Experimental study on a self-refrigerated auto air conditioning system based on LNG-fuelled trucks

Abstract

The authors proposed and investigated a novel self-refrigerated auto air conditioning system for Liquefied Natural Gas (LNG) fuelled trucks. The cold energy in cryogenic fuel, LNG, was drawn and reused to cool the driver's cab. After theoretical analyzing the available cooling capacity and thermal performance of the new system, the refrigerating performance including cold load, temperature characteristics of the heat exchangers were investigated experimentally under different operating conditions. The results showed that (1) the recovered cooling capacity could cover the heat load of driver's cab (4.1 kW) when LNG consumption rate is larger than 20 kg/h; the maximum cooling capacity is up to 8.746 kW which is about twice of the cooling demand; (2) in order to supplying adequate cooling capacity for the driver's cab, the shaft power of the equipped engine should be not less than 105 kW which accounts for 37.5% of its maximum power capacity; (3) The heat exchangers of the proposed system operated properly, and the desired cooling recovery performance was achieved successfully. However, the LNG vaporizer should be designed more carefully and accurately. The study indicates that the self-refrigerated air conditioning system for LNG-fuelled trucks is feasible and the cooling capacity storage methods must be employed to adjust the mismatch of the cold supply and demand caused by the fluctuation of the LNG consumption rate.