A Review of Daylighting System: For Prototype Systems Performance and Development

Mean wavelength-based Fresnel lens solar collector for eliminating the hotpot problem in daylighting systems

In this paper, the mean-wavelength-based Fresnel lens was designed by merging the modified edge ray principle and idea of superposition. The bottom-to-top approach optimizes the design of individual prisms according to the predetermined plastic optical fiber (POF) bundle size. The simulated optical efficiency of the collector for the sun's visible spectrum (380-740 nm) light is 82.93% with a uniformity ratio of 0.434. Based on the designed collector, the daylighting system can deliver 199.38 lumens via a 10 m long POF bundle with an efficiency of 23.78%. The thermal analysis revealed that the maximum temperature on the focus plane was 49.7°C.

Energy Saving Strategies and On-Site Power Generation in a University Building from a Tropical Climate

This paper compares the potential for building energy saving of various passive and active strategies and on-site power generation through a grid-connected solar photovoltaic system (SPVS). The case study is a student welfare unit from a university campus located in the tropical climate (Aw) of Guayaquil, Ecuador. The proposed approach aims to identify the most effective energy saving strategy for building retrofit in this climate. For this purpose, we modeled the base line of the building and proposed energy saving scenarios that were evaluated independently. All building simulations were done in OpenStudio-EnergyPlus, while the on-site power generation was carried out using the Homer PRO software. Results indicated that the incorporation of daylighting controls accounted for the highest energy savings of around 20% and 14% in total building energy consumption, and cooling loads, respectively. Also, this strategy provided a reduction of about 35% and 43% in total building energy consumption, and cooling loads, respectively, when combined with triple low-e coating glazing and active measures. On the other hand, the total annual electric energy delivered by the SPVS (output power converter) was 66,590 kWh, from where 48,497 kWh was supplied to the building while the remaining electricity was injected into the grid.