JP2005337550A - Heat pump water heater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat pump water heater wherein the temperature of hot water stored in a hot water storage tank less varies due to the influences of an outside air temperature and the amount of a circulation flow between a water-refrigerant heat exchanger and the hot water storage tank. <P>SOLUTION: The heat pump water heater comprises a boil-up temperature sensor 11 installed on the outlet side of a hot water flow path 5B in the water-refrigerant heat exchanger 5, a tank inlet temperature sensor 12 installed on the inlet side of the hot water storage tank 1, a first control part 13 for controlling a circulation pump 2 in a hot water circuit B so that the temperature detected by the boil-up temperature sensor 11 gets to a target boil-up temperature, and a second control part 14 for determining whether the temperature detected by the tank inlet temperature sensor 12 is the same as the target boil-up temperature or not and for correcting the target boil-up temperature so that the temperature detected by the tank inlet temperature sensor 12 gets to the target boil-up temperature when both temperatures are different. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a heat pump water heater that controls the temperature of boiling water supplied to a hot water storage tank.

  A conventional heat pump type hot water heater is provided with a temperature sensor at the outlet of the hot water flow path side of the water heat exchanger, and a compressor, an expansion valve, and so on, so that the boiling temperature detected by this temperature sensor reaches the target boiling temperature. The water supply pump is controlled to perform a boiling operation (for example, see Patent Document 1).

JP 2002-323258 A (page 5-6, FIGS. 1 to 3)

  In the conventional heat pump water heater described above, heat is generated in the connection pipe between the water heat exchanger and the hot water tank while the boiling water flowing out from the outlet of the water heat exchanger flows into the hot water tank. The temperature of the hot water stored in the hot water storage tank depends on the specifications such as the pipe length, pipe diameter, heat insulating material, etc. between the water heat exchanger and the hot water storage tank, the outside temperature, and the circulation between the water heat exchanger and the hot water storage tank. There was a problem that the temperature of the hot water in the hot water storage tank varied due to the influence of the flow rate.

  The present invention has been made to solve such a problem, and the specifications of the piping between the water heat exchanger and the hot water storage tank, the outside air temperature, the circulation flow rate between the water heat exchanger and the hot water storage tank, and the like. It is an object of the present invention to provide a heat pump type water heater that reduces variations in hot water temperature in a hot water storage tank due to influence.

  The heat pump type hot water heater according to the present invention includes a compressor that compresses a refrigerant to a high temperature, a refrigerant flow path of a water refrigerant heat exchanger, an expansion valve, and an air heat exchanger that are annularly connected by piping and a heat pump cycle. A hot water storage tank for storing hot water, a circulation pump, and a hot water flow path of a water refrigerant heat exchanger are connected in an annular shape by piping, and absorbs heat from high-temperature and high-pressure refrigerant that is repeatedly performed by a heat pump cycle. A hot water circulation circuit for heating the water, a boiling temperature sensor installed on the outlet side of the hot water flow path of the water refrigerant heat exchanger, a tank inlet temperature sensor installed on the inlet side of the hot water storage tank, and a boiling temperature sensor The first control unit that controls at least the circulation pump of the hot water circulation circuit and the detection temperature of the tank inlet temperature sensor and the target boiling temperature are the same so that the detected temperature becomes the target boiling temperature. Or it determines, when the temperature of both are different, so that the detection temperature of the tank inlet temperature sensor is boiling target temperature, in which a second control unit for correcting the temperature boiling that goal.

  According to the present invention, when the detected temperature of the tank inlet temperature sensor is different from the target boiling temperature, the target boiling temperature is corrected so that the detected temperature of the tank inlet temperature sensor becomes the target boiling temperature. Therefore, the length of the pipe between the water heat exchanger and the hot water storage tank, the diameter of the pipe, the heat insulating material, etc., the outside air temperature, the influence of the circulation flow rate between the water heat exchanger and the hot water storage tank, Variations in hot water storage temperature can be reduced.

Embodiment 1 FIG.
Embodiment 1 of the present invention will be described below with reference to FIGS.
FIG. 1 is an overall configuration diagram showing a heat pump type water heater according to Embodiment 1 of the present invention.
The heat pump type hot water heater shown in this figure includes a heat pump cycle A, a hot water circulation circuit B, a first control unit 13 and a second control unit 14. The heat pump cycle A includes a compressor 4, a refrigerant flow path 5 </ b> A of the water refrigerant heat exchanger 5, an expansion valve 6, and an evaporator 7 (air heat exchanger) provided with an outdoor fan 8. The heat pump cycle A is operated in the form of a ring. The operating principle of the heat pump cycle A is that the refrigerant (carbon dioxide) is compressed by the compressor 4 to be high temperature and high pressure, and this refrigerant is passed through the refrigerant flow path 5A of the water refrigerant heat exchanger 5. Then, the heat is dissipated, expanded by the expansion valve 6 and evaporated by the evaporator 7, and this cycle is continuously repeated to use the heat dissipated by the water / refrigerant heat exchanger 5 for heating the water.

  The compressor 4 is driven by a built-in motor, compresses the refrigerant evaporated by the evaporator 7 to a critical pressure or higher under general use conditions, and discharges it to the water refrigerant heat exchanger 5. The water-refrigerant heat exchanger 5 includes a refrigerant flow path 5A through which high-temperature and high-pressure refrigerant discharged from the compressor 4 flows, and a hot-water flow path 5B through which hot water flows. Are opposed to each other as indicated by arrows in the figure. In the heat pump type hot water heater in the present embodiment, the refrigerant flowing through the water refrigerant heat exchanger 5 normally has a pressure higher than the critical pressure, so it does not condense due to heat exchange with water and is always efficient. High heat exchange can be performed. The expansion valve 6 is a device that decompresses and expands the refrigerant flowing from the water-refrigerant heat exchanger 5 according to the valve opening. The refrigerant expanded by the expansion valve 6 exchanges heat with the air blown by the outdoor fan 8 in the evaporator 7, absorbs energy (enthalpy), and flows into the compressor 4.

  In the hot water circulation circuit B described above, a hot water storage tank 1 for storing hot water for hot water supply, a circulation pump 2, and the hot water flow path 5B described above are connected in an annular shape by a hot water pipe 3. In the hot water circulation circuit B, when the circulation pump 2 is driven, the low temperature hot water existing in the lower part of the hot water storage tank 1 is led to the hot water flow path 5B of the water refrigerant heat exchanger 5 through the hot water pipe 3, It is heated by heat radiation from the refrigerant flow path 5 </ b> A of the refrigerant heat exchanger 5 and returned to the upper part of the hot water storage tank 1 via the hot water pipe 3. In addition, the drive pump 2 can change the head by changing the rotation speed, and can change the flow volume of the hot water flowing into the hot water circulation circuit B. In this system, in order to control the boiling temperature, the flow rate of the hot water circulation circuit B is dealt with by changing the rotational speed of the drive pump 2. Therefore, the circulation pump 2 also functions as a control component. The hot water circulation circuit B is provided with a boiling temperature sensor 11 installed on the outlet side of the hot water flow path 5B and a tank inlet temperature sensor 12 installed on the inlet side of the hot water storage tank 1.

When the target boiling temperature Tp is input through the second control unit 14, the first control unit 13 drives the compressor 4, the expansion valve 6, and the outdoor fan 8 in the heat pump cycle A and circulates in the hot water circulation circuit B. The pump 2 is driven. And the circulating pump 2 of the hot water circulation circuit B is controlled so that the detected temperature Two1 of the boiling temperature sensor 11 becomes the target boiling temperature Tp. When the target boiling temperature Tp set by the operation unit (not shown) is input, the second control unit 14 sets the target boiling temperature Tp in the first control unit 13, and the first control unit 13. When it is confirmed that the detected temperature Two1 of the boiling temperature sensor 11 has reached the target boiling temperature Tp, it is determined whether or not the detected temperature Two2 of the tank inlet temperature sensor 12 is different from the target boiling temperature Tp. . When both temperatures are different, that is, when the detected temperature Two2 of the tank inlet temperature sensor 12 is lower than the target boiling temperature Tp, the target boiling temperature Tp is corrected using, for example, the following equation (1). Is set in the first control unit 13 as the boiling target temperature Tp1.
Tp1 = Tp + (Two1-Two2) (1)

  Factors that the detection temperature Two2 of the tank inlet temperature sensor 12 is low include the length of the pipe between the water / refrigerant heat exchanger 5 and the hot water storage tank 1, the specifications of the pipe diameter and the heat insulating material, the outside air temperature, the water / refrigerant heat exchanger 5 and The circulation flow rate between the hot water storage tank 1 and the like. The above-described boiling end is when an operation stop instruction is received by operating the operation unit, or when the devices of the heat pump cycle A, the hot water circulation circuit B, etc. are abnormal.

Next, the operation | movement at the time of correction | amendment of the target boiling temperature in the heat pump type water heater comprised as mentioned above is demonstrated based on the flowchart of FIG.
When the target boiling temperature Tp set by the operation unit (not shown) is input, the second control unit 14 sets the target boiling temperature Tp in the first control unit 13 and the boiling temperature sensor 11. It is checked whether the detected temperature Two1 has reached the target boiling temperature Tp (S1). On the other hand, when the target boiling temperature Tp is set, the first controller 13 drives the compressor 4, the expansion valve 6 and the outdoor fan 8 of the heat pump cycle A, and drives the circulation pump 2 of the hot water circulation circuit B. To do. And the circulating pump 2 of the hot water circulation circuit B is controlled so that the detected temperature Two1 of the boiling temperature sensor 11 becomes the target boiling temperature Tp, and the detected temperature of the boiling temperature sensor 11 is controlled by the control of the circulating pump 2. When Two1 reaches the target boiling temperature Tp, the second control unit 14 is notified of the information.

  When the second controller 14 confirms that the detected temperature Two1 of the boiling temperature sensor 11 matches the target boiling temperature Tp from the information (S1), it reads the detected temperature Two2 of the tank inlet temperature sensor 12, It is determined whether it is different from the target boiling temperature Tp (S2). When the detected temperature Two2 of the tank inlet temperature sensor 12 and the target boiling temperature Tp are the same, it is determined in S7 whether or not an instruction to end the boiling is given, and the detected temperature Two2 of the tank inlet temperature sensor 12 and the target boiling temperature are determined. If the temperature Tp is different, it is determined whether or not an instruction to end boiling is given in S3. When an instruction to end boiling is detected in S3 or S7, this operation is ended without correcting the target boiling temperature Tp.

When there is no instruction to end boiling in S3, the temperature Two2 detected by the tank inlet temperature sensor 12 is subtracted from the temperature Two1 detected by the boiling temperature sensor 11, and the result is added to the target boiling temperature Tp. Then, the correction is made and the calculated value is set as the boiling target temperature Tp1 (S4). Then, it is determined again whether or not there is an instruction to end boiling (S5), and when the instruction to end boiling is detected, the boiling target temperature Tp1 calculated in S4 is not set in the first control unit 13, This operation is terminated. On the other hand, when there is no instruction to end boiling, the boiling target temperature Tp1 is set in the first controller 13 (S6). And it returns to S2 again and repeats the above-mentioned operation | movement until it detects the instruction | indication of a boiling end.
In addition, the 1st control part 13 will set the circulation pump 2 of the hot water circulation circuit B so that detection temperature Two1 of the boiling temperature sensor 11 may reach the boiling target temperature Tp1 when the boiling target temperature Tp1 is set. Control.

  As described above, according to the first embodiment, when the detected temperature Two2 of the tank inlet temperature sensor 12 and the target boiling temperature Tp are different, the detected temperature Two2 of the tank inlet temperature sensor 12 becomes the target boiling temperature Tp. Then, the detected temperature Two2 of the tank inlet temperature sensor 12 is subtracted from the detected temperature Two1 of the boiling temperature sensor 11, and the result is added to the target boiling temperature Tp for correction, and the calculated value is added to the boiling target temperature Tp1. Are set in the first control unit 13 so that the specifications of the pipe length, pipe diameter, heat insulating material, etc. between the water refrigerant heat exchanger 5 and the hot water storage tank 1, the outside temperature, and the water refrigerant heat exchanger 5 are set. Variation in hot water temperature in the hot water storage tank due to the influence of the circulation flow rate between the hot water storage tank 1 and the hot water storage tank 1 is reduced.

Embodiment 2. FIG.
In the first embodiment described above, every time the detected temperature Two2 of the tank inlet temperature sensor 12 and the target boiling temperature Tp are different, the target boiling temperature Tp is corrected using the above equation (1). Is set as the boiling target temperature Tp1 in the first control unit 13 so that the detected temperature Two2 of the tank inlet temperature sensor 12 becomes the target boiling temperature Tp. In addition, since the amount of information communication between the first control unit 13 and the second control unit 14 increases, in the second embodiment, for example, every 30 minutes elapses in the second control unit 14. 1 is configured to determine whether or not the detected temperature Two2 of the tank inlet temperature sensor 12 is different from the target boiling temperature Tp, and the heat pump type water heater in the present embodiment is shown in FIG. It has the same configuration as the first embodiment of facilities.

Next, the operation | movement at the time of correction | amendment of the target boiling temperature in the heat pump type water heater of Embodiment 2 is demonstrated based on the flowchart of FIG.
When the target boiling temperature Tp set by the operation unit (not shown) is input, the second control unit 14 starts time measurement (not shown), and sets the input target boiling temperature Tp. Set in the first control unit 13. Thereafter, when it is confirmed by the control of the first control unit 13 that the detected temperature Two1 of the boiling temperature sensor 11 and the target boiling temperature Tp are the same (S1), it is determined whether or not the measurement time has passed 30 minutes. If it is determined (S2) and the measurement time has not passed 30 minutes, it waits in S2. Then, when the measurement time has passed 30 minutes, the temperature Two2 detected by the tank inlet temperature sensor 12 is read, and it is determined whether or not it is different from the target boiling temperature Tp (S3). The subsequent operations are the same as those in the first embodiment. That is, when the detected temperature Two2 of the tank inlet temperature sensor 12 read after 30 minutes is different from the target boiling temperature Tp, it is determined whether or not the boiling end instruction has been given (S4), and the boiling end instruction is issued. If not, correction is made to the target boiling temperature Tp based on the arithmetic expression shown in S5, and this is set as the boiling target temperature Tp1. Thereafter, it is determined again whether or not there has been an instruction to end boiling (S6). If there is no instruction to end boiling, the target boiling temperature Tp1 is set in the first controller 13 (S7), and again. After 30 minutes have passed since returning to S2, the above-described operation is repeated.
In addition, when the boiling target temperature Tp1 is set, the 1st control part 13 of the hot water circulation circuit B is set so that detection temperature Two1 of the boiling temperature sensor 11 may reach the boiling target temperature Tp1 as described above. The circulation pump 2 is controlled.

  As described above, in the second embodiment, every 30 minutes, it is determined whether the detected temperature Two2 of the tank inlet temperature sensor 12 and the target boiling temperature Tp are different from each other. Then, the target boiling temperature Tp is corrected to obtain the boiling target temperature Tp1, which is set in the first controller 13 and controlled so that the detected temperature Two1 of the boiling temperature sensor 11 becomes the boiling target temperature Tp1. Because of this, in addition to the effect that the dispersion of hot water temperature in the hot water storage tank due to the influence of the specifications such as piping, the outside air temperature, the circulation flow rate between the water refrigerant heat exchanger 5 and the hot water storage tank 1 is reduced, Compared to the first embodiment, the calculation amount of the second control unit 14 is reduced, and the information communication amount between the first control unit 13 and the second control unit 14 is reduced.

It is a whole lineblock diagram showing the heat pump type hot water supply machine concerning Embodiment 1 of the present invention. 4 is a flowchart showing an operation at the time of correcting the target boiling temperature in the heat pump type hot water heater of the first embodiment. 6 is a flowchart showing an operation at the time of correcting the target boiling temperature in the heat pump type hot water heater of the second embodiment.

Explanation of symbols

A heat pump cycle, B hot water circulation circuit, 1 hot water tank, 2 circulation pump,
1 hot water pipe, 4 compressor, 5 water refrigerant heat exchanger, 5A refrigerant flow path, 5B hot water flow path,
6 expansion valve, 7 evaporator, 8 outdoor fan, 9 refrigerant piping, 11 boiling temperature sensor, 12 tank inlet temperature sensor, 13 first control unit, 14 second control unit.

Claims (3)

A heat pump cycle in which a refrigerant is compressed into a high temperature and a high pressure, a refrigerant flow path of a water refrigerant heat exchanger, an expansion valve and an air heat exchanger are connected in an annular shape by piping;
A hot water storage tank for storing hot water for hot water supply, a circulation pump, and a hot water flow path of the water refrigerant heat exchanger are connected in a ring shape to absorb heat from a high temperature and high pressure refrigerant repeatedly performed by the heat pump cycle. A hot water circulation circuit for heating hot water,
A boiling temperature sensor installed on the outlet side of the hot water flow path of the water refrigerant heat exchanger;
A tank inlet temperature sensor installed on the inlet side of the hot water storage tank;
A first control unit that controls at least a circulation pump of the hot water circulation circuit so that a detected temperature of the boiling temperature sensor becomes a target boiling temperature;
It is determined whether the detected temperature of the tank inlet temperature sensor and the target boiling temperature are the same, and when the two temperatures are different, the target temperature is set so that the detected temperature of the tank inlet temperature sensor becomes the target boiling temperature. A heat pump type water heater comprising a second control unit that corrects the boiling temperature.   The second control unit corrects the target boiling temperature by calculating a difference between a detected temperature of the boiling temperature sensor and a detected temperature of the tank inlet temperature sensor, and performs the correction based on the calculated value. The heat pump type water heater according to claim 1. The second control unit determines whether the detected temperature of the tank inlet temperature sensor and the target boiling temperature are the same, and corrects the target boiling temperature when the two temperatures are different from each other at predetermined time intervals. The heat pump type water heater according to claim 1 or 2.

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