Page 110 - Sustainable On-Site CHP Systems Design, Construction, and Operations

88 CHP B a s i c s

Prequalified
A packaged CHP system that is rigorously preengineered and preassembled should
operate as expected when shipped to a customer site. Prior to sale a prototype system
should be fully validated and module designs must address all key issues. Therefore,
rigorous field testing of packaged CHP systems must be undertaken to ensure that all
of the features and capacities listed in catalogues are demonstrated prior to sales release.
Only in this manner will the packaged CHP system value proposition be enhanced.
Specialized test facilities that provide electrical and thermal load banks are used to
validate a prototype packaged CHP system for
1. Steady-state performance guarantees both at a rating condition such as ISO or
4
5
ARI standards and for variations in the ambient temperature and pressure.
2. Environmental outputs, both regulated exhaust emissions and noise, at these
conditions.
3. Transient response to component or utility failures, and changes of the site
electrical or thermal demands.
4. Dual-mode transition and start-up.
5. Multifuel transition and the system transient response for each fuel, if applicable.
6. Robust control system that guarantees predicable, reliable, and safe operation
for all the above issues and interfaces with the site to ensure that all foreseeable
load demands are met.

To ensure that each assembled packaged system performs as the prototype, a series
of qualification tests may also be performed including verifying the design point elec-
trical output, thermal output, and CHP system efficiency. Since the concentration of
undesirable exhaust emissions are usually regulated, they should also be measured for
compliance with local environmental codes prior to shipment. All of these tests must
also verify the functionality of the system controls and data communication.

Benefits and Shortcomings of Packaged CHP Systems
A packaged CHP system containing the above intrinsic features has many values
beyond those sometimes afforded by a traditional custom engineered CHP system. In
particular, the packaged system can have
• Enhanced performance
• Lower adverse environmental impact
• Higher reliability
• Better economic value

Each of these benefits is expanded upon in subsequent paragraphs. The packaged
CHP system does present certain shortcomings, however. Because the packaged system
outputs are optimized, they are well defined and rather inflexible. That is, the packaged
CHP system provides great value for a limited range of combined electrical and thermal
output energy, but it is likely incapable or inefficient to operate at greatly different