| The State of New Jersey created The School Construction Corporation (SCC) to plan and execute its $8.6 billion program mandated by state’s Educational Facilities Construction and Financing Act. The SCC has adopted Executive Order #24 on sustainable designs, which states: “All new school designs shall incorporate the guidelines developed by the United States Green Building Council (USGBC) known as Leadership in Energy and Environment Design LEEDTM Version 2.0 to achieve maximum energy efficient and environmental sustainability in the design of schools.”1
SCC further esta blished 26 LEEDTM points as the minimum requirement for sustainable design but did not require that school buildings be filed for LEEDTM Certification. Newark School District is planning to register its schools with USGBC in order to take advantage of available rebates.
The LEEDTM requirements for design and construction generated a momentum amongst architects and engineers to come up with practical ways to obtain 26 LEEDTM points while meeting the construction budget of each school. SCC has set the following cost-per-square-foot bench marks for different grade schools: primary schools–$206, middle schools–$212 and high schools: $218.
PB’s Role in Newark School Program
PB is serving as a partner in the PB+3DI joint venture program management firm (PMF) responsible for managing the design and construction process of Newark District’s 73 schools.2 Newark has some of the most antiquated school buildings in the country, with many of them having been built an average of about 90 years ago. Most of these schools have never had a major renovation. As part of this program, 42 of these schools will be replaced, with the majority being on new sites.
At the early stage of design while the conceptu al schemes were being prepared, we conducted design charettes with participation of all the stake holders to address issues regarding LEED criteria and points. The results of these meetings and the strategies developed collectively to achieve the required number of LEED points are described below.
Design Strategies
Designers for Newark District schools concentrated on the following strategies to achieve the required 26 LEEDTM points required by the client and meet the budget:
- Sustainable Sites. Total LEEDTM points: 14. Newark schools average 5 to 6 points.
Strategies: Being in urban areas, Newark schools are usually accessibly by good public transportation. Also, by planning at least three-story buildings, which raises density ratio of the immediate neighborhood above the average density, LEEDTM designers gained points for urban redevelopment.
- Water Efficiency. Total LEEDTM points: 5. Newark schools average 1 to 2 points. Strategies: Waterless urinals were introduced into the schools, irrigation systems for schoolyards were eliminated and indigenous plants were introduced for landscapes.
- Energy and Atmosphere. Total LEEDTM points: 17. Newark schools average 5 to 6 points.
Strategies: Engineers have come up with strategies in the areas described below to gain additional points over those that are usually achieved by adopting ASHRAE/IESNA 90.1 and using non CFC-based refrigerants in HVAC equipment. These strategies also supported N ewark Public Schools’ interest in achieving long-run savings in ever- increasing energy costs and maintenance costs. (See the cost issues below for long-run savings and capital costs.)
– Ground water energy source. Three new schools that are under construction have been designed within a geothermal field, and a few more schools in the design phase will use a ground water energy source.
Characteristics:
System: Closed water loops
Ground: Solid rock beyond 3m to 7.5m (10 feet to 25 feet) of depth (rock usually provides good conductivity and it is preferred by drillers as a predictable material)
Field sizes: 1 acre to 1.5 acres providing 300 tones to 400 tones of cooling load
Well depths: 120m to 135m (400 feet to 450 feet)
Design: NPS requires both heating and cooling options in winter and summer so individual heat pumps are implemented at all educational spaces. Large spaces (gyms, cafeterias, and auditorium) are served by individual conventional units.
– Heat recovery units. All of the new schools have either conventional or active desiccant heat recovery equipment for their fresh air and exhaust system regardless of their cooling and heating systems.
– Ice Storage. Ice storage has been implemented in a few schools to complement the geothermal field or to reduce the chiller sizes on direct absorption of electric chillers.
- Material and Resources. Total LEEDTM points: 14. Newark schools average 5 to 6 points.
Strategies: Most new schools will be built on new sites that have existing buildings on them. Waste management strategies are implemented for demolition of these structures. For instance PB+3Di introduced 25 percent recycling requirement for all demolition contract into the bidding documents of existing buildings on school sites. Most of LEEDTM points in this area can be gained with little impact on construction cost.
- Indoor Environmental Quality. Total LEEDTM points: 15. Newark schools average 8 points.
Strategies: Indoor air quality policies such as daylighting and dimming systems and the use of low emitting materials were introduced with minimal cost effect, but the implementation of ASHRAE 55 for thermal comfort monitoring proved to add to the building cost.
Daylighting in schools is the most critical item of design. It has been the subject of many studies and research and has become the mandated requirement by a few states in the U.S. New findings state that daylighting can improve students’ scores by 20 percent, making it a forefront issue for designers and educators.
In order to have tangible effect of daylighting on electrical and mechanical loads, 70 percent of school time should receive daylighting in all educational spaces. Defused daylighting could reduce cooling load of schools by 20 percent. Implementing daylighting in gymnasiums, the most used space in schools, is fairly easy and inexpensive.
Electrical controls including the dimming systems are often implemented. These controls can be costly, however, especially the dimming equipment, so they are usually at the top of the value engineering list for elimination when projects face cost overruns.
• Innovation and Design Process. Total LEEDTM points: 5. Newark schools average 1-2 points.
Strategy. One point was earned by having a certified LEEDTM professional on the design team, and some schools earned a second point by incorporating sustainable design into the curriculum of the school.
Cost Issues
Some of the points discussed above are earned with no cost penalties but most have a capital cost impact. The life cycle analysis was based on the use of schools during the summer months because, like many urban-area schools, Newark schools are moving toward year-round schedules. In addition, many schools are used as community centers in the evenings. Our team performed an independent estimate and then reconciled the cost differences between our results and those of the designers.
Daylighting is the most important factor of sustainable design in schools affecting performance of the students. It and geothermal are the most used design strategies in our schools. The cost implications of each are described below.
Geothermal Fields. For an average school size of about 13 000 m2 (140,000 square feet) a mechanical system incorporating geothermal field and heat pumps with simultaneous cooling and heating capability system will cost about $800,000 to $1 million more than conventional roof-top mechanical units. Different life cycle analyses showed that the maintenance and running cost of a geothermal/heat pump mechanical system will be 20 to 25 cents less expensive per square foot than a conventional system.
Daylighting. Daylighting strategies could add $1.50 per square foot to the construction cost, but it is believed that these costs would be earned back within four years and that from then on savings in energy costs would be realized.
A full implementation of the above energy saving systems in the schools could potentially reduce the running and maintenance cost of mechanical systems by 30 percent.
USGBC publications state that the green initiatives should not add more than an average of 2 percent to the construction cost of the buildings. Our analysis and estimates so far show that strategies discussed above, if implemented fully, could add about 5 percent to the overall construction cost. In the Newark area this would be about an additional $10 per square foot. Our life cycle analysis, based on 4 percent yearly increase in energy costs, has shown an average 15 to 20 years payback by the energy and maintenance savings period for the 5 percent initial capital cost.
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