Choosing the right chiller size can be challenging. Various factors influence chiller performance, including:
Some applications may also have specific cooling time requirements or flow rates that need consideration.
A common mistake is underestimating the heat being added to the water. When asked about the heat load, many respond with “not much.” This answer is not helpful. To estimate heat load accurately, bring your system to the desired temperature using ice or another method. Remove all the ice and measure how quickly the water heats up. Knowing the volume of water and the time it takes to change temperature allows you to calculate an estimated heat load. (See our article on BTU for more details.) While it’s still an estimate, it’s far better than guessing.
It’s nearly impossible to oversize a chiller for your project. The rule of thumb is: when in doubt, go with the next size up. Extra cooling power is always beneficial. A larger chiller does not necessarily use more electricity than a smaller one. In fact, a bigger chiller runs less often, using roughly the same amount of electricity to perform the required work.
An undersized chiller will struggle to reach your desired temperature, running more frequently and consuming more energy in the long run. Conversely, a larger chiller, running less often, tends to have a longer lifespan. Therefore, opting for a slightly larger chiller can be a safer and more efficient choice.
In summary, when sizing a chiller, consider all factors, including volume, heat inputs, ambient temperatures, and goal temperature. Estimating your heat load accurately is crucial. Remember, it’s better to have a chiller that is slightly too large than one that is too small. A larger chiller will not only meet your cooling needs more efficiently but also last longer and provide better overall performance.
