To select an evaporative condenser for cold storage, start with the refrigerant, the total heat of rejection and the design condensing and outdoor wet-bulb temperatures. These inputs define the duty the condenser must meet during the site’s design conditions.
Calculate total heat of rejection
Use the compressor or refrigeration package manufacturer’s heat-rejection data at the intended evaporating and condensing conditions. As a preliminary example, if the evaporator removes 400 kW and 100 kW of compressor input reaches the refrigerant, the condenser must reject about 500 kW. If the system rejects some compressor heat through a separate oil cooler, use the manufacturer’s heat balance to confirm the condenser duty.
Specify condensing temperature and design wet-bulb
Condensing temperature is a refrigerant-side selection input. Entering-air wet-bulb is the outdoor selection input for evaporative heat rejection. For example, specifying 35°C condensing and 27°C entering wet-bulb gives an 8°C difference for the stated design point. Request a model selection at both conditions. A tighter difference can require a larger unit, and warmer air recirculating into the inlet can reduce available capacity.
For ammonia systems, include refrigerant pressure, material requirements and the project design basis. If the refrigeration system uses transcritical CO₂, confirm whether the heat-rejection equipment needs to be selected as a gas cooler.
Check seasonal operation and maintenance
- Load profile. Include normal storage loads, pull-down peaks, freezer duty and the required capacity with a unit out of service, where applicable.
- Airflow and access. Check nearby walls and other heat-rejection equipment. Leave space to inspect spray nozzles, drift eliminators, fans and the coil.
- Water program. Provide makeup-water analysis and availability. Confirm water treatment, blowdown and winter operating provisions with the project team.
- Replacement work. Record foundation dimensions, refrigerant piping connections, unit weight, lifting access and the available shutdown window.
What to send for a condenser selection
Send the refrigerant, peak total heat rejection, condensing temperature, design wet-bulb, site elevation, water analysis, available space and sound limits. For a replacement, include drawings or photographs of the existing equipment and piping.
Compare HACST evaporative condenser models, see the Australian food-processing project, or request a project-specific selection.
