District Energy Options Evaluating District Energy Systems
Edward L. Morofsky
A District Energy System, or DES, has a number of recognized advantages
when compared with decentralized units. These include the increased
combustion efficiency obtainable with larger plants; the ability
to burn less costly, higher-energy fuel than most individual heating
plants; the more efficient performance of central plants owing
to continuous operation and professionally maintained equipment;
and the reduction in total plant capacity required to cope with
the varied timing of individual loads. Despite high initial capital
costs, these advantages result in lower life cycle financial and
energy costs, when district energy systems are well designed and
located
appropriately.
Several Canadian circumstances have affected the development
of district energy systems. Extensive use of hydro power, representing
well over half the present Canadian capacity, has
resulted in fewer thermal generating stations near urban centres.
Future generating capacity is likely to contain a decreasing percentage
of hydro power (EMR 1973) as total electrical demand grows and
suitable hydro sites diminish in number and ease of development.
Accordingly this trend will present opportunities to locate future
thermal stations at sites with good DES potential. The existence
of significant summer cooling demands in many Canadian cities
increases the potential Evaluating District Energy Systems annual
usage of a DES and the associated savings.
Recent increases in fossil fuel prices have prompted renewed
interest in district energy systems since the savings in fuel
costs can be used to off-set some of the network costs. Heat losses
have
been reduced by recent improvements in piping hot and chilled
fluids. Furthermore, it seems clear the DES’s are compatible
with many of the strategies that have been proposed to deal with
the energy crisis, from utilizing waste heat to recycling urban
wastes.