Patent ID: 6948325

Claim:
An air conditioning system for conditioning a supply of hot pressurised air for use in an environment, the system including a primary heat exchanger in which heat in the hot pressurised air supply is exchanged with a cooling fluid, a compressor to compress the supply of pressurised air cooled in the primary heat exchanger, a secondary heat exchanger in which heat in the compressed air supply is exchanged with a cooling fluid, and an expansion device for expanding and cooling the compressed air supply cooled in the secondary heat exchanger, mixing apparatus for mixing the expanded and cold supply air with recirculating air from the environment, a by-pass flow path for compressed cooled supply air from the secondary heat exchanger to the environment, and a secondary supply flow path for the hot pressurised air to the secondary heat exchanger, a first valve in a primary supply flow path to the primary heat exchanger, a second valve in the secondary supply flow path to the secondary heat exchanger, a third valve in a flow path for the compressed air supply to the secondary heat exchanger, a fourth valve in the flow path for cooled compressed supply air from the secondary heat exchanger, and a by-pass valve in the by-pass flow path for compressed cooled supply air from the secondary heat exchanger, a first air flow sensor for sensing air flow from the supply to the primary heat exchanger when the first valve is open, a second air flow sensor for sensing air flow from the secondary heat exchanger along the by-pass flow path when the by-pass valve is open, and a third air flow sensor for sensing air flow of the expanded and cold supply air towards the mixing apparatus, and a controller for controlling each of the valves and for receiving inputs from each of the flow sensors.