Screw Compressors - First Cost

First cost of rotary screw chiller packages are generally about the same as centrifugals. Smaller sizes tend to be more expensive than their reciprocating counterparts. Screw compressors are gaining in popularity and the costs are expected to decrease as production increases. Operating Costs depend on the applicable electric rate and the chiller power input. Screw chiller packages typically have a lower power input than recips but use somewhat more power than a comparably sized centrifugal at ARI standard conditions. Air-cooled chillers typically have a higher full-load design kW/ton than water-cooled units. However, the operating profile of the facility has a major effect actual annual operating costs.

For example, an air-cooled chiller serving a hospital operating room that operates year-round could well have a lower annual electric cost than a comparable water-cooled unit, due to the large number of operating hours at part-load and low-ambient temperature conditions. A careful energy use and cost analysis performed by a professional will indicate the most economical choice.

Additionally, annual maintenance costs must be considered, and these costs tend to be about the same as the centrifugal counterpart.

If the chiller is driven by a natural gas engine, the added maintenance costs of the engine must also be added. Typically this annually amounts to about $0.012 ton per operating hour.

And Furthermore . . .