The West Berkeley Public Library (WBPL) is a new 9,339 square foot structure located in a vibrant mixed use neighborhood of Berkeley. With a construction cost of $7.5 million, the project was completed under budget in October 2013. The facility is designed for a maximum of 252 occupants.
The design gives the library a more prominent position on the street, increasing its visibility in the community. The library serves a diverse population and features programs for adults, teens, and children. Its large collections of Latino, East Indian, and Asian material reflect the cultural diversity of the neighborhood.
In 2009, the City of Berkeley published its Climate Action Plan, seeking to reduce its Green House Gas emissions to 33% below 2000 levels by 2020. Upon auditing its building portfolio, the city realized the only way to achieve this goal would be to have all new city buildings achieve ZNE performance. The city decided to begin with a library, funded by Berkeley residents under a bond issue, and issued an RFP.
Harley Ellis Devereaux prevailed as the winning design team on the strength of its proposal for a ZNE design – the only ZNE proposal received. In addition to being responsive to Berkeley’s policy objectives, the proposal also addressed State of California ZNE policies, which call for all new residential and commercial new construction to be ZNE by 2020 and 2030 respectively. PG&E, a large utility serving northern California, launched its ZNE Pilot Program in 2010. The WBPL was selected as a ZNE case study for the PG&E program. PG&E provided funding and became a partner in supporting the analytical and modeling work.
HED works in a highly iterative, integrated and collaborative process requiring all key design members and stakeholders remain engaged as strategies are evaluated and refined throughout the life of a project. A number of public workshops were initiated, where community input was sought, ideas proposed and multiple design charrettes held with active community engagement before the concept design was moved forward by consensus. Extensive building simulation modeling and studies were carried out by our in house HED/Greenworks team members. Since in many cases they were one and the same, it allowed for design ideas and strategies to be tested quickly, resulting in an efficient holistic process. These studies included:
- Site and climate analysis.
- Plug load, energy usage and available renewable energy generation analysis.
- Solar insolation studies to determine the optimum roof height for maximum solar gain and minimal solar access encroachment.
- Computational fluid dynamics studies to study the effectiveness of the wind chimney in drawing fresh air through the building.
- Thermal comfort verification of staff offices and adult literacy.
HED lead and managed the process throughout all stages of the project. They understood that to achieve a ZNE facility in a public bid process would require a highly integrated design and should be driven by architectural passive design solutions to control costs and lower long term maintenance. The majority of the engineering consultants including HED (at that time) were firms local to Berkeley and highly respected. These included the civil, landscape design, and structural engineering. Their knowledge of the city and their passion for it is exemplified in the quality of the design. Mechanical, Electrical and Plumbing engineering was two phased with Timmons Design involved in the design phases and HED carrying it through bid- construction. Project challenges included the tight urban setting and high traffic area. Through an exploration of various design strategies, the team came up with an innovative design balancing the needs of the community and site restrictions with its energy efficiency goals.
The building footprint utilizes approximately 75% of the site and places constraints on landscaping. In the northwest corner is a small garden court with a mature cork oak three and medium density shrubbery. There is a long planter along the entire west wall with vines trained to vertical cables that will one day cover most of the west façade. The landscaping is drought resistant and many of the plant species are native to the region. Located on the south, north and west of the building are infiltration planters designed for onsite storm water treatment through low flow planters.
High Performance Building Approach:
Energy use reduction through architectural design incorporating passive strategies was the key approach. Berkeley is blessed with great weather and abundant sunshine, which allowed the design team to focus on designing a high performing energy efficient structure that leveraged both natural ventilation and solar access with daylighting and renewables.
Natural Ventilation- Heating & Cooling:
Mix mode of solar thermal with three small heat pumps and a condensing unit on the roof for heating and cooling.
The Building’s BMS (Building Automation/ Monitoring System) controls the PV, natural ventilation, fans, radiant heating and cooling. The lighting panel controls are tied to the BMS.
Computer Fluid Dynamics (CFD) models were generated to study the characteristics of air flow in the building.
The radiant flooring consists of triple wall pex tubing that are embedded in a 4” concrete slab over 2” of rigid insulation on a 18” thick concrete mat slab.
Heating and cooling:
There are 5 mix modes for natural heating and cooling in the building:
Heating mode: Solar Thermal collectors on the roof provide heat to the radiant slab. If there is insufficient sunlight, supplementary heating is provided via heat pumps located on the roof.
Required air exchanges (fresh air intake) are achieved with preheated air passing through Runtal radiators at the exterior windows.
These operable windows are opened and closed by the Building Management System (BMS) which utilizes sensors within each space to detect elevated levels of carbon dioxide.
These windows can be opened manually for added individual control but the BMS will perform a sweep at predetermined times and close the windows as necessary to ensure energy is not wasted.
Cooling mode 1: Early season- Cool outside air is drawn through building utilizing negative pressure at the wind chimney to extract warm interior air. The standard air flow is from the operable windows at the north, through the building and up the wind chimney.
In addition to carbon dioxide sensors, there are thermostats within each space or zone that monitor the temperature of the room and communicate with the BMS.
Should the temperature exceed or fall below set points, the radiant system will initiate.
There are manifolds located in certain areas that control the separate radiant zones.
Cooling Mode 2: Moderately warm –Cooling mode 1 plus additional air movement achieved by opening operable skylights.
The skylights are controlled by BMS.
Cooling Mode 3: Warm – Modes 1 & 2 with additional air movement utilizing large fans in interior spaces and supplementary exhaust fan at wind chimney for heat extraction.
The large bladed fans are controlled by the BMS and individual remote controls.
Cooling Mode 4: Hot- All windows and skylights are shut. Supplementary cooling provided through radiant floor via heat pumps on roof. Windows are opened by BMS for fresh air intake as required.
Extensive daylighting models.
Artificial lighting is tied to lighting panels and daylight sensors.
Task based versus spatial illumination.
Together these highly integrated design solutions enable the West Berkeley Public Library to perform above expectations. The buildings true EUI is 24.1 kbtu/sf-yr. It produces 1,744kWh excess energy annually and this will allow the city to provide free electric vehicle charging as a community service. There is no natural gas to the building and it is truly a Geeen house gas free building. The library was recently certified as a Living Building Challenge V3.0 Net Zero Energy Building in April of 2015, making it the first public library in the state of California to achieve this difficult certification program. It was recently honored with the BDA Design Awards, a local community driven design excellence program, highlighting the positive impact this project has had on it’s community.