PANAMA CITY, Fla -- Naval Surface Warfare Center Panama City Division engineers are developing tools to enable U.S. Marine Expeditionary Forces to accurately predict energy consumption needs in theater.
The NSWC PCD Expeditionary Systems Division engineers were asked by Marine Corps Systems Command to reduce the energy consumption of Marine Corps Combat Operations Centers.
Marine Corps Systems Command acquires and provides life-cycle support of ground weapon and information technology systems.Leaders from MARCORSYCOM and NSWC PCD analyzed combat operations centers, and noted that almost 70 percent of all the energy was being used to heat and cool shelters. The first problem to be addressed was the prediction of shelter heat transfer. This predictions was based upon vendor specifications and calculations.
In July 2012, Steve Gorin, the E30 senior systems engineer, visited the National Renewable Energy Laboratory, located in Golden, Colo., to determine if they may be able to help.
Gorin observed a new heat transfer model being used by the laboratory for building evaluations. The laboratory conducted the modeling and NSWC PCD conducted the validation testing. Not only did the model work, but it proved to be accurate. Their model prediction varied from the measured by less than one degree Celsius of error over the span of several days.
Given the shelter modeling, a large part of the energy consumption could be accurately modeled. The engineers then determined that the power consumption of the equipment could be easily measured, but were concerned about its heat output. Any heat output by the equipment required additional air conditioning.
“We measured the heat output in a lab environment using a calorimeter that we created,” Gorin said. “We measured pieces of equipment within a shelter that might be used in an operational environment, such as computers, monitors, and lights.”
The heating and cooling of the shelter was where the majority of energy was being consumed, improving the energy efficiency started with these factors. The shelter model is physics based on variables such as: shelter material, colors, radiant barriers, air vents, shades, and air infiltration rates.
The engineers evaluated variances, one being how much air is being lost due to air gaps in shelter assembly and traffic in and out of the shelter. What they discovered with a tracer gas test is that the infiltration rate was 10 times greater with one door unzipped than with the tent sealed.
The NREL modeled a shelter with a radiant barrier and predicted a 26 percent decrease in heating or air conditioning energy consumption .
“This new computerized model allows users to incorporate shades, radiant barriers, and tent colors into the heat transfer calculations to determine the need for heating and air conditioning,” Gorin said.
The new model utilizes a weather input file, which can predict tent temperatures anywhere in the world allowing field units to predict supply needs before deployment. Gorin said the new algorithm and model have been shared with the U.S. Marine Corps and the U.S. Army for consideration.
Gorin’s team have since further expanded their efforts and have a computerized model which allows them to predict energy consumption in theater. Gorin’s team has since built an energy compound in Panama City, Fla., that incorporates potentially improved tactical field energy technologies.
“We’re also looking at hybrid energy systems that will enable the Marines and the Army to match their supplies to demand,” he said. “Unlike your house, where you only pay for the energy you consume, the military fires up a generator that is frequently lightly loaded and wastes energy.
“The hybrid system’s aim is to use the generators efficiently by turning the generators off when not needed and using stored or renewable power.”
The Energy Team is presently completing an analysis of alternatives for hybrid power systems that will result in a new power systems for the Marines. One of the hybrid solutions is a Army micro-grid that utilizes six, 60 kw generators that are switched on or off as needed. NSWC PCD is expected to receive one Army micro grid for project testing in the summer of 2013.