Category Solar energy

RECENT DEVELOPMENTS IN FLAT-PLATE PVT

1.3.1 PVT AIR COLLECTOR SYSTEMS

1.3.1.1 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 [29]...

Read More

DEVELOPMENTS TOWARDS COMPLEX SYSTEMS

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 [18]. 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

PVT DEVELOPMENTS IN THE TWENTIETH CENTURY

1.2.1 EARLY WORKS ON COLLECTOR DESIGN

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 [12] 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 [13] derived a detailed physical model of a flat-plate PVT/w collector, through which the total efficiency was evaluated.

de Vries [14] investigated the performance of several PVT collector desig...

Read More

HYBRID SOLAR: A REVIEW ON PHOTOVOLTAIC AND THERMAL POWER INTEGRATION

T. T. CHOW, G. N. TIWARI, and C. MENEZO

1.1 INTRODUCTION

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

APPLICATION, ECONOMICS,. AND PUBLIC PERCEPTION

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