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Twin Canopy Research Center

Mass timber climate research center with a sky radiative cooling roof

Winner, AIA COTE Top Ten for Students, Category II: Upper Level (2025)

Twin Canopy Research Center
Type
Architecture design
When
Winter 2024
Where
University of Pennsylvania
Tools
Rhino, Grasshopper, Ladybug Tools, Honeybee, EnergyPlus, D5

Twin Canopy Research Center is a two-story, mass timber complex dedicated to supporting climate study as well as providing lodging for researchers. Situated in Woodland, TX, a hot and humid climate, passive cooling is critical for ensuring thermal comfort and energy efficiency. The building takes advantage of the greater energy flows available on the roof and utilizes their large surface areas for two critical processes: longwave radiation to sky for cooling, and solar energy absorption to facilitate moisture evaporation and generate electricity. Specifically, the Sky Radiative Cooling (SRC) Roof addresses sensible heat loads, while the Desiccant-Based Dehumidification Roof is designed to manage indoor humidity. Indoor Radiant-Evapo Cooling (REC) Panels leverage the drier exhaust air to provide additional cooling in peak periods.

Section drawing
Section drawing
Site plan
Site plan

Houston, Texas

The project is nestled within a densely forested, triangular lot in Woodland, Texas. Directly adjacent to the site on the eastern side lies a small pond, offering potential flood mitigation benefits. The surrounding neighborhoods are predominantly residential, with a major east-west highway running along the southern edge of the site.

Double roof system, exploded
Double roof system, exploded
First floor plan
First floor plan

Double roof system

Since the system design incorporates both a radiative cooling surface and a liquid desiccant surface, it is fitting for the project to feature two distinct roofs, each serving a specific function. The geometry of the roof system provides the majority of cooling from the radiative cooling surface. Additionally, the sloped design of the roof enables the liquid desiccant to flow naturally along its surface, guided by gravity, optimizing the system’s passive functionality. The liquid desiccant recharge will only take a small portion of the solar roof and therefore the rest of the surface area can be dedicated to photovoltaic thermal panels that generate electricity during the day and provide additional radiative cooling at night.

The thermal storage underground allows for flexibility in conditioning where radiative cooling might not be most efficient, such as instances where the humidity is high or sky coverage is high. The hybrid system ensures the sensible heat and moisture content is managed as air is passed indoors and allows the building to achieve maximized efficiency through extraction of passive conditioning sources.

Project hypothesis

The hot, humid outdoor air first passes through a liquid desiccant, which absorbs moisture, producing hot, dry air. This air is then cooled as it flows through a cooling coil supplied by the cold storage from the radiative cooling system, resulting in cold, dry air that is delivered to the room. As the air returns from the room, it becomes slightly warmer and drier. To maximize the benefit of the air’s dryness, it is routed through an evaporative cooling device to absorb additional heat from the room. Finally, the warm, humid air is exhausted from the system.

Second floor plan
Second floor plan
Final review board
Final review board
Construction detail through the cooling roof
Construction detail through the cooling roof
Short section
Short section

Architectural experience

The exposed mass timber structure infuses the interior with a natural warmth, complementing the brightly illuminated spaces to create an atmosphere of tenderness and intimacy. The building’s western facade is designed to be relatively opaque, following passive optimization simulations that revealed the need to shield this elevation from intense sunlight. This results in an arrival experience where the building appears to emerge subtly from the woods, with its entrance discreetly integrated into the facade. This design ensures the privacy of the living quarters while instilling a sense of intrigue and anticipation as visitors approach. Upon entering, the double-height co-working space immediately contrasts with the compressed entrance, offering a sense of openness and inviting visitors to appreciate the spatial interplay.

Building energy optimization

The passive strategies for the project include optimizing glazing ratios, particularly on the west and south facades, selecting appropriate window types, construction methods, and enhancing internal thermal mass. The optimization process explores the building’s geometric configuration and its impact on comfort hours. The analysis was conducted in two scenarios: one in an unconditioned setting and another using an ideal air system to evaluate the heating and cooling loads.

The optimization results indicate that mass timber construction is a promising option for the specific climate being studied. It significantly reduces the heating load, making it highly efficient in colder months. While the cooling load is comparatively higher, it can be effectively mitigated through the implementation of a well-designed mechanical system, ensuring year-round comfort and energy efficiency.

Second floor co-working space
Second floor co-working space
Researcher bedroom
Researcher bedroom
Courtyard
Courtyard