Chillers often use water instead of refrigerant for several practical reasons:

1. Heat Transfer Efficiency

Water has a higher heat transfer efficiency compared to air. This makes it more effective at absorbing and removing heat from the refrigerant in a chiller system.

2. Cost and Availability

Water is generally less expensive and more readily available than specialized refrigerants. This can reduce the overall operational and maintenance costs of the chiller system.

3. System Design

Using water in the cooling process allows for the use of cooling towers or other heat rejection systems that can efficiently handle large amounts of heat. This design is particularly useful in large industrial applications.

4. Environmental Impact

The use of water can reduce the environmental impact compared to using refrigerants, which may have higher global warming potentials. Properly managed water systems can be more environmentally friendly.

5. Reduced Refrigerant Load

By using water to transfer heat, the amount of refrigerant needed in the system can be minimized. This can lead to more compact and efficient chiller designs.

6. Temperature Control

Water can maintain a stable temperature and provide consistent cooling, which is essential for processes that require precise temperature control.