Page 208 - WaterSense at Work

October 2012
University of Massachusetts Amherst, CEERE, IAC,
op. cit
op. cit
Energy Design Resources. December 2009.
Chilled Water Plant Design Guide
op. cit
other system component performance should be evaluated prior to performing the
retrofit. By using University of Massachusetts Amherst Center for Energy Efficiency
Renewable Energy’s ChilledWater Systems Analysis Tool,
facility managers can
evaluate which of the following retrofit options are the best.
Water-Related Retrofits
For retrofit options that involve water reduction, consider the following:
Install a make-up water meter on the chilled water loop, which will allow for leaks
to be easily identified.
Insulate the pipes on the chilled water loop to ensure that the chilled water does
not absorb unnecessary heat, therefore requiring more water to cool.
Energy-Related Retrofits
In addition retrofit opportunities to increase the water efficiency of a chilled water sys-
tem are in many cases directly related to reducing energy use by reducing the overall
cooling load on the system. Consider the following energy-related retrofits in addition
to the retrofit options discussed in University of Massachusetts Amherst’s ChilledWater
Systems Analysis Tool. For additional information on increasing the energy efficiency
of existing chilled water systems, review Energy Design Resources’
ChilledWater Plant
Design Guide
and the U.S. Environmental Protection Agency (EPA) and U.S. Energy
Department’s (DOE’s) ENERGY STAR®
Building Upgrade Manual
Replacing Pump Valves
Standard valves can be replaced with low-friction valves to reduce flow resis-
tance in the chilled water loop, thereby reducing pump energy use.
For valves that control flow by inducing a pressure drop, consider removing the
valves or eliminating their use by keeping the valve open. These types of valves
can be replaced by using variable-speed controls, trimming the impeller, or stag-
ing pumps instead.
Replacing Pumps
Standard or oversized pumps can be replaced with more efficient pumps. Pumps
typically reach peak efficiency when they are approximately 75 percent loaded,
but they are less effective if they are fully or under loaded.
Chilled Water Systems