P. Ooshaksaraei

Characterization of a Bifacial Photovoltaic Panel Integrated with External Diffuse and Semimirror Type Reflectors

Silicon wafer accounts for almost one-half the cost of a photovoltaic (PV) panel. A bifacial silicon solar cell is attractive due to its potential of enhancing power generation from the same silicon wafer in comparison with a conventional monofacial solar cell. The bifacial PV cell is able to capture solar radiation by back surface. This ability requires a suitable reflector appropriately oriented and separated from the cell’s rear surface. In order to optimize the bifacial solar cell performance with respect to an external back surface reflector, diffuse and semimirror reflectors were investigated at various angles and separations from the back surface. A simple bifacial solar panel, consisting of four monocrystalline Si solar cells, was designed and built. Reflection from the rear surface was provided by an extended semimirror and a white-painted diffuse reflector. Maximum power generation was observed at 30° with respect to ground for the semimirror reflector and 10° for diffuse reflector at an optimized reflector-panel separation of 115 mm. Output power enhancement of 20% and 15% from semimirror and diffuse reflectors, respectively, were observed. This loss from diffuse reflector is attributed to scattering of light beyond the rear surface capture cross-section of the bifacial solar panel.

Steady state characterization of bifacial solar cells at different configurations of air-based photovoltaic thermal solar panels

This paper examines the first and second law efficiency of bifacial photovoltaic thermal (PVT) solar collectors. A mathematical model was developed to evaluate the system performance. Four air-based bifacial photovoltaic thermal panels were also designed based on the bifacial PV cell requirement. Most of the existing PVT designs contain an absorber plate, which in this research is replaced by a reflector to avoid blocking the rear aperture of bifacial cells. The following four air-based panel configurations were considered: single-path; double-path, parallel; double-path, counter flow; and double-path, returning flow. All four panel designs evaluated based on the first law and second law of thermodynamic, at steady state mode. Energy and exergy efficiencies of aforementioned designs strongly depend on packing factor and air mass flow rate. From an energy point of view (first law), the bifacial photovoltaic thermal panel with two parallel air streams exhibited the best efficiency (51%–67%) compared with th...

Effect of compaction pressure on the performance of a non-symmetrical NiO–SDC/SDC composite anode fabricated by conventional furnace

Abstract The electrochemical performance of NiO–SDC/SDC anode was studied. The anode was compacted by pressing, after which sintering was conducted in a conventional furnace at 1200 °C. A high-energy ball mill was used to mix the Sm0.2Ce0.8O1.9 (SDC) nanopowder and NiO. A pressing technique was applied to fabricate the NiO–SDC/SDC anode cells. The effect of different compaction pressures (200, 300, and 400 MPa) on the performance of the anodes was investigated via electrochemical impedance spectroscopy at an intermediate temperature range (600–800 °C). The nanoindentation technique and Archimedes method, which were used to measure stiffness and bulk density, respectively, revealed that increases in porosity were correlated with decreases in compaction pressure. High electrochemical performance can be achieved if the compaction pressure is decreased and the operating temperature is increased because of hydrogen spillover during the operation.

Entropy Generation Analysis of Power-Law Non-Newtonian Fluid Flow Caused by Micropatterned Moving Surface

In the present study, the first and second law analyses of power-law non-Newtonian flow over embedded open parallel microchannels within micropatterned permeable continuous moving surface are examined at prescribed surface temperature. A similarity transformation is used to reduce the governing equations to a set of nonlinear ordinary differential equations. The dimensionless entropy generation number is formulated by an integral of the local rate of entropy generation along the width of the surface based on an equal number of microchannels and no-slip gaps interspersed between those microchannels. The velocity, the temperature, the velocity gradient, and the temperature gradient adjacent to the wall are substituted into this equation resulting from the momentum and energy equations obtained numerically by Dormand-Prince pair and shooting method. Finally, the entropy generation numbers, as well as the Bejan number, are evaluated. It is noted that the presence of the shear thinning (pseudoplastic) fluids creates entropy along the surface, with an opposite effect resulting from shear thickening (dilatant) fluids.

Large-Scale Solar-Assisted Water Heater for a Green Hospital

Concerns over the environmental impact of the high usage of fossil fuels to heat water in public, residential, commercial, and industrial sectors have triggered increased interest in solar energy. Hospitals and hotels utilize large amounts of energy in water heating. A case study of one such facility was conducted at the National University of Malaysia Hospital (HUKM). At the hospital, large amounts of LPG were consumed by two boilers resulting in the release of considerable amounts of greenhouse gases. A solar water heater (SWH) was designed and integrated with existing LPG burners to develop a hybrid SWH system. The SWH system is composed of 144 U-type pipe evacuated solar panels divided into three blocks. Each block consists of 12 strings of panels connected in parallel, with each string comprising 4 panels. In 2012, the annual average solar irradiation in Kuala Lumpur was 4.5 kW/m2/day. TRNSYS simulation software was used to predict the SWH performance before the design was finalized. Energy savings were expected to reach 60% based on the results of a simulation. However, 51% of LPG was saved according to data recorded throughout 2012. Solar water heating has promising industrial applications such as heat processing in textile factories, food processing, animal husbandry, dairy processing, aquaculture, swimming pool heating, and industrial and manufacturing facilities, with 59.9% annual average energy efficiency and 5.0% annual average exergy efficiency.

Recent Advances in Air-Based Bifacial Photovoltaic Thermal Solar Collectors

Bifacial photovoltaic (PV) solar cells offer additional radiation absorption by back surface of the solar cells, which is a significant advantage over ordinary photovoltaic (PV) monofacial solar cells. There are varieties of terrestrial applications for bifacial PV panels and bifacial photovoltaic thermal (PVT) solar collects such as building facade integration, window integration, fence/barrier integration, parking lot integration, etc. Bifacial PV panels provide shading and faint light penetration. This chapter describes the recent studies and advances on bifacial PV panels and bifacial photovoltaic thermal collectors for simultaneous production of electricity and hot air.

Characterization of Air-Based Photovoltaic Thermal Panels with Bifacial Solar Cells

Photovoltaic (PV) panels account for a majority of the cost of photovoltaic thermal (PVT) panels. Bifacial silicon solar panels are attractive for PVT panels because of their potential to enhance electrical power generation from the same silicon wafer compared with conventional monofacial solar panels. This paper examines the performance of air-based bifacial PVT panels with regard to the first and second laws of thermodynamics. Four air-based bifacial PVT panels were designed. The maximum efficiencies of 45% to 63% were observed for the double-path-parallel bifacial PVT panel based on the first law of thermodynamics. Single-path bifacial PVT panel represents the highest exergy efficiency (10%). Double-path-parallel bifacial PVT panel is the second preferred design as it generates up to 20% additional total energy compared with the single-path panel. However, the daily average exergy efficiency of a double-path-parallel panel is 0.35% lower than that of a single-path panel.