By Beatrice K Otto
AIR
BREATHE EASY
Fresh Air, Perfect Temperature
Maintaining or improving air quality and thermal comfort can have a striking effect on staff health, alertness, well-being and productivity through:
- maximising individual control
- reducing heat gain, by using lighter coloured exterior surfaces to reflect sunlight from the building, shading devices, or increased daylight
- buildings that breathe - using natural ventilation as far as possible
- low-emission furniture, materials, paints and so on
- greenery, both indoors and outdoors for shading and air purification
DEFRA's Nobel House refurbishment uses ammonia chillers - which boast zero climate change effects - to cool internal rooms lacking cross ventilation. A combined heat and power (CHP) generator was installed, providing 20% of the building's electricity needs while using waste heat to warm the building in winter, to provide hot water, and to provide cooling, via absorption chillers, to computer rooms all year. The building is also naturally ventilated.
Maximise Individual Control
Energy use drops and productivity rises when people have more control over temperature and lighting levels. This can be as basic as allowing people to open and close windows, as well as more sophisticated sensors and controls.
West Bend Mutual Insurance Company in Wisconsin found that productivity rose by 16% due to a new sustainable building, of which 4-6% was attributed to allowing individual control of temperature, air flow, lighting and white noise. Energy costs dropped 40%. Complaints about temperature levels dropped from 40 per day (calculated to cost US$25 per call) to two per week.
Reduce Heat Gain
Materials can reduce the need for air conditioning, whether due to their physical form, their chemical composition, or their colour, since lighter colours reflect the sun's heat. Lawrence Berkeley National Laboratory has shown that roofs painted in pale pigments can strongly reduce heat gain and air conditioning needs of buildings.
You like your employees to multitask, so ask the same of materials used in office (re)design. Degussa's Radiance is an interior paint that helps keep interior temperatures steady, reducing energy consumption for cooling and heating by up to 15%. Other wonder-paints include exterior paints that reduce heat gain from the sun, and Millennium Chemical's Ecopaint which helps reduce outside pollution by working with sunlight to neutralise smog.
Buildings that Breathe
Maximise natural ventilation and thermal regulation, such as through rooftop stack-assisted ventilation, or displacement ventilation, which allows air to pick up heat at floor level, taking it out the building via ducts or vents as it rises. Or look into wind towers mimicking ancient cooling systems in the Middle East, such as the Monodraught Windcatcher.
In the spirit of biomimicry, Loughborough, Cambridge and SUNY universities are studying termite mounds. Even in the desert, these mounds are models of self-regulating heat and ventilation. Tunnels and air conduits retain stable temperatures and moisture levels while wind energy drives air through the tunnels from the outside.
Go Green to be Cool and Clean
Greenery, inside and outside, can have a dramatic effect on air quality and cooling.
- Green roofs - Chicago's City Hall has a 20,000 square foot green roof which has reduced air conditioning and heating costs by about US$6,000 per year. It keeps the building cool in summer beneath a moist layer, and in winter provides additional insulation. Green roofs such as the Ford factory in Dearborn also have a role to play in storm water absorption, preventing drainage systems from being overwhelmed.
- Hanging gardens - the Aichi Expo 2005 planted a four-storey high vertical garden, called the Bio-lung, with roses, moss, vines and other plants to absorb CO2, release oxygen and help cool the surroundings, reducing the so-called 'heat island' effect of built up areas.
- Leafy shading - p lanting deciduous trees near buildings can help with temperature regulation. Their summer leaves provide shade from the sun, while in winter the sun's heat can reach the building. Trees also lower the ambient outside temperature.
A tree planted near a city building saves ten times as much carbon dioxide as a tree planted in the forest because it reduces the energy used for air conditioning and helps to cool the city. Trees provide shade and soak up groundwater which then transpires through the leaves and further cool the air. A single properly watered tree can transpire 40 gallons of water a day through its leaves, off-setting the heat from eg 100 100-watt bulbs burning 8 hours a day.
Joseph Romm, Cool Companies
Tax Incentives
The Enhanced Capital Allowance Scheme allows you to claim 100% capital allowance for the first year of an investment in energy efficient technologies or products, including:
- automatic monitoring and targeting
- boilers
- combined heat and power (CHP)
- compact heat exchangers
- heat pumps for space heating
- HVAC zone controls
- warm air and radiant heaters
WHERE CAN I FIND OUT MORE?
http://www.eren.doe.gov/femp
The clear, comprehensive Low Energy Building Design Guidelines can be downloaded from the Federal Energy Management Programme website. One of the best overviews of how to reduce energy consumption, including costs, benefits, tools, case studies and further resources, with a superb overview of ventilation strategies.
http://eetd.lbl.gov/ied/ied.html
Lawrence Berkeley National Laboratories Indoor Environment Department considers all aspects of interior health, comfort and efficiency.
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WHERE CAN I SURF MORE?
GENERAL
http://archrecord.construction.com/features/green/archives/0105dirt-1.asp Here's the dirt on green housekeeping is a short, clear piece which considers the maintenance and monitoring procedures and systems needed to keep the indoor environment healthy.
http://archrecord.construction.com/resources/conteduc/archives/0604edit-1.asp Robo buildings: Pursuing the interactive envelope is an entry to the world of smart building envelopes that incorporate ventilation and daylighting to the benefit of occupants and the environment.
http://epb1.lbl.gov/EPB/home.html The Energy Performance of Buildings Group looks mostly at air movement and resulting distribution of energy, pollution and fresh air.
http://www.arc.cmu.edu/cbpd/iw/index.html The Intelligent Workplace has suggestions for air and temperature controls, sensors and natural ventilation.
http://www.ashrae.org/ The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) is known for setting standards in HVAC energy use.
http://www.advancedbuildings.org/ This is a superb source of briefings on a range of sustainable building topics including heating and cooling, and air quality. A great place to start learning.
http://www.wbdg.org/design/emp_hvac.php Energy Master Planning for HVAC Systems in Existing Buildings is another good starting point, which puts sustainable heating, cooling and ventilation in the framework of The Natural Step.
TOOLS
http://www.eere.energy.gov/buildings/tools_directory/subjects_sub.cfm The mother of all tools, with a directory to hundreds of tools for building performance, with sections dedicated to indoor air quality, ventilation and airflow, and HVAC systems tools.
http://www.wbdg.org/design/naturalventilation.php Provides an overview of several natural ventilation analysis tools such as Airpak, Flovent, Fluent and Star-CD.
VENTILATION
http://www.wbdg.org/design/naturalventilation.php An excellent, jargon-free overview of natural ventilation by Andy Walker of the National Renewable Energy Laboratory.
http://www.greenbuildings.santa-monica.org/envelope/envventilation.html A brief overview of techniques for maximising natural ventilation.
http://archrecord.construction.com/features/green/archives/0509edit-1.asp 'Commercial buildings open their windows' is a wonderfully clear introduction to natural ventilation via windows.
www.ecbcs.org/ The Energy Conservation in Buildings and Community Systems Programme is an International Energy Agency initiative to improve the energy efficiency of buildings, with various research projects including Control Strategies for Hybrid Ventilation in New and Retrofitted Office Buildings.
http://www.sunpipe.co.uk/ The company that produces the Monodraught Windcatcher, a rooftop ventilation system that eliminates air conditioning, and the Sola-Vent which combines light piping and solar powered ventilation.
http://www.scienceinpublic.com/freshinnovators/2004/chrisfield/chrisfield.htm The Silenceair has the appearance of a transparent brick which allows natural ventilation while blocking outside noise by up to 85%.
HEATING & COOLING
http://www.azsolarcenter.com/design/pas-1.html Passive Solar Heating & Cooling Manual can be downloaded free, and is a perfect introduction to the subject with clear diagrams and language.
American Society of Refrigeration and Air-Conditioning Engineers (ASHRAE), ASHRAE Handbook of Fundamentals , Chapter 26 looks at natural and fan-forced ventilation.
INDOOR AIR QUALITY
http://eetd.lbl.gov/ied/viaq/ To tap research on ventilation rates and technologies, indoor volatile organic compounds (VOCs), sick building syndrome and particles and other pollution.
http://www.dc.lbl.gov/IHP/ Access to a bibliography of 900 papers (many with abstracts) for the Indoor Health and Productivity Project.
http://www.buildinggreen.com/menus/subtopics.cfm?TopicID=5 The subscription-based Building Green has a section on Indoor Environmental Quality.
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