While searching for a way to cool concrete and still make a profit, Hodgson Concrete Company of Montgomery, Alabama learned about a water-source pump that controls batch water temperature to either cool or heat concrete. The same system could be used to cool batch water to 35 degrees in the summer and heat it to 140 degrees in the winter. Groundwater is usually the heat pump's primary energy source, but the system can use any other water source, such as a lake, river, or utility. If water isn't easily accessible, a heat pump is available that uses air as the primary energy source. A solid-state computer controls the system automatically without supervision. Because the system is modular, if one module fails, the other modules still operate so heating or cooling isn't interrupted. Use of this heat pump on a large hospital expansion project resulted in an annual savings of 43,930 dollars and 78 cents over the use of liquid nitrogen and a gas boiler.