The air-cooled condenser designer calculates required condenser capacity and recommends a class-typical unit using the Total Heat of Rejection (THR) method from ASHRAE Refrigeration Handbook 2022, Chapter 35. THR = refrigerating capacity × (1 + 1/COP), adjusted for compressor heat of compression at the specified saturated discharge temperature (SDT). Hot-climate ambient derate is applied: medium-temperature systems lose roughly 2.0%/°C above the ASHRAE reference ambient of 95°F (35°C); low-temperature systems lose roughly 2.7%/°C. A hard floor of 60% rated capacity is applied regardless of ambient. The tool warns when saturated condensing temperature (SCT) reaches 131°F (55°C) — above this threshold compressor warranty may be voided and oil carryover risk increases. Validated against Bitzer Software and Heatcraft NROES unit selection for hot U.S. summer design conditions (Phoenix, Las Vegas, Gulf Coast).
References: ASHRAE Refrigeration Handbook 2022 Ch. 35; Bitzer Refrigerants Report 25 (2022); Heatcraft Refrigeration Product Selection Guide.