Refrigeration Chillers continue to become more and more efficient. However, it is truly difficult to compete with something as simple as a basic dry cooler (air over heat exchanger) when it comes to energy consumption. In cooler climates where the ambient temperatures drop below freezing during the winter months, dry coolers can provide a very inexpensive means of cooling your process.
There are two types of free cooling systems. One features an evaporative cooling tower, heat exchanger, and cooling tower pump. The second system utilizes a dry cooler. Both have advantages but we are going to focus on the dry cooling system in this post.
To highlight the major benefit of a free cooling system, let’s consider a nominal 50HP process cooling application. In this process, your typical air cooled chiller will require 50-60HP of compressor to achieve your desired capacity (at 45F leaving fluid temperature). In comparison, a dry cooler can deliver your same capacity with just 5 fans (or 10HP). That’s a 40HP difference at minimum! These values are approximate, but if there is an 80% reduction in HP, the kW/ton will drop similarly. Anyone would like to see that kind of energy savings at their plant, correct? The other positive about dry coolers is that they are a closed loop system. With a closed loop system, you don’t have to be concerned with airborne contaminants entering your cooling system – like you would with an open loop cooling tower system. A water treatment package is not required for a dry cooler, free cooling system. In most applications, you can use your chiller pump to deliver the process fluid (glycol/water mix recommended) to your dry cooler. The chiller pump diverts the process fluid to the dry cooler with the help of a diverting valve.
As you can see, it is a fairly simplistic system and yet provides quite a valuable savings. If you have an application where you may be able to use a dry cooler or free cooling system, please feel free to contact us. We’re always happy to help. You can reach us at 281.540.2805 or SmartCoolingProducts Website.