Methodology for the Evaluation of Natural Ventilation in ... - Cham

40-location card inserted into the data-recording device. Data could be measured anddownloaded to a computer in real time or to a designated file location on the computer. Thechannels, or locations, on the card were configured for recording temperature measurements,using Type K thermocouple wire, and an internal reference temperature. When the channelswere set up to record data with an internal reference temperature, rather than the external orsimulated, the measurements were all relative to one another, rather than relative to a prescribedreference temperature or ambient reference temperature. By using the internal referencetemperature, the data collected using the Keithley® could be directly compared to thetemperature data recorded using the CR10X. The Keithley® data acquisition system was set upto record data every 0.16 seconds. Since there were 40 locations that were monitored at anygiven time, it took 6.4 seconds for each data set to be recorded. The average temperature over 15measurements was used as the temperature for data analysis purposes. The setup files for theKeithley® data recorder are provided in Appendix A.Thermocouples were used to measure temperatures not monitored within the HVAC system.Type K thermocouples were used throughout the test chamber to record temperaturemeasurements both inside and outside the scale model. The thermocouples were then placed onthe interior of the scaled model, often using a highly heat resistant duct tape to ensure that thethermocouple would remain in place even when exposed to high temperatures (>70°C). In eachheated zone, six thermocouples attached to the CR10X were placed at mid-height in each heatedzone of the model, and a thermocouple was placed on each of the three sides of the atrium at thefirst floor level, and on the two sides of the second floor level. All thermocouples were 2mm indiameter, and the junctions were coated with aluminum paint to reduce the effect of radiation onair temperature measurements. These thermocouples remained in place for the duration of theexperiments. The thermocouples attached to the Keithley® system were moved as neededamong different experiment configurations. These thermocouples were primarily used to recordmore detailed temperature stratification measurements for specific areas of the model underinvestigation.Several globe anemometers were placed on the interior of the model in order to measure theinterior air velocity. The globe anemometers provide an air velocity measurement, but not thedirection of airflow. The globe anemometers had silvered tips and were connected to a dataacquisition system located on the same computer as the CR10X thermocouples. The softwarepackage allows for instantaneous readings using the globe anemometers.Several pieces of hand-held equipment were used to gather data that are more detailed on thereduced-scale model and the surrounding conditions. Hot-wire anemometers were used to takeair velocity measurements at inlet and outlet openings. Due to the geometry of the openings, anaverage velocity was taken over the opening area. The hot-wire anemometer, with a probe sizeof 1mm diameter, had precision of 0.1 m/s. An infrared temperature sensor was used to gatherdata on the surface temperatures within the model and surrounding the model to assure thatthermal radiation effects either between surfaces within the model or between the exteriorsurfaces of the model and the test chamber did not distort experimental results.Additionally, flow visualization equipment was used to determine the airflow patterns within themodel qualitatively and to ensure that there were no significant leaks in the model. Draeger104