Development of Methods for Optimal Control and Management of Solar Heat Supply Systems: A Numerical Analysis

Analysis of Thermal Behavior in Liquid-cooling Battery Systems for Electric Vehicles Exposed to Solar Irradiance

In this study, we report a three-dimensional thermal-fluid-coupled finite element model (FEM) for a lithium-ion-battery liquid-cooling system, explicitly incorporating solar irradiance as a boundary condition. The model is validated computationally and used to investigate the pack’s thermal behavior under solar exposure. Two designs of the cooling architecture, focusing on flow channel geometry and manifold configuration, are proposed to enhance thermal management. Numerical analysis shows that the designs significantly improve performance. At an ambient temperature of 35 ℃, the optimized design reduces the maximum and average volumetric temperatures by 40.91 and 48.64%, respectively, compared with a reference configuration. It also achieves a peak temperature reduction of 25.42 ℃ under 2C discharge. We conclude that solar heating can raise the casing temperature of a pack to 79 ℃, driving inward heat conduction, and that optimizing inlet geometry to shorten flow paths is effective in mitigating axial temperature gradients. Furthermore, we propose the present simulation methodology as a practical, time-efficient alternative to year-long outdoor aging tests for battery thermal and degradation evaluation, enabling accelerated testing with rationally selected environmental profiles.

Performance assessment of a transcritical CO₂ refrigeration system using MATLAB/Simulink: parametric analysis of operational control strategies

This study presents a dynamic modeling approach using MATLAB/Simscape™ and Simulink® to evaluate the performance of an R744 transcritical CO₂ vapor-compression refrigeration cycle equipped with an internal heat exchanger (IHX). Unlike structural design optimization including IHX sizing, this study focuses on maximizing efficiency through the optimization of operational parameters such as superheat and pressure settings. Simulation scenarios included transient evaluations using Seoul’s annual outdoor temperature profiles, a parametric study varying superheat from 3 °C to 15 °C at a constant 35 °C ambient temperature, and an analysis of varying high- and low-side operating pressures. Results indicate that rising ambient temperatures increase refrigerant mass flow and cooling capacity, but significantly decrease the coefficient of performance (COP) due to a disproportionate increase in compressor power consumption. While higher superheat prevents liquid carryover, it reduces overall efficiency. Additionally, the optimal hot-side pressure for maximizing COP was found to be 10–12 MPa. Ultimately, this study demonstrates that system efficiency can be enhanced by 15–20% through operational parameter tuning alone, without hardware modifications.

Energy Performance study of a Cooling supply system with an Lithium bromide absorption chillers using Geothermal heat

Objective. The aim of the study is to determine the boundary conditions for the efficient operation of a lithium bromide absorption refrigeration machine operating on geothermal water. Method . The study is based on thermodynamic analysis methods. Result . A mathematical model based on mass and energy conservation laws for the generator, condenser, evaporator, absorber, and solution heat exchanger is developed. The simulation covers geothermal water inlet temperatures from 70 to 110°C, with constant cooling water and chilled water parameters. The study investigates the impact of the heat source temperature on the generator load, cooling capacity, and the coefficient of performance (COP). The results indicate that raising the driving temperature from 70 to 110°C improves the COP from 0.52 to 0.81. A sharp decline in performance is observed below 75°C due to poor vapor generation conditions. Optimal flow rate ratios between the geothermal fluid and the chilled water are identified to maximize cooling output. Incorporating a solution heat exchanger enhances the COP by 40-45% compared to a basic cycle. Conclusion . The findings provide practical guidance for designing efficient geothermal cooling systems and selecting appropriate operational strategies.

On the development of sensible heat storage for concentrated solar power applications: Thermo-fluid management and materials

Stable Operation Strategy for Near-Zero Discharge Evaporation and Crystallization System of Coal Chemical Wastewater Based on Model Predictive Control (MPC)

With the increasing integration of intelligent sensing, industrial communication networks, and Electromagnetic Waves, Antennas and Propagation technologies in smart process industries, stable control of complex multivariable systems has become essential for reliable information acquisition and distributed decision-making. This study proposes a stable operation strategy for a near-zero discharge evaporation and crystallization system for coal chemical wastewater based on model predictive control (MPC). A discrete state-space model incorporating influent chemical oxygen demand, salt concentration disturbances, liquid level–concentration coupling, and steam network constraints is established to characterize the dynamic behavior of the process. A rolling optimization controller integrating feedforward compensation and quadratic programming is developed to coordinate feed flow, steam regulation, and circulation control under multiple operational constraints. Simulation and industrial validation demonstrate that the proposed strategy reduces liquid level overshoot by 82.4%, decreases steam consumption fluctuation by 66.1%, and maintains stable operation with a water reuse rate above 92.3% under severe disturbance conditions. The results confirm that the MPC-based framework significantly enhances disturbance rejection, robustness, and energy efficiency while providing an effective engineering solution for cyber–physical industrial systems. Furthermore, the proposed architecture offers valuable references for communication-enabled intelligent monitoring, distributed sensing, and industrial automation applications associated with Electromagnetic Waves, Antennas and Propagation technologies.

Energy Supply Characteristics and Economic Analysis of a Coupled Heat Pump–Solar System

: Targeting the diverse and highly seasonal loads of existing residential buildings, this study develops a hybrid “solar–air-source heat pump–shower wastewater heat recovery–stratified thermal storage–fan-coil” system, and proposes a temperature-difference-threshold-driven valve–pump coordinated control strategy enabling multi-mode operation. Cross-season typical-day experiments are conducted to quantify energy balance and efficiency. Results indicate that midday during the shoulder and winter seasons forms an overlapping high-efficiency window; the maximum solar contribution ratio reaches 31.17%, and piping heat loss rates are 24%–38%. The air-source heat pump achieves a Coefficient of Performance (COP) of 1.38–3.39; wastewater heat recovery under shower conditions yields an Energy Efficiency Ratio (EER) of approximately 2.8–3.1; fan-coil space heating exhibits an EER of about 8.69–9.34. In summer, coordinated “domestic hot water + space cooling” operation is attainable. Based on local electricity tariffs, the annually normalized energy savings are approximately 2.83 × 10 4 MJ, with a cost saving of about 6363 RMB; the initial investment is about 18,060 RMB, yielding a simple payback period of roughly 2.84 years. The findings demonstrate that multi-source hybrid heat pump systems offer strong seasonal adaptability and favorable economics in existing residential applications. Further improvements in off-peak integrated efficiency can be achieved by optimizing the TC temperature-difference thresholds, enhancing solar piping insulation, and reducing fan-coil hydronic resistance with improved pump matching. The study provides a reproducible technical pathway and empirical data to support the engineering deployment of hybrid heat sources in residential buildings.