Building air conditioning system using fuel cell: Case study for Kuwait

Air conditioning machines in Kuwait consume more than 75% of electric energy generated at peak load time. It is in the national interest of Kuwait to decelerate the continuous increase of peak electric power demand. One way to do this is to install for new complexes or high-rise apartments buildings distributed utilities (isolated small power plants), mainly for air conditioning A/C systems. Fuel cells are among the alternatives considered for distributed utilities. This paper discusses the use of commercially available phosphoric acid fuel cell PAFC, known as ONSI P25 to operate air conditioning systems for big buildings in Kuwait. The proposed fuel cell, which is usually delivered with built-in heat exchanger for hot water, is operated by natural gas and uses a propylene glycol-water loop to recover thermal energy. The PAFC has 200 kW nominal electric power capacity, and produces thermal energy of 105 kW thermal energy at 120 °C, and 100 kW at 60 °C. The performance characteristics for the proposed fuel cell are very well documented. In the present study, it is suggested that the fuel cell operates combined mechanical vapor compression and absorption water chillers to utilize the fuel cell full output of electric power and waste heat. Also, to meet the required A/C cooling capacity system by the limited fuel cell power output, it is proposed to use cold storage technique. This allows fuel cell power output to supply the needed energy for average as well as peak A/C system capacity.