Waipahu Intermediate School Cafeteria
Size: 19,200 sq. ft.
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Waipahu Intermediate School's Cafeteria has a cavity roof to siphon out warm air for energy efficiency and comfort.
"It is a beautiful cafeteria...it's much cooler in the dining area than in the old cafeteria... much cooler because of the way it is designed and the way the wind blows through."
Randell Dunn
Principal
Waipahu Intermediate School
BACKGROUND:
The Waipahu Intermediate School (WIS) Cafeteria is a new full-service cafeteria and multi-use facility for Waipahu Intermediate School, and is the first sustainable/LEED® project undertaken by the State of Hawaii. The 19,200 square foot facility is designed to serve up to 750 students at a time, and replaces an outdated serving cafeteria that is only one-third its size.
As a pilot sustainable/LEED® project for the Department of Education, the WIS Cafeteria demonstrates the State’s willingness to lead by example in its commitment to conserve environmental resources and seek ways to provide better facilities for public schools.
PROGRAM:
The program for the Waipahu Intermediate School Cafeteria can be summarized as follows:
- To provide a new, full-service, sustainable cafeteria facility for Waipahu Intermediate School that is highly functional, maintainable, energy efficient, and provides a comfortable and healthy environment for dining and multi-use activities by both the school and the public.
- To achieve a LEED® NC v2.1 Certified rating, as awarded by the U.S. Green Building Council.
The program of spaces for the facility includes:
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- Dining/Multi-Purpose With Permanent Stage
- Conventional Cooking and Serving Kitchen With Four Serveries
- Staff Dining
- Boys/Girls Restrooms
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- Boys/Girls Dressing Rooms
- Custodial Service Center
- Storage
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APPROACH/DESIGN CONCEPT:
The design objective of the Waipahu Intermediate School DOE cafeteria is to provide a facility that both meets Department of Education (DOE) criteria and demonstrates the effectiveness of sustainable design as a means of conserving resources, reducing operation and maintenance costs, and providing a better and healthier environment for occupants. Ultimately, the project seeks to demonstrate the compatibility between sustainable design and DOE goals and objectives for functionality, cost, maintenance, and operations.
The design features of this facility that make it unique among DOE cafeterias are its daylighting design, and the dining area roof that functions as a thermal chimney to drive stack-effect ventilation. As a result of these two design features, the need for ceiling fans and electric lighting in the dining area, otherwise standard features in DOE cafeterias, is eliminated (during school business hours). Thermal comfort is maintained at all times by natural means alone.
Daylighting effectiveness is made possible by shaded north and south facing clerestories and jalousies that are designed to bounce indirect daylight deep into the dining area.
The roof of the cafeteria’s dining area is designed as a thermal chimney, which moves air entirely by thermo-dynamics (hot air rises) without the need for mechanical assistance. Solar radiation heats air in the plenum cavity between the roof and insulated ceiling. This heated air flows upward and is exhausted out of four penthouse-style “chimneys” at the high point of the roof. Replacement air from outside is constantly drawn through the dining area into a series of engineered vents in the ceiling, providing thermal comfort. Air changes created by this stack effect exceed code minimums. This system continues to function effectively in the evening, fueled by the heat produced by occupants and electric lighting. (Click here to view a flash animation of the thermal dynamics of the cafeteria's roof.)
SUSTAINABLE DESIGN APPLICATIONS:
The sustainable design aspects of the Waipahu Intermediate School Cafeteria are summarized below:
| Site: |
Proximity to public transportation
Bicycle storage and changing rooms
Minimal development footprint
Divert 98% of construction waste from landfill
No light pollution or trespass |
| Flexibility and Long Term Value: |
Multi-Purpose dining area is also used for student performances, staff and faculty meetings, and public meetings, and after-hours functions such as dance, exercise, martial arts, etc. |
Low Energy and High Performance: |
Overall energy consumption is 15% less compared to a code-compliant base case
Full Commissioning
Thermal comfort
Daylight and Views |
| Daylighting: |
Use of daylighting in the dining/multi-purpose space reduces electric lighting use in that area by 58% |
| Natural Ventilation: |
Use of effective stack-effect and cross-ventilation eliminates the need for ceiling fans and maintains thermal comfort |
| Water Conservation: |
Use of drought-tolerant native landscaping and drip irrigation reduces potable irrigation requirements by 63% |
| Materials: |
Emphasis placed on use of local materials (concrete, CMU)
Use of low to no-emitting paints, adhesives
Use of Certified Wood |
| Recognized Rating Systems: |
Project registered for LEED® NC v2.1 Certified rating |
Performance Metrics:
| Item: |
Base Case: |
As Designed: |
Savings: |
| Irrigation |
5,130 gpd |
1,918 gpd |
63% |
| Lighting |
653,756 kWh/yr |
272,261 kWh/yr |
58% |
| Dining Fans |
3,110 kWh/yr |
0 kWh/yr |
100% |
| Energy (Overall) |
2,458,646 kWh/yr |
2,077,151 kWh/yr |
16% |
CONCLUSION:
The project can claim a number of sustainable achievements that benefit Hawaii and reduce the bottom line. Of equal importance is that the new cafeteria now provides a comfortable and healthy environment for the students, faculty, staff, and public who use it.
For more green building design information on the Waipahu Intermediate School Cafeteria, please visit:
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FERRARO CHOI AND ASSOCIATES
Sustainable Architecture, Interior Architecture, and Research
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HONOLULU, HI 96813-4016
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FAX: (808) 599-3769
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LAST UPDATED: 02.07.2008 |
