Abstract
This is the second paper in a four-part series reporting on the test and evaluation of typical carbon-dioxide sensors used in building HVAC applications. Fifteen models of NDIR HVAC-grade CO2 sensors were tested and evaluated to determine the accuracy, linearity, repeatability, and hysteresis of each sensor. This paper describes the performance of the sensors and provides a comparison with the manufacturers’ specifications. The sensors were tested at 40% relative humidity, 73oF (22.8oC) temperature, 14.70 psia (101.35 kPa) pressure, and at five different CO2 concentrations (400 ppm, 750 ppm, 1100 ppm, 1450 ppm, and 1800 ppm). The test results showed a wide variation in sensor performance among the various manufacturers and in some cases a wide variation among sensors of the same model.
In all, 45 sensors were evaluated: three from each of the 15 models. Among the 15 models tested, eight models have a single-lamp, single-wavelength configuration, four models have a dual-lamp, single-wavelength configuration, and three models have a single-lamp, dual-wavelength configuration.
