Dual-mode operation by solar energy of an ammonia-water two-stage cycle: A comparative study☆

The performance of a multi-stage ammonia absorption unit has been computed using data for Port Moresby, Papua New Guinea. The operation of the unit was in dual mode: below a predetermined insolation rate the system operated on a single stage resorption cycle and above that insolation rate on a 2-stage cycle. The performance of this system with a collector area of 100 m2 was computed and compared to the performance of a LiBr unit. The cooling demand of a house, 10 × 20 × 3 m, was also assessed. It is found that on a day when the total insolation was about 5360 mWh (cm)−2 (more than 65 per cent of the days receiving more than this value) the ammonia system could meet the cooling demand. It is also observed that the collector area for the LiBr unit with the same capacity is about 40 per cent more. The capital cost of the ammonia system including the collector would therefore be less than the cost of the corresponding LiBr system.