Page 115 - Sustainable On-Site CHP Systems Design, Construction, and Operations

Packaged CHP Systems 93

20
CO 2 reduction for year (%) 15 5

10

0
Sys 1: E+H Sys 2: E+C Sys 3: E+H+C
FIGURE 5-3 Packaged CHP system with added functionality reduces greenhouse gas emissions
for seasonal thermal demands.

control technology. This results in the lowest pollutant per unit of input fuel. The limit-
ing case is a fuel cell prime mover which does not use a combustion process and pro-
duces practically zero concentrations of these emissions.
Further, regulators recognize that the effective metric is pollutant per unit of output
energy which can be represented as

Pollutant/output energy = (pollutant/input fuel × input fuel)/output energy
≅ combustion control technology/fuel utilization
Hence, the CHP system minimizes this pollution metric by both employing the best
pollution control technology (i.e., lower pollutant per unit input fuel) and achieving the
highest fuel utilization (i.e., using the lowest amount of fuel per unit output).
While greenhouse gas (GHG) and regulated pollutant benefits are realized by all
CHP systems, they can be maximized with a packaged CHP system because of the per-
formance and fuel utilization benefits described above. A packaged CHP system can also
be designed to yield lower waste material at an installation site because of its precisely
defined mechanical, electrical, and communication/control interfaces.

Higher Reliability
The higher reliability of a packaged CHP system derives primarily from the extensive
prototype validation testing and the assembled system qualification testing described
previously. The control system is validated both to achieve desired outputs and to limit
operation outside of safe component capabilities. Scheduled maintenance is often better
defined. The entire package assembly can be inspected to ensure mechanical and electrical
quality. In this manner, the packaged CHP system can be relied upon to deliver predict-
able performance capability and a low probability of premature equipment failure.

Better Economic Value
Economic value becomes a critical feature to be considered during the preengineering,
preassembly, and prequalification steps of a packaged CHP system development. In
addition to maximizing useful outputs, steps can be undertaken to help ensure duplication