Page 43 - Sustainable On-Site CHP Systems Design, Construction, and Operations

22 CHP B a s i c s

For example, an office building can be unoccupied in many cases more than 4000 hours per
year. Industrial facilities, on the other hand, can operate 8760 hours per year with fairly
constant electrical and thermal load. A good example is a nutritional manufacturing facility
that has simultaneous high thermal and electrical demand. Given the characteristics of
commercial facilities, a good understanding of the building loads is mandatory for efficient
selection and sizing of the BCHP system. This section provides a background information
on the applicability of BCHP to the commercial sector, and covers in detail such issues as
which fuel is typically used for BCHP application, which building types are good candi-
dates for BCHP, which climatic location is favorable for BCHP, and which are common
types and sizes of prime movers. Under all circumstances a more rigorous analysis (feasibil-
ity study) will be required for the determination of the most cost-effective BCHP for a par-
ticular application; Part 2 Chap. 8 covers feasibility study methods in more detail.
In general, the applicability of CHP to commercial and institutional facilities is
influenced by the following factors.
Prime Mover Fuel Type
Onsite Sycom Energy Corporation (Onsite 2000) utilized the Hagler and Bailly Inde-
pendent Power Database (HBI) to develop a profile of exiting cogeneration activity in
the commercial sector.
Pertinent consolidated total values across all sector/building types are shown in
Table 2-1. Since natural gas (NG) is the leading fuel in existing CHP installations and also
given the fact that technologies such as coal, wood, and waste heat are not as readily avail-
able (or feasible for commercial applications) or are environmentally restricted (such as oil),
it is safe to assume that NG will continue to dominate the commercial BCHP market.
A newer report prepared for the U.S. Department of Energy, Energy Information
Administration (Discovery Insights 2006) provides update of the CHP market status,
but since the newer report doesn’t provide detailed information on existing and potential
applications for CHP systems (hospitals, hotels, education, and so on), the information in
this chapter is based on Onsite Sycom Energy Corporation report (Onsite 2000).

Building Type (Sector) and Size
The applicability of BCHP is based on previous experience and future potential. This
section is based on Onsite Sycom Energy Corporation study (Onsite 2000) and includes
both existing BCHP installations and potential ones. Table 2-2 lists all the commercial
applications covered by Onsite Sycom Energy Corporation study (Onsite 2000).

Variable\Fuel Natural
Type Coal (%) Gas (%) Oil (%) Waste (%) Wood (%) Other (%) Total (%)
Number of 1.8 88.4 3.1 2.6 0.4 3.7 100.0
installations
Total power (MW) 8.9 72.0 2.2 13.3 0.9 2.7 100.0
Total heat 15.5 52.7 3.9 23.4 1.9 2.6 100.0
(10 Btu/h)
6

Source: Based on Onsite (2000).
TABLE 2.1 Fuel Use Distribution of Existing CHP Plants