Science and Education Publishing Sustainable Energy 2 1 2014 02 06 Simplified Method for Night Sky Radiation Analysis in a Cool-Pool System 29 34 EN Alibakhsh Kasaeian Department of Renewable Energies, Faculty of New Sciences and Technologies, University of Tehran, Tehran, Iran Mohammad Sameti Amin Toghi Eshghi RSE2014216 10.12691/rse-2-1-6 2013 12 17 2014 01 21 2014 02 06 The conventional mechanical building cooling systems are energy demanding equipment. Needing for low-energy consumption systems is a motivation for utilizing ambient energy resources such as ground, ambient air, sky and water as alternative resources. Night sky can be a good candidate as a heat sink to be used in cooling systems. The present study proposes and presents a simplified method for computing net outgoing energy exchanged between night sky and a cool-pool in a building cooling system. Considering a real night condition with a 3 m × 4 m pool and overall energy conversion efficiency of 75%, we obtained that the aforementioned system can replace a 4000 watts swamp cooler works for 6 hours a day.