RETRO-COMMISSIONING ENERGY STUDY AND VRF UPGRADE
MOAKLEY FEDERAL COURTHOUSE, BOSTON, MA
A Re-Commissioning/Retro-Commissioning Study was initiated for the John Joseph Moakley United States Courthouse, located in Boston, MA. The purpose of this report was to document the baseline energy performance of the whole building as well as identification of energy conservation measures (ECMs) of various building systems affecting energy use and indoor environment, including shell infiltration and heat loss.
The survey encompassed the review of major systems and components. These included Air Handling Units, Cooling Towers, Chillers, Pumps, and various Lighting Systems. The building envelope survey which included an infrared thermography survey was also completed.
A building load and energy model was created using TRACE® 700 version 6.2 energy simulation modeling program. This program models energy consuming devices as well as the building envelope effect in relationship to operating hours, efficiency, control, and weather conditions. By establishing the base model of energy usage coupled with historical utility bills, the impact of ECMs can be accurately compared and analyzed. In this manner, BBIX using the NIST BLCC™ 5.3-08 could accurately forecast future annual energy savings against the baseline of historical utility usage and costs.
A building envelope survey was performed, as part of which a building thermography or Infrared (IR) Imaging was conducted. The IR photographs consistently showed elevated heat loss, represented by elevated brick surface temperatures at various locations.
A VRF System Upgrade was implemented as part of the critical ECM’s. The scope of work consistent of replacing the HVAC System on the top two floors of the Moakley Federal Courthouse with a VRF system consisting of variable refrigerant units distributed above the upper level office ceilings. The respective condensing units were served by the building cooling tower system. This energy conservation measure was put in place to improve the energy efficiency of the U.S. Attorney offices located at the Moakley Federal Courthouse. The Government maintained full occupancy of the space during the entire period of construction. Based on the upgrade of the 9th (partial) and 10th floors, the annual cost savings is $271,800.