In the last 10 years, research has been done in the area of two-phase thermosiphon loop heat exchangers for recovering waste heat from exhaust air for preheating the incoming supply air during the winter. While attention mainly has been focused on preheating the outside air with the use of two- phase thermosiphon loop heat exchangers, the system can be used for precooling the outside air during the summer. A computer program capable of simulating such systems was developed by Mathur (1986). The program has been modified to model and simulate the performance for summer conditions with the use of evaporative cooling. Different types of evaporative cooling systems that can be used with two-phase thermosiphon loop heat exchangers are discussed. Simulated results show a significant reduction in cooling operation and equipment costs if the indirect evaporative cooling principle is applied to a two-phase thermosiphon loop heat exchanger system.

KEYWORDS: evaporative cooling, indirect cooling, thermosiphon, heat exchangers, calculating, models, computer programs, performance, costs.