Updates on Evaporation and Condensation Methods for the Performance Improvement of Solar Stills (original) (raw)

DEVELOPMENT AND PERFORMANCE EVALUATION OF A SOLAR WATER STILL

The availability of potable water is a necessity for human existence. A simple laboratory scale solar water still capable of holding 75 litres of water has been developed and evaluated. The highest temperature in the solar still occurred at the vapour region and reached up to 66°C. The productivity of the solar still varies with the depth of water in the still. The results of the productivity were 67.4 ml/m 2 h, 54.2 ml/m 2 h and 43.4 ml/m 2 h for depths of 20 mm, 40 mm and 60 mm respectively. The efficiency of the solar still was found to vary with the depth of water in the basin. The highest efficiency obtained for the solar still was 29.1% at a depth of 20 mm. Characterization of water quality before and after distillation in the solar still showed a reduction in chemical and microbiological constituents after distillation which was comparable to standard drinking water. The solar still could be developed at a small-scale workshop at reasonably cheap costs. Further work to improve the productivity of the solar water still is proposed. INTRODUCTION Supply of potable water is a major problem particularly in developing countries. The problem often faced is that protected or improved sources, such as boreholes and treated urban supplies, can still be contaminated such that microbiologically unsafe water is delivered [1]. Of major concern is the populace dwelling in rural regions of developing countries who do not have access to these improved sources and are at higher health risks as they depend on the natural sources like rivers, streams and springs which are often contaminated. The ability to be able to treat water on a domestic scale will therefore be of immense benefit. Nigeria lies within a high sunshine belt and solar radiation is fairly well distributed within the country. The annual average total solar radiation varies from 12.6 MJ/m 2-day in the coastal latitudes to 25.2MJ/m 2-day in the far north [2]. This vast amount of solar energy could be utilized in purifying water domestically. Solar distillation has been largely used in desalination. It involves utilizing solar energy for heating of water to cause evaporation. The vapour produced, then, condenses to produce distilled water. Gomkali and Datta [3] designed a simple solar still with a double-sloped glass cover plate which had an annual average productivity of 2.5 l/m 2-day and at an efficiency of 28%. Naim [4] also devised a single-stage solar desalination spirally-wound module which had maximum distillation efficiency of 34% and with a productivity of 575 ml/m 2-h. Medugu and Malgwi [5] designed and tested a solar still and claimed that the instantaneous efficiency increases with the increase of solar radiation and with increase of feed water temperature. Tarawneh [6] studied the effect of water depth on the performance evaluation of a solar still and stated that decreased water depth has a significant effect on increased water productivity, noting that the productivity of

Solar still with condenser – A detailed review

Access to potable water to the people is narrowing down day after day all over the world. Most of the human diseases are caused by polluted or non-purified water resources. Water purification without affecting the ecosystem is the necessity of the hour. Solar distillation is one of the water purification techniques producing ultrapure distilled water. Solar still distillation systems offer sustainable tools for freshwater production. Numerous environmental and operational parameters attribute to optimize the still design. Different designs were tested by researchers to improve the productivity of solar still. In their experimentations, the solar still integrated with external or internal condenser is deemed to be effective and efficient design. In this detailed survey, we are seeking to introduce, explain and discuss the status of different solar stills integrated with different condensers arrangements.

Experimental Investigation of Solar Still Yield for Evaluation of Evaporation Rate

2015

Drinking water suppliers such as natural sources are limited. So, using wastewater treatment techniques and also sea water desalination methods have been explored for many years. This experimental work considers ZnO nano plate in solar pond providing drinking water using solar power as a renewable energy instead of fossil fuel as a nonrenewable energy. Industrial wastewater from petrochemical plant is treated using solar pond technique. Evaporation rate, ambient temperature, brackish water temperature and produced water are reported in a year. According to the experiments, the highest rate of evaporation is on July, 5.2 (lit/m 2 . day), the highest value of ambient temperature is 34 C on July and the highest amount of insolation rate 24500 (kj/m 2 .day), is obtained on June and August. Results show an evaluation of solar pond technique in wastewater treatment.

A Review on Performance and Heat Transfer Enhancement in Solar Still

International Journal of Scientific Research in Science, Engineering and Technology, 2023

The earth’s surface covers 71% of water area. Drinking water is a necessary thing for all living organism in the earth. But the availability of potable water is no longer available in rapid increase of population. So one of the way to obtain clean water from saline water is solar desalination. Solar desalination is the process of obtaining clean water from saline water. For desalination a device solar still can be employed. The solar still is one of the effective ways of desalinating saline water with an affordable price. Using extended surface the productivity of solar still is increased. The extended surface is modified to improve the evaporation rate and to absorb more solar radiation. Present review paper shows the use of extended surface in solar still and how to increase solar still production.