Chiller #2 Replacement

Added: Mar 08, 2018 5:39 pm Modified: Apr 05, 2018 12:14 pmTrack Changes

The USDA Headquarters (HQ) in Washington D.C. consists of two buildings - Whitten and South Buildings. The Sub Central Plant (SCP) is a standalone one story building located on the south side of the Whitten Building's West Wing. The SCP is half underground with its main entrance on the north side. To access the SCP, one has to take the outdoor stair at the back of the Parking Lot 10A (see attached photos)

The SCP houses two chillers and each has its own cooling towers. A project in 2011 replaced Chiller 1 (the new Chiller 1 is a 350 ton York Centrifugal chiller with R134a refrigerant) and its cooling towers, motors of Chiller 2's cooling towers, two condenser and two chilled water pumps, water treatment system, and controls. The new pumps are all equipped with variable frequency drive (VFD); the towers (1A and 1B; 2A and 2B) have VFDs too. The new controls are direct digital type connected to a remote Building Management System (BMS; Johnson Controls Metasys). Also included in that 2011 project is a new free cooling system via Cooling Tower 1A and 1B, a standalone plate heat exchanger, and a separate condenser water pump. The free cooling mode is activated manually through a remote front-end of the Johnson Controls building management system (BMS) located in the Wing 2 Sub Basement of the USDA South Building.

The current Chiller 2 (Trane, 350 ton ice capable chiller) was replaced in 1995 in the Thermal Storage System (TSS) project. The TSS has its own glycol pumps and plate heat exchanger; Chiller 2 made ice at night for the TSS up until 2008. The TSS stopped running (due to economic reason and chronic glycol leaks); subsequently, Chiller 2 was used to generate chilled water only, up until 2011, when the new and more efficient Chiller 1 became the primary chiller and Chiller 2 was reduced to a backup role. Currently, the Building Operations Branch runs Chiller 2 occasionally to keep it in shape. Chiller 2 has outlived its life expectancy.

 An organized site visit will be held on Friday March 23, 2018 at 10:30 AM ET at the USDA South Building, 1400 Independence Avenue SW, Washington, DC 20250. Use Entrance 3 near the arch which is the visitor's entrance. Check in with the guard. Contact Joseph Brown on 202-720-0537.

Added: Mar 08, 2018 5:39 pm

The USDA Headquarters (HQ) in Washington D.C. consists of two buildings - Whitten and South Buildings. The Sub Central Plant (SCP) is a standalone one story building located on the south side of the Whitten Building's West Wing. The SCP is half underground with its main entrance on the north side. To access the SCP, one has to take the outdoor stair at the back of the Parking Lot 10A (see attached photos)

The SCP houses two chillers and each has its own cooling towers. A project in 2011 replaced Chiller 1 (the new Chiller 1 is a 400 ton York Centrifugal chiller with R134a refrigerant) and its cooling towers, motors of Chiller 2's cooling towers, two condenser and two chilled water pumps, water treatment system, and controls. The new pumps are all equipped with variable frequency drive (VFD); the towers (1A and 1B; 2A and 2B) have VFDs too. The new controls are direct digital type connected to a remote Building Management System (BMS; Johnson Controls Metasys). Also included in that 2011 project is a new free cooling system via Cooling Tower 1A and 1B, a standalone plate heat exchanger, and a separate condenser water pump. The free cooling mode is activated manually through a remote front-end of the Johnson Controls building management system (BMS) located in the Wing 2 Sub Basement of the USDA South Building.

The current Chiller 2 (Trane, 350 ton ice capable chiller) was replaced in 1995 in the Thermal Storage System (TSS) project. The TSS has its own glycol pumps and plate heat exchanger; Chiller 2 made ice at night for the TSS up until 2008. The TSS stopped running (due to economic reason and chronic glycol leaks); subsequently, Chiller 2 was used to generate chilled water only, up until 2011, when the new and more efficient Chiller 1 became the primary chiller and Chiller 2 was reduced to a backup role. Currently, the Building Operations Branch runs Chiller 2 occasionally to keep it in shape. Chiller 2 has outlived its life expectancy.

 An organized site visit will be held on Friday March 23, 2018 at 10:30 AM ET at the USDA South Building, 1400 Independence Avenue SW, Washington, DC 20250. Use Entrance 3 near the arch which is the visitor's entrance. Check in with the guard. Contact Joseph Brown on 202-720-0537.