Merit Award
Tiburon, CA 2018
Tiburon Treasure is a project with a sustainable approach not only in terms of building performance but also improving the user experience through the creation of an iconic environment for learning about ecology, biology, restoration, and oceanography, all in the context of sustainable design. Inspired by its unique location, this project pays careful attention to preserving the site values without interrupting the future program of the RTC.
The key factors that were considered for siting the project are proper building orientation for the solar access, maintaining the remarkable views to and from the wharf, providing universal access to the building and making the building geometry as a natural extension of the site to minimize its impact.
Since the project is located on Bayside, the risk of flood is considered during the design process. The flood maps show that most flat part of the site will be eventually at risk of flood. The higher levels on hills will be in a safe zone even in a 500-year period.
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The psychometric chart for the site indicates a climate that is cold and very humid for most of the year. The main challenge, therefore, is how to heat the space. Since most of the hours during the year have plotted in a small area, it was deemed easier to use passive strategies rather than attempt a very diverse or energy intensive design solution.
According to the analysis, the climate can be considered within comfortable conditions for 36.3% of the time. Although the analysis also indicates no extreme heat stress during the year, the moderate to extreme cold condition remains the key challenge for this environment. Because of the high humidity, the thermal condition is predicted to fluctuate very little and the cold condition spread throughout the year, specifically early in the mornings and late in the afternoons.
By comparison the blue charts, it's clear that the most efficient passive strategy throughout the year will be internal heat gain and passive solar heating.
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The first big idea of this project is to embed the building into the ground in order to preserve energy while providing a large facade toward the south to increase solar heat gain. This facade needs protection during summer and also solar penetration during winter. The shading system provides these needs and also provides a surface for PV panel installation. Because the roof tiers are stepped with the slope of the terrain, this increases the roof footprint by 10% which is crucial for solar energy collection, but also provides a great view to the outside. Additionally, an advantage of a greater sloping roof area that this project envisions is that of rain water collection.
The second big idea of this design is combining the requested program into the one building in order to achieve greater efficiency. The program has been divided into three levels. Spaces like an interactive exhibition, administrative offices, multipurpose room and storage are located on the upper levels. The main wet spaces such as wet lab classrooms, restrooms and kayak storage are located on the lower level, reducing the energy consumption that would otherwise be required to pump water to the upper levels.
The first consideration to locating the building mass is by exploring the potential of a site with multiple levels that provide diverse views and access to the project.
The geometry of the building is embedded into the sloping ground and acts as a natural extension of the surrounding topography, providing the maximum access without blocking views. This type of footprint is especially beneficial in terms of the building energy performance.
To preserve the existing vegetation, the construction is intentionally sited in the zone without trees.
The building connects two levels of the site without additional pavement. At the upper level, the existing parking is conceived as a temporary arrival point and drop-off area for public transportation. The lower level is located at the intersection for visitors who arrive by cars or by water as well as for those traveling toward the north shoreline.
*Hover to see the entire site
The first challenge by locating the building on a slope is the access to the building.
The main stair that connects two levels of the site extends into and through the building to provide internal circulation as well. Public areas such as the observation deck, picnic area and stair itself can serve the visitor independent of the building operations.
While the outside ramp provides accessibility to the observation deck, picnic area and visitor center entrance on the top floor, an internal elevator provides accessibility to all levels as well.
The two building programs combine into a single building not only to share the public space but also to enhance the building energy performance by reducing the exposed surfaces and infrastructure. As a result, the two entrances were conceived such that the upper entrance primarily serves the Visitor Center while the lower entrance serves the Science-On-the-Bay program. Although all spaces are interconnected, the Science building program has an internal separation that can isolate this program as needed.
The clear focal point of the building is an observation deck: a huge cantilever extending over the main volume of the building containing a stair that defines the entrances and connection between the upper and lower levels. This dominant gesture presents the building to its surroundings and establishes visual connection with the ocean beyond.
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This daylight simulation is done by Honeybee plugin to demonstrate the percentage of the time during the active occupancy hours that the test points (in this case 3’ above the floor) receive between 100 to 2000 lux. As it was predictable, the daylight level is very high for most spaces close to the south facade. On the Second floor, all of the main exhibition space receive a very good amount of the daylight. The only problematic space that in %10 or below receives less than 100 lux is north part of the wet lab which will require artificial lighting.
For shading inside, a passive system with fixed blades is used and as the final rendering results show, the system is successful in protecting inside of the building during summer and enabling solar access during the winter.
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OpenStudio is used as energy simulation tools. Since the threes sides of the building are inside the ground, these surfaces defined as adiabatic surfaces which are very helpful to preserving the energy inside the geometry. Also, the HVAC system design very efficiently to use ground source pipe in term of reducing the size of the system and also energy consumption. To calculate the amount of electricity that is generated by PV, the NREL PVWatt calculator used with premium module types and 00 for array tilt.
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