Many facility owners are passing on the increasing cost of energy to their customers. However, as can be seen from the following case history, a retrofit based on a comprehensive energy audit can substantially reduce a facility's energy costs over the lifecycle of the equipment.
Originally, 10 direct expansion (DX) R-22 evaporators were installed in the facility. The initial design rated each evaporator at 11.5 TR when operating at a 10°F (5.6°C) air-to-evaporator temperature difference, for a total of 115 TR. When the refrigeration capacity proved to be inadequate, three more identical evaporators were added for a combined total refrigeration capacity of 149.5 TR. Again, the capacity was tested and did not meet the owner's required load. At the recommendation of the installing contractor, the owner agreed to adjust the air-to-evaporator temperature difference to 17°F (9.4°C). This adjustment increased the refrigeration capacity of evaporators to a total 254.2 TR. Each evaporator used 16.4 A of fan power, for a total of 148.5 kW, which equated to 0.58 kW/TR.