Covering the simultaneous needs for cooling and heating in supermarkets by a proper utilization of vapour compression systems is an interesting possibility for significant energy savings. This is a major issue considering supermarket refrigeration systems consume a large amount of energy. The environmental concerns and regulations attached to refrigeration applications forced the implementation of new system solutions where natural refrigerants have been widely used. This book includes an analytic comparison of conventional supermarket refrigeration systems using R404A with refrigeration system solutions using natural refrigerants such as carbon dioxide and ammonia. This investigation points out the fact that systems running with natural refrigerants can compete with systems running with artificial refrigerants by using adequat heat recovery systems such as heat pump cascade, heat pump cascade for sub-cooling, fixed pressure system and de-superheater.