Portable Classroom Controls Project

Chuck Collins

RCM Meeting

April 27, 2007

The portable classroom

Time clock

User control

Electric heating

No scheduling capability

Electric heat pumps

No A/C

Exhaust fans

Limited windows

No demand charges

Part of PSE rebate program for schools

• List of eligible equipment• Variable rebate amounts

depending on which pieces of equipment installed

• Application for rebate• Rebate amount is close to

cost of controller

Portable classroom control project process

• Project research (cost/benefits, other data)• Make pitch to organization• Rebate application, work with PSE early• Find a contractor to do the work• Commence with project• Set up temperature set-points, times, etc• Verify avoided costs, consumption• Receive rebate

The Project

• 127 portable classrooms• Upgraded thermostat controller• Connected to District DDC through

network• Control setpoints via DDC system• Can verify temps, setpoints, trends, etc• Ability to remotely shut down all portables• Scheduling, snow day, etc

After-project analysis using PSE’s EIS

March 2005 through February 2007

Weekly analysis shows weekend shutdown

Feb 24, 2007 through April 24, 2007

Daily profile 2005: High peak, runs during night hours

First week of March, 2005

Daily profile 2006: Systems running 24/7

First week of March, 2007

Daily profile shows lower demand, lower night consumption

First week of March, 2007

Avoided electricity calculations

• Mar 2005– Cost - $75.22– kWh – 942.26

• Mar 2006– Cost - $182.72– kWh – 2,391.50

• Mar 2007– Cost - $62.97– kWh – 766.45

942.26 + 2391.50 2

= 1,666.9 – 766.45 =

900 kWh per yearor 54%

Avoided cost calculations

• Mar 2005– Cost - $75.22– kWh – 942.26

• Mar 2006– Cost - $182.72– kWh – 2,391.50

• Mar 2007– Cost - $62.97– kWh – 766.45

$75.22 + $182.72 2

= $128.97 - $62.97 =

$66.00 per yearor 51%!

Avoided cost survey• 18 portables at various sites (14% of total)• Used PSE’s Energy Interval Service for data• Total electricity cost March 2006: $2,468.39 • Total electricity cost March 2007: $1,854.49• Avoided monthly cost for sample: $613.90• x 10 months: $6,139.00 annual avoided cost• / 18 portables = $341.05 per portable, per year• x 127 portables = $43,314.05 (estimated annual

avoided cost, based on survey)

Total cost/benefit

• Estimated annual savings: $43,314

• Total project cost: $110,642

• Simple payback (no rebate): 2.6 years

• PSE rebate: $29,750

• Actual project cost: $110,642 - $29,750 =$80,892

• Simple payback (with rebate): 1.9 years

• Thank you!!

• Questions??