In an attempt to do a comparative performance benefit based on similar chiller price, the base efficiency of the constant-speed chiller was improved by 10% by taking the additional dollars spent on a variable-speed drive and applying it to improve the design performance for the constant-speed unit
(generally in the form of more effective heat exchangers).
Electric motors have high power-to-weight ratios and, when sized properly, can provide sufficient torque over a wide speed range to replace a multi-speed transmission with a simple constant-speed unit
. At their most basic, series hybrids use the combustion engine to drive a starter-generator that provides power to the electric motor(s).
The equipment also requires more room within the station, and may produce more noise than a constant-speed unit
. Once the station type, flow requirements, and type of pump have been established, a number of pump station accessories must be considered.