14. GLOSSARY OF TERMS AND INDEX

174 14. GLOSSARY OF TERMS AND INDEX

A

Air-mass number A measure used to define the spectral distribution of sunlight for the illumination equipment used to test modules. It repre-sents the path length of sunlight through the atmosphere and is expressed in comparison with unit path length where the sun is directly overhead (only possible for latitudes between the Tropic of Cancer and the Tropic of Capricorn).

Air-Mass 1.5 (AM 1.5) The air-mass number where the path of sunlight through the atmosphere is 50% longer than when the sun is directly over-head. The sun’s direction is 48° from the overhead position, as relevant for latitudes outside of the Tropics.

Alternating current (AC) Electric current in which the direction of flow is reversed continuously. The conventional grid supply is AC at 60�Hz in Europe and 50�Hz in North America.

Amorphous The microscopic physical state of a solid in which the atoms are not arranged in the orderly pattern of the crystalline form.

Awnings Covering to screen persons or parts of buildings from the sun or rain.

B

Balance of system (BOS) The parts of a PV system other than the PV array itself, for example support structure, wiring, isolators and invertors.

Building envelope The outside of a building that contains the interior space, including the roof, the skin or waterproof covering of the structure.

Bypass diode A bypass diode is connected in parallel across a part of the solar cells of a PV module. It protects these solar cells from thermal destruction in case of total or partial shading of indi-vidual solar cells whilst other cells are exposed to full light. It is connected in reverse to the polarity of the module so that it only conducts when the module is shaded.

C

Cladding panel A generic term for an element which provides a “skin” to the building. It may attach directly to the building superstructure or may be supported off a secondary frame of mullions and transoms.

Conversion efficiency The ratio of the electrical energy produced by a PV cell (or module) to the energy from sunlight incident on the cell (or module). This is usually quoted under standard test condi-tions (STC).

Crystalline The microscopic physical state of a solid where the atoms are arranged in an ordered pattern.

Curtain wall A system of lightweight wall construction usually comprising transparent and opaque panels supported on an aluminium frame which carry no vertical loads other than those due to its self-weight and any equipment attached to it and no hori-zontal loads other than those due to wind, maintenance and occupancy.

D

Dead load Load due to the weight of all walls, permanent partitions, roofs, floors and all other permanent construction.

Diffuse radiation Solar radiation scattered by the atmosphere, particularly clouds.

Direct current (DC) Electric current which flows in one direction from the positive terminal of an illuminated PV module through electric loads to the negative terminal.

Direct radiation Solar radiation transmitted directly through the atmosphere.

Diode An electronic component that conducts electricity in one direction only.

E

Electron Negatively charged atomic particle. An electric current is the movement of electrons through a material, such as a metal or semiconductor.

EVA A common encapsulation medium for cells in PV modules. It is cross-linkable ethylene vinyl acetate.

G

Gasket A preformed elastic seal used between joints of different com-ponents. Often used to accommodate tolerance or movement whilst also providing a barrier against wind and rain.

Global irradiance The total irradiance (sunlight intensity) falling on a surface, this being the sum of the direct and diffuse irradiance.

Grid (on a PV cell) The patterned metal contact on the top of the PV cell.

I

Inverter A PV inverter is a power converter which transforms DC volt-age and current from PV modules into single or multiphase AC voltage and current. A grid-connected inverter is designed to convert energy only when the mains grid is available.

Irradiance The instantaneous intensity of solar radiation on a surface (W/m2).

Irradiation The cumulative amount of solar energy received on a surface (kWh/m2).

Insolation Incoming solar radiation measured at given location and a given tilt angle.

L

Live load Variable load produced by the intended occupancy or use (people, furniture, electrical appliances). Wind load is not included in the live load.

17514. GLOSSARY OF TERMS AND INDEX

Load (electric) Any device or appliance (or set of devices or appliances) which uses electrical power. This contrasts with “live load” which relates to forces exerted on structural members.

Low-emissivity glass Glass with a low-emissivity coating on one surface. This allows short-wavelength energy from the sun to pass through but reflects long-wavelength energy back in.

Low-iron glass “White” glass providing high transparency.

M

Maximum power-point tracker (MPPT) Part of a PV inverter which functions as an optimal electrical load for PV modules.

Monocrystalline silicon Silicon for a PV cell that has a single and continuous crystal lattice structure with almost no defects or impurities. “Single” is used interchangeably with the prefix “mono”.

Multi-junction cells Two or more different cells with more than one p-n junction. Such an arrangement allows a greater portion of the sun’s spectrum to be converted to electricity.

N

Nominal array power The power rating of a PV array in WP, as measured under standard test conditions (STC).

P

p-n junction A zone in a piece of semiconductor material formed by differ-ent doping types. This is the usual configuration for a PV cell.

Parallel connection A method of interconnecting two or more electricity producing or power-using devices, such that the voltage produced is not increased. However the current is additive. This is opposite to series connection.

Photovoltaic (PV) cell A semiconductor device that converts light to electricity using the photovoltaic effect.

Polycrystalline silicon Silicon that has solidified at such a rate that many small crys-tals (crystallites) are formed. The atoms within a single crys-tallite are symmetrically arranged, whereas the crystallites are jumbled together. “Multi” is used interchangeably with the prefix “poly”.

Pressure-equalised The technique of equalising pressure across different cavities in the build-up of façade to avoid rainwater being driven by kinetic energy through the façade.

PV module A collection of interconnected PV cells encapsulated between protective materials (glass, polymers etc), sometimes mounted in an aluminium frame.

R

Rainscreen A relatively cheap, open-jointed cladding system that is erected on rails on a waterproofed blockwork wall, or similar.

S

Series connection A method of interconnecting devices that generate or use electricity so that the voltage is additive. The same current passes through each part of the circuit. This is the opposite of parallel connection.

Solar-selective glass Glass with a solar-selective coating on one surface. This allows the visible spectrum of the radiation to pass through the glass and to reflect part of the long wavelength outward.

Spandrel A type of cladding panel which occurs at floor level to hide the building superstructure, raised floor and false ceiling. It pro-vides insulation and a smoke stop zone.

Standard test conditions (STC) Standard test conditions are defined as an irradiance of 1000�W/m2 at normal incidence, a spectral distribution of that irradiance equivalent to AM1.5 and a cell temperature of 25°C.

Stand-alone (PV system) An autonomous or hybrid photovoltaic system not connected to a grid. Most stand-alone systems require batteries or some other form of electricity storage.

Stick system A type of curtain walling where individual mullions and tran-soms are assembled on site to form a secondary frame to which cladding panels are attached.

String A number of PV modules connected together electrically in series.

Structural glazing A system of retaining glass or other materials to the alumin-ium members of a curtain wall using silicon sealant. These systems use no mechanical fasteners, and as a result have no profiles casting shadows on the glazing surface.

System yield Useful energy supplied to the load by the PV system, which is expressed as a function of the nominal array power (kWh per kWP) and over one year.

T

Tedlar Dupont trade name for a film of polyvinyl fluoride (PVF). A commonly used laminate for the back surface of PV modules.

U

Unitised system A type of curtain walling where mullions, transoms and clad-ding panels are factory-assembled into units, often 1.5�m wide by a storey height, before delivery to site.

W

Watt (W) Unit of power. Check context because it can refer to light energy with irradiance or electrical energy.

Watt-hour (Wh) Unity of energy; one Wh is consumed when one watt of power is used for a period of one hour.

Watt peak (WP) Power output of a PV module under standard test conditions.

176 14. GLOSSARY OF TERMS AND INDEX

IndexA―AC 22, 37accidental damage 59AC distributor sub-panel 81Acoustic performance 57AC output 15acrylic Plexiglas 29air barrier 55, 70air gap 46air-handling unit (AHU) 119air leakage 57air mass 30air permeability 55air space 57air space cavity 70airtightness 44, 55, 57Alan Gilbert Building 106aluminium frame 25, 102amorphous silicon 20, 25, 40annual area yield 170anti-reflection (AR) 18anti-reflection coating 22apartment block 150area requirement 21area yield 171array wiring 60atria 45, 51, 130

B―back contact 19back ventilated type 85balance-of-system (BOS) 15, 42battery storage 10bespoke PV modules 26, 49, 50, 52, 73bifacial PV cell 21biomass 158bird dropping 60blast requirements 102boiler plate specification 30bolt-fixed 84bolt-on PV modules 104, 123bomb blast 44, 54, 59boron 16broken glass 59buffer zone 51, 118building integrated PV 10, 11, 44building management system 62building movements 54busbars 19bypass diodes 39, 60

C―cable outlets 25cables 60cadmium telluride (CdTe) 20, 25California Academy of Sciences 138canopy 45, 51, 130, 140carbon pricing 9cavity 55, 117, 118, 121cell arrangement 27

charge carrier 39chimney effect 118cladding materials 11cleaning 59, 62, 64, 74, 133CO2 81Code for Sustainable Homes 156cold façade 47component failure 59condensation 51, 121, 131connecting leads 25connection concepts 37conservation area 12, 163construction 58construction design and management (CDM) 58copper indium diselenide (CIS) 20, 25, 146corrosion 60cradle running 74crystal ingot 18crystalline silicon 16, 40curtain wall 46, 48, 163custom module 26Czochralski method 18

D―damp climates 46daylight 44, 48DC 15, 22, 37DC insolators 81dead cells 26dead load forces 48de-lamination 60design integration 9design life 53diffuse irradiance 33dirt 51, 131display unit 81double-glazed units 23, 53double-skin façade 45, 51, 117, 150, 163double-wall construction 47Doxford International Business Park 32drained and back ventilated 72dry glazing 102dummy PV-modules 26, 38

E―edge-defined film-fed growth (EFG) 18efficiency 16, 28, 40electrically inactive PV modules 79electrical output 41, 42, 60electron 16encapsulation 22, 23energy-efficient building design 9energy meters 154energy strategy 150envelope performance requirements 53EPDM 55ethylene vinyl acetate (EVA) 23, 25exhaust fumes 60external blinds 63extruded aluminium 101extrusion process 52

F―façade systems 9facing leaf 46fan-supported ventilated façade 118feed-in tariff 9, 15fire fighting knock-out glazing 57fire protection 72fire resistance 101fire safety 57flash simulator 30floor to floor separation 79flying leads 60frame 25frameless modules 25frit 28

G―Galleria Naviglio 66gas fill 57gasket 55glare 117glass-glass laminate 19, 27glass thermal stress 58glazing systems 102global insolation chart 34global irradiance 33grade II listed 76green design strategy 66greenhouse gas emissions 152green roofing 66grey-water treatment 152grid-connected 10, 15, 41ground mounted 10guarantee 24g-value 56

H―heat gains 56heat loss 40, 51, 56heat-recovery ventilation 156heat soak test 59heat-strengthened glass 109heat-treated glasses 58heritage buildings 163heterojunction with intrinsic thin-layer 21high performance coatings 131high-performance PV 21high-rise buildings 50HIT PV cell 21hook-on PV modules 123hose tests 55housing 150hybrid glazing 102hybrid HIT 145hybrid ventilation 119

I―IEA 10, 12inclined façade 106indoor environment 56infiltration 44, 55

17714. GLOSSARY OF TERMS AND INDEX

infrared 16, 21insolation 33, 41, 170installed PV capacity 11intensity of radiation 30interlayer 28, 109internal seals 57inverter 37, 60, 81, 168, 170ironmongery 53irradiance 33

J―jointing 54Jubilee Campus 134junction box 25, 60

K―K2 apartments 152

L―laminated glass 59laminated glass modules 84laminated safety glass (LSG) 23latitude 170lay-on systems 11, 51life expectancy 24light emitting diode (LED) 82, 84, 85light-filtering 27load-bearing masonry 46loads 44logging errors 60louvres 46, 62low-energy thermal performance 156low-rise building 49

M―maintenance 58, 59, 60, 74, 80, 133Manchester College of Art & Technology 75mast climber 80material failure 59maximum power point tracker (MPPT) 37measured output 170mechanical ventilation 119metal contacts 16metal facing 101metallisation grid 19micro-wind turbine 158mismatch losses 37mock-up 55module efficiency 21moisture barrier 47monocrystalline silicon 18mortar 46mosaic tesserae 76moveable blinds 62mullions 49mullion-transom stick system 49multi-coloured polycrystalline 28multicrystalline silicon 19multi-storey buildings 104museum 138

N―natural stone 100natural ventilation 117, 154net-zero carbon 156nickel sulphide (NiS) 59night cooling 117nominal operating cell temperature (NOCT) 30, 40non-combustible insulation 57non-optimal orientations 34Northumberland Building 73, 164n-type 16

O―Odersun Solar Circles 146off-grid 10office building 56off-the-shelf solar modules 73orientation 33, 170outdoor-indoor transmission class (OITC) 57overcladding 73, 78overhead cables 39overhead glazing 59overheating 39, 56, 154, 158overshadowing 35, 63

P―passive solar design 152perforations 27, 93, 133performance 41, 53, 168phosphorus 16photoelectric process 16photovoltaic 10planning authority 78planning regulation 163plug-and-socket 60polycarbonate plexi-glass 29polycrystalline cells 109, 110polycrystalline silicon 19polyethylene terephthalate (PET) 23polytetrafluoroethylene (PTFE) 23polyvinyl butyral (PVB) 23polyvinyl fluoride (PVF) 23Pompeu Fabra Bibiliothek 124post-and-rail construction 49powder coating 52power output 81prefabricated façades 50pressure caps 102pressure equalisation 55, 72, 80, 101, 131pressure plate 102, 109procurement 52proprietary tiles 150p-type 16PV 10PV array 15PV cell 15PV inverter 15, 22PV module 22PV modules 15PV panel 15, 22

R―rain 60rain penetration 70rainscreen 45, 46, 70, 72, 150, 163rainwater 131refurbishment 70, 163remediation 70renewable energy 10replacement 59, 74, 104, 133residential buildings 56, 150resin 23, 29, 109resistance losses 19roof-mounted 10, 51roof system 9

S―safety 58, 59scaffolding 49sealants 53seismic forces 44, 48, 54self-shadowing 46semiconductor materials 16semi-transparent PV 27, 126series strings 37serviceability limit state 54shading 45, 60, 62, 158, 166, 170shading device 117, 122, 150shadow box 100, 131shadow losses 19shaft box ventilated façade 120silicone 16, 21, 55single crystal 18single-leaf solid wall 47skylight 130, 140smoke seal 57snow loads 54soiling 60solar energy transmission 56solar factor 56solar gains 46, 56solar heat gains 44solar hot water 154solar radiation 56Solar shade control act 36solar spectrum 16solar thermal panels 158solar water heater 40sound insulation 57sound transmission class 57space heating 56specific yield 30, 42, 170spectral distribution 30spider clamp support system 85stack effect 118stand-alone systems 10, 15standard test conditions (STC) 30STC 30, 57stick-curtain wall 131stick-system 45, 48, 122, 150, 163stiffness 54stone facing 101string 37, 81string inverter 38

178 14. GLOSSARY OF TERMS AND INDEX

string ribbon 18structural bracketry 53structural performance 54structural silicone 102, 109sub-array zones 37sunlight reflection 84sun path 35, 170sunscreen 46sun-shade 46, 63sunshade louvre 133sunshading 51, 130sun’s path 33supercell 148super-insulated building fabric 158sustainable architecture 152

T―Tedlar 23, 25Teflon 23temperature 30, 40tempered glass 25test standard 26thermal breakage 58thermal buoyancy 118thermal performance 56thermal stress 58thermal transmittance 56thermoplastic polyurethane (TPU) 24thin film 16, 79thin-film amorphous silicon 110thin-film encapsulation 25thin-film modules 27, 29thin-film technologies 20tilt 33, 170timber frame 150tin oxide 20tolerances 54toughened glass 58traditional build 163translucent 27translucent diffusive appearance 84translucent glazed modules 84transom 49transparency 27, 170transparent conductive oxide (TCO) 20trees 35, 36, 39

U―ultimate limit state 54unitised 45, 150unitised curtain wall 131unitised curtain walling 100unitised panel 100unitised system 50, 122, 163University of Nottingham 134Upton ZED Terrace 156U-value 56

V

vandalism 53, 59vapour barrier 70Vauxhall Transport Interchange 142vegetation 35

ventilated cavity 117ventilation 40, 44ventilation cowls 158ventilation paths 121ventilation strategies 118visually inspect 60voltage drop 60voltages 58

W―walkway system 63warm façades 48water consumption 152water ingress 55waterproofing membrane 70watts peak (WP) 30weathering gaskets 53weather-tightness 44, 55, 131wet glazing 102white glass 22wind cowls 134wind loads 54wiring 37, 63, 170wood pellet 158workmanship 55

X―Xicui Entertainment Complex 82

Z―zero-carbon dwelling 158zoning 38

AcknowledgementsThe first concept for this book was a façade engineering design guide by Pieter Mattelaer in 2003 for internal use at Arup. This was later developed in 2005 in an architect’s guide by Ignacio Fernandez as part of a collaborative research pro-gramme, “Improved Building Integration of PV by using Thin Film Modules in CIS Technology”. We are grateful for funding of that research under the EU’s Sixth Framework Programme, Priority 6.1 “Sustainable Energy Systems”. Also our thanks go to Dieter Geyer and EU colleagues in the research consortium.In bringing these earlier works up to date, we are indebted to contributions from and review by colleagues both at Arup and from other organisations. Particular thanks on technical input go to Edith Mueller, Graham Dodd, Rick Wheal, Chris Jofeh, Deborah Lazarus, Harris Poirazis and Professor David Infield. We are very grateful for critique of the text by Richard Hough, Colin Axon, Professor John Twidell, Ann Marie Aguilar, David Seager, Malcolm Ball, Jacob Dunn and Antony Rix. Also our thanks to Laurent Ngoc in the Arup Berlin office for his commitment to technical accuracy in the German version. We wish to record our appreciation to project directors and others who have ena-bled us to describe the case studies as accurately as possible. Any omissions or inaccuracies are our fault. Thanks go to Keith Rudd, Natalie Drew, Alisdair McGre-gor, John King, Steve Walker, Schaun Landman, Carlos Prada, Nick Adams, Cody Andersen, Korinna Penndorf, David Fletcher, Keith Morrison and Pagani Paola.For coordinating all the photographs, we are indebted to Flora Tonking and staff in the Arup Photo Library, particularly Pauline Shirley and Joanne Johnstone. Deborah Bird and Angela Bennett were very helpful with sourcing images, and we extend our appreciation to the many photographers who have allowed their work to be used. Conversion of our sketches into quality graphics owes to the dedication of Phil Bogan, Sam Wai, Sean Mcdermott and Daniel Blackhall. Additional help has been provided by Rebecca Roberts and Jenny Bonwick, and financial support was pro-vided by the Arup Design and Technical Fund.Finally we are very grateful to Ulrike Ruh, Nadine Rinderer, Alexander Felix and Jan K. Knapp of Birkhäuser for their imagination and dedication to converting our work into this book with such care.

Authors: Simon Roberts, Nicolò GuarientoEditorial collaboration: Alexander Felix, Jan K. KnappPicture editors: Flora Tonking, Jan K. Knapp

Cover: The Xicui Entertainment Complex, Beijing, part way through installation of the PV and LED facade. Photo: Frank P. PalmerCourtesy: Simone Giostra & Partners/Arup

Layout and cover design: Nadine RindererTypesetting: Nadine Rinderer, Amelie Solbrig

The technical recommendations contained in this book reflect the current state of technology. However, they expressly require to be checked explicitly against current valid laws, regulations and stand-ards of the country in question by the specialist planning bodies responsible. Author and publishing house can under no circum-stances be held liable for the design, planning or execution of faulty structures.

Library of Congress Control Number: 2009924919

This book is also available in a German language edition:ISBN 978-3-7643-9949-8

Bibliographic information published by the German National Library The German National Library lists this publication in the Deutsche National bibliografie; detailed bibliographic data are available on the Internet at http://dnb.d-nb.de.

This work is subject to copyright. All rights are reserved, whether the whole or part of the material is concerned, specifically the rights of translation, reprinting, re-use of illustrations, recitation, broadcast-ing, reproduction on microfilms or in other ways, and storage in data bases.For any kind of use, permission of the copyright owner must be obtained.

© 2009 Birkhäuser Verlag AGBasel�·�Boston�·�BerlinP.O. Box 133, CH-4010 Basel, SwitzerlandPart of Springer Science+Business Media

Printed on 100% recycled paper. Printed in Germany

ISBN: 978-3-7643-9948-1

9 8 7 6 5 4 3 2 1 www.birkhauser.ch