Experimental Studies on Single Slope Solar Distillation Unit with Different Coatings on Basin

Research Article

Austin Chem Eng. 2016; 3(5): 1044.

Experimental Studies on Single Slope Solar Distillation Unit with Different Coatings on Basin

Krishna PV*, Sridevi V, Priya BH and Kumar KH

Department of Chemical Engineering, Andhra University, India

*Corresponding author: P Vamsi Krishna, Department of Chemical Engineering, Andhra University, India

Received: October 03, 2016; Accepted: November 09, 2016; Published: November 11, 2016

Abstract

Almost two-third of the earth’s surface is covered with water. In that 97% of the earth’s water is salty; only remaining 3% is fresh water. Less than 1% of fresh water is accessible for humans. The consumption of fresh water is increasing all over the world, mainly due to increase in the population and the rapid industrial growth. This causes a serious shortage of fresh water. So it is very important to conserve the available fresh water. In this regards solar distillation of impure water plays a very important role since its cost of construction is very less, easy to maintain and eco friendly because it uses only solar energy. A solar distillation unit operates similar to the natural hydrologic cycle of evaporation and condensation. There are many factors that affect the efficiency of a solar distillation unit like thickness of the glass plate, solar radiation, direction of the unit, volume of water, material of insulation and material of the basin. In the present research the variation in the performance of the solar distillation unit is studied by using different coatings on basin like copper electroplated Aluminium basin, Aluminium basin with black paint at different volumes of water (2, 2.5, 3 liters) in different directions. The maximum percentage of efficiency is found to be 54.66% when copper electroplated Aluminium basin is used at 3 liters of water and 65.63% when Aluminium basin with black paint is used at 3 liters of water.

Keywords: Solar distillation; Aluminium basin; Copper electroplated Al basin; Al basin with black paint

Introduction

Water is the basic necessity for human along with food and air. There is almost no water left on Earth that is safe to drink without purification. Only 1% of Earth’s water is in a fresh, liquid state, and nearly all of this is polluted by both diseases and toxic chemicals. For this reason, purification of water supplies is extremely important. Moreover, typical purification systems are easily damaged or compromised by disasters, natural or otherwise. This results in a very challenging situation for individuals trying to prepare for such situations, and keep themselves and their families safe from the myriad diseases and toxic chemicals present in untreated water. Everyone wants to find out the solution of above problem with the available sources of energy in order to achieve pure water. Fortunately there is a solution to these problems. It is a technology that is not only capable of removing a very wide variety of contaminants in just one step, but is simple, cost-effective, and environmentally friendly. That is use of solar energy [1]. In general, solar distillation process is carried out both in passive and active modes. Normally passive solar still operates in low temperature and the daily productivity is comparatively low. Whereas, to increase the evaporation rate in an active mode the extra thermal energy is fed into the basin. To increase the productivity of solar still, the various active methods are being carried out by many researchers. Most of the works were based on the flat plate collector and concentrating collector. The single basin solar still coupled with flat plat collector and found that the daily production rate was increased by 24% when compared to the simple single basin solar still by Rai [2]. The maximum yield of a simple solar still was 2.575L/m2 day while it was 5.18L/m2 day when integrated with flat plate collector was found by Tiris [3]. Its production rate was increased by 231% but efficiency has decreased by about 2.5%. The solar still productivity has increased by 36% while coupling flat plat collector was determined by Badran [4]. The productivity was proportional to the solar radiation Badran [5]. An active solar still with water flow over the glass cover has given maximum yield of 7.5L/day was found by Sanjay Kumar [6]. The annual yield was at its maximum when the condensing glass cover inclination was equal to the latitude of the place was concluded by Singh. Solar stills coupled with solar collectors and storage tank both experimentally and theoretically and found that the productivity doubled for 24 hours period was determined by Voropoulos [7-9]. Also, they have designed a hybrid solar desalination and water heating system [10]. In the present study we are mainly focus on the coatings of the basin and how they affect the efficiency of solar distillation unit the we considered are copper electroplating and black paint on a Aluminium basin.

Principle

Solar distillation uses the heat of the sun directly in a simple piece of equipment to purify water. The equipment, commonly called a solar still, consists primarily of a shallow basin with a transparent glass cover. The sun heats the water in the basin, causing evaporation. Moisture rises, condenses on the cover and runs down into a collection trough, leaving behind the salts, minerals, and most other impurities, including germs. Although it can be rather expensive to build a solar still that is both effective and long-lasting, it can produce purified water at a reasonable cost if it is built, operated, and maintained properly [11]. Figure 1 shows the schematic diagram of solar still.