JPH062066U - Air conditioner - Google Patents

Abstract

(57) [Summary] [Purpose] Aiming to improve comfort during cooling operation. [Structure] The figure shows the refrigeration cycle of the air conditioner. The refrigerant discharged from the compressor 1 during the cooling operation flows through the four-way valve 2, the outdoor heat exchanger 3, the expansion valve 4, and the indoor heat exchanger 5 in this order, and then passes through the four-way valve 2 again to the accumulator 1a. Enter and return to compressor 1. Reference numeral 6 is a temperature sensor for detecting the temperature of the indoor heat exchanger 5. Depending on the operating conditions during the cooling operation, a supercooled state may occur, and the temperature blown out from the indoor unit may drop too much. In order to eliminate this problem, the heater 7 is provided near the indoor heat exchanger 5 of the refrigerant pipe connecting the expansion valve 4 and the indoor heat exchanger 5 for heating. The indoor unit control unit 8 controls so that the output of the heater 7 decreases as the temperature of the indoor heat exchanger 5 detected by the temperature sensor 6 increases.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to means for preventing overcooling during cooling operation of an air conditioner.

[0002]

[Prior art]

 The refrigeration cycle (refrigerant circuit) of the air conditioner is basically a compressor, a four-way valve, an outdoor heat exchanger, a throttle means (expansion valve), and an indoor heat exchanger, which are connected by piping. When performing cooling operation in an air conditioner equipped with a simple refrigeration cycle, the refrigerant in the freeze-freezing cycle becomes a high-temperature high-pressure gas state on the inlet side of the outdoor heat exchanger and a high-temperature high-pressure liquid state on the outlet side. The rotation speed of the compressor is controlled so that the inlet side of the inner heat exchanger is in a low-temperature and low-pressure liquid state, and the outlet side is in a low-temperature and low-pressure gaseous state, and the expansion valve throttling control is controlled. If the refrigerant returning to the outlet of the indoor heat exchanger, i.e., the compressor, is in a liquid state, the expansion valve should be further throttled to reduce the amount of refrigerant circulation and to allow sufficient vaporization in the indoor heat exchanger. Gasification to eliminate the liquid return to the compressor.

[0003]

[Problems to be solved by the device]

 However, if the compressor is operated at a low frequency at low room temperature and the expansion valve is narrowed down to suppress the amount of refrigerant circulation and prevent the liquid from returning to the compressor, the evaporation temperature becomes too low and There is a problem that the temperature of air blown out from the machine is too low. Also, if the expansion valve is operated without throttling, the amount of heat exchanged by the indoor heat exchanger will decrease, and the dehumidification capacity will decrease, and the liquid return to the compressor will not be eliminated, which will also adversely affect the life of the compressor. It will be. Therefore, it is an object of the present invention to provide an air conditioner that solves these problems.

[0004]

[Means for Solving the Problems]

 The present invention has been made to solve the above-mentioned problems, and is applied to the indoor heat exchanger of a refrigeration cycle including a compressor, a four-way valve, an outdoor heat exchanger, a throttle means, an indoor heat exchanger, etc. A temperature sensor for detecting the temperature of the heat exchanger is provided, and heating means is provided near the indoor heat exchanger of the refrigerant pipe connecting the throttle means and the indoor heat exchanger, and the output of the heating means is provided as described above. Control is performed according to the temperature of the indoor heat exchanger detected by the temperature sensor.

[0005]

[Action]

 With the above configuration, the refrigerant flowing into the indoor heat exchanger can be heated by the heating means provided in the refrigerant pipe in correspondence with the temperature of the indoor heat exchanger detected during the cooling operation. Therefore, it is possible to prevent the indoor heat exchanger from overcooling when the compressor is operated at a low frequency, and to prevent the refrigerant from returning to the compressor in a liquid state.

[0006]

【Example】

 An embodiment of the present invention will be described below with reference to FIGS. Fig. 1 shows a refrigeration cycle of an air conditioner and its control system. 1 is a compressor, 2 is a four-way valve that switches the flow of refrigerant discharged from the compressor 1 in accordance with cooling operation and heating operation, 3 Is an outdoor side heat exchanger, 4 is an expansion valve provided as throttle means for controlling the flow of the refrigerant, and 5 is an indoor side heat exchanger. The indoor heat exchanger 5 is provided with a temperature sensor 6 for detecting the temperature of the heat exchanger 5, and the indoor heat exchange of the refrigerant pipe connecting the indoor heat exchanger 5 and the throttle means 4 is performed. A heater 7 is provided near the container 5 as an overheating means.

Reference numeral 8 denotes an indoor unit control unit, 9 denotes an outdoor unit control unit, which are connected by a signal line and an electric power line, and the indoor unit control unit 8 controls the heater 7 as well as an indoor fan motor not shown. The outdoor unit control unit 9 controls the compressor 1, the four-way valve 2, the expansion valve 4, and an unillustrated outdoor fan motor. Fig. 2 shows the relationship between the temperature of the indoor heat exchanger 5 and the output of the heater 7. When the temperature of the indoor heat exchanger 5 becomes almost 0 ° C during the cooling operation, the output of the heater 7 becomes maximum. Therefore, the output of the heater 7 corresponds to the temperature of the indoor heat exchanger 5 detected by the temperature sensor 6 so that the output of the heater 7 becomes 0 when the temperature of the indoor heat exchanger 5 becomes approximately 10 ° C. It is designed to be controlled.

By the way, the refrigerating capacity (heat exchange amount) Q of the air conditioner (indoor heat exchanger 5) is considered to be the sum of sensible heat and latent heat. The sensible heat content when heated by the heater 7 becomes the heat content and the heat absorption content from the intake air, and the refrigerating capacity Q at that time corresponds to the sum of the heat absorption content and the latent heat content from the heat content and the intake air. Looking at this with respect to the intake air, the refrigeration capacity Q = heating amount + (heat absorption amount from the intake air + latent heat amount), and assuming that the overall sensible heat ratio is the same, the heated one becomes the intake air. The sensible heat ratio becomes smaller. In other words, by heating the refrigerant, it can be said that the temperature of air blown out from the indoor unit becomes higher even with the same cooling capacity (same dehumidifying capacity). Further, since the vaporization of the refrigerant is promoted by heating the refrigerant flowing into the indoor heat exchanger 5, the expansion / contraction of the expansion valve 4 tends to be loosened, and the reduction in the circulation amount of the refrigerant in the refrigeration cycle is prevented. You will be able to FIG. 3 is a Mollier diagram showing the difference between the case where the heater 7 is used (broken line) and the case where it is not used (solid line). The pressure P is slightly higher when the heater 7 is used.

[0009]

[Effect of device]

 In the case of an air conditioner equipped with a heater as described above, the refrigerant that returns to the compressor does not remain in a liquid state, which eliminates the possibility of adversely affecting the compressor. The blown air does not get too cold, so comfortable air conditioning is possible.

[Brief description of drawings]

FIG. 1 is a block diagram showing a refrigeration cycle and a control system thereof according to the present invention.

FIG. 2 is an explanatory view showing an example of controlling a heater according to the present invention.

FIG. 3 is a Mollier diagram showing the results of implementation of the present invention.

[Explanation of symbols]

 1 Compressor 1a Accumulator 2 Four-way valve 3 Outdoor heat exchanger 4 Expansion valve (throttle means) 5 Indoor heat exchanger 6 Temperature sensor 7 Heater (heating means) 8 Indoor unit control unit 9 Outdoor unit control unit

Claims (1)

[Scope of utility model registration request] 1. A temperature sensor for detecting the temperature of the heat exchanger in the indoor heat exchanger of a refrigeration cycle comprising a compressor, a four-way valve, an outdoor heat exchanger, a throttle means, an indoor heat exchanger and the like. A heating means is provided near the indoor heat exchanger of the refrigerant pipe that connects the throttle means and the indoor heat exchanger, and the output of the heating means is detected by the temperature sensor of the indoor heat exchanger. An air conditioner characterized by being controlled according to temperature.