JPS62268959A - 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 (a) Field of Industrial Application The present invention relates to a heat pump water heater, and more particularly to a heat pump water heater using a refrigeration cycle.

(-) Conventional technology and problems Traditionally, heat pump water heaters for obtaining high-temperature water were
The one disclosed in Japanese Patent No. 8-48824 is known. In this system, two compressors are connected in series, so the temperature of the refrigerant discharged from the high-pressure A-compressor rises above 9°C, which can lead to deterioration of the refrigerant and the oil contained in the refrigerant.

In addition, because two-stage compression operation is performed regardless of the load-side hot water temperature or ljl'la refrigerant temperature, there is a drawback that the capacity is not fully demonstrated when the load-side hot water temperature or condensed refrigerant temperature is low. Ta.

(c) Means for Solving the Problems The present invention has been made in view of the above-mentioned facts, and it is possible to obtain high-temperature water while suppressing the rise in discharge refrigerant temperature, and to obtain sufficient capacity. The purpose of the heat pump water heater according to the present invention is to enable hot water supply operation to be carried out efficiently and efficiently, and to achieve this purpose, the heat pump water heater according to the present invention uses two pressure machines and adjusts the hot water temperature to a relatively low stage, e.g. ℃
Up to i-1, two units are operated in parallel, including a parallel circuit of the first compressor and second compressor, a heat exchanger for hot water supply, a first pressure reducing device, a gas-liquid separator, a second pressure reducing device, and an outdoor heat source. In order to enable single-stage compression refrigeration cycle operation in which the refrigerant flows through the exchanger and the parallel circuit of both compressors, the two-stage pressure 8 is used when the hot water temperature is relatively high, for example, from over 50'C to about 85°C. The operations include a first compressor, a gas-liquid separator, and a second compressor.
The refrigerant is passed through the pressure reducing device, the outdoor heat exchanger, and the first compression tank in this order, and the second pressure A machine, the hot water supply heat exchanger, and the first
The load cylinder [
When the hot water temperature or condensed refrigerant temperature on the load side is low, the cycle is switched to a single-stage compression refrigeration cycle, and when the load-side hot water temperature or condensed refrigerant temperature is high, the cycle is switched to a two-stage compression refrigeration cycle.

(D) Examples Examples of the heat pump water heater according to the present invention will be described below with reference to the drawings.

FIG. 1 shows the flow of refrigerant in the single-stage compression refrigeration cycle when the water temperature in the hot water storage tank 5 is relatively low in the hot water supply mode. The high-temperature, high-pressure refrigerant in the first compressor 1 and the second pressure unit 2 passes through the three-way valve 7 and the four-way valve 9, and is condensed in the hot water supply heat exchanger 11 in the hot water storage tank 5. Increase temperature.

The liquid refrigerant that has exited the hot water supply heat exchanger 11 is transferred to a four-way valve 10, a four-way valve 9, a bypass solenoid valve 14 for the outdoor side 1 exchanger B, a first pressure reducing device, that is, an expansion valve 16, a gas-liquid separator 6, and a second It passes through the pressure reducing device, that is, the W tension valve 12, and is evaporated in the outdoor side 1 heat exchanger 4.
and returns to the second compressors 1 and 2.

FIG. 2 shows the flow of refrigerant in the two-stage compression refrigeration cycle when the water temperature in the hot water storage tank 5 is relatively high in the hot water supply mode. The first compressor 1 is on the low stage side, and the second compressor 2 is on the high stage side. The flow of refrigerant is roughly divided into a low-stage cycle and a high-stage cycle.

First, the low stage cycle will be explained. The refrigerant gas discharged from the first compression plant 1 enters the gas-liquid separator 6 through the three-way valve 7, and is condensed and liquefied by the latent heat of evaporation of the liquid refrigerant entering the gas-liquid separator 6 from the higher stage cycle. The condensed and liquefied refrigerant passes through the second pressure reducing device, that is, the expansion valve 12, is evaporated in the outdoor heat exchanger 4, and returns to the first compressor 1 through the four-way valve 10.

Next, the high stage side cycle will be explained. The refrigerant gas discharged from the second compressor 2 passes through the four-way valve 9 and is condensed in the hot water supply heat exchanger 11 in the hot water tank 5, causing the hot water in the hot water tank 5 to rise. The liquid refrigerant leaving the hot water supply heat exchanger 11 enters the gas-liquid separator 6 through the four-way valve 10.9, the bypass solenoid valve 14 of the indoor J heat exchanger 6, and the first pressure reducing device, that is, the expansion valve 16. Gas-liquid separator 6
The liquid refrigerant that has entered the chamber is evaporated by high-temperature gas that has entered the gas-liquid separator 6 from the lower stage cycle. The gas separated in the gas-liquid separator 6 returns to the second compression tank 2.

The heat pump water heater shown in FIG. 1 and the second factor can be applied not only to the hot water supply mode but also to the cooling + hot water supply or heating mode.

FIG. 6 shows the flow of refrigerant in the refrigeration cycle in the case of air conditioning or cooler hot water supply. First compression! The high-temperature, high-pressure gas refrigerant of the first and second compressors 2 passes through the three-way switching valve 7 and the four-way valve 9 to the hot water supply heat exchanger 11 installed in the hot water storage tank 5, and the temperature of the hot water in the hot water storage tank 5 increases. If it is low, the refrigerant now condenses and warms up. The refrigerant in the condensed rice that has exited the hot water supply heat exchanger 11 is condensed in the outdoor heat exchanger 4. The refrigerant exiting the outdoor heat exchanger 4 passes through the second pressure reducing device, ie, the expansion valve 12, and enters the gas-liquid separator 6. The liquid refrigerant that has exited the gas-liquid separator 6 passes through the first pressure reducing device, that is, the expansion valve 16, evaporates in the indoor heat exchanger 6, cools the room, and returns to the first and second compressors. In this case, one or two of the WJ1 compressor 1 and the second compressor 2 can be operated depending on the cooling load.

FIG. 4 shows the flow of refrigerant in the refrigeration cycle for heating. The high-temperature, high-pressure refrigerant in the first kingship machine 1 and the second compressor 2 passes through the three-way valve 7 and the four-way valve 9, and is condensed in the indoor heat exchanger 6 to heat the room. The liquid refrigerant condensed in the indoor heat exchanger 6 passes through the expansion valve 16, the gas-liquid separator 6, the second pressure reducing device, or expansion valve 12, evaporates in the outdoor heat exchanger 4, and returns to the compressor.

Next, the characteristics of the two-stage compression refrigeration cycle operation as shown in FIG. 2 will be described.

Figures 5 and 6 show the ability and CO for changes in intermediate temperature in the two-stage compression and two-stage expansion method using Freon 12.
These graphs are an example of calculating the P/discharge ratio, where the intermediate temperature is the saturation temperature of the refrigerant in the gas-liquid separator, Figure 5 shows the condensation temperature when it is relatively low at 46°C, and Figure 6 shows the condensation temperature. temperature is 9
This is an example of a relatively high temperature of 0°C. The capacity ratio shown is the condensation (or evaporation) when two compressors are connected in parallel and single-stage compression is performed.
It refers to the capacity when two-stage compression is applied to the capacity.

First, when two-stage compression is performed when the condensed refrigerant @ degree (or hot water temperature) is low, the cop (coefficient of performance of the refrigeration cycle) increases somewhat (max. 1.
1) However, the capacity ratio is lower than the total discharge ratio,
The advantages of two-stage compression are not being utilized.

On the other hand, when two-stage compression is performed when the condensed refrigerant temperature (or hot water temperature) is high, the coefficient of performance COP is high and the capacity ratio exceeds the total discharge ratio, as shown in Figure 6. The advantages of stage compression are utilized.

Furthermore, when compressors are connected in series, the discharge refrigerant temperature i increases as shown by the broken line in FIG. 6, but in the two-stage compression according to the present invention, the discharge refrigerant temperature can also be kept low. As is clear from Fig. 6, the coefficient of performance COP shows the highest value when the total discharge ratio is 1.5 to 1.7, that is, the capacity ratio of the two compressors is 1:0.5 to 0.7. However, in practice, if the capacity ratio of the two compressors is 1:0.3 to 0.9, the advantages of two-stage compression can be fully utilized.

(e) Effects of the invention Since the heat pump water heater according to the invention is configured as described above, when performing two-stage compression when the condensed refrigerant temperature is high, the COP is high and the capacity-ratio exceeds the total discharge ratio. By taking advantage of the advantages of two-stage compression, high-temperature water can be obtained while suppressing a rise in discharged refrigerant temperature.

[Brief explanation of the drawing]

Figures 1 to 4 are explanatory diagrams showing the circuit configuration for each mode of operation of an embodiment of the heat pump water heater according to the present invention. Figure 1 shows the hot water supply mode when the water temperature in the tank is low. , Figure 2 shows the hot water supply mode when the water temperature in the tank is high, Figure 6 shows the cooling + hot water supply mode, Figure 4 shows the heating mode, and Figures 5 and 6 show the hot water supply mode. Figure 5 is a graph of capacity, COP, and discharge rate ratio with respect to changes in intermediate temperature in a two-pronged compression two-stage expansion method using Freon 12, and Figure 5 is for heating and hot water supply (46°) modes, and Figure 6 is for Shown is hot water supply (90°) mode. 1... 1st compressor (low stage side at 2nd stage) 2...
2nd compressor (high stage at 2nd stage) 6...Indoor heat exchanger F
! 8 units 4 ... Outdoor heat exchanger 5 ... Hot water storage tank 6 ... Gas-liquid separator 7.8 ... Three-way valve 9.10 ... Four-way valve 11 ... Heat exchanger for hot water supply 12... Second pressure reducing device & tachi expansion valve 16...
- The first pressure reducing device, that is, the expansion valve 14 ... Solenoid valve for bypass Fig. 1 Fig. 2 Fig. 3 Fig. 4 Fig. 5 Fig. 6

Claims (1)

[Claims] A parallel circuit of the first compressor and the second compressor, a heat exchanger for hot water supply,
a single-stage compression refrigeration cycle in which a refrigerant is passed through a first pressure reduction device, a gas-liquid separator, a second pressure reduction device, an outdoor heat exchanger, and a parallel circuit of both compressors; a first compressor; a gas-liquid separator; Second
The refrigerant is passed in the order of the pressure reduction device, the outdoor heat exchanger, and the first compressor, and the refrigerant is made to flow in the order of the second compressor, the hot water supply heat exchanger, the first pressure reduction device, the gas-liquid separator, and the second compressor. Equipped with a two-stage compression refrigeration cycle that can be switched freely, switching to the single-stage compression refrigeration cycle when the load-side water temperature or condensed refrigerant temperature is low, and switching to the two-stage compression refrigeration cycle when the load-side water temperature or condensed refrigerant temperature is high. A heat pump water heater that features switching.