• Energy Research

This paper evaluates the performance of a recently patented rotationally asymmetrical dielectric totally internally reflective concentrator (RADTIRC) under diffuse radiation. The RADTIRC has a geometrical concentration gain of 4.969 and two half acceptance angles of ± 30° and ± 40° along the x-axis and z-axis respectively. Simulation and experimental work have been carried out to determine the optical concentration gain under diffuse radiation. It was found that the RADTIRC has an optical concentration gain of 1.94 under diffuse irradiance. The experimental results for the single concentrator showed an optoelectronic gain of 2.13, giving a difference of 9.8% due to factors such as the presence of direct radiation during experiments, the increase in diffuse radiation due to the reflection from surrounded buildings as well as from the ground reflection.

Making housing carbon neutral is one of the European Union (EU) targets with the aim to reduce energy consumption and to increase on-site renewable energy generation in the domestic sector. Optical concentrators have a strong potential to minimise the cost of building integrated photovoltaic (BIPV) systems by replacing expensive photovoltaic (PV) material whilst maintaining the same electrical output. In this work, the performance of a recently patented optical concentrator known as the rotationally asymmetrical dielectric totally internally reflective concentrator (RADTIRC) was analysed under direct and diffuse lightconditions. The RADTIRC has a geometrical concentration gain of 4.969 and two half acceptance angles of ±40 and ±30 respectively along the two axes. Simulation and experimental work has been carried out to determine the optical concentration gain and the angular response of the concentrator. It wasfound that the RADTIRC has an optical concentration gain of 4.66 under direct irradiance and 1.94 under diffuse irradiance. The experimental results for the single concentrator showed a reduction in concentration gain of 4.2% when compared with simulation data.

The race towards achieving a sustainable zero carbon building has spurred the introduction of many new technologies, including the BIPV (building integrated photovoltaic) system. To tackle the high capital cost of BIPV systems, LCPV (low-concentration photovoltaic) technology was developed. Besides the reductionof cost, the LCPV technology also produces clean energy for the building and promotes innovative architectural design. This paper presents a novel type of concentrator for BIPV systems. This concentrator, known as the RADTIRC (rotationally asymmetrical dielectric totally internally reflecting concentrator), wasincorporated in a small double glazing window. The RADTIRC has a geometrical concentration ratio of 4.9069x. A series of experiments were carried out to evaluate the performance of the solar PV window both indoors and outdoors. It was found that the RADTIRC-PV window increases the short circuit currentby 4.13x when compared with a non-concentrating solar PV window. In terms of maximum power generation, the RADTIRC-PV window generates 0.749 W at normal incidence, 4.8x higher than the nonconcentrating counterpart.

Portable solar chargers have been gaining popularity as a new technology to help increase electrification in rural areas in developing countries. It is a fast developing industry aiming to produce a low-cost solution for the application of off-grid solar lighting and charging of small devices to be used by the poorestand most vulnerable of society. Solar concentrators are proposed as an add-on to help further reduce costs, to increase light-output hours and to reduce charging time. So far, no suitable concentrator designs have been proposed. This paperpresents a novel concept for the design of a static nonimaging concentrator, suitable for portable solar systems for developing countries. The novel concentrator design is compared with existing concentrators and its suitability for portable solar chargers, as well as its potential for further improvement, arehighlighted.

This paper focuses on the embodied energy and cost assessments of a static concentrating photovoltaic (CPV) module in comparison to the flat photovoltaic (PV) module. The CPV module employs a specific concentrator design from the Genetically Optimised Circular Rotational Square Hyperboloid (GOCRSH) concentrators, labelled as GOCRSH_A. Firstly, it discussed previous research on life cycle analyses for PV and CPV modules. Next, it compared the energy embodied in the materials of the GOCRSH_A module to the energy embodied in the materials of a flat PV module of the same electrical output. Lastly, a comparison in terms of cost is presented between the analysed GOCRSH_A module and the flat PV module. It was found that the GOCRSH_A module showed a reduction in embodied energy of 17% which indicates a reduction in embodied carbon. In terms of cost, the costs for the GOCRSH_A module were calculated to be 1.71 times higher than the flat PV module of the same electrical output. It is concluded that a trade-off is required between the embodied energy and cost impacts in order to bring this CPV technology into the market.

The present global energy scenario, in which fossil fuels play a preponderant role, faces significant energy and environmental challenges. To help address these challenges, countries across the world are increasing the contribution made by renewable energy (RE) resources to their energy supplies. Feed-in Tariff (FiT) is one of the most effective incentive policies used to promote the RE sector especially at the micro-generation level. The key objective of the FiT schemes is to provide financial support to residential, industrial and commercial consumers to encourage them to become RE producers. Solar photovoltaic (PV) is one of the most promising RE technologies. This paper provides an overview of the solar PV developments in the Association of South East Asian Nation (ASEAN) countries. It reflects upon the RE trends in the world as well as providing an introduction to the ASEAN countries. It reviews the progress of solar PV in each of the ASEAN countries especially in terms of RE policies, growth in terms of PV installations and research and development activities. Finally, the paper presents conclusions and a set of recommendations. Out of the 10 ASEAN countries, 5 have implemented FiT as a key policy incentive to stimulate the progress of RE. It is found that the ASEAN countries have great potential for solar PV in term of their annual solar insolation levels, which ranging from 1460 to 1892 kWh/m2 per year.

Building integrated photovoltaic (BIPV) systems have been proposed to make solar photovoltaic systems more attractive. These systems are not only capable of generating electricity, but can also contribute to minimise energy consumption in buildings by providing natural illumination, space and water heating, ventilation and shading. Despite these advantages, one of the issues that still prevents the widespread adoption of BIPV systems is their high capital cost. This paper discusses a novel type of non-imaging optical concentrator that can be used to reduce the capital cost of a BIPV system. This new concentrator, known as rotationally asymmetrical compound parabolic concentrator (RACPC), has a flat entrance aperture that facilitates integration within a double-glazing window and reduces fabrication costs. The RACPC, which has a geometrical concentration of 3.66x, also offers other advantages over conventional solar concentrators: suitability for fenestration, ease of integration with square PV cells, and passive tracking. Several experiments were carried out on a double-glazing solar window incorporating an array of 4x3 concentrator-PV cells. The experiments were carried out indoors under standard test conditions. The results show that the RACPC-PV window effectively increases the short-circuit current by a factor of over 3 at normal incidence when compared with a non-concentrated solar window. The solar window also shows an increase in maximum power generation by a factor of nearly 3.