Free Cooling Explained
Free Cooling is a fast and effective, economic method of utilising low external air temperatures. It can be used to assist in cooling water for industrial temperature control applications or in HVAC systems.
A chillers’ traditional design utilises integral compressor technology to generate the cooling required for process and HVAC applications.
The use of Free Cooling in an industrial temperature control application differs from an environmental cooling solution as fresh ambient air cannot be drawn straight into the cooling circuit. Therefore, to harness the benefits of the low ambient temperatures a Free Cooling coil needs to be introduced into the circuit.
A Free Cooling coil is installed in series with the chiller system’s evaporator so in lower ambient conditions, partial or 100%, Free Cooling can be achieved. This method of operation, utilises the UK’s natural low ambient temperatures and in doing so benefits from a reduction in energy costs of up to 70%.
As the ambient air temperature drops at least a degree below the process return water temperature, the benefits of Free Cooling can begin to be realised and the external ambient temperature can begin to cool a process in place of a chiller. As the ambient temperature drops 3 oC to 5oC below the required process supply water temperature total Free Cooling can be achieved taking over from the chillers’ compressors 100% and consequently providing an environmentally friendly and cost effective approach to process and HVAC cooling.
- Independent Free Cooler
- Integral Free Cooler
As a leading supplier of temperature control solutions ICS Cool Energy is able to offer Free Cooling systems for both sale and hire to ensure customers achieve the greatest energy savings to suit their business and application requirements.
When the process return water temperature required is equal to or higher than the ambient air temperature Free Cooling is not suitable. The system’s three way valve will continue to direct the fluid flow through the chillers’ compressors to be cooled to the required set point temperature.
Mid season operation
For mid-season operation the water is partially cooled by the compressor and partially by the ambient temperatures. The percentage of Free Cooling achieved mid-season is dependent on seasonal temperatures although partial Free Cooling commences when the ambient air temperature is 1oC below the process return water temperature. The water is partially cooled through the Free Cooler then flows through the chillers’ compressors to achieve the required set point temperature.
In winter, when outdoor temperatures are low enough, the water is chilled solely by the Free Cooling coil. This allows the chillers’ compressors to stop operating, saving significant amounts of energy. The only electrical power used in winter operation is for fan operation. This can be achieved once the ambient air temperature is 3oC – 5oC below the process supply water temperature.