Abstract: A polyester resin containing: a diol constituent unit containing a unit a1 derived from spiroglycol represented by formula (1) and a unit a2 derived from ethylene glycol; and a dicarboxylic acid constituent unit containing a unit b derived from terephthalic acid and/or an ester thereof. A content of the unit a1 is from 5 to 60 mol % and a content of the unit a2 is from 30 to 95 mol %, based on a total amount of the unit a1 and the unit a2. A content of the unit b is from 80 to 100 mol % based on a total amount of the dicarboxylic acid constituent unit.

Abstract: A refrigeration cycle apparatus includes a first refrigerant circuit and a second refrigerant circuit so as to improve the efficiency of operations. A first refrigerant circuit using a first refrigerant having a pressure of 1.2 MPa or less at 30° C. and a second refrigerant circuit using a second refrigerant having a pressure of 1.5 MPa or more at 30° C. are provided, and a dual cycle operation in which the first refrigerant circuit and the second refrigerant circuit are simultaneously operated to exchange heat between the first refrigerant and the second refrigerant and a single cycle operation in which the first refrigerant circuit is operated without operating the second refrigerant circuit to perform a cooling operation or heating operation are enabled in a switchable manner.

Abstract: A polyester resin containing: a diol constituent unit containing a unit a1 derived from spiroglycol represented by formula (1) and a unit a2 derived from ethylene glycol; and a dicarboxylic acid constituent unit containing a unit b derived from terephthalic acid and/or an ester thereof. A content of the unit a1 is from 5 to 60 mol % and a content of the unit a2 is from 30 to 95 mol %, based on a total amount of the unit a1 and the unit a2. A content of the unit b is from 80 to 100 mol % based on a total amount of the dicarboxylic acid constituent unit.

Abstract: A polyester resin containing: a diol constituent unit containing a unit a1 derived from spiroglycol represented by formula (1) and a unit a2 derived from ethylene glycol; and a dicarboxylic acid constituent unit containing a unit b derived from terephthalic acid and/or an ester thereof. A content of the unit a1 is from 5 to 60 mol % and a content of the unit a2 is from 30 to 95 mol %, based on a total amount of the unit a1 and the unit a2. A content of the unit b is from 80 to 100 mol % based on a total amount of the dicarboxylic acid constituent unit.