JP2002228276A - Heat pump type water heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat pump type water heater for storing hot water efficiently at a high temperature. SOLUTION: The heat pump type water heater comprises a capacity control section for changing the capacity of a compressor, a flow rate control section for changing the flow rate of a pump, a water supply temperature sensor for detecting the temperature of water at the inlet of a water heat exchanger, and a main control section for fixing the flow rate of the pump for varying the capacity of the compressor when the detection value of a water supply temperature sensor is equal to or less than a specific value, and for fixing the capacity of the compressor and varying the flow rate of the pump when the detection value of the water supply temperature sensor exceeds a specific value when the heat pump type water heater has a refrigeration cycle for condensing a gas refrigerant discharged from a compressor by a first heat exchanger, then evaporating it by a second heat exchanger, sucking the gas refrigerant by the compressor, and performing defrosting operation by a switching valve, and a water circuit for allowing hot water to flow back to a hot water storage bath via a water heat exchanger for exchanging beat with the first heat exchanger by force-feeding water stored in the hot water storage bath using the pump.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention includes a water heat exchanger for exchanging heat with a heat exchanger serving as a condenser. Water stored in a hot water storage tank is converted into hot water through a water heat exchanger by a pump. The present invention relates to a heat pump type water heater for returning to a hot water storage tank.

[0002]

2. Description of the Related Art A conventional heat pump type water heater of this kind is a heat exchange functioning as a condenser by pumping water stored in a hot water tank by a refrigeration cycle having a compressor of variable capacity. A water circuit for returning hot water to a hot water storage tank via a water heat exchanger that performs heat exchange with the vessel.
Thus, when controlling the temperature of the hot water flowing out of the water heat exchanger, that is, the temperature of the hot water, the flow rate of the water or hot water pumped by the pump is fixed, and the compression is performed so that the hot water temperature becomes a predetermined value. Controlling the capabilities of the machine. Then, the compressor and the pump are stopped when the temperature of the water flowing into the water heat exchanger, that is, the supply water temperature reaches a predetermined value.

[0003]

However, in the above-described heat pump water heater, it takes time to increase the capacity of the compressor when the refrigeration cycle is started or when the defrosting operation is canceled. It took a relatively long time to raise the temperature to a predetermined value. For this reason, water or hot water having a temperature equal to or lower than a predetermined temperature flows into the hot water storage tank, and the temperature of the hot water in the hot water storage tank sometimes does not rise to the predetermined temperature.

[0004] Further, since the amount of pressure water supplied by the pump is constant, the set temperature at the time of completion of hot water storage can be increased only to, for example, about 30 ° C, and low-temperature hot water may remain at the bottom of the hot water storage tank. Was. When the remaining hot water is heated by the heater in the hot water storage tank, there is a problem that the overall efficiency as a device is reduced.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a heat pump type hot water supply device capable of storing hot water at high temperature and with high efficiency.

[0006]

According to the first aspect of the present invention,
The gas refrigerant discharged from the compressor is condensed in the first heat exchanger, the condensed liquid refrigerant is evaporated in the second heat exchanger,
A refrigeration cycle in which the evaporated gas refrigerant is sucked into the compressor and the functions of the first and second heat exchangers can be reversed by a switching valve, and water stored in a hot water tank is pumped by a pump. By doing so, it is possible to change the capacity of the compressor in a heat pump water heater having a water circuit for returning hot water to a hot water storage tank via a water heat exchanger that performs heat exchange with the first heat exchanger. A possible capacity control unit, a flow control unit capable of changing the flow rate of the pump, a feedwater temperature sensor for detecting a water temperature at the inlet of the water heat exchanger, and a detection value of the feedwater temperature sensor is equal to or less than a predetermined value. A main control unit that fixes the flow rate of the pump to vary the capacity of the compressor, and when the detection value of the feedwater temperature sensor exceeds a predetermined value, fixes the capacity of the compressor and varies the flow rate of the pump. Which is characterized by having That.

According to a second aspect of the present invention, in the heat pump water heater according to the first aspect, the main control unit stops the operation of the compressor and the pump when the flow rate of the pump becomes maximum. And

[0008] The invention according to claim 3 is the heat pump water heater according to claim 1 or 2, further comprising a tapping temperature sensor for detecting a tapping water temperature at an outlet of the water heat exchanger. At the time of starting the refrigeration cycle or at the time of releasing the defrosting operation, when the detection value of the tapping temperature sensor is equal to or less than a predetermined value,
It is characterized in that the capacity of the compressor is fixed to the maximum and the flow rate of the pump is varied to control the hot water temperature.

According to a fourth aspect of the present invention, in the heat pump water heater according to any one of the first to third aspects,
The capacity control unit is a rotation control unit that can change the rotation speed of the compressor, and the flow control unit is a rotation control unit that can change the rotation speed of the pump.

According to a fifth aspect of the present invention, in the heat pump water heater according to any one of the first to third aspects,
The flow control unit is an opening adjustment valve provided in a piping system of the water circuit.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail based on preferred embodiments shown in the drawings. FIG. 1 is an overall system diagram of a heat pump water heater according to the present invention, and is a refrigeration cycle including a compressor 1, a four-way valve 2, a first heat exchanger 3, an expansion valve 4, and a second heat exchanger 5. And a water circuit including a hot water storage tank 11, a pump 12, a water heat exchanger 13, and an opening adjustment valve 14.

Among them, in the refrigeration cycle, the gas refrigerant discharged from the compressor 1 passes through the four-way valve 2 and is taken into the first heat exchanger along the path indicated by the arrow A, where it is condensed. . The condensed liquid refrigerant is decompressed by the expansion valve 4 along the path shown by the arrow B, and then the second refrigerant generally provided outside the room.
Is vaporized by the heat exchanger 5 and becomes a gaseous refrigerant, and is sucked into the compressor 1 through the four-way valve 2. In this process, when the second heat exchanger 5 is frosted due to the temperature and humidity,
During a certain limited period, the circulation path of the refrigerant is switched by the four-way valve 2 so as to reverse the functions of the first heat exchanger 3 and the second heat exchanger 5, and a known defrosting operation is performed.

On the other hand, in the water circuit, the water stored in the hot water storage tank 11 is led out along the path shown by the arrow C, and is sent to the water heat exchanger 13 by the pump 12. The water heat exchanger 13 exchanges heat with the first heat exchanger 3, and the water sent therein absorbs heat generated when the refrigerant is condensed, and is taken out as hot water. This hot water passes through the opening adjustment valve 14 and is returned to the hot water storage tank 11 along the route shown by the arrow D. Among them, the opening adjustment valve 14 changes the flow rate of water pumped by the operation of the pump 12.
In order to adjust the temperature of the hot water returned to the hot water storage tank 11,
A tap water temperature sensor 21 is provided on a path on the outlet side of the opening degree adjustment valve 14, and a feed water temperature sensor 22 is provided on a path on the inlet side of the pump 12.
Is provided.

FIG. 2 is a block diagram showing a configuration of a control device for controlling the temperature of hot water returned to hot water storage tank 11. In the figure, the tap water temperature sensor 21 and the feed water temperature sensor 22
The main control unit 100 is connected to a main control unit 100 composed of a microprocessor and the like. The main control unit 100 further controls a rotation speed control unit 31 that controls the rotation speed of the compressor 1 and a control unit that controls the opening of the opening control valve 14. The opening degree control unit 32 is connected.

Here, when the refrigeration cycle is started or the defrosting operation is canceled, the main control unit 100 outputs the hot water temperature sensor 21.
Is less than or equal to a predetermined value, a command to fix the capacity of the compressor 1 to the maximum and to control the hot water temperature by changing the flow rate of the pump 12 is issued to the rotation speed control unit 31 and the opening control unit 32. Give to. On the other hand, during normal operation, when the detection value of the feedwater temperature sensor 22 is equal to or less than a predetermined value, the capacity of the compressor 1 is varied by fixing the flow rate of the pump 12, and the detection value of the feedwater temperature sensor 22 exceeds the predetermined value. In this case, a command to fix the capacity of the compressor 1 and change the flow rate of the pump 12 is given to the rotation speed control unit 31 and the opening control unit 32.

Hereinafter, the detailed operation of the main control unit 100 will be described. As is well known, when the refrigeration cycle is started or when the defrosting operation is canceled, the temperature rise of the gas refrigerant discharged from the compressor 1 is extremely slow. Therefore, the heat exchange in the water heat exchanger 13 is not sufficient until the gas refrigerant rises,
Hot water temperature will be low. To prevent this,
The rotation speed of the compressor is fixed to, for example, a maximum value or a value close to the maximum value, and the flow rate of the water pumped by the pump 12 is controlled by the opening adjustment valve 14 so that the tap water temperature becomes the target value. Then, when the flow rate of the water reaches a predetermined value, the flow rate is fixed to the current flow rate, and thereafter, the rotation speed of the compressor 1 is controlled.

FIG. 3 shows a main control unit 1 corresponding to these controls.
12 is a flowchart showing a specific processing procedure of the routine 00.
Here, first, when the engine is started in step 101, the rotational speed of the compressor 1 is fixed to a maximum value or a value close to the maximum value in step 102, and then, in step 103, the tapping temperature is set to a predetermined value. The flow rate of water pumped by the pump 12 is controlled. Next, in step 104, it is determined whether or not the flow rate of the water by the pump 12 has reached a predetermined value. Until the flow rate reaches, the flow rate control in step 103 and the determination in step 104 are repeated. And the pump 12
Is determined to have reached a predetermined value, the flow rate is fixed in step 105, and then the rotation speed of the compressor 1 is set in step 106 so that the tap water temperature becomes a predetermined constant value. Execute control. With the above-described processing, it is possible to prevent a drop in the hot water storage temperature at the time of starting or at the time of releasing the defrosting operation.

On the other hand, the temperature of the water heat exchanger 13 rises due to the above control, and therefore the water temperature at the inlet of the water heat exchanger 13 also rises. It becomes the number of rotations. At this time, the process shifts to tapping temperature control based on the flow rate of water by the pump 12, and when the pump flow rate reaches a maximum, the operations of the compressor 1 and the pump 12 are stopped. If hot water is used during this time and water is supplied to the hot water storage tank 11, the temperature on the inlet side of the water heat exchanger 13 decreases. At this time, if the detection value of the feedwater temperature sensor 22 is equal to or less than a predetermined value, the flow rate of water by the pump 12 is fixed and the compressor 1
The process returns to the tapping temperature control based on the number of rotations.

FIG. 4 shows a main controller 1 corresponding to these controls.
12 is a flowchart showing a specific processing procedure of the routine 00.
Here, first, in step 111, the flow rate of the pump 12 is fixed at a predetermined value, and in step 112, the tap water temperature is controlled to a constant value by controlling the rotation speed of the compressor 1. Next, in step 113, it is determined whether or not the temperature at the inlet of the water heat exchanger 13 has exceeded a predetermined value based on the detection value of the feedwater temperature sensor 22, and the processing in steps 111 to 113 is repeated until the temperature has exceeded. Then, when it is determined that the inlet water temperature has exceeded the predetermined value, it is determined in step 114 whether or not the rotation speed of the compressor 1 has become minimum. Repeat step 114,
The process proceeds to step 115 when it is determined that the minimum has been reached. In step 115, the number of revolutions of the compressor 1 is fixed to a minimum, and subsequently, in step 116, the outlet temperature of the water heat exchanger 13 is controlled to be constant by controlling the flow rate of water pumped by the pump 12. Further, in step 117, the pump 1
It is determined whether or not the flow rate of the water pumped by the pump 2 has reached the maximum. If the flow has not reached the maximum, the processing of step 113 and subsequent steps is executed. Stop operation.

By executing the above processing, it is possible to solve the problems of the conventional apparatus in which the temperature of the hot water in the hot water tank cannot be raised to a predetermined temperature or low-temperature hot water remains at the bottom of the hot water tank. it can.

In the conventional heat pump water heater, when the temperature of the inlet to the water heat exchanger 13 reaches a predetermined value, the remaining water is usually boiled by energizing the heater in the hot water tank. However, according to the present embodiment, it is possible to boil only with a heat pump, the overall efficiency as a device is increased, and as a result, electricity costs can be saved.

In the above-described embodiment, the pump 12 that operates at a constant speed is used, and the amount of water pumped by the pump 12 is adjusted by the opening of the opening adjustment valve 14. However, instead of this,
It is also possible to remove the opening adjustment valve 14 and provide a rotation speed control unit capable of changing the rotation speed of the pump 12, so that the main control unit 100 outputs the rotation speed command.

[0023]

As is apparent from the above description, according to the present invention, it is possible to provide a heat pump water heater capable of storing hot water at high temperature and with high efficiency.

[Brief description of the drawings]

FIG. 1 is an overall system diagram of an embodiment of a heat pump water heater according to the present invention.

FIG. 2 is a block diagram showing a configuration of a control device for controlling the temperature of hot water returned to the hot water storage tank of the embodiment shown in FIG.

FIG. 3 is a flowchart showing a specific processing procedure when the main control unit constituting the control device shown in FIG. 2 is started or when the defrosting operation is canceled.

FIG. 4 is a flowchart showing a specific processing procedure during a normal operation of a main control unit constituting the control device shown in FIG. 2;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor 2 Four-way valve 3 1st heat exchanger 4 Expansion valve 5 2nd heat exchanger 11 Hot water storage tank 12 Pump 13 Water heat exchanger 14 Opening adjustment valve 21 Hot water temperature sensor 22 Feed water temperature sensor 31 Rotation speed control Unit 32 Opening control unit 100 Main control unit

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yuji Matsumoto 336 Tatehara, Fuji-shi, Shizuoka Toshiba Carrier Co., Ltd.

Claims (5)

[Claims] A gas refrigerant discharged from a compressor is condensed in a first heat exchanger, a condensed liquid refrigerant is evaporated in a second heat exchanger, and the vaporized gas refrigerant is supplied to the compressor. By pumping the refrigeration cycle capable of reversing the functions of the first and second heat exchangers by the switching valve and the water stored in the hot water storage tank by pumping,
In a heat pump water heater having a water circuit for returning hot water to the hot water storage tank via a water heat exchanger that performs heat exchange with the first heat exchanger, the capacity of the compressor can be changed. A capacity control unit, a flow rate control unit capable of changing the flow rate of the pump, a feedwater temperature sensor for detecting a water temperature at an inlet of the water heat exchanger, and a detection value of the feedwater temperature sensor being equal to or less than a predetermined value. When
Mainly, the capacity of the compressor is varied by fixing the flow rate of the pump, and when the detection value of the feedwater temperature sensor exceeds a predetermined value, the capacity of the compressor is fixed and the flow rate of the pump is varied. A heat pump water heater, comprising: a control unit; 2. The heat pump water heater according to claim 1, wherein the main control unit stops the operation of the compressor and the pump when the flow rate of the pump becomes maximum. 3. A hot water temperature sensor for detecting a hot water temperature at an outlet of the water heat exchanger, wherein the main control unit detects the hot water temperature when the refrigeration cycle is started or the defrosting operation is canceled. The heat pump hot water supply according to claim 1 or 2, wherein when the detected value is equal to or less than a predetermined value, the capacity of the compressor is fixed at a maximum, and the flow rate of the pump is varied to control the hot water temperature. vessel. 4. The capacity control unit is a rotation control unit capable of changing the rotation speed of the compressor, and the flow control unit is a rotation control unit capable of changing the rotation speed of the pump. 4. The method according to claim 1, wherein
The heat pump water heater according to the item. 5. The valve according to claim 1, wherein the flow control unit is an opening adjustment valve provided in a piping system of the water circuit.
The heat pump water heater according to any one of claims 1 to 3.