Heat pump cycle

Abstract

According to the present invention, a coolant shortage determination unit (S2, S3, S6, S8, S9) determines that a coolant shortage state is present when the high-pressure-side coolant pressure (Pd) between the discharge port of a compressor (11) and the entrance of the decompression unit (13) is lower than a predefined first reference pressure (KPd1), if the external air temperature (Tam) is equal to or higher than a predefined reference external air temperature (KTam); and determines that a coolant shortage state is present when the high-pressure-side coolant pressure (Pd) is lower than a predefined second reference pressure (KPd2), in a state in which the compressor (11) is in operation, if the external air temperature (Tam) is lower than the reference external air temperature (KTam). When the coolant shortage determination unit determines that a coolant shortage state is present, a compressor controller (S4) reduces the coolant discharge capacity of the compressor (11).

Description

[0001] This application claims priority based on Japanese application number 2012-146058 for which it applied on June 28, 2012, and uses the description content here. technical field [0002] The present application relates to a heat pump cycle system for heating a fluid by absorbing heat from an external air. Background technique [0003] Conventionally, there is known a vapor compression type refrigeration cycle system (heat pump cycle system) that is applied to an air-conditioning apparatus and cools blown air sent to a space to be air-conditioned. In this type of heat pump cycle system, when the flow rate of the refrigerant circulating in the cycle system decreases, such as when the refrigerant leaks to the outside or when the outside air temperature is low, the refrigerant circulates through the cycle system together with the refrigerant and returns The return amount of the refrigerating machine oil to the compressor decreases, which may adversely affect the durability ...

AI Technical Summary

Problems solved by technology

Therefore, when it is judged that the flow rate of the refrigerant is insufficient when the outside air temperature is low as in Patent Document 1, and the compressor is stopped, the blown air cannot be heated, and thus the space to be air-conditioned cannot be heated.

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