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In a cold storage room the evaporator - also called a unit cooler, air cooler or cold room evaporator - is the finned-tube heat exchanger with fans that hangs from the ceiling or wall inside the room. Cold refrigerant (or chilled glycol) flows through its tubes; the fans draw room air across the fins; the air gives up heat (and moisture) to the refrigerant and returns to the room colder. The compressor and condenser outside the room do the rest of the cycle, but the evaporator is the only component that touches the stored product's air, so its selection decides room temperature, humidity, air distribution and defrost behaviour. CSTHEATEXCHANGER manufactures cold storage evaporators from small commercial unit coolers to industrial blast-freezer, IQF and ammonia evaporators, designed for R404A, R410A, CO2, ammonia, glycol and other refrigerants.
Refrigerant enters the coil as a cold low-pressure liquid (direct expansion), as pumped liquid (ammonia or CO2 recirculation), or as chilled glycol.
Fans draw room air across the finned coil.
Heat moves from air to refrigerant. In a DX coil the refrigerant boils; in a pumped or glycol coil it warms.
Moisture condenses or frosts on the fins because the coil surface is below the room's dew point.
Cold air is thrown back into the room, ideally in a pattern that reaches every pallet position.
Periodically the coil is defrosted — electric heaters, hot gas or water — and the melt water drains through the drain pan.
A cold storage evaporator is therefore judged on four things at once: cooling capacity at the design temperature difference, air throw and distribution, the frost/defrost cycle, and hygiene.
Type | Room | Key design points | CSTHEATEXCHANGER product |
|---|---|---|---|
Commercial unit cooler | Small chill and freezer rooms, 0 to –25 °C | Compact; electric defrost; ceiling-mounted | Unit Cooler for Cold Room, Ceiling Unit Cooler, Commercial Unit Cooler |
Dual-flow / dual-discharge | Long rooms, corridors | Air thrown both ways from a central mounting | Dual Flow Unit Cooler |
Industrial unit cooler | Large chill/freezer stores | High airflow and throw; hot-gas or water defrost; wide fin pitch | Industrial Unit Cooler, Cold Room Evaporator |
Blast freezer / blast chiller | –35 to –45 °C tunnels and rooms, carcass chilling | Very high air velocity; wide fin spacing for frost; robust fans | Blast Freezer Unit Coolers, Air Blast Coolers |
Spiral / IQF | Spiral and IQF freezers | Stainless construction; hygienic; fits the freezer frame | Spiral & IQF Evaporator, IQF Stainless Steel Evaporator |
Ammonia / pumped | Industrial NH3 plants | Stainless or aluminium tubes; pumped liquid feed; hot-gas defrost | Ammonia Evaporator, Ammonia Air Cooler |
Glycol | Secondary-refrigerant rooms | Water-side coil; no refrigerant in the room | Glycol Air Cooler |
Stainless steel | Food, eggs, vegetables, poultry farms, 0–10 °C | 316L tubes; washdown; stainless or coated casing | Stainless Steel Evaporator |
Ripening | Banana and fruit ripening rooms | Controlled airflow and humidity; reversible | Ripening Air Cooler, Evaporator for Banana Ripening Room |
Powerless / unpowered | Natural-convection rooms | No fans; gravity coils | Powerless Air Cooler, Unpowered Air Cooler |
From our Cold Room Air Cooler and Blast Freezer Unit Cooler product pages:
Design: experienced engineers using advanced European design software, so capacity meets the demand accurately.
Refrigerants: R410A, CO2, ammonia, glycol and other special refrigerants.
Circuiting: direct oil return and counter-current heat exchange to avoid oil accumulation, use the whole surface and ensure superheat.
Tubes: multi-tooth internally grooved copper (copper purity above 99.9 %) for halocarbon and CO2 duty; stainless steel, aluminium, Cu-Ni, brass or titanium options; diameters from 5 mm to 25 mm; smooth, thick-walled, grooved or super-grooved.
Fins: aluminium, copper, stainless steel, titanium or hot-dip carbon steel; 0.1–2 mm; wave, flat or window (louvred) fin; E-coating, aluminium epoxy or hydrophilic coating.
Casing: 3003 aluminium alloy or galvanized steel (DC51-D+180 g) with high-temperature-cured outdoor paint; 304 stainless steel casing on stainless evaporators.
Fans: totally enclosed, high-efficiency external-rotor motors; blade-to-ring gap and hyperbolic air duct tuned for maximum throw.
Drain pan: double-wall insulated.
Applications listed: low-temperature blast freezing, blast tunnels and rooms, low-temperature test chambers, refrigerated ship holds, blast chilling, cold chain, carcass cooling and chilling rooms, cold rooms.
Room temperature and humidity target — sets the temperature difference (TD) between room air and refrigerant. Low TD for fresh produce (humidity); higher TD acceptable for frozen.
Cooling load — product load, transmission, infiltration, fans, lights, people, defrost.
Refrigerant — DX halocarbon, CO2, pumped ammonia or glycol; decides tube material and circuiting.
Room dimensions and racking — air throw and number of units.
Defrost method — electric, hot gas or water; frequency.
Hygiene requirements — stainless construction and washdown for food.
Mounting — ceiling, wall, floor; weight and height limits.
We return an evaporator drawing and selection sheet for approval before manufacture. Delivery is typically 20–30 days; one-year warranty after shipping; OEM logo available.
Yes. "Evaporator", "unit cooler", "air cooler" and "cold room evaporator" all describe the finned coil with fans inside the room.
Freezer coils frost heavily; wider fin spacing keeps airflow between defrosts. Chill rooms can use closer fins for more surface.
A heavy-duty evaporator with very high air velocity and wide fin spacing for freezing product fast at –35 to –45 °C.
Yes. Tube material and circuiting are chosen for the refrigerant; stainless or aluminium for ammonia, pressure-rated copper or stainless for CO2.
Both. Send a drawing, or send room data and load and we will select and draw the evaporator.
Send CSTHEATEXCHANGER your room temperature and size, cooling load, refrigerant, defrost preference and any hygiene requirements. We will select the evaporator type, size it and return a drawing for approval.
Email: info@cstheatexchanger.com
International business: +86 0519 8878 2189
Website: https://www.cstheatexchanger.com/
CSTHEATEXCHANGER — the evaporator is the only part of the system inside your cold room; we build it to match.
