Client converted from coin to a card system last spring, which came with new control boards and
variable frequency drives on a portion of the washer fleet. Consumption dropped 18 percent
year over year, verified against degree days, and the operator is happy.
Billed demand is identical. Not close, identical to within a kW in most months.
Pulled the interval data and I think I understand why but I want a second opinion. The VFDs are
smoothing the ramp on individual machines, but the peak is not being set by any single machine. It
is set by the coincidence of the water heater recovery cycle with the dryer bank, and that
coincidence is unchanged because it is driven by customer arrival patterns, not by machine
efficiency.
If that is right, the client bought a real energy saving and zero demand saving, and the demand
portion is roughly 40 percent of the bill. The lesson I am taking is that efficiency retrofits sold
on kWh should be evaluated against the demand component separately before anyone signs. Curious
whether others have seen the same pattern in laundry.
variable frequency drives on a portion of the washer fleet. Consumption dropped 18 percent
year over year, verified against degree days, and the operator is happy.
Billed demand is identical. Not close, identical to within a kW in most months.
Pulled the interval data and I think I understand why but I want a second opinion. The VFDs are
smoothing the ramp on individual machines, but the peak is not being set by any single machine. It
is set by the coincidence of the water heater recovery cycle with the dryer bank, and that
coincidence is unchanged because it is driven by customer arrival patterns, not by machine
efficiency.
If that is right, the client bought a real energy saving and zero demand saving, and the demand
portion is roughly 40 percent of the bill. The lesson I am taking is that efficiency retrofits sold
on kWh should be evaluated against the demand component separately before anyone signs. Curious
whether others have seen the same pattern in laundry.