One of the toughest problems energy-conservation programs face is verifying their accomplishments, which is particularly difficult in large, multi-building organizations where the savings produced by the implementation of a particular project get lost in the background noise of monthly energy-use variations.
Consider the energy use of a domestic-water booster pump system in a large health care facility. Most of these systems use constant-speed pumps to boost municipal water pressure to adequate levels for all areas within the facility. But the demand for water in health care facilities varies with the time of day and the activities taking place. With constant-speed pumps, the energy used to boost the pressure in the system does not vary much with water demand.
Installing variable-speed pumps does produce significant savings because the pump's energy use falls off rapidly with decreasing speed.
The problem for managers is verifying these savings. While significant, they rarely get noticed in the facility's bottom line, making it difficult for managers to obtain funding for additional energy projects. By installing submeters and tracking the system's performance before and after the conversion, managers can readily quantify the savings produced. Top management is more likely to provide additional funding if they have hard data on the success of past projects.
James Piper, P.E., is a national consultant based in Bowie, Md., with more than 25 years of experience with facilities management and maintenance issues.
Submetering: Taking Control of Power
Submetering Helps Managers Identify Savings Opportunities
Verifying Accomplishments Tough in Energy-Conservation Programs
Sidebar: Picking Candidates for Submetering