Arch Building Systems II (2000/2001) Energy and Environmental Systems for Green Buildings Lecture 05 - Energy Efficient Technologies

Contents zTechnological Principles zPassive Building Design zBuilding Services Systems zSolar Energy Systems

Technological Principles zTechno + logical ysensible and effective use of technologies zEco-tech ylow-tech: less technical devices, more natural means (require precise analyses) ylight-tech: build much lighter and more flexible (reduce consumption and demand) yhigh-tech: newest, advanced techniques (* see pictures of buildings in the world)

Technological Principles zEnergy requirements ycooling energy (e.g. space conditioning) yheating energy (e.g. hot water) yelectrical energy (e.g. lighting) zEfficiency approach yreduce energy use & demand yoptimise energy supply & systems ytotal energy (e.g. combined heat & power)

Passive Building Design zBasic concept yinternal conditions are modified as a result of the behaviour of building form and fabric, without or with little mechanical assistance zTechniques ynatural ventilation ythermal storage in building fabric ydaylighting and sun control

Passive Building Design zCooling is the key question in HK zPassive cooling methods ycomfort ventilation (daytime) ynight ventilative cooling yradiant cooling (e.g. using roof or radiators) ydirect evaporative cooling (e.g. cooling tower) yindirect evaporative cooling (e.g. roof ponds) ysoil or earth cooling

Promote wind effect by wing walls Venting a thermal mass wall Examples of passive cooling designs Thermal chimney

Planted roofSecond skin façade

Passive Building Design zDaylighting options ysidelighting (e.g. side wall windows) ytoplighting (e.g. roof skylights) ycourtyards and light wells yatrium and greenhouse yoptical systems to collect, transport and distribute daylight (to inner spaces) xe.g. light pipes, holographic system

Lighting controls and daylighting sensor Daylighting sensor

Building Services Systems zHVAC system ymost important energy consumer yenergy saving techniques x‘free’ cooling methods xheat recovery xdistrict cooling/heating xcombined heat & power (CHP) xdesiccant-based cooling

‘Free’ cooling methods in HVAC system (a) Air-side economiser cycle - intake more outdoor air when its enthalpy (energy content) is lower than indoor air (b) ‘Free’ refrigeration - chiller bypass when the system can be cooled by ambient Enthalpy line

Waste heat recovery - heat pump + chiller

Centralised refrigeration plant District cooling system (Do you know what are its advantages?) Individual buildings

Combined heat & power (also for district heating) Electricity supply Heat supply

Desiccant-based cooling system

Building Services Systems zLighting system ycompact fluorescent lamp (CFL) yelectronic ballast zOther building services systems yelectrical services ylifts and escalators ybuilding management system ywater supply system

Solar Energy Systems zCommon technologies yactive solar (e.g. solar hot water) yphotovoltaics (for electricity) zAdvantages yclean and renewable (reduce fossil fuels) ydecentralised and local resources zMore info about ‘renewable energy’ will be discussed in the coming lectures

Solar hot water system

Photovoltaic (PV) panels

Architectural integration of PV modules

Solar energy systems in Hong Kong Solar heating for a swimming pool complex PV system for a weather radar station