Refrigeration equipment is the core component of a cold storage system, directly determining cooling efficiency, temperature stability, energy costs, and the quality of stored goods. It is also crucial for preventing frost buildup, cold air leakage, excessive electricity consumption, and product spoilage.
When selecting cold storage equipment, we cannot solely focus on price, neglecting factors such as storage capacity, temperature conditions, heat exchange configuration, and environmental adaptability. Otherwise, problems such as frequent equipment start-ups and shutdowns, insufficient cooling, high annual electricity bills, and high equipment failure rates may arise.
Based on years of industry experience, Element has compiled a set of refrigeration equipment selection methods suitable for small and medium-sized commercial cold storage, large cold chain cold storage, low-temperature quick-freezing cold storage, and pharmaceutical constant-temperature cold storage.
I Clarifying the Basic Core Parameters of Cold Storage
The models, cooling capacities, and configurations of all refrigeration equipment are not interchangeable; they must be customized based on the actual operating conditions of the cold storage. This is the core prerequisite for avoiding selection errors. Four core parameters are indispensable:
1. Cold Storage Temperature Settings
Different storage categories correspond to specific temperature ranges. Temperature conditions directly determine the equipment type, refrigerant configuration, and low-temperature performance of the unit. The industry-standard classifications are as follows:
- High-Temperature Cold Storage (0℃～10℃): Suitable for fruits and vegetables, fresh produce, flowers, and room-temperature pre-cooled foods. Primarily focused on constant temperature preservation, with lower requirements for cooling speed; key focus is on temperature and humidity control.
- Medium-Temperature Cold Storage (-18℃～0℃): Suitable for frozen meats, dairy products, semi-finished ingredients, and quick-frozen prepared foods. This is the most commonly used type of commercial cold storage, requiring high temperature stability.
- Low-Temperature Cold Storage (-35℃～-20℃): Suitable for deep-sea seafood, frozen beef and mutton, and bulk quick-frozen goods. Requires large-capacity units to support rapid cooling and freshness preservation.
- Ultra-Low-Temperature Cold Storage (below -35℃): Suitable for high-end seafood, biopharmaceutical reagents, and special cold chain materials. Requires dedicated low-temperature units and is suitable for extremely low-load operating conditions.
II. Accurate Calculation of Cooling Capacity
Envelope Heat Leakage Heat transfers through insulated wall, ceiling and floor panels. Formula: Q1 = K × A × Δt K‑thermal conductivity of PU/PIR panel; A‑total surface area; Δt‑temperature difference between ambient and inside cold room.
Product Heat Load Heat brought in by incoming goods, including sensible heat for temperature drop and latent heat for product freezing. Daily incoming weight, initial product temperature and specific heat shall be considered.
Air‑exchange Ventilation Load Mainly for fresh‑produce cold rooms. Heat and moisture enter through door opening and staff access. This item can be ignored for deep‑freeze warehouses.
Operational Heat Load Heat generated by evaporator fans, interior lighting, forklifts and working personnel.
Add up all four heat values, then multiply by a safety factor of 1.1 ~ 1.3 to get final required refrigeration capacity for unit selection.
Quick‑estimation reference for small‑medium prefab cold rooms:
Chiller cold room (0~+5℃): 70‑100 W/m³
Refrigerated cold room (-5~0℃): 100‑130 W/m³
Standard freezer (-18℃): 130‑180 W/m³
Ultra‑low temp freezer (-25~‑30℃): 180‑250 W/m³
III. Core Equipment Selection: Compressor, Evaporator, and Condenser Combination Scheme
Compressors define unit stability, power consumption and service life. Scroll compressors work best for small‑size medium‑high temperature cold rooms for fruits and fresh food. Semi‑hermetic reciprocating compressors feature wide temperature ranges and are widely used for meat and seafood freezing projects. Screw compressors support 24‑hour continuous heavy‑load operation for medium‑large logistics cold storage. Parallel compressor units adjust capacity dynamically and are preferred for large multi‑temperature‑zone cold‑chain warehouses.
For evaporators, coil‑type air coolers provide fast, uniform cooling with multiple defrost choices for general food cold rooms. Fan‑coil evaporators generate gentle airflow to reduce goods dehydration, ideal for frozen meat and moisture‑sensitive dry goods.
Two main condenser types are available. Air‑cooled condensers need no water supply and remain the mainstream for most commercial cold‑storage sites. Water‑cooled condensers offer higher heat‑exchange efficiency and strong high‑temperature resistance for large‑scale hot‑climate projects, yet they require cooling towers and circulating water systems.
IV. Refrigerant Selection: Compliant, Efficient, and Suitable for Operating Conditions
Refrigerants directly affect refrigeration efficiency, environmental compliance, and equipment compatibility. Indiscriminate mixing is prohibited. Industry-standard compliant solutions include:
- R134a: Suitable for high-temperature preservation cold storage, environmentally friendly, and stable operation. Primarily used for constant-temperature storage of fruits, vegetables, and flowers.
- R404A / R507: Mainstream refrigerants for medium- and low-temperature cold storage, strong refrigeration effect, and high stability. Suitable for freezing and low-temperature quick-freezing cold storage facilities.
