JPH0348419B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a heat pump type air conditioner, and more particularly to an air conditioner having a preheating device for preheating a compressor while heating operation is stopped.

(Prior art) In general, compared to other heating equipment, when heating operation is performed in winter in a heat pump type air conditioner, it takes a long time from the start of heating operation until hot air at a predetermined temperature is blown out, resulting in a longer heating start-up time. , comfort was sometimes inferior.

To solve this problem, conventional heat pump air conditioners are equipped with a preheating device on the compressor, and when the indoor temperature is low when the heating operation is stopped, the preheating device is energized to maintain the compressor at a high temperature. By making it possible to quickly blow out warm air when the next heating operation starts, heating start-up time is shortened and comfort is improved.

(Problem to be Solved by the Invention) By the way, in conventional air conditioners, as shown in Figure 3, energization to the preheating device of the compressor starts when the indoor temperature drops below the set temperature, for example, 20°C. Was. However, the operation of this preheating device is performed while the heating operation is stopped, and if the next heating operation starts for a short time after the heating operation stops, it is not a big problem since the preheating device only needs to be energized for a short time. If the preheating device is stopped for a long time before the next heating operation starts, the preheating device is energized for a long time, resulting in an increase in unnecessary power consumption. In particular, the preheating device is basically a type of heater, and its operation consumes a considerable amount of power, so from the viewpoint of power consumption, it is desirable to avoid energizing the preheating device as much as possible. .

[Structure of the Invention] (Means for Solving the Problems) The present invention provides an indoor temperature detector for detecting indoor temperature in an air conditioner that preheats a preheating device provided in a compressor by energizing it when heating operation is stopped. The device is characterized by being equipped with an outdoor temperature detector that detects the outdoor temperature, and a control circuit that energizes the preheating device when both the detected temperatures of the indoor temperature detector and the outdoor temperature detector are below the respective set temperatures. There is.

(Function) When the heating operation is stopped, the preheating device is energized only when the indoor temperature is lower than the set temperature and the outdoor temperature is also lower than the set temperature. By energizing, it is possible to both shorten heating start-up time and save power consumption in the preheating device.

That is, when the indoor temperature is low but the outdoor temperature is high, the temperature of the refrigerant discharged from the compressor rises in a short time after heating starts, and moderately warm air is blown into the room in a short time. Also, if the outdoor temperature is low but the indoor temperature is high, it takes time for the temperature of the refrigerant discharged from the compressor to reach an appropriate high temperature, but since the indoor temperature is high, the air conditioner's suction temperature is high. Even when the temperature of the heat exchanger is lower than normal, the blowing temperature of the air conditioner will be high, and a suitable amount of warm air will be blown into the room in a short period of time. Therefore, by energizing the preheating device only when the indoor temperature is lower than the set temperature and the outdoor temperature is also lower than the set temperature, heating start-up time can be shortened and the power consumption of the preheating device can be saved. Can be successfully achieved.

(Example) Hereinafter, an example of the present invention will be described with reference to FIGS. 1 and 2.

FIG. 1 is a block diagram of an embodiment of the present invention.
This figure shows a split type air conditioner that is separated into an indoor unit 1 and an outdoor unit 2.

The indoor unit 1 is equipped with an indoor heat exchanger (not shown), and the outdoor unit 2 includes a compressor 3 as well as
An outdoor heat exchanger, a four-way valve, and a pressure reducing device (not shown) are provided. These compressor 3, four-way valve, outdoor heat exchanger, pressure reducing device, and indoor heat exchanger are sequentially and annularly connected by refrigerant piping (not shown) to form a closed refrigeration cycle that circulates the refrigerant, and the four-way valve is switched. The interior is now heated and cooled.

The compressor 3 is electrically connected to an inverter device 4, and the inverter device 4 once converts the commercial AC power into DC power, and further converts the commercial AC power into DC power at a frequency of, for example, 30 to 120Hz.
It receives a frequency command signal 6 according to the load of the refrigeration cycle (indoor temperature, outdoor temperature, etc.) from the control circuit 5 provided in the indoor unit 1, and converts it into a three-phase alternating current according to the load of the refrigeration cycle. The compressor 3 is driven to rotate.

The preheating device 7 is formed by using the winding 7a of the electric element of the compressor 3 as a preheating winding, and by supplying low power at high frequency and low voltage from the inverter device 4 to the winding 7a, the compressor It is possible to generate heat in the winding 7a without rotating the winding 7a. Note that the preheating device 7 may be one in which a heater is provided separately within the compressor 3 in addition to the winding 7a.

The control circuit 5 is provided with an air conditioning/heating changeover switch 8 for switching between a heating operation 8a and a cooling operation 8b.By switching the air conditioning/heating changeover switch 8, a four-way valve (not shown) is switched via the control circuit 5 to perform air conditioning/heating. I am learning to drive.

Furthermore, an indoor temperature detector 9 and an outdoor temperature detector 10 are connected to the control circuit 5 via signal lines. The indoor temperature detector 9 is installed in the indoor unit 1 to detect the indoor temperature, and the outdoor temperature detector 10 is installed in an outdoor heat exchanger or refrigerant pipe (not shown) in the outdoor unit 2 to detect the indoor temperature. It is designed to detect temperature. The control circuit 5 which receives detection outputs from both temperature detectors 9 and 10 stores respective set temperatures, and for example, the indoor temperature is set to 15°C and the outdoor temperature is set to -5°C. These set temperatures are set so that it does not take too long for the air conditioner to start heating up when the next heating operation is started. In other words, if the indoor temperature is 15°C or higher, even if the outdoor temperature is -5°C or lower and the start-up of the refrigeration cycle is a little slow, the temperature of the indoor heat exchanger will be lower than normal because the air conditioner's suction temperature (indoor temperature) is high. Appropriately warm air is blown out before the temperature reaches a predetermined temperature. On the other hand, if the outdoor temperature is -5°C or higher, the indoor temperature is 15°C.
By starting the compressor even in low temperature conditions below ℃,
The temperature of the indoor heat exchanger will rise rapidly, and hot air will be blown out in a short period of time.

When the control circuit 5 detects that both the detected temperatures detected by the temperature detectors 9 and 10 are below the respective set temperatures, the control circuit 5 gives a preheating command signal 11 to the inverter device 4, and When at least one of the two detected temperatures exceeds the set temperature, the output of the preheating command signal 11 is stopped.

The inverter device 4 energizes the preheating device 7 upon receiving the preheating command signal 11, and stops energizing the preheating device 7 when the input of the preheating command signal 11 stops.

Next, the operation of this embodiment will be explained based on FIG. 2.

In order to explain the preheating operation of this embodiment, Figure 2 shows the temperature on the vertical axis and the time on the horizontal axis, and mainly shows the changes after the heating operation is stopped between the indoor temperature shown in practice and the outdoor temperature shown by the broken line. ing. After the heating operation is stopped, the indoor temperature gradually decreases. For example, assuming that the air conditioner is stopped at bedtime, the outdoor temperature will decrease as the night approaches. After two hours have passed, the indoor temperature first drops below the set temperature of 15°C. However, in this state, the outdoor temperature is still above the set temperature of -5°C, so the preheating device 7 is not energized.After that, the outdoor temperature decreases and the set temperature is -5°C.
If the temperature falls below, both the indoor temperature and outdoor temperature will be below their respective set temperatures. As a result, a preheating command signal 11 is given from the control circuit 5 to the inverter device 4,
The inverter device 4 energizes the winding 7a of the preheating device 7 to preheat the compressor 3. Therefore, when the heating operation is started early in the morning, the compressor 3 will have been appropriately heated, so hot air will be blown out from the air conditioner in a short period of time, and the start-up time will be shortened.

Further, when at least one of the indoor temperature and outdoor temperature rises above the set temperature during preheating, the control circuit 5 sends a preheating command signal 11
Stop outputting. As a result, the inverter device 4 stops energizing the preheating device 7 and stops preheating.

Therefore, after stopping the heating operation, the power consumption in the preheating device 7 can be reduced by energizing the preheating device 7 only when both the indoor temperature and the outdoor temperature are low and the start-up is slow when the next heating starts. You can save money.

In addition, the outdoor temperature detector 10 can also be used to detect defrosting of the outdoor heat exchanger, thereby reducing the number of parts and cost.

(Effects of the Invention) As explained above, the present invention provides an indoor temperature detector that detects indoor temperature and an outdoor temperature in an air conditioner that preheats a preheating device provided in a compressor by energizing it when the heating device is stopped. By providing an outdoor temperature detector and a control device that energizes the preheating device when the detected temperatures of both temperature detectors are below each set temperature, both indoor and outdoor temperatures can be maintained after heating operation is stopped. Since the preheating device is energized only when the temperature is low and the start-up of the air conditioner is delayed at the start of the next heating operation, it is possible to improve the start-up time of the air conditioner and save power consumption in the preheating device. I can do it.

[Brief explanation of drawings]

Figure 1 is a block diagram showing the configuration of an embodiment of the present invention, Figure 2 is a graph for explaining the compressor preheating operation of the embodiment shown in Figure 1, and Figure 3 is for explaining the preheating operation of a conventional example. This is a graph. 1...Indoor unit, 2...Outdoor unit, 3
... Compressor, 4 ... Inverter device, 7 ... Preheating device, 7a ... Winding wire, 9 ... Indoor temperature detector, 1
0...Outdoor temperature detector, 11...Preheating command signal.

Claims (1)

[Claims] 1. In an air conditioner that preheats a preheating device provided in a compressor by energizing it when heating operation is stopped, an indoor temperature detector for detecting indoor temperature and an outdoor temperature detector for detecting outdoor temperature are provided, and the indoor temperature detection An air conditioner comprising: a control circuit that energizes the preheating device when the temperatures detected by both the indoor temperature sensor and the outdoor temperature sensor are below the respective set temperatures.