JPS60134168A - Method of peoration of air conditioner - 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 [Technical Field of the Invention] The present invention relates to a method of operating an air conditioner, and particularly relates to an air conditioner that can be operated at 0N10F, and has a plurality of indoor heat exchangers. The present invention relates to an operating method for an air conditioner that not only allows stable operation regardless of the number of indoor heat exchangers that are brought into operation, but also eliminates the risk of freezing of the evaporator.

[8 Technical aspects of the invention and its problems] Generally, as an air conditioner for simultaneously air-conditioning multiple rooms, etc., an air conditioner in which multiple indoor heat exchangers are connected to one compressor is known. ing.

For example, during heating operation, this air conditioner heats each room by sequentially circulating and supplying the refrigerant discharged from the compressor to indoor heat exchangers connected in parallel. The discharge temperature is detected, and the opening degree of the electric expansion valve is adjusted to maintain the discharge temperature at a set value regardless of the number of indoor heat exchangers in operation, thereby controlling the refrigerant flow rate.

By the way, the amount of heat transfer on the condensing side, that is, the amount of heat transfer on the indoor heat exchanger side, increases significantly when multiple indoor heat exchangers are operated than when one indoor heat exchanger is operated. Condensing pressure decreases.

For this reason, electric expansion valves have been controlled to forcibly raise the discharge temperature to the above set value by 1C, but in this case, the expansion valves have to be over-throttled, and as a result, the evaporator The amount of superheat on the side becomes large and it becomes a kind of gas starvation state, so I! ! There was a risk that the chamber capacity would decrease or the evaporator would freeze.

The present invention has focused on the above-mentioned problems and has been devised to effectively solve them.

[Objective of the Invention] The object of the present invention is to not only enable stable operation in an air conditioner that uses a plurality of indoor heat exchangers regardless of the number of indoor heat exchangers that are brought into operation, but also to improve the performance of the evaporator. An object of the present invention is to provide a method of operating an air conditioner that can eliminate the risk of freezing.

[Summary of the Invention] The present invention includes a plurality of indoor heat exchangers, and detects discharge dryness i of a compressor, and connects the heat exchangers so that the detected value maintains a preset discharge humidity setting value. In a method of operating an air conditioner that controls the flow rate of refrigerant flowing into the air conditioner, the discharge temperature setting value is successively lowered as the number of indoor heat exchangers that reach the operating state increases, thereby increasing the temperature of the air conditioner. It accomplishes its purpose.

[Embodiments of the invention] The method of the present invention will be explained in detail below based on the accompanying drawings.

Figure 1 shows the method of the present invention in action! FIG. 2 is a plan view showing a refrigeration cycle as a second embodiment of the invention, and FIG. 2 is a flow chart 17 showing the operation of the expansion valve 19 control section of FIG.

As shown in the figure, this refrigeration cycle includes a compressor 2 for compressing refrigerant into a refrigerant passage 1, an indoor heat exchanger 3, an electric expansion valve 4 driven by a motor (not shown), and an outdoor heat exchanger 6, respectively. It is constructed by intervening. In particular, this refrigeration cycle has a plurality of indoor heat exchangers 3a and 3b that are placed in each seedling in order to simultaneously cool and heat a plurality of rooms, and these heat exchangers are parallel to the refrigerant passage 1. It is connected to. In the illustrated example, only two indoor heat exchangers are shown for simplicity.

Refrigerant passage 1 in which the indoor heat exchangers 3a and 3b are interposed
A and 1b each have an automatic on-off valve 7a.

7b is interposed, and the 0N10FF emitted by these
The opening/closing signal, that is, the operation signal of each unit, is transmitted to the expansion valve control section 8, which is the main part for implementing the method of the present invention.

On the other hand, a discharge temperature detector 9 for detecting the discharge temperature of the refrigerant gas is provided on the discharge side of the compressor 2, and the discharge temperature detected here can be transmitted to the expansion valve control section 8. It has become.

A preset discharge temperature setting value is stored in this expansion valve control unit 8, and the opening degree of the expansion valve 4 is changed so that the discharge temperature is maintained at this set value. The flow rate is controlled.

In the expansion valve control unit 8, the preset discharge temperature setting value T8 is adjusted sequentially in response to an increase in the number of indoor heat exchangers 31 that are brought into operation, that is, the number of indoor heat exchangers through which the refrigerant passes. It is automatically made smaller.

For example, the constant Tt, 'T+(Tt
>1-+), and one of the indoor heat exchangers -
When only the indoor heat exchangers are in operation, the T value with the larger value is used as the discharge temperature set value, and furthermore, when the two indoor heat exchangers are in operation, T! T+'', which is smaller than , is taken as the discharge temperature set value.

If you have three or more indoor heat exchangers, set the discharge temperature set value to a smaller value such as °T'3, T'4, etc., and gradually lower this value. Of course it is. - Furthermore, the 0N10FF state of the indoor heat exchangers 3a and 3b is as follows:
It can be detected from the ON/OF Itil 111 signal (operation signal) emitted from the lζζ on-off valve 7a7b interposed in the refrigerant passages 1a and Ib.

Next, the method of the present invention will be explained based on the refrigeration cycle configured as described above with reference to FIG.

In the heating operation state, the refrigerant gas sent from the compressor 2 to 11 is condensed and liquefied in the indoor heat exchanger 3, and is circulated and introduced into the compressor 2 again after passing through the expansion valve 4 and the outdoor heat exchanger 6. .

On the other hand, the discharge temperature detected by the discharge temperature detector 9 provided on the discharge side of the compressor 2 is transmitted to the expansion valve control section 8, which controls the opening of the expansion valve 4 to maintain a preset discharge setting value. The degree adjustment is made.

Here, the discharge temperature set value is changed depending on the number of indoor heat exchangers in operation. For example, when one unit (one room) is operated, the setting +11iT is set to T1, and when two units (two rooms) are operated, the set value is set to T8. It is assumed to be 11, which is smaller than T1.

The temperature difference between T1 and T+ is optimally set depending on the capacity of the indoor heat exchanger.

To explain this control in detail based on the flowchart in Figure 2, the two indoor heat exchangers are designated as A and B heat exchangers for convenience, and first, 0N10FF of A heat exchanger is determined, and if it is ON, that is, the operating state. In this case, 0N10FF of the B heat exchanger is further determined. In addition, the heat exchanger is 0N1
Along with the 0FF, the transmission ff1 unit is also turned 0N10FF. When the B heat exchanger is ON, two heat exchangers are in operation, so T+ is set as the discharge setting value T8.

When the B heat exchanger is OFF, only one heat exchanger is in operation, so T1 is set as the set value T8.

On the other hand, when the A heat exchanger is O'FF, that is, in a stopped state, 0N10F and F of the B heat exchanger are further determined. When heat exchanger B is ON, only one heat exchanger is in operation, so T1 is set as the lower set value. If the B heat exchanger is also OFF, all the heat exchangers are in a stopped state, so no setting is made as the setting (aT8).These judgments are always made while the air conditioner is operating.

In this way, when operating multiple indoor heat exchangers (during 2 idle operations)
When only one indoor heat exchanger is in operation, there is no need to raise the discharge temperature, which prevents the electric expansion valve from becoming throttled (as seen from the superheat state) and allows the valve to open. You can adjust the 1 degree to slightly open.

Therefore, optimal refrigerant control is possible, which not only allows stable operation of the refrigeration cycle, but also prevents the evaporator (outdoor heat exchanger) from freezing due to gas starvation.

Incidentally, Fig. 3 is a graph showing the discharge temperature setting value in a so-called inverter control method in which the rotation speed of the motor is controlled by changing the operating frequency of the compressor.
The mark indicates the discharge temperature setting value for 1 room when only one heat exchanger is operated, and the 0 mark indicates the discharge temperature setting value for 2 rooms when operating 2 heat exchangers. Even in this case, at the same operating frequency, the discharge temperature PjI set value for the two rooms is set lower than the discharge temperature set value for the first room, so that the same effects as described above can be obtained.

[Effects of the Invention] In summary, according to the method of the present invention, the following excellent effects can be exhibited.

(1) With the increase in the number of indoor heat exchangers that come into operation, the discharge temperature setting value has been lowered, which eliminates the need for over-throttling the expansion valve, allowing optimal refrigerant control and stabilizing the refrigeration cycle. can be driven to.

(2) Also, since the expansion valve will not be over-throttled,
It is possible to avoid a starvation operation state, and also to prevent the evaporator (outdoor heat exchanger) from freezing.

(3) Since the method is simple, the method of the present invention can be easily applied to existing air conditioners.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing a refrigeration cycle as an example for carrying out the method of the present invention, FIG. 2 is a flowchart showing the operation of the expansion valve control section in FIG. 1, and FIG. It is a graph showing the relationship between the operating frequency and the discharge temperature setting value. In the figure, reference numerals i, ia, and 1b are refrigerant passages, 2 is a compressor, 3 is an indoor heat exchanger, 4 is an expansion valve, 8 is a discharge valve control section, and 9 is a discharge temperature detector. Representative Patent Attorney Kensuke Chika (1 other person) Daiichi Kōdō δ

Claims (1)

[Claims] The refrigerant passage has a plurality of indoor heat exchangers freely connected in 0N10FF and in parallel, and detects the discharge temperature of the compressor and adjusts the temperature so that the detected value maintains a preset discharge temperature setting value. In a method of operating an air conditioner in which the flow rate of refrigerant flowing into an exchanger is controlled, the discharge temperature set value is successively lowered as the number of indoor heat exchangers that reach an operating state increases. A method of operating an air conditioner characterized by the following.