JPS6222947A - Air conditioner - Google Patents

Abstract

PURPOSE:To save the power consumption required for preheating the compressor by causing the start supplying the current for preheating when both the room temperature and outside temperature are below their respective set values. CONSTITUTION:When both the room temperature and outside temperature go lower than their respective set temperatures, a preheating command signal 11 is fed from the control circuit 5 to the inverter device 4, and the inverter device 4 energizes the coil 7a of the preheating device 7 to preheat the compressor 3. When either one of the room temperature or outside temperature goes higher than its set temperature, the control circuit 5 stops outputting the preheating command signal 11. Therefore, while the temperature of the compressor 3 remains high after the heating operation stops, temperature detected by the outside temperature sensor 10 does not go higher than its set temperature, and therefore, the current is not supplied to the preheating device 7, saving that power consumption.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a heat pump type air conditioner capable of cooling and heating, and particularly relates to an improvement of an air conditioner having a preheating device for preheating the compressor before heating operation.

[Technical background of the invention and its problems]

Generally, when performing heating operation in a heat pump type air conditioner, if the heating operation is stopped for a long period of time, the compressor will become cold and the temperature will become almost equal to the outside temperature. The oil will dissolve into the refrigerant. If the compressor was started in this state, there was a risk of oil foaming, seizure, etc., and damage to the compressor.

Therefore, conventional methods have been used to prevent oil forming and seizure by installing a preheater inside the compressor's sealed case or preheating the compressor by energizing the windings of the electric element to maintain the compressor's internal temperature higher than the outside temperature. The aim was to prevent such incidents.

By the way, in conventional air conditioners, the heating operation is controlled by detecting the indoor temperature, and the preheating of the compressor is also controlled based on the indoor temperature. That is, as shown in FIG. 3, when the indoor temperature drops below a set temperature, for example 20° C., preheating current is started to preheat the compressor. However, this does not take the outside air temperature into account at all, so if the indoor temperature is below the set temperature after the heating operation is stopped, even though the compressor is bulky, the preheating current will be applied immediately after the heating operation is stopped. However, there was a problem in that the compressor was overheated as well as wasting power.

[Purpose of the invention]

The present invention has been made in consideration of the above circumstances, and an object of the present invention is to provide an air conditioner that saves power required for compression-like preheating.

[Summary of the invention]

In order to achieve the above object, the present invention starts preheating energization when both indoor temperature and outdoor temperature are below each set value, and when either temperature exceeds the set value, preheating energization is started. It is characterized by avoiding stopping.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 is a block diagram of an embodiment of the present invention, showing a split type air conditioner separated into an indoor unit 1 and an outdoor unit 2. As shown in FIG.

The indoor unit 1 is provided with an indoor heat exchanger (not shown), and the outdoor unit 2 is provided with an outdoor heat exchanger, a four-way valve, and a pressure reducing device (not shown) in addition to the compressor 3. The compressor 3, the four-way valve, the outdoor heat exchanger, the pressure reducing device, and the 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 The room is heated and cooled by switching.

The compressor 3 is electrically connected to an inverter @4,
The inverter device 4 temporarily converts the commercial AC power into DC,
This is further converted into a three-phase alternating current of, for example, 30 to 1201-1z, and the load of the refrigeration cycle (V internal temperature, outdoor temperature, etc.) is transmitted from the control circuit 5 provided in the indoor unit 1.
The compressor 3 is driven to rotate according to the load of the refrigeration cycle upon receiving a frequency command signal 6 corresponding to the refrigeration cycle.

The preheating device 7 is formed by commonly 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 compression tlI3 is It is possible to generate heat in the winding 7a without rotating the winding 7a. The preheating device 7 may include a heater provided separately within the compressor 3 in addition to the winding 7a.

31 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, and by switching the air conditioning/heating changeover switch 8, a four-way valve (not shown) is switched via the control circuit 5. It is designed to perform heating and cooling operation.

In addition, the control circuit 5 is connected to an indoor temperature detector 9 via a signal line.
and an outdoor temperature detector 10 are connected. 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 the outdoor heat exchanger or refrigerant pipe (not shown) in the outdoor unit 2 to detect the outside air. It is designed to detect temperature. Detect both these temperatures! The control circuit 5 which receives the detection output from 9.10 has its own set temperature, for example, the indoor temperature is set to 15°C and the outdoor temperature is set to -5°C. These set temperatures are each set to a temperature that is expected to be reached after the time for the compressor 3 to cool down to near the outside air temperature, for example, 2 hours after the heating operation is stopped.

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 sends the preheating command signal 11 to the inverter device 4.
On the other hand, when at least one of the two detected temperatures exceeds the set temperature, a preheating command signal 11 is given.
output is now 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 changes in the indoor temperature shown by the solid line and the outdoor temperature shown by the broken line after the heating operation is stopped. ing. After the heating operation is stopped, both temperature detectors will be activated over time, and after about 2 hours or more,
The indoor temperature drops below the child's set temperature, for example 15°C. Next, when the outdoor temperature falls below the set temperature with the passage of time, both the outdoor temperature and the indoor temperature become below each set temperature. As a result, a preheating command signal 11 is given from the control circuit 5 to the inverter device 4, and the inverter device 4 energizes the winding 7a of the preheating device 7 to preheat the compressor 113. After this preheating, when at least one of the indoor temperature and the outside temperature rises above the set temperature, the control circuit 5 stops outputting the preheating command signal 11. As a result, the inverter device 4 stops energizing the preheating device 7 and stops preheating.

Therefore, after the heating operation is stopped, while the compression 13 is still at a high temperature, the temperature detected by the outdoor temperature detector 10 does not reach the set temperature (for example, -5°C) or lower, so the preheating device 7
energization is not performed, and power can be saved accordingly.

〔Effect of the invention〕

As explained above, the present invention provides an indoor temperature detector for detecting indoor temperature and an outdoor temperature detector for detecting outdoor air temperature in an air conditioner that preheats a preheating device provided in a compressor by energizing it when heating operation is stopped. A control circuit is provided to energize the preheating device when both detected temperatures are below each set temperature.

Therefore, according to the present invention, since preheating of the preheating device is started by detecting both the indoor temperature and outdoor temperature, preheating is not performed when the compressor is at a sufficiently high temperature after the heating operation is stopped, so that overheating of the compressor is prevented. It is possible to prevent this and save power consumption.

Further, since the outdoor temperature detector can be used for defrosting detection of the outdoor heat exchanger, the number of parts and cost can be reduced.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the configuration of one embodiment of the present invention, Fig. 2 is a graph for explaining the compressor preheating operation of the embodiment shown in Fig. 1, and Fig. M3 is a graph for explaining the preheating operation of the conventional example. This is a graph for 1...Indoor unit, 2...Outdoor unit, 3...
- Compressor, 4... Inverter device, 5... Control circuit, 7... Preheating device, 7a... Winding wire, 9... Indoor temperature detector, 10... Outdoor temperature detector, 11... Preheating command signal. Representative Patent Attorney Nori Chika Ken Shu
Yuyama Yuki Ogiku 2nd figure 3rd figure

Claims (1)

[Claims] In an air conditioner that preheats the preheating device installed in the compressor by energizing it when the heating operation is stopped, both the detected temperature of the indoor temperature detector that detects the indoor temperature and the outdoor temperature sensor that detects the outside air temperature are at each set temperature. An air conditioner comprising a control circuit that energizes the preheating device when the following conditions are met.