Article
Thermodynamics
Hariharan Kallath, Foster Kwame Kholi, Qingye Jin, Man Yeong Ha, Sang Hu Park, Hyeon-jun Kim, Jason Chetwynd-Chatwin, June Kee Min
Summary: The aim of the study was to improve the aero-thermal performance of CCA heat exchangers by enhancing flow uniformity through the new high-pressure side manifolds. Computational Fluid Dynamic (CFD) simulations and regression analysis were used to design new manifolds with improved flow uniformity, resulting in significant enhancements in performance.
APPLIED THERMAL ENGINEERING
(2021)
Article
Thermodynamics
Sudhanshu Pandey, Hariharan Kallath, Ho Yeon Choi, Thierry Sibilli, June Kee Min, Jason Chetwynd-Chatwin, Man Yeong Ha
Summary: This study investigates the aerothermal performance of a CCA heat exchanger with flow nonuniformities. The results show that heat transfer rate increases when the flow nonuniformity is symmetric and decreases when the flow nonuniformity is asymmetric.
APPLIED THERMAL ENGINEERING
(2022)
Article
Thermodynamics
Mrinal Jagirdar, Poh Seng Lee, Johan T. Padding
Summary: This study introduces equations and calculation methods for internally cooled and heated desiccant-coated heat and mass exchangers (ICHDHMX) and demonstrates through simulations that ICHDHMX can operate efficiently at low regeneration temperatures, making it suitable for various conditions in warm and humid weather.
APPLIED THERMAL ENGINEERING
(2021)
Article
Energy & Fuels
Bruna Rodrigues Nunes, Michel Kepes Rodrigues, Luiz Alberto Oliveira Rocha, Matthieu Labat, Sylvie Lorente, Elizaldo Domingues dos Santos, Liercio Andre Isoldi, Cesare Biserni
Summary: Significant advancements have been made in developing earth-air heat exchanger models in the past few decades. The geometric evaluation of different arrangements showed that complex designs can increase thermal potential, while configurations with few curves are beneficial for reducing air pressure drop.
INTERNATIONAL JOURNAL OF ENERGY RESEARCH
(2021)
Article
Construction & Building Technology
Liang Shi, Ming Qu, Xiaobing Liu, Lingshi Wang, Mingkan Zhang
Summary: This paper focuses on the study of a novel dual-purpose underground thermal battery (DPUTB) system that integrates a dual-source heat pump with hybrid thermal storage. A simplified dynamic model for the DPUTB is developed and validated using experimental data. The results of a parametric study show that the thermal conductivity of the inner tank shell and the melting point of the phase change material are the two most influential factors on the performance of the DPUTB. Future research will incorporate the DPUTB model into a dual-source heat pump system to evaluate the overall performance of demand side management.
ENERGY AND BUILDINGS
(2022)
Article
Thermodynamics
Fatma Calili-Cankir, Mohammed S. Ismail, Derek B. Ingham, Kevin J. Hughes, Lin Ma, Mohamed Pourkashanian
Summary: Two mathematical models were built to explore the reasons affecting the performance of air-breathing and conventional polymer electrolyte fuel cells. A parametric study revealed that the conventional fuel cell outperforms the air-breathing fuel cell due to higher forced convection-related heat and mass transfer coefficients. The two types of fuel cell respond differently to changes in porosity and thickness of the gas diffusion layer, and the air-breathing fuel cell is more sensitive to membrane thickness.
Article
Thermodynamics
Jiuxin Ning, Xiaodong Wang, Yajing Sun, Chenggang Zheng, Shengwu Zhang, Xi Zhao, Changyong Liu, Wentao Yan
Summary: Three types of PFHX were manufactured using LPBF technology, with the PFHX with twisted fins showing superior thermal performance and the PFHX with improved rectangular fins demonstrating the best overall performance.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
Jinhui Liu, Mengmeng Ai
Summary: This paper focuses on the improvement of heat transfer efficiency of air cooled high voltage motor heat exchanger. A mathematical and physical model of the heat exchanger is established based on hydrodynamics and numerical heat transfer theory. The model is validated with experimental data and optimized to enhance the heat transfer capacity of the heat exchanger.
CASE STUDIES IN THERMAL ENGINEERING
(2022)
Article
Construction & Building Technology
Guichen Li, Zhihua Wang, Fenghao Wang, Yujia Zhang
Summary: A novel biomimetic honeycomb fractal heat exchanger is proposed for the gas cooler in transcritical CO2 heat pump system, which offers advantages of high heat transfer efficiency and compactness. Computational fluid dynamics method is used to investigate the conjugate heat transfer performance between supercritical CO2 and water in the novel gas cooler. The results show that the biomimetic honeycomb fractal heat exchanger outperforms the printed circuit heat exchanger in terms of heat transfer performance.
JOURNAL OF BUILDING ENGINEERING
(2022)
Review
Environmental Sciences
Syed Noman, Harinarayana Tirumalachetty, Muthu Manokar Athikesavan
Summary: This paper provides an extensive review on geothermal heating and cooling systems, focusing on Earth-Air Heat Exchangers (EAHE) and Ground Source Heat Pump (GSHP) systems. The study identifies that the thermal conductivity of soil and the water content in the ground have significant effects on system performance.
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
(2022)
Article
Energy & Fuels
Mohammad Hossein Bahmani, Ali Hakkaki-Fard
Summary: This study presents a novel hybrid analytical-numerical model for accurately and quickly predicting the long-term performance of horizontal ground heat exchangers (HGHE). By utilizing Duhamel's theorem, modified infinite line source method, and superposition principles, along with considering the thermal interference between adjacent pipes, the proposed model can predict the transient performance of linear HGHEs with various pipe arrangements. The results show that the proposed semi-analytical method is up to 50 times faster than the traditional computational fluid dynamics (CFD) approach.
Article
Thermodynamics
Sofiya Pracht, Julian Will, Steffen Kloeppel, Thomas Funke, Hans Quack, Christoph Haberstroh
Summary: This study developed an aluminium 3D printed heat exchanger with optimized fin geometry, which can improve performance in cryogenic applications. Suggestions for improving the heat exchanger geometry were made based on experimental and numerical simulation results.
Article
Thermodynamics
Lucas Lovis, Priscilla Tremain, Andrew Maddocks, Behdad Moghtaderi
Summary: Water scarcity is a significant issue, particularly in developing countries and remote locations. This study investigates the potential of desiccant coated heat exchangers as a sorption reactor for atmospheric water generation. The study found that the coating at the inlet and outlet regions of the channels were underutilised.
ENERGY CONVERSION AND MANAGEMENT
(2023)
Article
Thermodynamics
Reza Attarzadeh, Marc Rovira, Christophe Duwig
Summary: Triply Periodic Minimal Surfaces (TPMS) show promising thermophysical properties, making them suitable for the production of low-temperature waste heat recovery systems. The study conducted simulations to quantify the performance of a TPMS based heat exchanger and found an optimized lattice design providing the highest thermal performance. This research can help improve the fabrication of TPMS heat exchangers for recycling waste heat in low temperature thermal systems.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Agriculture, Multidisciplinary
Geordie Zapalac
Summary: This study presents a simulation to evaluate a novel cooling system for unventilated greenhouses. The system cools the greenhouse during the day by transferring heat from the greenhouse air into a water reservoir, and discharges the accumulated heat to the outside air through an air-to-air heat exchanger during the night and morning. The simulation predicts that the energy requirement of the proposed cooling system is 6.9 times less than that of an air-cooled chiller with a coefficient of performance of 4, assuming a minimum ambient temperature of 12 degrees C.
COMPUTERS AND ELECTRONICS IN AGRICULTURE
(2022)
Article
Thermodynamics
Ransisi Huang, Jiazhen Ling, Vikrant Aute
APPLIED THERMAL ENGINEERING
(2020)
Article
Thermodynamics
Rohit Dhumane, Jiazhen Ling, Vikrant Aute, Reinhard Radermacher
Summary: This study discusses an innovative personal cooling system RoCo, evaluates its performance with different refrigerant alternatives, develops dynamic models, and validates with Modelica.
APPLIED THERMAL ENGINEERING
(2021)
Article
Thermodynamics
Ransisi Huang, Vikrant Aute, Jiazhen Ling
Summary: The paper introduces a general representation and solution methodology for vapor compression systems to predict steady-state performance. The method uses tearing method to determine the most efficient component execution order and then solves equations using quasi-Newton method. The effectiveness of the method is verified through six test systems.
APPLIED THERMAL ENGINEERING
(2021)
Article
Thermodynamics
Rohit Dhumane, Tianyue Qiu, Jiazhen Ling, Vikrant Aute, Yunho Hwang, Reinhard Radermacher, Allen Chad Kirkwood, Jack Esformes
Summary: This study investigates the variation in the cyclic performance of air conditioning systems conforming with the latest rating standards, revealing that thermal inertia and measurement uncertainty are significant contributors to cyclic degradation coefficient (C-d) deviation. The validated Modelica model analyzes the thermal inertia of code testers, but not all deviations in C-d are resolved at this point. Simulation of measurement uncertainty using the Monte Carlo method shows it to be a critical factor in the C-d deviation. This study is expected to facilitate improved test procedures by addressing variations arising from differences in code tester designs at different laboratories.
INTERNATIONAL JOURNAL OF REFRIGERATION
(2021)
Article
Construction & Building Technology
Jiazhen Ling, Daniel A. Dalgo, Shengwei Zhu, Yiyuan Qiao, Lingzhe Wang, Vikrant Aute, Jelena Srebric, Jan Muehlbauer, Yunho Hwang, Reinhard Radermacher
Summary: Personal Conditioning Devices (PCD) create a microenvironment around users, better satisfying individual thermal comfort compared to central HVAC systems. The RoCo is a novel PCD that provides conditioned air for up to 8 hours without rejecting waste heat. Experimental tests and EnergyPlus simulations demonstrate the significant energy-saving potential of RoCo in centrally air-conditioned buildings.
ENERGY AND BUILDINGS
(2021)
Article
Thermodynamics
James Tancabel, Vikrant Aute, Ellery Klein, Cheng-Yi Lee, Yunho Hwang, Jiazhen Ling, Jan Muehlbauer, Reinhard Radermacher
Summary: This research presents a method for designing air-to-refrigerant heat exchangers using computational simulations and optimization. The designed heat exchangers have shape-optimized, non-round tubes that outperform current state-of-the-art designs without compromising structural integrity. The experimental validation shows good agreement between simulation and test results, highlighting the potential of this method to design next-generation heat exchangers with improved performance and reduced volume, weight, and environmental impact.
APPLIED THERMAL ENGINEERING
(2022)
Proceedings Paper
Energy & Fuels
Tanjebul Alam, Daniel Bacellar, Jiazhen Ling, Vikrant Aute
Summary: The study focuses on the numerical modeling of phase change material heat exchangers and the sensitivity to different parameters, particularly the thermo-physical properties of the phase change material. Through simulation experiments, it was found that inaccurate values of thermo-physical properties significantly impact the performance of PCMHX.
PROCEEDINGS OF ASME 2021 INTERNATIONAL MECHANICAL ENGINEERING CONGRESS AND EXPOSITION (IMECE2021), VOL 8B
(2021)
Proceedings Paper
Thermodynamics
Jangho Yang, Jan Muehlbauer, Daniel Bacellar, Jiazhen Ling, Vikrant Aute, Yunho Hwang
Summary: This paper describes a test facility built for testing various PCM-HX configurations and phase change temperatures that will serve to validate the performance of novel PCM-HX designs. Based on the measured data, the energy balance is analyzed, and its temperature distribution is presented, with the maximum deviation between the predicted stored energy and the energy stored calculated from experimental measurements being less than 5%.
13TH IIR CONFERENCE ON PHASE CHANGE MATERIALS AND SLURRIES FOR REFRIGERATION AND AIR CONDITIONING (PCM2021)
(2021)
Proceedings Paper
Thermodynamics
Daniel Bacellar, Tanjebul Alam, Jiazhen Ling, Vikrant Aute
Summary: This study investigates a single straight tube heat exchanger using PCM with a nominal melting temperature of 37 degrees Celsius, leveraging automated parametric CFD simulations. The reduced order models (ROM's) reproduce the CFD simulations accurately for designs from the training data set, but show less agreement for designs from cross-validation and test sets. ROM's solve simulations 500,000 times faster than CFD, but additional training designs may be needed for improved robustness.
PROCEEDINGS OF THE TWENTIETH INTERSOCIETY CONFERENCE ON THERMAL AND THERMOMECHANICAL PHENOMENA IN ELECTRONIC SYSTEMS (ITHERM 2021)
(2021)