22 May 2008

THE MEASURED PERFORMANCE AND MODEL BASED PERFORMANCE ANALYSIS OF A 16 kW ABSORPTION CHILLER


A 16 kW steam driven double-effect water LiBr absorption chiller with parallel
solution configuration has been designed, manufactured, and installed for the Intelligent
Workplace at Carnegie Mellon University. This particular chiller is driven by saturated steam
at a pressure of 6 bar and is based on a 55% (by mass) LiBr/water solution. A steady-state
computational model for the chiller has been developed based on a set of scientific and
engineering principles including: material and energy balances, correlations describing the
heat and mass transfer, and the thermo-physical properties of the working fluids. Additional
instrumentations were installed in the chiller to make possible the calculation of heat and
mass transfer coefficients in the various sections of the chiller at different conditions. Overall
deviation between the measurements and the model simulation results are calculated based
on the statistical analysis procedure to evaluate the model accuracy. At design condition, the
overall deviation is about 5%. On the basis of the model analysis, the strategies to improve
the chiller performance at the partial load conditions have been devised and the model has
been validated to calculate chiller performance under various operating conditions.