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Quotes - Engineering - SalesWater-Side Economizer
Free Cooling Without the Chillers
A water-side economizer places a heat exchanger between the tower water and the chilled water loop. When conditions allow, the tower does all the work and the chillers shut down, removing the largest electrical load in most buildings.
Approach buys hours. Every degree of approach raises the outdoor condition at which free cooling starts. A plate exchanger reaching within two or three degrees delivers far more annual hours than any wider-approach alternative.
Size for the shoulder season. The economizer is not sized on design day; it is sized for the conditions where it will actually run. Getting that wrong produces an exchanger that only works on the coldest week of the year.
Partial free cooling. Even when the tower cannot meet the whole load it can pre-cool the return, reducing chiller work. Designing for partial operation extends the benefit across far more of the year.
Typical Specification
- Application: Chiller-free and partial free cooling
- Key metric: Approach temperature
- Sizing basis: Shoulder season conditions, not design day
- Partial mode: Pre-cools return water when full free cooling is unavailable
- Tower side: Open water; plate material selected for chemistry
- Chilled side: Closed loop
- Control: Changeover and staging designed with the exchanger
- Footprint: Small; fits existing plant rooms
- Cleaning: Tower side opens for periodic service
- Saving: Chiller electrical load removed during free cooling hours
Common FAQs
It depends on climate, chilled water temperature and the exchanger approach. The approach is the part you control, and a closer approach converts directly into more hours per year.
No. Size for the shoulder season conditions where free cooling will actually operate. An economizer sized on design day is usually far too small to be useful for most of the year.
Using the tower to pre-cool the return water even when it cannot meet the whole load, so the chiller does less work. It extends the benefit across a much larger part of the year.
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