JP2010054145A - Heat pump water heater - Google Patents

Abstract

【Task】
It aims at providing the heat pump water heater which suppresses the fall of the heating efficiency by frost formation.
[Solution]
A heat pump water heater according to the present invention includes a compressor, a water refrigerant heat exchanger that exchanges heat between water and refrigerant, an expansion valve, and an air refrigerant heat exchanger that exchanges heat between air and refrigerant via a refrigerant pipe. Connected heat pump refrigerant circuit, water refrigerant heat exchanger, hot water mixing valve, hot water storage tank for storing hot water heated by the water refrigerant heat exchanger, hot water storage circuit connecting the in-machine circulation pump via water piping, and water supply Tank hot water supply circuit with metal fittings, hot water storage tank, hot water mixing valve, hot water mixing valve, flow rate adjustment valve, and hot metal fittings connected via water piping, compressor, expansion valve, hot water mixing valve, in-machine circulation pump, hot water mixing valve , And an operation control means for controlling the flow rate adjusting valve. The frost level is determined based on the detected frost condition of the air refrigerant heat exchanger, and the expansion valve is opened according to the determined frost level. Control the degree.
[Selection] Figure 2

Description

  The present invention relates to a heat pump water heater, and more particularly to a defrosting unit of an air refrigerant heat exchanger (evaporator).

  As a conventional heat pump water heater, a large-capacity hot water storage tank is installed like an electric water heater, and heat pump operation is performed using cheap electricity at a discounted night rate, and the water is boiled and stored in the hot water storage tank at night. There is a hot water storage heat pump water heater that uses hot water stored in the daytime (see, for example, Patent Document 1). Patent Document 1 is a hot water storage type heat pump water heater having a large capacity hot water storage tank, and performs heat pump operation once a day at night to store hot water in the hot water storage tank. At low temperatures in winter, the outdoor heat exchanger (evaporator) is frosted and the heating capacity is reduced. Therefore, when the outdoor heat exchanger reaches -5 ° C or lower, only the blower fan is stopped while the heat pump is operating. Then, the expansion valve is fully opened to defrost.

  On the other hand, in recent years, instantaneous heat pump water heaters have been developed that aim to drastically reduce the size of the hot water storage tank by directly supplying hot water heated by operating the heat pump even during the daytime when hot water is used. For example, see Patent Document 2). In Patent Document 2, hot water storage operation is performed in advance, and hot water (about 60 ° C.) is stored in a 60 to 100 L small hot water storage tank. When hot water is used, when the heating temperature of the heat pump does not reach an appropriate temperature (about 40 ° C.), hot water from the hot water storage tank is mixed with the heated water of the heat pump to supply hot water at an appropriate temperature. Thereafter, when the heating temperature by the heat pump operation reaches an appropriate temperature, the hot water supply from the hot water storage tank is stopped, and the appropriate temperature water (about 40 ° C.) heated by the heat pump operation is directly supplied. To circulate the high-temperature and high-pressure refrigerant discharged from the compressor directly to the evaporator (air refrigerant heat exchanger) without going through the condenser (water refrigerant heat exchanger) and pressure reducing device (expansion valve) at low temperatures in winter. The defrosting is performed by opening the bypass valve.

  In the conventional heat pump water heater, regarding the defrosting of the air refrigerant heat exchanger (evaporator), only the ambient temperature or the temperature of the air refrigerant heat exchanger is used in both the hot water storage heat pump water heater and the instantaneous heat pump water heater. The amount of frost formation was assumed. Moreover, after a large amount of frost is formed and the heating performance of the heat pump is greatly reduced, defrosting is performed by heat pump operation. However, even if the ambient temperature or the temperature of the air refrigerant heat exchanger is low, the amount of frost formation is small for a short time after the start of the heat pump operation, which is not the best method for detecting the amount of frost formation. Therefore, when the defrosting operation is performed even though the operation time is short and the frost amount is small, the defrosting operation may be started after the long time operation and the frost amount increases and the heating capacity decreases. There was room for improvement in efficiency in heating operation. Further, since the heat pump operation is performed without hot water supply at the time of defrosting, extra operating power of the compressor is consumed, which is a negative factor for energy saving.

JP 2003-90653 A JP 2003-279133 A

  This invention makes it a subject to provide the heat pump water heater which suppresses the fall of the heating efficiency by frost formation.

  In order to solve the above problems, a heat pump water heater according to the present invention includes a compressor, a water refrigerant heat exchanger that exchanges heat between water and a refrigerant, an expansion valve, and an air refrigerant heat that exchanges heat between air and refrigerant. A heat pump refrigerant circuit connected via a refrigerant pipe, a water refrigerant heat exchanger, a hot water mixing valve, a hot water storage tank for storing hot water heated by the water refrigerant heat exchanger, and an in-machine circulation pump via the water pipe Hot water storage circuit, water supply fitting, hot water storage tank, hot water supply mixing valve, hot water mixing valve, flow rate adjustment valve, hot water supply fitting connected via a water pipe, compressor, expansion valve, hot water supply mixing valve , An in-machine circulation pump, a hot and cold water mixing valve, and an operation control means for controlling the flow rate adjusting valve, and determining the frost level based on the detected frost condition of the air refrigerant heat exchanger, and the determined frost level To control the opening of the expansion valve

  ADVANTAGE OF THE INVENTION According to this invention, the heat pump water heater which suppresses the fall of the heating efficiency by defrost can be provided.

  Embodiments according to the present invention will be described below with reference to the drawings.

  An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a configuration diagram of a heat pump water heater according to the present embodiment. As an example, the present invention is applied to an instantaneous heat pump water heater.

  The heat pump water heater includes a heat pump refrigerant circuit 30, a hot water supply circuit 40, and an operation control means 50. The heat pump refrigerant circuit 30 is configured by a two-cycle system of a first refrigerant circuit 30a and a second refrigerant circuit 30b. In the first refrigerant circuit 30a and the second refrigerant circuit 30b, refrigerant side heat transfer tubes 2a and 2b, expansion valves 3a and 3b, air refrigerant heat exchange disposed in the compressors 1a and 1b and the water refrigerant heat exchanger 2, respectively. The containers 4a and 4b are sequentially connected via the refrigerant pipe, and the refrigerant is sealed in the refrigerant pipe.

  The compressors 1a and 1b are capable of capacity control, and are operated with a large capacity when supplying a large amount of hot water. The compressors 1a and 1b can control the rotation speed from a low speed (for example, 700 rotations / minute) to a high speed (for example, 7000 rotations / minute) by PWM control, voltage control (for example, PAM control) and combination control thereof.

  The water refrigerant heat exchanger 2 includes refrigerant side heat transfer tubes 2a and 2b and water supply side heat transfer tubes 2c and 2d, and performs heat exchange between the refrigerant side heat transfer tubes 2a and 2b and the water supply side heat transfer tubes 2c and 2d. .

  The expansion valves 3a and 3b use electric expansion valves that have a quick response when adjusting the opening. The expansion valves 3a and 3b depressurize the medium temperature and high pressure refrigerant sent via the water refrigerant heat exchanger 2 and send it to the air refrigerant heat exchangers 4a and 4b as a low pressure refrigerant that easily evaporates. The expansion valves 3a and 3b adjust the refrigerant circulation amount in the heat pump refrigerant circuit by changing the opening degree of the refrigerant passage, and increase the opening degree so that the medium temperature refrigerant is supplied to the air refrigerant heat exchangers 4a and 4b in a large amount. It also functions as a defroster for sending and melting frost.

  The air refrigerant heat exchangers 4a and 4b take in outside air by the rotation of the blower fans 5a and 5b, exchange heat between the air and the refrigerant, and absorb heat from the outside air.

  The hot water supply circuit 40 includes a water circulation circuit for performing hot water storage, direct hot water supply, tank hot water supply, bath hot water filling, and bath reheating. The hot water storage circuit is a water circuit for storing high-temperature water in the hot water storage tank 16 by the tank boiling operation. The hot water storage circuit is configured by sequentially connecting a hot water storage tank 16, an in-machine circulation pump 17, a hydrothermal AC sensor 10, water supply side heat transfer pipes 2c and 2d, a hot water supply mixing valve 11, and a hot water storage tank 16 via a water pipe.

  The direct hot water supply circuit includes a water supply fitting 6, a pressure reducing valve 7, a water supply water amount sensor 8, a water supply side check valve 9, a water heat AC amount sensor 10, water supply side heat transfer tubes 2c and 2d, a hot water supply mixing valve 11, a hot water mixing valve 12, A flow rate adjusting valve 13 and a kitchen tapping metal fitting 14 are sequentially connected via a water pipe. The water supply fitting 6 is connected to a water supply source such as a water supply. The kitchen tapping metal fitting 14 is connected to a kitchen faucet 15 or the like.

  The tank hot water supply circuit includes a water supply fitting 6, a pressure reducing valve 7, a water supply amount sensor 8, a water supply side check valve 9, a hot water storage tank 16, a hot water supply mixing valve 11, a hot water mixing valve 12, a flow rate adjusting valve 13, and a kitchen tapping metal fitting 14. Sequentially connected via water piping.

  The bath hot water filling circuit includes a water supply fitting 6, a pressure reducing valve 7, a water supply water amount sensor 8, a water supply side check valve 9, a water heat AC amount sensor 10, water supply side heat transfer tubes 2c and 2d, a hot water supply mixing valve 11, and a hot water mixing valve 12. , Flow adjustment valve 13, bath pouring valve 18, flow switch 19, bath circulation pump 20, water level sensor 21, bath inlet / outlet metal fitting 22, bath circulation adapter 23, and bathtub 24 are sequentially connected via a water pipe. The Moreover, it connects so that it can supply hot water to the bath faucet 25 and the shower (not shown) from the bath entry / exit metal fitting 22 with the bathtub 24. During bath hot water filling, hot water supply from the hot water storage tank 16 to the bathtub 24 is performed in a range where the hot water amount in the hot water storage tank 16 does not fall below the minimum required amount as well as direct hot water supply by the bath hot water filling circuit.

  The bath memory circuit includes a bath 24, a bath circulation adapter 23, a bath inlet / outlet fitting 22, a water level sensor 21, a bath circulation pump 20, a flow switch 19, a bath water heat transfer pipe 23b of a bath heat exchanger 27, and a bath outlet fitting 26. The bath circulation adapter 23 and the bathtub 24 are sequentially connected via a water pipe. At the time of bathing, the hot water heated by the water / refrigerant heat exchanger 2 is operated by operating the heat pump operation and the in-machine circulation pump 17 together with the water circulation of the bathtub water by the bath chasing circuit and opening the hot water on-off valve 28. It is made to circulate through the hot water heat exchanger tube 27a provided in the heat exchanger 27 for baths, heat is exchanged between the hot water heat exchanger tube 27a and the bath water heat exchanger tube 27b, and the bath is reheated.

  Next, the operation control means 50 performs the operation / stop of the heat pump refrigerant circuit 30 and the rotation speed control of the compressors 1a, 1b and the expansion valves 3a, 3b according to the operation setting of the kitchen remote controller 51 or the bath remote controller 52. By adjusting the opening of the refrigerant, the operation / stop of the in-machine circulation pump 17, the bath circulation pump 20, and the hot water mixing valve 11, the hot water mixing valve 12, the flow rate adjusting valve 13, the bath pouring valve 18, and the hot water on / off valve 28, Hot water storage operation, direct hot water supply operation, tank hot water operation, bath hot water operation, and bath memorial operation are performed. Here, at the start of operation, the number of revolutions of the compressors 1a and 1b is gradually increased, and the operation is performed at a predetermined high speed to shorten the heating start-up time. When performing bath chasing operation with a light heat load, control is performed to operate at a low speed corresponding to the heating temperature.

  Moreover, the operation control means 50 has a defrosting operation control means, and the defrosting operation control means detects the frosting condition in the heat pump operation, determines the frosting level based on the detection result of the frosting condition, and determines the determined frosting. The opening of the expansion valve is controlled based on the level, and the combination of heat pump operations is controlled.

  Further, the heat pump water heater includes tank thermistors 15a to 16e for detecting the hot water storage temperature and amount of hot water storage tank 16, an ambient temperature thermistor (not shown) for detecting the ambient temperature of the air refrigerant heat exchanger, and air refrigerant. An air heat exchanger thermistor that detects the temperature of the heat exchanger, a thermistor (not shown) that detects the temperature of each part, a pressure sensor (not shown) that detects the discharge pressure of the compressors 1a and 1b, and the water level in the bathtub 24 A water level sensor 21 or the like is provided. These detection signals are input to the operation control means 50, and the operation control means 50 controls each device based on these detection signals.

  Incidentally, at the beginning of the hot water supply operation, the hot water mixing valve 11 is opened between the water / refrigerant heat exchanger 2 side and the hot / cold water mixing valve 12 side and between the hot water storage tank 16 side and the hot / cold water mixing valve 12 side. Hot water is supplied from both the heat exchanger 2 and the hot water storage tank 16. Thereafter, when the heating temperature in the water refrigerant heat exchanger 2 by the heat pump reaches the hot water supply temperature (about 42 ° C.), the hot water storage tank 16 side and the hot water mixing valve 12 side are closed, and hot water supply is only from the water refrigerant heat exchanger 2. To do.

  The hot water on / off valve 28 is provided between the water-refrigerant heat exchanger 2 and the bath heat exchanger 27. The hot water on / off valve 28 is opened when the bath is replenished to perform the bath retreat operation, and at other times the water circuit is closed. Thus, heat leakage from the water refrigerant heat exchanger 2 to the bath heat exchanger 27 is prevented.

  Further, the water supply side check valve 9 allows water to flow only in one direction and prevents backflow.

  Next, about the operation | movement operation | movement of the heat pump water heater which concerns on a present Example, referring the heat pump refrigerant circuit 30 and the hot water supply circuit 40 of FIG. 1, the defrost operation flowchart of FIG. 2, the frost level determination criteria table | surface of FIG. This will be described based on the defrosting operation means of FIG.

  FIG. 2 is a flowchart of the defrosting operation according to the present embodiment, and shows a hot water supply operation and subsequent defrosting operation when the kitchen faucet 15 is opened and hot water is used. When the kitchen faucet 15 is opened and the use of hot water begins (step 61), the operation control means 50 operates the compressors 1a and 1b to start the operation of the refrigerant circuit 30 of the heat pump, and the water supply fitting 6 and the pressure reducing valve 7 , Water supply amount sensor 8, water supply side check valve 9, hydrothermal AC amount sensor 10, water supply side heat transfer pipes 2c, 2d, hot water mixing valve 11, hot water mixing valve 12, flow rate adjustment valve 13, kitchen tap metal fitting 14, kitchen faucet The direct hot water supply operation is started by the 15 direct hot water supply circuits (step 62). Simultaneously with step 62, the water supply fitting 6, the pressure reducing valve 7, the water supply water amount sensor 8, the water supply side check valve 9, the hot water storage tank 16, the hot water supply mixing valve 11, the hot water mixing valve 12, the flow rate adjusting valve 13, and the kitchen tapping metal fitting 14 The tank hot water supply operation is started by the tank hot water supply circuit of the kitchen faucet 15 (step 63).

  Here, the heat pump refrigerant circuit 30 sends the high-temperature and high-pressure refrigerant compressed by the compressors 1a and 1b to the refrigerant-side heat transfer tubes 2a and 2b of the water-refrigerant heat exchanger 2, and the water flowing in the water supply-side heat transfer tubes 2c and 2d. Is heated and circulated to the hot water supply mixing valve 11 side. However, at the time of start-up immediately after operation, the refrigerant sent to the water-refrigerant heat exchanger 2 is not sufficiently high-temperature and high-pressure, the temperature is low, and the entire water-refrigerant heat exchanger 2 is cooled. not enough. Accordingly, a tank hot water supply for supplying high-temperature water from the hot water storage tank 16 is required (step 63). In other words, since it takes several minutes for the heating capacity of the heat pump operation to reach an appropriate temperature state, the operation control means 50 supplies the appropriate temperature water from the kitchen faucet 15, and until the temperature reaches the appropriate temperature state from the start of operation, the compressor The rotational speed of 1a, 1b is made higher than usual, and hot water is supplied from the hot water storage tank 16 (step 63).

  Then, the heating temperature determination by the heat pump operation (step 64) is performed, and if it is less than the specified value, the parallel operation of the direct hot water supply and the tank hot water supply is continued, and if the specified value or more, the tank hot water supply is stopped (step 65), Hot water is supplied by direct operation of direct hot water supply (step 66).

  The operation control means 50 operates the hot water supply mixing valve 11 to increase the tank hot water supply amount when the mixed hot water temperature after the hot water supply mixing valve 11 is considerably lower than the appropriate temperature, and to decrease the tank hot water supply amount as the temperature approaches the appropriate temperature. Adjust the flow rate ratio to make it suitable temperature. When the mixed hot water temperature after passing through the hot water mixing valve 11 is higher than the appropriate temperature, the hot water supply temperature to the use terminal can also be adjusted by adjusting the amount of water supplied from the hot water mixing valve 12.

  Therefore, the role of the hot water storage tank 16 is an auxiliary one at the time of start-up until the heating capacity of the heat pump operation reaches a temperature sufficient for the hot water supply temperature, and the capacity of the heat pump refrigerant circuit 30, particularly the compressors 1a and 1b. The larger the output, the shorter the startup time and the smaller the hot water storage tank 16.

  Moreover, in order to cope with simultaneous use of a plurality of places by using only direct hot water supply such as performing hot water bathing at the same time as kitchen hot water supply, the capacity of the compressors 1a and 1b is 5 kW generally used in the conventional hot water storage system. It is desirable to increase it to about 20 kW with respect to the degree. However, it is extremely difficult not only to develop a new compressor but also to make a new study for each component of the heat pump refrigerant circuit 30. Therefore, in this embodiment, the two-cycle heat pump systems 30a and 30b using two compressors approximately twice as large as those of the conventional compressor are used, and the reliability of the conventional technology and the results are ensured. In addition, if the capacity | capacitance of a compressor is enough, this invention is applicable also to a 1 cycle heat pump system.

  Next, when the faucet is closed and the use of hot water is completed (step 67), the direct hot water supply operation is stopped if only the direct hot water supply operation is performed, and the direct hot water supply operation is performed when the tank hot water supply operation and the direct hot water supply operation are used together. Both the tank hot water supply operation is stopped (step 68).

  Furthermore, the operation control means 50 detects the ambient temperature of the air refrigerant heat exchangers 4a and 4b, the temperature of the air refrigerant heat exchangers 4a and 4b, and the operation time of the heat pump, which are frosting conditions (step 69). The frost level is determined based on the detection result (step 70). Thereafter, a defrosting operation corresponding to the determined three frost levels is performed (steps 71 to 73).

  Here, with reference to FIG. 3 and FIG. 4, an example of frost level determination criteria and a defrosting operation means will be described. According to the inventor's test results, frost formation by heat pump operation has an absolute humidity sufficient for frost formation, and the ambient temperature at which the air refrigerant heat exchanger temperature becomes 0 ° C. or lower is about −7 ° C. to + 7 ° C. It becomes remarkable between ° C. That is, when the ambient temperature is + 7 ° C. or higher, the temperature of the air refrigerant heat exchangers 4a and 4b is about 0 ° C. or higher, so that water droplets are formed and frost formation does not occur. Further, when the ambient temperature is −7 ° C. or lower, the absolute humidity is lowered and the moisture in the air is small, so that the amount of frost formation is also small.

  FIG. 3 is a diagram illustrating a relationship between the frost level determination condition and the frost level determination criterion. The ambient temperature, the temperature of the air refrigerant heat exchangers 4a and 4b, and the heat pump operating time are each divided into three stages, and by combining these, the frost level is divided into three stages A, B, and C in the order of decreasing frost amount. Break down. For example, when the ambient temperature is + 7 ° C. or higher or the air refrigerant heat exchanger temperature is 0 ° C. or higher, it is determined that the level A has a small frost formation amount even if the heat pump operation time is 30 minutes or longer. Further, when the ambient temperature is −7 ° C. or lower or the air refrigerant heat exchanger temperature is 0 to −5 ° C., the temperature is classified into levels A, B, and C according to the heat pump operation time. If the ambient temperature at which frost formation is most likely is −7 to + 7 ° C. or the air refrigerant heat exchanger temperature is −5 ° C. or less, if the heat pump operation time is 10 minutes or less, the level B exceeds 10 minutes. Judged as level C.

  In the present embodiment, the frost level determination criterion is classified into three stages according to the combination of the ambient temperature, the air refrigerant heat exchanger temperature, and the heat pump operating time, but may be further finely classified. For example, the heat pump operation time can be 10 minutes or less, 10 to 30 minutes, 30 to 50 minutes, or 50 minutes or more.

  Next, the defrosting operation (steps 71 to 73) corresponding to the frosting level is performed to effectively utilize the residual heat from the heat pump operation (step 74). In the case of level A where frost is not generated, the water-refrigerant heat exchanger is kept warm, and in the case of level B where the amount of frost formation is relatively small or C where there is a large amount of frost formation, there is no frost formation due to defrosting. Can be achieved. (Step 76).

  FIG. 4 is a diagram showing the relationship between the frost level and the defrosting operation means. In the case of level A where frost is hardly formed, the heat pump is not operated, the expansion valves 3a and 3b are fully closed, and the high-temperature to medium-temperature refrigerant in the water-refrigerant heat exchanger 2 is not circulated. By maintaining the high temperature state as long as possible, the effect of accelerating the heating rise at the start of the next operation is obtained.

  In the case of level B where the amount of frost formation is relatively small, the heat pump is not operated, and the expansion valves 3a and 3b are opened halfway to circulate the high temperature residual heat refrigerant in the water refrigerant heat exchanger 2 to the air refrigerant heat exchangers 4a and 4b. The air efficiency is improved by improving the heat exchange performance of the air refrigerant heat exchangers 4a and 4b at the start of the next operation.

  In the case of level C with a large amount of frost formation, it is necessary to surely defrost because there is a risk of freezing as well as frost formation. Therefore, the expansion valves 3a and 3b are fully opened, and the air refrigerant heat exchangers 4a and 4b are surely defrosted by performing the heat pump operation, and the air refrigerant heat exchangers 4a and 4b are close to the initial stage at the start of the next operation. By improving the heat exchange performance in the state, the heating efficiency is improved. Moreover, in the conventional heat pump water heater, since the start of the defrosting is determined only by the temperature, the heat pump operation time may not be defrosted even for nearly 1 hour, but in this example, the level is 30 minutes or less. It is determined that the heat pump is defrosted by judging C, and the deterioration of the heating performance due to frost formation can be eliminated at an early stage.

  The opening degree of the expansion valves 3a and 3b also varies depending on the valve diameters of the expansion valves 3a and 3b. Therefore, in the present embodiment, the opening degree of the expansion valves 3a and 3b is divided into three stages, but is not limited to this. For example, the opening degree of the expansion valves 3a and 3b may be divided into five stages of almost fully closed, about 1/4 open, about 1/2, about 3/4 open, and almost fully open.

  As described above, in this embodiment, the frost level is determined based on the detected frost condition of the air refrigerant heat exchanger, and the opening degree of the expansion valve is controlled in accordance with the determined frost level. Therefore, since defrosting according to a frost level can be performed, the fall of the heating efficiency by frost formation can be suppressed. Specifically, when the frost level is low, the opening degree of the expansion valve is fully closed or half-open, and the residual heat defrosting is performed. When the frost level is high, the opening degree of the expansion valve is fully opened and the residual heat defrosting is performed. By defrosting early, the fall of the heating efficiency by frost formation is suppressed. Further, the frosting level can be set to at least three levels, and the opening degree of the expansion valve can be controlled to at least three levels of fully closed, half open, and fully open in accordance with the determined frost level. Further, not only the opening degree of the expansion valve but also the operation / stop of the heat pump is controlled in accordance with the determined frost level. By performing defrosting of the air refrigerant heat exchangers 4a and 4b every time the heat pump operation is interrupted, it is possible to improve the performance at the next heating start-up, thereby improving the heating efficiency and saving energy.

  As described above, according to the present embodiment, by combining the defrosting means for determining whether the expansion valve opening degree and the heat pump operation are possible or not according to the frost level determination criterion, the natural defrost due to the heat pump residual heat is utilized, and the defrosting is performed. The heat pump operation for the heat pump is suppressed to the minimum necessary, and the residual heat defrosting is performed every time the heat pump operation is interrupted, so that the air refrigerant heat exchanger in the next heating operation is in the best condition to improve the heating efficiency and save energy be able to.

  In this embodiment, at least three stages of frost level determination criteria are provided based on the ambient temperature, the air refrigerant heat exchanger, and the heat pump operation time, and the expansion valve opening and At least three stages of defrosting operation means are set by a combination of heat pump operations. Such an embodiment according to the present invention has a great effect particularly in an instantaneous heat pump water heater having a large number of intermittent heat pumps. However, the present invention is not limited to the instantaneous heat pump water heater, and even in the hot water storage heat pump water heater, there is a case where the hot water storage operation is performed other than at night in order to reduce the size of the hot water storage tank and save energy. The effect similar to the case where it applies to a type heat pump water heater can be acquired.

The block diagram of a heat pump water heater. The flowchart which shows a defrost operation. The figure which shows the relationship between frost level determination conditions and frost level determination criteria. The figure which shows the relationship between a frost formation level and a defrost driving | operation means.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a, 1b Compressor 2 Water refrigerant | coolant heat exchanger 3a, 3b Expansion valve 4a, 4b Air refrigerant | coolant heat exchanger 6 Water supply metal fitting 7 Pressure reducing valve 8 Water supply water quantity sensor 11 Hot water supply mixing valve 12 Hot water mixing valve 13 Flow rate adjustment valve 14 Kitchen hot water supply metal fitting 15 Kitchen Faucet 16 Hot Water Storage Tank 17 In-machine Circulation Pump 20 Bath Circulation Pump 24 Bathtub 25 Bath Faucet 27 Bath Heat Exchanger 28 Hot Water On / Off Valve 30 Heat Pump Refrigerant Circuit 40 Hot Water Supply Circuit 50 Operation Control Means

Claims (8)

A heat pump refrigerant circuit in which a compressor, a water refrigerant heat exchanger that performs heat exchange between water and refrigerant, and an expansion valve, an air refrigerant heat exchanger that performs heat exchange between air and refrigerant, are connected via a refrigerant pipe;
A hot water storage circuit in which the water refrigerant heat exchanger, a hot water mixing valve, a hot water storage tank for storing hot water heated by the water refrigerant heat exchanger, and an in-machine circulation pump are connected via a water pipe;
A tank hot water circuit in which a water supply fitting, the hot water storage tank, a hot water supply mixing valve, a hot water mixing valve, a flow rate adjustment valve, and a hot water supply fitting are connected via a water pipe;
An operation control means for controlling the compressor, the expansion valve, the hot water mixing valve, the in-machine circulation pump, the hot water mixing valve, and the flow rate adjustment valve;
A heat pump water heater that determines a frost level based on the detected frost condition of the air refrigerant heat exchanger, and controls the opening of the expansion valve in accordance with the determined frost level. A heat pump refrigerant circuit in which a compressor, a water refrigerant heat exchanger that performs heat exchange between water and refrigerant, and an expansion valve, and an air refrigerant heat exchanger that performs heat exchange between air and refrigerant are connected via a refrigerant pipe;
A hot water storage circuit in which the water refrigerant heat exchanger, a hot water mixing valve, a hot water storage tank for storing hot water heated by the water refrigerant heat exchanger, and an in-machine circulation pump are connected via a water pipe;
A tank hot water supply circuit in which a water supply fitting, the hot water storage tank, a hot water supply mixing valve, a hot water mixing valve, a flow rate adjustment valve, and a hot water supply fitting are connected via a water pipe;
An operation control means for controlling the compressor, the expansion valve, the hot water supply mixing valve, the in-machine circulation pump, the hot water mixing valve, and the flow rate adjustment valve;
The frosting condition of the air refrigerant heat exchanger is detected, the frosting level is determined from the detection result of the frosting condition and the frosting level determination criterion, and the expansion valve of the expansion valve corresponding to the determined frosting level is determined. A heat pump water heater that controls the opening.   In Claim 1 or 2, the said frost level is determined to at least 3 steps | paragraphs, and the opening degree of the said expansion valve is controlled to at least 3 steps | paragraphs of full open, half open, and full open corresponding to the determined frost level. Heat pump water heater.   In any one of Claim 1 thru | or 3, when controlling the opening degree of the said expansion valve fully open corresponding to the said determined frost level, a heat pump is drive | operated and it respond | corresponds to the determined frost level A heat pump water heater that stops the heat pump when the opening degree of the expansion valve is controlled to be fully closed or half open.   The heat pump water heater according to any one of claims 1 to 4, wherein the frosting conditions are an ambient temperature of the air refrigerant heat exchanger, a temperature of the air refrigerant heat exchanger, and a continuous operation time of the heat pump.   6. The frost level according to claim 5, wherein the ambient temperature of the air refrigerant heat exchanger that is the frosting condition is divided into at least 7 degrees C, 7 degrees C to -7 degrees C, and -7 degrees C or less. Determine the heat pump water heater.   7. The frost formation according to claim 5, wherein the temperature of the air refrigerant heat exchanger which is the frosting condition is divided into three stages of at least 0 ° C., 0 ° C. to −5 ° C., and −5 ° C. or less. A heat pump water heater that determines the level.   In any one of Claims 5 thru | or 7, the continuous operation time of the said heat pump which is the said frost formation conditions is divided into three steps of at least 10 minutes or less, 10 minutes-30 minutes, 30 minutes or more, and the said frost level Determine the heat pump water heater.

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