1) Students at UNC Greensboro designed and constructed a low-cost linear Fresnel reflector that maximizes solar energy collection for a single solar vacuum tube. 2) An Arduino microcontroller calculates the sun's position throughout the day and controls a stepper motor to rotate the reflector's mirrors accordingly. 3) The reflector uses a lightweight aluminum frame, 3D printed components, and a simple design to be affordable and appealing for residential solar applications.

1. An Arduino controlled linear Fresnel reflector
Taylor Grubbs and Liam M. Duffy, Department of Chemistry & Biochemistry, the University of North Carolina at Greensboro, Greensboro NC
An Arduino controlled Linear Fresnel Reflector
Submission is for research1
Student author - Taylor Grubbs, Undergraduate Physics
Faculty Advisor - Dr. Liam Duffy
Department of Chemistry and Biochemistry, UNC Greensboro
Student contact info: (919) 498-4462 tegrubbs@uncg.edu
Advisor contact info: (336) 263-8015 liam_duffy@uncg.edu
We have designed and constructed a simple, low-cost method of maximizing the amount
of solar energy captured by a single solar vacuum tube using a linear Fresnel reflector.
This is accomplished through several features. The first of these is giving the concentrator
the ability to “follow” the sun, that is, the mirrors and the frame of the reflector
automatically rotate as the sun moves throughout the day. The movement of these is
controlled by modification of an Arduino solar tracking program created by the institute of
Earth science research and education2
. Instead of using light-sensing hardware, the
Arduino microcontroller continuously calculates the sun’s position with the aid of a battery
controlled Real Time Clock (RTC). This program was modified to control the motion of a
small stepper motor that rotates a timing belt to which each mirror is linked. The second
feature is that the frame of the collector is made entirely of prefabricated T-slotted
aluminum, making the reflector both lightweight and durable. Each mirror along with the
vacuum tube itself are held by 3-d printed plastic components which were designed and
printed in our lab. Assembly of this model is simple and relatively short, making it
appealing to the average solar hobbyist or experimentalist. We hope to use this device to
power a Duplex Stirling- engine-heat pump that would reduce heating costs for a typical
home. Further work on the device can also be done to create a much more consumer
friendly and marketable product. The device could also be modified for solar power
generation and/or solar desalination. In summary, using modern microcontrollers, pre-
made aluminum framing, and simple 3-d printed parts we have developed a new device
that provides consumer friendly access to solar energy.
1. This project was funded by a Triad Interuniversity Project (TIP) grant as part of Four
University Solar Consortium between Wake Forest University, Winston-Salem State
University, NC A&T State University, and UNC Greensboro.
2.Brooks, D. Arduino Uno and Solar Position Calculations. Institute for Earth Science
Research and Education. Pennsylvania. February 2015.
An Arduino controlled Linear Fresnel Reflector
Submission is for research1
Student author - Taylor Grubbs, Undergraduate Physics
Faculty Advisor - Dr. Liam Duffy
Department of Chemistry and Biochemistry, UNC Greensboro
Student contact info: (919) 498-4462 tegrubbs@uncg.edu
Advisor contact info: (336) 263-8015 liam_duffy@uncg.edu
We have designed and constructed a simple, low-cost method of maximizing the amount
of solar energy captured by a single solar vacuum tube using a linear Fresnel reflector.
This is accomplished through several features. The first of these is giving the concentrator
the ability to “follow” the sun, that is, the mirrors and the frame of the reflector
automatically rotate as the sun moves throughout the day. The movement of these is
controlled by modification of an Arduino solar tracking program created by the institute of
Earth science research and education2
. Instead of using light-sensing hardware, the
Arduino microcontroller continuously calculates the sun’s position with the aid of a battery
controlled Real Time Clock (RTC). This program was modified to control the motion of a
small stepper motor that rotates a timing belt to which each mirror is linked. The second
feature is that the frame of the collector is made entirely of prefabricated T-slotted
aluminum, making the reflector both lightweight and durable. Each mirror along with the
vacuum tube itself are held by 3-d printed plastic components which were designed and
printed in our lab. Assembly of this model is simple and relatively short, making it
appealing to the average solar hobbyist or experimentalist. We hope to use this device to
power a Duplex Stirling- engine-heat pump that would reduce heating costs for a typical
home. Further work on the device can also be done to create a much more consumer
friendly and marketable product. The device could also be modified for solar power
generation and/or solar desalination. In summary, using modern microcontrollers, pre-
made aluminum framing, and simple 3-d printed parts we have developed a new device
that provides consumer friendly access to solar energy.
1. This project was funded by a Triad Interuniversity Project (TIP) grant as part of Four
University Solar Consortium between Wake Forest University, Winston-Salem State
University, NC A&T State University, and UNC Greensboro.
2.Brooks, D. Arduino Uno and Solar Position Calculations. Institute for Earth Science
Research and Education. Pennsylvania. February 2015.
Abstract
Solar Vacuum Tubes
Appalachian Energy Summit, Appalachian state University, July 13-15, 2015 Boone, NC
Control Applications/Conclusion
An Arduino Uno calculates the position of the sun and updates
mirror orientation via a small stepper motor, providing maximum
collection throughout the day. This single motor controls a
pulley that rotates each of the 29 mirrors of this model.
A sample of the calculation code from the Institute for
Earth Science research and education is shown below.
An Arduino Uno calculates the position of the sun and updates
mirror orientation via a small stepper motor, providing maximum
collection throughout the day. This single motor controls a
pulley that rotates each of the 29 mirrors of this model.
A sample of the calculation code from the Institute for
Earth Science research and education is shown below.
Linear Fresnel reflector
Solar vacuum tubes offer a cheap method of transporting energy reflected by the LFR.
Heat is captured by the vacuum tube and transported via a vapor to an external reservoir.
The combined reflection of the mirrors will be delivering about 3.2 kilowatts to the solar tube.
Solar vacuum tubes offer a cheap method of transporting energy reflected by the LFR.
Heat is captured by the vacuum tube and transported via a vapor to an external reservoir.
The combined reflection of the mirrors will be delivering about 3.2 kilowatts to the solar tube.
This Linear Fresnel reflector was designed with 5 purposes in mind:
1)Operation of a Stirling engine
2)Hot water generation
3)Heated oil generation for thermal heat storage and home heating
4)Evaporative water desalination
5)Possible incorporation of photovoltaic cells
It is these applications that this LFR model will be adapted to with
further research.
This Linear Fresnel reflector was designed with 5 purposes in mind:
1)Operation of a Stirling engine
2)Hot water generation
3)Heated oil generation for thermal heat storage and home heating
4)Evaporative water desalination
5)Possible incorporation of photovoltaic cells
It is these applications that this LFR model will be adapted to with
further research.
Our linear Fresnel reflector directs all light incident upon a surface
to a single line. This model is designed for use with residential housing
as modeled below.
Our linear Fresnel reflector directs all light incident upon a surface
to a single line. This model is designed for use with residential housing
as modeled below.
Solar Vacuum tubes
The collection surface area of this model is about
4.3 meters.
The collection surface area of this model is about
4.3 meters.
The user must enter only their latitude and
longitude. The time information is controlled by a
Chronodot® Real Time Clock. This clock is battery
powered so even in the event of a power outage
the LFR will not lose its place.
The user must enter only their latitude and
longitude. The time information is controlled by a
Chronodot® Real Time Clock. This clock is battery
powered so even in the event of a power outage
the LFR will not lose its place.
Note the use of 3-D printed partsNote the use of 3-D printed partsAll of the models shown here depict the LFR with its tilt fixed at one angle
our most final design enables the user to adjust this tilt to compensate in
the change is solar elevation.
All of the models shown here depict the LFR with its tilt fixed at one angle
our most final design enables the user to adjust this tilt to compensate in
the change is solar elevation.