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John Roller

John F. Roller is an electrical engineer in the Heat Transfer and Alternative Energy Systems Group of the Energy and Environment Division (EED) of the Engineering Laboratory (EL) at the National Institute of Standards and Technology (NIST). Mr. Roller currently oversees all data acquisition activities at the Net-Zero Energy Residential Test Facility.  As part of this role, he has developed a system to provide near real-time access to data collected at the facility and has created a system to provide flexible zoning capabilities for the heat pump.  Mr. Roller is also involved in photovoltaics research.  He has developed uncertainty budgets for measurement methods used to predict the short circuit current for photovoltaic devices.  Currently, he is conducting research to assess the performance of photovoltaic devices under indoor lighting conditions.  This work has relevance to the emerging focus on the Internet of Things, as one potential method of powering such devices includes the use of photovoltaics.

John joined NIST in 2009 as a co-operative education student.  During that time, Mr. Roller assisted in data acquisition for thermal insulation measurements, water heater testing, and photovoltaic performance.  During that time, he was on a team that authored a paper that received ASHRAE's 2012 Technical Paper Award.  After receiving his Bachelor's Degree, he continued work at NIST as he pursued a Master's Degree in Electrical Engineering.  His thesis research focused on assessing defects in photovoltaic materials, culminating in a thesis entitled "Contactless Spectral-Dependent Measurement of Bulk Lifetime and Surface Recombination Velocity in Silicon Photovoltaic Materials."

Publications

Challenges of Irradiance-mode Spectral Response Measurements

Author(s)
Behrang H. Hamadani, John F. Roller, Brian P. Dougherty, Howard W. Yoon
Irradiance-mode spectral response measurements of solar cells are important because they provide a direct, reliable and accurate route for determination of the
Created August 15, 2019