This paper presents the results of a field study undertaken all over the Punjab, Pakistan, to evaluate the socio-economic and climatic impact of photovoltaic-operated high-efficiency irrigation systems (HEIS), i.e., drip and sprinkler irrigation systems. Nearly half of the rural population relies on agriculture for a living, and the recent energy crisis has had a negative impact on rural communities. Farmers’ reliance on fossil fuels for the operation of irrigation systems has increased exponentially, resulting in the high costs of agricultural production. Primary data regarding on-farm agriculture and irrigation practices used in this study were collected through an intensive on-farm survey, while secondary data were taken from published reports and statistics. The results of the current investigation show that the installation of PV systems has resulted in the increased adoption of high-efficiency irrigation systems, a reduction in the high operational costs incurred on account of old diesel-powered pumping systems (with an annual saving of 6.6 million liters of diesel), a 100% increase in farmer’s income, a reduction of 17,622 tons of CO2 emissions per annum, and 41% savings in water. The unit cost of PV-powered HEIS was found to be 0.1219 USD/kWh, which was 4% and 66% less than subsidized electricity cost and diesel cost, respectively.

Fossil fuels are being depleted, resulting in increasing environmental pollution due to greenhouse gases and, consequently, emerging detrimental environmental problems. Therefore, renewable energy is becoming more important; hence, significant research is in progress to increase efficient uses of solar energy. In this paper, the thermal performance of a conical concentrating system with different heat transfer fluids at varied flow rates was studied. The conical-shaped concentrator reflects the incoming solar radiation onto the absorber surface, which is located at the focal axis, where the collected heat is transported through heating mediums or heat transfer fluids. Distilled water and nanofluids (Al2O3, CuO) were used in this study as the heat transfer fluids and were circulated through the absorber and the heat storage tank in a closed loop by a pump to absorb the solar radiation. The efficiency of the conical concentrating system was measured during solar noon hours under a clear sky. The collector efficiency was analyzed at different flow rates of 2, 4, and 6 L/min. The thermal efficiency, calculated using different heat transfer fluids, were 72.5% for Al2O3, 65% for CuO, and 62.8% for distilled water. Comparing the thermal efficiency at different flow rates, Al2O3 at 6 L/min, CuO at 6 L/min, and distilled water at 4 L/min showed high efficiencies; these results indicate that the Al2O3 nanofluid is the better choice for use as a heating medium for practical applications.

This paper discusses the effectiveness of simultaneous use of CuO nanofluid and air as a dual-fluid coolant for the thermal management of a photovoltaic/thermal (PV/T) system. Outdoor experimental studies were performed to calculate the discrepancies between indoor and outdoor test findings. The thermal efficiency and the electrical characteristics of the dual-fluid PV/T system were investigated under steady-state test conditions following ISO standards. It was found that the divergence in electrical efficiency between indoor and outdoor-based PVT testing was significantly higher, while the difference in thermal efficiencies was marginal. It was observed that nanofluid/air, even at the lowest flow rates, outclassed the water/air coolant at higher flow rates in terms of PV/T energy output, which also ultimately helps in reducing the energy requirement for pumping. Unlike conventional solar air heaters, the proposed dual-fluid PV/T system produces a high air temperature when operated with only air at stagnant nanofluid. The maximum PV/T efficiency of approximately 85% was recorded when the nanofluid and air flows were kept at 0.02 kg/s and 0.04 kg/s, respectively. It is concluded that outdoor steady state testing provides comprehensive performance characterization of the nanofluid powered dual-fluid coolant for the PV/T system.

Rheological properties of cereals such as rye are great important for the design of die for extrusion and the development of models for extrusion process. Therefore, this study was carried out to analyze the rheological properties according to moisture content of rye flour and extrusion temperature. Rheological properties of rye flour were investigated by using a capillary rheometer for moisture content of three levels (30, 35, 40%) and extrusion temperature of three levels (120, 130, 140℃). Determination coefficients for the relationship between apparent shear stress (τap) and apparent shear velocity (ϒap) were relatively high in the range of 0.973 ~ 0.997 under each extrusion condition. The values of consistency index (K) was decreased with increasing moisture content and extrusion temperature. However, the value of flow behavior index (n) presented the highest value at moisture content of 35%, but it was not affected by extrusion temperature.

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