Page 116 - Sustainable On-Site CHP Systems Design, Construction, and Operations

94 CHP B a s i c s

Skid
manufacturer
100
Control
valve
Electrical generators 75
Thermally Installed cost (%) 50
activated Skid Skid
device
Skid Skid
Miscellaneous hardware 25
0
Ducting hardware Customer Baseline Packaged CHP
site Fuel system hardware

FIGURE 5-4 Cost-benefi t of packaged CHP systems.

of minimal levels of fuel consumption, on-site installation time and labor, and mainte-
nance time and labor. Maximum output and minimal installation features help reduce
the first cost of the system by right sizing the components and equipment, while the
fuel and maintenance features can minimize operating cost. The importance of mini-
mizing on-site installation time cannot be overemphasized (Fig. 5-4). These costs can
represent a significant portion of a package CHP system overall cost because industry
recognized package CHP installation protocols are not yet fully standardized and local
labor rates can be high. Packaged system utilization can be extended through the proper
selection of the TAT device such as the use of an absorption chiller to permit seasonal
cooling or heating. Also capabilities such as dual mode operation to ensure power
delivery to critical devices or processes in the event of utility interruption can be
included to enhance the value of the packaged CHP system. In this case, the added
value is the avoided cost of lost revenue or work in process.
Together, all these features contribute to shorten the system payback, the time
period required for operational savings to offset initial costs (see Chap. 9). So whether
the customer is motivated by first cost or payback, the intrinsic features of a packaged
CHP system offers economic advantages over the traditional system.

Examples of Commercially Available Packaged CHP Systems
While custom engineered CHP systems have been common for many years, fully pack-
aged CHP systems—catalog systems that are preengineered, preassembled, and
prequalified prior to shipping to a customer site—are only presently available from a
limited number of manufacturers. The most common packaged CHP systems are E + H
systems that provide electricity and hot water. Packaged E + H + C systems that deliver
electricity, cooling (chilled water), and heating are much less common. The purpose of
this section is to provide characteristic performance of packaged CHP systems that
cover a range of sizes and prime mover technologies.

Power/Hot Water Systems
Most packaged CHP systems couple a prime mover and its companion generator with
a heat recovery unit to recover energy in the form of hot water (E + H). In some cases,
the heat recovery unit is an integral part of the prime mover design. For example, this