Energy Efficient Office

In most organisations a cut in total energy bills of 20-30% is achievable over the first 2 to 3 years of an energy management strategy. 94% of Australians believe that helping the environment by conserving energy and reducing greenhouse gases is an important issue, so becoming Energy Smart could also improve you corporate image. The Sustainable Energy Authority of Victoria has provided the following information on how you can save costs and energy.

Design
Decisions made in the design stage are the most important when it comes to energy efficiency. With the right choices thousands of dollars can be saved on energy bills over the lifetime of a building.

Siting a building within its micro-climate is an important. Factors such as wind, shade and light will vary greatly from site to site. Determining the correct solar orientation, size and types of windows and building envelope will cost you nothing at the design stage, but will have a huge impact on energy costs.

Give consideration to how people are going to get to the building. The energy used in the transportation of workers roughly equals the energy used by them at work. Encourage walking, public transport and bikes.

Effective Use of Daylight
Artificial lighting is often both the greatest energy consumer and energy cost in a building.

By increasing the amount of floor area within four meters of the building edge, the possibility of using daylight is increased, particularly for the south-facing façade, since heat gain will be much less.

North facing facades can also work since they can by shaded, but generally east and west facades should be minimised.

Daylight on lower floors can be maximised by setting back the building facades from adjoining structures by half the height of those structures. This will reduce overshadowing.

Orientation and Shape

The following tips are useful to keep in mind at the design stage:

• Minimise east and west facades.
• Maximise south and north facades.
• Minimise surface area while still maintaining good daylight.
• Maximise floor area that can receive good daylight.
• Set buildings back from their neighbours by a distance of half their height.
• Overheating is best dealt with by stretching out the building in an east-west direction.

Building Envelope
A well-design building envelope can reduce energy costs by up to 50%. It is important to stop heat entering the space in summer and overloading it, as well as escaping the space in winter.

THE MAIN FACTOR AFFECTING THE INTEGRITY OF A BUILDING ENVELOPE IS WINDOW DESIGN.

In summer, a typical unshaded west window can let in 25 times more heat than a wall, and in winter it can let out six times more heat than a wall. To combat this maximise the north and south glass, and minimise the east and west glass. A good rule of thumb is for window areas to be about 40% of the wall they occupy on the north and south sides. Keep east windows as low and as small as possible.

Window design should stop heat from getting inside during summer. Strategies include:

• External shading by trees, awnings or sails.
• Reflective glasss.
• Glasses such as Evergreen™ or SmartGlass™ that have special surfaces to improve their thermal performance while retaining their ability to let in daylight.
• Double glazing.

Natural Ventilation
Typical natural ventilation strategies use the idea that warm air will rise up through a space. This may be applied either in an entire building or in a series of vertical thermal chimneys that are attached to the side of a building, or placed in the middle of a building.

Natural ventilation can be used during the day to provide background fresh air ventilation required in schools, hospitals and officies. It can also be used during the night to cool the whole building mass with air that will come in via low secure vents and exit through large roof openings. In carparks it can also help minimise the use of mechanical ventilation.

Thermal Mass
Materials with a high thermal mass, like bricks and concrete, have the ability to soak up excessive heat and even out temperature peaks. Thermal mass can be utilised is several ways to reduce running costs. A heavyweight builiding will be able to maintain cooler temperatures on a hot afternoon and thus reduce the likelihood of paying peak demand electrical charges during this time.

Thermal mass can also be used to pre-cool the building if night purging is used. In such a case, cool night air is introduced into the building to cool the thermal mass. At the start of the next day, incoming heat is absorbed by the cooled building structure, rather than increasing the office space structure.

Lifts and Stairs
Lifts typically represent 2% of the energy costs in a building. Placing stairs in prominent positions will encourage people to use them.

Lighting Design
Lighting should be designed using a zoning approach in order to minimise wastage. Set up zones so that lights in areas close to windows can be switched of when there is enough light and so that areas used infrequently are only lit when necessary.

Dimmable light switches allow light levels to be set in line with the amount of natural light.

Ensure that light switches are clearly labelled so that occupants know which lights they are turning on. Utilise energy efficient technology in high use areas. The most efficient fluorescent lamps are the T5 type.

Maintenance
To maximise energy efficiency, normal maintainence practise needs to be extended to ensure key energy consuming plant components and systems such as chillers, boilers and the like are kept at optimal condition and performance.

Office Equipment
Office equipment consumes the majority of you power bill, so switch of equipment when it is not required.

Computers:

• Turn of monitors whenever possible, even if it is not practical to switch of the computer. Monitors usually use more energy than the computer itself! Screen savers do not save energy, they simply maximise the screens useful life. LCD Monitors use less power than conventional screens, as do Monochrome screens.
• Most computers come with energy saving features that can be activated to put machines to "sleep" when not being used, in this mode computers will use a fraction of the power they would normally.
• The energy star rating system has been designed to indicate which office equipment is the most energy efficient. Energy star computers will use no more than 30 watts when in sleep mode, standard computures may use 70 or 80 watts..
• Laptop computers draw about one tenth the power of a conventional desktop computer. You can connect a laptop to a standard monitor while at the office and still save almost half the energy of a standard computer.

Faxes, Printers, Photocopiers

• You can install timers to control printers, photocopiers, lights and other equipment to ensure they are switched off after hours.
• Photocopiers are energy guzzlers, using most of their energy to keep their internal surfaces hot, so even when no copying is taking place power consumption remains quite high. Most copiers have an energy saving feature that can be activated to put machines to sleep, but for real savings machines should be switched of at the wall. Other actions that reduce costs include undertaking copying tasks in batches, and using the photo-reduction and double-sided copying as much as possible.
• You can set up you computer to be your fax machine, saving paper and power. The computer can be configured to be on sleep mode until a fax arrives.
• Energy Star rated fax machines automatically power down when not in use and can reduce energy costs by almost 50%. They can also scan double sided pages, reducing both copying and paper costs.
• Energy Star rated printers cut a printers electricity use by over 65%.
• Well maintained office equipment operates better and costs less to run. Over the life of the equipment the total running costs may be five to ten times the initial purchase price. Carrying out maintenance in a planned way saves costs.
• TCO label /MN

Cooling & Heating Hints
Cooling and heating usually accounts for around 10% of a typical small business’ energy bills, but there are heaps of ways to save.

• In Summer most comfortable and economical setting is 24-25° C. For each degree lower, cooling costs rise by 20%. By setting temperatures up by 2° C a business can save $30 to $60 dollars a year. Make sure thermostats are installed in your main work area on internal walls away from heat sources and draughts.
• In winter, the most comfortable and economic setting for the thermostat is 18-20° C. For each degree higher, heating costs rise by up to 20%. By turning down 2° C a business can save $70-$200 a year. Deciding which areas need heating can save costs. Storerooms, toilets and other infrequently used areas can be ‘zoned’ of, or heated to a lower temperature.
• Install adequate shading and insulation. Insulation is the single most effective item you can add to your office to improve its energy efficiency. A well insulated, energy smart office will keep you up to 10° C cooler in summer and 5° C warmer in winter. For best results, all ceilings, walls and raised walls should be insulated. Shading north, east & west-facing windows from the sun by vertical shading devices such as external blinds or shutters is an effective way of keeping houses cool.
• Keep furniture and other obstacles clear of outlets and return air grille to avoid restricting air-flow.
• Occasionally check your ducting for air leaks. Leakage from joints, elbows, and connections can mean loss of 20-30% of total heat. Seal with duct tape or caulking.
• Turn off heating and cooling when not required, leaving systems on 24 hours a day can more than double your costs. Installing a timer system will ensure your business is only air-conditioned when you need it, many controls can be set to turn systems off for the holidays and long weekends.
• A zoned system enables you to cool only those areas you need.
• Turn off office equipment and lighting when it is not required, to reduce the amount of heat produced inside the building.
• If its cooler outside than in, switch of the cooling system and open doors and windows to let the cooler air in.
• Close doors to rarely used rooms, storerooms, toilets and passageways. Turn off air-conditioning to these areas when possible. Fitting automatic door closers will ensure that doors stay shut. If there are no doors, you can install curtain doors across entrances.