Optimal Design Method for Absorption Heat Pump Cycles Based on Energy-Utilization Diagram

Year 2019, Volume: 22 Issue: 1, 9 - 17, 02.03.2019

Kosuke Seki , Hironori Hattori Yoshiharu Amano

https://doi.org/10.5541/ijot.499627

Cited By: 2

Abstract

Optimization
for energy systems is considered at three levels: synthesis (configuration),
design (component characteristics), and operation. This paper aims to evaluate
the system performance and margins for improvement of two absorption heat pump
systems, including an absorber heat exchanger (AHX) and a solution heat
exchanger (SHX), and perform their design/operation optimization efficiently
based on an energy-utilization diagram (EUD) for performance improvement. Before
optimization, exergy efficiency is higher in the SHX cycle, while the margin
for improvement is larger in the AHX cycle. The optimization attempts to reduce
exergy destruction in the components where dominant exergy destruction caused
by heat transfer occurs. In the absorber, the operating points are adjusted to
make the temperature slopes at the hot and cold sides coincide. The design
parameters in other components are adjusted to improve the heat transfer
performances. The distribution of exergy destruction of each component leads to
improve exergy efficiency. After these improvements, exergy efficiency is
higher in the AHX cycle. It is concluded that we could efficiently realize the
design/operation optimization of thermodynamic systems using an EUD, because the
diagram presents both exergy destruction and margin for improvement at the
components comprehensively, as well as the operating properties of working
fluids.

Keywords

Optimal design, absorption heat pump system, exergy analysis, energy-utilization diagram

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