Heat rejection technologies for Solar Combi+ systems: dry cooler and wet cooling tower

摘要

In the present work the attention is focused on the heat rejection part of solar combi+ systems looking at the performance of two different technologies: air-cooled heat exchanger and wet cooling tower. A deck for dynamic simulations in TRNSYS of a small Solar combi+ system has been prepared, where a thermally driven chiller with both the technologies runs. The air-cooled heat exchanger is simulated by an EES based code. In this investigation the effects of three different climates, resulting in different available dry and wet bulb temperatures, on the performance of the heat rejection equipment and of the solar combi+ system are studied. In particular the specific primary energy consumption per unit of rejected heat and the specific costs of the heat rejection per unit of cooling energy produced by the chiller are calculated. For the geometries of the cooling tower and dry cooler here considered and without implementing any fan speed control strategy, the results show that the wet cooling tower has a lower primary energy consumption and specific cost compared to the dry cooler in all the three different locations.