Abstract: A coupled global model of fluid flow and heat transfer was developed for a cold store in use. The convective heat transfer in the springhouse, the jet flow of the air curtain installed at the entrance and the environmental flow outside the cold store were solved together in a coupled way. The effects of the outlet width, the jet velocity and the jet angle of the air curtain on its performance and efficiency were numerically studied respectively under the condition that the air curtain and store gate opened simultaneously. The results showed that there existed an optimal value for the jet velocity and the jet angle at which the air curtain had the best performance and the highest efficiency. A large outlet width does not necessitate for better performance of an air curtain if it exceeds the critical value.