Laundromat, southern climate, tariff has an 80 percent ratchet on the highest demand in the preceding
11 months.
August 2023 the AC compressor and the water heater and a full floor of dryers all lined up on a 103
degree Saturday and set 94 kW. Normal months run 58 to 64 kW. So for the next 11 billing periods
they paid on 75.2 kW minimum regardless of what they actually used.
I calculated the ratchet cost at roughly 11,400 over the ratchet period. That is not an error and
there is nothing to recover, the tariff says what it says.
What I am putting in the report is prospective. If they can hold the summer peak under about 78 kW
they avoid the whole thing. Options are a demand controller that sheds the water heater when total
load approaches a setpoint, or moving the water heater recovery to a schedule.
Question for the group: on a load this small, does a demand controller ever pencil out? Every quote I
have seen is 8 to 14k installed and the vendors are all promising savings I cannot verify.
11 months.
August 2023 the AC compressor and the water heater and a full floor of dryers all lined up on a 103
degree Saturday and set 94 kW. Normal months run 58 to 64 kW. So for the next 11 billing periods
they paid on 75.2 kW minimum regardless of what they actually used.
I calculated the ratchet cost at roughly 11,400 over the ratchet period. That is not an error and
there is nothing to recover, the tariff says what it says.
What I am putting in the report is prospective. If they can hold the summer peak under about 78 kW
they avoid the whole thing. Options are a demand controller that sheds the water heater when total
load approaches a setpoint, or moving the water heater recovery to a schedule.
Question for the group: on a load this small, does a demand controller ever pencil out? Every quote I
have seen is 8 to 14k installed and the vendors are all promising savings I cannot verify.