Department of Defense (DoD) installations must operate critical missions while facing various causes of electrical utility outages, yet the current utility infrastructures in most bases are vulnerable to such outages. Although microgrid technology is effective in obtaining energy resilience, the cost and time for the microgrid design and installation is prohibitive in military installations. Therefore, a disaster-resilient building operation scheme is demonstrated to sustain critical military missions when buildings experience limited or no power supply, by using the distributed power generation sources, thermal storage in the buildings, and demand-side management of building end electricity users. Specifically, the technical objectives of this demonstration project were to evaluate the initial costs, operation, and maintenance costs of the disaster-resilient and energy efficient building operation scheme in a real-world DoD installation and validate the performance to enable direct technology transfer and commercialization, making the technology available to Tinker Air Force Base and across DoD.

The implemented disaster-resilient and energy efficient building operation scheme contains the following technologies: on- and off-peak demand management through optimal chilled water (CHW) storage tank charge/discharge operation; load-density based air supply house (ASH) unit rotation schedule to strategically reduce/curtail heating, ventilation, and air conditioning (HVAC) equipment usage when the power supply is limited; and energy-efficient HVAC operation sequences to acquire HVAC energy savings through optimizing system operations. The implemented energy efficiency measures include optimal outdoor air intake control, cooling tower fan control, optimal secondary CHW pump operation and system/equipment tune-up.

The demonstration involved performance validations for the resilience algorithm and energy efficiency measures. Through 15-minute whole-building level power measurements and one-minute interval operational data, it is concluded that 14% peak reduction was obtained by using an on- and off-peak demand management algorithm and an average of 7.65% electricity savings was obtained in the cooling season. The average annual total cost savings is estimated to be $111,592 based on the lumped utility rate of $0.05/kWh. It is worth mentioning that all the savings were obtained through soft corrections on the system operation sequences without hardware replacements. The total cost of technology implementation was $223,910. Therefore, a simple payback is two years.

The ASH units in the demonstration site have configuration constraint that in summer operation, supply air fan speed cannot be reduced to lower than 60%. Although the challenge was mitigated by reducing the number of ASH unit operations, the configuration constraint generates an operational challenge for humidity control in the indoor space. During the project, the indoor humidity was monitored through portable humidity sensor provided by the University of Oklahoma team. It is recommended to install permanent humidity sensors in the future. In addition, the proposed CHW storage tank charge and discharge operation was developed and tested using a constant set point to obtain a flat daily demand for resilience purposes. The resilience algorithm can be operated using different set points to obtain other performance goals if desired.