What is the difference between air-cooled and water-cooled condensing units?

Differences between air-cooled and water-cooled condensing units

1. Different heat dissipation media
Air-cooled units use air as the heat dissipation medium, using fans to dissipate heat directly into the ambient air. Water-cooled units use circulating or cooling water, removing heat through a cooling tower or condenser pump.

2. Difference in heat exchange efficiency
Water has a much higher specific heat capacity than air. Water-cooled units have higher heat exchange efficiency for the same power output, enabling lower condensing temperatures and more compact unit sizes. Air-cooled units, on the other hand, are limited by ambient temperature and air volume, resulting in relatively lower heat exchange efficiency.

3. Installation and site requirements
Air-cooled units have a relatively simple structure, requiring only ventilation space and power supply, making them suitable for locations with limited space or no water supply. Water-cooled units require a corresponding water pump, piping, and cooling tower, placing higher demands on the site's water supply, drainage, and maintenance conditions. 4. Operating Costs and Maintenance
The operating costs of air-cooled units are primarily electricity, and maintenance is relatively simple. While water-cooled units can significantly reduce energy consumption under high loads or high temperatures, they require regular cleaning of the cooling tower and water quality inspections, resulting in higher maintenance costs.

How to select the appropriate condensing unit capacity based on cooling needs?

Selecting the appropriate condensing unit capacity based on cooling needs

1. Determine the cooling load

Calculate the required cooling capacity (kW) based on the process or storage requirements. Common methods include heat load calculations, empirical coefficients, or the cooling capacity determination formula in the national standard GB/T21363-2018.

2. Select the operating conditions

Determine operating parameters such as ambient temperature, inlet air temperature, and evaporating temperature. Select the corresponding selection conditions (e.g., 38°C ambient temperature, 27°C ambient temperature), and refer to the manufacturer's selection table for matching.

3. Match Cooling Capacity with Unit Capacity
Compare the calculated cooling load with the unit's rated cooling capacity. Ensure the unit's rated cooling capacity is slightly higher than the actual demand, generally leaving a 5%–10% margin to ensure safe and efficient operation.
4. Consider Energy Efficiency and Operating Mode
Evaluate the unit's COP (Cost Effectiveness Ratio) and variable/fixed frequency characteristics, prioritizing variable frequency units to accommodate load fluctuations. Also, comprehensively compare the energy efficiency indicators of different models based on the project's energy consumption targets.