The United States Health and
Human Services (HHS) Headquarters, WASHINGTON, DC
EMCOR Government Services (EGS) was selected by the client for its ability to complete projects on time, without disrupting building operations or occupants.
EGS provided the client with an energy-saving solution through the installation of heat pumps to supplement and optimize the existing steam heat system. The project concluded in September 2016, with a projected $245,000 per year of energy savings and an estimated three and a half year return on investment for HHS.
The United States Health and Human Services (HHS) headquarters was in need of a solution to reduce the cost of steam heating for its nine-story office building. The work necessary to fulfill this goal had to be completed while the building remained fully operational.
The heat pump system project included two phases: Phase One involved conducting a preliminary study to define the scope of work, followed by designing the system. The actual system installment occurred in Phase Two.
During the scoping study, it was determined that significant cost savings for HHS could be achieved by installing heat pumps to recover heat from the return air ventilation and provide hot water for the hydronic heating systems in the building.
Based on the study’s results, a design was created for the installation of 20 heat pump systems on 10 Air Handler Units (AHU) in the building’s lower penthouse. Two COLMAC HPA4 air-to-water heat pumps were assembled on each AHU.
Following the installation, the return air for the AHUs now provides the heat source for the heat pumps. Any cool air passing though the heat pumps is recovered and sent to the return air stream before it is mixed with outdoor air in each AHU. The hot water produced by the heat pumps is sent to the building’s circulating water heating loop, which reduces the need for steam.
The heat pumps’ control system is tied into the existing Building Automation System and is able to sense temperatures of the return hot water in the water heating loop. When the water temperature is too high to be used effectively by the heat pumps, the control system disables them. The heat pumps restart automatically once the water temperature in the loops drops below 120 degrees Fahrenheit.
The control system also detects the temperature of the ventilation return and exhaust air from the heat pumps, as well as the status of the loop in the heating or cooling mode. If the perimeter system is in cooling mode, and the heat pump exhaust air is cooler than the ventilation return air, the cool exhaust air is directed back to the return air stream by the heat pump damper.
With 20 total heat pumps installed, HHS’ annual cost savings in heating is approximately $225,000. Supplementary annual savings of $20,000—or $1,000 per heat pump—for the use of cool air brings the total energy savings to $245,000 per year.
HHS is a cabinet-level department of the federal government. Its mission is to protect the health of all Americans and provide essential human services.
Located in southwest Washington, DC, at the foot of Capitol Hill, the Hubert H. Humphrey Building is 876,035 square feet and serves as HHS headquarters.
EGS currently holds the Operations and Maintenance (O&M) contract for the building, which includes the mechanical, electrical, plumbing, and fire systems equipment, along with snow removal, pest control, and janitorial services.