Low temperature air conditioning system and method

Abstract

A low temperature air conditioning system provides primary air through smaller than normal ductwork and at a lower than normal temperature (such as 40.degree. F.) at peak load conditions. The primary air is mixed in branch ducts with return air taken from the conditioned space. Low pressure fans pull the return air into mixing boxes equipped with dampers which maintain the downstream temperature in the branch ducts at a normal supply air temperature (such as 55.degree. F.). Variable air volume terminal units discharge the air into the conditioned space. The small fans require only low horsepower and allow a smaller than normal central fan to be used. The cooling coil is cooled by a variable suction temperature refrigeration system which may be operated at night in conjunction with an ice storage system to minimize the demand for mechanical refrigeration during peak daytime hours. This arrangement permits the refrigeration machine to be smaller than normal and to consume less power during peak daytime hours.