Possibilities of pre-heating water with the heat obtained by cooling milk in a wet-tank milk cooler
The following conclusions appear to have merit:
The heat obtained from cooling milk in a mechanical farm milk cooler may be used for preheating a quantity of water.
The amount of water heated and the temperature to which it is heated are functions of the heat obtainable from the milk cooler and refrigeration equipment.
The percentage of available heat from the condenser that is available in the water passed to the electric water heater is a function of: (a) the design of the condenser-to-water heat transfer system, (b) the size and shape of the storage tank, and (c) the losses from the storage tank.
The savings in cost of electric energy for operation of the electric water heater are appreciable when heat extracted from cooling milk is used to pre-heat water. In this study, the savings amounted to slightly more than 30 percent. However, a large quantity of heated water passed to the overflow tank. A savings of 54 percent could be realized when the water drawn from the pre-heat tank into the water heater was raised from 62 F - 120 F in the pre-heat tank.
Without the assistance of a competent refrigeration mechanic, the technical problems involved make it inadvisable for the individual farmer to attempt a conversion of current milk cooling equipment for the additional function of heating water.
This study indicates that greater savings may be effected with a refrigeration unit and condensing unit specifically designed for heating water, using the basic principles outlined in this study.