Aerial view of solar photovoltaic (PV) panels on the new Child Development Center at Parris Island, S.C. The facility is equipped with 1,134 PV panels, each rated at 245-W for a total capacity of 275-kW. Photo Credit: Aero Photo
The new Child Development Center at Marine Corps Recruit Depot, Parris Island, S.C., is the first structure on the base, and possibly the entire southeastern United States, with the ability to achieve Net Zero energy—the capacity to produce all the electricity that it will use. The facility, which provides care for children of some of the 2,500 Marines and sailors permanently stationed there supporting the basic training program, incorporates a host of innovative sustainability features and is currently pending LEED Gold status by the Green Building Certification Institute.
The Department of Defense Education Activity (DODEA) carries the ambitious goal of reaching energy independence in its buildings in support of Executive Order 13514, which requires all future federal government buildings to achieve Net Zero energy use by 2030.
The U.S. Navy’s mandate, as established by Secretary of the Navy in October 2009, is to have 50 percent of energy consumed in its installations—which include Marine Corps locations—to come from renewable sources by 2020. And though not a specific requirement of the Parris Island Child Development Center when Naval Facilities Engineering Command (NAVFAC) Southeast awarded the project to Sauer Inc., in September 2009, the importance of on-site renewable energy as a means of reducing electricity use became evident from the onset.
Design-build team members tasked with designing and implementing sustainable and energy-saving measures comprised VOA Assoc. Inc., for architectural and interior design; Van Wagenen and Beavers Inc. for the mechanical, electrical and plumbing systems; and a construction management team from Sauer. The group began with, and remained focused on, selecting the most cost-effective and energy-efficient systems the project could afford while still achieving the most LEED points possible. Test wells showed that implementing geothermal energy would be a good starting point, to be followed by adding solar thermal and solar photovoltaic (PV) systems.
Exterior view of new Child Development Center, including playground area and solar photovoltaic (PV) panels. The facility is designed to blend with the historic architecture of Parris Island, employing brick detailing accent brick, corbelling and recessed panels. Photo Credit: Paul Keyserling Photography
The historic Marine Corps Recruit Depot at Parris Island is nestled in the southern tip of the South Carolina low country. The base was established in 1915, with its primary mission to train all new enlisted Marines east of the Mississippi River. Today it supports a population of 2,500 Marines and sailors permanently stationed supporting the basic training program. The new child development center is designed to blend with Parris Island’s architecture, employing brick detailing that utilizes accent brick, corbelling and recessed panels, which reflect the historic buildings constructed during World War I. The single-story facility cares for infants, toddlers, pre-toddlers and pre-school children ages six weeks to five years old—accommodating about 250 children and 65 staff members.
The building’s envelope utilizes masonry construction for maximum advantage of the heat sink effect. It is encapsulated in a continuous layer of R-10 rigid board insulation. The roof is maintenance-free. Standing seam metal panels, R-30 insulation with 3-ft overhangs and a cool gray finish reflect solar heat back into the atmosphere. An all-electric kitchen—necessitated by the lack of natural gas service—makes it easier to verify energy consumption. The child development center’s location within a hurricane zone also dictated “large missile” impact resistant laminated glazing. That application compliments the additional blast hardening required by the recent Department of Defense “Minimum Antiterrorism Standards for Buildings,” since the uncontrolled building entrance drop-off is within the minimum standoff distance of 82-ft.
Additional sustainable features include water-saving plumbing fixtures, high-recycled product content, and locally and regionally manufactured materials. The building’s mechanical systems include geothermal ground source water-to-water heat pumps for heating and cooling. Domestic water heating systems have a solar hot water system rated at 51-kW and a ground source heat pump water heating system. PV panels rated at 275-kW are estimated to produce all of the building’s electricity needs. Lastly, all activity rooms are equipped with daylight harvesting systems, which maximize the large windows and skylights by dimming the light fixtures during daylight hours.
Mechanical and Geothermal
To reduce dependence on fossil fuels, and impart a highly energy efficient approach to heating and cooling the center, a geothermal closed loop concept was developed.
Covered parking structure at the entrance of the building includes canopy solar photovoltaic (PV) panels. PV panels mounted on the canopies not only provide electricity to the building but they double as covered parking. The exterior of the building and the parking lots are lit with light-emitting diode (LED) fixtures, which are expected to save 10 percent to 20 percent more energy than traditional exterior lighting sources such as fluorescent or high-intensity discharge (HID). Photo Credit: Paul Keyserling Photography
The design incorporates a variable flow geothermal closed loop system, with a bore field of 73 vertical u-tube wells of approximately 275-ft in depth. Geared to adequately support the systems for 50 years, this long bore field life comes from a nearly balanced heat flow resulting from rejected heat from cooling systems being offset by heat withdrawal for the hydronic and domestic water heating systems. And because the younger children in the facility use the floors as their main activity platform, the activity rooms are heated by floor hydronic radiant heating systems for added comfort.
The building’s hydronic heating system incorporates three, dedicated 276,200-Btuh hot water generators. They satisfy all heating requirements associated with the variable air volume (VAV) air distribution systems, via a variable flow hot water circulation system and the radiant heating system.
Hot water returning from the terminal unit heating coils and the various utility space unit heaters supply the radiant floor heating systems. For cooling purposes, the geothermal loop serves a water cooled self-contained packaged VAV air conditioning unit with a capacity of 889,000-Btuh and an 86,000-Btuh water-to-air heat pump for the kitchen area. The self-contained, packaged VAV provides conditioned primary air to each of the occupied spaces through shut-off style VAV terminal units. There are minimum primary air valve positions for maintenance of minimum ventilation flow rates. All the outside air for ventilation and exhaust make-up is preconditioned through a central energy recovery unit. A total enthalpy wheel and integral supply and exhaust fans each with variable speed drives are controlled by duct mounted static pressure sensors.
Additionally, two water-to-water hot water generators—each with a capacity of 122,000-Btuh—are used to provide domestic water heating, with a supplemental solar domestic water heating system providing 60 percent of the demand. The domestic hot water system incorporates two, large hot water storage tanks: a 1,500-gal tank for the water-to-water system and a 600-gal tank for the solar domestic side of the system.
Electrical and Solar PV System
The Child Development Center is equipped with 1,134 PV panels, each rated at 245-W for a total capacity of 275-kW. Mounting the panels on the parking canopies not only provides electricity for the building but they double as covered parking and can be adapted to most sites. There are three PV inverters that connect directly to the building service transformer for maximum efficiency. The estimated maximum electricity generated by the system is 387,581-kWh per year. When combined with the electricity saved by the solar water system—which is 50,430-kWh per year—this all-electric facility will generate the totality of its estimated consumption.
The interior lighting is also designed to save energy. All fixtures are energy-saving fluorescents with energy-saving ballasts. All rooms with skylights and exterior windows are equipped with daylight sensing/harvesting systems.
Parking lots and the exterior of the building are lit with light-emitting diode (LED) fixtures. These are expected to save 10 percent to 20 percent more energy than traditional exterior sources, such as fluorescent or high-intensity discharge lamps (HID). Exterior LED lighting retrofits can be accomplished in existing facilities with minimal occupant interruption.
With the recent military budget reductions, the future of Net Zero energy goals may seem uncertain. However, many new development centers or schools can be designed and constructed as “Net Zero Energy Ready,” with minimal impact to the initial cost. In this manner, all passive energy saving features are designed and constructed into the original architecture; and only construction of the infrastructure for adding future on-site renewable energy options such as solar PV or wind turbines is included.
As the cost per-KW of solar PV panels continues to drop, achieving Net Zero with infrastructure already in place will become easier. Fortunately, the project at Parris Island was awarded during a construction cost downturn, making the sustainability pursuits even more achievable and cost effective. The Child Development Center has exceeded all expectations and will become a showcase facility as the Marine Corps’ first Net Zero building at Parris Island.