JPH0245101B2 - REIDANBOSOCHI - Google Patents

Description

Detailed Description of the Invention: Industrial Application Field The present invention has a refrigerant heater that heats a high-pressure liquid refrigerant with an auxiliary heat source, and the thermal energy is used for heating from the main heat source obtained by a low-pressure evaporator during heating. This invention relates to a means for controlling the flow rate of refrigerant flowing within a refrigerant heater in a heating and cooling system that increases the heating capacity of a heat pump by adding it to the output.

Conventional configurations and their problems Conventionally, air-source heat pump type air-conditioning and heating systems have been designed to improve heating performance due to lack of heating capacity at low outside temperatures and the rising characteristics of the heating effect at the start of heating operation, for example, as shown in Figure 2. A heating and cooling device having such a refrigerant heater has been proposed. FIG. 3 is a Mollier diagram showing the operation.

In Fig. 2, 1 is an outdoor unit part, 2 and 2' are indoor unit parts, and these units have two refrigerant pipes 3, 4 and 3', respectively.
4'. Outdoor unit part 1
, 5 is a compressor, 6 is a four-way valve, 7 is an outdoor heat exchanger, and 8 is a throttle device. Reference numeral 9 denotes a liquid receiver installed in the system from pipes 4 and 4' to the expansion device 8, which forms a high-pressure refrigerant liquid circuit during heating. A refrigerant circuit 14 is provided which is connected to a discharge refrigerant gas pipe 13 of the compressor 5 via a stop valve 12 in series. 15 and 16 are solenoid valves that are opened when the indoor unit 2 is used, and 15' and 16' are solenoid valves that are opened when the indoor unit 2' is used. The solenoid valves 15 and 15' are connected to the four-way valve 6 through a branch circuit 17, and the solenoid valves 16 and 16' are connected to the liquid receiver 9 through a branch circuit 18, respectively.

Although any auxiliary heat source may be used as the auxiliary heat source provided in the refrigerant heater 11, the conventional example shown in FIG. 2 shows an example using two electric heaters 19 and 19'. Each electric heater is connected in parallel to a power source 20,
Each has a switch 21 and 21'.
Each switch is configured such that the switch 21 is turned on when the indoor unit 2 is in heating operation, and the switch 21' is turned on when the indoor unit 2' is in heating operation.

In the conventional configuration described above, the operation during two-room heating operation will be described with reference to FIG. 3. The high-pressure refrigerant liquid condensed in the indoor heat exchangers 22 and 22' flows into the liquid receiver 9 (point d in FIG. 3) and is branched into two directions.
One side is depressurized by the expansion device 8 and flows into the outdoor heat exchanger 7 (point e in Figure 3), where it absorbs heat from the outside air and vaporizes, is sucked into the compressor 5 (point a in Figure 3), is compressed, and is discharged as high-pressure refrigerant gas. be done. The other refrigerant flows into the refrigerant heater 11 by the refrigerant pump 10 (point f in Figure 3), is heated and vaporized by the electric heaters 19 and 19', passes through the check valve 12, and is discharged from the compressor 5. The mixture is mixed with gas (point c in Figure 3), passes through the four-way valve 6, and is again condensed and liquefied in the indoor heat exchangers 22 and 22'.

As can be seen from the above explanation, G _M ; refrigerant flow rate G _P of the compressor 5; refrigerant flow rate G _C of the refrigerant pump 10; total refrigerant flow rate Q _H flowing through the indoor heat exchangers 22 and 22'; For example, G _C = G _M + G _C , and Q _H is Q _H = G _C (i _c − i _d ) = G _M (i _c − i _d ) + G _P (i _c − i _d ) In other words, the refrigerant heater 11 Heating capacity Q _RH Q _RH = G _P (i _c − i _d ) This increases the heating capacity by an amount of It was used as a means of achieving However, in order to perform single-room heating operation in such a conventional air-conditioning system, either the electric heater 19 or 19' of the refrigerant heater 11 is turned off to reduce the heating amount.
When trying to reduce Q _RH by half, there were the following drawbacks.

The refrigerant flow rate G _P of the refrigerant pump 10 is the required maximum capacity, that is, the refrigerant heating capacity Q _RH when operating two heating rooms.
Electric heater 19,1
It is designed so that the state of the refrigerant exiting the refrigerant heater 11 when both 9' are turned on is in an appropriate superheated gas region. The reason for this is that the refrigerant gas in the path that merges with the discharge gas from the compressor 5 (point c in Figure 2), passes through the four-way valve 6, and the refrigerant pipe 3, and reaches the inlets of the indoor heat exchangers 22 and 22'. This is to maintain the state of superheated gas. If the outlet refrigerant state at the outlet of the refrigerant heater 11 is close to the saturated state, the confluence point with the compressor 5 (point c in Figure 3) will approach the saturated gas region, and the indoor heat exchanger 22 and 22' Before reaching the inlet, the saturation region is reached due to heat dissipation in the path, and a part of the condensed latent heat that should originally be used 100% for heating capacity is lost, leading to a decrease in heating efficiency. .

However, when operating one heating room, electric heater 1
Turning off one of 9 and 19' is essential from the point of view of preventing an abnormal rise in high pressure in the refrigerant circuit due to a reduction in the number of indoor heat exchangers. Therefore, if the refrigerant heating capacity Q _RH is halved, the refrigerant pump 10
If the refrigerant flow rate G _P is the same as when heating two rooms, the refrigerant state at the outlet of the refrigerant heater 11 will enter the saturated region (point g in Figure 3), resulting in the aforementioned drawback of decreasing heating efficiency. It's coming. In order to prevent this, it was necessary to change the flow rate G _P of the refrigerant pump 10 in accordance with the change in the heating amount Q _RH to maintain the refrigerant state at the outlet of the refrigerant heater 11 in a constant superheated gas state. For this reason, it is necessary to provide a flow rate variable means for the refrigerant pump 10. Specifically, there are methods of changing the rotation speed of the refrigerant pump 10 and methods of providing a flow rate adjustment valve at the outlet or inlet side of the refrigerant pump 10, but the former requires an electrical control circuit, and the latter requires a valve. Both of these factors increased cost and complexity, such as the need for moving parts to drive the motor.

Purpose of the Invention The present invention provides a refrigerant gas-liquid separator between the refrigerant heater outlet and the compressor discharge gas pipe, and connects the liquid reservoir of the gas-liquid separator and the refrigerant pump suction side through a throttling resistor. The flow rate of the refrigerant pump is controlled using an inexpensive and simple configuration that includes a connecting bypass circuit, and the heating amount of the refrigerant heater changes from heating 2 rooms to heating 1 room.
It is an object of the present invention to provide a refrigerant flow rate control means that maintains the refrigerant state at the outlet of a refrigerant heater to a saturated gas state at the minimum even if the room temperature changes significantly.

Structure of the Invention To achieve this object, the present invention provides a heat pump heating cycle composed of a high-pressure refrigerant condensing heat exchanger, a low-pressure evaporative heat exchanger, and a compressor.
A refrigerant circuit is provided for guiding the high-pressure liquid refrigerant exiting the high-pressure refrigerant condensing heat exchanger to a compressor discharge refrigerant circuit via a refrigerant pump, a refrigerant heater, and a refrigerant gas-liquid separator,
Furthermore, a bypass circuit is provided that connects the liquid reservoir portion of the refrigerant gas-liquid separator and the suction side of the refrigerant pump via a throttling resistor.

With this configuration, even if the heating amount of the refrigerant heater changes, the state of the refrigerant at the outlet of the refrigerant heater can be maintained at the minimum saturated gas state.

DESCRIPTION OF THE EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. 1 of the accompanying drawings.

In the figure, parts that are the same as those in the conventional example of FIG. 2 are designated by the same numbers. Components different from the conventional example include a refrigerant gas-liquid separator 23 provided between the outlet side of the refrigerant heater 11 and the check valve 12, and a liquid reservoir 24 of the refrigerant gas-liquid separator 23 and the refrigerant pump 10. The main feature is that a bypass circuit 26 is provided which communicates with the suction side via a throttle resistor 25. The aperture resistor 25
is composed of a capillary tube, but any structure may be used as long as the required flow resistance can be obtained.

Next, the operation of the present invention will be explained.

Heating capacity of refrigerant heater 11 when operating two heating rooms
It is assumed that Q _RH is supplied with both the electric heaters 19 and 19' turned on, and the refrigerant state at the outlet of the refrigerant heater 11 maintains an appropriate superheated gas state. Therefore, no liquid refrigerant exists in the refrigerant gas-liquid separator 23. At this time, a part of the refrigerant gas in the refrigerant gas-liquid separator 23 flows into the suction side of the refrigerant pump 10 through the throttle resistor 25 (dashed line arrow). Therefore, not only the high-pressure liquid refrigerant coming from the liquid receiver 9 but also the gas refrigerant coming through the bypass circuit 17 is mixed into the refrigerant pump 10 in the form of bubbles. However, since the inlet of the throttle resistor 25 is a gas refrigerant, its bypass flow path resistance is large, and the bypass flow rate can be reduced, ensuring a sufficient refrigerant flow rate from the refrigerant gas-liquid separator 23 to the compressor. I can do that.

Next, the operation during single room heating operation will be explained.
When heating one room, one indoor unit, for example 2', is stopped, so the electric heater 1 in the refrigerant heater 11
9' is also turned off, and the refrigerant heating capacity _QRH decreases.
At this time, the flow rate of the refrigerant pump 10 hardly decreases because the pump rotation speed is constant.

Therefore, in the heating state at the exit of the refrigerant heater 11, the refrigerant enthalpy decreases and enters the saturated region, and liquid refrigerant begins to accumulate in the refrigerant vapor-liquid separator 23, and the inlet of the throttle resistor 25 There will be liquid refrigerant on the side. As a result, the bypass flow path resistance of the throttle resistor 25 is greatly reduced, increasing the bypass flow rate. If the flow path resistance of the throttle resistor 25 is appropriately selected, the liquid refrigerant in the refrigerant gas-liquid separator 23 is returned to the suction side of the refrigerant pump 10 via the bypass circuit 26, and the gas refrigerant is returned to the compressor 5 in a saturated gas state. can be sent to the confluence point (point c) with the discharged gas.

As a result, the degree of superheating at the confluence point (point c in Figure 1) with the discharged refrigerant gas from the compressor 5 is lower than when heating two rooms, but it is still maintained, and it is passed through the four-way valve 6 and the refrigerant pipe 3 into the room. The state of the refrigerant gas in the path leading to the inlet of the heat exchanger 2 can be maintained in a superheated gas state,
In the path, condensation of the refrigerant due to heat radiation can be prevented, and the latent heat of condensation can be effectively used within the indoor heat exchanger 2, thereby preventing a decrease in heating efficiency.

Effects of the Invention As described above, the present invention branches the high-pressure refrigerant liquid exiting the high-pressure refrigerant condensing heat exchanger in a heat pump heating cycle, and in addition to the refrigerant circuit to the low-pressure evaporative heat exchanger and compressor, A refrigerant circuit is provided that guides high-pressure liquid refrigerant to a compressor discharge refrigerant circuit via a refrigerant pump, a refrigerant heater, and a refrigerant air flow separator, and the liquid reservoir portion of the refrigerant gas-liquid separator and the refrigerant pump suction side are throttled. By using a simple and inexpensive configuration that includes a bypass circuit that communicates through a resistor, the bypass flow rate of the bypass circuit can be adjusted by utilizing changes in the state of the refrigerant at the outlet of the refrigerant heater due to changes in the heating capacity of the refrigerant heater. It is possible to control the flow rate of refrigerant heading to the confluence point with the discharge gas of the compressor. As a result, the state of the refrigerant at the outlet of the refrigerant gas-liquid separator can be maintained at a minimum, almost constant saturated gas state, which prevents refrigerant gas from condensing before the inlet of the indoor heat exchanger and reducing heating efficiency. can be prevented. In the embodiment of the present invention, a two-room air-conditioning system has been described, but even if the present invention is implemented with a single-room air-conditioning system in which each indoor unit has one unit, the same effect can be obtained with respect to changes in refrigerant heating capacity. Needless to say, I have one.

[Brief explanation of drawings]

Fig. 1 is a refrigerant circuit diagram showing an embodiment of the air conditioning system of the present invention, Fig. 2 is a refrigerant circuit diagram of a conventional air conditioning system, and Fig. 3 is a Mollier diagram showing the operation of the air conditioning system shown in Fig. 2. be. 5...Compressor, 7...Outdoor heat exchanger, 10...
Refrigerant pump, 11... Refrigerant heater, 22, 22'
... Indoor heat exchanger, 23 ... Refrigerant gas-liquid separator, 2
5...Aperture resistance, 26...Bypass circuit.

Claims (1)

[Claims] 1. The high-pressure liquid refrigerant that has exited the high-pressure refrigerant condensing heat exchanger is passed through a refrigerant pump, a refrigerant heater, and a refrigerant gas-liquid to a heat pump heating cycle composed of a high-pressure refrigerant condensing heat exchanger, a low-pressure evaporative heat exchanger, and a compressor. A heating and cooling system comprising a refrigerant circuit that leads to a compressor discharge refrigerant circuit via a separator, and a bypass circuit that connects a liquid reservoir portion of the refrigerant gas-liquid separator and the suction side of the refrigerant pump via a throttling resistor. .