Researchers determine whether geothermal pumps can lower costs at waste water treatment plantsNovember 03, 2010
Engineers from the University of Illinois at Chicago are investigating whether sinking geothermal heat pumps into waste water treatment plant aeration ponds can provide heating and cooling to lower the plant's energy costs.
The two engineers plan to test two types of heat pumps at the Metropolitan Water Reclamation District of Great Chicago's James C. Kirie plant in Des Plaines, Ill, according to a new s release from the university.
The project will take place over the next year. Sohail Murad, head of chemical engineering at UIC and the project's principal investigator, said he hopes it will " determine the feasibility of harnessing energy from the effluent water." The demonstration could determine which system can reduce the plant's heating and cooling needs by 20 percent -- and that's without further refinements.
The project will test both "open" and "closed"-loop geothermal heat pump systems.
Heat pumps collect heat during the winter months through fluid circulating in pipes called loops, placed underground or in a body of water. The circulating fluid carries ground or water-stored heat indoors. In summer, the loop draws away indoor heat and carries it underground or underwater, where it is absorbed. In a closed loop system, the circulating water or other suitable fluid stays inside the pipes. In an open loop, water from the pond, instead of the circulating fluid, is pumped in and out of the system.
"Open and closed-loop pond systems are not very common, so development work has to be done to establish optimal operating parameters," said Murad, who specializes in thermodynamics. "We'll also test if the treated water leads to any corrosion or fouling issues in the pipe in the open system."
The project will use treated water that exits the plant into adjacent aeration ponds.
Catherine O'Connor, the Metropolitan Water Reclamation District of Great Chicago's assistant director of monitoring and research, said the project is novel and there is no documentation of a side-by-side comparison of an open versus closed-loop system that recovers heat from reclaimed water effluent.
Cost of the $175,000 project will be covered in part by an $87,500 grant from the Illinois Clean Energy Community Foundation. UIC will handle process design. Other costs include the purchase of two 15-ton heat pumps with ancillary equipment to augment the current building heating and air conditioning system.