Account for system effects when comparing chillers. Although it is tempting to improve the efficiency of chilled water systems by minimizing the energy consumption of each individual component, that approach does not necessarily lead to the most efficient system. The pieces of a chilled water system interact in complex ways that make such general prescriptions difficult. For example, although the efficiency of a chiller can be improved by increasing chilled water flow, that will require more pumping power, which may exceed the saved chiller power and result in a net loss of system efficiency. Select unequally sized machines for multiple chiller installations.
Chillers operate more efficiently when they are loaded close to their full rating.
If one chiller in a two-machine installation is smaller than the other, under most operating conditions, one of the two chillers should be able to handle the job running close to full load. Having the option of switching between plants with different capacities will result in more efficient operation than if one or two same-sized chillers were operating at a lighter load. The prototypes are using cylinders of the rare-earth metal gadolinium, along with a superconducting magnet. Magnetocaloric chillers have the potential to be highly efficient, but currently they are much more expensive than vapor-compression chillers. Research is underway to reduce the cost of chillers based on this novel technology.