Hawaii Preparatory Academy Energy Lab

As a zero net energy and water building with a total floor area of 6,100 square foot, the Energy Lab received a LEED for Schools Platinum rating in October, and in late April achieved full Living Building Challenge certification—only the third such project to do so. The “Challenge,” a program developed by the Cascadia Green Building Council and widely regarded as the most demanding green building certification system, requires that energy needs be satisfied on-site from renewable sources and that all of its water come from precipitation or from a closed-loop system. The program also prohibits the use of the potentially toxic substances on its “red list,” many of which are commonplace in construction materials. In addition, it places limits on the distance from which products can be shipped in order to reach a building site. In all, 20 “imperatives,” or prerequisites, must be met for a project to be designated as “living.”

 

To make the most of the site's natural assets and satisfy the project's goals, the team developed a scheme made up of three long and narrow volumes that step down with the landscape and open to views to the south. These volumes echo the materials and structural systems of buildings elsewhere on campus: They have walls of boards and battens and poured-in-place concrete and roofs supported by wood decking spanning glue-laminated beams. The uppermost barlike element has a double-pitched roof canted so that it nearly touches the ground and deflects the strong wind from the north. The two lower volumes are sheltered under gently sloping shed roofs with deep overhangs that shield the interiors from heat gain.

 

In addition to providing shelter from the elements, the roofs also provide surfaces for energy production and rainwater collection. The two shed roofs incorporate 27 kW of generating capacity, with three types of photovoltaics (PV), including a 4 kW array of bifacial panels (a type of PV in which the back face generates electricity from ambient light reflected off surrounding surfaces). The precipitation that falls on the roofs feeds a 10,000-gallon storage tank that provides water for hand washing, toilet flushing, janitorial needs, and irrigation.

 

The energy-conservation and energy -generation strategies have proved so effective that in the first year of operation, the building consumed only a little more than half of the power predicted by the design team's model, and exported 25,285 kWh of electricity produced by the PVs to the campus grid (about 60 percent of the power generated). Exhaust fans, intended to augment the natural ventilation scheme, have so far not been needed. And a backup split air-conditioning system, included in the building primarily to keep sensitive lab equipment cool in extreme conditions, has also never been used.

 

The vigilance also plays a significant role in the lab's efficiency. The BMS, depends on about 600 sensors distributed throughout the building that monitor everything from CO2 levels, temperature, and humidity to power generation and consumption. It automates the operations of many of the building's systems and gives real-time information about such factors as energy generation and use. It even can identify specific equipment that has been left on mistakenly, such as a printer or the UV lamps that students use for experiments.

 

The sustainability-centric design has proved wildly successful. In 2010 the Lab had - 60% energy usage, meaning the HPA saved $10,200 by feeding this energy into the rest of the campus. 100% water neutral, the Lab collects all of its water from precipitation and treats all wastewater onsite. A specific mixed mechanical and natural ventilation system was developed to reduce operating costs and cooling loads. The 27kW photovoltaic array on the roof generated 48, 295kWh of electricity in 2010 and is connected to the national grid via the rest of the campus to distribute or store excess electricity production. The holistic design is controlled by an innovative building automation system. The system continuously logs and monitors data in occupied zones, reacting by optimizing the lab’s performance through its energy systems. The living laboratory is powered by renewable energy, with solar panels on the roof and a couple small-scale wind turbines on the hill behind the school. The Energy Lab actually only uses 8% of the power it generates, while the rest is fed into the grid and goes to power the rest of the buildings at the academy, making it a zero plus facility.

 

The most subjective of the Living Building Challenge performance areas is ‘Beauty’. The category refers not only to aesthetics but also to harmony with location, environment, and culture. Flansburgh Architects and the school chose three native phrases to organize and express their ideas for designing beauty in a lasting way. Ike (sense of place), Kuleana (responsibility or territory), and Ohana (family or community) are evident in the building's use of materials, relationship to the site, and the mission of the school. The school's location in one of the most beautiful places on earth also naturally adds to the project's beauty.