Performance characteristics of a solar humidification dehumidification unit using packed bed of screens as the humidifier

Abstract

The aim of the present work is to investigate the main factors affecting the performance improvement of a solar humidification-dehumidification unit (HD), using a packed bed of screens as the humidifi er. The HD unit consists mainly of a flat plate solar collector, humidification section and dehumidification exchanger. The investigation was divided into three main parts which are

Part 1: investigation of the main variables affecting the solar collector performance. It was found that the efficiency of solar collector increased by increasing the collector angle of inclination up to 45°, increasing the area of solar collector, and decreasing the inlet water flow rate.

Part 2: investigation of the humidification-dehumidification unit separated from the solar collector and using external source of heating. It was found that, the productivity of the unit increased by increasing the saline water inlet temperature, saline water flow rate, and thickness of screen packing.

Part 3: the overall system components were assembled, and investigated under different conditions, the results show that, the unit productivity increased by increasing inlet saline water fl ow rate up to 5 L/min and then it is decreased by increasing the inlet flow rate beyond this value, and increased by increasing the thickness of packed bed up to 40 cm and then decreased by increasing the thickness above this value. Recycling of the hot brine out of the humidification section was found to increase the unit productivity by a factor of 214% than the system without recycling. The average unit productivity per day was about 9 L per m² of collector area

Keywords:

• Desalination
• Solar collector
• Humidification-dehumidification process
• Packed bed Screen packing
• Productivity of humidification dehumidification unit
• Efficiency of solar collector