Live from HomeLab, it’s time to evaluate our experimental environment! While the Wood Chimney Experiment racks up data, the team is trying to better understand the thermodynamics of their Lab. Of course by “Lab” the Thermal Mass and Bouyancy Ventilation Research Project Team means their carport. Let’s get into it!
Quickly after building the Wood Chimney the team noticed sunlight hitting it’s lower half in the early morning. Although a small amount of morning sunlight will not stop the Optimal Tuning Strategy from cooling and ventilating the Wood Chimney chamber, it creates unequal conditions between experiments. One of the objectives of this research project is to understand if southern yellow pine is comparable to concrete as an internal thermal mass material. Due to concrete’s thermal properties, it is consistently used as a thermal mass material. If the team can prove that wood can also be a consistent thermal mass material when sized correctly the rural south can utilize their natural resources to provide not only structure in builds, but temperature and ventilation control. Therefore, these experiments need to have equal conditions.
The first step in creating a more equal environment was building a shade structure for the low, eastern light. Made of dimensional lumber and an extra blue tarp, the shade screen blocks any direct sunlight from hitting the chimney while allowing air to enter the bottom of the chimney. This will equalize the amount of heat from direct sunlight, also known as radiant heat, the Concrete and Wood Chimney’s experience. However, the radiant heat on the eastern side of the Lab, shown on the left above, experiences may lead to higher ambient air temperature around the Wood Chimney.
Concrete Chimney 
Wood Chimney 
To understand if this is having a significant effect on the Wood Chimney in comparison to the Concrete Chimney the team got out the FLIR thermal imaging camera. Thermal imaging is simply the process of converting infrared radiation into visible images that depict the spatial distribution of temperature differences in a scene viewed by a thermal camera. This will help us understand the distribution of heat in the lab. From the thermal imaging photos, we can see the difference in temperature in the Lab. The eastern side, on the upper left, because of the radiant heat from the sunlight stays consistently warmer. The western side, on the lower right, is cooler than the rest of the space because it is mostly shaded from any sunlight. Also, due to the size of the Lab, there is clear heat stratification. As heat rises, it gets stuck under the ceiling. While this environment is not detrimental to the experiments, the team is hoping to be able to move the experiments to the Fabrication Pavilion on Morrisette Campus. There, the experiments will have more consistent shade in a much larger space. The larger space will make a more consistent environment as heat will stratify farther away from the top of the Chimneys.
The team has also begun thinking about their next scale of experiment. They want to test the Optimal Tuning Strategy at human scale. This means the space needs to be large enough for someone to experience the cooling effects as well as see what an internal thermal mass looks like in a space. Scaling up, besides being experiential, will also seek to prove that the Optimal Tuning Strategy is truly proportional and applicable for public buildings. The team has to consider what proportions of space will make the Human Scale Experiment data comparable to the Test Chimney data. This is not so straight forward as they need to make sure the experiments do not become too tall or tight as to impede quick, safe construction as the Human Scale Experiment will be a temporary structure for testing. The Thermal Mass and Buoyancy Ventilation Team is using the Optimal Tuning Application to design the Human Scale Experiment at this schematic phase. The application was recently published by Wolfram Demonstrations Project! The team will soon do a post on understanding and using the app.
Last, but not least, here is a thermal image of HomeLab mascot Dijon. No conclusions were made about Dijon based on his environment. Keep Tuning in as the TMVRP team works from HomeLab!
