@inproceedings{66007, abstract = {{The reduction of CO2-emissions in the chemical industry is essential to meet European climate targets. Particularly, the reliance on fossil fuels for process heat supply is a key factor for CO2-emissions. Electrically driven compression heat pumps are a promising option to reduce fossil fuel consumption by upgrading low-temperature waste heat to a higher temperature level, provided that low-carbon electricity is available. However, the integration of heat pumps into chemical utility systems remains a challenge due to economic constraints and the high complexity associated with site-wide heat integration and retrofit of existing structures. This work presents a mixed-integer linear programming (MILP) approach for the optimization of utility systems with integrated heat pumps. To address computational complexity, candidate utility temperature levels are pre-selected, and feasible heat pump coefficients of performance (COP) are precomputed. The framework is applied to both greenfield and retrofit scenarios for a synthetic case study consisting of 400 process streams. In the greenfield scenario, optimal utility temperature levels and heat pump integration configurations are identified. For the retrofit scenario, temperature levels of an existing utility system are modified to reduce total annual costs (TAC). Additionally, sensitivity analysis is conducted to assess the influence of key economic and environmental parameters. The presented case studies demonstrate short solution times, highlighting the suitability of the proposed framework for screening studies and systematic sensitivity analyses in early-stage design and retrofit applications.}}, author = {{Hochhaus, Thorben and Grünewald, Marcus and Riese, Julia}}, booktitle = {{Systems and Control Transactions}}, issn = {{2818-4734}}, publisher = {{PSE Press}}, title = {{{Optimization of Site-wide Heat-Integrated Utility Systems with Heat Pumps using MILP}}}, doi = {{10.69997/sct.152209}}, volume = {{6}}, year = {{2026}}, } @inproceedings{66008, abstract = {{Heat pumps offer the possibility of reducing CO2-emissions in the chemical industry. However, the integration of heat pumps, especially in non-continuous processes, faces several challenges. Energy storage facilitates a way to enhance heat integration by providing a continuous supply of heat flows. By doing so, the question arises as to whether this implementation should be applied to the process or to the utility level. At the process level, there is usually more freedom, as one is not bound by the existing temperature levels of the utility system, which are mostly difficult to retrofit. Therefore, this study presents an approach that generates heat integration concepts at the process level based on two different criteria. These criteria influence which process streams are grouped for a storage implementation and therefore influence the heat integration. The aim is to maintain the heat flows as continuous as possible by integrated heat storages. Finally, the possible heat integration concept is evaluated in terms of energy efficiency by a know method for continuous process streams, here the pinch analysis.}}, author = {{Wloch, Johannes and Grünewald, Marcus and Riese, Julia}}, booktitle = {{Systems and Control Transactions}}, issn = {{2818-4734}}, publisher = {{PSE Press}}, title = {{{Development of a methodology for heat pump-based heat integration in batch processes}}}, doi = {{10.69997/sct.140728}}, volume = {{6}}, year = {{2026}}, } @inproceedings{60494, abstract = {{Pillow-plate heat exchangers (PPHEs) represent a viable alternative to conventional shell-and-tube and plate heat exchangers. The waviness of their channels intensifies fluid mixing in the boundary layers and facilitates heat transfer. Applying secondary surface structuring can further enhance the overall thermo-hydraulic performance of PPHEs, thus increasing their competitiveness against conventional heat exchangers. In this work, streamlined secondary structures applied on the PPHE surface were studied numerically to explore their potential in enhancing near-wall fluid mixing. Computational fluid dynamics (CFD) simulations of single-phase turbulent flow in the inner PPHE channel were performed and pressure drop, heat transfer coefficients, and overall thermo-hydraulic efficiency were determined. The simulation results clearly demonstrate a favourable influence of secondary structuring on the heat transfer performance of PPHEs.}}, author = {{Afsahnoudeh, Reza and Riese, Julia and Kenig, Eugeny Y.}}, booktitle = {{Systems and Control Transactions}}, issn = {{2818-4734}}, publisher = {{PSE Press}}, title = {{{Thermo-Hydraulic Performance of Pillow-Plate Heat Exchangers with Streamlined Secondary Structures: A Numerical Analysis}}}, doi = {{10.69997/sct.178665}}, volume = {{4}}, year = {{2025}}, } @inproceedings{60493, abstract = {{Heat pumps play a crucial role in decarbonizing the chemical industry. The integration and sizing of heat pumps in chemical processes is a challenging task in multi-product chemical processes due to the fluctuating waste heat supply and heat demand. Integrating heat pumps may require a retrofit of the utility system. Mathematical optimization is a useful tool to tackle this challenge by enabling the analysis of correlation between relevant system parameters and equipment sizing. This study demonstrates the utilization of mathematical optimization and parameter studies for utility system equipment sizing addressing fluctuating heat supply and demand profiles.}}, author = {{Hochhaus, Thorben and Wloch, Johannes and Grünewald, Marcus and Riese, Julia}}, booktitle = {{Systems and Control Transactions}}, issn = {{2818-4734}}, publisher = {{PSE Press}}, title = {{{A Data-Driven Conceptual Approach to Heat Pump Sizing in Chemical Processes with Fluctuating Heat Supply and Demand}}}, doi = {{10.69997/sct.196662}}, volume = {{4}}, year = {{2025}}, }