554
CHAPTER 15
THERMAL SYSTEMS OPTIMIZATION
Reinhard Radermacher
University of Maryland
College Park, Maryland
1 INTRODUCTION
554
2 OPTIMIZATION TOOLBOX
554
2.1 System Evaluation
555
2.2 Optimization Drivers
559
3 METHODOLOGY
562
3.1 Case Studies
562
SYMBOLS
571
BIBLIOGRAPHY
571
1
INTRODUCTION
Thermal systems include all functional groups of equipment and working fluids that are
designed to manage temperature and humidity conditions inside various spaces or materials.
Thermal management systems provide comfort, establish and maintain conditions necessary
for the functionality of other equipment, or utilize the change of thermo-physical properties
of materials for energy conversion. Applications run from thermal management of electronic
systems (electronic cooling) to space conditioning and power generation.
Optimization is the systematic procedure that guides system designers in their choice
of processes and components such that all requirements for the system are balanced in the
best fashion possible. In most applications the designer has to balance several contradicting
demands, such as high efficiency and reliability versus low costs and emissions. To keep the
design time and associated costs as low as possible, it is essential to take all requirements
of the thermal system into account at the earliest possible design stage. Often a great amount
of time and costs can be saved if the design engineer has means to evaluate the approximate
costs of a design in the early stages of the development.
The optimization of thermal systems usually includes a mixture of technology decisions
and the optimization of specific properties of selected components. One example is the
decision between tube-fin and microchannel technology for an air-refrigerant heat exchanger
in the air-conditioning system of a commercial building and the subsequent optimization of
tube diameter /channel geometry and fin spacing. The system designer should find the least
expensive designs for each technology that provides the required performance, i