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Volumetric & Calorimetric Measurements in Adsorption
Volumetric & Calorimetric Measurements in Adsorption
Accurate design of adsorption chillers, heat pumps, atmospheric water harvesting, and desalination systems requires reliable equilibrium, kinetics, and heat of adsorption data for the adsorbent-adsorbate pair. Our lab has developed custom volumetric and calorimetric facilities to measure these properties directly. The core platform is a constant-volume variable-pressure (CVVP) adsorption system, integrated with a heat flux sensor that enables simultaneous measurements of adsorption uptake and the heat released during adsorption. The facility has also been extended with a Volumetric Large Temperature Jump (V-LTJ) system to investigate the adsorption and desorption kinetics. Together, these facilities provide a unified experimental platform for comprehensive adsorption characterization under both equilibrium and transient conditions. This in-house developed facility is unique, as both adsorption characetrization and in-situ calorimetric measurements can be carried out simultaneously.
The experimental setup is automated through a LabVIEW-based data acquisition and control system, which synchronizes pressure, temperature, and heat flux measurements throughout each experiment. Simultaneous measurements of uptake and heat of adsorption is used to evaluate isotherm equations and identify those that consistently predict both. This enables more reliable performance prediction of adsorption-based thermal systems.
The V-LTJ facility resolves transient adsorption and desorption behaviour, giving insight into the coupled heat and mass transfer processes within the adsorbent bed. These measurements guide the optimization of miniaturized adsorption heat exchanger geometry, including fin configurations, to improve heat and mass transfer performance. Future work aims to extend the facility to investigate higher-pressure adsorption systems and, where appropriate, chemisorption-based working pairs.
Numerical Studies in Adsorption for Thermal Applications
Numerical Studies in Adsorption for Thermal Applications
Adsorption-based thermal technologies have emerged as promising sustainable solutions for refrigeration, thermal energy storage, dehumidification, desalination, and atmospheric water harvesting by efficiently utilizing low-grade thermal energy from renewable and waste heat sources. Research in this area focuses on understanding and optimizing the coupled heat and mass transfer, fluid flow, adsorption kinetics, and thermodynamic processes governing adsorption systems. Advanced modeling techniques are employed to investigate adsorbent materials, porous media transport, heat exchanger configurations, operating conditions, and regeneration strategies, enabling the design of compact, high-performance, and energy-efficient thermal systems. State-of-the-art simulation platforms, including ANSYS Fluent, COMSOL Multiphysics, and the Engineering Equation Solver (EES), are utilized to perform computational fluid dynamics (CFD), multiphysics simulations, and thermodynamic analyses for evaluating system performance under realistic operating conditions. These studies provide valuable insights into transient adsorption–desorption behavior, transport mechanisms, and performance limitations that are often difficult to capture experimentally. The integration of realistic climatic conditions with engineering optimization further supports the development of reliable, region-specific technologies with enhanced cooling capacity, water productivity, and energy efficiency. By combining advanced computational modeling with engineering design and optimization, this research contributes to the development of next-generation adsorption systems for sustainable cooling, water harvesting, thermal energy storage, and renewable energy utilization.
s-CO2 Heat Transfer Measurements and Numerical studies
s-CO2 Heat Transfer Measurements and Numerical studies
Supercritical carbon dioxide (sCO2) is an attractive working fluid for next-generation thermal systems because of its high efficiency, and favorable transport properties. Its application spans trans-critical CO2 refrigeration systems, where gas coolers replace conventional condensers, closed-loop sCO2 Brayton power cycles for advanced energy conversion and few polygeneration applications. Accurate prediction of heat transfer and pressure drop under supercritical conditions remains challenging due the abrupt thermo-physical property variation in the vicinity of the pseudo-critical (or near critical) region.
This research integrates experimental investigation, numerical simulation, and correlation development to improve the prediction of sCO2 heat transfer in miniaturized channels such as sub millimeter channels (a few 100 microns). A dedicated laboratory-scale test facility has been developed to generate high-quality experimental data over a wide range of operating conditions. Complementary 3D CFD simulations are also performed using ANSYS Fluent, while 1D thermodynamic analyses are carried out in EES. Temperature and pressure-dependent thermo-physical properties are evaluated using the NIST REFPROP database to accurately capture the property variations of supercritical fluids.
The experimental and numerical datasets are employed to develop generalized correlations for the Nusselt number and friction factor. Unlike conventional correlations, the proposed formulations explicitly account for the influence of fluctuating thermo-physical properties, thereby improving prediction accuracy near the pseudo-critical region. The outcomes contribute to the design and optimization of compact heat exchangers such as printed circuit heat exchanger (PCHE) and support the broader deployment of high-efficiency refrigeration and power generation technologies.
Hybrid Vapor-Compression Adsorption Chiller
Hybrid Vapor-Compression Adsorption Chiller
Under preparation
NOVAQUA
NOVAQUA
Under preparation
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