Page 40 - Sustainable On-Site CHP Systems Design, Construction, and Operations

CHAPTER 2

Applicability of CHP

Systems

Itzhak Maor

T. Agami Reddy

Background
Combined heat and power (CHP) systems offer great promise in alleviating some of the
looming problems of increased energy demands and peak power issues arising from
deregulation of the electric market, petroleum shortages and the drive for better energy
efficiency. This chapter discusses the applicability of CHP systems for commercial and
industrial applications. Since the terminology used by different publications is confusing
and sometimes conflicting, we start with defining relevant key terms to CHP systems
in general.
The distributed power utility seems to have evolved in four directions:

1. Large-scale/wholesale electric power generation systems (sizes in the range of 400 to
1000 MW), primarily meant to sell power to an electric utility. The sizing of
such microgrid systems is dictated by power purchase agreements rather than
by site requirements of electric power and heat (Orlando 1996).
2. District energy and industrial/agricultural CHP systems (sizes ranging from 3 to
50 MW) for process applications that require almost constant thermal and
electric loads to be met year-round. These systems are meant for industrial/
agricultural process applications (ICHP) and for district energy systems involving
large campuses as well as clusters of residential units in a neighborhood.
3. Building CHP (BCHP) systems (sizes in the range of 50 kW to 3 MW) for individual
buildings and small campuses where the intent is to reduce electric power
purchases from the local utility by either generating electricity on-site and using
the waste heat to reduce boiler heating requirements (topping-cycle), or recover
the waste heat from the boiler exhaust to generate electricity (bottoming-cycle).
4. Micro-CHP systems (sizes in the range of 3 to 20 kW) meant for individual
residential and small-scale applications.

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