temperature Ts, the hot water water on the first hot water storage tank 11 side is controlled to discharge hot water. The total operation time for heating the heat pump unit 22 can be shortened by preferentially discharging hot water from the hot water storage tank 11 side.

  In addition, when the hot water temperature T2 is higher than the water supply temperature T1 and lower than the required hot water supply temperature Ts, the hot water supply on the first hot water storage tank 11 side and the second hot water storage tank 21 are controlled to discharge hot water. By controlling the hot water storage tank 11 side to actively increase the flow rate, it is possible to reduce the amount of hot water discharged from the second hot water storage tank 21 side, so the total operation time for boiling the heat pump unit 22 can be shortened. .

  Furthermore, when the hot water temperature T2 is lower than the feed water temperature T1, the hot water on the second hot water storage tank 21 side is controlled so that the hot water is discharged. While it is easy to detect that the hot water supply device is stopped, the hot water boiled up by the heat pump unit 22 can be discharged, so the comfort in the hot water supply function is not impaired.

  Moreover, since the heat pump unit 22 is a heat pump cycle in which carbon dioxide is used as a refrigerant, the heat pump unit 22 using carbon dioxide is a supercritical heat pump cycle, so hot water is supplied at a high temperature (for example, about 85 to 90 ° C.). In addition, the second hot water storage tank 21 can be made smaller and more economical than a heat pump cycle using a refrigerant of known Freon or alternative Freon.

  In addition, by providing the mixing valve 33 on the downstream side of the first flow rate adjustment valve 31 and the second flow rate adjustment valve 32, the hot water temperature in the first and second hot water storage tanks 11 and 21 is equal to or higher than the hot water supply set temperature Ts. The stored hot water can be used up. Therefore, in the heat pump unit 22 that presets the amount of hot water used per day and performs the heating operation in the midnight hours when the power rate is low, the operation time for heating in the hours other than the midnight hours may be reduced. it can. As a result, energy saving and low maintenance costs can be achieved.

(Second Embodiment)
By the way, in the second hot water storage tank 21, when hot water in the second hot water storage tank 21 is discharged from the outlet pipe 26, tap water flows in from the water supply pipe 13, and as the time passes, the vicinity of the center of the second hot water storage tank 21 is reached. The temperature of the water drops (this is called medium temperature water). When it is determined that the amount of stored hot water is insufficient with respect to the expected hot water supply load at this time, the heat pump unit 22 performs the heating operation even when the heat pump unit 22 is not in the midnight time zone.

  In such a case, since the temperature of the water supply sucked into the heat pump unit 22 is higher than that of tap water, there is a problem that the efficiency of the heat pump cycle is lowered. Therefore, in the present embodiment, this medium temperature water is configured to be supplied to the first hot water storage tank 11 side. Specifically, as shown in FIG. 3, a supply pipe which is a medium-temperature water supply means is provided from the center of the second hot water storage tank 21 toward the lower part of the first hot water storage tank 11, and the first hot water storage tank 11 side is provided. The water supply pipe 13 is provided with an on-off valve 13b.

  A water temperature sensor 21f that detects the temperature of the hot water at the center is provided at the center of the second hot water storage tank 21 and is electrically connected so that temperature information of the water temperature sensor 21f is input to the heat source control device 25. Yes. The on-off valve 13b is electrically connected to the heat collection control device 15, and on-off control is performed based on the temperature information of the water temperature sensor 21f. Incidentally, the on-off valve 13b is opened when the hot water temperature in the central portion of the second hot water storage tank 21 detected by the water temperature sensor 21f falls below a predetermined temperature.

  Thus, when the hot water temperature T2 in the first hot water storage tank 21 is equal to or higher than the feed water temperature T1, the hot water in the first hot water storage tank 21 is discharged from the outlet pipe 16, and the on-off valve 13b is closed. 2 Medium temperature water is supplied from the hot water storage tank 21. Therefore, tap water can be allowed to flow into the second hot water storage tank 21 from the water supply pipe 13.

  According to the hot water storage type hot water supply apparatus having the above configuration, hot water in the second hot water storage tank 21 is supplied to the first hot water tank 11 side, so that tap water is supplied to the second hot water tank 21 side. Therefore, when the heat pump unit 22) is in a boiling operation, the operation of the heat pump cycle can be achieved by inhaling and operating the tap water having a lower temperature than the hot water supply water.

(Other embodiments)
In the above embodiment, the solar water heater 10 is configured to circulate the hot water in the first hot water storage tank 11 directly to the solar heat collector 12, but this is not limiting, and as shown in FIG. A heat exchanger 19 is disposed in one hot water storage tank 11, and an antifreeze is used as a heat medium in a circulating water circuit 17 that circulates between the heat exchanger 19 and the solar heat collector 12. It may be configured to exchange heat with tap water. This eliminates the need for draining water to prevent freezing in the circulating water circuit 17 in winter. Thereby, energy saving can be achieved.

  Moreover, in the above embodiment, although the hot water supply switching device 30 was comprised with the two flow volume adjustment valves 31 and 32, you may provide not only this but the switching valve 34 as shown in FIG. However, at this time, when the hot water temperature T2 in the first hot water storage tank 11 is higher than the hot water supply set temperature Ts, hot water is discharged from the first hot water storage tank 11 side, and when the hot water temperature T2 is lower than the hot water supply set temperature Ts. The hot water supplied from the second hot water storage tank 21 may be discharged.

  In the above embodiment, the heat pump unit 20 using carbon dioxide as a refrigerant has been described as a heat source device. However, the present invention is not limited to this, and a general heat pump cycle using a refrigerant such as chlorofluorocarbon or alternative chlorofluorocarbon may be used.

It is a schematic diagram which shows the whole structure of the hot water storage type hot water supply apparatus in 1st Embodiment of this invention. It is a flowchart which shows the control processing of the hot water switching control program of the hot water switching control apparatus 35 in 1st Embodiment of this invention. It is a schematic diagram which shows the whole structure of the hot water storage type hot water supply apparatus in 2nd Embodiment of this invention. It is a schematic diagram which shows the whole structure of the hot water storage type hot water supply apparatus in other embodiment. It is a schematic diagram which shows the whole structure of the hot water storage type hot water supply apparatus in other embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... 1st hot water storage tank 12 ... Solar heat collector 13 ... Water supply piping (water supply means)
15 ... Heat collection control device (heat collection control means)
18 ... Supply pipe (medium temperature water supply means)
21 ... Second hot water storage tank 22 ... Heat pump unit (heat source device)
30 ... Hot water supply switching device 33 ... Mixing valve (hot water mixing means)

Claims (7)

Solar collector (12),
A first hot water storage tank (11) for storing hot water heated by the solar heat collector (12), connected to a water supply means (13) for supplying tap water for hot water supply;
A second hot water storage tank (21) that is installed in parallel with the first hot water storage tank (11) and stores hot water;
A heat source device (22) which comprises a heat pump cycle and circulates hot water in the second hot water storage tank (21) to perform a boiling operation;
Based on the hot water temperature of hot water stored in the first hot water storage tank (11), connected to the hot water and hot water discharge circuits (16, 26) of the first hot water storage tank (11) and the second hot water storage tank (21). A hot water supply switching device (30) for discharging hot water from the first hot water storage tank (11) and hot water discharged from the second hot water storage tank (21). Hot water storage type hot water supply device.   When the hot water temperature of the hot water stored in the first hot water storage tank (11) is higher than the required hot water temperature, the hot water supply switching device (30) is configured to supply hot water on the first hot water storage tank (11) side. The hot water storage type hot water supply apparatus according to claim 1, wherein the hot water storage apparatus is controlled so as to discharge hot water.   In the hot water supply switching device (30), the hot water temperature of hot water stored in the first hot water storage tank (11) is higher than the water temperature of tap water supplied from the water supply means (13) and more than the required hot water temperature. 2. The hot water storage type hot water supply apparatus according to claim 1, wherein the hot water supply water on the first hot water storage tank (11) side and the second hot water storage tank (21) are discharged when the temperature is lower.   When the hot water temperature stored in the first hot water storage tank (11) is lower than the temperature of the tap water supplied from the water supply means (13), the hot water supply switching device (30) 2. The hot water storage type hot water supply apparatus according to claim 1, wherein the hot water supply water on the hot water storage tank (21) side is controlled to be discharged.   The hot water supply switching device (30) includes at least one of hot water discharged from the first hot water storage tank (11) and hot water discharged from the second hot water storage tank (21), and the water supply means ( 13. Hot water storage means according to any one of claims 1 to 4, further comprising hot water mixing means (33) for adjusting the required hot water supply temperature by mixing with tap water supplied from 13). Water heater. Medium hot water supply means (18) for supplying hot hot water in the second hot water storage tank (21) to the first hot water storage tank (11), and hot water in the first hot water storage tank (11) There is provided a heat collection control means (15) for controlling the hot water supplied to the solar heat collector (12) to be circulated and heated by the solar heat collector (12) in the first hot water storage tank (11). And
The heat collection control means (15) stops the water supply from the water supply means (13) when the hot water in the second hot water storage tank (21) reaches a predetermined medium temperature water area, and the medium temperature water The hot water storage type hot water supply device according to claim 1, wherein the hot water supply device is controlled so as to supply medium temperature water from the supply means (18).   The hot water storage type hot water supply apparatus according to any one of claims 1 to 6, wherein the heat source device (22) is a heat pump cycle in which carbon dioxide is used as a refrigerant.

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