A.E. Kabeel

Augmentation of the basin type solar still using photovoltaic powered turbulence system

Abstract The present paper concerns with enhancing productivity of basin type solar still through experimental investigation. Therefore, two solar stills are designed and constructed to study the performance of two suggested solar desalination systems. The first one is a conventional still and the second is a modified still uses a rotating fan with a vertical shaft. A DC-motor powered by a small photovoltaic (PV) system is used to rotate the fan. The influence of the rotational speed of the fan and the depth of saline water on the performance of the still is investigated experimentally. The experiments were conducted with fan rotational speeds of 30, 35, 40 and 45 rpm and saline water depths of 1, 3, 5 and 7 cm. The results indicate that the daily productivity of still increases with increasing rotational speed of the fan and the maximum difference of daily productivity between fan and conventional solar stills is achieved at depth of saline water of 3 cm (with rotation). Also it is found that using rotat...

Performances of pyramid-shaped solar still with different glass cover angles: Experimental study

In this study, the effects of glass cover angle on the performance of a square pyramid solar still is investigated experimentally under ambient conditions of Tanta City - Egypt (Latitude 30.47°N and longitude 31°E). In this work, the three type of a square pyramids solar still (system-A, system-B and system-C) with inclined angles of the condensation surface are 30.47°, 40° and 50° respectively. The three type of a square pyramids solar still with the same absorber area of 0.64 m2 and a glass cover in the form of a pyramid has been designed and constructed. From the present study, it is concluded that the temperature difference between the basin water and glass cover and the glass cover angles are important for designing square pyramid solar still. This exprimental results shows that the accumulated distillate water productivity up to almost 4.13 L/m2 day in the system-A, 3.5 L/m2 day in the system-B and 2.93 L/m2 day in the system-C. The increase in accumulated distillate water for system-A is 41 % compared to the system-C and 18 % compared to system-B. It was found that, the accumulated distillate water productivity from the square pyramid solar stills decrease with increase the glass cover angle above the Latitude angle. The maximum accumulated distillate water productivity from the square pyramid solar stills occurs when the glass cover angle equal to the Latitude angle.

An innovative solar water collector using heat pipe with inner rings

The performance of a new-design flat plate solar water collector was studied in the current work. The influences of the inner rings and their axial distance, in the absorber surface heat pipe, on the performance of a new-design flat plate solar water collector were studied. Fluid flow and heat transfer in the collector panel were numerically simulated using the computational fluid dynamics (CFD) technique. The results of the flow distribution along the absorber surface of the heating pipe showed that; for the case of heat pipe without inner rings, the water outlet temperature from the heat pipe reached to 326.8 K. While; in the case of using the inner rings, at an axial distance of 5 cm, the water outlet temperature was increased to 338.8 K, for the same simulation conditions. Also, the maximum calculated efficiency of the solar collector for the case without using the inner rings was 60 %, while this value recorded 82.2 % for that case of using the inner rings. The current research work was compared against a previous experimental work running at the same conditions. The comparisons showed a considerable agreement between the simulated and the experimental results.

Economic and exergy investigation of triangular pyramid solar still integrated to inclined solar still with baffles

ABSTRACT This paper presents the detailed exergy and economic investigation of triangular pyramid solar still under passive and active mode of operation. For validation, experiments were carried out at different water depth maintained inside the basin under a continuous flow of water from an inclined solar still. Results confirm that the effect of integration rises the exergy efficiency during the offshine period, whereas during the sunshine hours the exergy efficiency decreases when the maintained the depth of water inside basin decreases. Similar study on economic analysis shows that the net pay back period increases from 5.6 to 11.4 with an increase in the water depth at an average selling price of water Rs 5/kg in a standalone triangular pyramid solar still.

Solar-based atmospheric water generator utilisation of a fresh water recovery: A numerical study

In many regions in the world, the climate conditions are suitable for generating drinkable water; however, they have one or more types of water scarcity. An alternative method for fresh water recovery from atmosphere had been studied in this paper. The studied method is designed for Arabic Gulf countries or similar by using solar-based thermoelectric generator utilisation. The existence of solar energy and humid air gives a good chance for effective productivity. Nowadays, the mathematical model is able to give a good representation of the different cases. The use of recent numerical modelling is robust enough to give accurate results with cost and time saving. For simplification; the cases in this paper were supposed to be the fluid flow region, it means that the simulation will not be involved in the multi physics. The cases have been simulated in 3D using commercial CFD software called Star-CCM+. For the proposed system, four parameters were studied, which were the pressure drop over the flow bath, the water productivity per square metre as the goal parameter and the influence of ambient temperature as well as humidity. The ambient conditions were considered as the design parameters. The three different climatic regions are Red Sea, Arabic Gulf, and southern Europe (south Spain). Only summer climatic conditions are considered. It is found that the pumping power required for air fan did not exceed 9.1 W. Fresh water productivity of the unit was up to 3.9 L/h/m2.

Thermal solar water heater with H2O-Al2O3 nano-fluid in forced convection: experimental investigation

This paper describes laboratory experiments with a thermal solar water heater consisting of a flat-plate solar collector and helical coil heat exchanger using Al2O3 nano-particles dispersed in water as a working. The experiments were carried out for various nano-particle concentrations, from 0% to 3% (by volume), through forced convection cooling. The experiments were carried out under the climatic conditions of Tanta University, Egypt. The laboratory work has been carried out in actual thermal environment in August 2013. The experiments have an emphasis on the main parameters with impact on the water production temperature. These parameters include the solar radiation, the feed water mass flow rate and the nano-particle volume fraction. The main conclusion is that considerable improvement in the daily solar collector efficiency is obtained with increasing the nano-particle concentration up to 11% for concentration 3% with; this increase in efficiency is bounded by ±10% uncertainty. The outlet water temperature is increased with increasing of nano-particle concentration by 5.46% for concentration 2%. The helical heat exchanger effectiveness is increased by 4.25% for a concentration of 1% with ±13% uncertainty. The helical heat exchanger effectiveness and solar collector efficiency are increased with decreasing the working fluid mass flow rate.

A theoretical study of Cu-H2O nano-fluid effect on heat transfer enhancement of a solar water heater

ABSTRACT In the present work, an attempt has been made to enhance the heat transfer in a solar water heater by using Cu nano-particles dispersed in water for various concentrations ranging from 0% to 5%. Considerable improvement in the solar collector efficiency is obtained by increasing the nano-particle concentration up to 17.5 for a concentration of 5% and for a mass flow rate ratio of 10. The outlet water temperature increases by increasing the nano-particle concentration up to 8.35% for a concentration of 5% and for a mass flow rate ratio of 5. The study showed that the solar heater collecting area takes into account significant factors for increasing the outlet temperature. An increase in the collecting area of the solar water heater by 6 times could increase the water temperature by 39% for a 5% nano-particle volume fraction. The helical heat exchanger effectiveness is increased up to 65.71 for a concentration of 5% for a mass flow rate ratio of 10.