Send in the engineering troops
CSE: Have you worked on such facilities in the United States and abroad? If so, what are some of the most notable differences?
Talbert: Facilities outside the U.S. have historically placed a greater emphasis on fire-resistive construction and a lesser emphasis on active fire protection such as sprinkler protection.
Bomboy: In addition to our domestic military facilities, we have worked on military bases in Egypt, where the challenge was to design the buildings simply enough, using standard components, so that replacement parts and repair service could be obtained when needed. For military projects, most of the MEP equipment is procured from U.S. manufacturers. However, electrical power in most overseas locations operates at 50 Hz versus 60 Hz in the U.S., and has different delivery and usation voltages; equipment specifications must be carefully tailored to address these differences. Limited availability of skilled local labor and language issues drove an increased level of detail required for successful bidding and construction.
Callan: I have experience working on military and Dept. of Homeland Security projects in the U.S. and abroad. Because these facilities are usually subject only to U.S. codes, regulations, and institutional standards, the main challenges for MEP engineers are climate, utility provisions and their reliability, and available materials and labor.
Crance: We deliver many different project designs both domestically and overseas. The challenges with delivering overseas projects depend on the sponsoring agency and its project goals. Projects supporting country building or redevelopment are often required to be designed around locally available materials and products that will be constructed using locally available craft labor with greatly different skills than we are accustomed to in the U.S. Other considerations for delivering overseas projects include movement of material and equipment across multiple borders, lack of documented codes and standards, and widely varying business practices, both formal and informal.
CSE: What cutting-edge energy efficiency projects have you worked on at a military facility recently? What design aspects or products were included?
Valdez: The RAIDRS Space Control Facility at Peterson Air Force Base in Colorado is a new two-story building and is a mission critical facility. Unique features of RAIDRS Space Control Facility include the use of a transpired solar collector system, and an accessible floor displaced air distribution system. Transpired solar collectors or solar walls are used as a thermal preheat system, providing passive preheating of outside air in the winter months. Energy codes require high ventilation loads, which represent an enormous energy expenditure given the tremendous volume of outside air that has to be continuously brought in and then heated over the entire heating season. A solar wall system consists of panels that are mounted roughly 6 in. from the exterior south-facing wall of the facility’s main mechanical room. The cavity created between the exterior wall and the solar wall panels fills with outside air that is heated by the radiant heating of the panels. The heated outside air in the cavity is then drawn into the air handling units in the mechanical room and reduces the amount of thermal energy that is needed from natural gas.
Bomboy: Every military project has an energy-efficiency requirement, so most projects take advantage of a combination of energy conservation measures. Our designs have used dedicated outside air systems (DOAS) with energy recovery heat wheels, radiant heating and cooling in floor slabs, condensate recovery, and solar hot water systems. We have also performed energy recovery to preheat domestic hot water by capturing heat energy from shower drains. Efficient lighting systems and lighting controls—task lighting, LEDs, zone controls, etc.—figure into all our designs. In some cases, rooftop photovoltaic (PV) systems have also proven cost-effective. Recent projects make use of GSHP systems to reduce a facility’s annual energy consumption. Depending on geographic location, some of these systems are incorporating supplemental heat rejection capabilities in the form of dry coolers or evaporative cooling towers to address the heating/cooling load imbalance. Other recent projects use solar water collectors to offset energy use associated with heating domestic water. Air-side energy recovery is implemented through use of air-to-air energy recovery systems where dedicated makeup air units are used to enhance energy recovery efficiency. These applications are being incorporated on both domestic and overseas projects.
Callan: The projects I have worked on were more utilitarian in nature. While energy conservation has always been of primary concern, we achieved these goals with modest investments.
CSE: How has the military’s emphasis on “net zero” systems affected your work on such projects?
Callan: I applaud the Army’s desire to pursue net zero goals. The army has been a leading force in many areas including science, engineering, and education. Net zero energy buildings (NZEB) are an achievable goal with perseverance and time. However, like my grandfather said, “it’s the journey, not the destination.” My personal engineering philosophy is one of continuous improvement. Some changes will be small and gradual. Some changes will be monumental. Though I agree with the late Daniel Burnham, who said, "Make no little plans. They have no magic to stir men's blood and probably will not themselves be realized," I recognize that many of the engineering feats of today were perfected with gradual and continuous improvement. In other words, no matter how great the goal or objective, the first attempt will be refined and improved over time.
Current new construction and renovation projects focus on conservation of both energy and water as most of these projects are single facilities. Opportunities to achieve the benefits of waste energy reuse or energy repurpose are limited by the scale afforded by single facilities. For many projects, it is challenging to incorporate the most beneficial systems into the facility design and remain within the first cost constraints of the project. Looking forward, it should be expected that larger-scale projects that provide a total energy solution at an overall installation level will be required to achieve the net zero vision.
Bomboy: The first step to achieving net zero is to reduce energy consumption. Whether a project has a net zero goal or not, it is important to find cost-effective alternatives for driving down the building energy consumption; photovoltaic systems and solar hot water panels are common considerations. To achieve true net-zero performance, it is essential that MEP collaborate closely with architecture to optimize building footprint and orientation, fenestration, building skin performance—passive or active—and light shelves/shading, in order to treat the building not as a collection of components, but as a coordinated system.