Refrigeration cycle apparatus and hot water heater

Abstract

A refrigeration cycle apparatus 1A includes: a refrigerant circuit 2 provided with a subcooling heat exchanger 23; a bypass passage 3 extending through the subcooling heat exchanger 23; and a controller 4 for controlling a main expansion means 24 in the refrigerant circuit 2 and a bypass expansion means 31 in the bypass passage 3. The bypass expansion means 31 is controlled so that a bypass side outlet temperature conforms to a saturation temperature at a pressure of a refrigerant to be drawn into a compressor 21, and a degree of superheat at an outlet of an evaporator 25 calculated based on an evaporator outlet temperature is equal to or lower than a predetermined degree of superheat.

Description

technical field [0001] The present invention relates to a refrigerating cycle device for subcooling refrigerant flowing out of a condenser and a warm water heating device using the refrigerating cycle device. Background technique [0002] In the past, there was a refrigeration cycle device, which installed a subcooling heat exchanger on the downstream side of the condenser of the refrigerant pipeline, and made the expanded refrigerant flow into the subcooling heat exchanger to supercool the refrigerant flowing out of the condenser. of refrigerant. For example, disclosed in Patent Document 1 Image 6 A refrigeration cycle apparatus 100 is shown. [0003] This refrigeration cycle apparatus 100 includes a refrigerant line 110 and a bypass 120 for circulating a refrigerant. The refrigerant line 110 is configured by connecting the compressor 111 , the condenser 112 , the subcooling heat exchanger 113 , the main expansion valve 114 , and the evaporator 115 in a ring shape using ...

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Problems solved by technology

[0008] However, as described in Patent Document 1, when the bypass expansion valve 121 is controlled so that the degree of superheat (Tbo-Ts) at the outlet of the subcooling heat exchanger 113 becomes the target degree of superheat, more refrigerant can be Evaporates in the subcooling heat exchanger 113, therefore, the performance of the subcooling heat exchanger 113 cannot be utilized to the fullest

That is, the effect of increasing the enthalpy in the evaporator 115 by heat exchange between the main flow refrigerant and the bypass flow refrigerant and reducing the pressure loss in the low-pressure side refrigerant flow path by bypassing the refrigerant cannot be maximized. Effect

Moreover, if the refrigerant bypassing the evaporator 115 is overheated (superheat), the volume ratio of the refrigerant sucked into the compressor 111 increases, not only the phenomenon that the circulation amount of the refrigerant decreases, but also the discharge of the compressor 111 The temperature will also increase

Therefore, when the outside air that requires a large heating capacity is low temperature, from the viewpoint of controlling the discharge temperature and ensuring reliability, the rotation speed of the compressor cannot be increased too much, and the heating capacity may be insufficient.

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