Track: Fundamentals and Applications
Sponsor: 1.13 Optimization
Chair: Christopher R. Laughman, Ph.D., Member, Mitsubishi Electric Research Laboratories, Waltham, MAWhile optimization is often viewed as part of the design process for new systems, it can also provide significant value for improving existing systems. This session discusses the use of optimization techniques to improve existing systems, ranging in size from heat exchangers to buildings, to achieve higher performance without restarting the system design process from scratch.

1. Optimization of Small Diameter Tube-Fin Heat Exchangers to Enable Performance Improvements, Charge Reduction and Cost Savings
Daniel Bacellar, University of Maryland, College Park, MD
While small diameter (≤ mm) tube-fin heat exchangers have the potential to improve performance, successful designs must meet many criteria. Three case studies are presented to illustrate how optimization techniques can be used to design drop-in 5mm tube-fin condenser replacements for a domestic refrigerator, a packaged terminal air conditioner, and a window air conditioner that meet engineering and economic objectives. An optimization method is applied to heat exchanger simulation tools to evaluate the performance of heat exchanger simulations to identify optimal configurations that meet many objectives. Results indicate that these designs can significantly enhance energy-efficiency, reduce refrigerant charge, and reduce material consumption and cost.

2. Improving Heat Exchanger Circuitry by Using Derivative-Free Optimization
Christopher R. Laughman, Ph.D., Member, Mitsubishi Electric Research Laboratories, Waltham, MA
While the interconnections between the tubes of a heat exchanger can have a significant effect on its performance, this circuitry is difficult to design by hand because of the large number of possible designs and the nonlinear and discontinuous dependence of the performance on that circuitry. We formulate the circuitry design as a binary constrained optimization problem, and apply derivative-free optimization (DFO) algorithms. We apply a number of existing DFO algorithms to this problem, and demonstrate that they can find optimal or near-optimal circuitry designs for realistic coil sizes after a limited number of simulations.

3. Optimizing Mini-Split Air Conditioning Units Using Alternative Refrigerants
Bo Shen, Ph.D., Member, ORNL, Oak Ridge, TN
Developments in the Montreal Protocol include the development of a global consensus to phase-down the use of HFC refrigerants, as well as the continuing transition among developing countries to phase-out the use of HCFC and introduce HFC as potential intermediary solution. This presentation covers efforts to develop optimized system designs for mini-split AC units used in developing and high ambient countries using alternative lower global warming potential refrigerants. There are available candidate refrigerants that can be introduced during the current phase-out transition in order to eliminate a costly 2-step transition from HCFC to HFC and HFC to lower GWP solutions.

4. Operation Optimization of Buildings As Virtual Batteries for the Grid with High Penetrations of Renewables
Zheng O'Neill, Ph.D., P.E., Member, University of Alabama, Tuscaloosa, AL
One approach for realizing the potential for both building energy cost savings and the integration of renewable energy systems (RES) into the power grid involves the proactive integration of building operation into the power grid by optimizing the operation of energy sources with time-sensitive electricity price. The operation scheduling problem is formulated with the RES, electrochemical batteries as energy sources, and the building envelope as thermal energy storage, and is solved as a mixed integer programming problem. A case study using the AMPL platform shows that such energy storage technologies provide an effective way to connect energy supply resources and demands, and facilitate efficient building operations.

Presented: June 25, 2017, 11:00 AM-12:30 PM
Run Time: 90 min.

This is a zip file that consists of PowerPoint slides synchronized with the audio-recording of the speaker (recorded presentation), PDF files of the slides, and audio only (mp3) for each presentation.