JP5139211B2 - Heat pump type water heater - Google Patents

Description

  The present invention relates to a heat pump type hot water supply apparatus for heating hot water.

  Conventionally, in this type of heat pump type hot water supply apparatus, as disclosed in Patent Document 1, a heat pump cycle in which a compressor, a water-refrigerant heat exchanger, an expansion valve, and an air heat exchanger are annularly connected, and hot water for hot water supply are provided. A hot water storage tank for storing, a heating circulation circuit that connects the hot water storage tank and the water / refrigerant heat exchanger so that hot water can circulate through a circulation pump, a discharge temperature sensor that detects a refrigerant temperature discharged from the compressor, and the discharge temperature There is one in which the opening degree of the expansion valve is controlled so that the temperature detected by the sensor becomes a target value.

JP 2005-16947 A

  However, this conventional heat pump type hot water supply apparatus has a tendency to stabilize in a state where the compressor rotation speed is high and the expansion valve opening is small because the evaporation capacity in the air heat exchanger is small in winter. Depending on the frosting condition, the evaporation capacity of the air heat exchanger may further decrease. When the evaporation capacity decreases, the frequency of the compressor increases so as to maintain a constant heating capacity, and the discharge pressure becomes high.

  Under such circumstances, when the detected temperature of the discharge temperature sensor decreases from the target value, the expansion valve is operated to close the opening, but when the operation amount is large, the discharge pressure of the compressor becomes higher. There was a possibility that a load exceeding the allowable torque of the compressor would occur, causing the compressor to step out and stop abnormally.

  Therefore, in order to solve the above problems, the present invention provides a heat pump cycle in which a compressor, a water refrigerant heat exchanger, an expansion valve, and an air heat exchanger are connected in an annular shape, and a refrigerant temperature discharged from the compressor. A discharge temperature sensor for detecting the heat, a heat exchange water pipe and a heat exchange hot water pipe connected to the water side of the water refrigerant heat exchanger, and a heat refrigerant hot water pipe provided in the heat exchange hot water pipe and heated by the water refrigerant heat exchanger A boiling temperature sensor for detecting the temperature of the heated hot water, and an operation amount of a valve opening corresponding to a temperature difference between a temperature detected by the discharge temperature sensor and a predetermined target discharge temperature to the expansion valve at predetermined intervals. And controlling the opening and closing of the expansion valve, and a control device for increasing and decreasing the frequency of the compressor so that the detected temperature of the boiling temperature sensor becomes a desired boiling temperature, the control device, Expansion valve opening closed below a certain level While there, and the frequency of the compressor When it is higher than a predetermined frequency, the operation amount of the closing direction of the expansion valve at one cycle was limited smaller than usual.

  Further, in claim 2, a heat pump cycle in which a compressor, a water refrigerant heat exchanger, an expansion valve, and an air heat exchanger are connected in an annular shape, a discharge temperature sensor that detects a refrigerant temperature discharged from the compressor, and the heat pump A discharge pressure sensor for detecting the pressure on the high pressure side of the cycle, a heat input water pipe and a heat exchange hot water pipe connected to the water side of the water refrigerant heat exchanger, and the water provided in the heat exchange hot water pipe A boiling temperature sensor for detecting the temperature of hot water heated by the refrigerant heat exchanger, and an operation amount of a valve opening corresponding to a temperature difference between a detected temperature of the discharge temperature sensor and a predetermined target discharge temperature at a predetermined cycle A controller for increasing and decreasing the frequency of the compressor so that the detected temperature of the boiling temperature sensor becomes a desired boiling temperature, and is provided to the expansion valve every time to control the opening and closing of the expansion valve, The opening of the expansion valve is When the discharge pressure detected by the discharge pressure sensor is equal to or higher than a predetermined pressure, the operation amount in the closing direction of the expansion valve in one cycle is limited to be smaller than usual. .

  Further, in claim 3, a heat pump cycle in which a compressor, a water refrigerant heat exchanger, an expansion valve, and an air heat exchanger are connected in an annular shape, a discharge temperature sensor that detects a refrigerant temperature discharged from the compressor, and an outside air temperature An outside air temperature sensor for detecting water, a heat input water pipe and a heat exchange hot water pipe connected to the water side of the water refrigerant heat exchanger, and a heat exchange hot water pipe provided in the heat exchange hot water pipe and heated by the water refrigerant heat exchanger A boiling temperature sensor for detecting the temperature of the heated hot water, and an operation amount of a valve opening corresponding to a temperature difference between a temperature detected by the discharge temperature sensor and a predetermined target discharge temperature to the expansion valve at predetermined intervals. And a control device for increasing / decreasing the frequency of the compressor so that the detected temperature of the boiling temperature sensor becomes a desired boiling temperature. Is closed below a certain level, One, the outside air temperature detected by the outside air temperature sensor is not more than a predetermined outside air temperature, the amount of operation of the closing direction of the expansion valve at one cycle was limited smaller than usual.

  Moreover, in Claim 4, the heat pump cycle which connected the compressor, the water refrigerant | coolant heat exchanger, the expansion valve, and the air heat exchanger cyclically | annularly, the discharge temperature sensor which detects the refrigerant | coolant temperature discharged from the said compressor, and the said water A heat exchanger water pipe and a heat exchanger hot water pipe connected to the water side of the refrigerant heat exchanger, and a boiling point for detecting the temperature of the hot water provided in the heat exchanger hot water pipe and heated by the water refrigerant heat exchanger A temperature sensor and an opening / closing control of the expansion valve by giving an operation amount of a valve opening corresponding to a temperature difference between a detected temperature of the discharge temperature sensor and a predetermined target discharge temperature to the expansion valve every predetermined period A controller for increasing or decreasing the frequency of the compressor so that the detected temperature of the boiling temperature sensor becomes a desired boiling temperature, and when the opening of the expansion valve is closed below a certain level, And the boiling temperature is higher than the specified temperature When the operation amount of the closing direction of the expansion valve at one cycle was limited smaller than usual.

  According to the present invention, in a heavy load such as in winter, the operation amount in the closing direction of the expansion valve opening is limited to a small value, so that the increase in the torque of the compressor becomes slow and exceeds the allowable torque of the compressor. This prevents the compressor from stepping out and stops abnormally, and restricts the opening of the expansion valve only in the closing direction, so there is no restriction when operating the expansion valve in the opening direction. Even if the target value exceeds the target value, the discharge temperature can be quickly returned to the target value. In a normal load state, the discharge temperature of the refrigerant can be quickly reached the target value by normally controlling the opening degree of the expansion valve, and an efficient operation can be performed.

Next, a heat pump hot water supply apparatus according to an embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 1, 1 is a hot water storage tank unit having a hot water storage tank 2 for storing hot water, 3 is a heat pump heating means for heating hot water in the hot water storage tank 2, and 4 is connected to the lower part of the hot water storage tank 2. A heat circulation circuit comprising a heat exchange water pipe 5 and a heat exchange hot water pipe 6 connected to the upper part of the hot water storage tank 2, and 7 a water supply pipe connected to the lower part of the hot water storage tank 2 for supplying water to the hot water storage tank 2. , 8 is a discharge pipe connected to the upper part of the hot water storage tank 2 for discharging hot water stored in the hot water.

  9 is a water supply bypass pipe branched from the water supply pipe 7, 10 is a mixing valve that mixes hot water from the hot water discharge pipe 8 and water from the water supply bypass pipe 9 to make hot water at a hot water supply set temperature, and 11 is mixed by the mixing valve 10 A plurality of hot water supply temperature sensors 12 for detecting a hot water supply temperature later, a plurality of hot water storage temperature sensors 12 for detecting the temperature of hot water in the hot water storage tank 2, and a plurality of sensors 12 in the hot water storage tank unit 1. Is a hot water storage control means for controlling the operation of each device.

  The heat pump heating means 3 includes a compressor 14 that compresses refrigerant, a water refrigerant heat exchanger 15 that exchanges heat between the high-temperature and high-pressure refrigerant and hot water in the hot water storage tank 2, and a water refrigerant heat exchanger 15 that has passed through. A heat pump cycle 18 in which an expansion valve 16 serving as a decompressor for decompressing the refrigerant and an air heat exchanger 17 serving as an evaporator for evaporating the low-temperature and low-pressure refrigerant from the expansion valve 16 are annularly connected by a refrigerant pipe; A heating circulation pump 19 is provided in the middle of the heating circulation circuit 4 on the water side of the heat exchanger 15 to circulate hot water in the hot water storage tank 2. Here, the water-refrigerant heat exchanger 15 is a counter-flow heat exchanger in which the flow direction of the refrigerant and the flow direction of the water to be heated are opposed, and the expansion valve 16 is driven by a stepping motor.

  A discharge temperature sensor 20 is provided between the compressor 14 and the water refrigerant heat exchanger 15 to detect the discharge temperature of the refrigerant, and 21 is provided between the water refrigerant heat exchanger 15 and the expansion valve 16. An outflow temperature sensor for detecting an outflow temperature from the water refrigerant heat exchanger 15, 22 is provided on the air inlet side of the air heat exchanger 17, an outside air temperature sensor for detecting the outside air temperature, and 23 is a water refrigerant heat exchanger 15. The water temperature sensor detects the water temperature on the water side of the water refrigerant, 24 is a temperature sensor for detecting the water temperature of the water refrigerant heat exchanger 15, and 25 is a pressure for detecting the pressure on the high pressure side of the heat pump cycle 18. It is a sensor.

  Reference numeral 26 denotes a heating control means for receiving the output of each sensor in the heat pump heating means 3 and controlling the operation of each device. The heating control means 26 is communicably connected to the hot water storage control means 13. This constitutes a control device for controlling the hot water supply device.

Next, the operation of this embodiment will be described.
When hot water is supplied, when a user opens a faucet (not shown), city water flows from the water supply pipe 7 at the bottom of the hot water tank 2 and is boiled from the upper part of the hot water tank 2 and stored in the midnight hours. The hot water that is present is poured into the tap pipe 8. Then, hot water from the hot water discharge pipe 8 and city water from the feed water bypass pipe 9 are mixed by the mixing valve 10. At this time, the mixing ratio of the mixing valve 10 is adjusted so that the hot water temperature after mixing detected by the hot water temperature sensor 11 becomes the hot water set temperature set by a remote controller (not shown) or the like. Hot water is supplied from the faucet.

  In the midnight time zone, the hot water storage control means 13 instructs the heating control means 26 to start a boiling operation so as to start the boiling operation so that the hot water in the hot water storage tank 2 reaches a predetermined target boiling temperature Tset. Then, the heating control means 26 starts driving the compressor 14 and the heating circulation pump 19, sets the target boiling temperature Tset + a constant value as the target discharge temperature TD, and the discharge temperature of the refrigerant detected by the discharge temperature sensor 20 The opening degree of the expansion valve 16 is controlled so as to reach the target discharge temperature TD. And the temperature of the hot water heated by the water-refrigerant heat exchanger 15 detected by the boiling temperature sensor 24 is controlled to the target boiling temperature Tset at the same time as controlling the rotation number of the heating circulation pump 19 to a predetermined rotation number. Thus, the frequency of the compressor 14 is fed back and controlled to increase or decrease.

  When the boiling temperature detected by the boiling temperature sensor 24 tends to decrease, the heating control means 26 increases the frequency of the compressor 14 and at the same time the refrigerant discharge temperature detected by the refrigerant discharge temperature sensor 20 also decreases. Therefore, the expansion valve 16 is operated in the closing direction. Conversely, when the boiling temperature tends to increase, the frequency of the compressor 14 is decreased, and at the same time, the refrigerant discharge temperature detected by the refrigerant discharge temperature sensor 20 is also increasing, so that the expansion valve 16 is opened. To operate.

  Here, the predetermined target boiling temperature Tset is calculated by the hot water storage control means 13 so as to ensure the predicted amount of the hot water supply amount on the next day from the actual hot water supply results such as the maximum value and the average value of the past hot water supply amount. The temperature is determined in the range of 65 ° C to 90 ° C.

  Then, as the boiling operation proceeds, the water in the lower part of the hot water storage tank 2 is circulated to the heat pump type heating means 3, and the hot water heated from the upper part of the hot water storage tank 2 to the target boiling temperature Tset is stored in a stacked state. Is done. The hot water storage temperature sensor 12 detects that the required amount of hot water has been boiled in the hot water storage tank 2, or the incoming water temperature Twi detected by the incoming water temperature sensor 23 of the heat pump heating means 3 is higher than a predetermined high temperature that is difficult to boil up. Or the hot water storage control means 13 issues a stop instruction to the heating control means 26 to stop the heating operation, and the heating control means 26 And the operation of the heating circulation pump 19 is stopped, and the boiling operation is finished.

  Here, the control of the expansion valve 16 during the boiling operation will be described in detail with reference to FIG. 2. When the boiling operation is started in step S1 and the feedback control of the expansion valve 16 is started in step S2, the heating control means is started. 26 detects a temperature difference between the target discharge temperature TD and the discharge temperature detected by the discharge temperature sensor 20 at regular intervals, and the amount of operation of the expansion valve 16 ranges from +4 pls to -4 pls depending on the magnitude of this temperature difference. (Step S3). The positive sign means that the expansion valve 16 is driven in the opening direction, and the negative sign means that the expansion valve 16 is driven in the closing direction, and each numerical value means the absolute amount of operation.

  Next, in step S4, the heating control means 26 determines whether or not the opening of the expansion valve 16 is opened above a certain opening (whether it is closed below a certain opening). Here, with respect to the stepping motor of the expansion valve 16, the current opening degree of the expansion valve 16 is determined by using the value accumulated and stored by the heating control means 26 from the fully open position or the fully closed position. Yes. If it is above a certain opening, it is determined that the boiling load is within the normal range. Therefore, the operation amount of the expansion valve selected in step S3 is determined as it is, and the expansion valve is determined in accordance with this operation amount in step S5. 16 is driven and it returns to step S3 again.

On the other hand, in step S4, if the opening degree of the expansion valve 16 is not opened above a certain opening degree (when it is closed below a certain opening degree), whether any of the following four conditions are satisfied: It is determined whether or not (step S6).
1. Whether the drive frequency of the compressor 14 is equal to or higher than a predetermined high frequency.
2. Whether the discharge pressure detected by the discharge pressure sensor 25 is equal to or higher than a predetermined high pressure.
3. Whether the outside air temperature is lower than a predetermined low temperature (eg, 3 ° C. or lower).
4). Whether the target boiling temperature is equal to or higher than a predetermined high temperature (for example, 85 ° C.).

  If any of the conditions is satisfied in step S6, it is determined that the boiling load is excessive for some reason, and the operation amount of the expansion valve 16 selected in step S3 is limited to −1 pls or more (step S7). ). In step S5, the expansion valve 16 is driven according to the limited operation amount, and the process returns to step S3 again.

  In this way, even in a high load condition where the evaporation capacity of the air heat exchanger 17 is reduced due to snow accumulation or frost formation under a heavy boiling load such as in winter, the expansion valve 16 is moved in the closing direction. Therefore, the increase in torque of the compressor 14 can be slowed down, exceeding the allowable torque of the compressor 14, and the compressor 14 will step out and stop abnormally. Can be prevented.

  Further, since the operation amount in the opening direction of the expansion valve 16 is not limited even under high load conditions, the discharge temperature is quickly returned to the target value even when the discharge temperature exceeds the target value. It is something that can be done.

  If none of the conditions in step S6 is satisfied, it is determined that the boiling load is within the normal range as a whole even if the opening of the expansion valve 16 is closed below a certain level. No in S6, the operation amount of the expansion valve selected in Step S3 is determined as it is, the expansion valve 16 is driven in accordance with this operation amount in Step S5, and the process returns to Step S3 again.

  In a normal load state, the discharge temperature of the refrigerant can be quickly reached the target value by normally controlling the opening degree of the expansion valve, and an efficient operation can be performed.

  The present invention is not limited to the above embodiment, and can be modified without departing from the spirit of the invention. For example, the feed water is heated by a water-refrigerant heat exchanger and passes through a hot water storage tank. The present invention can also be applied to an instantaneous heat pump water heater that directly supplies hot water to a hot water tap. In the above embodiment, the hot water storage tank unit and the heat pump heating means are separated from each other. However, the hot water storage tank unit and the heating control means may also be integrated. It is.

The system diagram of the heat pump type hot water supply apparatus of one Embodiment of this invention. The flowchart for demonstrating the action | operation of the same embodiment.

Explanation of symbols

5 Heat Exchange Water Pipe 6 Heat Exchange Hot Water Pipe 14 Compressor 15 Water Refrigerant Heat Exchanger 16 Expansion Valve 17 Air Heat Exchanger 18 Heat Pump Cycle 20 Discharge Temperature Sensor 22 Outside Air Temperature Sensor 24 Boil Temperature Sensor 25 Discharge Pressure Sensor 26 Heating Control means (control device)

Claims (4)

A heat pump cycle in which a compressor, a water-refrigerant heat exchanger, an expansion valve, and an air heat exchanger are annularly connected; a discharge temperature sensor that detects a refrigerant temperature discharged from the compressor; and a water side of the water-refrigerant heat exchanger A heat exchange water pipe and a heat exchange hot water pipe connected to each other, a boiling temperature sensor for detecting the temperature of hot water provided in the heat exchange hot water pipe and heated by the water refrigerant heat exchanger, and the discharge temperature The operation amount of the valve opening according to the temperature difference between the detected temperature of the sensor and a predetermined target discharge temperature is given to the expansion valve at predetermined intervals to control the opening and closing of the expansion valve, and the boiling temperature sensor A control device for increasing or decreasing the frequency of the compressor so that the detected temperature becomes a desired boiling temperature, the control device is in a state where the opening of the expansion valve is closed below a certain level, and The frequency of the compressor is equal to or higher than a predetermined frequency There the heat pump type hot water supply device being characterized in that limit smaller than normal amount of the operation to the closing direction of the expansion valve at one cycle. A heat pump cycle in which a compressor, a water-refrigerant heat exchanger, an expansion valve, and an air heat exchanger are annularly connected; a discharge temperature sensor that detects a refrigerant temperature discharged from the compressor; and a pressure on a high-pressure side of the heat pump cycle. A discharge pressure sensor to be detected, a heat input water pipe and a heat exchange hot water pipe connected to the water side of the water refrigerant heat exchanger, and provided in the heat exchange hot water pipe are heated by the water refrigerant heat exchanger. A boiling temperature sensor for detecting the temperature of hot water, and an operation amount of a valve opening corresponding to a temperature difference between a detected temperature of the discharge temperature sensor and a predetermined target discharge temperature is given to the expansion valve at predetermined intervals. And a control device that controls the increase and decrease of the frequency of the compressor so that the detected temperature of the boiling temperature sensor becomes a desired boiling temperature. Closed below a certain level A heat pump characterized in that when the discharge pressure detected by the discharge pressure sensor is equal to or higher than a predetermined pressure, an operation amount in the closing direction of the expansion valve in one cycle is limited to be smaller than usual. Water heater. A heat pump cycle in which a compressor, a water-refrigerant heat exchanger, an expansion valve, and an air heat exchanger are annularly connected; a discharge temperature sensor that detects a refrigerant temperature discharged from the compressor; and an outside air temperature sensor that detects an outside air temperature; Detecting the temperature of the hot water supplied to the water side of the water refrigerant heat exchanger and the hot water outlet hot water pipe and the temperature of the hot water provided in the hot water hot water pipe and heated by the water refrigerant heat exchanger A boiling temperature sensor for controlling the opening of the valve, and an opening amount corresponding to a temperature difference between the detected temperature of the discharge temperature sensor and a predetermined target discharge temperature is given to the expansion valve at predetermined intervals to open and close the expansion valve And a control device that increases and decreases the frequency of the compressor so that the detected temperature of the boiling temperature sensor becomes a desired boiling temperature, and the opening of the expansion valve is closed below a certain level And the outside air temperature If the outside temperature detected by the sub is equal to or less than a predetermined outside air temperature, the heat pump type hot water supply device being characterized in that limit smaller than normal amount of the operation to the closing direction of the expansion valve at one cycle. A heat pump cycle in which a compressor, a water-refrigerant heat exchanger, an expansion valve, and an air heat exchanger are annularly connected; a discharge temperature sensor that detects a refrigerant temperature discharged from the compressor; and a water side of the water-refrigerant heat exchanger A heat exchange water pipe and a heat exchange hot water pipe connected to each other, a boiling temperature sensor for detecting the temperature of hot water provided in the heat exchange hot water pipe and heated by the water refrigerant heat exchanger, and the discharge temperature The operation amount of the valve opening according to the temperature difference between the detected temperature of the sensor and a predetermined target discharge temperature is given to the expansion valve at predetermined intervals to control the opening and closing of the expansion valve, and the boiling temperature sensor A controller for increasing or decreasing the frequency of the compressor so that the detected temperature becomes a desired boiling temperature, and when the opening of the expansion valve is closed below a certain level and the boiling temperature is predetermined If it is above the temperature, in one cycle Serial heat pump type hot water supply apparatus is characterized in that limit smaller than normal amount of the operation to the closing direction of the expansion valve.

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