| 摘要 |
PROBLEM TO BE SOLVED: To eliminate any special means such as liquid compression or the like at the time of cooling operation, keep its comfortable feeling during heating operation and further enable an effective load reducing operation to be carried out. SOLUTION: A bypass passage comprising a bypass valve 6 having a flow rate resistance, opened or closed in response to a pressure of refrigerant and a bypass pressure reducing device 7 is arranged from between an outdoor heat exchanger 2 and a pressure reducing device 3 under a freezing cycle over a refrigerant inlet of a compressor 1. An indoor heat exchanger 4 is provided with a refrigerant temperature sensing device 8. At the time of cooling operation, when a pressure of injected refrigerant gas of the compressor 1 exceeds a predetermined value, this bypass passage is operated to reduce its load. At the time of heating operation, a micro-computer 10 calculates an estimated temperature T from a refrigerant temperature To detected by a temperature sensing device 8 in reference to a varying speed of refrigerant temperature and a time lag period, and when this estimated temperature T exceeds a load discriminating value, it is estimated that the state becomes an over-loaded state, an outdoor blower 14, an indoor blower 13 and the compressor 1 are controlled to perform a reduction in load. |
