Sectors
Cold storage and freezing
A blast freezer or cold store holds a deep evaporating temperature against ambient condensing for most of the year. That is a large lift, sustained continuously — exactly where an expansion valve destroys the most work.
The duty
Freezer warehouses and blast freezers typically evaporate somewhere between −25 and −40 °C and condense against ambient air or water, so the temperature lift is large and runs day and night through the year. Most modern cold stores use natural refrigerants: ammonia (R717) in larger industrial plants, CO₂ (R744) in newer and smaller ones.
Because the plant runs continuously, even a modest gain in COP turns into a large number of kilowatt-hours over a year. Cold storage is usually the first place an operator looks to cut an electricity bill, and it is where the physics is most in your favour.
Why the expander fits here
The work an expansion valve destroys grows with the pressure lift, and the recoverable work grows with it too. Deep-freeze duty has the largest lift of any common refrigeration application, so it has the most to recover. The expander turns that pressure drop into work instead of heat, raising the COP and adding refrigerating effect in the evaporator.
Running hours do the rest: a store that runs 8,000 hours a year converts a COP gain into a saving eight thousand hours wide.
What changes on your plant
The expander replaces the expansion valve. The compressor, condenser, evaporator and refrigerant charge stay as they are, so it suits an existing installation as much as a new one. Our first retrofit ran for seven months on an office heat pump at The Green Village with the installation's own installer and an industrial heat pump specialist — the same way we expect a cold-store retrofit to be done, by the party that already knows the plant.
What would it save on your cold store?
Set your refrigerant, temperature lift and running hours in the calculator and read off the modelled COP gain and the electricity it saves.