JP4222993B2 - Water heater - Google Patents

Description

  The present invention relates to a hot water supply apparatus that stores hot water boiled by a heat pump unit in a hot water storage tank.

  Conventionally, in a hot water supply apparatus, a hot water supply apparatus using a heat pump unit having a refrigerant circuit provided with a compressor, a heat exchanger, an evaporator as a heat collector, etc., is used to boil hot water stored in a hot water storage tank. is there.

  During boiling operation, the heat pump unit is operated in a normal cycle in which the refrigerant circulates in the order of the compressor, heat exchanger, and evaporator, and water is taken out from the lower part of the hot water storage tank, passed through the heat exchanger of the heat pump unit, and the upper part of the hot water storage tank. The hot water boiled by the heat exchanger is stored from the upper part of the hot water storage tank by utilizing the difference in specific gravity between the hot water and the water. Moreover, when hot water is supplied, hot water is taken out from the upper part of the hot water storage tank to supply hot water.

  By the way, when the outside air temperature is low, the evaporator is frosted during the operation of the heat pump unit, and the heat collection efficiency is lowered. Therefore, when the evaporator is frosted, the defrosting operation is performed to remove the frost attached to the evaporator.

  During the defrosting operation, the heat pump unit is operated in a reverse cycle in which the refrigerant circulates in the order of the compressor, evaporator, and heat exchanger, and the hot water stored in the upper part of the hot water storage tank is removed from the upper part of the hot water storage tank. By circulating through the heat exchanger so as to be taken into the lower part of the hot water storage tank, the heat exchanger collects the heat of the hot water on the refrigerant circuit side and melts and removes the frost adhering to the evaporator (for example, patent document) 1).

In addition to operating the heat pump unit in a reverse cycle at the time of defrosting, there is also a method that reliably removes frost in a short time by flowing hot water stored in a hot water storage tank over the surface of the evaporator. However, since the hot water stored in the hot water storage tank flows outside, there is a problem that the amount of hot water in the hot water storage tank decreases.
JP-A-5-272812 (page 3, FIG. 1)

  However, during the defrosting operation, the hot water stored in the upper part of the hot water storage tank is taken out and collected by the heat exchanger of the heat pump unit and then taken into the lower part of the hot water storage tank. There is.

  In addition, since hot water stored in the upper part of the hot water storage tank is used, even if it passes through the heat exchanger of the heat pump unit, the temperature remains high and the water temperature in the lower part of the hot water storage tank becomes higher. There is a problem that the boiling efficiency (COP) of the heat pump unit is lowered in order to boil the water whose water temperature is high at the time of boiling after defrosting by the heat pump unit.

  The present invention has been made in view of such points, can be defrosted without using hot water stored in the upper part of the hot water storage tank, and prevents the water temperature in the lower part of the hot water storage tank from rising, It aims at providing the hot-water supply apparatus which can prevent that the boiling efficiency of a heat pump unit falls at the time of boiling after defrosting.

The hot water supply apparatus according to claim 1 is provided with a hot water storage tank provided with an outlet at a lower part and provided with an upper inlet and a lower inlet at least at an upper part and a lower part, and a compressor, a heat exchanger and an evaporator. A heat pump unit having a refrigerant circuit and provided with a four-way valve for switching the cycle to the refrigerant circuit, and water taken out from a lower outlet of the hot water storage tank through the heat exchanger of the heat pump unit, any one of the inlets The circulation means for circulating so as to switch to one, the frost detection means for detecting the frost formation of the evaporator of the heat pump unit, and at the time of boiling, the heat pump unit is operated in a normal cycle, and the circulation by the circulation means Remove water from the bottom of the hot water storage tank and boil the hot water through the heat exchanger at the upper intake of the hot water storage tank At the time of frost detection by the boiling control means to be taken in and the frost detection means, the heat pump unit is operated by switching to a reverse cycle, water is taken out from the lower part of the hot water storage tank by circulation by the circulation means, and a heat exchanger is installed. And a defrosting control means that is introduced into the lower intake of the hot water storage tank, and a water temperature detection means that detects the water temperature of the lower part of the hot water storage tank, and the boiling control means is the water temperature detection means at the time of boiling. When the water temperature to be detected is lower than a predetermined temperature, hot water boiled through the heat exchanger by circulation by the circulation means is introduced into the lower intake of the hot water storage tank, and the water temperature detected by the water temperature detection means is a predetermined temperature. At this time, hot water boiled through the heat exchanger by circulation by the circulation means is taken into the upper intake port of the hot water storage tank .

Then, when defrosting is detected by frost detection, the heat pump unit is operated by switching to the reverse cycle, and water is taken out from the lower part of the hot water storage tank by circulation by the circulation means and taken into the lower intake of the hot water storage tank through the heat exchanger. The hot water stored in the upper part of the hot water storage tank is not used, the water in the lower part of the hot water storage tank is used for defrosting, and the water whose temperature has decreased through the heat exchanger is taken into the lower part of the hot water storage tank. Thus, the water temperature in the lower part of the hot water storage tank is prevented from rising, and the boiling efficiency of the heat pump unit is prevented from lowering during boiling after defrosting. Furthermore, when the water temperature in the lower part of the hot water storage tank is lower than the predetermined temperature at the time of boiling, the hot water boiled through the heat exchanger by circulation by the circulation means is taken into the lower intake of the hot water storage tank to reach the predetermined temperature. Thus, at the time of defrosting, the water whose temperature has been lowered through the heat exchanger is prevented from freezing in the circulation path of the circulation means.

Water heater of claim 2, wherein the hot water apparatus according to claim 1 Symbol placement, circulation means, circulation path to the inlet each via a heat exchanger from outlet of the hot water storage tank, a heat exchanger of the circulation path Intake switching means for switching and taking in the hot water passed through any one of the intakes, a circulation pump provided in the circulation path for circulating hot water, and the circulation path through a heat exchanger of this circulation path A temperature detection means for detecting the temperature of the hot water is provided, and the defrost control means controls the circulation flow rate by the circulation pump so that the water temperature detected by the temperature detection means becomes a predetermined circulation temperature.

  And at the time of defrosting, the temperature of the water passing through the heat exchanger of the circulation path is detected, and the temperature is lowered via the heat exchanger by controlling the circulation flow rate by the circulation pump so that the water temperature becomes a predetermined circulation temperature. The collected water is prevented from freezing in the circulation path, and the heat exchanger reliably collects heat from the water.

According to the hot water supply apparatus of the first aspect, when defrosting is detected by frost detection, the heat pump unit is operated by switching to the reverse cycle, water is taken out from the lower part of the hot water storage tank by circulation by the circulation means, and the hot water storage is performed through the heat exchanger. By introducing it into the lower intake of the tank, the hot water stored in the upper part of the hot water storage tank can be used to defrost using the water in the lower part of the hot water storage tank, and the temperature has decreased through the heat exchanger. By taking water into the lower part of the hot water storage tank, it is possible to prevent the water temperature in the lower part of the hot water storage tank from rising, and to prevent the boiling efficiency of the heat pump unit from being lowered during boiling after defrosting. Furthermore, when the water temperature in the lower part of the hot water storage tank is lower than the predetermined temperature at the time of boiling, the hot water boiled through the heat exchanger by circulation by the circulation means is taken into the lower intake of the hot water storage tank to reach the predetermined temperature. Thus, it is possible to prevent water whose temperature has been lowered through the heat exchanger from being frozen in the circulation path of the circulation means during defrosting.

According to the hot water supply device according to claim 2, in addition to the effect of the water heater according to claim 1 Symbol placement, during defrosting, detects the water temperature of the water passed through the heat exchanger in the circulation path, the water temperature is a predetermined cyclic By controlling the circulation flow rate by the circulation pump so as to reach the temperature, it is possible to prevent the water whose temperature has been lowered through the heat exchanger from being frozen in the circulation path, and to reliably collect heat from the water with the heat exchanger.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the hot water supply apparatus 11 includes a main body unit 12 and a heat pump unit 13 as a boiling means.

  The main unit 12 has a hot water storage tank 21 for storing hot water. The hot water storage tank 21 has a water supply port 22 at the bottom, an upper connection port 23 at the top, an intermediate connection port 24 at the middle, and a water supply port at the bottom. Lower connection ports 25 are provided above 22. During boiling hot water storage, the water supply port 22 functions as an intake port, the upper connection port 23 functions as an upper intake port, the intermediate connection port 24 functions as an intermediate intake port, and the lower connection port 25 functions as a lower intake port. . On the other hand, at the time of hot water supply, the upper connection port 23 functions as an upper outlet and the intermediate connection port 24 functions as an intermediate outlet.

  On the side of the hot water storage tank 21, hot water storage tanks are located at the height positions of 60L, 120L, 180L of hot water, for example, and from the lower side of the hot water storage tank 21, for example, at the height of 30L, 60L of hot water. Thermistors 26a to 26e for detecting the hot water temperature in 21 are arranged. The lowermost thermistor 26e is configured as water temperature detecting means for detecting the water temperature in the lower part of the hot water storage tank 21.

  A water supply pipe 29 connected to a water supply source such as a water pipe is connected to the water supply port 22 of the hot water storage tank 21 via a pressure reducing valve 30, and an upper pipe 31 is connected to the upper connection port 23 and connected to the intermediate connection port 24. Is connected to an intermediate pipe 32, and a lower pipe 33 is connected to the lower connection port 25.

  Between the hot water storage tank 21 and the heat pump unit 13, a circulation path 35 of a circulation means 34 for circulating the water in the lower part of the hot water storage tank 21 to the heat pump unit 13 is formed. This circulation path 35 is connected to the water supply port 22 of the hot water storage tank 21 so that the water in the lower part of the hot water storage tank 21 enters the heat pump unit 13, the hot water boiled by the heat pump unit 13 is discharged, and the hot water storage tank A return pipe 37 returning to 21 and a circulation pump 38 for circulating hot water through the return pipe 36 and the return pipe 37 are provided.

  Between the return pipe 37 and each of the pipes 31, 32, 33, hot water heated by the heat pump unit 13 and returned from the return pipe 37 to the hot water storage tank 21 is connected to any of the connection ports 23, 24, 25 of the hot water storage tank 21. An intake switching three-way valve 39 is provided as an intake switching means for switching to one. This inlet switching three-way valve 39 is connected to an inlet 39a to which a return pipe 37 is connected, an upper outlet 39b to which an upper pipe 31 is connected, an intermediate outlet 39c to which an intermediate pipe 32 is connected, and a lower pipe 33. The lower outlet 39d is configured such that any one of the outlets 39b to 39d is opened with respect to the inlet 39a and the rest is closed.

  The heat pump unit 13 includes a refrigerant circuit 42 filled with a refrigerant. The refrigerant circuit 42 includes a compressor 43, a heat exchanger 44 as a condenser, an expansion valve 45, and an evaporator 46 as a heat collector. A four-way valve 47 that switches between a normal cycle (forward cycle) and a reverse cycle is provided. In the normal cycle, the refrigerant circulates in the order of the compressor 43, the heat exchanger 44, the expansion valve 45, the evaporator 46, and the compressor 43, collects heat from the outside air in the evaporator 46, and circulates in the circulation path 35 in the heat exchanger 44. Boil the water to be used. The reverse cycle is switched at the time of defrosting. In this reverse cycle, the refrigerant circulates in the order of the compressor 43, the evaporator 46, the expansion valve 45, the heat exchanger 44, and the compressor 43, and the heat exchanger 44 circulates the circulation path 35. Heat is collected from the circulating water to raise the temperature of the evaporator 46 and defrost. The compressor 43, the expansion valve 45, the evaporator 46, the four-way valve 47 and the like are arranged in an outdoor unit 48 different from the main unit 12, and the heat exchanger 44 and the like are arranged in the main unit 12. Further, the evaporator 46 is provided with frost detection means 49 for detecting frost formation.

  The return pipe 36 of the circulation path 35 has a feed water temperature detection sensor 50 that detects the temperature of the feed water that reaches the heat exchanger 44, and the return pipe 37 has hot water as a temperature detection means that detects the temperature of hot water that has passed through the heat exchanger 44. A temperature sensor 51 is provided.

  The upper pipe 31 and the intermediate pipe 32 are connected to a hot water supply switching three-way valve 53 that switches hot water from the upper connection port 23 and the intermediate connection port 24 of the hot water storage tank 21 and supplies hot water. This hot water switching three-way valve 53 has an upper inlet 53a to which the upper pipe 31 is connected, an intermediate inlet 53b to which the intermediate pipe 32 is connected, and an outlet 53c to which the hot water pipe 54 is connected. On the other hand, one of the inflow ports 53a and 53b is opened and the other is closed.

  2 shows a control unit 61 that controls the hot water supply device 11. The control unit 61 includes the thermistors 26a to 26e, the feed water temperature detection sensor 50, the hot water temperature detection sensor 51, and the frost detection means 49 of the heat pump unit 13. And the like, and the compressor 43 and the four-way valve 47, the circulation pump 38, the intake switching three-way valve 39, the hot water supply switching three-way valve 53 and the like of the heat pump unit 13 are controlled.

  The controller 61 operates the heat pump unit 13 in a normal cycle at the time of boiling, takes out water from the lower part of the hot water storage tank 21 by circulation by the circulation means 34, and heats the hot water boiled through the heat exchanger 44. The function of the boiling control means 62 to be taken into the upper connection port 23 and the frost detection by the frost detection means 49 are operated by switching the heat pump unit 13 to the reverse cycle, and the circulation of the hot water storage tank 21 by the circulation by the circulation means 34. It has a function of defrosting control means for taking out water from the lower part and taking it into the lower connection port 25 of the hot water storage tank 21 through the heat exchanger 44.

  The boiling control means 62 is heated through the heat exchanger 44 by circulation by the circulation means 34 when the water temperature in the lower part of the hot water storage tank 21 detected by the thermistor 26e is lower than a preset predetermined temperature during boiling. The hot water is taken into the lower connection port 25 of the hot water storage tank 21, and when the water temperature in the lower part of the hot water storage tank 21 detected by the thermistor 26e is equal to or higher than the predetermined temperature, the water is heated by the circulation means 34 through the heat exchanger 44. The hot water is taken into the upper connection port 23 of the hot water storage tank 21. By the way, in this hot water supply device 11, since the water in the lower part of the hot water storage tank 21 is used during the defrosting operation, if the water temperature is too low, the circulation path 35 is frozen during the defrosting operation. Since the water temperature in the lower part of the hot water storage tank 21 rises and the boiling efficiency (COP) of the heat pump unit 13 decreases during the boiling operation after the defrosting operation, the predetermined value that satisfies both of these is From the experiment, the result that the temperature is preferably 10 ° C. is obtained.

  The defrost control means 63 controls the circulation flow rate by the circulation pump 38 so that the water temperature detected by the tapping temperature detection sensor 51 becomes a predetermined circulation temperature set in advance. The predetermined circulation temperature is a temperature at which water whose temperature has been lowered through the heat exchanger 44 does not freeze in the circulation path 35 and can be reliably collected from the water by the heat exchanger 44.

  Next, the operation of the present embodiment will be described.

  At the start of the boiling operation, first, it is confirmed whether the water temperature in the lower part of the hot water storage tank 21 detected by the thermistor 26e is lower than a predetermined temperature of 10 ° C.

  During the season in which frost formation is likely to occur in the evaporator 46 of the heat pump unit 13, the water temperature is low, and the water temperature of the water below the hot water storage tank 21 may be lower than 10 ° C. In such a case, the heat pump unit 13 is operated in a normal cycle (solid arrow in FIG. 1) in which the refrigerant circulates in the order of the compressor 43, the heat exchanger 44, the expansion valve 45, the evaporator 46, and the compressor 43. In addition, the three-way valve 39 for switching the intake port is switched to the lower connection port 25, the circulation pump 38 is driven, and the water in the lower part of the hot water storage tank 21 taken out from the water supply port 22 of the hot water storage tank 21 is passed through the heat exchanger 44 to the hot water storage tank. It is made to circulate so that it may take in in the lower connection port 25 of 21 lower part. As a result, the water collected from the outside air by the evaporator 46 of the heat pump unit 13 and boiled in the circulation path 35 is boiled by the heat exchanger 44, and the boiled hot water is taken into the lower part of the hot water storage tank 21. This boiling operation is continued until the water temperature in the lower part of the hot water storage tank 21 detected by the thermistor 26e reaches 10 ° C.

  When the water temperature at the bottom of the hot water storage tank 21 detected by the thermistor 26e reaches 10 ° C., the intake port switching three-way valve 39 switches from the lower connection port 25 to the upper connection port 23 or the intermediate connection port 24 to perform normal boiling operation. To do. Normally, the intake port switching three-way valve 39 switches to the upper connection port 23, hot water boiled by the heat pump unit 13 is taken into the upper part of the hot water storage tank 21 through the upper connection port 23, and downward from the upper part of the hot water storage tank 21. Store hot water sequentially.

  On the other hand, if the water temperature in the lower part of the hot water storage tank 21 detected by the thermistor 26e at the start of the boiling operation is 10 ° C. or higher, the normal boiling operation is performed. Therefore, when the normal boiling operation is performed, the water temperature in the lower part of the hot water storage tank 21 is maintained at 10 ° C. or higher.

  In addition, during the boiling operation, frost is generated in the evaporator 46 of the heat pump unit 13, and this frost detection is detected by the frost detection means 49, whereby the boiling operation by the heat pump unit 13 is temporarily stopped and removed. Switch to frost operation.

  In the defrosting operation, the heat pump unit 13 is operated in a reverse cycle in which the refrigerant circulates in the order of the compressor 43, the evaporator 46, the expansion valve 45, the heat exchanger 44, and the compressor 43 (broken arrows in FIG. 1). The intake port switching three-way valve 39 switches from the upper connection port 23 to the lower connection port 25 and drives the circulation pump 38 to remove the water in the lower part of the hot water storage tank 21 taken out from the water supply port 22 of the hot water storage tank 21 through the heat exchanger 44. After that, it is circulated so as to be taken into the lower connection port 25 at the lower part of the hot water storage tank 21. Thus, heat is collected from the water in the circulation path 35 by the heat exchanger 44 of the heat pump unit 13 to increase the temperature of the evaporator 46 and defrost.

  At the start of this defrosting operation, the hot water boiled in the previous boiling operation remains in the heat exchanger 44. Therefore, in order to collect the heat of this hot water, the circulation flow rate by the circulation pump 38 is reduced. And increase the efficiency of the defrosting operation. Thereafter, the circulation flow rate by the circulation pump 38 is controlled so that the water temperature detected by the hot water temperature detection sensor 51 at the outlet of the heat exchanger 44 becomes a predetermined circulation temperature set in advance. The predetermined circulation temperature is a temperature at which water whose temperature has been lowered through the heat exchanger 44 does not freeze in the circulation path 35 and can be reliably collected from the water by the heat exchanger 44.

  And if the frost detection by the frost detection means 49 is cancelled | released, a defrost operation will be stopped and it will switch to the normal boiling operation mentioned above.

  In this way, when defrosting is detected by frost detection, the heat pump unit 13 is operated by switching to the reverse cycle, water is taken out from the lower portion of the hot water storage tank 21 by circulation by the circulation means 34, and the hot water storage tank 21 of the hot water storage tank 21 is passed through the heat exchanger 44. By introducing the water into the lower connection port 25, the hot water stored in the upper part of the hot water storage tank 21 can be used to defrost using the water in the lower part of the hot water storage tank 21, and the temperature can be changed via the heat exchanger 44. By taking the lowered water into the lower part of the hot water storage tank 21, it is possible to prevent the water temperature in the lower part of the hot water storage tank 21 from rising, and to prevent the boiling efficiency of the heat pump unit 13 from being lowered during boiling after defrosting.

  Also, when the water temperature in the lower part of the hot water storage tank 21 is lower than a predetermined temperature at the time of boiling, the hot water boiled through the heat exchanger 44 by circulation by the circulation means 34 is taken into the lower connection port 25 of the hot water storage tank 21. By setting the temperature to a predetermined value, it is possible to prevent water whose temperature has been lowered through the heat exchanger 44 from being frozen in the circulation path 35 of the circulation means 34 during defrosting.

  Further, at the time of defrosting, the temperature of water passing through the heat exchanger 44 in the circulation path 35 is detected, and the circulation flow rate by the circulation pump 38 is controlled so that the water temperature becomes a predetermined circulation temperature, whereby the heat exchanger 44 It is possible to prevent the water whose temperature has been lowered through the freezing in the circulation path 35 from being frozen and reliably collect heat from the water by the heat exchanger 44.

It is a lineblock diagram of a hot-water supply device showing one embodiment of the present invention. It is a block diagram of a hot-water supply apparatus same as the above.

Explanation of symbols

11 Water heater
13 Heat pump unit
21 Hot water storage tank
22 Water inlet as outlet
23 Upper connection port as upper intake
25 Lower connection port as lower intake
26e Thermistor as a means of detecting water temperature
34 Circulation means
35 Circuit
38 Circulation pump
39 Inlet switching three-way valve as inlet switching means
42 Refrigerant circuit
43 Compressor
44 heat exchanger
46 Evaporator
47 Four-way valve
49 Frosting detection means
51 Hot water temperature detection sensor as temperature detection means
62 Boiling control means
63 Defrost control means

Claims (2)

A hot water storage tank provided with an outlet in the lower part and provided with an upper inlet and a lower inlet in at least the upper part and the lower part,
A heat pump unit having a refrigerant circuit in which a compressor, a heat exchanger and an evaporator are provided, and a four-way valve for switching the cycle to the refrigerant circuit;
Circulation means for circulating the water taken out from the lower outlet of the hot water storage tank so as to switch to one of the inlets through the heat exchanger of the heat pump unit;
Frost detection means for detecting frost formation of the evaporator of the heat pump unit;
At the time of boiling, the heat pump unit is operated in a normal cycle, water is taken out from the lower part of the hot water storage tank by circulation by the circulation means, and hot water boiled through the heat exchanger is taken into the upper intake port of the hot water storage tank. Upper control means;
At the time of frost detection by the frost detection means, the heat pump unit is operated by switching to a reverse cycle, water is taken out from the lower part of the hot water storage tank by circulation by the circulation means, and passed through the heat exchanger to the lower intake of the hot water storage tank. Defrost control means to be incorporated ;
Water temperature detecting means for detecting the water temperature of the lower part of the hot water storage tank,
The boiling control means is configured to remove hot water boiled through the heat exchanger by circulation by the circulation means when the water temperature detected by the water temperature detection means is lower than a predetermined temperature during boiling. Hot water boiled through the heat exchanger by circulation by the circulation means when the water temperature detected by the water temperature detection means is equal to or higher than a predetermined temperature, and taken into the upper intake of the hot water storage tank. A hot water supply device . The circulation means is an inlet switching that allows the hot water passing through the heat exchanger of the hot water storage tank to pass through the heat exchanger to each intake, and the hot water passing through the heat exchanger of this circulation path is switched to any one of the intakes. Means, a circulation pump provided in the circulation path for circulating hot water, and the temperature detection means for detecting the temperature of the hot water passed through the heat exchanger of the circulation path is provided in the circulation path,
Defrosting control means, said temperature water temperature detected by the detection means and controlling the circulating flow rate by the circulation pump to a predetermined circulation temperature claim 1 Symbol mounting of the water heater.

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