Patent ID: 9746212
Date: 2017-08-29
CPC Classifications: F25B

Claim:
1. A refrigerating and air-conditioning apparatus configured to operate in a cooling operation and in a heating operation, which comprises: an outdoor unit including a compressor, a flow switching device, a refrigerant vessel, a heat-source-side heat exchanger, a pressure reducing device, and a refrigerant heat exchanger; an indoor unit including a load-side heat exchanger; a discharge temperature detecting device configured to detect a discharge temperature of a refrigerant discharged from the compressor; a supercooling degree detecting device configured to detect a degree of supercooling of a refrigerant at an outlet of a heat exchanger serving as a condenser, the heat exchanger being one of the heat-source-side heat exchanger and the load-side heat exchanger; a controller configured to control an opening degree of the pressure reducing device in accordance with the discharge temperature detected by the discharge temperature detecting device and the degree of supercooling detected by the supercooling degree detecting device; and a gas-side connecting pipe and a liquid-side connecting pipe each of which connects the outdoor unit to the indoor unit to form a refrigerant circuit including a different sequential arrangement of the compressor, the flow switching device, the load-side heat exchanger, the refrigerant heat exchanger, the pressure reducing device, the heat-source-side heat exchanger, and the refrigerant vessel in each of the cooling operation and the heating operation, wherein in the heating operation the refrigerant circuit includes uninterrupted and sequential flow of refrigerant from the refrigerant vessel to the refrigerant heat exchanger and from the refrigerant heat exchanger to the compressor in series, and the refrigerant heat exchanger transfers heat between a refrigerant flowing between the pressure reducing device and an outdoor-unit liquid pipe connecting portion which is a connecting portion of the liquid-side connecting pipe on a side of the outdoor unit and a refrigerant on an outlet side of the refrigerant vessel, wherein the controller sets a target supercooling degree and a target discharge temperature, the controller being configured to maximize operating efficiency of the apparatus based on a relationship between the target supercooling degree and the target discharge temperature maximizing operating efficiency of the apparatus, the relationship between the discharge temperature range of the compressor and the target supercooling degree including five regions as follows: wherein the controller is configured to: increase the opening degree of the pressure reducing device where the discharge temperature detected by the discharge temperature detecting device and the degree of supercooling detected by the supercooling degree detecting device belong to the second region of the five regions.