Assessment of PV Shading Device on Building Energy Consumption Taking into Account Site Layout

This paper presents the results of a combined study of building energy consumption and the electricity production from PV modules integrated into a shading device, taking account of different site layouts. Various combinations of surrounding building configurations and the tilt angles of the shading device （that determines the PV module orientation） are examined.

Guidelines for Sizing Shading Devices for Typical Residential Houses in Muscat, Oman

Energy consumption of Oman＇s building sector is around 55% of the country＇s total energy demand and it has increased by 59% from 2005 to 2010. This paper investigates the potential of energy conservation in residential buildings in the city of Muscat by providing guidelines to reduce solar gain in overheated season. It aims to identify the problem of high energy consumption in modem houses and study the relationship between energy consumption and thermal performance of the building. Based on the authors＇ analysis of Oman＇s solar data, recommendations for shading devices were developed and evaluated using e-QUEST. An energy reduction of around 10% was achieved without drastically increasing the cost of construction while also taking into consideration of society＇s requirement for privacy and its concern to visually maintain cultural identity.

DECISION-MAKING FRAMEWORK FOR SELECTION AND DESIGN OF SHADING DEVICES BASED ON DAYLIGHTING

This research looked to improve the daylighting performance of a shading device as a window component.The paper describes the development of the decision-making framework(DMF)for the selection and design of shading devices based on daylighting.The DMF presents the process of analysis of the shading devices’daylighting performance in the selection of existing shading devices and in the design of new shading devices.The research determined the shading device daylighting performance measures(such as illuminance and daylight autonomy)as well as the variables that influence daylight performance.Interactions among the variables and the effects of these interactions on the shading device daylighting performance were explained and quantified in the DMF.The DMF also included ways of present-ing the results of testing the shading devices and the process of making the decision.A case study for three blind systems was performed to determine if the DMF provides a concept for the analysis of the daylighting performance of shading devices and for making decisions about the design/selection of the shading device.Computer simulation was used to calculate the illuminance levels and the daylight autonomies(DAs)as a result of the application of these blinds.The values of the DAs are compared for three blind systems to select the most appropriate sys-tem to be applied on a proposed building.The DMF based on daylighting can help building designers to select the most suitable shading device based on its daylighting performance,and can help shading device manufacturers in designing new shading devices with improved daylighting performance.FIGURE 2.Simplified DMF diagram.

ENVIRONMENTAL DAMAGE AND SAVING BENEFIT OF EXTERNAL SHADING DEVICES VIA PHOTOVOLTAIC (PV) ENERGY GENERATION

The aim of the study is to evaluate both environmental damage and saving benefit in selecting building shading devices.The environmental damage from the produc-tion and construction(P&C)of shading devices is evaluated.The saving benefit,i.e.,decreasing building operation energy(OE),due to installing shading devices is evaluated.A simple office building module is used.The external shading devices are constructed from concrete-based external shading devices and aluminum-based light shelf devices.Energy design via Life Cycle Energy Assessment(LCEA)and environmental design via Life Cycle Assessments(LCA)are applied.Environmen-tal design is performed when PV energy generation is used.It was found that in energy design,40%of building OE saving benefit is required to compensate energy needed for the P&C of shading devices.In environmental design,100%of the building OE saving benefit is required to compensate for environmental damage stemming from the P&C of shading devices.It was concluded that in energy design,in addition to OE,P&C energy should be evaluated.In environmental design,due to a major reduction in the OE saving benefit,the importance of the P&C environmental damage increased.Environmental design cannot be replaced with energy design when PV energy generation is assumed for building OE needs.

ENHANCING THE DAYLIGHT AND ENERGY PERFORMANCE OF EXTERNAL SHADING DEVICES IN HIGH-RISE RESIDENTIAL BUILDINGS IN DENSE URBAN TROPICS

This study examines the daylight and energy performance of 27 external shading scenarios in a high-rise residential building in the urban tropics.The cooling energy,daytime lighting energy and the spatial daylight autonomy(sDA)of the building model were simulated in Rhino3D and Grasshopper simulation software.The best per-formance scenario(vertical and horizontal shading on the twentieth floor,horizontal shading only for the eleventh floor and no shading for the second floor)satisfied 75 sDA(300lx|50)with corresponding annual enery performance of 16%-20%in the cardinal directions.The baseline scenario,which is the current practice of providing balconies on all floors,reduced daylight to less than 75 sDA on the eleventh and second floor,even though it had higher annual enery performance(19%-24%)than the best performance scenario.Application of the design principles to a case study indicated that 58%of the spaces had over 75 sDA for both Baseline and Best per-formance scenarios,while an increase in enery performance of 1%-3%was found in the Best performance scenario compared to the Baseline.

A design framework for a kinetic shading device system for building envelopes

This paper presents a design framework of a shading device applied on a building envelope,with a scheduled automatic activation logic,based on a sun path diagram.This proposal aims to balance the direct sun indoor exposure by evaluating the envelope area exposed to direct sun rays and the hourly activation rate of shading devices.These procedures are over the parametric modeling and simulation platform using raytracing,structural finite element analysis,and Computer Numerical Control(CNC)prototyping.The design process of building envelopes equipped with kinetic devices can use all these design resources.The kinetic device’s activation logic relies on the feed-forward paradigm,scheduling the activation from the parametric modeling and the sun path diagram,using an angle threshold between the device post and the sun vector as a parameter.The design framework showed the preliminary path to develop shading devices considering the building envelope shape with a feedforward activation logic based on local sun path characteristics.

DETERMINING THE EFFECT OF BUILDING GEOMETRY ON ENERGY USE PATTERNS OF OFFICE BUILDINGS IN TORONTO

The project investigated the potential of building geometry to minimize energy consumption in office buildings.Five distinct geometries were modeled as mid-size office occupancies in the context of Toronto,Ontario,and examined with varied design parameters:window to wall ratio(WWR)and external static shading devices.IES VE software was used to predict the annual energy consumption of the five archetypes for 40 permutations.The outcome of this research showed that the variation of the total energy use from one shape to another was relatively small.WWR appeared to have a stronger impact on the energy pattern of a building than its shape.Overall,the energy performance of the archetypes were observed to conform to their individual building aspect ratios.The findings are thus expected to provide useful guidelines for architects on utilizing building geometry as an energy saving measure in the design of office buildings.

FAÇADE DESIGN EFFECT ON CROSS-VENTILATION IN Taiwan Residents SCHOOL BUILDINGS

This study performed a three-dimensional numerical prediction for the induced airflow patterns and mean age of air(MAGE)around and inside a naturally ventilated school building,while accounting for the wind profile effect.Various fenestrations,hallways,and shading devices on the windward side of building were analyzed to determine how they affected wind velocity,the incident angle of airflow,and MAGE distribution inside classrooms.The numerical scheme is based on a commercial computational fluid dynamics(CFD)code,PHOENICS.The incline of incoming wind was observed on higher floors that decreased the air exchange rate in the simulated room.The inclined airflow could be effectively deflected downward through the breathing zone by hallways,1.2-m shades as overhangs,and 0.6-m louvers.Based on this research,an appropriate combination of external attachments on the windward side of building façade can be utilized to enhance ventilation in school buildings.(See Appendix 1 for nomenclature.)

Using passive cooling strategies to improve thermal performance and reduce energy consumption of residential buildings in U.A.E. buildings

Passive design responds to local climate and site conditions in order to maximise the comfort and health of building users while minimising energy use. The key to designing a passive building is to take best advantage of the local climate. Passive cooling refers to any technologies or design features adopted to reduce the temperature of buildings without the need for power consumption. Consequently, the aim of this study is to test the usefulness of applying selected passive cooling strategies to improve thermal performance and to reduce energy consumption of residential buildings in hot arid climate settings, namely Dubai, United Arab Emirates. One case building was selected and eight passive cooling strategies were applied. Energy simulation software namely IES was used to assess the performance of the building. Solar shading performance was also assessed using Sun Cast Analysis, as a part of the IES software. Energy reduction was achieved due to both the harnessing of natural ventilation and the minimising of heat gain in line with applying good shading devices alongside the use of double glazing. Additionally, green roofing proved its potential by acting as an effective roof insulation. The study revealed several significant findings including that the total annual energy consumption of a residential building in Dubai may be reduced by up to 23.6% when a building uses passive cooling strategies.

Architectural quality of the productive facades integrating photovoltaic and vertical farming systems: Survey among experts in Singapore

Buildings could play a critical role in energy and food production while making highdensity cities more resilient.Productive facades(PFs),as flexible and multi-functional systems integrating photovoltaic(PV)and vertical farming(VF)systems,could contribute to transforming buildings and communities from consumers to producers.This study analyses the architectural quality of the developed PF concept drawing on the findings of a web-survey conducted among experts e building professionals in Singapore.The developed design variants are compared with regards to key design aspects such as facade aesthetics,view from the inside,materialisation,ease of operation,functionality and overall architectural quality.The study also compares and discusses the results of the web-survey with the results of a previously conducted door-to-door survey among the potential users-residents of the Housing&Development Board(HDB)blocks.The findings confirm an overall acceptance of the PF concept and reveal a need for synergetic collaboration between architects/designers and other building professionals.Based on the defined PF design framework and the results of the two surveys,a series of recommendations and improved PF prototypes are proposed for further assessment and implementation in order to foster their scalability from buildings into communities and cities.