Page 369 - Sustainable On-Site CHP Systems Design, Construction, and Operations

342 Ca s e S t u d y 2

Key Results
The performance of the CHP system was carefully monitored during the initial months
of operation. A list of the key performance-related outcomes is shown in Table 20-4.
The project team identified a number of lessons learned that can help other engi-
neers in the industry. A list of key design-related outcomes is shown in Table 20-5.

Key Outcomes Remarks
1. Parasitic energy consumed by the Measured field data over a complete cooling
induced draft (ID) exhaust fan was not season showed that the ID fan was not a major
a significant issue, in terms of overall contributor to parasitic energy required to operate
system energy efficiency (This variable the system
speed ID fan is used to control exhaust
heat input to the absorption chiller)
2. Seasonal variations in energy The measured performance was very good, and
efficiency are to be expected, due to met the expectations defined at the beginning of the
varying thermal loads and equipment project. Monthly energy efficiencies of up to 80%
operating characteristics (based on LHV) were measured
3. System-level performance can be Steady-state performance can be measured quite
measured, and design intent verified adequately using standard control system quality
with proper field instrumentation instrumentation. More in-depth investigations might
require more elaborate instrumentation and data
collection equipment. Careful attention to sensor
calibration is also a key ingredient to success
4. Equipment-level performance can also The measured field data verified that each item
be measured, and design intent verified of major equipment in the CHP system was
with proper field instrumentation able to meet or exceed its design performance
specifications
5. Cleaning of turbine blades should Careful monitoring of blade condition will keep
be done according to the turbine the turbine operating at or near the desired
manufacturers’ recommendations performance
TABLE 20-4 Key Outcomes of the Performance Monitoring Work

Key Outcomes Remarks
1. Commissioning is a very important part As with any building- or plant-level energy
of a CHP installation project system
2. Guillotine dampers can be made to perform There is no need for specially designed
in an exhaust-driven chiller application (Note: guillotine dampers, although there may be
A guillotine damper is needed to protect the a need to carefully adjust the damper slide
absorption chiller from hot exhaust gases, mechanism during plant commissioning
when the chiller is not in operation)
3. Additional instrumentation (beyond that Additional sensors provide more information to
required for control purposes) is a valuable plant operators and energy managers, about
part of a CHP project equipment and system operating performance

TABLE 20-5 Key Design-Related Outcomes of the Project