1、2010 ASHRAE 461ABSTRACTA general simulation design methodology for integrateddaylighting and thermal analysis of perimeter spaces of build-ings is presented in this paper. The objective is to provideguidelines on how to select glass ratio of the faade, shadingdevice properties and control from the e
2、arly design stage. Thesimulation-based approach followed is to create generalizedperformance indices (at a systems level) as parametric func-tions of key design parameters (at a component level, such asthe glazing area) and then provide the designer with usefulinformation for making decisions based
3、on the integrated anal-ysis results. Integrated performance indices, obtained by thecontinuous interaction between hourly coupled thermal andlighting simulation, are used as major initial criteria for theselection of fenestration and shading design schemes, based onthe balance between daylighting re
4、quirements and the need toreduce solar gains. The methodology is general and applies toperimeter spaces of commercial and institutional buildings(particularly offices) for any location, orientation, glazing andshading type.INTRODUCTIONDuring the conceptual design stage of a building, thedesign team
5、often has to make critical decisions with signifi-cant impact on the energy performance and indoor comfortconditions. The design and control of facades and fenestrationsystems has a major impact on building performance, espe-cially for perimeter spaces of commercial and institutionalbuildings. With
6、the growing interest in energy-consciousdesign and solar architecture, the importance attached todaylight utilization has grown; nowadays, daylighting iswidely accepted as a necessity for commercial buildings.Daylight utilization can improve lighting quality (Selkowitz1998), increase occupants produ
7、ctivity (Heschong 2002;Nicol et al. 2006) and effectively reduce electricity consump-tion for lighting (Lee et al. 1998; Tzempelikos et al. 2007).Nevertheless, the balance between positive and negativeimpact of solar radiation on building overall energy perfor-mance and human comfort should be taken
8、 into account at theearly design stage. Glazed facades often create problems suchas glare, thermal discomfort and overheating. Peak heatingand cooling loads could increase significantly, depending onthe window size and properties, climate and orientation- therole of thermal mass is also critical (Ba
9、laras 1996). For allthese reasons, many innovative fenestration and shadingsystems have been developed and studied in order to controlsolar gains, reduce glare and create a high quality indoor envi-ronment. Unfortunately, the optical and thermal properties ofsuch systems are not usually provided by
10、the manufacturersand they have to be estimated using experimental techniques(Rosenfeld et al. 2001; Andersen et al. 2005; Collins et al.2001), using complex theoretical models (Pfrommer et al.1996; Tsangrassoulis et al. 1996) or even advanced software(Reinhart and Walkenhorst 2001).Moreover, recent
11、developments in dynamic buildingenvelope technologies (e.g. airflow windows, integratedphotovoltaic systems) have created new opportunities toachieve significant savings in building energy, peak demand,and cost, while aiming for enhanced occupant satisfaction.Transparent building facades are evolvin
12、g. Coupled with elec-tric lighting control systems, dynamic envelope and lightingsystems can be actively controlled on small time steps toreduce the largest contributors to commercial building energyIntegrated Design of Perimeter Zones with Glass FacadesAthanassios Tzempelikos, PhD Andreas K. Athien
13、itis, PhD, PE Antonis Nazos, PEAssociate Member ASHRAE Member ASHRAEA. Tzempelikos is an assistant professor of Architectural Engineering in the School of Civil Engineering, Purdue University, West Lafayette,IN. A.K. Athienitis is a professor and research chair in the Department of Building, Civil a
14、nd Environmental Engineering, Concordia Univer-sity, Montreal, Quebec, Canada. A. Nazos is an instructor at the School of Mechanical Engineering, Technological Education Institute ofPiraeus, Athens, Greece.OR-10-049 2010, American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc
15、. (www.ashrae.org). Published in ASHRAE Transactions 2010, Vol. 116, Part 1. For personal use only. Additional reproduction, distribution, or transmission in either print or digital form is not permitted without ASHRAEs prior written permission. 462 ASHRAE Transactionsconsumption: lighting and cooli
16、ng (air conditioning) (Tzem-pelikos et al. 2007).The building design team may choose from a wide varietyof design options, for many of which the evaluation of theirimpact on building performance is difficult or even impossi-ble. Inevitably, the selection of final design solutions ofteninvolves many
17、subjective factors. Since the faade and fenes-tration design relates to different aspects of building perfor-mance (heating, cooling, lighting, ventilation) and humancomfort (thermal, visual), an integrated approach should befollowed starting from the early design stage. Citherlet et al.(2001) point
18、ed out the significance of integration in buildingphysics simulation. The identification of the need for detailedsimulation programs that integrate thermal and daylightingperformance (Selkowitz 1998) resulted in efforts to coupledaylighting and thermal simulation (Franzetti at al. 2004). Asignifican
19、t step was the development of performance indicesfor glazing systems based on integrated simulation Citherletand Scartezzini (2003). A prototype method for design opti-mization of glazing performance was presented by Johnson etal (1984). In an integrated lighting and thermal simulationstudy with emp
20、hasis on the comfort aspect (Laforgue et al.1997), the window transparency is identified as the linkbetween thermal and visual performance. More recently, amore complete parametric study (Gratia and De Herde 2003)set the basis for design of low energy office buildings.However, the impact of dynamic
21、shading operation onbuilding performance is generally not taken into accountduring the design stage, although an optimum balancebetween cooling and lighting requirements may be identifiedand utilized, considering fenestration and daylighting param-eters (Lee and Selkowitz 1995; Tzempelikos and Athie
22、nitis2005, 2007). Herkel (1997) acknowledged shading control asan important interactive link between daylighting and thermalsimulation. A significant effort to identify the impact ofcontrol strategies was recently published (Moeseke et al.2007). Peak loads and energy demand for cooling and lightingc
23、an be reduced if shading operation is linked with simultane-ous control of electric lighting and HVAC components;provided that fenestration and shading properties and controlswill be selected based on their integrated impact on buildingenergy performance.The main obstacles towards achieving this tar
24、get are:(i) Design methods or software tools that focus on one do-main (e.g., daylighting or reduction in heating demand),although very useful and sophisticated sometimes, do notlook at the problem from a general perspectivefrom adesigners point of view. For example, Bouchlaghem(2000) developed a me
25、thod for optimizing building enve-lope design with respect to thermal performance only.Fernandes and Papamichael (2003) proposed a new meth-odology for automatic selection of fenestration systemproperties in order to satisfy daylighting requirementsonly.(ii) Most of the advanced building simulation
26、software areused to evaluate the overall energy performance of exist-ing buildings or in the design development stage, whenthe building form is already determined. And that isbecause detailed input data is usually required in order torun even the simplest simulation.Consequently, the selection of fi
27、nal design solutionsconcerning facades often involves many subjective factorsimposed by the design team at the early design stage. Thispaper presents a general simulation design methodology forintegrated daylighting and thermal analysis of perimeterspaces of buildings (excluding residential building
28、s). Theobjective is to provide guidelines on how to select glazed ratioof the faade, shading device properties and control at theearly design stage. Integrated performance indices, obtainedby the continuous interaction between transient hourly ther-mal and lighting simulation, are used as major init
29、ial criteriafor the selection of fenestration and shading design schemes.SIMULATION APPROACH AT THE EARLY DESIGN STAGEDuring the early design stage, the building geometry,characteristics and materials are still being formulated. There-fore the simulation approach should not be the analysis of aspeci
30、fic design solution, but the systematic exploration ofinter-related design alternatives, in order to provide the build-ing designer with a set of efficient design solutions. In general,there is less interest in finding “optimal” design solutions inthe strict sense of the word (Mahdavi 2004). Perform
31、ance-based design support environments can be used in a flexible,dynamic and iterative manner. Moreover, optimization meth-ods cannot be considered as design support tools, since theyonly compute optimal values. The objective of the designprocess is not generation of unique solutions; it should be a
32、multi-level integrated process.For perimeter spaces, the simulation procedure in theearly stage should be able to take into account daylighting andthermal parameters, link them in an integrated way, andprovide a method for quantitative and qualitative evaluation ofdesign options based on performance
33、-based measures. Sincefenestration systems are a key element when designing fordaylight, emphasis should be given on the selection and typeof analysis of fenestration. Driven by technological advancesin transparent building facades, design alternatives haveshifted to utilizing dynamic fenestration a
34、nd shading systemsfor optimal control of daylighting and solar gains. Therefore,different building system aspects (daylighting, electric light-ing, heating, cooling, shading) have to be considered in paral-lel when making early stage decisions. The transition fromcomponent-based simulation to a “sys
35、tems” approach is a keyissue for an integrated design process. Components, such asshading devices, can be modeled using one of the availablemethods. The effect of variation of the design variables onperformance-based parameters could give a more completepicture of design solutions. 2010, American So
36、ciety of Heating, Refrigerating and Air-Conditioning Engineers, Inc. (www.ashrae.org). Published in ASHRAE Transactions 2010, Vol. 116, Part 1. For personal use only. Additional reproduction, distribution, or transmission in either print or digital form is not permitted without ASHRAEs prior written
37、 permission. ASHRAE Transactions 463The following sections describe the general methodologydeveloped for daylighting and thermal simulation, the couplingbetween the two and the extraction of useful information basedon performance indices generated by the continuous interac-tion between the two domai
38、ns. An important requirement isutilization of hourly or sub-hourly data that will be used fordaily, monthly and yearly calculations. The simulation-basedapproach followed is to create generalized performance indices(at a systems level) as parametric functions of key designparameters (at a component
39、level, such as the glass area) andthen provide the designer with useful information for the selec-tion of the desired value based on the integrated analysisresults. The methodology presented in this paper applies toperimeter spaces of commercial and institutional buildings(particularly offices) for
40、any location, orientation, glazing andshading type.THEORETICAL BASIS FOR AN INTEGRATED THERMAL AND DAYLIGHTING METHODOLOGY DURING THE EARLY DESIGN STAGEEarly stage design of perimeter spaces is basically a sys-tems integration challenge, involving all parameters con-nected to integrated daylighting
41、and thermal performance.The complex interactions between fenestration system design,shading device properties and control, electric lighting con-trol, thermal parameters, human requirements, building orien-tation and climatic parameters have to be evaluated from thebeginning and provide feedback unt
42、il the final design.The key issue for coupling the two domains is to deter-mine a set of linking parameters which have an impact on boththe thermal and lighting performance of the space. The dy-namic interaction between lighting and thermal simulationcan then be described by investigating the relati
43、onship be-tween these linking parameters and the simultaneous impacton the two domains during the actual simulation process.Furthermore, a deeper exploration of dynamic linksbetween lighting and thermal performance leads to a distinc-tion between direct and secondary links. Direct links have animmed
44、iate impact both on the daylighting and the thermalperformance (e.g. amount of transmitted daylight and solarradiation). The following parameters were identified as directdynamic links between daylighting and thermal simulation:Window sizeWindow propertiesShading device type and propertiesShading de
45、vice controlSecondary links work like transfer functions. They trans-fer the dynamic effect of direct links on one domain to theother domain. For example, electric lighting control is asecondary dynamic link because, for a given set of direct links,it operates by reading data from the daylighting mo
46、dule anddynamically transfers the effect to the thermal module in theform of resulting internal gains (Figure 1).Finally, linking parameters are separated into continuousand discrete. For example, window size and properties arecontinuous parameters because simulation could run as a func-tion of diff
47、erent values. Shading type and control and electriclighting control are discrete parameters because they can takecertain values; in a way, they act like interactive boolean oper-ators during the simulation process.The interaction between the thermal and lighting simula-tion with the direct and secon
48、dary linking parameters is aniterative process. For instance, thermal and lighting simulationwill run considering a continuous distribution function ofdirect continuous links and a set of values for discreet directlinks, and values for linking parameters will be selected basedon the results of integ
49、rated thermal and lighting simulation,taking into account variations in all other links. This iterativesensitivity analysis approach continues until a set of desiredvalues are computed for all parameters, using as measurescorrelations between generalized performance indices gener-ated by the continuous interaction between the two domainsduring the actual simulation process. This dynamic processaims at providing the building designer with performance-based measures for making important decisions for the faadeduring the early design stage, using as basic criteria the follow-ing:Optim
