for many years with hot water at about 1000C.
 In order for district heating to be successfully applied on a large
 scale, the systems should utilize cogenerated heat from large power plants.
 However, these plants are presently located approximately 80 km away from
 the urban centers. This necessitates the development of long distance,
 low cost transport systems. It would also be advantageous for the transport
 systems to include thermal storage capability to allow for load variation.
 Increasing the temperature of the thermal transport medium, to 200-2600C,
 would decrease cost of the system and provide an opportunity to serve
 large industry process heat requirements. A research program is needed to
 develop such a medium temperature transport system with significant storage
 capacity, such as use of molten salts, organic, or heat pipe technology.
 There are many other possible improvements in district heating technology
that would enhance its implementation by reducing cost and simplifying
installation. Such needed improvements include advanced materials and
designs for building and waste heat recovery heat exchangers, reliable and
inexpensive energy meters that are feasible to use with individual apartments,
and development of smaller distributed cogeneration plants such as fuel cells
or the coal-fired atmospheric fluidized bed technology.
 Other improtant research needs include placing a potential community
district heating project in proper perspective with respect to energy
conservation measures that can be applied to individual buildings and other
local goals and programs that would compete for capital funds. Many of the
nation's cities find themselves in serious financial difficulties caused by
out-migration of business and people, a dwindling tax base, and spiraling
costs for providing services. Energy, while perhaps not a primary cause of
urban problems, continues to increase rapidly in price and the supplies of
petroleum and natural gas promise to become increasingly uncertain. Some
cities have included energy in their planning process and additional cities
will undoubtedly feel the need to do so in the future. Most cities lack
technical expertise for considering energy conservation options, and the
concept of local community-wide systems (such as district heating) are not
generally well understood. A more important lack of understanding, however,
is the relationship between local energy issues and community conservation


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