LED Solar Simulator

Document Type


Journal/Book Title/Conference

USU Student Showcase

Publication Date


Faculty Mentor

Byard Wood


There is increasing global interest in growing microalgae as a feed stock for biofuels that can be a direct substitute for diesel and gasoline. Microalgae can produce more lipids (oil) per cultivation area than any other plant on land that does not compete with food crops. One of the crucial components of a high lipid yield for microalgae is light exposure. Understanding the effects of light intensity and spectrum on algal growth is a critical point of investigation for USU's BioEnergy Center. While it is known that light in the PAR (photosynthetically active radiation) range is required for growth, the spectral effects on algal species in this range are not well understood. It was the BioEnergy Center's intention to design a LED light source whose photon flux could be varied for specified wavelengths within the PAR range.

To meet this need, an LED array was developed that utilizes 26 different types of programmable LEDs, which are assembled in 32 LED banks for a total of 900 LEDs. This configuration allows the device to produce a large variety of different spectrum conditions spanning from 375-720nm. The LED banks are connected to PWM (pulse-width modulation) units that let the user control the duty cycle of each bank. This allows the light intensity of each bank to be adjusted for specific applications. Testing performed in an integrating sphere has provided the spectral data for the LED array at full intensity as well as other lower intensities. Utilizing an integrating sphere can also provide the possibility to tune the LED array to match the spectrum of another light source within the 375-720nm range, such as the sun.

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