Refrigeration capacity is not one fixed number. It changes with room setpoint, evaporating temperature and ambient conditions.
In short: compare units at the same design point. A model suitable for a chiller may have much less capacity at freezer conditions.
Positive-temperature rooms commonly use medium-back-pressure duty, while freezers use low-back-pressure duty. These are compressor operating categories, not exact room-temperature labels.
When checking a data sheet, confirm:
- refrigerant and electrical supply;
- cooling capacity at design conditions;
- highest allowed ambient temperature;
- line-length limits;
- defrost method;
- minimum and maximum room volume or load stated by the manufacturer.
Do not select from floor area or nominal horsepower alone.
Planning bands
| Class | Cooling capacity | Room volume | Target temperature |
|---|---|---|---|
| Small chiller | 0.5 – 1.5 kW | 3 – 10 m³ | 0 °C to +10 °C (food typically ≤ +5 °C) |
| Medium chiller | 1.5 – 3.5 kW | 10 – 25 m³ | 0 °C to +10 °C (food typically ≤ +5 °C) |
| Large chiller | 3.5 – 7.0 kW | 25 – 50 m³ | 0 °C to +10 °C (food typically ≤ +5 °C) |
| Small freezer | 0.5 – 1.0 kW | 2 – 6 m³ | −18 °C to −22 °C |
| Medium freezer | 1.0 – 2.5 kW | 6 – 15 m³ | −18 °C to −22 °C |
The figures above are indicative. Chilled "≤ 5 °C" is typical best practice with some national variation; frozen −18 °C is the firm food-safety reference. Always confirm against a proper heat-load calculation before ordering.
Why class matters
Chillers operate at medium evaporating temperatures (MT) and freezers at low evaporating temperatures (LT). The evaporating temperature, not just the kW figure, defines what setpoint a unit can hold — so a chiller-class unit will never pull a room down to a freezer setpoint, regardless of how it is controlled.
Frostbox / Daikin reality: The units Frostbox supplies are Daikin condensing units and monoblocks, selected by family rather than by generic "small/medium/large" labels. Typical families include GS and SP-O (quick-connect, plug-and-play range), and DB-O, RDV, SAS/SAR for standard split distances, alongside Daikin monoblocks. The configurator matches the right family to your room, temperature, and the distance to the condenser; ask for the model datasheet — available on request — for exact capacities and refrigerant.
Related articles
- Monoblock vs split: which to choose
- Monoblock systems explained
- Split systems explained
- Refrigerants and F-gas compliance
- Heat load calculation
- Using the Frostbox size calculator
Specifications reflect the Daikin refrigeration units supplied by Frostbox on MTH Algor cold rooms. Exact model capacities are available on request — contact [email protected].
