How the System Works

Data Acquisition


Students, faculty and collaborators from the National Renewable Energy Lab installed over 150 environmental sensors in the AJLC building and landscape. Sensors that measure everything from energy consumption to CO2 levels to dissolved oxygen levels in wastewater were installed and wired to datalogging computers. We are able to measure everything from energy consumption to CO2 levels to dissolved oxygen levels in wastewater via installed sensors that are wired to datalogging computers.


The sensors utilized in the AJLC monitoring system translate environmental conditions and building performance variables into an electrical signal. There is a variety of different sensors deployed in the AJLC building and landscape. Below are some examples:

  • Temperature: Temperature sensors utilized include thermistors and thermocouples. Thermistors are thermally sensitive resistors that exhibit a large, predictable and precise change in electrical resistance when subjected to a corresponding change in temperature. Thermocouples are sensors for measuring temperature. They consists of two dissimilar metals, joined together at one end. When the junction of the two metals is heated or cooled a voltage is produced that can be correlated with temperature.

  • Electricity: Flows of energy in the AJLC (both production and consumption) are measured with pulse output WattNodes®. A pulse (electrical switch closure) is proportional to a fraction of a kilowatt-hour. Monitored electrical circuits include photovoltaic system output, total building consumption, lighting loads, heating, ventilating and air conditioning loads, and additional sub-systems within these categories.

  • Water: Similar to electrical sensors, water flow meters in the AJLC produce a pulse (switch closure) for a fixed volume of water as it flows by (usually one gallon). Most water meters in the building also have totalizers that can be read manually.

Data Processing and Display

Raw readings from the various sensors are collected and processed by data loggers before being sent to Lucid’s BuildingOS technology for analysis and display on the web.

The environmental dashboard digital screen hangs on a wall in the atrium of the AJLC.
The Environmental Dashboard and welcome sign in the AJLC Atrium