LA-80-12-1 -- A Community Energy System Supplied from Waste Industrial Energy through Heat Pumps PDF

An integrated community energy system for the city of Everett, Washington, using heat pumps (HPICES) to elevate the quality of waste industrial energy has been identified. A large paper and pulp mill provides the source of low-grade waste energy. The mill operates 24 hours per day, 358 days per year, exhausting 52.6 million gallons per day (200,000 m3/day) of warm water through four outfall lines to Puget Sound.

This plant is centrally located within the city so that transmission pipeline length is minimal. This energy can be applied to satisfy the space heating demand and potable hot water production for the downtown commercial district and surrounding high density residential area. A mix of 40 percent commercial and 60 percent residential subscribers is predicted.

Two heat pumping strategies were considered. The central strategy incorporates large heat pumps located near the outfall "sources", with water-to-air heat exchangers at the subscribers' sites. The distributed strategy incorporates water-to-water heat exchangers at the outfall "source" and heat pumps located at the subscribers' sites. Economic analysis indicates that this energy conservation concept is cost competitive with conventional space conditioning systems over the projected 30-year system lifetime.