Experiment and simulation to determine the optimum orientation of building-integrated photovoltaic on tropical building façades considering annual daylight performance and energy yield

Building-Integrated Photovoltaic(BIPV)on vertical façades is a potential PV application in today’s buildings.The performance of BIPV on façades is significantly influenced by the façade orientation.For tropical cities,the optimum façade orientation,in terms of maximum energy yield and daylight performance,cannot be simply determined,due to relatively symmetrical sun path throughout the day.This study therefore aims to determine the optimum orientation for BIPV on tropical building façades.To achieve the objective,experiment,modelling,and computational simulation are conducted to evaluate the BIPV energy yield and to predict the indoor daylight performance in a scale-model building with a 105Wp monocrystalline silicon PV,facing each cardinal orienta-tion in Bandung,Indonesia.The South orientation yields practically zero ASE_(1000,250),providing the best annual daylight performance,and yielding the most desirable value in four out of five daylight metrics.The greatest annual energy yield is at the North orientation,providing 179-186 kWh(95%prediction interval)per year,but with larger uncertainty compared to that at the South,due to direct sunlight occurrence.Based on three different objective functions,the South orientation is considered optimum for placing the BIPV panel on the prototype façade in the location.

Design optimisation of mean room surface exitance and total corneal illuminance using Monte Carlo simulation

In lighting design,mean room surface exitance(MRSE)has been known as an indicator of the adequacy of illumination in an indoor space.Recent studies have suggested an exponential model relating MRSE and the observer’s retinal response.This is particularly applicable in a room with homogenous room surface reflectance and a constant total corneal illuminance,which is the total illuminance received at the eye.However,accuracy of the exponential model is yet to be assessed in detail.Furthermore,the implication on interior lighting design is also yet to be quantified.This study thus aims to assess the accuracy of the exponential model and to optimise the output variables.Random computations using Monte Carlo simulation are performed for various input variables,followed with sensitivity and uncertainty analyses and optimisation.Prediction errors of the exponential model are found between-10%and 6%.The MRSE is highly influenced by surface reflectance,whereas the total corneal illuminance is influenced by the source luminous flux.Optimum design parameters are obtained by minimising the ratio between total corneal illuminance and MRSE.Overall,this study provides guidelines in lighting design practice for enhancing room spatial brightness while minimising energy use.