Session: 04-01: Research for the Clean Energy Transition I

Paper Number: 130332

130332 - Optimal Operation of a District Heating System Using a PV-Assisted CO2 Heat Pump and Thermal Energy Storage 

Abstract: 

This work examines a combined component, fifth-generation district heating system (DHS) with an emphasis on CO₂ emission reduction and greater adaptability to diverse heat sources. There are two primary contributions resulting from this analysis. First, a mathematical framework is created to simulate a combined photovoltaic (PV)-assisted CO₂ water-source heat pump (WSHP) with a sensible thermal energy storage (TES) system to provide domestic hot water for a district of 32 apartments. The scheduling of the heat production, along with temperature control of both the charging water to the TES and the discharging water from the TES to the district, plays a vital role in optimizing the demand-side management strategies and overall integrated-system efficiency. Subsequently, this paper applies a mixed-integer nonlinear optimization approach to operating the system, employing a non-dominated sorting genetic algorithm (NSGAII). The multi-objective optimization is performed to find the optimal trade-off between minimizing operational cost and maximizing the coefficient of performance (COP) of the system. Simulation and optimization scenarios are executed based on a model predictive control structure over 48 hours across different seasons, using Miami as a case study. The optimal time-resolved charging profiles and outlet water temperature of the heat pump are extracted based on different criteria from the Pareto frontier. The key result of the optimization is compared with the simulation result derived from a conventional control strategy. The comparison of time-resolved results can be used to guide the future development of smart controllers for these applications.

Presenting Author: Laura Schaefer Rice University

Presenting Author Biography: Dr. Laura Schaefer is the Burton J. and Ann M. McMurtry Professor in the Department of Mechanical Engineering at Rice University. She received a B.S. in Mechanical Engineering (1995) and a B.A. in English (1995) from Rice University, and her M.S. (1997) and Ph.D. (2000) degrees in Mechanical Engineering from the Georgia Institute of Technology. She was formerly a faculty member in Mechanical Engineering at the University of Pittsburgh from 2000-2015, where she was Deputy Director of the Mascaro Center for Sustainable Innovation, and Associate Director of the Center for Energy. She is an ASME Fellow, and a past Chair of the Advanced Energy Systems Division of ASME.

Authors:

Shima Soleimani Rice University
Kashif Liaqat Rice University
Jörg Temming Flowserve Corporation
Heiner Kösters Flowserve Corporation
Laura Schaefer Rice University