Net-Zero Energy in Single Family Residential Projects: Leveraging Sefaira Concept to Design High Efficiency Affordable Housing

Transcription

1 Net-Zero Energy in Single Family Residential Projects: Leveraging Sefaira Concept to Design High Efficiency Affordable Housing Sefaira Concept helped The Miller Hull Partnership perform energy simulation modeling on a pro-bono project for Habitat for Humanity Seattle-King County

2 2 The Customer The Miller Hull Partnership, established in 1977 by David Miller and Robert Hull, is an architecture firm based in Seattle and San Diego. The firm is recognized as a national leader in sustainable architecture and was awarded the American Institute of Architects Firm Award in In 35 years and with hundreds of millions worth of completed projects, Miller Hull s work base is composed of a diverse assortment of project types from neighborhood park structures to a $577 million border crossing. Miller Hull specializes in projects such as schools, higher education facilities, nature centers, community centers, mixed-use buildings, laboratories, and corporate offices. In addition, the firm is noted for the design of innovative and affordable residences. The Project: House of the Immediate Future The Miller Hull Partnership, Habitat for Humanity Seattle-King County, and the Seattle Center Foundation Next 50 partnered to design and build the 2012 House of the Immediate Future. The house was meant to be a counterpart to the House of the Immediate Future Exhibit held at the 1962 World s Fair in Seattle. Construction of the house at its initial display location in the shadow of the Space Needle began last April. Upon the close of the Next 50 celebration, the house was disassembled and is now being reconstructed at its permanent home in New Rainier Vista, a transit-oriented neighborhood in Rainier Valley. Both phases of construction utilized Habitat s methodology of community engagement and volunteer labor.

3 3 The Challenges The House of the Immediate Future s program required long-term operational affordability, which could be achieved by designing for netzero annual energy consumption. Due to the non-profit nature of the undertaking, all project participants worked on a pro-bono basis. As such, the design directives were determined via fast-paced, collaborative Think Tank workshops, where over 60 local experts could have maximum input in a short amount of time. The team generated strategies that could be universally applied to other nearterm Habitat projects by focusing on the immediate component of the design challenge, and seeking the right blend of established but forward-looking building systems and construction techniques. The result of this collaborative process produced a number of potential strategies that then had to be analyzed, validated, and prioritized at a negligible cost before they could be worked into the design drawings. The Project In Situ

4 4 The Solution Sefaira Concept for Real-Time Sustainability Analysis Miller Hull used Sefaira Concept to rapidly model heating and cooling loads for four distinct design cases: Compliance with the local residential building code Improved envelope performance above and beyond code compliance High-efficiency HVAC added to an improved envelope Rooftop photovoltaic panels added to high efficiency HVAC and an improved envelope To execute the four models, Miller Hull was required to enter into Sefaira Concept only three global inputs: the project s location, the house s usage profile, and a simple SketchUp model of the building itself. Next, the architects created individual concepts for the design cases, each one a slight derivation from its predecessor. As displayed in Sefaira Concept s comparison report on page 5, Miller Hull modeled Design Case #2 (named HP Envelope Load Calc) by adding the following to the Design Case #1 (Code Baseline); improved glazing via reduced thermal transmittance (U-factor), a tighter building envelope via lower structural leakage, and improved thermal resistance (R-value) in the walls, roof, and ground floor. The Design Case #3 (Design Case) enhanced sustainability even further by improving the HVAC system from electric resistance space heating with a coefficient of performance (COP) of 1, to an air to water heat pump with a COP of 4.6. The addition of photovoltaic panels to 86% of the roof is projected to contribute 3,678 kbtus to the house s primary electricity needs. Add the 28,445 kbtu that could be exported back to the grid, and the design for the house can be confidently considered net-zero.

5 5 Sefaira Concept s Comparison Report Code Baseline HP Envelope Loads Calc Design Case

6 6 The Result By limiting the heating load through tightening of the envelope, and then satisfying that load with high efficiency HVAC equipment, Miller Hull was able to reduce the House of the Immediate Future s energy use intensity by (EUI) 38%, from the base concept to the final design. With the most efficient design identified and verified in Sefaira Concept, the continued design process produced a buildable result that was first constructed for display by both professionals and volunteers in the shadow of Seattle s Space Needle. The house s reconstruction in a transit-oriented development in South Seattle is currently under way, under the auspices of Habitat for Humanity Seattle-King County. With photovoltaic panels added to the roof, the project has the potential to become a net energy generator for the new owners. - Jim Hanford AIA, LEED AP Energy Specialist at The Miller Hull Partnership KEY BENEFITS Sefaira Concept s detailed building physics data validated the project design Sefaira Concept s robust analysis engine enabled the calculation of multiple strategy combinations Sefaira Concept s cloud-based technology facilitated a quick cycle per iteration, limiting Miller Hull s energy modeling expense on the project

7 7 About Sefaira Sefaira was founded in 2009 with a mission to promote more sustainable buildings by helping the building industry design, build, operate, maintain and transform all facets of the built environment. Sefaira s proprietary cloud-based technology, built upon deep building physics expertise, offers an integrated approach to sustainable design analysis, knowledge management, and decision support. Sefaira helps designers analyze and compare sustainable building strategies for new build or retrofit projects in a fraction of the time and cost previously required. By providing sophisticated analysis via an intuitive web interface, Sefaira helps users define, quantify and optimize the energy, water, carbon and financial benefits of relevant design strategies. Sefaira s offices in London and New York have supported projects across the US, Europe, the Middle East and Asia. CONTACT SEFAIRA SEFAIRA (US) +44 (0) (UK) info@sefaira.com FOLLOW SEFAIRA linkedin.com/company/sefaira twitter.com/sefaira Copyright 2013 Sefaira Ltd. SCO200C-01