Build It Green Wins Research Grant to Advance Multifamily Zero Net Energy
Our goal? To solve challenges to constructing apartment buildings that produce as much energy as they consume.
By Don Knapp
The California Energy Commission (CEC) has awarded Build It Green (BIG) a research grant to overcome key challenges to developing zero net energy (ZNE) multifamily buildings. The goal of the CEC grant is to make ZNE construction technically and economically feasible and to accelerate ZNE’s adoption among multifamily developers.
BIG and its research partners will optimize approaches to designing and constructing multifamily buildings that produce as much energy as they consume—through the use of on-site renewable energy and breakthrough all-electric technologies for water heating and HVAC. Four affordable housing ZNE demonstration projects in California will offer opportunities to investigate these approaches in-depth and create comfortable and healthy homes for low-income residents.
“As a green building leader and innovator, Build It Green is thrilled by this opportunity to advance ZNE best practices and show multifamily developers that ZNE is both achievable and cost-effective,” said Karin Burns, Build It Green CEO. “This research project will be critical to helping the state of California meet its goal to make ZNE the standard for all new residential construction by 2020.”
Our Research Team
BIG will lead an all-star team of researchers, coordinated by Senior Technical Manager Amy Dryden. Nehemiah Stone of Stone Energy Associates, a leading expert on multifamily energy efficiency, will serve as Principal Investigator. The Association for Energy Affordability, Redwood Energy, Lawrence Berkeley National Laboratory and NEXI will contribute critical expertise for data collection and analysis. The four all-electric, ZNE demonstration projects—in various stages of design and development—are being provided by the Corporation for Better Housing (CBH) and Resources for Community Development (RCD).
The research project will demonstrate the potential of innovative heat pump water heating and HVAC technologies as a pathway to ZNE, then go a step further to explore the complex, interdependent systems in a multifamily building to show how they can work together to achieve ZNE in a cost-effective manner.
“California’s ZNE goal is approaching rapidly, yet a host of key ZNE design and building science issues remain poorly understood for multifamily developers,” said Bruce Mast, Build It Green’s Chief Innovation Officer. “Our research will help establish design and installation best practices that minimize risks for developers and accelerate the market toward ZNE. We need to ensure that all the potential benefits of ZNE are fully realized, especially persistent cost-savings and greenhouse gas reductions.”
Technical Details and Project Goals
The BIG team will achieve the following design and planning research goals:
- Lower the costs for building multifamily developments to ZNE standards.
- Lower GHG emissions by field-testing 100% electric solutions for cost-effectively achieving ZNE standards.
- Improve electricity reliability by demonstrating load-shifting solutions that increase the energy self-sufficiency of multifamily ZNE developments.
- Reduce planning uncertainty by reconciling design and actual performance for advanced systems and developing new methodologies for quantifying their benefits.
The BIG team will also complete these technology-related goals:
- Water heating: Quantify the economic and performance trade-offs of central versus individual heat pump systems, both for equipment efficiency and distribution system efficiency.
- Storage: Evaluate the potential for thermal storage solutions to reduce demands for grid power.
- Zero net energy: Demonstrate that true ZNE performance with 100% offset can be achieved on multifamily buildings, accounting for limitations in the project footprint.
- Heating and cooling loads: Investigate the economic trade-offs of investments in building shell performance versus mechanical system performance.
- Non-regulated loads: Investigate the technologies and behavioral strategies required to optimize the efficiency and performance of non-regulated loads.
- Code compliance: Develop new analysis algorithms for code compliance software to give proper credit to advanced technologies that support the state’s ZNE goals.
- Human interactions: Research the interactions between building energy performance, health, comfort, and convenience in a multifamily context.
Four Low-Income ZNE Projects
The BIG team will investigate ZNE issues through four demonstration projects that share a goal of all-electric ZNE construction with 100% offset, and provide affordable housing to large, low-income families.
Calistoga Family Apartments
This Corporation for Better Housing (CBH) project provides 48 units of low-rise multifamily farmworker housing in Calistoga. The project incorporates central heat pump technology for space heating and cooling and domestic hot water; onsite chilled and hot water storage for load shifting benefits; and desuperheating technology to optimize the production of hot water and chilled water. Onsite renewable generation is expected to offset 100% of the load. Project research will focus on commissioning to improve performance, evaluating the load shifting benefits of thermal storage, and developing a methodology for accounting for desuperheating benefits in building energy models. Construction is largely complete.
Cloverdale Family Apartments
This CBH project provides 31 units of low-rise multifamily farmworker housing in Cloverdale. Project goals include LEED Platinum certification, Energy Star Indoor Air Plus label, DOE Zero Energy Ready Home, and EPA WaterSense label. The approved permit plan set calls for central heat pump technology for space heating and cooling and domestic hot water. Hot water distribution has been designed to minimize structural plumbing waste. Onsite renewable generation is expected to offset 100% of the load for this all-electric development. Project research will focus on optimizing the mechanical systems, incorporating analysis results from the Calistoga project. This project is in early development.
Atascadero Family Apartments
This CBH project provides 59 units of low-rise multifamily farmworker housing in Atascadero. Onsite renewable generation is expected to offset 100% of the load for this all-electric development and is required to provide "off grid" energy storage, which will be achieved via ice tanks and hot water tanks in concert with heat pump water heaters. Project research will focus on optimizing the mechanical systems, evaluating the load shifting benefits of thermal storage coupled with individual unit heat pumps, and evaluating the impacts of individual heat pumps on distribution efficiency. The project is fully funded and in development.
This Resources for Community Development project will supply 59 units of high-rise apartment housing (six stories) in East Oakland. Developers have committed to achieving Living Building Challenge (LBC) certification, which requires that 105% of the project’s energy needs be supplied by on-site renewable energy on a net annual basis, without the use of on-site combustion. This project is still at the conceptual design phase so it can incorporate lessons learned from the three CBH projects to optimize mechanical system design. In particular, analysis is expected to address the performance trade-offs between central and individual systems.