Reducing energy consumption is a crucial component of our global effort to reduce carbon emissions. The more efficient we can make our processes, the lower our carbon output and the more sustainable we become.
In industry, there is not one golden rule to reduce consumption, rather it's a combination of multiple small wins, that when combined, create a system that is much more economically and environmentally friendly.
Any industry that requires a cooling process can benefit from more sustainable cooling, such as free cooling.
What is free cooling?
Free cooling uses low external air temperatures to assist in cooling water for industrial temperature control applications or in HVAC systems.,
How does free cooling work?
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 to the circuit.
When the ambient air temperature drops just 1°C below the process fluid return temperature, a 3-way valve diverts the returning process fluid through the free cooling coil in which the cooler ambient air removes process heat and cools the returning fluid (partial free cooling), it then flows through the chiller's evaporator where the required set point temperatures are achieved – easing the demand on your chiller's components and extending their operational life.
As the ambient air temperature continues to fall, the amount of process heat taken out of the process fluid by the air increases, progressively reducing the load on the chiller. At 5°C below the process supply fluid temperature, all the process heat is removed by the ambient air in the free cooler – providing full free cooling.
Type of free cooling
A standalone free cooling system sees an independent free cooling unit working alongside an electro-mechanical chiller.
As the system comprises at least two units, it requires a greater amount of space given the footprint of the equipment, and the subsequent need to allow air to circulate around the units. However, the increased footprint means a larger surface area, which can allow better part loading to be achieved – akin to an 80% saving on running costs a year.
What's more, standalone free cooling systems have the capacity to provide 100% free cooling at a higher ambient air temperature than integrated free cooling chillers. From a cap-ex perspective, a standalone free cooling system can work alongside an existing chiller.
As such, start-up costs can be lower as the original chiller can remain in service.
Integrated free cooling units are a viable option for sites which may not have the available floor space to accommodate standalone units.
It is ideal for high capacity systems with limited available footprint, as a standalone system on that scale would require significant floorspace to accommodate the necessary equipment.
However, for an integrated system to achieve 100% free cooling, the ambient air temperature needs to be lower; usually in the region of 2°C, compared to 5°C for standalone systems.
Do I require a new chiller for free cooling to work?
Free cooling works with either a chiller with a built-in free cooling coil or a free cooler working in series with a chiller. The latter is more efficient, due to the larger surface area provided by the air cooler and we are able to offer both options.
A remote free cooler is designed to do nothing but provide free cooling and has its own purpose built control system, a 3-way valve and bypass system. Therefore it is a simple and reliable way to give maximum savings and quick payback.
As the system is fully packaged, complete with integral controls, 3-way valve & actuator and bypass pipe work, they can be easily installed on existing systems as well as new builds.
No communication between the free cooler and chiller is necessary. In typical process cooling systems, chillers can be offloaded for up to 90% of the year.