CONFIGURATION AND RELIABILITY OF AN AIR-CONDITIONING SYSTEM FOR TELECOMMUNICATIONS SYSTEMS THAT USES THE HEAT DISSIPATED FROM FUEL-CELLS

NTT Power and Building Facilities Inc. is now developing an air-condit ioning system for telecommunications use that uses the heat dissipated from phosphoric acid fuel cells. The air-conditioning system consists mainly of fuel cells, absorption refrigerator and exhaust-heat-driven air-conditioners. We have investigated the reliability of the air-con ditioning system and have found that the reliability of such a system ran be improved if either multiple absorption refrigerators are used, or if a back-up heat supply facility (burner) is installed in an absor ption refrigerator so that cooling can be performed by stored fuel if the fuel cells fail. We have also found that both an exhaust-heat-driv en air-conditioning system and an electrically driven distributed air- conditioning system must be combined to meet the reliability level req uired of air-conditioning for telecommunications systems. In such a co nfiguration, the number of air-conditioners in the electrically driven distributed air-conditioning system can be reduced by 30 %. Moreover, if reliability can be further improved by enhancing the maintenance s ystem and by incorporating new features, such as a self-diagnostic fun ction for absorption refrigerators, the number of electrically driven air-conditioners can probably be reduced as much as 40-50 %. According ly, the above type of combined air-conditioning system can insure reli ability and also provide an economical, low energy system by using the heat dissipated from fuel cells.