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Prepared by: Michael PasƟ, Anders Laub
IntroducƟon
The Problem:
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The lights in the Harrisburg, Pa MLK City Government
Building currently do not turn off.
Energy Audit
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Lighting the building 24-7 uses resources the city could use
to take on other important issues.
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Daylight Harvester
The MLK City Government Center building currently uses the 24 hour fluorescent lighting
schedule (Alternative 1)
reduce the EUI (Energy Use Index)
The Daylight Harvesting circuit dims LED light when there is existing daylight. It is not necessary to
light a space with overhead LED lights when daylight is shining through a nearby window. Our daylight harvesting circuit will dim LED lights when there is temporary daylight and will make the
LED’s brighter when there is no outside light entering the area.
by 31.94 kBtu/ft2
Circuit:
Moving to Alternative 4 would
Alternative 4, a typical 12 hour office
1. Light sensor
outputs high
voltage in low light
lighting schedule, and installing LEDs
results in the lowest operating and maintenance costs.
2. Light sensor generates
signal with high duty cycle in low light
3. LED Lights
Box 1: Using a photo resistor, Op-Amp, Box 1 outputs a low voltage in bright light and will output a
high voltage in low light.
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Box2: The output of Box 1 is fed into Box 2. Using a photo resistor and a 555 timer, Box 2 will generate a square wave with a duty cycle of 50% in bright light. That duty cycle will increase in low light.
Conversion to the 12 hour LED alternative would save $7,575 and 349,420 kWh annually.
The Solution:
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Box 3: The output of Box 2 in fed into Box 3. This contains the LED lights that will increase brightness in low light while dimming when exposed to existing daylight previously sensed in Box 1 and 2.
Calculated the expected energy use for alternative solutions.
Prepared a proposal for an energy saving 12-hour lighting
schedule, and conversion to more efficient LED lights.
Designed daylight harvesting system to install with LED
lights.
Housing:
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This change would cost $16,230, pay
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itself off in 2 years, and save $276,406
over its 11.41 year lifespan.
Clients
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Designed to securely contain circuitry, provide an
aesthetic interface with the room
Contains the light sensor, and blocks unwanted
light for a more precise measurement on the desired surface.
Screw-on cover
3d printed using PLA plastic.
3/8” ceiling tile
Wayne Martin, City Engineer
[email protected]
Our Mission:
Acknowledgements
The Harrisburg Energy Audit group measures and reports on energy consumption in Harrisburg, and prepares suggestions for the improvement and growth of City resources. By decreasing the capitol’s utility bill by at least 25%, those resources can be used to take on other
issues and improve quality of life for its citizens. The Energy Audit project also builds ties
with the City of Harrisburg for future collaborative efforts.
Advisors:
Dr. Harold Underwood, Project Manager
Adam Shamenek
Sponsors: