Thermal Mass & Buoyancy Ventilation Research Project

Citing, Siting, and Siding; All exciting!

Exciting news, the Thermal Mass and Buoyancy Ventilation Research Project Team have published their Chimney Experiment data onto an online data repository! The team has uploaded data to the Craig Research Group Dataverse through Salmaan Craig at McGill University. Great thanks to the team’s collaborators at McGill, without which this would not be possible.

online data repository interface

The team will continually update and upload data as new data is gathered and past data is analyzed. From there, anyone can download and review the raw and analyzed data for both the concrete and pine experiments. This data is a citable source for any publication investigating the passive cooling strategy. There is also an experiment guide available to download which details the design of the experiments. Using this guide others can replicate or improve upon the experimental setup. This process is great practice for the team as they start writing a scientific paper about their experiments for a peer-reviewed journal. Now for some good ole design talk!

The TMBVRP team decided the experiment is best served as a free-standing structure although they loved utilizing the SuperShed as a super roof and a superstructure. The experiment needs a little extra room to breathe and ventilate than the Supershed can provide. The question remains, where do you place a giant occupiable cooling chimney so it sticks out just enough? Not quite a sore thumb, but definitely not a wallflower.

Along with possible sites for the pods, the team is investigating the use of berms. Why berms? The cooling patio will likely be an excavated area so cool air from the chimneys will sink and collect. This space needs some sort of semi-enclosure to help trap the cool air. Therefore the excavated dirt can create berms, trapping the cool air while providing shade and seating. The berms can also divert water so the cool air pool does not become a catfish pond. The team is analyzing sites in proximity to other pods and Supershed while giving each location a fitting suburb names. Right now they are considering two design schemes: Two Trees and East End.

Two Trees would address the “other side of the street” created by the Supershed and the row of original pods. This site is most appealing due to the natural shade provided by the, you guessed it, two trees. Thanks to team collaborator and Auburn professor, David Kennedy, for introducing the team to shading and solar radiation software. This software, through Rhino, will show exactly how much solar blocking the trees provide. While the trees are a bonus, the water is not. Water from all of Morrisette Campus drains right through Two Trees. This is also why the team has steered away from a site at the west end, the lowest point on campus. At this location, the team also thinks the pods compete with the Supershed in a strange manner. For these reasons, the team decided to take a look at the East End. East End could serve as a continuation or cap to the Supershed. However, there is no hiding from the sun in this location. Thankfully it is more beneficial to the experiment that the pods receive equal solar exposure rather than partial but inconsistent exposure. The team will continue to evaluate both sites.

The team is currently exploring high albedo, ventilated cladding systems. Albedo refers to the amount of energy that is reflected by a surface. A high albedo means the surface reflects most of the solar radiation that hits it and absorbs the rest. A shading or reflective cladding system, when coupled with the use of SIPs, will allow for the interior system to work unaffected by exterior solar heat gain. Metal cladding is an easy way to reflect radiation. A light-colored timber rainscreen can also reflect heat and shade the structure behind it. The team is exploring both options.

The Thermal Mass and Buoyancy Ventilation Research Project Team is also getting into the structure needed to support the pods, 8′ above ground. To start the team looked at a local precedent: silos. In Hale county, silos for holding catfish and cattle feed are aplenty. They can support up to 30 tons with a light-weight steel structure. Steel manual in hand, the team has been investigating how they could apply a similar structure to lift the pods. This allows for an open space beneath for the cooling patio. Next, the team will investigate the possible benefits of using a wood structure.

The team will keep pushing their citing, siting, and siding ventures forward while living it up in Hale County. They’ve been utilizing the great outdoors for grilling and being grilled in reviews. Livia sometimes misses out on the fun as she is dedicated to the landscaping at Morrisette. For more research graduate student shenanigans make sure you stay tuned!

Lab to Barn, Science to Design

Live from Rural Studio Red Barn, it’s the Thermal Mass & Buoyancy Ventilation Research Project Team! The team, though they might come to miss the cat interns and the AC, is so excited to be back on campus. For health safety measures, the team has an entire studio room to themselves which also acts as a convenient hiding place from Andrew Freear. The TMVRP Team is being as safe as possible as they sorely missed Newbern and the Rural Studio staff and faculty. This week the team will cover their pod design process while bombarding you with design iteration images. Enjoy!

As the Wood and Concrete Chimneys chug along, quite literally, the TMBVRP team have been designing their test buildings. Like the Mass Timber Breathing Wall team’s nearly completed test buildings, the TMBV test buildings apply their research at a small building scale. After some initial testing, the TMBV test buildings can be used as 3rd-year accommodations. The Studio calls the funky dorm rooms for 3rd-years on Morrisette campus “pods.” In true Rural Studio fashion, the design of these pods is an iterative process, but must always be grounded in what is necessary for the experiment. Now, science experiments are not only driven by the hard data we might get out of them. Many experiments are experience-based, especially when trying to describe a phenomenon to the public. Think about going to a science museum, touching the electrified ball and your hair shooting up from your head. Static electricity makes a lot more sense to you when you experience it rather than if you had read data and looked over graphs explaining it. The design of the Thermal Mass & Buoyancy Ventilation pods revolves around both data and experience production. A main objective of the Thermal Mass & Buoyancy Ventilation Research Project, while being rigorously tested for data currently, is for inhabitants to experience the comfort of the cooling and ventilation effects. Let’s journey through TMBV Pod design as the team tries to focus on both experiment and experience!

When massing the general size of the pods, the team can use the Optimal Tuning Strategy app. From the app the team knows the amount of surface area needed for the thermal mass, the thermal mass thickness, and the size of the ventilation openings based on the information they input which is how much ventilation, temperature change, and height the pods need. General massing schemes are quickly generated from these design parameters. The team is creating massing schemes for two to three pods, one with concrete thermal mass walls and one or two with wood ones. These massing schemes also explore whether to share walls in a multi-unit pod or separate the pods to highlight the material difference within. As long as these massings can fit the app outputs, a 3rd-year, a bed, and the sensors we need for testing that’s all of the design work to be done, right? Nah. While these are sleeping quarters for students, they are also examples to the public of how spaces that utilize thermal mass and buoyancy ventilation can feel.

To create a peak TMBV experience, the team is elevating the pods! This will allow for a gathering space underneath the pods where anyone can sit and enjoy the cool air being naturally pumped out of the spaces above. The TMBVRP team calls it, the “Cooling Patio.” Here, students, faculty, or clients interested in the system can experience the effects of TMBV without lingering too long in a 3rd-years dwelling. It also highlights one eventual goal of the work; naturally cooled public spaces enjoyed in the Black Belt. The Cooling Patio is located underneath the buildings because the TMBV system operates in downdraft during the day. This means during the day the air is pushed out of the lowest opening as opposed to at night when the air is pushed out of the highest opening. Therefore in a typical building, you would not need to elevate the structure above the ground, you simply need a low and a high ventilation opening. The TMBV Pods’ ventilation “top and bottom” openings are so literal for both the quality of the experiment and the Cooling Patio.

Why the pod is elevated may now be clear, but why do some of these drawings have such tall chimneys? The exaggerated Chimneys are an experiential detail like the elevation of the spaces. They are not necessary for the experiment or the TMBV strategy to work. A typical building would not need tall Chimneys to utilize Thermal Mass and Buoyancy Ventilation, just as they would not need to be elevated. The tall chimneys are specific to the Thermal Mass and Buoyancy Ventilation Research Project Pod as they highlight the ventilation created by the passive strategy. This is another detail, like the cooling patio, that will work as an experiential demonstration of the research. Increasing the overall height of the structure, beyond what surface area is needed, highlights the ventilation aspect of the system. The elongated chimneys do not increase the amount of air ventilated through the spaces, it does increase the speed of the air as it exits the spaces. The faster the air exits the interior space into the cooling patio, the cooler the patio space will feel. Think of it as the difference between being hot with a fan and without. Moving air always increases the cooling effect and therefore the cooling experience. This increased airspeed will help with explaining how Thermal Mass and Buoyancy Ventilation works as visitors and users will be able to clearly feel the cool air rushing out. Now, the design is focused on three main outcomes: replicating the experiment so TMBV works effectively at building scale; providing a comfortable and useful space for sleeping and demonstrating; and creating a space below the buildings in which people can gather and experience the strategy working for long periods of time. What comes next is siting and about 1,000 other details.

Siting began by looking at various locations around the Super Shed and the existing pods. The Team began exploring the pods as stand-alone buildings. Next, the team explored how they could utilize the roof and structure of the Super Shed. While investigating stand-alone sites, the team also did some surveying of the Super Shed. Both options have benefits. A stand-alone structure would allow for greater height, not being capped by an existing roof, so a more generous cooling patio space and higher airspeed into that space. The existing roof of the Super Shed, however, would provide constant shade and rain protection making it a very similar environment to the Chimney Experiments in the carport at HomeLab. Both have experiential and experimental benefits that the team is still exploring.

The Thermal Mass and Buoyancy Ventilation Team has a lot of hard work ahead, but nothing makes it better than being back in the Red Barn. Seeing the old and new faces of Newbern, even from a social distance, is exciting and motivating. Thanks for Tuning in!

New Cat, New Data, New Designs

Live from HomeLab it’s the newest member of the Thermal Mass and Buoyancy Ventilation Research Project team, Sonic! More on our scrappy, little intern later, we’ve got fresh Wood Chimney Experiment results.

Longhaired black kitten shining in the sun

TMBV Research Project’s last post discussed equalizing the environment of HomeLab to improve the accuracy of the Concrete and Wood Chimney Experiments. While the screen on the eastern side is blocking direct solar radiation, the team discovered a new heat source. The roof of the carport is significantly hotter, even on the underside, than the team thought. This was discovered while trying to understand the Chimney’s airflow data. To show how trapped heat can affect the experiments we will take a look at the long-awaited Wood Chimney Experiment Data.

The above airflow data was taken from the first week the Wood Chimney was up and running and shows both updraft and downdraft. Automatically, the Optimal Tuning Strategy is validated for wood, as well as concrete, by the existence of both airflow directions within the experiment. Go, Wood Chimney, Go! However, the updraft is nearly twice as strong as the downdraft which did not quite make sense. The team looked back to their thermal imaging photos for an answer as to why there is such a large difference between the updraft and downdraft.

The thermal imaging photos show that the top of the Wood Chimney Experiment is much, much hotter than the side of the chimney. This can cause a build-up of hot air at the top of the chimney which explains why downdraft is so much lower. While in downdraft, the air is brought in from the top and expelled out of the bottom of the chimney. It works the opposite in updraft, bringing air in from the bottom and expelling out of the top of the chimney. If there is much more hot air at the top of the chimney, that causes turbulence, making it harder to bring in air during downdraft and too easy in updraft. So what is causing this heat at the top? The HomeLab ceiling!

The team learned, from the thermal images above, that the ceiling of the carport was nearly 120 degrees Fahrenheit, which clearly was the reason for the heat build-up at the top of the Wood Chimney Experiment. To combat this the team stapled a radiant barrier to the rafter of the carport to insulate and reflect heat away from the tops of the chimney, trapping it at the ceiling. The radiant barrier is made of Reflectix insulation which looks like shiny bubble wrap. In the thermal images, you can see the radiant barrier lowers the temperature above the chimney by nearly 10 degrees.

The radiant barrier works! Both the thermal images and data show that the excess heat at the top of the chimney was increasing the updraft and making the downdraft more turbulent. The top surface of the chimney also dropped 8 degrees. The amount of air per second is now mirrored in updraft and downdraft at about 0.05 l/s.

in the last post, the team left y’all with thoughts on a “Human Scale” experiment, to test the Optimal Tuning Strategy and App at a larger scale that can be experienced. After a discussion with the entire Thermal Mass and Buoyancy Ventilation Research Project team, including partners at McGill University and Rural Studio faculty, everyone found the Human Scale experiment is not necessary to validate the Optimal Tuning Strategy. The data from the Chimney Experiments is primo and the team can move on to designing a permanent, Inhabitable Structure. The Inhabitable Structure will be a usable example of the effects of coupling thermal and buoyancy ventilation in a building as well as being a mechanism for producing data. Rural Studio will be able to use the spaces on the day-to-day, but it will also show people the system works and can be applied in the community. While the team has thoroughly enjoyed learning about design through crafting an experiment, they are excited to get back to architecture! There is still plenty of science to come, don’t be fooled.

Balancing science and design seemed like too big a job for 4 students, 2 cats, and a Copper so the team hired a new pet intern. Meet Sonic! He was found at just 4-weeks old out on a county road with only his thoughts and half a tail. As you can see, he is getting along great with the other interns and doing some great sketching. Stay Tuned for updates on Inhabitable Structure design and the teams myriad of four-legged friends.

Thermal Imagination

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.

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.

Thermal image of Dijon the cat

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!

Wood you believe we did it?

Timber pun prepared and deployed? Scientific apparatus built? Yes to both! Live from HomeLab, the Thermal Mass and Buoyancy Ventilation Research Project team is proud to present to you, the Wood Chimney Experiment! No science lessons today folks, just photos.

Students posing with their test chimneys.

SPOILER ALERT! On the left, you see our tried and true, the one who taught us so much, the Concrete Chimney Experiment. On the right, the Thermal Mass and Buoyancy Ventilation family welcomes their newest member, the Wood Chimney Experiment. Now let’s look at the building process.

The top and bottom insulation blocks are created by adhering two 6″ x 3′ 7″ x 3′ 7″ to make them 1″ thick. If you would like a reminder on why this insulation is necessary for the experiment phase and not necessarily for an actualized building you can read this post. The airflow cones are carved out so that they align with the airflow opening of the chimney interior chamber.

Here we’ve got the chimney walls coming together! Four sandwiches of ZIP sheathing, GeoFoam, and Wood Thermal Mass Panels all attached to create an interior chamber.

Three walls up, the fourth needs its sensors! The TMBVRP team thinks it would be absolutely wonderful to be in a space surrounded by edge grain wood that is also naturally ventilated.

The Sensirion airflow sensors will also be in this experiment. Incorporating how sensors can be attached within the chimney and their cords can make it out of the chimney without being squished is a crucial part of the design.

Before the Wood Chimney Experiment interior chamber is sealed, the fourth wall containing the temperature signal sensors must be attached. The temperature signals, read about temperature signals here, will be sensed with thermocouples and heatflux sensors. Next step in the process will be building up the insulation surrounding the interior chamber.

The Thermal Mass and Buoyancy Ventilation team is aware they used to refer to these scientific apparatus as “Desktop Experiment’s”. Technically the inner chamber could stand on a desk, but a more appropriate name might be Carport Experiments or Taller than the Team Experiments. Let’s just call them the Chimney Experiments for clarity. These experiments are still the first and smallest experiments for the scalable Optimal Tuning Strategy. And look, the Wood Chimney Experiment is done! Batt insulation and 2″ GeoFoam walls encase the interior chamber and ZIP tape is used to seal the entire experiment.

Students posing with their test chimneys.

Thank you to all who have encouraged and supported the Thermal Mass and Buoyancy Ventilation team! The team is very excited to have reached this point, but the work is no where near over. It will take time to learn a new data retrieval and analysis workflow for the new sensors. The team is excited to get to it, but first we are going to celebrate our Wood Chimney Experiment! Cheers y’all and STAY TUNED!