Brian Norton

Review of solar-energy drying systems II: an overview of solar drying technology

A comprehensive review of the various designs, details of construction and operational principles of the wide variety of practically-realised designs of solar-energy drying systems reported previously is presented. A systematic approach for the classification of solar-energy dryers has been evolved. Two generic groups of solar-energy dryers can be identified, viz passive or natural-circulation solar-energy dryers and active or forced-convection solar-energy dryers (often referred to as hybrid solar dryers). Three sub-groups of these can also be identified, viz integral-type (direct mode), distributed-type (indirect mode) and the mixed-mode type. The appropriateness of each design type for application by rural farmers in developing countries is discussed. Some very recent developments in solar drying technology are highlighted.

Life-cycle operational and embodied energy for a generic single-storey office building in the UK

Increasing energy efficiency makes embodied energy considerations increasingly significant. The energy initially embodied in a building could be as much as 67% of its operating energy over a 25-year period. If additional embodied energy gained over the building life is also included, the total life-cycle energy could be larger than the operating energy over the same period. Currently, embodied energy cannot be predicted accurately due to lack of reliable and accurate data; there is a wide variation in the data available. The variation of life-cycle operational and embodied energy and capital cost as a function of building parameters is explored.

Review of solar-energy drying systems III: low temperature air-heating solar collectors for crop drying applications

Abstract The efficient design and construction of solar-energy air-heating collectors are critical to the overall performance of the distributed (indirect mode) and mixed-mode designs of either active or passive solar-energy crop dryers. A review of the various designs and the performance evaluation technique of flat- plate solar-energy air-heating collectors for low temperature (i.e. temperature elevations between 10°C–35°C above ambient) solar-energy crop drying applications are presented. The appropriateness of each design and the component materials selection guidelines are highlighted.

Linear Dielectric Non-Imaging Concentrating Covers For PV Integrated Building Facades

A three-dimensional optical analysis of two dielectric, non-imaging concentrating covers for building integrated photovoltaics shows that an asymmetric concentrator is more suitable for use at building facades. For a wide range of solar incidence angles, optical efficiencies are over 90% for both concentrators. The optimum collection tilt angle for two different latitudes and the monthly and annual collected solar energy for both concentrators are predicted and compared to flat photovoltaic covers of the same photovoltaic and aperture area. Employing high transmittance materials for dielectric concentrating covers enables such refractive systems to achieve high solar energy acceptance thus requiring less photovoltaic material thereby reducing initial capital cost.

The effect of tank geometry on thermally stratified sensible heat storage subject to low Reynolds number flows

In a theoretical and experimental investigation into the thermal performance of stratified hot water stores, a transient three-dimensional finite-volume based model was validated by comparison with measured temperatures from a series of thirty-two experiments in which the inlet velocities, temperatures and initial store stratification profiles were varied. A parametric analysis ascertained the effect of inlet and outlet port locations on store performance for a range of operating conditions. The effects of finite volume size on predicted levels of entrainment and diffusion in the inlet region are reported.

Validated, unified model for optics and heat transfer in line-axis concentrating solar energy collectors

A rigorous numerical simulation model for the prediction of the combined optical and thermofluid behaviour of line-axis concentrating solar energy collectors combines two-dimensional steady-state finite element analysis of convective heat transfer and ray-trace techniques. The optical analysis considers both direct and diffuse insolation components and is therefore useful for the analysis of compound parabolic concentrating collectors. Experiments using Mach-Zehnder interferometry indicate a parametric range for which such a two-dimensional representation is valid.

Solar energy thermal technology

The solar energy resource transmission of solar energy through transparent materials absorption of solar energy at surfaces flat plate collectors line-axis concentrating collectors solar ponds solar dryers solar refrigeration greenhouses passive and active solar design of buildings.

A comparative performance rating for an integrated solar collector/storage vessel with inner sleeves to increase heat retention

Abstract Integral Collector/Storage (ICS) solar water heating systems suffer substantial heat loss during periods of low insolation or at night. Methods to reduce aperture heat loss include moveable insulated lids/shutters, transparent insulating glazing materials and selective glazing/absorber coatings. All of these approaches involve trade-offs with reduction in performance and/or an increase in cost. A novel ICS vessel design to mitigate heat loss is proposed. An ICS vessel utilising an inner sleeve arrangement is shown to reduce heat loss by up to 20%. This paper examines four inner sleeve design configurations, several of which demonstrate an increase in the heat retention capability over existing vessels, and an optimised design is presented.

Quantum dot solar concentrator behaviour, predicted using a ray trace approach

SYNOPSIS Using a three-dimensional raytrace technique, a model to optimise the design of Quantum Dot Solar Concentrators for photovoltaic applications has been developed. The model includes reflection, refraction and absorption of solar radiation allowing the prediction of the optical efficiency. The optical efficiency is defined as the energy emitted from the selected edge or edges divided by the solar energy incident on the material. Using the model, a parametric analysis was performed and the optical properties of a selected system optimised. Details of the model and predictions of concentrator efficiency and ray path lengths for a range of quantum dot seeding levels are shown. The effects of path length on energy absorbed in the carrier material and that reaching the photovoltaic material are presented.

Integration of Microstrip Patch Antenna With Polycrystalline Silicon Solar Cell

The implementation of a polycrystalline silicon solar cell as a microwave groundplane in a low-profile, reduced-footprint microstrip patch antenna design for autonomous communication applications is reported. The effects on the antenna/solar performances due to the integration, different electrical conductivities in the silicon layer and variation in incident light intensity are investigated. The antenna sensitivity to the orientation of the anisotropic solar cell geometry is discussed.