Extreme cold: CO₂ cascade heat pump for −40°C ambient heating
Illustrative CO₂ (R744) + R515B cascade concept for district / industrial heating where fluorocarbon cascades lose capacity in deep cold.
Engineering data
Project background
An anonymized northern industrial park needed reliable winter heat. Legacy fluorocarbon cascade units tripped or faded below about −25°C, forcing electric/gas boilers online for long hours.
Source / inputs
Design ambient −40°C. Sink 80°C-class hot water. Duty ~150 kW-class train. PLACEHOLDER numbers for screening only.
Heat pump solution
CO₂ low stage for deep-cold evaporation density + R515B high stage for useful leaving-water temperature; supervisory logic brings boiler peaking below envelope.
COP & savings
Illustrative COP ~2.0 at −25°C class points; ~1.6–1.9 near −30°C extremes—verify on rating sheet. Not measured field data.
Investment / ROI notes
Higher CAPEX than light commercial boxes; illustrative payback 3–6 years vs electric boiler under stated hours—site tariffs required.