JPS58179754A - Air conditioner - Google Patents

Abstract

PURPOSE:To prevent the heating performance from rapid decreasing in the titled device by a method wherein an electrical current increase of a compressor is detected while a heat pump is in the heating operation, and an electrical current flowed in an auxiliary heater for heating is controlled to restrict the whole electrical current flowed in a air conditioner less than the designated limited value. CONSTITUTION:A compressor 1, a four-way valve 2, a outdoor heat exchanger 3, a capillary tube 4 and a indoor heat exchanger 5 are connected by piping in ring-shaped form. Said outdoor heat exchanger 3 is provided with an auxiliary heater to supplement the decreasing of heating performance when the open air temperature is lowered. In such an air conditioner, the compressor electrical current increases from the starting of the operation together with the open air temeprature rising as shown in the figure. At this time, when the operating time reaches a time point 2, the compressor electrical current rises to B, also the whole electrical current shown by the full line becomes A (maximum allowable electrical current). Thereafter, the electrical current flowed through the auxiliary heater is controlled by the phase control with a Triac, or by the amplitude control with a transistor according to the value of increase of the compressor electrical current after reaching said time point 2, thereby, the whole electrical current is controlled to the value less than A.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention calculates the value of the total current flowing through an air conditioner during heat pump heating operation in which an indoor heat exchanger is used as a condenser and an outdoor heat exchanger is used as an evaporator. This relates to an overcurrent prevention mechanism that suppresses the current below a preset value.

[Prior art]

Figure 1 shows the basic refrigeration of air conditioners and machines for heating and cooling.
゛Shows a cycle. In FIG. 1, 1 is a compressor, 2 is a four-way valve, and 2d is an operating valve in the four-way valve 2. The solid line indicates the state during heating operation, and the broken line indicates the state during cooling operation.

3 is an outdoor heat exchanger that functions as an evaporator during heating operation and as a condenser during cooling operation.

4 is a capillary tube for pressure reduction, and 5 is an indoor heat exchanger, which functions as a condenser during heating operation and as an evaporator during cooling operation. The flow of refrigerant in Figure 1 is compressed a! during heating operation. The high temperature and high pressure gas refrigerant discharged from the four-way valve 2
Since the switching valve 2a is in the solid line state, the flow flows toward the indoor heat exchanger 5, where it condenses and radiates heat by exchanging heat with the indoor air, and then is depressurized by the capillary tube 4, and is transferred to the outdoor heat exchanger. The air enters the container 3, exchanges heat with outdoor air, absorbs heat through evaporation, and returns to the compressor (2) through the four-way valve (2). In such a heat pump cycle, the operating current of the compressor 1 changes depending on the temperature of the indoor air and the temperature and humidity of the outdoor air. That is, when the indoor air temperature increases by 1- or the outdoor air temperature or humidity layer increases, the operating current of the compressor increases.

By the way, heating air conditioners require heating capacity when the outside air temperature is low, but in heating operation using the heat pump cycle described above, when the outside air temperature becomes low, the amount of heat absorbed in the outdoor heat exchanger decreases. Heating capacity decreases. In order to compensate for this decrease in heating capacity at low temperatures, a heater that utilizes Joule heat is generally installed. This heater is not necessarily needed when the outside air temperature is high because the heat pump heating capacity increases, but the heater may be energized even when the outside air temperature is high because it is troublesome to turn off the heater power. Under such operating conditions, the heater current is added to the increased compressor operating current, and the total current of the air conditioner becomes excessive. In other words, the total current flowing through the air conditioner must be kept below a certain value depending on the capacity of the outlet and indoor wiring to which the air conditioner K is connected, but when the outside temperature is high and the heater is turned on, this value There is a risk of exceeding. In order to prevent this, conventional methods have been used to cut off the heater power supply when the compressor operating current rises to a preset value.

Referring to FIG. 2, the operation according to this conventional method will be explained. Figure 2 shows the current value on the vertical axis and the operating time on the horizontal axis, and shows changes in operating current due to changes in environmental conditions such as outside temperature or indoor temperature (hereinafter referred to as air temperature) over time. This is what is shown. In Figure 2, A is the maximum allowable current that can be passed through the air conditioner, B is the compressor operating current when the heater is turned off (hereinafter referred to as compressor current), and c is the compressor current when the heater is turned on. be.

At the start of operation (■), the air temperature is low and the compressor current shown by the broken line is small, so the heater current is added to the total current shown by the solid line. When the temperature rises and the compressor current increases until it reaches 1 (time point ■), the heater is turned off and the total current that was close to A decreases to a point close to the compressor current. (Compressor current/fan motor current) After that, when the temperature which had been rising by 1- starts to drop, the compressor current decreases, and when it reaches C (at the time of ■), the heater is turned on and the total current increases. There are two inconvenient points in the above driving process. The first point is that when the compressor current reaches 3, the heater is completely cut off, resulting in an extremely low heating capacity. Even if the temperature rises, more powerful heating capacity may be required depending on the conditions, which is inconvenient at such times. The second point is that in order for the heater to return, the air temperature must further decrease to C, minus the differential, rather than the compressor current (+3) when the heater was turned off. At temperatures where the compressor current decreases to (゛), it is quite conceivable that the heater would be required to increase its heating capacity, and this would be inconvenient.

[Purpose of the invention]

The present invention eliminates these disadvantages.

[Summary of the invention]

The present invention provides an air conditioner for both cooling and heating, which is equipped with a refrigeration cycle consisting of a refrigerant control device such as a compressor, a condenser, an evaporator, and a four-way valve, and an auxiliary heater for heating. is detected and the current flowing to the auxiliary heater is controlled in phase by a triac or by a transistor to prevent the total current flowing into the air conditioner from exceeding a set value. .

[Embodiments of the invention]

FIG. 3 shows the operation of an air conditioner equipped with an overcurrent prevention device according to an embodiment of the present invention.

In FIG. 3, the relationship between the vertical and horizontal axes and the meanings of the symbols are the same as in FIG. From the time of starting operation ■, the temperature is -
As L increases, the compressor current shown by the broken line increases and at the point of ■, I(
At the same time, after the total current reaches A, the temperature further increases by -1
- When the compressor current increases, the increase from IJ is detected and the triac or power transistor connected to the heater circuit is controlled. decreases the current flowing through A, reducing the total current to A
The following restrictions apply. That is, the compressor current is 13+α
The next step is to reduce the heater current by α.
This operates a triac or power transistor.

〔Effect of the invention〕

According to the present invention, there is no possibility of a sudden decrease in heating capacity or a lack of heating capacity due to a delay in returning the heater, which were disadvantageous in the conventional example.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the basic form of a refrigeration cycle that can switch between cooling and heating using a four-way valve, Fig. 2 is an explanatory diagram of the operation of an air conditioner equipped with a conventional overcurrent prevention device, and Fig. 3 is a diagram of the present invention. FIG. 2 is an explanatory diagram of the operation of an air conditioner equipped with an overcurrent prevention device according to the present invention. 1... Compressor, 2... Four-way valve, 3... Outdoor heat exchanger, 4... Indoor heat exchanger.

Claims (1)

[Scope of Claims] 1. In an air conditioner for both cooling and heating, which is equipped with a refrigeration cycle consisting of a refrigerant control device such as a compressor, a condenser, an evaporator, and a four-way valve, and an auxiliary heater for heating, the compressor is operated during heating operation. The device is characterized by detecting a rise in current and controlling the phase of the current flowing to the auxiliary heater using a triac or amplitude control using a transistor so that the total current flowing to the air conditioner does not exceed a set value. Air conditioner. 2. The air conditioner according to claim 1, wherein the current of an auxiliary heater for space heating is controlled by detecting an increase in the total current flowing through the air conditioner.