Constant Load, Timed Schedule (CLTS)

CLTS includes equipment with constant load and constant hours-of-use, as depicted in Figure below. The degree to which a load or hours-of-use is constant may be defined by the user; ASHRAE’s Guideline 14-2002 indicates a 5% limit in the variance of load or hours-of-use to be considered constant. In this category, the measured energy use rate (kW) is often used directly in calculations, after verifying that the load is constant.

Examples of equipment with CLTS operating characteristics include:

1. Lighting under time-clock control

2. Constant volume air handling units under time-clock control (fan energy savings only)

3. Water treatment plant pump operation (24/7)

4. Constant-speed computer room air-handling unit fan operation (24/7)

5. Water fountain pumps

Source: BPA’s Verification by Equipment or End-Use Metering Protocol