This paper discusses a supermarket environmental control system designed to reduce energy usage by a more efficient method of controlling store humidity. Tests have shown that the major source of humidity is the outdoor air introduced into the store.

The basic principle of design of this system is the removal of excess moisture from the outdoor air by passing it through a special dehumidification coil before this moisture enters the store and becomes a load on the refrigerated fixtures.

This paper gives a description of this system, an explanation of how it is controlled, and the benefits achieved. Key factors pertinent to system design and performance are illustrated by an example of a typical installation. Proof of energy savings is demonstrated by results of an actual field test conducted for this purpose.