Hafiz Muhammad Ali

Comparison of Performance Measurements of Photovoltaic Modules during Winter Months in Taxila, Pakistan

This paper presents the comparative performance evaluation of three commercially available photovoltaic modules (monocrystalline, polycrystalline, and single junction amorphous silicon) in Taxila, Pakistan. The experimentation was carried out at outdoor conditions for winter months. Power output, module efficiency, and performance ratio were calculated for each module and the effect of module temperature and solar irradiance on these parameters was investigated. Module parameters showed strong dependence on the solar irradiance and module temperature. Monocrystalline and polycrystalline modules showed better performance in high irradiance condition whereas it decreased suddenly with decrease in irradiance. Amorphous solar module also showed good performance in low irradiance due to its better light absorbing characteristics and thus showed higher average performance ratio. Monocrystalline photovoltaic module showed higher monthly average module efficiency and was found to be more efficient at this site. Module efficiency and performance ratio showed a decreasing trend with increase of irradiance and photovoltaic module back surface temperature.

Performance Investigation of Air Velocity Effects on PV Modules under Controlled Conditions

Junction temperature of PV modules is one of the key parameters on which the performance of PV modules depends. In the present work, an experimental investigation was carried out to analyze the effects of air velocity on the performance of two PV modules, that is, monocrystalline silicon and polycrystalline silicon under the controlled conditions of a wind tunnel in the presence of an artificial solar simulator. The parameters investigated include the surface temperature variation, power output, and efficiency of PV modules under varying air velocity from near zero (indoor lab. conditions) to 15 m/s. Additionally, the results were also determined at two different module angular positions: at 0° angle, that is, parallel to air direction and at 10° angle with the direction of coming air to consider the effects of tilt angles. Afterwards, the thermal analysis of the modules was performed using Ansys-Fluent in which junction temperature and heat flux of modules were determined by applying appropriate boundary conditions, such as air velocity, heat flux, and solar radiation. Finally, the numerical results are compared with the experiment in terms of junction temperatures of modules and good agreement was found. Additionally, the results showed that the maximum module temperature drops by 17.2°C and the module efficiency and power output increased from 10 to 12% with increasing air velocity.

Enhanced Condensation of Ethylene Glycol on Three-Dimensional Pin-Fin Tubes

New experimental data are reported for condensation of ethylene glycol at near atmospheric pressure and low velocity on six three-dimensional pin-fin tubes. Enhancements of the vapour-side, heat-transfer coefficients were found between 3 to 5.5 when compared to a plain tube at the same vapour-side temperature difference. Heat-transfer enhancement was found to be strongly dependent on the active surface area i.e. on the proportion of the tube and pin surface not covered by condensate retained by surface tension. For all the tubes, vapour-side, heat-transfer enhancements were found to be approximately 3 times the corresponding active-area enhancements. The best performing pin-fin tube gave a heat-transfer enhancement of up to 5.5; 17% higher than those obtained from ‘optimised’ two-dimensional fin-tubes reported in the literature and about 24% higher than the ‘equivalent’ two-dimensional integral-fin tube (i.e. with same fin root diameter, longitudinal fin spacing and thickness and fin height).Copyright

Addition of molasses, corn steep liquor, and rice polish as economical sources to enhance the fungal biomass production of wheat straw by Arachniotus sp.

Faisal SHAHZAD*, Muhammad ABDULLAH, Abdul Shakoor CHAUDHRY, Abu Saeed HASHMI, Jalees Ahmed BHATTI, Makhdum Abdul JABBAR, Hafiz Muhammad ALI, Tauseef Ur REHMAN, Farah ALI, Mian Muhammad Khubaib SATTAR, Fayyaz AHMED, Irfan IRSHAD University College of Veterinary and Animal Sciences, The Islamia University of Bahawalpur, Bahawalpur, Pakistan Department of Livestock Production, University of Veterinary and Animal Sciences, Lahore, Pakistan School of Agriculture, Food and Rural Development, Newcastle University, Newcastle upon Tyne, United Kingdom Institute of Biochemistry and Biotechnology, University of Veterinary and Animal Sciences, Lahore, Pakistan Punjab Agricultural Research Board, Lahore, Pakistan Buffalo Research Institute, Pattoki, Pakistan Department of Pathology, University of Veterinary and Animal Sciences, Lahore, Pakistan

Key design features of multi vacuum glazing for windows: A review

The use of vacuum glazed windows is increasing due to their application in mod-ern building design. Among various types of vacuum glazed windows reported in literature, thermal transmittance of single glass sheet (conventional window) i. e 6 W/m2k is reduced by 66 and 77% using air filled double glazed and air filled triple glazed windows, respectively. Using low emittance coatings thermal transmittance of double glazed windows is reduced by 53%, however it offsets the visibility by reduc-ing light transmittance by 5%. Stresses due to temperature/pressure gradients if not eliminated may lead to reduction in service life of vacuum glazed windows. Vacuum created between the glass sheets is used to reduce conductive heat transfer. Degrada-tion in the vacuum is caused by number of factors such as, permeation of gaseous molecules through glass sheets, leakage through sealing, thermal/optical desorption, and photo-fragmentation of organic species have been critically reviewed and future trends are outlined.

Condensation Heat Transfer on Geometrically Enhanced Horizontal Tube: A Review

In this chapter, an attempt has been made to present the recent state of knowledge of free-convection condensation heat transfer on geometrically enhanced tubes. This survey is divided into three sections. The first section concentrates on research on condensate flooding or retention. The second and the third sections cover the experimental and the theoretical work on geometrically enhanced tubes, respectively.