Seasons 4 - Commercial Heating and Cooling System Manufacturers

One of the most important factors in refrigerated display case operating efficiency is control of the store humidity. The equipment used to display product utilizes medium and low temperature refrigeration, which is highly sensitive to humidity levels in the supermarket. If humidity levels are high more defrost cycles are required to keep display case evaporators free of frost and ice build-up. The build up of frost and ice on coil surfaces adversely effects product integrity and energy usage.

Refrigerated case operating costs represent over 50% of the store’s utility bills. A department of energy study showed that 75% of refrigeration load is directly related to the store environment. Figure 1 demonstrates the effect of store humidity on refrigeration case load, and operating cost is a direct function of the store humidity.

Maintaining low moisture levels in a supermarket lowers refrigeration operating costs thus reducing total store energy costs.

In supermarket HVAC design, because of store size and the accompanying case credits to the cooling load, it is usually found that the amount of air flow required to adequately condition the sales area is more than is needed for the tonnage required.

If all of this air is conditioned and the sensible load requirement of the store is met then, because of the resulting low cooling coil TD, the latent (or dehumidifying) capacity of the unit is inadequate. The result would be a store that is maintained at the desired temperature with very poor humidity control; a condition that is not only detrimental to customer comfort but also to display case operating economy.

By addressing humidity control and providing a system to maintain lower than normal humidity, the temperature can be kept at more comfortable levels and refrigeration operating economy is increased. Consult the Seasons•4 sales staff for application assistance with your store HVAC designs.