Wednesday, November 11, 2009

Net Zero Energy Buildings (BL09)

Use on-site renewable energy such as PV or wind.

1 kW of PV produces 1700 kWh/year in NoCal.

Use polycrystaline PV for highest efficiency. (and keep them cool)
Other types of PV.:
Thin film
BIPV, such as shingles

Lay PV panels flat to maximize surface area and production. (tilted, the panels need to be moved apart to keep from shading each other)

2 story buildings allow for a good ratio of electricity production for a given floor area.

Design circuits to shut small PV strings down when they become shaded.

Use power purchase agreements to allow third parties to take tax incentives.

Clean renewable energy bonds. (follow up)

Electrochromic glass to reduce heat gain? Sounds interesting, but it's expensive and requires MORE electricity.

Daylighting - 40 foot building width has been found to be optimal.

Control plug loads - see 2006 ACEEE report

Americans spend 85% of their time indoors.

Don't share thermostats.

Decouple heating and ventilation.

Nationwide, 15% to 20% of all energy goes to power our buildings HVAC systems.

Active chilled beams. Deliver the right amount of air ALL the time.

Radiant cooling reduces energy used to move heat by a factor of 7.

SF Bay water is being used as a heating / cooling element for the new Exploratorium.

Target 50% reduction in computer / server plug loads. Look at server virtualization to eliminate multiple servers.

How do we measure savings?
It's not as easy as product manufacturers will tell you.

Circuit by circuit measurement system to see load shapes.

Commissioning - verify that systems are performing as designed.

Compare modelled energy use to actual energy use.

What about colder climates? (no good answer)

Energy policy in CA makes for less of a difference between the ZEB design and the base case.

Look for automated diagnostics in the future.

Peter Rumsey, PE, FASHRAE
David Kaneda, PE, AIA, LEED AP
Scott Shell, AIA, LEED AP
David Lehrer, LEED AP

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