Zero Net Energy Student Housing

Date Posted: 11.15.2015

By Brendan Connolly

Mithun’s zero net energy student housing design for UC San Francisco Mission Bay, ESTUARY, received the top 2015 Architecture at Zero Honor Award. Architecture at Zero is a national competition targeted at testing feasible approaches to zero net energy building solutions in urban environments. ESTUARY was hailed by the competition jury for its sensitive attention to placemaking and human experience. The jury also noted the excellent synergy between engineering and architecture to achieve performance goals. The design was developed by Mithun’s multidisciplinary team in Seattle and San Francisco, in collaboration with engineers at PAE.

ESTUARY Design Concept

Inspired by the predevelopment ecology of the Mission Bay estuarine marshes, ESTUARY comprises three residential structures that are shaped and organized by the flow of people and systems. These prismatic building masses envelop a central terraced community courtyard that connects the residents and also the energy and water systems below. A porous site plan allows entry and access to major campus greenway and transit connections, and invites the larger community to circulate through the courtyard spaces. Each faceted residential tower is arranged to offset individual unit views and optimize daylight harvesting and natural cooling, with residential units connected through internal atrium ventilation stack spaces.

ESTUARY weaves together timeless passive strategies and high performance building envelope and renewable energy strategies, including a district heating loop that combines energy collected from the earth, sun and compost and methane sources on and below the site. Most importantly, ESTUARY also seeks to inspire user engagement and responsibility, through a celebration of human actions that drive down energy demand, including inviting external stairways, expressed passive clothes drying, occupancy energy budgets and shared community kitchen spaces. Collectively, these and other strategies encourage stewardship, social engagement and a community commitment to a zero net energy balance.

The Human Experience

Resident comfort and function is at the core of the ESTUARY design. The range of unit types are intermixed to create a cohesive community that blends generational and demographic range of users. Units are accessed via open air atrium spaces within each building, which offer circulation areas that accommodate informal “porch” seating as well as covered bicycle storage and overlook areas that are open to the sky and PV canopy above. The unit planning expresses functional logic and optimized use of space and flow, with abundant access to natural ventilation, daylight and views, and through ventilation to the atrium spaces from the building exterior.

In an effort to drive down plug loads, each unit features a card-activated occupant power switch upon entry that limits ghost loading on circuits, and also dryers are not provided. A 40% Energy Savings over typical residential equipment loads is possible through the activated key card system. All clothes drying occurs via “skyline” exterior clothes drying spaces in the building facade that allow vertical passive stack air movement. These expressed elements reduce energy, and activate the facade through human interaction, weaving a 21st century building with timeless cultural and social sustainability practices.

Positive Change: Residents and Behavior

Building performance depends on positive engagement with residents. ESTUARY inspires stewardship and action through the design of spaces that encourage and reward reduced energy and resource use. These strategies not only drive down the EUI of the building, but they also promote community and interdependency with the social fabric of the project. The design concept shares the story of Pat, one of ESTUARY’s newest residents, to illustrate the layers of user experience and behavior that contribute to the performance of the project.

About Architecture at Zero

Now in its fifth year, the Architecture at Zero competition seeks creative and feasible approaches to zero net energy (ZNE) building. By encouraging innovative design solutions to site-specific challenges, the competition aims to broaden thinking about the technical and aesthetic possibilities of ZNE projects. The 2015 competition site is part of the University of California, San Francisco’s Mission Bay Campus that will be developed with mixed-use residential buildings. The program is hosted by AIA California Council and Pacific Gas and Electric Company.