The most common mistake I see these days is how chiller plant owners and/or consulting engineers operate their plants the same way they have for the past 25-30 years. While this is almost always based on good engineering data, the data is, unfortunately, based on 25-30 year old products and practices. And, since the typical lifespan of a chiller is 25 years, owners may never have had to purchase new equipment so they don’t realize the new improvements available. The fact is, new technologies exist that can greatly reduce the energy used by chillers and chiller plants.
First, the cooling tower has been used for over 50 years with chiller plants and there have been some improvements to that product, but the main item missed by the owner/consultant is the temperature setpoint of the tower. 25 years ago the generally accepted setpoint was 75°F due to the fact that most of the chillers of the time couldn’t operate with colder tower water temperatures. Today’s chillers can use much colder temperatures, some as low at 50°F, and taking advantage of this capability can save significant dollars. The lower the tower water temperature the less work the chiller compressor has to do and the less energy is used.