The innovative features in this new library include a daylight-filled floor plan, a natural ventilation tower, and the use of insulated concrete panels to keep the interior cool in the warm summer months.
The library sets a new standard for sustainability in a civic building, and meets Leadership in Energy and Environmental Design (LEED) Gold certification requirements. Three major sustainability objectives, set by the architects and the library, shaped the design: 1) maximize daylighting; 2) increase the building's thermal mass, and 3) exceed California Energy Code Title 24 by over 25 percent.
The design began as diagram that was all about light. While walking around the site, the designer sketched a V-shaped roof that rose up to bring in natural light on both the north and south sides of a structure.
From that initial diagram, the design team created a vibrant, welcoming building that mimics the shape of an open book and lets in as much natural light as possible, reducing the need for artificial lighting and fostering an environment conducive to learning.
The design team collaborated with the library building committee to maximize square footage and provide daylit spaces for patrons and staff. Working from a program that outlined distinct service areas, the design team organized the interior spaces along a steel "spine," continuing the imagery of an open book. The spine orients the patrons to the facility, and allows them to view into distinct spaces for children and teens, three group study areas, a learning centre, and a computer lab with internet and word processing. Generous spaces, now common in libraries, include a community meeting room that can accommodate as many as 100 people, and a food court for refreshments and socialising.
By strategically orienting the building on the site, with the long facades facing due north and due south, the architects were able to capture the ideal amount of daylight while shielding the glazing from direct sunlight. The tilted roof also provides an ideal roof angle for photovoltaics. The design team selected a building-integrated photovoltaics system, which consists of attaching solar laminates directly onto the standing seam roof. This cost-effective approach is visually unobtrusive and, when fully installed, will provide an estimated 12 percent of the building's energy.
Energy consumption was further reduced by incorporating insulation into the building's concrete tilt-up slabs. Concrete tilt-up construction has traditionally been an efficient and rapid method of building warehouses and other commercial buildings in the area. The design team wished to explore this method on a civic building and to insert insulation into the large concrete slabs to preserve interior heat. This application is without precedent. No traditional computer simulation existed to calculate the thermal benefits of insulated tilt-up concrete walls. The architects won a design team incentive grant from the local Sacramento utility company's "Savings by Design" program to commission additional modeling analyses, proving this method's high thermal capabilities. The thermal mass feature is enhanced by the addition of a mixed-mode displacement ventilation system that allows natural air to cool the building at night.
As a result of these sustainable design elements, the Valley Hi Library will exceed California Energy Code Title 24 by 34 percent, nine percent more than the original target. Its light-filled design, punctuated by a cheerful red tower that marks the children's reading room, provides a welcoming landmark in the community.