Experimental and numerical investigation of a solar eductorassisted low-pressure water desalination system  

作　　者：Mehran Ahmadi Poovanna Thimmaiah Majid Bahrami Khaled Sedraoui Hani H.Sait Ned Djilali 

机构地区：[1]Laboratory for Alternative Energy Conversion (LAEC), School of Mechatronic Systems Engineering, Simon Fraser University [2]Renewable Energy Research Group, King Abdulaziz University [3]Department of Mechanical Engineering, and Institute for Integrated Energy Systems, University of Victoria

出　　处：《Science Bulletin》2016年第12期959-973,共15页科学通报（英文版）

基　　金：provided in part by the Deanship of Scientific Research, King Abdulaziz University, Jeddah, under Grant No. (1-135-36-Hi Ci)

摘　　要：Greenhouse solar-energy driven desalination technology is potentially well suited for supplying water and small scale irrigation in remote and/or rural areas, and for avoiding over-exploitation of available water resources. The efficiency and productivity of these systems are however low, in part because the heat of evaporation has to be transferred as waste heat to ambient air during condensation. In order to maximize energy regeneration during condensation we propose an educator based system that lowers the evaporation process temperature by reducing pressure. The feasibility of the educator assisted passive solar desalination system is investigated using a detailed computational fluid dynamics analysis complemented by experiments. The study focuses in particular on the ability of the new design to lower the required evaporation temperature and thereby reduce the energy intensity of the process. Two configurations, with open and closed educator, are investigated and a detailed analysis of the thermofluid processes is presented. The configuration with a closed educator installed outside the evaporation chamber shows very promising performance. The proposed system can maintain the maximum temperature and pressure in theevaporation chamber below the desirable temperature and pressure thresholds （30 ℃ and 5 kPa）. The analysis and experimental data also show it is possible to further reduce energy requirements by reducing the motive water flow rates.Greenhouse solar-energy driven desalination technology is potentially well suited for supplying water and small scale irrigation in remote and/or rural areas, and for avoiding over-exploitation of available water resources.The efficiency and productivity of these systems are however low, in part because the heat of evaporation has to be transferred as waste heat to ambient air during condensation. In order to maximize energy regeneration during condensation we propose an educator based system that lowers the evaporation process temperature by reducing pressure. The feasibility of the educator assisted passive solar desalination system is investigated using a detailed computational fluid dynamics analysis complemented by experiments. The study focuses in particular on the ability of the new design to lower the required evaporation temperature and thereby reduce the energy intensity of the process. Two configurations, with open and closed educator, are investigated and a detailed analysis of the thermofluid processes is presented. The configuration with a closed educator installed outside the evaporation chamber shows very promising performance. The proposed system can maintain the maximum temperature and pressure in the evaporation chamber below the desirable temperature and pressure thresholds(30 °C and 5 k Pa). The analysis and experimental data also show it is possible to further reduce energy requirements by reducing the motive water flow rates.

关 键 词：Desalination. Solar energy EvaporationHumidification DEHUMIDIFICATION Regenerative heating 

分 类 号：P747[天文地球—海洋科学] TU991.3[建筑科学—市政工程]