JPH044512B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention relates to an air-conditioning/heating water heater, and more specifically, a refrigerant circuit formed by connecting an outdoor heat exchanger, an indoor heat exchanger, a hot water supply side heat exchanger, and a compressor via a switching mechanism. A mixed refrigerant of a high boiling point refrigerant and a low boiling point refrigerant is sealed in the refrigerant, and a means is provided for changing the composition ratio of the circulating refrigerant, so that the composition ratio of the circulating refrigerant in the refrigerant circuit is changed during hot water supply operation, The present invention relates to an air-conditioning/heating water heater in which the composition ratio of a high-boiling point refrigerant in the refrigerant is increased (hereinafter referred to as "high-boiling point refrigerant rich") to increase the hot water supply temperature. (Prior Art) The present applicant proposed this type of air-conditioning/heating water heater (for the refrigerant circuit, see FIG. 2, which is a drawing related to the present invention) in Japanese Patent Application No. 177189/1989. Thus, the air conditioning/heating water heater shown in FIG. 2 controls the state of the refrigerant sucked into the compressor 4 into a wet state and a superheated state by using an electric expansion valve 9 or 10 installed in the liquid pipe 8. By controlling the suction refrigerant to a wet state, the unevaporated liquid refrigerant rich in high boiling point refrigerant remaining in the refrigerant is stored in the gas-liquid separator 12 provided on the inflow side of the compressor 4, and vice versa. By controlling the suction refrigerant to a superheated state, the high boiling point refrigerant rich liquid refrigerant stored in the gas-liquid separator 12 is evaporated and returned to the circulation circuit, thereby separating the high boiling point refrigerant and the low boiling point refrigerant in the circulation refrigerant. The composition ratio with the boiling point refrigerant is changed. In addition, 1 is an outdoor heat exchanger, 2 is an indoor heat exchanger, 3 is a hot water supply side heat exchanger, 7 is a refrigerant circuit switching mechanism consisting of a four-way switching valve, and the dashed line arrow C is a hot water supply side heat exchanger. It shows the cycle. During hot water supply operation, in order to enable high temperature hot water supply, the composition ratio of the circulating refrigerant is adjusted to be rich in high boiling point refrigerant, so that the condensing temperature can be set high at a relatively low high pressure. By the way, in order to radiate a constant amount of heat per unit time in the hot water supply side heat exchanger 3 having a predetermined capacity, the temperature must be higher than a temperature between the condensed refrigerant in the heat exchanger 3 and the stored hot water to be heated. temperature difference is required. Therefore, in general, if the set hot water temperature is increased,
The condensing temperature and therefore the condensing pressure will increase accordingly. Therefore, conventionally, the upper limit value of the set hot water supply temperature is determined by the allowable high pressure (allowable condensing temperature) set for the compressor 4 from the viewpoint of preventing overload operation and the required temperature difference determined by the predetermined amount of heat radiation. It was set with this in mind. In other words, the upper limit value of the set hot water supply temperature is limited to a temperature lower than the allowable condensing temperature by the required temperature difference. (Problems to be Solved by the Invention) By the way, in the above-mentioned air-conditioning/heating water heater, if a mixed refrigerant with a high composition ratio of high boiling point refrigerant is filled in the refrigerant circuit, a high hot water temperature can be obtained at a lower high pressure. However, in other words, the upper limit value of the set hot water supply temperature can be increased, but in this case, on the other hand, there is a drawback that the refrigerating capacity during cooling and heating operations becomes smaller. Therefore, even in the hot water supply side heat exchanger having a predetermined capacity, if the amount of heat radiated per unit time is reduced, the required temperature difference between the condensed refrigerant and the stored hot water required for this heat radiation will be reduced accordingly. This was invented with a focus on reducing the heat exchanger's size, and its purpose is to actively reduce the capacity of the compressor to reduce the amount of heat released by the hot water heat exchanger when the set hot water temperature is increased. However, even if the refrigerant circuit is not particularly filled with a mixed refrigerant having a high composition ratio of high boiling point refrigerants,
Another point is that the hot water supply temperature (the upper limit value of the set hot water supply temperature) can be increased without increasing the condensing pressure higher than in the past. (Means for Solving the Problems) The configuration of the present invention will be explained based on FIGS. 1 and 2. The outdoor heat exchanger 1, the indoor heat exchanger 2
and a mechanism 7 for switching between the hot water supply side heat exchanger 3 and the compressor 4
are connected to form a refrigerant circuit, and a mixed refrigerant of a high boiling point refrigerant and a low boiling point refrigerant is sealed in this refrigerant circuit. Furthermore, the composition ratio of the circulating refrigerant can be changed by changing the valve opening control of the electric expansion valves 9 and 10 installed in the liquid pipe 8. During hot water supply operation, the composition ratio of the circulating refrigerant can be changed to The composition ratio of the high boiling point refrigerant is increased. Furthermore, the compressor 4 is provided with a capacity control means that enables partial capacity operation of the compressor 4, and a switching means 15 that switches the set hot water temperature during hot water supply operation between high and low, and the switching means 15 is set on the high temperature side. A control means is provided which turns on the capacity control means and causes the compressor 4 to operate at a partial capacity when the temperature is changed to the hot water supply temperature. (Function) During hot water supply operation, when the switching means 15 is switched to the high temperature set hot water supply temperature side, the compressor 4 is thereby operated at partial capacity, so that the refrigerating capacity is reduced. The amount of heat released by the hot water supply side heat exchanger is actively reduced. Therefore, the temperature difference between the condensed refrigerant and the stored hot water, which is necessary to radiate this reduced amount of heat radiation, is also reduced compared to the conventional full capacity operation, so the condensation temperature ( The upper limit value of the set hot water supply temperature can be set high without increasing the high pressure (high pressure). (Example) What is shown in FIG. 2 is an air-conditioning/heating water heater that is capable of cooling, heating, hot water supply, and cooling hot water supply operations. That is, the outdoor heat exchanger 1, the indoor heat exchanger 2, the hot water supply side heat exchanger 3, and the compressor 4 are connected to each other by a switching mechanism 7 consisting of two first and second four-way switching valves 5 and 6.
are connected to form a refrigerant circuit. A mixed refrigerant formed by mixing a high boiling point refrigerant R22 and a low boiling point refrigerant R12 is sealed in this refrigerant circuit. Further, first and second electric expansion valves 9, which can arbitrarily control the valve opening degree, are provided in the tube sheath 8 connecting the outdoor heat exchanger 1 and the indoor heat exchanger 2.
On the other hand, a gas-liquid separator 12 is installed in the suction gas pipe 11 of the compressor 4, which is capable of separating and storing unevaporated liquid refrigerant in the suction refrigerant. In addition, 13 is a liquid receiver, and 14 is an accumulator. Thus, by switching the switching mechanism 7, the refrigeration cycle is formed as shown by the solid line arrow A, as shown in B, and the hot water supply operation is formed as shown in the dashed line arrow C. By forming it as shown by the dotted chain arrow D, cooling hot water supply operation can be performed. At the same time, depending on each operation, one of the first and second electric expansion valves 9, 10 is energized as shown in Table 1 to control the valve opening, or is de-energized and opened to The degree of superheating of the refrigerant sucked into the machine 4 is controlled. The four-way switching valves 5 and 6 of the switching mechanism 7 are switched to the solid line side by energization, and the energization state during each operation is as shown in Table 1 above.

[Table] Furthermore, the composition ratio of the circulating mixed refrigerant in the refrigerant circuit can be changed as described below, and during air conditioning operation, the composition ratio of the high boiling point refrigerant in the circulating refrigerant can be changed to a higher or lower value to increase or decrease the refrigerating capacity. At the same time, during hot water supply operation, the composition ratio of the high boiling point refrigerant in the circulating refrigerant is increased to increase the condensation temperature for high pressure, and therefore hot water can be supplied at a high temperature (in this case, refrigeration capacity will decrease). In the following, capacity adjustment during cooling operation will be explained. When increasing the refrigeration capacity, the valve opening degree of the first electric expansion valve 9 is controlled to be as small as possible so that the suction refrigerant becomes wet. In this way, the unevaporated liquid refrigerant rich in high-boiling point refrigerant remaining in the suction refrigerant flowing through the suction gas pipe 11 is separated by the gas-liquid separator 12 and transferred to the separator 1.
It will be stored in 2. As the liquid refrigerant rich in high boiling point refrigerant is stored in the gas-liquid separator 12 in this way, the composition ratio of the high boiling point refrigerant in the circulating refrigerant decreases, in other words,
The capacity increases because the composition ratio of the low boiling point refrigerant increases. Furthermore, when the valve opening degree of the first electric expansion valve 9 is controlled so that the suction refrigerant is in a superheated state, the high boiling point refrigerant-rich liquid refrigerant stored in the gas-liquid separator 12 evaporates into the suction refrigerant. Then, as the refrigerant is discharged from the gas-liquid separator 12, the composition ratio of the high-boiling refrigerant in the circulating refrigerant rises again, and the capacity decreases. On the other hand, during hot water supply or cooling hot water supply operation, the second or first electric expansion valve 10, 9 is controlled so that the suction refrigerant is in a superheated state, similar to when the capacity decreases during the cooling operation. The composition ratio of the high boiling point refrigerant in the circulating refrigerant is increased. In this way, although the refrigerating capacity decreases, the condensing temperature for high pressure increases, and therefore high temperature hot water supply becomes possible. In the air conditioning/heating water heater configured as above,
The compressor 4 is provided with a capacity control means capable of adjusting the capacity in two stages, and a switching means 1 for switching the set hot water supply temperature between high and low.
5 (see Figure 3), and the switching means 15 during hot water supply or cooling hot water supply operation.
A control means is provided which inputs a signal to operate the capacity control means and cause the compressor 1 to operate at a partial capacity. The compressor 4 is a stationary vane type rotary compressor, and the capacity control means is provided as follows. That is, a cylinder (not shown) is provided with an intermediate discharge hole 42 that communicates with the suction side via a bypass passage 41, and an intermediate discharge valve 43 that opens and closes the intermediate discharge hole 42. A three-way solenoid valve 4 that opens and closes the valve 43 by applying high pressure or low pressure gas to the back side of the valve 43.
There are 4. Thus, by cutting off the power to the three-way solenoid valve 44 and applying high pressure to the back surface of the intermediate discharge valve 43, the intermediate discharge hole 42 is closed and full capacity operation is performed. When the three-way solenoid valve 44 is energized to apply low pressure to the back surface of the intermediate discharge valve 43, the valve 43 is opened by the return spring 45, allowing partial capacity operation. Further, the compressor 4 is provided with a high pressure control switch (not shown) for preventing overload operation, and the compressor 4 is stopped when the high pressure reaches a set pressure. Therefore, the upper limit of the condensing temperature is limited to the condensing temperature t _p corresponding to the set pressure. Further, the switching means comprises a switch 15 connected to the input side of a microcomputer to be described later. Furthermore, the control means is achieved by a program built into the microcomputer. Hereinafter, the electric circuit will be briefly explained. On the input side of the microcomputer C, an operation mode selection means 16 for switching the operation mode and the changeover switch 15 are connected, while on the output side of the microcomputer C, the above-mentioned capacitor is connected. The three-way solenoid valve 44, the four-way switching valves 5 and 6, and the electric expansion valves 9 and 10 of the control means are connected. During the hot water supply operation, the hot water supply temperature setting can be switched between high and low as described above, and both the hot water temperature setting on the high temperature side and the setting hot water temperature on the low temperature side are stored in the ROM of the microcomputer.
has been input in advance. Although not shown, the hot water supply side heat exchanger 3
A detection means for detecting the temperature of the stored hot water is provided on the side, and the microcomputer controls the start/stop of the compressor 1 based on the temperature detected by the detection means and the set hot water supply temperature. There is. Next, the hot water supply operation of the above-mentioned air conditioning/heating water heater will be explained. When hot water supply operation is selected by the operation mode selection means 16, the first and second four-way switching valves 5, 6
is switched to form the hot water supply cycle shown in FIG. 2, and at the same time, the first electric expansion valve 9 is controlled to bring the suction refrigerant into a superheated state. As a result, the circulating refrigerant is rich in high boiling point refrigerants (at the time of initial injection).
Therefore, a high condensation temperature can be obtained at a low high pressure. In other words, high-temperature hot water can be obtained throughout. When the changeover switch 15 is switched to the low temperature set water supply temperature t1 side, the energization of the three-way solenoid valve 44 is cut off, and high pressure acts on the back surface of the intermediate discharge valve 43, causing the intermediate discharge hole to 42 is closed and the compressor 4 is operated at full capacity. As a result, as shown in FIG. 4, the amount of heat released in the hot water supply side heat exchanger 3 becomes a large amount of heat Q1 corresponding to the full capacity operation of the compressor 4. In this way, the stored hot water can be quickly heated with a large amount of heat radiation, and this stored hot water reaches the set hot water temperature t on the low-temperature side.
When it reaches 1, the compressor 1 is stopped. On the other hand, when the changeover switch 15 is switched to the set hot water temperature t2 side, which is the high temperature side, the three-way solenoid valve 44
is excited and the intermediate discharge valve 43 is opened,
The compressor 1 is then switched to partial capacity operation. Then, since the capacity of the compressor 1 decreases, the amount of heat released by the hot water supply side heat exchanger 3 also decreases accordingly (amount of heat Q2). Thus,
The temperature difference Δt2 between the condensed refrigerant and the stored hot water required to radiate this amount of heat Q2 per unit time is smaller than the required temperature difference Δt1 when the amount of heat radiated is Q1. Since the required temperature difference is reduced in this manner, the upper limit temperature of the hot water supply temperature t2 set on the high temperature side can be set higher by (t1 - t2) than the set water supply temperature t1 on the low temperature side. In other words, the hot water supply temperature (t1) set on the high temperature side can be set on the high temperature side by (t1 - t2) closer to the upper limit condensing temperature t0 determined by the high pressure control of the compressor 4. Thus, although the hot water supply capacity is reduced, it is possible to supply hot water at a higher temperature than in the past. In this case as well, when the temperature of the stored hot water reaches the set hot water supply temperature t2, the compressor 4 is stopped. In the above embodiment, the control means is configured using a microcomputer, but as shown in FIG. a series circuit of a thermostat 30 operating at 1 and an electromagnetic switch 31 for driving the compressor 4;
While connecting the parallel circuit with the three-way solenoid valve 44, to the low temperature side switching contact b of the switching switch 15,
The thermostat 32, which operates at a low temperature side contact temperature, and the electromagnetic switch 31 may be connected in a series circuit to form a sequence circuit. Further, the means for changing the composition ratio of the circulating refrigerant is not limited to those of the above-described embodiments. Moreover, the compressor 4 is not limited to a rotary compressor, and any type of compressor can be used.
Further, the capacity control means is not limited to the above-mentioned means. (Effects of the Invention) As described above, in the present invention, when high-temperature hot water is being supplied during hot water supply operation, the capacity of the compressor 4 is actively reduced to reduce the amount of heat released by the hot water supply side heat exchanger. Since the temperature is reduced, the set hot water temperature can be set higher without using a mixed refrigerant with a particularly high composition ratio of high boiling point refrigerant sealed in the refrigerant circuit, and the temperature is higher than before. Hot water can be supplied.

[Brief explanation of drawings]

Figures 1 to 4 are explanatory diagrams of one embodiment of the present invention, where Figure 1 is a complaint response diagram, Figure 2 is a refrigerant circuit diagram, Figure 3 is an electric circuit diagram, and Figure 4 is an explanation of operating conditions. 5 are electrical circuit diagrams of other embodiments. 1...Outdoor heat exchanger, 2...Indoor heat exchanger, 3...Hot water supply side heat exchanger, 4...Compressor, 7...
...Switching mechanism, 15...Switching switch.

Claims (1)

[Claims] 1 A refrigerant circuit formed by connecting an outdoor heat exchanger 1, an indoor heat exchanger 2, a hot water supply side heat exchanger 3, and a compressor 4 via a switching mechanism 7 has a high boiling point refrigerant and a low boiling point refrigerant. An air conditioning/heating water heater in which a mixed refrigerant is sealed and the composition ratio of the circulating refrigerant is changed during hot water supply operation to increase the composition ratio of a high boiling point refrigerant in the refrigerant. A capacity control means that enables partial capacity operation of the machine 4 is provided, and a switching means 15 is provided for switching the set hot water supply temperature during hot water supply operation between high and low, and when the switching means 15 is switched to the set hot water temperature on the high temperature side, the above-mentioned An air-conditioning/heating water heater characterized by comprising: a control means for turning on a capacity control means to cause the compressor 4 to operate at a partial capacity.