Energy savings for Watkins School

A project by Mike

This is a great example of an Energy Conservation Measure (ECM) in this case the economic benefit of a shade wall.

Perkins Eastman has been a close colleague over the past 5 years. The sustainable direction I motivated DC government to follow has gone allowed architects to stretch their skills and design amazing projects like this one.

As the sustainability lead on this project, I pushed for the shade wall. Which initially was going to be engineered out of the project because of the cost. I requested an energy model be run with the shade wall. When compared to the building without the shade wall we found savings. The Heating Cooling system could be right sized and built 28 tons smaller.

This allowed us to save $4,800 a year in utility costs which gave use a 10-year Return on the investment.

Small changes have big impacts. The energy analysis is below.

The initial cost of Shades: 10,750 SF x $25/SF = $268,750

Savings in HVAC First Cost: 28 tons x $8,000/ton = – $224,000

Total actual cost of ECM = $46,350

The Savings in HVAC Operating Cost annually is

28 tons x 1,500 hrs./year x 0.75 kw/ton x $0.15/kwh = $4, 725

With a Simple Pay Back (SPB) of 10 years, cost/savings ($46,350/$4,725= 10).

Operational savings over building life (50yrs) = $236,250

There also ends up being a Life Cycle Emission Reduction or 932 metric tons C02; 3 metric tons S02; and 1.4 metric tons NOx.