SAFETY OF URBAN ROOFTOP WIND SYSTEMS

Bruce LipscombeI Want Energy Pty Ltd

LESSON: 1 WHAT CAN GO WRONG WILL GO WRONG

• Any machine that involves moving parts can fail.

• Managing the damage and issues are the biggest problem.

• A risk analysis of the installation, reviewed by piers is invaluable.

• Design systems for a worst case scenario.

LESSON: 2 GET IT RIGHT THE FIRST TIME.

• Plan, plan then plan some more.• Be prepared to invest in the best

equipment.• Train you staff.• Chances are the supplier has no

idea of all the issues, don’t rely on them, its your neck!

LESSON: 3 DO IT ONCE DO IT RIGHT.

• Don’t be pressured into getting a job done in a time that makes you rush!

• Take time to check and double check.

• Most building top turbines are high profile, be aware of getting it right.

• Who is responsible for what?• Structural Engineer.

• A structural engineer is responsible for the design and evaluation of anything that supports or carries a load. A structural engineer must be registered and have appropriate insurance.

• Building surveyor.• A building surveyor is a professional trained in understanding and

interpreting building law. He or she is authorised to assess building plans with a view to ensuring they are compliant with the Building Regulations. In addition to having recognised qualifications, a building surveyor must be registered and must have appropriate insurance.

• Builder.• Builders or building contractors manage and coordinate the

project, manage the purchase and delivery of materials coordinate the work of tradespeople involved in the project.

SYSTEM DESIGN.

• Who is responsible for what?• Supplier.

• Provides the machine along with associated data, data such as loads etc will normally be passed to the builder then to the surveyor and structural engineer for approval or design.

• Building owner.• Supply of plans (may be held by others)• Applications• Insurances on turbines.

SYSTEM DESIGN.

• Worst case–Maximum winds in the area–Multiply x 4

• Blade impact area for horizontal turbine.– 10 x blade diameter at ground level.– Add .5 x for each 10m in height.– So a 5m diameter turbine at 50m has a

blade impact area of up to 175m!

DESIGN CONSIDERATIONS

• Vertical turbine.– Can blade separation be controlled

(mechanical)– A Darrieus turbine blade when

separated usually falls straight down but will be blown by the wind, but will not “Fly”

– A Savonius blade can “Fly” for some distance.

DESIGN CONSIDERATIONS

• What happens in the event of failure.– How do you stop a turbine?• Cataclysmic braking.

– When something fails, a mechanical action causes the turbine to come to a halt, it usually results in turbine destruction but can save lives.

• Tangle systems.– A web of nylon netting can be deployed from a

pack that is attached to the support pole, it will tangle the blades and cause the turbine to stop.

DESIGN CONSIDERATIONS

• Access to the turbine for maintenance.– You WILL need to get to it one day.–What tools will be needed.– Safety training, height management etc.– Removal of heavy objects, how?

DESIGN CONSIDERATIONS

• Electrical design.–What are you doing with the power?• Net or Gross feed in, back to main meter

panel.• 3 phase is the system capable of supporting

the produced power?

– Turbine feed.• May need to be armoured.• Ensure it is larger than the required size as it

may on occasions (Dump Load) be under near short conditions.

DESIGN CONSIDERATIONS

• Electrical design.– Inverter selection.• Ensure the inverter curve matches the

turbine power curve.

–What happens in event of power failure?• Dump load temperatures.• Adequate ventilation.• Vermin nests.

DESIGN CONSIDERATIONS

• Emergency plan.–When it goes wrong everything will

happen at once.• Power out.• Access difficult.

– Have an emergency kit ready at the site.• Flashlights.• Rope.• Tangle nets.

DESIGN CONSIDERATIONS

• Remember life is more important than a piece of machinery.– Try to bring the situation under control.– If you can’t then who do you call?

DESIGN CONSIDERATIONS

• When the turbines are installed.– Remember to work with the fire

department who will set up a plan for themselves.

– Do you need to shutdown the turbines if the fire alarm goes off? – How?

DESIGN CONSIDERATIONS

• Be prepared to walk away.– The risks associated with doing

something you don’t understand is far greater than the monetary gain.

– Its easier to face your limitations than it is to face a coroner.

WORK WITHIN YOUR LIMITATIONS