Category Solar energy
22.214.171.124 COLLECTOR DESIGN AND PERFORMANCE
The PVT air collectors, either glazed or unglazed, provide simple and economical solution to PV cooling. The air can be heated to different temperature levels through forced or natural flow. Forced circulation is more effective than natural circulation owing to better thermal convective and conductive behavior, but the fan power consumption reduces the net electricity output. Their use is mostly to meet the demands on industrial hot air, indoor space heating, and/or agricultural dehydration.
Hegazy investigated the thermal, electrical, hydrodynamic, and overall performance of four types of flat-plate PVT/a collectors ...Read More
In the 1990s, the initiative of PVT research was apparently a response to the global environmental deterioration and the growing interest in building-integrated photovoltaic (BiPV) designs. Comparing with the separated PV systems, the building integration of PV modules improves the overall performance and durability of the building facade. Nevertheless, building integration may bring the cell temperatures up to 20°C above the normal working temperature . Other than the benefits of cooling, PVT collectors provide aesthetical uniformity than the side-by-side arrays of PV and solar thermal collectors. Alternative cooling schemes of the BiPV systems were examined [19-21]...Read More
The early research works were mainly on flat-plate collectors [5, 6]. Garg and his coworkers carried out mathematical and experimental studies on PVT systems [7-9]. Sopian et al. developed steady-state models, for comparing the performance of single- and doublepass PVT/a collectors [10, 11]. Through transient analysis, Prakash  pointed out that the air collector (PVT/a) design is lower in thermal efficiency than the water collector (PVT/w), because of the inferior heat transfer between the thermal absorber and the airflow stream. Bergene and Lovvik  derived a detailed physical model of a flat-plate PVT/w collector, through which the total efficiency was evaluated.
de Vries  investigated the performance of several PVT collector desig...Read More
T. T. CHOW, G. N. TIWARI, and C. MENEZO
In the past 3-4 decades, the market of solar thermal and photovoltaic (PV) electricity generation has been growing rapidly. So were the technological developments in hybrid solar photovoltaic/thermal (PVT) collectors and the associated systems. Generally speaking, a PVT system integrates photovoltaic and solar thermal systems for the co-generation of electrical and thermal power from solar energy. A range of methods are available such as the choices of monocrystalline/polycrystalline/amorphous silicon (c-Si/ pc-Si/a-Si) or thin-film solar cells, air/liquid/evaporative collectors, flat- plate/concentrator types, glazed/unglazed designs, natural/forced fluid flow, and stand-alone/building-integrated features...Read More
Due to global decline in fossil fuel reserves and contribution of their emissions (during the extraction, production and utilization processes) to climate change, many countries are now examining their national energy policies with a view of shifting toward low-carbon and renewable sources of energy. In addition, security of supply and fluctuations in crude-oil prices (which can be sensitive to internal and regional conflicts) can lead to economic vulnerability of oil-importing countries. Furthermore, the exporting countries can use the price of these resources to settle political differences.
As a result of recent trends in solar energy development due to improved technology, cost reduction in solar energy application equipment, and possible use with energy storage systems, sola...Read More