| Energy consumption in the underground subway mechanism is highly influenced by the air conditioning(AC) system. By considering the dedicated tunnel ventilation system, this paper proposes an energy-efficient AC system incorporating an independent evaporative condenser for application at a subway station in Beijing, China. Cooling performance of the newly developed AC system is investigated through a series of field experiments. The main characteristic parameters that influence the AC cooling performances are discussed, such as air velocity, water flow rate, dry-bulb temperature and the power consumption of water pump, compressor as well as air supply fan. A comparative study is further conducted between the evaporative-condenser based AC system and a conventional AC system in order to illustrate the corresponding energy-saving potential. It is found that the new AC system could be a potential solution to the existing technical defects existing in the conventional subway AC system. The coefficient of performance(COP) of the evaporative-condenser based AC system is observed at nearly 6.75. Furthermore, the COP of conventional AC system is tested at about 3.16. The research results indicated that the evaporative-condenser incorporated AC system can be potential solutions to enhance the energy efficiency and reduce operational cost in contemporary subway environment. |
