Refrigeration Load Considerations General The designer must consider all aspects of the load, including all items contributing to it, to properly design the refrigeration system. The following factors must be considered (even though they may not be involved in the final load): Heat leakage (in the form of latent and sensible heat) flowing into the space or product to be refrigerated, Product load: the heat that must be extracted to change the product's initial temperature to the desired end temperature, including pull-down time allowable, and the Internal sensible load: results from motors, lights and other heat-generating equipment in the conditioned space impacting the refrigeration load. Pull-down time is the length of time it takes to change all of the product's temperature from the initial temperature going into the refrigerator to the desired end temperature. If the pull-down time is too long, some spoilage or discoloration can occur. Excessively short pull-down times waste energy as the refrigerant's evaporating temperature is lower than it needs to be. Process refrigeration loads, while influenced to a certain degree by these same factors, are dictated mainly by production requirements (unless thermal storage techniques are used).