SOLAR ARCHITECTURE AND ENERGY ENGINEERING

The modern built environment has been developed in a context of readily-available,low-cost energy from highly concentrated fossil fuels.Today’s global energy landscape has dramatically changed;energy costs have become significant in the operation of buildings,and the sector uses a major portion of the global resources of fossil fuels.In recent years a major focus of green building development in North America and internationally has been on setting up sustainable energy practices for the built environment.This focus has advanced energy conservation and efficiency measures for buildings;on-site clean energy generation is now positioned as a critical next step in meeting increasing energy demands while enhancing the functionality and comfort of buildings.“Solar Architecture”as a green building concept addresses sustainable energy practices and the needs of the three major tiers of the built environment:community planning,existing buildings,and new construction.This article uses a case study of integrating renewable energy engineering into university campus energy planning to demonstrate some of the roles energy engineering plays in our built environment.As part of a master planning process for Dalhousie University,solar energy generation potential mapping and the SolarStarRating™system were used to facilitate the integration of solar technologies into the community energy mix.The process identified the buildings most suited to retrofitting with solar technologies,and enabled the best opportunities to be investigated.

APPLICATION OF LIFE CYCLE ASSESSMENT TO VARIOUS BUILDING LIFETIME SHEARING LAYERS:SITE,STRUCTURE,SKIN,SERVICES,SPACE,AND STUFF

Currently,green rating systems are not directly related to environmental conse-quences.Moreover,rating systems score both building-related tasks with long life-time expectancies and system-related tasks with short lifetime expectancies without separating them.Therefore,passive solar and bio-climatic architectures,which have long lifetime expectancies and thus have a strong,negative impact on the environ-ment,are neglected.The main goal of this study is to explore differences in total environmental impact for a single“typical”building module(with the heavy wall building technology accepted in Israel)in terms of six different lifetime shearing layers,Site,Structure,Skin,Services,Space Plan,and Stuff,each of which reflects a different form of environmental damage.The objective of this study was to evalu-ate the six shearing layers using life cycle assessment(LCA)by applying Eco-indi-cator 99(EI99).It was found that the environmental damage associated with the Building layers(Site,Structure,and Skin)was higher than that associated with the Service layers(Services,Space Plan,and Stuff).The paper may contribute to the development of a more scientific(quantitative)background for green rating systems.As a result,a greater decrease in building-related ecological impacts can be achieved,thus encouraging sustainable building activities.

Comparative architecture in monolithic perovskite/silicon tandem solar cells

Inorganic-organic metal halide perovskite light harvester-based perovskite solar cells(PSCs)with widely tunable bandgap have achieved rapid growth in power conversion efficiency,which exceeds 25%now.It is deliberated that if a semitransparent solar cell made of wider bandgap materials was placed on top of a narrow bandgap materials-based solar cell such as a silicon solar cell,with proper optical and electrical arrangements,the resultant tandem device consisting of two subcells could more effectively utilize the solar spectrum than a single junction solar cell.In a perovskite/silicon tandem solar cell(PSTSC),a semitransparent PSC with a wider bandgap is placed on top of a narrow bandgap silicon solar cell.The PSC efficiently harvests the higher energy photons in the ultraviolet and visible regions of the solar spectrum while the silicon solar cell can convert the photons of the infrared region to power.The PSTSC is proposed as a potential candidate to overcome the Shockley-Queisser limit of single-junction silicon solar cells.Though the theoretical limit of a PSTSC is calculated as~42%,its actual efficiency achieved until now is less than 30%.Therefore,a great scope of research exists in improving the efficiency of PSTSCs.Current issues of stability and upscaling of the device in PSCs are also a matter of concern for PSTSCs.A tandem device consists of multiple parts,and different configurations can be applied,thus tuning the architecture of the device.Altering various parts may result in significant changes in the efficiency of the device.In this review,competing architectures of otherwise comparable devices are compared in terms of photovoltaic properties.Thus,future directions to improve the efficiency of the device based on architecture design are proposed herein.In particular,the influence of the polarity of PSCs and the surface morphology of silicon solar cells(both front and rear)on determining the properties of the PSTSC are discussed.