Effect of tilt angle on the performance of a thin-film photovoltaic system

Solar energy is among the cleanest and most sustainable ways to enhance electrical supply's resiliency and reliability for domestic and industrial use. A Photovoltaic (PV) system is the most effective way of capturing solar energy. Long-term warranty, low-cost maintenance, and vast resource availability, solar power generation has an advantage over other approaches. Thin-film technology PV cells are a new kind of solar cell that offers an efficient technique of generating electricity from sunlight. The thin-film PV technology (FFMAT-10, Renovagen, UK) used in this study can supply 0.9 to 1.6 kW of energy to the fast-fold energy hub. The hub’s system status and configuration display battery power input, battery’s state of charge, thin-film PV power and AC power output. Two fast-fold mats (with a surface area of 25.3 m2) were connected to the energy hub. Increasing energy demand coupled with frequent power outages, and inaccessibility of electricity in rural areas necessitates the usage of PV systems at their best performance level. The study objective, therefore, sought to assess the effect of tilt angle on the performance of the thin-film PV system. The study was conducted at Kimicha in Kirinyaga County Kenya, and Juja, Kenya at tilt angles between 0o to 30o. The results indicated that the mean peak PV power for Kimicha was 347.8±231.9 W at 5o and 517.7± 131.3 W at 15ofor Juja. The maximum solar radiation during the study period was 1086.4 ±211.4 W/m2 for Juja and 973.5±219.93 W/m2 for Kimicha. From the study, it was realized that an optimal tilt angle yields optimum solar radiation that translates to maximum power production. Even though the study was conducted in two different regions, it may be applied to any other geographical location. The outcome of the study aids in acquiring self-sustaining power in the most remote locations where electricity is scarce as well as improving energy security

Workplace Violence among Domestic Workers in Urban Households in Kenya: A Case of Nairobi City

This paper discusses findings of a study conducted in 2004/2005 on the prevalence and impact of domestic labour migration in Nairobi. Specifically, the paper examines the profile of domestic workers and extent of their vulnerability and exposure to different forms of abuse. The study integrated both qualitative and quantitative research techniques to attain its objectives. The qualitative approach included key informant survey and in-depth interviews. The quantitative approach on the other hand involved a cross-sectional household stratified sample survey in urban residential areas in Nairobi. The results reveal that overall, children account for a higher proportion of domestic workers, most of them girls from poor family backgrounds. Child domestic workers in Nairobi face many workplace social hazards that include injury, verbal harassment and sexual abuse. Based on these findings, the study makes appropriate policy recommendations. Eastern African Social Sciences Review Vol. 23 (1) 2007: pp. 37-6

PERFORMANCE EVALUATION OF AN EVAPORATIVE CHARCOAL COOLER UTILIZING THIN-FILM PHOTOVOLTAIC SYSTEM FOR PRESERVATION OF AVOCADO

Fruits are high moisture agricultural produce rendering them highly perishable hence the danger of postharvest losses is also lurking when there are inadequate storage facilities. The losses result from physical, chemical, and physiological changes that are triggered by the loss in moisture content. Preservation of fruits using available and affordable technologies (such as charcoal coolers) can benefit small-scale farmers in minimizing postharvest losses. An evaporative charcoal cooler 4 m long, 4 m wide, and 2.5 m high providing a 40 m3 storage capacity was utilized in the study. The cooler with a 150 mm wide cavity filled with charcoal had a perforated pipe connected to a 1000-litrecistern raised at 2.5 m above the ground and connected to a water pump (Pedrollo PKm 60, Italy) that kept the charcoal wet by a drip system. The pump and the three axial fans (REC-21725 A2 W, USA) rated 180 cubic feet per minute (CFM) and 2600 revolutions per minute (RPM) were powered by fast fold thin-film PV (FFMAT-10, Renovagen, UK) system connected to a 10-kWh rated energy hub (FFENERGYHUB-10, Renovagen, UK). Temperature, relative humidity and product quality parameters (weight loss, total soluble solids, vitamin C content and firmness were evaluated).The evaporative cooler temperatures reduced significantly (P<0.05) with an average 25.0±0.37 oC and 32.1±0.99 ºC outdoors temperatures. The cooler relative humidity increased significantly (P˂0.05) averaging 76.8±1.6% and 43±2.8% for ambient conditions. The average cooling efficiency in the charcoal cooler was 83.0%.The percentage weight loss of the avocado was 3.9% and 7.5% for the cooler and outdoors respectively. The percentage vitamin C loss was 39.0% for the cooler and 49.6% for those kept outside. The total soluble solids in the cooler rose from 0.5 to 1.6 oBrix and 0.5 to 2.6 oBrix in ambient conditions. Firmness decreased from an average 65.0 N to 10.7 N and 65.0 N to 8.0 N after 12 days for samples in the cooler and ambient conditions, respectively. In conclusion, the evaporative charcoal cooler incorporated with thin-film PV system preserved the postharvest quality and extended the shelf life of hass avocado