What I installed for one customer is a controller with 2 setpoints and a time clock.
Normally the set point for the tank is 3 deg C.
In order to make use of the low cost night electricity @ 5 am the new controller gets a signal from the time clock to change over to the second set point which is set at 0 deg C.
This cools the milk to the lower set point at the cheep electricity before the farmer starts milking. This will reduce the amount of electricity required to cool the morning milking to the required 3 dec C.
This could also be used to ensure that the temperature in the tank is with in specification if collection is scheduled vey soon after the end of milking.
Normally the set point for the tank is 3 deg C.
In order to make use of the low cost night electricity @ 5 am the new controller gets a signal from the time clock to change over to the second set point which is set at 0 deg C.
This cools the milk to the lower set point at the cheep electricity before the farmer starts milking. This will reduce the amount of electricity required to cool the morning milking to the required 3 dec C.
This could also be used to ensure that the temperature in the tank is with in specification if collection is scheduled vey soon after the end of milking.