JPS60181552A - Heat-pump hot-water supply machine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to water heaters using heat pumps, in particular to defrosting operation of frost that has grown on the evaporator and acceleration of compressor startup by balancing high and low pressures in the heat pump cycle. be.

Conventional structure and its problems Regarding the conventional defrosting method for the frost that has grown on the evaporator of a heat pump, a four-way valve is provided on the discharge side of the compressor, as used in heat pump air conditioners, to control the flow direction of the refrigerant. The main type of defrosting is a reverse cycle defrosting configuration in which the high-temperature discharge gas is defrosted by flowing directly to the evaporator side where frost has grown. On the other hand, in so-called air conditioners such as freezers, showcases, and heat pump water heaters that do not require switching between cooling and heating cycles, the high-temperature discharged gas flowing from the compressor to the condenser bypasses the condenser to prevent frost growth. A hot waste bypass defrosting configuration is also used in which defrosting is performed by flowing hot waste through a heated evaporator.

Conventionally, problems with this type of defrosting configuration include the cost of the four-way valve, the complexity of the refrigerant circuit due to the use of the four-way valve, and the transfer of pressure from the high pressure side to the low pressure side via the four-way valve. There was a decrease in capacity due to refrigerant gas leak to the side and heat transfer loss from the high temperature discharge refrigerant gas to the low temperature suction refrigerant gas side. In addition, in the case of a hot gas bypass defrosting configuration using a two-way valve, the bypass amount of high-temperature discharged refrigerant gas from the compressor fluctuates depending on the temperature conditions on the condenser side. The effectiveness was reduced and the defrosting time sometimes took longer.

On the other hand, in order to accelerate the startup of the compressor, due to the torque characteristics of the compressor motor, it will not start if there is an unnecessarily high/low pressure difference at the time of startup. Some models are equipped with a timer to prevent the engine from starting, or a pressure equalization pipe is installed between the discharge and suction of the compressor to balance the pressure, but in any case, a configuration dedicated to promoting the start-up of the compressor is provided. was.

Purpose of the Invention The present invention solves the conventional problems as described above.
The object of the present invention is to provide a heat pump water heater that efficiently defrosts the evaporator using the same refrigerant circuit configuration, and easily balances high and low pressures to promote the startup of the compressor.

Structure of the Invention In order to achieve the above object, the structure of the heat pump water heater according to the present invention is such that a two-way valve is provided in parallel to the pressure reducing mechanism on the evaporator inlet side to which the frost amount detection unit is attached, and the condenser and hot water storage tank are connected to each other. A water circulation path is provided with a pump between the two, and the two-way valve is opened and the pump is stopped when the frost amount detection unit is activated. It is also opened for a certain period of time at startup to balance high and low pressure.

As described above, when the heat pump water heater of the present invention detects the growth of frost on the evaporator, the two-way valve to the evaporator opens and the pump stops operating. In addition to the distributed high-temperature refrigerant liquid, the high-temperature discharged refrigerant gas from the compressor flows into the evaporator all at once without dissipating heat in the condenser and liquefying. To accelerate the startup of the compressor, it is possible to balance the pressure between high and low pressure by simply opening the two-way valve for a certain period of time when the compressor is stopped or started, so there is always a pressure difference between high and low pressure when the compressor is started. This allows the compressor to be restarted easily without any problems.

Description of examples Hereinafter, the present invention will be explained in detail using the drawings.

゛ The figure is an overall configuration diagram showing an embodiment in which the evaporator of the heat pump water heater according to the present invention is used as a solar heat collector. In the figure, 1 is a compressor, 2 is a condenser, 3 is a pressure reducing mechanism, 4 is a two-way valve installed in parallel with the pressure reducing mechanism 3, 5 is an evaporator, and 6 is a frost amount detection unit attached to the evaporator 5. , 7 are accumulators, which constitute the refrigerant circuit of the heat pump.

On the other hand, on the hot water circuit side, 8 is a hot water storage tank, and 9 is a hot water storage tank 8.
10 is a water circulation path, 11 is a water supply pipe, and 12 is a hot water supply pipe.

In the single pump water heater of the present invention as described above, by operating the compressor 1 and pump 9 during hot water storage operation, the high temperature refrigerant gas from the compressor 1 heats the circulating water by the pump 9 in the condenser 2. Condenses and liquefies hot water. When the condensed refrigerant liquid is depressurized by the pressure reducing mechanism 3 and flows through the evaporator 5,
After evaporation using solar heat and atmospheric heat as heat sources, a cycle is formed from the accumulator 7 to the compressor 1. As the heat pump operates, the water in the hot water storage tank 8 is circulated between the hot water tank 8 and the condenser 2, thereby being stored as hot water. In the case of hot water supply, hot water is supplied through the water supply pipe 11 below the hot water storage tank 8 and hot water is pushed up to supply hot water to the room through the hot water supply pipe 12.

On the other hand, when the outside temperature is low, if the heat pump continues to operate, frost begins to form and grow on the evaporator 5, and the heat exchange amount of the evaporator 5 decreases due to the insulation effect of the frost layer, causing the heat pump to heat up. Perform defrosting operation as the capacity and coefficient of performance will deteriorate. In other words, when the frost amount detection unit 6 attached to the evaporator 5 is activated, the two-way valve 4 opens and the operation of the pump 9 is stopped. In addition to the cape, the refrigerant gas discharged from the compressor 1 flows into the evaporator 5 all at once without being condensed in the condenser 2, so that frost easily melts and disappears in a short time. When defrosting is completed, the two-way valve 4 is closed and the pump 9 is operated to resume hot water storage operation.

As described above, the defrosting operation according to the present invention is performed by allowing the high-temperature condensed refrigerant liquid and the high-temperature discharge refrigerant gas to flow into the evaporator 5 at the same time. Compared to the cycle defrosting method and the hot gas bypass defrosting method that bypasses a portion of the discharged refrigerant gas, the defrosting effect is greater, so defrosting can be completed in a short time and normal heat pump operation can be started quickly. It is.

On the other hand, after the compressor 1 is stopped, the high and low pressures continue for a while, so in the past, the main method was to wait for the pressure balance between the high and low pressures before restarting, but in the configuration of the present invention, when the compressor 1 is stopped, the Since the two-way valve 4 is opened for a certain period of time, the pressure difference between high and low pressures disappears immediately, and the restart of the compressor 1 is facilitated and balanced.

The two-way valve 4 may be opened for a certain period of time when the compressor 1 is stopped as described above, or may be opened for a certain period of time when the compressor 1 is started, with the same startup promotion effect.

Effect of the invention According to the present invention, the following effects can be obtained.

(1) During defrosting operation, in addition to the high-temperature refrigerant liquid that had been distributed between the condenser and the pressure reducing mechanism, the high-temperature discharged refrigerant gas from the compressor is simultaneously flowed into the evaporator, so the defrosting action is quick. Defrosting operation can be completed in a short time. This increases the proportion of normal heat pump heating and hot water storage operation time, which increases the coefficient of performance over time, resulting in an energy-saving effect.゛＠) During normal operation and defrosting operation, the refrigerant flows in the same direction in the same refrigerant circuit to form a cycle, so there is no refrigerant gas leak or loss of capacity due to heat transfer when using a four-way valve. Furthermore, since there is no part where refrigerant and lubricating oil accumulate, such as in a hot gas bypass path, reliable operation can be achieved.

(3) Since the high and low pressures are always in a balanced state when the compressor is started, it is possible to accelerate the start-up without waiting and obtain normal heat pump operation.
Abnormal load on the compressor motor can be prevented.

[Brief explanation of the drawing]

The figure is an overall configuration diagram showing an embodiment of a heat pump water heater according to the present invention. 1... Compressor, 2... Condenser, 3... Pressure reduction mechanism,
4... Two-way valve, 5... Evaporator, 6... Frost amount detection unit, 8... Hot water storage tank, 9... Pump, 10... Water circulation path.

Claims (1)

[Claims] A two-way valve is provided in parallel to the pressure reducing mechanism on the inlet side of the evaporator to which the frost amount detection section is attached, and a water circulation path with a pump is configured between the condenser and the hot water storage tank. The heat pump water heater is configured to operate by opening the two-way valve and stopping operation of the pump, and at the same time, opening the two-way valve for a certain period of time when the compressor is stopped or started to balance high and low pressures.