JP2002115922A - Heat pump type hot water heater apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the cost by abolishing a fresh air temperature sensor. SOLUTION: An ECU 3 judges that piping temperature approximates to fresh air temperature to determine the object number of a compressor 4 upon starting the system, based upon the detection temperature A of the temperature sensor 12 or the detection temperature B of the temperature sensor 13, when detection temperatures A, B by temperature sensors 12, 13 mounted on an inlet side and an outlet side of an air refrigerant heat exchanger 7 are inputted, and both detection temperatures substantially approximate to each other. Consequently, an exclusive fresh air temperature sensor for detecting fresh air temperature is abolished, and further there is eliminated the need of parts of a sensor case and the like installed when use is made of a fresh air temperature sensor, so that the cost is reduced. Further, a hot water heater system 1 is adapted such that load variations (variations of the fresh air temperature) during operation by executing ordinary operation in a midnight power time zone, and hence even when the compressor 4 is operated at a predetermined operation in the object number of revolutions set upon the starting of the system, the successive operation is ensured with high efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat pump type hot water supply apparatus which varies the rotation speed of a compressor via an inverter.

[0002]

2. Description of the Related Art In recent years, an inverter system has become the mainstream as a drive system of a heat pump type hot water supply system from the viewpoint of power saving. In this inverter system, the number of revolutions of the compressor is varied by an inverter based on a heat load such as an outside air temperature to control the boiling temperature. The condition for determining the number of rotations of the compressor is generally based on an input signal from an outside air temperature sensor. This is because the load of the heat pump cycle fluctuates greatly depending on the outside air temperature, and in order to always operate the heat pump cycle near the highest cycle efficiency, it is necessary to control the rotation speed of the compressor based on the outside air temperature. It is. The outside air temperature sensor is often arranged on the upstream side of the evaporator in which the outside air flows, in order to detect the original outside temperature while avoiding the influence of solar radiation or the like.

[0003]

However, if the outside air temperature sensor is arranged on the upstream side of the evaporator, the evaporator itself is cooled, so that a value lower than the actual outside air temperature may be detected. For this reason, when the outside air temperature sensor is arranged on the upstream side of the evaporator, it is devised not to detect the radiation temperature of the evaporator (for example,
In order to prevent the influence of the evaporator temperature, it is necessary to surround the outside air temperature sensor with a separate sensor case or the like), which causes an increase in cost. The present invention has been made based on the above circumstances, and its purpose is to eliminate the outside air temperature sensor by using a physical quantity that correlates to the outside air temperature when determining the number of revolutions of the compressor. The idea is to go down.

[0004]

According to a first aspect of the present invention, a control device for controlling the number of revolutions of a compressor is configured to detect an outside air temperature from a temperature detected by a temperature sensor for detecting a pipe temperature of a refrigerant circuit when a heat pump cycle is started. And a target rotational speed of the compressor is determined based on the estimated outside air temperature. In a state where the heat pump cycle is stopped, the pipe temperature of the refrigerant circuit approximates the outside air temperature, so that the outside air temperature can be estimated from the pipe temperature.

[0005] (Means of claim 2) In the heat pump type hot water supply apparatus according to claim 1, the control device inputs the pipe temperature of the inlet side and the outlet side of the air-refrigerant heat exchanger, and both pipe temperatures are substantially equal. At the same time, the target rotational speed of the compressor is determined by regarding the pipe temperature as the outside air temperature. If there is a sufficient stoppage time (for example, 30 minutes or more) before starting the heat pump cycle, the pipe temperatures on the inlet side and the outlet side of the air-refrigerant heat exchanger become substantially equal and approximate to the outside air temperature. Therefore, when the inlet and outlet pipe temperatures of the air-refrigerant heat exchanger are substantially equal, the pipe temperature can be regarded as the outside air temperature.

A control device for controlling the number of revolutions of the compressor measures an elapsed time since the last stop of the operation, and when the heat pump cycle is started, the measured elapsed time exceeds a predetermined time. At this time, the temperature detected by the temperature sensor is regarded as the outside air temperature, and the target rotation speed of the compressor is determined based on the temperature detected by the temperature sensor. If there is a sufficient stoppage time (for example, 30 minutes or more) before starting the heat pump cycle, the piping temperature of the refrigerant circuit approximates the outside air temperature. Can be considered.

According to a fourth aspect of the present invention, in the heat pump type hot water supply apparatus according to the third aspect, the control device regards a pipe temperature on the inlet side or the outlet side of the air-refrigerant heat exchanger as the outside air temperature. Among the refrigerant pipes connecting the refrigerant circuits, it can be said that the pipe temperature on the inlet side or the outlet side of the air-refrigerant heat exchanger exposed to the outside air is closest to the outside air temperature.

(Means of Claim 5) In the heat pump type hot water supply apparatus according to claim 3 or 4, the control device comprises:
If the elapsed time has not reached the predetermined time, the target rotation speed of the compressor is determined based on the outside air temperature during the previous operation. If a sufficient stop time (for example, 30 minutes or more) has not elapsed since the last heat pump cycle was stopped, the pipe temperature is deviated from the outside air temperature, so the pipe temperature cannot be regarded as the outside air temperature. . Therefore, in this case, the target rotation speed of the compressor is determined based on the outside air temperature input during the previous operation.

(6) A control device for controlling the number of revolutions of the compressor based on a value detected by a water temperature sensor for detecting a temperature of water supplied to the tank when the heat pump cycle is started. Is determined. Since the temperature of the water supplied to the tank (water supply temperature) fluctuates in correlation with the outside air temperature, use the water supply temperature instead of the outside air temperature as a condition for determining the target rotation speed of the compressor. Can be.

In the heat pump type hot water supply apparatus according to any one of the first to sixth aspects, the control device keeps the compressor running at the target rotation speed determined at the start of the heat pump cycle until the end of the operation. Operate quickly. In the heat pump hot water supply device of the present invention, since the normal operation is performed using the midnight power, the load fluctuation (the fluctuation of the outside air temperature) during the operation is small, and the compressor is set at the target speed set at the time of starting the system. Even if the vehicle is driven at a high speed, it is possible to continue the operation with high efficiency.

[0011]

Next, a heat pump type hot water supply apparatus of the present invention will be described with reference to the drawings. (First Embodiment) FIG. 1 is a schematic diagram showing a configuration of a heat pump type hot water supply apparatus. The heat pump type hot water supply apparatus (referred to as a hot water supply system 1) of the present embodiment stores hot water (heated water) heated by a heat pump cycle described below in a tank 2, and supplies hot water from the tank 2 during use. This is a system for taking out and supplying water to the user, and its operation is controlled by a control device (referred to as ECU3).

In the heat pump cycle, as shown in FIG. 1, components such as a compressor 4, a water refrigerant heat exchanger 5, an expansion valve 6, an air refrigerant heat exchanger 7, and an accumulator 8 are connected by a refrigerant pipe 9. , And constitutes a refrigerant circuit through which the refrigerant circulates. The compressor 4 incorporates an electric motor driven by the inverter 10, and varies the refrigerant discharge amount according to the number of revolutions of the electric motor. Inverter 10 drives compressor 4 (electric motor) based on a control signal (instruction of target rotation speed) output from ECU 3.

The water-refrigerant heat exchanger 5 exchanges heat between the gas refrigerant compressed by the compressor 4 and the hot-water supply water to heat the hot-water supply water. The expansion valve 6 reduces the pressure of the refrigerant cooled by the water-refrigerant heat exchanger 5 according to the valve opening, and is provided so that the valve opening can be adjusted by a stepping motor 6a. The air-refrigerant heat exchanger 7 evaporates the refrigerant decompressed by the expansion valve 6 by heat exchange with the outside air, and receives forced air from the fan 11. The accumulator 8 stores the excess refrigerant during the cycle so as to be able to cope with the load fluctuation of the compressor 4.

Temperature sensors 12 and 13 are attached to the refrigerant pipe 9 on the inlet side (the expansion valve 6 side) and the outlet side (the accumulator 8 side) of the air refrigerant heat exchanger 7, respectively. These two temperature sensors 12 and 13 are used for controlling the expansion valve 6 by the ECU 3 and detecting the frost of the air-refrigerant heat exchanger 7 during normal operation.
In this embodiment, it is also used as an outside air temperature sensor when the system is started. Therefore, the hot water supply system 1 does not include a dedicated outside air temperature sensor for detecting the outside air temperature.

The tank 2 is made of metal (for example, stainless steel) having excellent corrosion resistance and has a heat insulating structure.
4 is connected to the water / refrigerant heat exchanger 5 by a hot water pipe 15. In addition, the hot-water supply water stored in the tank 2 may be directly used in a kitchen or a bath at home, but may be used as a heat source other than for hot-water supply, for example, for floor heating, indoor air conditioning, and the like. . The water pump 14 is provided such that the flow rate can be controlled by, for example, switching the rotation speed of a built-in motor.

The ECU 3 controls electric devices such as the expansion valve 6, the fan 11 and the water pump 14 in addition to the control of the inverter 10. Next, a processing procedure of the ECU 3 for determining the target rotation speed of the compressor 4 at the time of starting the system will be described based on a flowchart shown in FIG. Step10: Detected temperature A from two temperature sensors 12 and 13
Enter B. Step20: The detected temperatures A and B of the two temperature sensors 12 and 13
Compare. In this determination, when both the detected temperatures A and B are substantially equal (A ≒ B), the process proceeds to Step 30, and when both the detected temperatures are significantly different (A ≠ B), the process proceeds to Step 40.

Step 30: When the detected temperatures A and B of the two temperature sensors 12 and 13 are substantially equal, it can be determined that the pipe temperature is close to the outside air temperature, so that the detected temperature A of the temperature sensor 12 or the temperature sensor The detected temperature B of 13 is input as the outside air temperature, and the process proceeds to Step 50. Step40: Detected temperatures A and B of the two temperature sensors 12 and 13
Are different, it can be determined that the hot water supply system 1 has just been stopped.
B cannot be used as the outside air temperature. Therefore,
Enter the outside air temperature used during the previous operation, and proceed to Step 50. Step 50: The target rotation speed of the compressor 4 is determined from the map shown in FIG. 3 based on the input outside air temperature.

(Effects of the First Embodiment) In the hot water supply system 1 of the present embodiment, the outside air is supplied by using the existing temperature sensors 12 and 13 attached to the inlet side and the outlet side of the air-refrigerant heat exchanger 7. The temperature can be estimated, and the target rotation speed of the compressor 4 at the time of starting the system can be determined based on the outside air temperature. As a result, a dedicated outside air temperature sensor for detecting the outside air temperature can be eliminated, and components such as a sensor case installed when using the outside air temperature sensor are not required, so that cost reduction can be realized. In addition, the present hot water supply system 1 performs normal operation during the midnight power hours,
Even if the load fluctuation (fluctuation in outside air temperature) during operation is small and the compressor 4 is operated at a constant speed at the target rotation speed set at the time of starting the system, it is possible to continue the operation with high efficiency.

(Second Embodiment) FIG. 4 is a schematic diagram showing the configuration of the hot water supply system 1. This embodiment is an example of estimating the outside air temperature using other temperature sensors installed in the refrigerant circuit in addition to the two temperature sensors 12 and 13 described in the first embodiment. For example, as shown in FIG. 4, two temperature sensors 16, 17 attached to the refrigerant pipe 9 on the inlet side and the outlet side of the water-refrigerant heat exchanger 5 are also used, and four temperature sensors 12, 13, When the temperatures detected in 16 and 17 are substantially equal, the temperature detected by each temperature sensor can be regarded as the outside air temperature. Note that only one of the temperature sensors 16 and 17 may be used. Further, the present invention is not limited to the temperature sensors 16 and 17 shown in the present embodiment. If another temperature sensor is installed in the refrigerant circuit, that temperature sensor may be used.

(Third Embodiment) FIG. 5 is a flowchart showing a processing procedure of the ECU 3. This embodiment measures the elapsed time from the previous system stop, and when the elapsed time is sufficiently long, the temperature sensors 12 and 13 attached to the inlet side and the outlet side of the air-refrigerant heat exchanger 7. This is an example in which the detected temperature is regarded as the outside air temperature.

The control contents of this embodiment will be described with reference to the flowchart of FIG. Step10: Detected temperature A from two temperature sensors 12 and 13
Enter B. Step20: Measure the elapsed time since the last system stop,
The elapsed time is a preset reference time (for example, 30
Minute) is determined to be longer or shorter. In this determination, if the measured elapsed time is longer than the reference time, proceed to Step 30;
If the measured elapsed time is shorter than the reference time, the process proceeds to Step 40.

Step 30: If the measured elapsed time is longer than the reference time, the pipe temperatures on the inlet and outlet sides of the air-refrigerant heat exchanger 7 become close to the outside air temperature. Alternatively, the detected temperature B of the temperature sensor 13 is input as the outside air temperature, and the process proceeds to Step 50. Step 40: If the measured elapsed time is shorter than the reference time, the piping temperature differs between the inlet side and the outlet side of the air-refrigerant heat exchanger 7 and is not approximated to the outside air temperature. The temperatures A and B cannot be used as the outside air temperature. Therefore, the outside air temperature used in the previous operation is input, and the process proceeds to Step 50. Step 50: The target rotation speed of the compressor 4 is determined from the map (see FIG. 3) shown in the first embodiment based on the input outside air temperature.

In the method of this embodiment, as in the first embodiment, a dedicated outside air temperature sensor for detecting the outside air temperature can be eliminated, and components such as a sensor case installed when the outside air temperature sensor is used. Is also unnecessary, so that cost reduction can be realized. In addition, the hot water supply system 1 performs a normal operation during the midnight power time period, so that load fluctuations (fluctuations in outside air temperature) during operation are small, and the compressor 4 is driven at a constant speed at a target rotation speed set at the time of starting the system. Even when driving, it is possible to continue driving with high efficiency.

(Fourth Embodiment) FIG. 6 is a map for determining the target rotational speed of the compressor 4 from the feed water temperature. In this embodiment,
This is an example in which the target rotation speed of the compressor 4 is determined from the feedwater temperature when the system is started. The “water supply temperature” is the value of the tank 2
This is the temperature of the water (tap water) supplied to the inside, detected by a water temperature sensor (not shown), and input to the ECU 3.
In this case, since the feedwater temperature fluctuates in correlation with the outside air temperature, the target rotation speed of the compressor 4 is determined from the map shown in FIG. 6 based on the feedwater temperature (the value detected by the water temperature sensor) instead of the outside air temperature. You may.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration of a heat pump hot water supply apparatus (first embodiment).

FIG. 2 is a flowchart showing a processing procedure of an ECU (first embodiment).

FIG. 3 is a map for determining a target rotation speed of a compressor from an outside air temperature (first embodiment).

FIG. 4 is a schematic diagram showing a configuration of a heat pump hot water supply apparatus (second embodiment).

FIG. 5 is a flowchart illustrating a processing procedure of an ECU (third embodiment).

FIG. 6 is a map for determining a target rotation speed of a compressor from a supply water temperature (fourth embodiment).

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 hot water supply system (heat pump hot water supply device) 2 tank 3 ECU (control device) 4 compressor 5 water refrigerant heat exchanger 6 expansion valve 7 air refrigerant heat exchanger 9 refrigerant pipe 10 inverter 12 temperature sensor 13 temperature sensor

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Katsuya Tanaka, 1-1-1, Showa-cho, Kariya-shi, Aichi Prefecture Inside Denso Corporation (72) Inventor Shoichi Yamaguchi 1-1-1, Showa-cho, Kariya-shi, Aichi Co., Ltd. Inside DENSO (72) Inventor Tomoaki Kobayakawa 1-3-1 Uchisaiwai-cho, Chiyoda-ku, Tokyo Tokyo Electric Power Co., Inc. (72) Inventor Kazutoshi Kusanari 1-3-1 Uchisaiwai-cho, Chiyoda-ku, Tokyo Tokyo Electric Power Co., Inc. (72) Inventor Michiyuki Saikawa 2-6-1 Nagasaka, Yokosuka City, Kanagawa Prefecture Central Research Institute of Electric Power Company Yokosuka Research Institute

Claims (7)

[Claims] 1. A compressor driven via an inverter, a water-refrigerant heat exchanger for exchanging heat of refrigerant compressed by the compressor with water to be heated, an expansion valve for controlling a pressure in a cycle, and the expansion valve Constitutes a refrigerant circuit having an air refrigerant heat exchanger for exchanging heat of the depressurized refrigerant with the outside air, and releases the heat absorbed by the air refrigerant heat exchanger from the outside air to the heated water in the water refrigerant heat exchanger. A heat pump cycle, a control device that controls the number of revolutions of the compressor via the inverter, and a temperature sensor that detects a pipe temperature of the refrigerant circuit. At the start of the heat pump cycle, estimate the outside air temperature from the temperature detected by the temperature sensor,
A heat pump type hot water supply apparatus, wherein a target rotation speed of the compressor is determined based on the estimated outside air temperature. 2. The heat pump hot water supply apparatus according to claim 1, wherein the control unit inputs a pipe temperature on an inlet side and an outlet side of the air-refrigerant heat exchanger, and when both pipe temperatures are substantially equal, A heat pump type hot water supply apparatus characterized in that a target rotation speed of the compressor is determined by regarding the pipe temperature as an outside air temperature. 3. A compressor driven via an inverter, a water-refrigerant heat exchanger for exchanging heat of refrigerant compressed by the compressor with water to be heated, an expansion valve for controlling a pressure in a cycle, and the expansion valve. Constitutes a refrigerant circuit having an air refrigerant heat exchanger for exchanging heat of the depressurized refrigerant with the outside air, and releases the heat absorbed by the air refrigerant heat exchanger from the outside air to the heated water in the water refrigerant heat exchanger. A heat pump cycle, a control device that controls the number of revolutions of the compressor via the inverter, and a temperature sensor that detects a pipe temperature of the refrigerant circuit. The elapsed time from the stop of the operation is measured, and when the measured elapsed time exceeds a predetermined time at the start of the heat pump cycle, the temperature detected by the temperature sensor is regarded as the outside air temperature. And, a heat pump type hot water supply apparatus characterized by determining a target rotational speed of the compressor based on the detected temperature of the temperature sensor. 4. The heat pump type hot water supply apparatus according to claim 3, wherein the control device regards a pipe temperature on an inlet side or an outlet side of the air refrigerant heat exchanger as an outside air temperature. Water heater. 5. The heat pump hot water supply apparatus according to claim 3, wherein the control device is configured to control the compressor based on an outside air temperature during a previous operation when the elapsed time has not reached a predetermined time. A heat pump water heater that determines a target rotation speed. 6. A compressor driven via an inverter, a water-refrigerant heat exchanger for exchanging heat of refrigerant compressed by the compressor with water to be heated, an expansion valve for controlling a pressure in a cycle, and the expansion valve. Constitutes a refrigerant circuit having an air refrigerant heat exchanger for exchanging heat of the depressurized refrigerant with the outside air, and releases the heat absorbed by the air refrigerant heat exchanger from the outside air to the heated water in the water refrigerant heat exchanger. A heat pump cycle, a control device for controlling the number of revolutions of the compressor via the inverter, a tank for storing the water to be heated heated by the water-refrigerant heat exchanger, and water supplied to the tank. A water temperature sensor for detecting a temperature of the heat pump type water supply device, wherein the control device is configured to control a target of the compressor based on a temperature detected by the water temperature sensor when the heat pump cycle is started. A heat pump hot water supply device for determining the number of revolutions. 7. The heat pump type hot water supply apparatus according to claim 1, wherein the control device operates the compressor at a constant speed until the operation is completed with the target rotation speed determined at the time of starting the heat pump cycle. A heat pump type hot water supply apparatus characterized in that the hot water supply apparatus is provided.