Being located in the cold climate of New England, we often witness manufacturers who run expensive chillers in an attempt to cool fluids to 50°—when its 30° outside! It’s analogous to using an air conditioner on a cool day instead of opening a window. Even in an industrial application, it's more efficient and effective to let Mother Nature do the cooling for you.
It's important to note that this cannot be accomplished in a warmer climate, and the return on investment won’t be there for limited- use applications. However, if you have a steady cooling load year-round, there are many free initiatives that offer attractive payback.
First and foremost, adding dry free cooling with a radiator is simple and effective. The radiator produces the same cooling as a chiller at only 5% the cost! One caution: you cannot send water or anything else that can freeze outside to the radiator. When the system is down, the fluid can freeze and ruin the radiator. If a non freezing fluid like glycol cannot be used, use an intermediate heat exchanger. You may lose a few degrees and potentially could have to add another pump but it will often produce savings similar to those mentioned above.
A favorite recommendation of ours is evaporative free cooling, which offers as much as 25% more free cooling hours per year in comparison to dry free cooling.
A great trick for gaining additional free cooling efficiency is partial free cooling, which initiates free cooling based on the warmer return temperature. With either dry or evaporative you can add as much as 25% more hours. This will save an average of 50% of the energy during these partial free cooling hours.
Free cooling is a crucial topic for energy efficient facilities. We'd love to read your comments. You may also e-mail questions or potential blog topics to firstname.lastname@example.org.