JPS6218934Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an air conditioner equipped with a heat pump type refrigeration cycle, and particularly with an improved heating cycle.

Air conditioners equipped with a heat pump type refrigeration cycle that can switch between cooling and heating modes are often used.
However, this type of air conditioner has the disadvantage that its heating capacity decreases when the outside air temperature decreases, especially during heating operation.

In order to prevent this drawback, methods have been used to directly heat the circulating refrigerant to maintain heating capacity. For example, a refrigeration cycle as shown in FIG. 1 or 2 is constructed. 1 in the figure is a compressor,
2 is a four-way valve, 3 is an indoor heat exchanger, 4 is a capillary tube,
5 is a liquid tank, 6 is an expansion valve, 7 is a check valve,
8 is an outdoor heat exchanger, 9 is a refrigerant heater, 10a,
10b is a three-way valve. In the case of FIG. 1, the refrigerant heater 9 is connected in parallel with the outdoor heat exchanger 8, and the second
In the case shown in the figure, the refrigerant heater 9 is connected in series with the outdoor heat exchanger 8. In either case, if the outside temperature drops, the refrigerant heater 9 generates heat and heats the refrigerant, increases the pressure of the refrigerant sucked into the compressor 1, and increases the amount of compressed gas. By increasing the condensation pressure in step 3, the amount of heat released is increased, that is, the heating capacity is improved.

However, in the case of Fig. 1, since the outdoor heat exchanger 9 and the outdoor heat exchanger 9 are operated by switching between them using the three-way valves 10a and 10b, during operation of one, refrigerant accumulates in the other, resulting in the so-called refrigerant stagnation phenomenon. It is large and has particularly poor start-up characteristics, so it takes a long time to obtain hot air. In the case of Figure 2,
This is similar to the means shown in Japanese Unexamined Patent Publication No. 11796 and Japanese Utility Model Application Publication No. 53-57361. That is, the outdoor heat exchanger is located downstream of a pressure reducing device such as an expansion valve or a capillary tube, and is similar in that it supplementally provides heat to the refrigerant exiting the outdoor heat exchanger. Therefore, the refrigerant heater 9 is only used as an auxiliary heat source for the outdoor heat exchanger 8, and has the disadvantage that it cannot replenish a sufficient amount of heat.

The present invention has been developed in view of the above circumstances, and its purpose is to provide an air conditioner that has a relatively simple structure but can improve heating cycle characteristics under low outside temperature conditions. This is what I am trying to do.

An embodiment of the present invention will be described below with reference to FIG. In the figure, 11 is a compressor, 12 is a four-way valve, 13
14 is an indoor heat exchanger, 14 is a capillary tube, 15 is a liquid tank, 16 is an expansion valve, and 17 is an outdoor heat exchanger, and these are connected via the refrigerant pipe P in the above numerical order to form a heat pump type refrigeration cycle. Configure. Note that the capillary tube 14, the expansion valve 16, and the pressure reducing device 18 are configured. Expansion valve 16 of this pressure reducing device 18
A bypass pipe 20 having a first on-off valve 19 communicates in parallel with this. Further, a parallel circuit 2 between the outdoor heat exchanger 17 and the four-way valve 12 includes an auxiliary expansion valve 21 which is an auxiliary pressure reducing device and a second on-off valve 22.
3. Refrigerant heaters 25 accommodating heaters 24 are successively connected in series.

Therefore, in order to perform normal cooling operation, the refrigerant is guided in the direction shown by the broken line arrow in the figure. That is, compressor 1
1 - Four-way valve 12 - Refrigerant heater 25 - Second on-off valve 22 - On-off valve 19 of outdoor heat exchanger 17 - Liquid tank 15 - Capillary tube 14 - Indoor heat exchanger 1
The order is 3-four-way valve 12-compressor 11. The heater 24 of the refrigerant heater 25 does not need to generate heat. The refrigerant evaporates in the indoor heat exchanger 13 and takes away latent heat of vaporization from the air-conditioned room to obtain this cooling effect.

To perform heating operation, the four-way valve 12 is switched to direct the refrigerant as shown by the solid arrow in the figure. That is, compressor 11 - four-way valve 12 - indoor heat exchanger 13 - capillary tube 14 - liquid tank 15 - expansion valve 16 - outdoor heat exchanger 17 - second on-off valve 22 - refrigerant heater 2
5-compressor 11; Particularly under conditions where the outside temperature does not drop, the heater 24 does not need to generate heat. The refrigerant releases condensation heat in the indoor heat exchanger 13 to obtain a heating effect in the air-conditioned room.

Next, a case will be described in which the outside temperature drops extremely and the heating cycle described above does not provide a sufficient heating effect. In this case, the first on-off valve 16 is opened, the second on-off valve 22 is closed, and the refrigerant heater 2
The heater 24 of No. 5 is heated. The refrigerant is supplied to the compressor 11-
Four-way valve 12 - indoor heat exchanger 13 - capillary tube 14 -
Liquid tank 15 - First on-off valve 19 - Outdoor heat exchanger 17 - Auxiliary expansion valve 21 - Refrigerant heater 25
- Four-way valve 12 - Compressor 11 will be guided in this order. That is, the refrigerant is guided from the liquid tank 15 to the refrigerant heater 25 along the dashed line arrow in the figure. The refrigerant that has passed through the first on-off valve 19 is adiabatically expanded by the auxiliary expansion valve 21 via the outdoor heat exchanger 17. and refrigerant heater 2
It evaporates at step 5, but at this time enough heat is transferred to heater 2.
It will be given from 4. The outdoor heat exchanger 17 is located upstream of the auxiliary expansion valve 21, and the refrigerant flowing therethrough is a high-pressure liquid refrigerant.
The flow inside the pipe is in a liquid phase, resulting in less pressure loss.
On the other hand, in the conventional type, since the outdoor heat exchanger is located downstream of the expansion valve, the flow in the pipes of the outdoor heat exchanger becomes a gas-liquid two-phase mainly gas phase, resulting in a large pressure loss. Therefore, in the above embodiment, the refrigerant pressure in the refrigerant heater 25 is significantly higher than in the past, which improves the operating efficiency of the compressor 11 and allows the indoor heat exchanger 13 to generate a high amount of heat without being affected by the outside temperature. Heat of condensation will be released.

Fig. 4 shows a Mollier diagram, where the thin line a indicates a conventional heat pump refrigeration cycle without a refrigerant heater, and the broken line b indicates a conventional heat pump refrigeration cycle with a refrigerant heater. It is. That is, heating the refrigerant increases enthalpy and improves heating efficiency. (In order to clarify the increase in enthalpy, both high and low pressures were regulated to be the same. If the conditions were the same, the b line would shift diagonally to the upper right of the a line.) However, the present invention of the c line shown by the solid line The operating characteristics of the refrigeration cycle will be improved the most. Note that since the capillary tube 14 has a very loose constriction amount, it does not appear as a change in the diagram. If the above-mentioned operation is performed even when the heating starts (starting), the heating effect can be quickly obtained.

As explained above, according to the present invention, the first on-off valve is provided in parallel with the pressure reducing device constituting the heat pump type refrigeration cycle, the refrigerant heater is provided between the outdoor heat exchanger and the four-way valve, A parallel circuit including an auxiliary pressure reducing device and a second on-off valve is provided between the refrigerant heater and the outdoor heat exchanger. When the outside temperature drops extremely, the first and second on-off valves are opened and closed to adiabatically expand the refrigerant in the auxiliary pressure reducing device and evaporate it while heating it in the refrigerant heater. By increasing the suction pressure, a certain level of heating capacity can be achieved. Furthermore, the heating start-up characteristics are improved to achieve comfortable air conditioning, and the refrigerant is conducted to the outdoor heat exchanger and the refrigerant heater, thereby preventing the so-called stagnation phenomenon of the refrigerant therein.

[Brief explanation of the drawing]

1 and 2 are different refrigeration cycle configuration diagrams showing a conventional example of the present invention, FIG. 3 is a refrigeration cycle configuration diagram showing an embodiment of the present invention, and FIG. 4 is a Mollier diagram. 18... Pressure reducing device, 19... First on-off valve, 1
7... Outdoor heat exchanger, 12... Four-way valve, 25...
... Refrigerant heater, 23 ... Parallel circuit, 21 ... Auxiliary pressure reducing device (auxiliary expansion valve), 22 ... Second on-off valve.

Claims (1)

[Scope of utility model registration request] A heat pump type refrigeration cycle and a first refrigeration system installed in parallel with the pressure reducing device that constitutes this refrigeration cycle and opened under low outside temperature conditions during heating operation.
a refrigerant heater that is installed between the outdoor heat exchanger and the four-way valve that constitute the refrigeration cycle and heats the refrigerant under low outside temperature conditions during heating operation; A second on-off valve is provided between the outside heat exchanger and opens during normal cooling/heating operation, and closes under low outside temperature conditions during heating operation, and as the second on-off valve closes, the refrigerant 1. An air conditioner characterized by comprising: a parallel circuit of an auxiliary pressure reducing device that performs a pressure reducing action by conducting the air conditioner.