Abstract: A heat exchanger is disclosed for cooling a gas from a first temperature to a second temperature. The exchanger comprises a first heat exchanging chamber, a second heat exchanging chamber and an array of heat pipes which are arranged to extend from within the first heat exchanging chamber to within the second heat exchanging chamber. The first heat exchanging chamber comprises an inlet for receiving a coolant into the chamber and an outlet through which the coolant can exit the first chamber, the coolant being arranged to pass over the portion of the heat pipes which extend within the first chamber. The second heat exchanging chamber comprises an inlet for receiving the gas at a first temperature into the chamber and an outlet through which the gas can exit the second chamber at a second temperature.

Abstract: A heat exchanger is disclosed for exchanging heat between a first gas and a second gas. The heat exchanger comprises a first heat exchanging chamber, a second heat exchanging chamber and an array of heat pipes which are arranged to extend between the first and second heat exchanging chambers. The first heat exchanging chamber comprising an inlet for receiving the first gas into the chamber and an outlet through which the first gas can exit the first chamber, the flow of first gas being substantially along the array of heat pipes. The second heat exchanging chamber comprising an inlet for receiving a second gas into the chamber and an outlet through which the second gas can exit the second chamber, the flow of second gas being substantially across the array of heat pipes. The flow of second gas is split into two subsidiary flow paths, with each subsidiary flow path comprising a substantially identical array of heat pipes. This ensures that each heat pipe receives a similar rate of heat exchange.