JP3840456B2 - Heat pump water heater - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a heat pump water heater that can supply hot water using a heat pump refrigeration cycle.
[0002]
[Prior art]
Conventional hot water heaters are equipped with a combustion hot water heater that does not have a hot water tank, burns gas, etc., instantaneously boiles water with its powerful combustion heat, and supplies hot water, and a large capacity hot water tank. There was an electric water heater that used cheap electricity at nighttime and stored a large amount of hot water heated by an electric heater in the hot water tank during the night and used the hot water stored in the hot water tank during the day. And recently, a heat pump type water heater that is said to be more energy efficient than an electric water heater has begun to spread.
[0003]
A heat pump type hot water heater is equipped with a large capacity hot water tank like an electric water heater, using hot electricity at night to boil hot water in the heat pump circuit and store it in the hot water tank. The type used for is common. This heat pump type hot water heater uses a change in the state of the refrigerant as a heat source, so it is several times better in energy efficiency than electric heater heating, and does not combust gas, so it does not emit CO2 and is friendly to the global environment. It has been broken.
[0004]
As such a conventional heat pump type water heater, there is one disclosed in JP-A-9-126547 (Patent Document 1). The heat pump type hot water heater shown in this prior art includes a heat pump circuit composed of a compressor, a condenser, a pressure reducing device, and an evaporator, a large capacity hot water tank, a heat receiver arranged in a heat exchange manner with the condenser, It has a configuration including a boiling circuit composed of a circulation pump that circulates water in the hot water supply tank to the heat receiver.
[0005]
This conventional heat pump type hot water heater uses an inexpensive electric power at night to operate an energy efficient heat pump circuit to store hot water in the hot water supply tank, so that the water in the hot water supply tank is circulated by a circulation pump to receive heat. The heat pump is gradually warmed up to a predetermined hot water temperature, and when the temperature detector detects that the predetermined hot water temperature has been reached, the operation of the heat pump circuit is stopped. During the day, when hot water is used at the terminal used, it is mixed with use water (for example, clean water) with a mixing valve and diluted to an appropriate temperature and supplied. By increasing the temperature of the hot water stored in the hot water tank as much as possible, the amount of water to be diluted is increased, and the amount of hot water taken out from the hot water tank is decreased.
[0006]
Moreover, although the heat pump water heater described in Patent Document 1 is a type of storing hot water using night electricity as in the case of an electric water heater, a set hot water temperature is set by a decrease in the amount of hot water or a decrease in temperature in the hot water tank. If the temperature cannot be obtained, the heat pump circuit is operated to replenish hot water in the hot water supply tank, or in some cases, the reheating operation can be performed by using a heater using an electric heater and the heat pump circuit in combination.
[0007]
[Patent Document 1]
Japanese Patent Laid-Open No. 9-126547 (see FIG. 3)
[0008]
[Problems to be solved by the invention]
However, since the conventional heat pump type hot water heater is a type that stores a large amount of hot water in the hot water tank, it is not used where the efficiency of the heat pump circuit is sufficiently high, and a lot of heat is generated from the surface of the large hot water tank. The energy is wasted and the energy is wasted, which causes a decrease in energy efficiency. And since it has a large-capacity hot water supply tank, a large space is required, and the transportation and installation of the water heater are troublesome.
[0009]
In addition, conventional heat pump water heaters basically use hot water boiled in the heat pump circuit at night in hot water tanks, and use the stored hot water during the day. There was a case.
[0010]
In the heat pump water heater described in Patent Document 1, a heat pump circuit and a heater using an electric heater are used in combination to perform a chasing operation on the water in the hot water tank to avoid a state where hot water cannot be discharged. However, the configuration requires much more energy than usual.
[0011]
An object of the present invention is to provide a heat pump type water heater capable of supplying hot water with as little energy as possible using a heat pump circuit.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, a heat pump type water heater of the present invention is discharged by a plurality of heat pump circuits connected to a compressor, a condenser, a decompression device, and an evaporator, and condensers of the plurality of heat pump circuits. A heat receiver that heats the water with hot heat, a hot water tank that stores the water warmed by the heat receiver, a hot water supply circuit that supplies the water warmed by the heat receiver to the use terminal, and a control of the hot water circuit A hot water supply control unit, and a plurality of heat pump control units for controlling the operation of the heat pump circuit, wherein the hot water supply control unit is configured to supply water that has come out of the heat receiver when one of the heat pump circuits is stopped. Depending on the temperature of the hot water tank, the hot water from the hot water tank is mixed with the water from the heat receiver, and when the hot water temperature in the hot water tank drops, the hot water from the hot water tank is stopped and It is accomplished by a performing control to reduce the hot water flow rate that.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
[0014]
In FIG. 1, a heat pump type hot water heater in an embodiment of the present invention includes a heat pump circuit 1 and 2 constituted by a heat pump type refrigeration cycle, and a hot water supply circuit 3 for heating and supplying water by the heat pump circuit 1 and 2 (a bathtub described later). 19 is not included), and heat pump control units A and B for controlling the heat pump circuits 1 and 2 and a hot water supply control unit C for controlling the hot water supply circuit 3 are housed in one box.
[0015]
The heat pump circuits 1, 2 compress a low-temperature and low-pressure refrigerant and discharge it as a high-temperature and high-pressure refrigerant, a condenser 5 that exchanges heat with the heat receiver 9 and condenses the discharged refrigerant. The decompression device 6 for decompressing the condensed refrigerant and the evaporator 7 for evaporating the decompressed refrigerant by exchanging heat with the outside air are connected by a refrigerant pipe. A fan 7 a is arranged so as to ventilate the outside air to the evaporator 7.
[0016]
The bypass valve 8 is used for defrosting control in which a high-temperature and high-pressure refrigerant discharged from the compressor 4 is caused to flow through the evaporator 7 by opening the valve, and frost adhering to the evaporator 7 is melted.
[0017]
The compressor 4 is controlled from a low speed (for example, 2000 rotations / minute) to a high speed (for example, 8000 rotations / minute) by PWM control, voltage control (for example, PAM control), and rotation speed control combining these. In particular, when hot water is supplied directly from the heat receiver 9, the heat pump controllers A and B operate the compressor 4 at a high speed.
[0018]
Next, a hot water supply circuit 3 that takes in water from the water pipe and supplies hot water to the use side terminal via the heat receiver 9 or circulates water inside as described later to bring it to a predetermined temperature (for example, 42 ° C.). Will be described.
[0019]
The hot water supply circuit 3 includes a pressure reducing check valve 11, a heat receiver 9, a hot water tank 10, a circulation pump 13, a mixing valve 14 that mixes hot water from the hot water tank 10 and hot water from the heat receiver 9, and a mixing valve 14. A mixing valve 15 for mixing hot water and water from the water supply pipe 27 and a flow rate adjusting valve 16 for adjusting the flow rate of hot water are connected by a water pipe.
[0020]
Moreover, the bathtub water circuit is comprised by the heat receiver 9, the pouring solenoid valve 17, and the circulation pump 18 for bathtubs.
[0021]
The water heater of the present embodiment is a system in which the temperature is raised by exchanging heat between the high-temperature refrigerant of the heat pump circuits 1 and 2 and the water introduced from the water supply pipe 27 in the heat receiver 9, and hot water is supplied to the terminal used as it is. Thus, the conventional large hot water supply tank can be dispensed with.
[0022]
Although the heat of condensation sufficient to warm the water cannot be generated until the pressure condition immediately after the start of operation is stabilized, the hot water stored in the hot water supply tank 10 and the water from the heat receiver 9 are short for the rise. The hot water tank 10 can be downsized while maintaining the set temperature by mixing the hot water. When the operation of the heat pump circuits 1 and 2 is stabilized and the hot water at the set temperature is boiled up, the hot water stored in the hot water supply tank 10 is stopped and the hot water is supplied directly.
[0023]
Next, supply of water to the heat pump water heater will be described. The water supplied from the water supply pipe 27 flows into the pressure reducing check valve 11, and one end of the water is diverted to the hot water supply tank 10 through the water supply pipe 27 and the other to the heat receiver 9. The hot water supply to the use terminal is supplied through the mixing valve 14 and the flow rate adjusting valve 16 at a set temperature. The operation of each part will be described below.
[0024]
As described above, the mixing valve 14 supplementarily mixes the hot water in the hot water supply tank 10 to the set temperature when the temperature of the hot water coming out of the heat receiver 9 does not rise sufficiently immediately after the heat pump circuit operation is started. This is a valve for supplying hot water to the terminal used. The mixing valve 14 and the hot water supply tank 10 are connected by a hot water supply pipe 28.
[0025]
When the temperature of the hot water supplied from the mixing valve 14 is higher than the set temperature, the mixing valve 15 reduces the hot water temperature to the set temperature by mixing with the water supplied from the water supply pipe 27. The flow rate adjustment valve 16 is a valve that regulates the flow rate so that the amount of hot water supply does not exceed the planned total amount.
[0026]
Each part includes a water temperature sensor 20, a water heat exchanger outlet water temperature sensor 21 for detecting the temperature of water from the water heat exchanger composed of the condenser 5 and the heat receiver 9, and the hot water in the mixed hot water tank 10 A water temperature sensor 22 that measures the temperature of the outlet water of the water heat exchanger, a tapping temperature sensor 23 that measures the final tapping water temperature, tank temperature sensors 24, 25, and 26 that measure the amount of remaining hot water in the hot water supply tank 10, and refrigeration On the cycle side, an evaporator temperature sensor 7 b that measures the intermediate temperature of the evaporator 7 and a suction temperature sensor 7 c that detects the suction temperature of the compressor 4 are arranged.
[0027]
And other equipment other than the hot water supply circuit 3 including the heat pump circuits 1 and 2 and the hot water supply tank 10 and the bathtub 19 are housed in a box which will be described later.
[0028]
Next, the operation of each unit when the terminal in use is used will be described. When hot water starts from the use terminal, the flow sensor 12 senses the use of the terminal, starts the compressor 4 and starts the operation of the heat pump circuits 1 and 2. At the initial stage of operation, the heat pump circuits 1 and 2 are still in a standing state, and thus the hot water supply operation using the hot water supply tank 10 is performed. The water introduced from the water supply pipe 27 reaches the lower part of the hot water supply tank 10 through the pressure reducing check valve 11 and the water supply pipe 27. In the hot water supply tank 10, water is supplied from the lower part thereof, and hot water stored in the upper part of the hot water supply tank 10 is pushed out to the hot water supply pipe 28 by the water pressure.
[0029]
On the other hand, the water from the water supply pipe 27 is divided into a water circuit that flows to the heat receiver 9 in order to heat the water by the refrigeration cycle. The temperature is detected by a temperature sensor 22 so that the temperature is set by a mixing valve 14 that mixes hot water from the hot water tank 10 and hot water from the heat receiver 9, and is heated from the hot water from the hot water tank 10 and the refrigeration cycle. The amount of water from the heat receiver 9 is adjusted. In the initial stage of operation, since the water passing through the heat receiver 9 is not sufficiently warmed, the amount of hot water from the hot water supply tank 10 is large and the amount of water flowing through the heat receiver 9 is small (mixing operation mode). . Here, in the initial stage of operation, when the amount of water flowing through the heat receiver 9 is reduced, the temperature can be rapidly increased due to a small amount of water.
[0030]
In this mixing operation mode, when the temperature of the hot water at the terminal used is too high (when the temperature is higher than the set value), the mixing valve 15 is opened and the water from the water supply pipe 27 is mixed to adjust the hot water temperature.
[0031]
As the operation continues, the heat pump circuits 1 and 2 begin to stabilize gradually, the temperature of the hot water discharged from the heat receiver 9 also becomes high, and the mixing valve 14 for mixing the hot water from the hot water supply tank 10 and the hot water from the heat receiver 9 is The hot water from the hot water supply tank 10 is gradually narrowed down, and when the hot water temperature from the heat receiver 9 reaches the set temperature, the hot water from the hot water tank 10 is fully closed and the heat received from the heat pump circuits 1 and 2 Only hot water that has passed through the vessel 9 can be supplied to the terminal (instantaneous water heating mode).
[0032]
In order to supply hot water to the terminal at the set temperature at this time, the temperature sensor 22 senses the temperature, and the mixing valve 15 mixes the hot water discharged from the heat receiver 9 and passed through the mixing valve 14 with the bypassed water. Then, the set hot water is supplied to the terminal. In particular, when the temperature of water supplied from the water supply pipe 27 is high, such as in summer, the temperature of hot water output from the heat receiver 9 becomes higher than the set temperature. At this time, the mixing valve 15 is adjusted so as to reach the set temperature, so that water is appropriately mixed and hot water is supplied to the terminal (water mixing mode).
[0033]
When hot water is supplied to the bathtub 19 or hot water is poured, the same operation as described above (mixing operation mode, instantaneous water heater mode, water mixing mode) is performed, and the hot water solenoid valve 17 is opened to fill the bathtub 19 with hot water.
[0034]
The hot water supply mode of the present embodiment is basically the operation when the heat pump circuits 1 and 2 and the hot water supply terminal are used in the hot water supply circuit, but if one of the heat pump circuits stops abnormally, the capacity is lowered. It is also possible that Furthermore, it is conceivable that the preset temperature (for example, 42 ° C.) is not reached due to a decrease in capacity.
[0035]
In this embodiment, even when one of the heat pump circuits is stopped, the operation control of the heat pump water heater that enables the above-described hot water supply mode (mixing operation mode, instantaneous water heater mode, water mixing mode) is shown in FIG. Will be described.
[0036]
Normally, when the terminal is used, the compressors of the heat pump circuits 1 and 2 are operated. However, when one of the heat pump circuits is stopped, the heat exchange performance between the condenser 5 and the heat receiver 9 is deteriorated and the capacity is lowered. Therefore, when the hot water supply terminal is used in a normal operation, the set temperature cannot be satisfied in the normal hot water supply mode (mixing operation mode, instantaneous water heater mode, water mixing mode). Therefore, operation control that satisfies the set temperature is performed by controlling the hot water supply mode in the abnormal mode.
[0037]
First, it is detected from the water heat exchanger outlet water temperature sensor 21 whether the set temperature is satisfied. If the set temperature is satisfied, the hot water in the hot water supply tank 10 is discharged without using it. However, if the set temperature is not satisfied, the hot water supply tank is increased by increasing the rotation speed of the compressor or increasing the opening of the mixing valve 14 so that the set temperature is reached with the mixed water of the hot water in the heat receiver 9 and the hot water tank 10. The flow rate ratio from 10 is increased and the temperature of hot water passing through the mixing valve 14 is adjusted. And it is detected whether it is set temperature with the temperature sensor 22, and if it becomes, it will pour out hot water as it is.
[0038]
However, since the hot water from the hot water supply tank 10 is limited, the hot water temperature is specified from the detection result of the tank temperature sensor 25 among the sensors 24, 25, and 26 that detect the temperature in the hot water supply tank 10, and the tank hot water temperature is When it falls below the specified value, the hot water from the tank stops.
[0039]
Even if the hot water from the hot water supply tank 10 is exhausted, the temperature sensor 22 detects whether or not the set temperature is reached. However, when the set temperature is not reached, control is performed until the set temperature is reached by increasing the number of revolutions of the compressor, or by reducing the mixing valve 15 and the flow rate adjusting valve 16.
[0040]
Further, when one of the heat pump circuits is stopped and then restarted, a normal hot water supply mode (mixing operation mode, instantaneous water heater mode, water mixing mode) based on the detection result of the hydrothermal outlet water temperature sensor 21. I do.
[0041]
In this embodiment, even if one of the heat pump circuits has a problem, the hot water can be supplied by performing control to maintain the set temperature.
[0042]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the heat pump type water heater which can supply hot water only with a heat pump can be provided.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a heat pump type water heater showing an embodiment of the present invention.
FIG. 2 is a control flowchart when one of the heat pump circuits is abnormally stopped.
[Explanation of symbols]
1, 2 ... Heat pump circuit, 3 ... Hot water supply circuit, 4 ... Compressor, 5 ... Condenser, 6 ... Depressurizer, 7 ... Evaporator, 8 ... Two-way valve, 9 ... Heat receiver DESCRIPTION OF SYMBOLS 10 ... Hot water supply tank, 11 ... Pressure-reduction check valve, 12 ... Flow rate sensor, 13, 18 ... Circulation pump, 14, 15 ... Mixing valve, 16 ... Flow rate adjustment valve, 17 ... Hot water electromagnetic Valve, 19 ... Bath, 20 ... Feed water temperature sensor, 21 ... Water heat exchanger outlet water temperature sensor, 22, 23 ... Temperature sensor, 24, 25, 26 ... Tank temperature sensor, 27 ... Feed water pipe, 28 …… Hot water pipe.

Claims (1)

A plurality of heat pump circuits connected with a compressor, a condenser, a decompression device, and an evaporator, a heat receiver that heats water with the heat released by the condensers of the plurality of heat pump circuits, and the heat receiver. A hot water supply tank for storing hot water, a hot water supply circuit for supplying water warmed by the heat receiver to the use terminal, a hot water control unit for controlling the hot water supply circuit, and a plurality for controlling the operation of the heat pump circuit A heat pump control unit,
The hot water supply control unit mixes hot water in the hot water supply tank with water from the heat receiver according to a temperature of water that has come out of the heat receiver when one of the heat pump circuits is stopped. A heat pump type water heater that performs control to reduce the flow rate of hot water discharged from the use terminal by stopping the supply of hot water from the hot water tank when the hot water temperature in the hot water tank decreases.

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