Author: RS Thermal Mass Team

Graduate Team Completes Construction and Publishes Paper!

The Thermal Mass and Buoyancy Ventilation Research Project (TMBV) graduate students have concluded their work and time in Newbern, AL. In their wake, they leave a published, peer-reviewed paper and two research-ready buildings.

In the course of their graduate year, the TMBV project dove deep into the results of their initial small-scale experiments, culminating in a research paper published in the Journal of Physics: Conference Series as a part of the 2021 CISBAT Hybrid Scientific Conference. At the same time, the team designed and constructed two Test Buildings. The cooling and ventilation effects spurred by the optimized thermal mass will be studied throughout the next year, providing ground truth data for the system at a building scale.

The paper: A synopsis

The open-access research paper entitled, “Synchronized coupling of thermal mass and buoyancy ventilation: wood versus concrete” was published in November 2020 in the Journal of Physics Conference: Series. This was an effort involving the entire TMBV research team including Salmaan Craig, Remy Fortin, Sebastien Asselin, Kiel Moe, David Kennedy, and Andrew Freear. The paper describes small-scale experiments that test the accuracy of sizing parameters which suggest how to optimize the coupling of an internal thermal mass—which allows a building to store heat and thereby avoid major temperature fluctuations—with natural ventilation cycles, regardless of the material or the scale of the building. The results suggest the sizing parameters may be valid for early-stage design. They also show that biomaterials, such as wood, can perform as well as conventional thermal mass materials, such as concrete.

Why is this important? Typical, mechanical thermal comfort systems pump greenhouse gases into the atmosphere, raising the temperature even more. They also cannot perform in power outages during weather events caused by the ongoing climate crisis. Therefore, using regenerative materials, such as wood, to mitigate rising temperatures without reliance on the power grid suggests sustainable thermal comfort with less burden on the environment. That is an ongoing aim of the TMBV Research Project, and these initial results are an encouraging step. Before such lofty goals can be reached, the TMBV Test Buildings will provide more insight into the capabilities of the system.

The buildings: A summary

As stated above, the TMBV Test Buildings examine the coupling of thermal mass and buoyancy ventilation as a reliable thermal comfort system at the building scale. Currently, the buildings are set up for these first large-scale experiments and will later be fitted out for housing. The buildings are designed to be flexible spaces for ongoing experiments as well as dwellings for 3rd-year students. Therefore, the buildings balance valid experimental conditions, the realities of construction, and the basic needs of college students. One Test Building is powered by a plywood internal thermal mass and the other by concrete. Both buildings are designed to achieve the same performance parameters for temperature dampening and ventilation rate despite their material differences—i.e., the surface area and thickness of the material.

The buildings are the first Rural Studio buildings constructed primarily out of Structurally Insulated Panels (SIPs). Towering over the Supershed on Morrisette Campus they hover 8′ off the ground. Underneath the buildings is a gathering space nicknamed the “Cooling Porch.” During the day it is meant to collect cool air flowing out of the buildings, providing a place to enjoy the systems en masse. Air travels here through the extended chimneys, which increase ventilation speed and denote the building’s function.

With such tight buildings, dependent on accuracy, the team showed out on all the details. From three-week welding sessions to mapping out patterns of old sidewalk scrap to calculating the discharge coefficient of rooftop vent caps, this team investigated every inch. Feel free to peruse the TMBV blog to see the process, but for now here are the results.

The team: An abridgement

What a journey! These kids, ready to learn how to craft a beautiful building, were not expecting a crash course in thermodynamics, experimental design, and scientific discourse. It was an incredible opportunity to do both. Blending design, construction, and scientific rigor was an extremely unique and fulfilling educational experience. And the TMBV team sharing that experience across North America!

Rowe, the TMBV team’s certified best and most patient construction instructor, has moved to Bozeman, Montana, to join Love | Schack Architecture.

Jeff, a master of power tools and 3D modeling, is taking time to further his coding and woodworking skills.

Cory, a most relaxed, renaissance man, is enjoying his stint at the Ghost Residency with MacKay-Lyons Sweetapple Architects Limited, in Lunenburg, Nova Scotia.

Livia, the heart and volume of the operation, has settled in Austin, Texas, working with Rural Studio Alums at Thoughtbarn.

A huge thank you to the faculty and staff of Auburn University Rural Studio, the teams’ student colleagues, the project consultants (including Joe Farruggia!), the donors and teachers of Turnipseed International, and “Crane” Shane of Sweetwater Construction LLC for your time, knowledge, and support. Most obviously and ardently, thank you to the TMBV research conglomerate Salmaan Craig, Andrew Freear, Steve Long, David Kennedy, Kiel Moe, Sebastien Asselin, and Remy Fortin for the stellar work and dedication. It took a village!

This lot loves Rural Studio and all of its people. Hope to see y’all soon.

Bit by bit, day by day

Everything is officially clad! The plywood is cut! The benches are designed! The Cooling Porch is secured! The wiring is installed! The door is installed!

Rowe and Jeff are ticking big items off the Thermal Mass and Buoyancy Ventilation Research Project checklist. Let’s take a look at what the graduate research team has completed in the last month.

Clad

The Cooling Porch ceiling and Bottom Chimneys were clad last as they did not need the articulating man lift to reach. Now that the entire Test Building is clad with bleach-stained cypress, their form reads less like floating boxes and more like floating funnels. While the main function of the chimneys is to increase overall stack height and therefore air velocity within the system, they also signal movement to onlookers. Two wood-clad heat silos at your service!

Cut

Another TMBV jig on the books, this one helps break down large pieces of plywood with precise cuts. Jeff and Rowe designed and built the jig to make all the cuts necessary for creating the plywood thermal mass panels. Like the concrete panels, the plywood conforms to the slanted ceiling of the Test Building. There is also substantially more plywood panels as they cover the walls, floor, and ceiling of the interior.

Secured

Next up, the Cooling Porch finishing touches. Steel plates for future benches were installed in the construction of the Cooling Porch walls. However, the bench material was undecided. The team chose to use the same metal grate used on the stairs and walkway for these breezy benches. Over the next couple of weeks, the benches will be installed and reinforced with a bracket.

Last up for the Cooling Porch, a little tripping hazard prevention. The top course of the Cooling Porch walls were dry-stacked but untethered to the ground. To keep the course in place, the team used Tap Con masonry screws and small metal brackets to link the top course with the rest of the wall.

Powered

As future dwellings and experiments, the Test Buildings need power for people and sensors. The buildings are wired through chases in the SIP, accessible from floor outlets to keep the walls clear.

Last on our list of tasks completed is the installation of the doors! The test fit showed a bit more blocking needed, but the end result looks great!

Cladding, Concrete, Continuing

The Thermal Mass and Buoyancy Ventilation Team’s days of pouring concrete and manning the man lift are over. All of the internal thermal mass concrete panels have been poured, cured, and installed in the Concrete Test Building. Another milestone hit is the completion of the exterior cladding (minus the Cooling Porch ceiling). The team waved goodbye to both the articulating man lift, generously donated to the project by Sunbelt Rentals, and to team member Livia. She journeyed to Austin, TX, to work for Rural Studio Alum Lucy Begg and Robert Gay at their firm, Thoughtbarn. Good luck Liv!

Let’s check out the progress!

Cladding Completion

The team met their goal of finishing all cladding which required the articulating man lift by the end of October. The bleach-stained cypress covers all exterior surfaces including the Chimneys. The team left one side of the cladding longer than necessary. Then they came back with a skill saw and a guide to give one clean cut. This ensured that all corner reveals were exactly 1/2 inch wide.

Interior Optimized

Over 70 1-1/8 inch concrete panels now line the walls of the Concrete Test Building. The team crafted formwork and processes for pouring, transporting, and installing each panel. Behind the panels is 1/2 inch rigid insulation which creates a thermal break from the OSB sheathing during the testing phase. For roughly the next year, the Test Buildings will be unoccupied as temperature and ventilation measurements are continuously recorded. Afterward, the Test Buildings will be prepared for either more experiments or occupation by 3rd-year students living on Morrisette Campus. Check out the nearly complete Concrete Test Building below! Only some buffing and shining to go!

Bonus!

Also in the works as of late is a vent cap for the bottom chimney opening within the Test Buildings. This cap seals the lower ventilation opening shut during winter occupation. Seen below is Rowe welding a frame for the hatch!

Don’t miss Jeff and Rowe’s wonderful Halloween Review costumes. Jeff as his prized Milwaulkee leaf blower and Rowe, a leaf, one of many victims. Keep checking back in as the Test Buildings near completion!

It’s a Cover-Up: Cladding the Interior and Exterior

History professor Dick Hudgen’s TMBV Test Buildings Sketch!

Right now the Thermal Mass and Buoyancy Ventilation team is all about concrete and cypress. They’ve been busy creating and installing the shiplap jointed, 1-1/8″ thick concrete internal thermal mass panels. These panels line the walls of one of the Test Buildings and create the designed cooling and ventilation effects. With Jeff at the helm of formwork building, they’ve completed three out of four panel pouring phases. The panel-making process is separated into phases, so most of the formwork can be used more than once, eliminating waste. Formwork, or molds, are fabricated with precision in the woodshop. The team installed phase 1 before Cory began his journey to Nova Scotia to participate in a residency with McKay-Lions Sweetapple Architects Ltd. Congratulations Cory, we miss you already!

Also on the agenda as of late; exterior finishes! With weather-proofing complete, the team has taken to installing the cladding part of the ventilated cladding system. This system is completed with 8″ and 6″ cypress boards which are protected with Cabot® Bleaching Stain. The stain also helps the wood age consistently in the sun. With Livia cutting and Jeff and Rowe installing, the cypress siding is flying up!

Unseen are the myriad of other little things the team is finishing up such as electrical and grading. The team is keeping the momentum up so stay tuned to see the buildings fully wrapped!

Panel Production

Panel pouring process: Mix concrete, fill form, transfer to vibrating table, trowel, and finish!

Cypress Siding

“Neckdown” Week with TMBV

Live from Fall 2021 “Neckdown” Week, it’s the Thermal Mass and Buoyancy Ventilation Research Project Team (TMBV)–and helpers! This week, the team accomplished a variety of tasks with the help of the 5th and 3rd-year students.

First on the agenda, the team completed the Cooling Porch ground surfaces. This included packing crushed ground surface concrete pieces and building the stairs. The Cooling Porch stairs were comprised of stacked concrete pieces cut from the foundation pour excess. David Hill, professor in Auburn’s School of Architecture, Landscape Architecture and Planning, got in on the concrete saw action! Continuing on the stair action, the team also installed the steel stringer and handrails for the Test Building entry. After pouring a concrete footing for the steel stair, Rowe came back and welded on all the treads.

With all the groundwork in the Cooling Porch finally complete and three sets of stairs built, the TMBV team is calling this “Neckdown” Week a huge success. Thank you to all our helpers this week! Next up, thermal mass concrete panels–stay tuned!

Sneak peek of the Test Buildings at the end of “Neckdown” Week.

Gravel Infill

East Entry Stair

South Entry Stair

Steel Stair