2013 ASHRAE T TEcHnology AwARd cASE STudiES Above DESS HDPE pipe being thermally welded. Left Newly constructed Athletes' Village prior to residential use. Treated sewage is pumped from the existing treatment plant to an adjacent mechanical plant room, where it is filtered before passing through a bank of heat exchangers. A two-pipe, reversed return, closed-loop system around the Athlete's Village supplies the energy required for all of the heat pumps in Phase 1 of the project. Water from the heat exchangers in the mechanical plant room is pumped through high density polyethylene piping, around the distribution loops, providing the energy source for the heat pumps within each of the Village buildings. There are no circulating pumps or control valves between the connected building supply and the return to the DESS. Control is entirely governed by the pressure difference between the supply and return mains. The heat pumps in each unit were selected to provide 60% of the peak capacity for heating and/or cooling, with electric heating elements installed in each building as backup. The largest pipe at the discharge from in the system mechanical room is 14 in. (356 mm) in diameter. Phase 1 flow from the mechanical room is maintained at 1,600 gpm (101 L/s). Flow rate for the completed system will be 2,400 gpm (152 L/s). Space has been reserved for a future heat exchanger and pump. Two gas-fired standby boilers are located in the mechanical room. www.info.hotims.com/44638-44 O ct O b e r 2 0 1 3 ashrae.org ASHRAE JouRnAl 41