In order that there may be adequate air circulation within the refrigerated space, the ice should be located near the top of the refrigerator and proper baffling should be installed to provide direct and unrestricted paths of air flow. To collect water which results from the melting, a drip pan must be located beneath the ice.
Ice entails certain disadvantages which tend to limits its usefulness as a refrigerant. These are as follows:
1. There is necessity of frequently replenishing the supply: a practice which is neither convenient nor economical. In addition there is a problem of disposing of water resulting from the melting.
2. A difficulty is experienced in controlling the rate of refrigeration, which in turn makes it difficult to maintain the desired low temperature level within the refrigerated space.
3. With ice it is not possible to obtain low temperatures required in many refrigeration applications. Ordinarily, 0°C is the minimum temperature obtainable through the melting of ice alone. In some cases, the inlet temperature of ice can be lowered to approximately — 18°C by adding sodium chloride or calcium chloride to produce a freezing mixture.
Inspite of the fact ice has several disadvantages, ice is preferable to mechanical refrigeration in some applications:
1. Fresh vegetables, fish and poultry are often packed and shipped in cracked ice to prevent dehydration and to preserve appearance.
2.Ice has tremendous eye appeal and can be used to considerable advantages in the displaying and serving of certain foods such as salads, cocktails, etc. and in chilling beverages.