JP2013174379A - Hot water supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hot water supply device capable of performing heat recovery operation without freezing water in piping in a lower part of a hot water storage tank and its adjacent part even when an outside air temperature is low.SOLUTION: In a hot water supply device, hot water from a hot water storage tank 1 flows to a heat recovery forward pipe 33, a three-way valve 37, a switching means 32, a heat exchanger 4, and a heat exchange return pipe 16 in order when a heat recovery operation for recovering heat which hot water of a bath tab 3 has using a heat exchanger 4, and water from a lower part of the hot water storage tank 1 flows to the heat recovery forward pipe 33, the three-way valve 37, and a hot water storage tank lower part return pipe 39 in order when the outside air temperature detected by an outside air temperature detecting means 38 is a predetermined temperature or lower and freezing prevention operation is conducted. The hot water supply device is capable of conducting heat recovery operation without freezing water in a piping in the lower part of the hot water storage tank and its adjacent part even when an outside air temperature is low.

Description

  The present invention relates to a hot water supply apparatus having a heat recovery function.

  Conventionally, this type of hot water supply apparatus includes a reheating operation for heating the hot water in the bathtub and a heat recovery operation for recovering heat from the hot water in the bathtub (for example, see Patent Document 1).

  FIG. 13 shows a hot water supply apparatus having a heat recovery operation as a function. 1 is a hot water storage tank, 2 is a heat pump unit, 3 is a bathtub, 4 is a heat exchanger, 5a is a hot water tank water transport pump, and 5b is a bath water transport pump. , 6 is a heat recovery branch pipe, 7 is a three-way valve, 8 is a high temperature water supply pipe, 9 is a low temperature water supply pipe, 10 is a hot water supply pipe, 11 is a mixing valve, 12 is a bath water circulation pipe, 13 is an on-off valve, 14 is A water supply pipe, 15 is a hot water supply branch pipe, and 16 is a heat exchange return pipe.

  The bathtub water circulation pipe 12 is configured by connecting the forward pipe and the return pipe of the bathtub 3 in an annular shape, and includes a heat exchanger 4 and a bathtub water conveyance pump 5b on the circuit.

  The mixing valve 11 is configured to connect the high temperature water supply pipe 8 and the low temperature water supply pipe 9 to the inlet side, and connect the hot water supply pipe 10 to the outlet side, and the bathtub water circulation pipe 12 via the on-off valve 13. Connected. Further, a bathtub water temperature detecting means 17 for detecting the water temperature in the bathtub is provided in the middle of the bathtub water circulation pipe 12.

  When this hot water supply apparatus performs bath automatic operation, first, hot water stored in the hot water storage tank 1 and water supplied from the water supply pipe 14 are mixed with hot water at a desired temperature by the mixing valve 11 to supply hot water to the bathtub 3. . After the hot water is supplied to the bathtub 3, a heat retaining operation is performed in order to keep the temperature of the hot water constant for a certain period of time.

  The heat insulation operation is performed when the bath water temperature falls below a certain temperature. The hot water storage tank water transport pump 5a and the bath water transport pump 5b are operated, and the heat exchanger 4 performs hot water (for example, The hot water (for example, about 35 ° C.) in the bathtub 3 is heated by about 80 ° C.).

  Moreover, in order to judge whether the water temperature of the bathtub 3 has fallen below the fixed temperature, the bathtub water temperature detection operation | movement which drives only the bathtub water conveyance pump 5b is performed intermittently.

  When the bath water temperature detecting means 17 detects that the water temperature of the bathtub 3 is lowered below a certain temperature, the heat retaining operation is performed, and when the bath water temperature detecting means 17 is not lowered, it waits as it is. After a certain period of time has elapsed, automatic bath operation is automatically terminated.

  Next, when the reheating operation is performed, the hot water storage tank water transfer pump 5a and the bathtub water transfer pump 5b operate, and the hot water (for example, about 80 ° C.) in the hot water storage tank 1 is stored in the bathtub in the heat exchanger 4. The hot water in 3 (for example, about 35 ° C.) is heated. As a result, the water temperature in the bathtub 3 rises, and the amount of heat (heat storage amount) stored as hot water in the hot water tank 1 decreases.

  Finally, in the case of performing the heat recovery operation, the hot water tank water transfer pump 5a and the bath water transfer pump 5b are similarly operated. In the heat exchanger 4, the water in the hot water tank 1 (for example, about 10 ° C.) Cools the water (for example, about 35 ° C.) in the bathtub 3 and recovers heat.

JP 2009-198115 A

  However, the conventional configuration does not disclose the relationship between water freezing at low outside air temperature and heat recovery operation.

  The present invention solves the above-mentioned conventional problems, and provides a hot water supply apparatus capable of performing a heat recovery operation without freezing water in a pipe in the lower part of a hot water tank or in the vicinity thereof at a low outside air temperature. With the goal.

  In order to solve the conventional problems, a hot water supply apparatus of the present invention includes a hot water tank, a bathtub, a heat exchanger in which hot water in the hot water tank and hot water in the bathtub exchange heat, and in the hot water tank. The heat exchange pipe connected to the heat exchanger via the switching means so that the hot water at the upper part of the water flows into the heat exchanger, and the hot water exchanged with the hot water in the bathtub by the heat exchanger again. A heat exchange return pipe connected to the hot water tank so as to return to the hot water tank, and the hot water in the lower part of the hot water tank to the heat exchanger via the switching means so that hot water flows to the heat exchanger. A connected heat recovery pipe, a hot water tank lower return pipe connected to a substantially lower part of the hot water tank through a three-way valve from the middle of the heat recovery pipe, and an outside air temperature detecting means for detecting the outside air temperature, Control means, and heat from the hot water in the hot tub is transferred by the heat exchanger. When performing the heat recovery operation to recover, the hot water from the hot water tank flows in the order of the heat recovery forward pipe, the three-way valve, the switching means, the heat exchanger, and the heat exchange return pipe, When freezing prevention operation is performed when the outside air temperature detecting means detects a predetermined temperature or less, water from the hot water tank flows in the order of the heat recovery forward pipe, the three-way valve, and the hot water tank lower return pipe. It is characterized by that.

  Thereby, at the time of low outside air temperature, the heat recovery operation can be carried out without freezing the water in the lower part of the hot water tank or in the vicinity of the pipe.

  ADVANTAGE OF THE INVENTION According to this invention, the hot water supply apparatus which can implement heat recovery operation can be provided, without freezing the water in piping of the hot water tank lower part and its vicinity at the time of low external temperature.

Configuration diagram of hot water supply apparatus in Embodiment 1 of the present invention (a diagram showing the flow direction of water and hot water during boiling operation) Block diagram of the heat recovery operation control means Conceptual diagram of control method for automatic bath operation and heat recovery operation Conceptual diagram of the control method for the chasing operation and heat recovery operation Circuit configuration diagram showing the flow of water and hot water when hot water is supplied to the bathtub during automatic bath operation Circuit configuration diagram showing the flow direction of water and hot water during warm-up operation and chasing operation during automatic bath operation Circuit configuration diagram showing the flow direction of water and hot water during bath water temperature detection operation during automatic bath operation Circuit configuration diagram showing the flow direction of water and hot water during the heat recovery operation The figure which showed the change of the temperature distribution in the hot water tank by the heat recovery operation Diagram showing the efficiency of the heat pump unit Diagram showing the relationship between the heat recovery amount and heat pump unit input Flow chart of the heat recovery operation control operation Configuration diagram of conventional hot water supply equipment

  1st invention is a hot water storage tank, a bathtub, the heat exchanger in which the hot water in the said hot water tank and the hot water in the said bathtub heat-exchange, and the hot water of the substantially upper part in the said hot water tank in the said heat exchanger. A heat transfer pipe connected to the heat exchanger via switching means so as to flow, and the hot water tank so that the hot water exchanged with the hot water of the bathtub by the heat exchanger returns to the hot water tank again. A heat exchanger return pipe connected to the heat exchanger via the switching means, so that hot water in the lower part of the hot water tank flows to the heat exchanger, and the heat recovery return pipe connected to the heat exchanger, A hot water tank lower return pipe connected to a substantially lower part of the hot water tank through a three-way valve from the middle of the recovery forward pipe, an outside air temperature detecting means for detecting the outside air temperature, and a control means, and by the heat exchanger When performing a heat recovery operation to recover the heat of the hot water in the bathtub to the hot water in the hot water storage tank, The hot water from the hot water tank flows in the order of the heat recovery forward pipe, the three-way valve, the switching means, the heat exchanger, and the heat exchange return pipe, and the outside air temperature detecting means detects a predetermined temperature or less. In this case, when performing the freeze prevention operation, the hot water supply apparatus is configured such that water from the hot water tank flows in the order of the heat recovery forward pipe, the three-way valve, and the hot water tank lower return pipe. .

  Thereby, at the time of low outside air temperature, the heat recovery operation can be carried out without freezing the water in the lower part of the hot water tank or in the vicinity of the pipe.

  The second invention is characterized in that when the outside air temperature detecting means detects the temperature equal to or lower than the predetermined temperature, the heat recovery operation is performed shorter than a normal operation time.

  Thereby, freezing of the hot water tank lower return pipe can be prevented during the heat recovery operation at the low outside air temperature.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a diagram showing a configuration of a hot water supply apparatus according to Embodiment 1 of the present invention.

  In FIG. 1, a hot water supply apparatus includes a hot water tank 1, a heat pump unit 2 as a heating means for heating the water in the hot water tank 1, a bathtub 3 to be subjected to heat recovery, water in the bathtub 3, and the hot water tank 1. A heat exchanger 4 configured to exchange heat with water, a water supply pipe 14 connected to the hot water tank 1, a first hot water pipe 22 connected to substantially the upper part of the hot water tank 1, and a first It is comprised from the position where the hot water pipe 22 and the water supply pipe 14 were connected, ie, the 2nd hot water pipe 23 connected to the trunk | drum approximate center part of the hot water storage tank 1 in the height direction.

  The hot water supply device is connected to the high temperature water mixing valve 24 in which the first hot water discharge pipe 22 and the second hot water discharge pipe 23 are connected to the inlet side, and to the outlet side of the high temperature water mixing valve 24. A high-temperature water supply pipe 8 for supplying high-temperature water therein, a low-temperature water supply pipe 9 branched from the water supply pipe 14 and supplying low-temperature water in the hot water tank 1 or from the water supply pipe 14, and these high-temperature water supply pipes 8 The mixing valve 11 is connected to the low temperature water supply pipe 9 on the inlet side, the hot water supply pipe 10 is connected to the outlet side of the mixing valve 11, and the on-off valve 13 is connected in the middle of the hot water supply pipe 10. Yes.

Further, the hot water pipe 33 connected to the heat exchanger 4 through the switching means 32 so that the hot water in the upper part of the hot water tank 1 flows to the heat exchanger 4, and the heat exchanger 4 has a bathtub. The hot water of the hot water tank 1 exchanged with the hot water of No. 3 is returned to the hot water tank 1 again, at a position between the first hot water discharge pipe 22 and the second hot water discharge pipe 23 in the height direction of the hot water storage tank 1, It is comprised from the heat exchanger return pipe 16 connected to the approximate center part of the hot water tank 1.

  Further, during a boiling operation in which hot water in the hot water tank 1 is heated and stored in the hot water tank 1 again, the hot water heated to a predetermined temperature by the heat pump unit 2 as the heating means, as shown in FIG. However, the heat recovery forward pipe 35 connected to the substantially lower part of the hot water tank 1 is connected to the switching means 32 via the heat pump unit 2 and the three-way valve 37 in this order so that it returns to the substantially upper part of the hot water tank 1. The switching means 32 is connected to a boiling return pipe 36 connected to substantially the upper part of the hot water tank 1, and transports hot water in the hot water tank 1 by the boiling pump 5c.

  Further, the heat pump unit 2 is provided with an outside air temperature detecting means 38. When the outside air temperature detecting means 38 detects a predetermined temperature or less when the heating operation is stopped, the hot water at the lower part of the hot water tank 1 is again stored in the hot water tank. The three-way valve 37 is switched so as to return to the lower part of 1, and the heat recovery forward pipe 35, the heat pump unit 2, the three-way valve 37, and the hot water tank lower return pipe 39 are pumped to raise water stored in the lower part of the hot water tank 1 In 5c, the freeze prevention operation is performed by circulating the water by returning it to the lower part of the hot water tank 1 again.

  Further, during the heat recovery operation, as shown in FIG. 8, the heat recovery outlet pipe 35 connected to the substantially lower part of the hot water tank 1 so that the hot water in the lower part of the hot water tank 1 flows to the heat exchanger 4. Is connected to the switching means 32 that switches the flow path with respect to the boiling operation time through the heat pump unit 2 and the three-way valve 37 that are the heating means in order, and the switching means 32 is connected to the heat return pipe. 16 is connected.

  Furthermore, the hot water supply device includes a hot water tank water transfer pump 5a as a first transfer pump that circulates water in the first flow path of the hot water tank 1 and the heat exchanger 4, and a second flow of the heat exchanger 4. Bathtub water conveyance as a second conveyance pump for circulating water in the second flow path of the bathtub 3 and the heat exchanger 4 and the bathtub water circulation pipe 12 connected so that the water of the bathtub 3 circulates in the road And a pump 5b.

  Here, the heat exchange return pipe 16 is connected to the hot water tank 1 at a position between the first hot water pipe 22 and the second hot water pipe 23 in the vertical direction of the hot water tank 1. When hot water is supplied to the bathtub 3, the bathtub water circulation pipe 12 is used.

  The remote controller 25 installed in the bathroom, in the bathroom, or in the kitchen is provided with a heat recovery operation start switch 26 for the user to arbitrarily start the heat recovery operation. The water level sensor 27 for detecting the water level of the hot water in the bathtub 3 by measuring the water pressure and the bath water temperature detecting means 17 for detecting the water temperature of the bathtub 3 are provided. A plurality of hot water storage temperature detecting means 28a to 28e are provided for detecting the water temperature inside.

  Moreover, the bathtub water circulation piping 12 is provided with the bathtub water detection means 31, and when the bathtub water is circulated, the presence or absence of the bathtub water can be detected. The bathtub water detection means 31 can also be used as a flow switch or a flow sensor.

  Furthermore, based on the outputs of the plurality of hot water storage temperature detection means 28a to 28e, the water level sensor 27, the bath water temperature detection means 17 and the operation of the heat recovery operation start switch 26, the hot water supply to the bathtub 3 and the time set in advance thereafter Only bath automatic operation control means 29 as hot water supply control means for controlling automatic bath operation for maintaining the temperature of the bathtub water and maintaining the amount of water, and reheating operation control means 30 for controlling the reheating operation for heating the water in the bathtub 3. The hot water storage tank 1 is provided with operation control means 18 including heat recovery operation control means 21 for controlling the heat recovery operation for recovering the heat of the water in the bathtub 3.

FIG. 2 shows a block diagram of the heat recovery operation control means 21. When the heat recovery operation control means 21 is activated from the output of the water level sensor 27 and the operation state of the bath automatic operation control means 29 or the heat recovery operation start switch 26, A heat recovery operation start determination unit 50 that determines the start of the heat recovery operation, a heat recovery time maximum timer (not shown) that efficiently performs heat recovery, and a boiling operation control that controls the boiling operation by the heat pump unit 2. A required hot water storage amount acquisition unit 51 for acquiring a hot water storage amount necessary for hot water use after hot water storage from means (not shown), a hot water storage temperature distribution measurement unit 52 for measuring a hot water storage temperature distribution by the hot water temperature detection means 28a to 28e, A required boiling heat quantity calculation unit 53 that calculates a required boiling heat quantity based on the results obtained by the required hot water storage quantity acquisition unit 51 and the hot water temperature distribution measurement part 52, and hot water storage temperature distribution It consists current temperature distribution and necessary heating-up time of the heating-up completion to estimate the temperature distribution during the heating-up completion from the heat calculation unit 53 hot water storage temperature distribution estimating unit 55. by tough 52.

  Further, the boiling required for estimating the input to the heat pump unit 2 from the current temperature distribution by the hot water storage temperature distribution measuring unit 52 to the estimated temperature distribution at the completion of boiling by the hot water storage temperature distribution estimating unit 54 at the completion of boiling. The input estimation part 55 and the pump control part 56 which controls the hot water tank water conveyance pump 5a and the bathtub water conveyance pump 5b based on the time change of the input estimated value by this boiling required input estimation part 55 are comprised.

  About the hot water supply apparatus comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  As a basic operation in the use of hot water in a general home, hot water for the day is stored in the hot water tank 1 in the morning, and is sequentially used for hot water supply during an active time. When the amount of hot water storage is insufficient during use of hot water, the heat pump unit 2 may be operated as necessary, and an additional hot water storage operation may be performed.

  In recent years, there have been an increasing number of hot water supply apparatuses having a function of automatic bath operation that automatically performs from hot water supply to the bathtub 3 to heat insulation. When the bath automatic operation control means 29 performs hot water supply to the bathtub 3 and heat insulation operation, the hot water stored in the hot water storage tank 1 is used to supply hot water to the bathtub 3, and when the bath water temperature decreases, the hot water storage tank A heat insulation operation is performed using the heat of hot water stored in 1, and the bath water temperature is maintained at a preset temperature. In addition, when the reheating operation is performed by the reheating operation control means 30 and the hot water in the bathtub 3 is heated, the heat of the hot water stored in the hot water tank 1 is used.

  Most of the hot water in the hot water storage tank 1 is replaced with hot water at the time when heat use such as hot water supply for one day is completed, and a heating operation for storing hot water for the next use is performed again at midnight thereafter. At this time, the hot water supplied to the bathtub 3 for bathing is often left at a relatively high temperature with respect to the water temperature in the hot water tank 1 at the end of use of the hot water supply. A heat recovery operation is performed before or during the midnight boiling operation by the heat pump unit 2 to recover heat in the hot water tank 1.

  Next, a control method for bath automatic operation, chasing operation, and heat recovery operation will be described. The bath automatic operation control means 29 automatically supplies a predetermined amount of hot water to the bathtub 3 at a predetermined temperature, and then intermittently performs a heat retaining operation so as to maintain the bath water temperature at a preset temperature for a preset time. Perform (automatic bath operation).

  During bath automatic operation, in order to determine whether or not it is necessary to perform a heat retaining operation, a bath water temperature detecting operation is periodically performed to detect the bath water temperature. The bath water temperature is detected by the bath water temperature detection means 17, and as a result, when the bath water temperature is lower than a preset temperature by a predetermined temperature or more (for example, 1K or more), a heat insulation operation is performed to maintain the bath water temperature. If it is less than 1, do not keep warm.

At this time, the relationship between the automatic bath operation and the heat recovery operation is the same. When the heat recovery operation control means 21 is activated by the operation of the heat recovery operation start switch 26 by the user, the heat recovery operation starts. Heat recovery operation is performed in response to instructions.

  However, automatic bath operation is prioritized, and even if a heat recovery operation start switch 26 is instructed by the user to receive a heat recovery operation start instruction, the heat recovery operation control means 21 does not perform the heat recovery operation, It is also possible to control to perform the heat recovery operation after the automatic bath operation is completed.

  Conversely, even when the bath automatic operation control means 29 receives an instruction to start the bath automatic operation during the heat recovery operation, the heat recovery operation control means 21 gives priority to the bath automatic operation operation by the user and the heat recovery operation control means 21 performs the heat recovery operation. The bath automatic operation control means 29 starts the bath automatic operation (conceptual diagram is shown in FIG. 3).

  The reheating operation control means 30 circulates and warms the hot water in the bathtub 3 and ends when the bath water temperature detected by the bath water temperature detection means 17 reaches a predetermined temperature or when a predetermined time elapses from the start of the operation (refreshing). operation).

  While the reheating operation control means 30 is performing the reheating operation, the relationship between the reheating operation and the heat recovery operation is given priority to the operation by the user, and the heat recovery operation start switch 26 is operated by the user. When the recovery operation control means 21 is activated, control is performed so that the heat recovery operation is performed in response to an instruction to start the heat recovery operation even during chasing.

  However, during the reheating operation, the renewal operation is given priority, and the heat recovery operation control means 21 does not perform the heat recovery operation, and performs control so that the heat recovery operation is performed after the reheating operation is completed. It is also possible.

  Conversely, even when the reheating operation control means 30 receives an instruction for reheating operation during the heat recovery operation, the recuperation operation is given priority, and the heat recovery operation control means 21 stops the heat recovery operation and retreats. The operation control means 30 starts a chasing operation (a conceptual diagram is shown in FIG. 4).

  The operation of the valve and the pump when performing each operation and the flow of water and hot water associated therewith will be described with reference to FIGS. In the figure, the flow path is indicated by a bold line.

  First, the operation when the bath automatic operation control means 29 performs bath automatic operation will be described. FIG. 5 shows the flow of water and hot water in the circuit when hot water is first supplied to the bathtub 3. From the hot water storage tank 1, hot water from the first hot water discharge pipe 22 and the second hot water discharge pipe 23 is mixed by the high temperature water mixing valve 24 and supplied to the high temperature water supply pipe 8.

  The hot water supplied to the high-temperature water supply pipe 8 and the water supplied from the water supply pipe 14 to the low-temperature water supply pipe 9 are mixed with hot water having a desired hot water supply temperature by the mixing valve 11 and supplied to the hot water supply pipe 10. The Here, the temperature of the hot water supplied from the high-temperature water mixing valve 24 to the high-temperature water supply pipe 8 is a temperature higher than the above-mentioned desired hot water supply temperature by a predetermined temperature or more (for example, 45 ° C. or more when the desired hot water supply temperature is 40 ° C.). It is adjusted to.

  The on-off valve 13 is opened, and hot water having a desired temperature supplied to the hot water supply pipe 10 is supplied to the bathtub 3 from the bathtub water circulation pipe 12. The opening degree of the high temperature water mixing valve 24 and the mixing valve 11 is generally feedback controlled based on the temperature of hot water supplied to the high temperature water supply pipe 8 and the hot water supply pipe 10 respectively connected to the outlet side. For the high temperature water mixing valve 24, the hot water from the first outlet pipe 22 and the second outlet pipe, and for the mixing valve 11, the hot water from the high temperature water supply pipe 8 and the temperature of the feed water from the low temperature water supply pipe 9. It depends on.

  FIG. 6 shows the flow of water and hot water in the circuit when the hot water in the bathtub 3 is kept warm. The hot water storage tank water transfer pump 5a and the bathtub water transfer pump 5b start operation, and hot water from the hot water tank 1 is heated from the first outlet pipe 22 by the operation of the hot water storage tank water transfer pump 5a. Hot water is supplied to the switching means 32 through the pipe 33 and supplied to the heat exchanger 4.

  At this time, the hot water of the bathtub 3 circulating through the bathtub water circulation pipe 12 is heated by the heat exchanger 4 to raise the bathtub water temperature. On the other hand, the hot water that has left the heat exchanger 4 and has a relatively low temperature returns to the substantially central portion of the hot water tank 1 through the heat exchange return pipe 16.

  FIG. 7 shows the flow of water and hot water in the circuit when the bathtub water temperature detection operation for detecting the water temperature in the bathtub 3 is performed. The bathtub water conveyance pump 5b starts operation, and the hot water in the bathtub 3 circulates in the bathtub water circulation pipe 12. At this time, the hot water tank water transfer pump 5a does not operate. The bathtub water temperature detection means 17 detects the bathtub water temperature and determines whether or not to perform a heat retaining operation.

  Next, the operation when the reheating operation control means 30 performs the reheating operation, the flow of water and hot water in the circuit when the reheating operation is performed, when the bath automatic operation control means 29 performs the heat retaining operation. Since this is the same as shown in FIG.

  Finally, FIG. 8 shows the flow of water and hot water in the circuit when the heat recovery operation control means 21 performs the heat recovery operation of the hot water remaining in the bathtub 3. When the bath water transfer pump 5b is operated, and then the hot water tank water transfer pump 5a is operated and the heat recovery operation is started, the heat recovery is performed so that the hot water from the substantially lower portion of the hot water tank 1 flows to the heat exchanger 4. The heat is supplied from the heat recovery forward pipe 35 connected to the heat exchanger 4 through the forward pipe 35, the heat pump unit 2 as the heating means, and the three-way valve 37 in this order.

  At this time, the hot water supplied from the substantially lower part of the hot water tank 1 is supplied to the heat exchanger 4 by the supply to the above-mentioned path. The supplied hot water performs heat exchange with the hot water in the bathtub 3 circulating through the bathtub water circulation pipe 12 in the heat exchanger 4 to recover heat. On the other hand, the hot water leaving the heat exchanger 4 and having a relatively high temperature returns to the hot water storage tank 1 through the heat exchange return pipe 16.

  In addition, the required flow volume by the bathtub water conveyance pump 5b is ensured by making the conveyance amount of the hot water by the bathtub water conveyance pump 5b larger than the conveyance amount of the hot water by the hot water tank water conveyance pump 5a, and the temperature distribution in the bathtub 3 is It is made uniform and heat can be stably recovered from the bathtub 3, and the flow rate by the hot water tank water transfer pump 5a becomes excessive, so that the hot water in the hot water tank 1 is not stirred and the temperature stratification is performed. Since it can hold | maintain, it becomes possible to perform the boiling operation of the hot water in the hot water storage tank 1 mentioned later efficiently.

  In addition, when the heat recovery operation is performed during the freeze prevention operation of the hot water tank lower return pipe 39, the maximum operation time of the heat recovery time is shorter than normal (for example, normally 60 minutes is reduced to 30 minutes), In the meantime, the hot water tank lower return pipe 39 is prevented from freezing.

  The temperature distribution in the hot water tank 1 when the heat recovery operation is performed changes in the order of 40, 41, and 42 shown in FIG. That is, the temperature of the water 43 that is heat-exchanged with the bathtub 3 and flows into the hot water tank 1 from the heat exchange return pipe 16 is often lower than the hot water temperature of the hot water tank 1, and the hot water tank is operated by the hot water tank water transfer pump 5a. It moves toward the lower side of the hot water tank 1 while being mixed with the hot water of No. 1.

Since the connection position of the second hot water discharge pipe 23 is lower than the connection position of the heat exchange return pipe 16, when hot water is generated, the intermediate temperature water 44 that has come down is discharged from the second hot water discharge pipe 23, and the first It can be used by mixing with hot water 46 from the hot water pipe. Reference numeral 45 shown in FIG. 9 indicates a temperature distribution when hot water is generated after heat recovery. Thus, since the 2nd hot water discharge pipe 23 exists below the connection position to the hot water storage tank of the heat exchange return pipe 16, the collect | recovered heat | fever can be utilized effectively.

  The occurrence of hot water supply is relatively small, and the medium-temperature water that remains without being used up is reheated and used by the heat pump unit 2, but the operating efficiency of the heat pump unit 2 is as shown in FIG. The higher the water temperature, the lower it.

  As can be seen from the temperature distribution of the hot water tank 1 shown in FIG. 9, the required heating amount by the heat pump unit 2 after the heat recovery operation decreases as the amount of recovered heat from the bathtub 3 increases. Since the water temperature before heating becomes high and the operation efficiency at the time of reheating is reduced, it is not necessarily energy saving to perform as much heat recovery as possible.

  That is, the input (heat consumption or power consumption) to the heat pump unit 2 is obtained by subtracting the recovered heat amount obtained by the heat recovery operation from the necessary heat amount before heat recovery for obtaining the required hot water storage heat amount. As shown in FIG. 11, this value may have a minimum value for the recovered heat amount.

  Therefore, in order to obtain a higher energy saving effect, it is necessary to stop the heat recovery operation from the bathtub 3 at the time when the input to the heat pump unit 2 becomes substantially minimum in the reheating operation performed after the heat recovery operation is stopped. It is.

  As a specific method for finding the time point at which the minimum value is reached, the change of the input value to the heat pump unit 2 that is predicted based on the temperature distribution of the hot water tank 1 measured at predetermined time intervals is obtained. Judgment is made when the degree of decrease in the value is small or no longer decreases, or starts to increase.

  As shown in FIG. 10, when the hot water in the hot water tank 1 is heated by the heat pump unit 2, the temperature at the site where water is transported from the hot water tank 1 to the heat pump unit 2 (in this embodiment, the hot water tank 1 The operating efficiency of the heat pump unit 2 increases as the temperature of the lower part of the heat pump unit 2 decreases. However, when the heat recovery operation from the bathtub 3 is performed, the water recovered from the bathtub 3 flows into the hot water tank 1. There is a state in which the temperature of the part that transports water from the hot water tank 1 to the heat pump unit 2 starts to rise.

  Therefore, at the time of the heat recovery operation from the bathtub 3, the temperature of the part that transports water to the heat pump unit 2 of the hot water tank 1 is measured, and the heat recovery operation operation from the bathtub 3 is performed in the vicinity where the increase in the temperature starts to increase. By stopping the operation, it is possible to achieve substantially the maximum operating efficiency of the heat pump unit 2 during the heating operation after the heat recovery operation.

  A control method of the heat recovery operation control means 21 for obtaining a high energy saving effect in consideration of the above will be described.

  FIG. 12 is a flowchart of the operation of the heat recovery operation control means 21. It is also possible to make a setting for automatically recovering heat when the user operates the heat recovery operation start switch 26 or when a predetermined time elapses after the bath automatic operation control means 29 ends. When the heat recovery operation start determination unit 50 determines the start of the heat recovery operation, the bathtub water conveyance pump 5b is driven to determine whether or not there is water (hot water) in the bathtub 3.

At this time, the presence or absence of water (hot water) in the bathtub 3 is detected by the bathtub water detection means 31 (step 1). If it is determined that there is water (hot water) in the bathtub 3, go to step 3; If it is determined that there is no water (hot water), the heat recovery operation is terminated without starting (step 2).

  Here, in order to determine whether or not there is water (hot water) in the bathtub, first, the water level sensor 27 detects a water level proportional to the amount of hot water in the bathtub (step 1), and if it is below the preset water level. For example, the heat recovery operation can be terminated without starting (step 2).

  When the bathtub water detection means 31 determines in step 1 that there is water (hot water) in the bathtub 3, or the water level exceeds a preset water level in step 1, and sufficient water (hot water) is contained in the bathtub 3. ), The required hot water quantity acquired by the required hot water quantity acquisition unit 51, the current temperature distribution of the hot water tank 1 measured by the hot water temperature detection means 28a to 28e, and the boiling temperature of the heat pump unit 2 The temperature distribution in the hot water storage tank 1 at the time of completion of the hot water storage operation is predicted from the operating conditions such as the above, and compared with the current temperature distribution, the remaining heating amount Qr when the heat pump unit 2 heats from that point is obtained. (Step 3).

  Next, the average water temperature before boiling in the heat pump unit 2 is estimated from the measured current temperature distribution until the predicted temperature distribution at the time of completion of the hot water storage operation is reached (step 4).

  Further, the average efficiency during hot water storage operation is obtained from the average water temperature obtained in step 4 and the characteristics of the heat pump unit 2 shown in FIG. 10, and the remaining heating amount Qr obtained in step 3 is divided by this average efficiency to obtain hot water storage water. The input Qin during operation is estimated (step 5).

  Qin obtains a difference from Qin−f which is a value obtained at the previous evaluation time, and when it is smaller than a predetermined deviation q, that is, when a change in estimated input gradually becomes smaller and it is determined to be a minimum value (step) 6) In Step 2, the hot water tank water transfer pump 5a and the bathtub water transfer pump 5b are stopped to end the heat recovery operation. When the difference between Qin and Qin−f is equal to or greater than q, the heat recovery operation is continued, and when the next evaluation time comes (step 8), the above operation is repeated.

  As a supplement, step 7 is executed without performing the comparison in step 6 at the first operation after the start of the heat recovery operation.

  Here, although the operation of detecting the presence or absence of water (hot water) in the bathtub 3 has been described by the bathtub water detection means 31, the bathtub 3 is detected after the heat recovery operation is started in step 1 by the bathtub water detection means 31. Even when it is determined that there is no water (hot water) inside, the heat recovery operation is stopped (step 2).

  Moreover, although the operation | movement by a water level was demonstrated to the detection of the water in the bathtub 3 at the time of the start of heat recovery driving | operation, also when a water level becomes below the preset water level after heat recovery driving | operation starts similarly, The heat recovery operation is stopped (step 2). Thereby, when the water (hot water) in the bathtub 3 runs out on the way, the heat recovery operation can be stopped.

  Although the above is the explanation of the operation, the stop of the heat recovery operation regardless of the amount of hot water in the bathtub 3 is performed because the determination of the minimum value of the input of the heat pump unit 2 is reduced. In addition to this method, when the input difference q between the evaluation times is 0, or when the sign of q is reversed from the previous evaluation time, that is, when the estimated input starts to increase, the heat recovery operation is set to the minimum value. May be stopped.

In addition, the estimated input often increases or decreases while reaching the minimum value due to a measurement error of the temperature value of the hot water tank 1 to be measured. Therefore, by storing the estimated input at the latest several evaluation times, and determining whether the minimum value has been reached by using the moving average value, the determination accuracy of whether the minimum value has been reached is further improved. Can be increased.

  Furthermore, as described above, the method of evaluating the temperature distribution each time and obtaining the input is highly accurate, but the calculation is complicated and the load on the heat recovery operation control means 21 is large.

  In that case, when a change in hot water storage temperature at a position that most affects the input is grasped in advance, and one of the hot water storage temperature detection means 28a to 28e corresponding to that position starts to rise. When the predetermined temperature rise is observed or, for example, while the detection temperature of the hot water storage temperature detection means 28d is increased and the detection temperature of the hot water storage temperature detection means 28e is not increased, the heat recovery operation is continued. The stop may be determined according to a combination of two or more temperatures.

  Specifically, it is possible to reduce the efficiency of the heat pump unit 2 by reducing the heat recovery operation by detecting that the temperature relatively close to the lower portion of the hot water tank 1 is rising. Can be obtained. Furthermore, if the change of the temperature of the upper part of the hot water tank 1 is taken into consideration, it is possible to simultaneously evaluate the amount of recovered heat by the heat recovery operation, and the accuracy is improved.

  As described above, according to the embodiment of the present invention, there is no hot water in the bathtub 3, or the heat recovery operation is not performed in a state where the amount is small, and the heat recovery operation itself cannot be performed or the effect is not obtained. Driving in can be prevented.

  At this time, if there is no or little hot water at the timing of starting the heat recovery operation, the heat recovery operation is not started, and even if the hot water decreases during the heat recovery operation and becomes such a state immediately. Stop heat recovery operation. Furthermore, if the amount of hot water is recovered, the heat recovery operation can be started or restarted, whereby an operation that does not impair the energy saving performance can be performed.

  The resumption of the heat recovery operation is automatically performed when a predetermined time elapses after the amount of hot water has recovered, but the user confirms the amount of hot water in the bathtub 3 and operates the heat recovery operation start switch 26. Since it can be restarted immediately, useless heat radiation from the bathtub 3 over time is suppressed, and energy saving is improved.

  Further, in the configuration of the piping system for realizing the automatic bath operation, the reheating operation, and the heat recovery operation, the heat recovery for recovering the heat of the hot water in the bathtub 3 to the hot water in the hot water tank 1 by the heat exchanger 4. When the operation is performed, the hot water from the hot water tank 1 flows in the order of the heat recovery forward pipe 35, the heat pump unit 2 as the heating means, the switching means 32, the heat exchanger 4, and the heat exchange return pipe 16. With this configuration, a part of the piping used at the time of heat recovery can be configured to be used also during the boiling operation of the hot water in the hot water storage tank described above, and a hot water supply device that realizes cost reduction can be provided. .

  In addition, it is not necessary to secure an installation space for a new member in the housing, and there is no increase in weight, material, and standby power, contributing to resource and energy savings. In addition, the heat exchanger 4 is a plate type with high heat exchange efficiency, and is installed near the connection position of the heat exchange return pipe 16 of the hot water tank 1 to make the heat exchanger 4 itself compact. As a minimum pipe length, it will save resources as well.

  When the heat recovery operation is performed, the heat recovery operation is stopped when the input to the heat pump unit 2 for boiling up the required hot water storage amount is minimized, so that the efficiency of the entire system, which is the original purpose, is reduced. Improvement can be realized and energy saving can be improved.

As a configuration, the water in the lower part of the hot water tank 1 is taken out and heated by the heat exchanger 4 and returned to the relatively upper part of the hot water tank 1. It depends on the difference in the return position.

  Furthermore, the heat recovery speed and the like can be controlled by controlling the capacity of the hot water tank water transfer pump 5a, and the operation efficiency changes depending on the difference in configuration and control.

  Therefore, in this embodiment, an optimized design is made such that an appropriate take-out position and return position can be set in consideration of usage, the capacity of the hot water tank 1, and the capacity control of the hot water tank water transfer pump 5a can be performed. Since the degree of freedom is high, it can be easily applied to a plurality of different models, and as a result, a large energy saving effect can be obtained by providing it to many users.

  Furthermore, in hot water supply from the hot water tank 1, hot water from the first hot water discharge pipe 22 and the second hot water discharge pipe 23 is appropriately mixed by the high temperature water mixing valve 24 to effectively use the medium temperature water in the hot water storage tank 1. In addition, by making the connection position of the heat exchange return pipe 16 to the hot water storage tank 1 higher than the second hot water discharge pipe 23, the hot water in the upper part of the hot water tank and the lower temperature in the lower part are inevitable in the temperature stratified hot water tank. As a result of the effective use of the medium-temperature water that can be formed between the water and the water, the amount of heat recovered from the bath water can be increased because a large amount of low-temperature water can be secured below the hot water tank even with the same heat storage amount.

  In addition, the flow of the intermediate warm water generated by the heat recovery into the relatively upper portion of the hot water storage tank 1 means that the intermediate warm water that moves below the hot water storage tank 1 while increasing is lower than the inflow position of the hot recovered hot water. Since it can be used for hot water supply through the two hot water outlet pipes 23, the amount of stored hot water can be used to the maximum extent possible.

  At the same time, the medium temperature water in the hot water tank 1 that reduces the heating efficiency of the heat pump unit 2 is reduced, so that the efficiency of the entire system can be prevented from being lowered. To do.

  Further, when the heat recovery operation is started when there is no or little bath water, the second hot water discharge pipe 23 and the heat exchange return pipe 16 are installed at appropriate positions, so that the hot water can be used well and the lower part of the hot water tank 1 In spite of the configuration of securing a large amount of low-temperature water, the hot water storage tank 5 is operated to increase the amount of hot water in the hot water storage tank.

  In this case, the effect of heat recovery cannot be obtained, and the efficiency is lowered when the heat pump unit 2 is heated. However, since the amount of hot water in the bath is detected in advance to determine the execution of the heat recovery operation, The high energy-saving property obtained by optimizing the connection position of the hot water return pipe 23 and the heat exchange return pipe 16 is not impaired.

  That is, it is possible to provide a hot water supply apparatus that appropriately controls the heat recovery operation and realizes high energy saving performance.

  As described above, the hot water supply apparatus according to the present invention can perform the heat recovery operation without freezing the water in the lower part of the hot water tank or in the vicinity of the hot water tank at a low outside air temperature. It can also be applied to large-scale uses such as business use.

DESCRIPTION OF SYMBOLS 1 Hot water tank 2 Heat pump unit 3 Bathtub 4 Heat exchanger 5a Hot water tank water conveyance pump 5b Bath water conveyance pump 5c Boiling pump 8 High temperature water supply pipe 9 Low temperature water supply pipe 10 Hot water supply pipe 11 Mixing valve 12 Bath water circulation pipe 13 Opening and closing valve DESCRIPTION OF SYMBOLS 14 Water supply pipe 16 Heat exchange return pipe 17 Bathtub water temperature detection means 18 Operation control means 21 Heat recovery operation control means 22 1st tapping pipe 23 2nd tapping pipe 24 High temperature water mixing valve 25 Remote control 26 Heat recovery operation start switch 27 Water level Sensor 28 Hot water storage temperature detection means 29 Bath automatic operation control means 30 Reheating operation control means 31 Bath water detection means 32 Switching means 33 Heat exchange pipe 35 Heat recovery forward pipe 36 Boil-up return pipe 37 Three-way valve 38 Outside air temperature detection means 39 Hot water tank lower return pipe

Claims (2)

A hot water storage tank, a bathtub, a heat exchanger for exchanging heat between the hot water in the hot water tank and the hot water in the bathtub, and a switching means so that the hot water in the upper part of the hot water tank flows to the heat exchanger. A heat exchange pipe connected to the heat exchanger, and a heat exchange connected to the hot water storage tank so that the hot water exchanged with the hot water of the bathtub is returned to the hot water storage tank again by the heat exchanger. From the middle of the return pipe, the heat recovery forward pipe connected to the heat exchanger via the switching means, so that the hot water at the lower part of the hot water tank flows to the heat exchanger, and the heat recovery forward pipe A hot water tank lower return pipe connected to a substantially lower part of the hot water tank through a three-way valve, an outside air temperature detecting means for detecting the outside air temperature, and a control means, and the hot water of the bathtub is provided by the heat exchanger. When performing a heat recovery operation for recovering heat to the hot water in the hot water storage tank, The three-way valve, the switching means, the heat exchanger, and the heat exchange return pipe so that hot water flows from the hot water storage tank in this order, and when the outside air temperature detecting means detects a predetermined temperature or lower, it freezes. When performing preventive operation, the hot water supply apparatus is configured such that water from the hot water tank flows in the order of the heat recovery forward pipe, the three-way valve, and the hot water tank lower return pipe. 2. The hot water supply apparatus according to claim 1, wherein when the outside air temperature detection unit detects the temperature equal to or lower than the predetermined temperature, the heat recovery operation is performed shorter than a normal operation time.