A refrigeration system for use with refrigerated LT and MT display cases in facilities such as supermarkets, has an absorption chiller that uses waste heat from a nearby source to provide cooling to the refrigeration system to take advantage of the synergy and improve overall efficiency of the refrigeration system. The cooling provided by the absorption chiller may be in the form of a coolant (e.g. water, glycol, water-glycol mixture, etc.) that circulates between the chiller and one or more of a pre-cooler, sub-cooler or condenser in the refrigeration system in a manner that uses waste heat from a nearby source to reduce the need for installed condensing capacity in the refrigeration system and improve thermal efficiency and obtain cost savings.