Experimental investigation of different air heating methods near to the evaporation surface in closed triangular shape unit powered by solar energy, one stage – Indoor experiment

• Published in: Applied thermal engineering 2017-12, Vol.127, p.203-211
• Main Authors: Ladouy, Sara, Khabbazi, Abdelhamid
• Format: Article
• Language: English
• Subjects: Cold surfaces; Desalination; Energy consumption; Energy efficiency; Evaporation; Heat pulses; Heating; Hot air; Humidification-dehumidification cycle (HDH); Impulse heating; Overheating; Productivity; Pulse duration; Pulse heating; Solar energy; Studies
• ISSN: 1359-4311; 1873-5606
• DOI: 10.1016/j.applthermaleng.2017.08.004

•A solar still with continuous and discontinuous air heating have been investigated.•A comparison between two modes of air heating and conventional still is carried out.•Discontinuous way enhances the efficiency by 5% and distillate production by 19%.•Energy consumption for air heating is 5% high than the conventional still. Most of the studies that are made on the solar desalination are focusing on enhancing its productivity by changing the temperature of the solar still, using two methods: either heating water and air or cooling the walls. Each solution is affecting the other; heat increases the temperature of the cold surfaces and vice versa. The originality of this experimental work that falls within the same field of productivity enhancement of the solar desalination is using different air heating modes (time range) next to the evaporation surface in closed triangular shape, one stage. The manipulation consists of air heating without overheating the cold surfaces; this could be possible, using the pulse heating. The setup constructed and tested through indoor experiments, in the shade, where different heat pulses are investigated, while changing the duration of the pulse. The results show that a particular combination of the pulse duration gives an efficiency enhancement of 5% in comparison to the one without air heating. And a distillate production increase of 19%, using a minor energy investment that doesn’t exceed 5%.