Proposed Test Methodology and Performance Rating Standard for Residential Fuel Cell Systems.
Proposed Test Methodology and Performance Rating
Standard for Residential Fuel Cell Systems.
(557 K)
Davis, M. W.; Ellis, M. W.; Dougherty, B. P.
NISTIR 7131; 85 p. June 2006.
Keywords:
fuel cells; test methods; classifications; equipment;
computation; data analysis; systems performance;
standards; energy systems; climate
Abstract:
A test method and rating standard is proposed for
residential fuel cell systems (RFCSs). The proposed
approach extends previously developed test procedures
for fuel cells by establishing specific test methods and
calculation procedures that are applicable to
residential fuel cell systems. These methods and
procedures provide the end user with metrics that can be
used to evaluate the merit of a RFCS in a particular
application. In the proposed standard, RFCSs are
classified into four types: Type I - Grid independent,
electrical load following; Type II - Grid
interconnected, constant power; Type III - Grid
interconnected, thermal load following; and Type IV -
Grid interconnected, water heating. Test procedures are
described that yield simplified models for the
performance of each system based on appropriate load
characteristics and ambient conditions. For Type I
systems, the steady fuel use, thermal energy output, and
water use are expressed as functions of the electrical
part-load ratio and the ambient temperature. In
addition, the thermal energy output, electrical output,
fuel use, and water use (for RFCS humidification)
associated with a hot water simulated use test are
evaluated as functions of electrical part-load ratio and
ambient temperature. Transient electrical load factors
are measured and applied to the thermal energy output
and the fuel consumption to incorporate the system's
performance under transient electrical loads. For Type
II systems, electrical power remains constant and the
steady fuel use, thermal energy output, and water use
are expressed as functions of ambient temperature. In
addition, the thermal energy output, electrical output,
fuel use, and water use (for RFCS humidification)
associated with a hot water simulated use test are
evaluated at rated power and specific values of ambient
temperature. For Type III systems, the system output
follows the thermal load and the steady fuel use,
electrical output, and water use are expressed as
functions of thermal part-load ratio and ambient
temperature. In addition, the electrical output, fuel
use, and water use (for RFCS humidification) associated
with a hot water simulated use test are evaluated at
specific values of ambient temperature. For Type IV
systems, the system operates to meet the hot water
requirement and the thermal energy output, electrical
output, fuel use, and water use (for RFCS
humidification) associated with a hot water simulated
use test are evaluated at specific values of ambient
temperature. For each system type, steady and simulated
use models are combined to predict the performance of
the system in response to typical residential electrical
and thermal loads for various representative climates.
For units that draw ventilation air from the indoors,
the performance is corrected to account for the energy
required to condition outdoor air to replace the
ventilation air. The annual performance is expressed in
terms of the impact on the end user's net electricity
use (or generation), fuel use, and water use.
Building and Fire Research Laboratory
National Institute of Standards and Technology
Gaithersburg, MD 20899