Article
Energy & Fuels
Richard A. Beier, Stefano Morchio, Marco Fossa
Summary: A semi-analytical model has been developed for estimating design parameters of vertical boreholes and coupling them with heat pumps. The model is computationally efficient and capable of providing quick estimates of ground properties. It has been validated for coaxial boreholes and shows good accuracy with estimates within +/- 5% of the exact values.
Article
Thermodynamics
Richard A. Beier, Marco Fossa, Stefano Morchio
Summary: Ground source heat pumps are often coupled with vertical boreholes for heating and cooling buildings. Numerical simulations were conducted to study the impact of deeper boreholes on TRT analysis, showing wider ranges of undisturbed ground temperature and ground thermal conductivity. The study found that effective ground thermal conductivities varied within +/- 17% of the arithmetic average of the layer thermal conductivities.
APPLIED THERMAL ENGINEERING
(2021)
Article
Construction & Building Technology
Long Pei, Patrick Schalbart, Bruno Peuportier
Summary: This article introduces a new global model for evaluating the thermal response factor of vertical ground coupled heat pumps. The model combines the finite line source model, the two-dimensional heat conduction equation, and a newly developed three-points method. It enables fast and accurate calculation of the thermal response factor for different borehole configurations, with high efficiency and accuracy.
ENERGY AND BUILDINGS
(2022)
Article
Thermodynamics
Miguel Hermanns, Juan Manuel Rivero
Summary: The correct assessment of maximum and minimum temperatures in a geothermal HVAC system requires considering the thermal inertia of the grout and ground. The classical multipole method does not consider this, which led to the development of the enhanced multipole method. The present work mathematically proves the existence of term-by-term convergence, positioning the enhanced multipole method as an extension of the classical method for problems with relevant thermal inertia.
APPLIED THERMAL ENGINEERING
(2023)
Article
Thermodynamics
Juan Manuel Rivero, Miguel Hermanns
Summary: During the design of a new geothermal heat exchanger, special attention is paid to peak heating and cooling demands of the building to prevent material damages. The thermal response of the heat exchanger needs to consider thermal inertia of the heat carrying liquid, grout, and ground. By developing an enhanced multipole method, the model can accurately predict peak heating and cooling demands as well as slowly varying heat injection rates.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2021)
Article
Energy & Fuels
Miguel Hermanns, Juan Manuel Rivero
Summary: The study focuses on the symmetries and asymmetries in theoretical models for the unsteady thermal response of geothermal boreholes, providing mathematical proofs for the breakdown of some symmetries when considering additional factors such as thermal inertias of grout and surrounding ground. This research also identifies and proves other symmetries and asymmetries in the network of thermal resistances for which proofs are lacking in existing literature.
Article
Thermodynamics
Massimo Cimmino
Summary: This paper introduces an approximation method for finite line source (FLS) solution in simulating geothermal systems, using a weighted sum of exponentials approximation of the Gaussian Q-function to obtain an approximate solution of FLS. The new approximation is proven to be sufficiently accurate for simulations and results in significant gains in computational speed. In one case, the computational time for 1000 evaluations of FLS solution was reduced from 3.52 seconds to 20 milliseconds.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2021)
Article
Thermodynamics
Javier Rico, Miguel Hermanns
Summary: In this study, a new theoretical model for the thermal interaction of geothermal boreholes with aquifers is developed using matched asymptotic expansion techniques. The new model improves the accuracy by an order of magnitude compared to the state of the art, allowing for the assessment of the theoretical and conceptual merits and limits.
APPLIED THERMAL ENGINEERING
(2024)
Article
Green & Sustainable Science & Technology
Eero Hirvijoki, Janne Hirvonen
Summary: This paper explores the use of intermediate-to-deep coaxial geothermal boreholes for seasonal storage of district heat. The idea is to extract heat from bedrock, creating a temperature pothole that can be filled and used for thermal storage. Two scenarios are studied: maximizing the capacity factor of the district heating network and using intermittent wind power as a heat source. Simulation results show that with proper sizing and system power rating, the borehole can efficiently meet the heat demand.
Article
Construction & Building Technology
Yu Mingzhi, Lu Wei, Zhang Fangfang, Zhang Wenke, Cui Ping, Fang Zhaohong
Summary: This study presents a novel simple model for simulating the heat transfer of mid-deep buried U-bend pipe ground heat exchangers. The model showed that heat extraction capacity increased with the increase of ground thermal conductivity, ground volumetric heat capacity, buried pipe depth, and horizontal pipe length. The study also found that the heat extraction capacity of MBUGHE decreased significantly in the initial years, but gradually stabilized after 15 years of operation.
ENERGY AND BUILDINGS
(2021)
Article
Thermodynamics
Maria Letizia Fasci, Alberto Lazzarotto, Jose Acuna, Joachim Claesson
Summary: This paper proposes a method to calculate the thermal influence between neighboring independent boreholes based on the FLS model, emphasizing the importance of considering thermal influence and accurate estimation of ground thermal conductivity for simulation results.
APPLIED THERMAL ENGINEERING
(2021)
Article
Thermodynamics
M. Soltani, Pooya Farzanehkhameneh, Farshad Moradi Kashkooli, Armughan Al-Haq, Jatin Nathwani
Summary: The study optimized parameters of geothermal heat pump (GHP) system using genetic algorithm, reducing installation costs and improving energy efficiency over a ten-year simulation. Ethylene glycol was identified as the preferred circulating fluid for significant energy consumption reduction.
ENERGY CONVERSION AND MANAGEMENT
(2021)
Article
Thermodynamics
Antash Najib, Angelo Zarrella, Vinod Narayanan
Summary: This paper introduces a new approach to calculate the transfer functions for large diameter, shallow bore helical Ground Heat Exchangers using mean fluid temperature. The proposed method shows promising results in estimating the performance of Helical GHEs by analyzing the mean fluid temperature for different mass flowrates. The study provides mathematical formulations and a simplified resistance-based model for calculating the g-functions, demonstrating the effectiveness of the approach in predicting the thermal performance of the systems.
APPLIED THERMAL ENGINEERING
(2022)
Article
Green & Sustainable Science & Technology
Teresa Magraner, Alvaro Montero, Antonio Cazorla-Marin, Carla Montagud-Montalva, Julio Martos
Summary: Conventional models overestimate the effective thermal conductivity in the presence of groundwater during thermal response tests. A new model, which accurately estimates the thermal conductivity unaffected by underground flow, was developed and tested in borehole experiments, showing a significant improvement in accuracy compared to traditional models.
Article
Energy & Fuels
Zhengguang Liu, Gaoyang Hou, Hessam Taherian
Summary: This study explores the application of CuO/Al2O3 particles mixed with propylene glycol/water as a heat transfer medium in ground source heat pumps, aiming to improve heat efficiency and performance by studying different pipe types and NF concentrations. Results indicate that certain combinations can significantly increase outlet temperature and achieve higher COP values.
INTERNATIONAL JOURNAL OF ENERGY RESEARCH
(2022)
Article
Green & Sustainable Science & Technology
Massimo Cimmino
Article
Construction & Building Technology
Massimo Cimmino, Parham Eslami-Nejad
ENERGY AND BUILDINGS
(2017)
Article
Thermodynamics
Massimo Cimmino, Bantwal Rabi Baliga
NUMERICAL HEAT TRANSFER PART B-FUNDAMENTALS
(2017)
Article
Construction & Building Technology
Massimo Cimmino
JOURNAL OF BUILDING PERFORMANCE SIMULATION
(2018)
Article
Construction & Building Technology
Massimo Cimmino
JOURNAL OF BUILDING PERFORMANCE SIMULATION
(2018)
Article
Thermodynamics
Alex Laferriere, Massimo Cimmino
SCIENCE AND TECHNOLOGY FOR THE BUILT ENVIRONMENT
(2019)
Article
Thermodynamics
Massimo Cimmino
SCIENCE AND TECHNOLOGY FOR THE BUILT ENVIRONMENT
(2019)
Article
Thermodynamics
Massimo Cimmino, Bantwal R. (Rabi) Baliga
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2019)
Article
Energy & Fuels
Alex Laferriere, Massimo Cimmino, Damien Picard, Lieve Helsen
Article
Thermodynamics
P. Eslami-Nejad, A. Nguyen, M. Cimmino, A. Bastani, M. Badache
INTERNATIONAL JOURNAL OF REFRIGERATION
(2020)
Article
Thermodynamics
P. Eslami-Nejad, M. Cimmino, A. Nguyen, M. Badache, A. Bastani
INTERNATIONAL JOURNAL OF REFRIGERATION
(2020)
Article
Energy & Fuels
Iago Cupeiro Figueroa, Massimo Cimmino, Lieve Helsen
Article
Thermodynamics
Carlos Prieto, Massimo Cimmino
SCIENCE AND TECHNOLOGY FOR THE BUILT ENVIRONMENT
(2020)
Article
Construction & Building Technology
Carlos Prieto, Massimo Cimmino
Summary: The new method presented in the study extends the FLS solution and utilizes equivalent boreholes and hierarchical agglomerative clustering to accurately evaluate thermal interactions between groups of vertical geothermal boreholes, significantly reducing calculation times and providing accurate results even for large borefields.
JOURNAL OF BUILDING PERFORMANCE SIMULATION
(2021)
Article
Construction & Building Technology
Iago Cupeiro Figueroa, Massimo Cimmino, Jan Drgona, Lieve Helsen
Summary: This paper evaluates the performance of state observers in estimating borefield load history for accurate fluid predictions. Results show that both Time-Varying Kalman Filter (TVKF) and Moving Horizon Estimator (MHE) provide predictions with low errors, with MHE outperforming TVKF in certain aspects at the expense of more computational time.
JOURNAL OF BUILDING PERFORMANCE SIMULATION
(2021)
Article
Thermodynamics
Mahsa Taghavi, Swapnil Sharma, Vemuri Balakotaiah
Summary: This study investigates the natural convection effects in the insulation layers of spherical storage tanks and their impact on the tanks' performance. The permeability and Rayleigh number of the insulation material are considered as key factors. The results show that as the Rayleigh number increases, new convective cells emerge and cause the cold boundary to approach the external hot boundary. In the case of large temperature differences, multiple solutions may coexist.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Jinyang Xu, Fangjun Hong, Chaoyang Zhang
Summary: This study introduces a self-induced jet impingement device for enhancing pool boiling performance in high power electronic cooling. Through visualization and parametric investigations, the effects of this device on pool boiling performance are studied, revealing the promotion of additional liquid supply and vapor exhausting. The flow rate of the liquid jet is found to positively impact boiling performance.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Wenchao Ke, Yuan Liu, Fissha Biruke Teshome, Zhi Zeng
Summary: Underwater wet laser welding (UWLW) is a promising and labor-saving repair technique. A thermal multi-phase flow model was developed to study the heat transfer, fluid dynamics, and phase transitions during UWLW. The results show that UWLW creates a water keyhole, making the welding environment similar to in air laser welding.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Xingrong Lian, Lin Tian, Zengyao Li, Xinpeng Zhao
Summary: This study investigates the heat transfer mechanisms in natural fiber-derived porous structures and finds that thermal radiation has a significant impact on the thermal conductivity in low-density regions, while natural convection rarely occurs. Insulation materials derived from micron-sized natural fibers can achieve minimum thermal conductivity at specific densities. Strategies to lower the thermal conductivity include increasing porosity and incorporating nanoscale pores using nanosize fibers.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Yasir A. Malik, Kilian Koebschall, Stephan Bansmer, Cameron Tropea, Jeanette Hussong, Philippe Villedieu
Summary: Ice crystal icing is a significant hazard in aviation, and accurate modeling of sticking efficiency is essential. In this study, icing wind tunnel experiments were conducted to quantify the volumetric liquid water fraction, sticking efficiency, and maximum thickness of ice layers. Two measurement techniques, calorimetry and capacitive measurements, were used to measure the liquid water content and distribution in the ice layers. The experiments showed that increasing wet bulb temperatures and substrate heat flux significantly increased sticking efficiency and maximum ice layer thickness.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Jinqi Hu, Tongtong Geng, Kun Wang, Yuanhong Fan, Chunhua Min, Hsien Chin Su
Summary: This study experimentally examined the heat dissipation of vibrating fans and demonstrated its inherent mechanism through numerical simulation. The results showed that the flow fields induced by the vibrating blades exhibited pulsating features and formed large-scale and small-scale vortical structures, significantly improving heat dissipation. The study also identified the impacts of different blade structures and developed a trapezoidal-folding blade, which effectively reduced the maximum temperature of the heat source and alleviated high-temperature failure crisis.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Dan-Dan Su, Xiao-Bin Li, Hong-Na Zhang, Feng-Chen Li
Summary: The boiling heat transfer of low-boiling-point working fluid is a common heat dissipation technology in electronic equipment cooling. This study analyzed the interfacial boiling behavior of R134a under different conditions and found that factors such as the initial thickness of the liquid film, solid-liquid interaction force, and initial temperature significantly affect the boiling mode and thermal resistance.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Jinyi Wu, Dongke Sun, Wei Chen, Zhenhua Chai
Summary: A unified lattice Boltzmann-phase field scheme is proposed to simulate dendrite growth of binary alloys in the presence of melt convection. The effects of various factors on the growth are investigated numerically, and the model is validated through comparisons and examinations.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Shaokun Ge, Ya Ni, Fubao Zhou, Wangzhaonan Shen, Jia Li, Fengqi Guo, Bobo Shi
Summary: This study investigated the temperature distribution of main cables in a suspension bridge during fire scenarios and proposed a prediction model for the maximum temperature of cables in different lane fires. The results showed that vehicle fires in the emergency lane posed a greater thermal threat to the cables.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Shuang-Ying Wu, Shi-Yao Zhou, Lan Xiao, Jia Luo
Summary: This paper investigates the two-phase flow and heat transfer characteristics of low-velocity jet impacting on a cylindrical surface. The study reveals that the heat transfer regimes are non-phase transition and nucleate boiling with the increase of heat transfer rate. The effects of jet impact height and outlet velocity on local surface temperatures are pronounced at the non-phase transition stage. The growth rates of heat transfer rate and liquid loss rate increase significantly from the non-phase transition to nucleate boiling stage.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Emad Hasani Malekshah, Wlodzimierz Wlodzimierz, Miros law Majkut
Summary: Cavitation has significant practical importance and can be controlled by air injection. This study investigates the natural to ventilated cavitation process around a hydrofoil through numerical and experimental methods. The results show that the location and rate of air injection have a meaningful impact on the characteristics of cavitation.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Feriel Yahiat, Pascale Bouvier, Antoine Beauvillier, Serge Russeil, Christophe Andre, Daniel Bougeard
Summary: This study explores the enhancement of mixing performance in laminar flow equipment by investigating the generation of chaotic advection using wall deformations in annular geometries. The findings demonstrate that the combined geometry can achieve perfect mixing at various Reynolds numbers.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Hui He, Ning Lyu, Caihua Liang, Feng Wang, Xiaosong Zhang
Summary: This study investigates the condensation, frosting, and defrosting processes on superhydrophobic surfaces with millimeter-scale structures. The results reveal that the structures can influence the growth and removal of frost crystals, with the bottom grooves creating a frost-free zone and conical edges promoting higher frost crystal heights. Two effective methods for defrosting are observed: hand-lifting the groove and airfoil retraction contraction on protruding structures. This research provides valuable insights into frost formation and defrosting on millimeter-structured superhydrophobic surfaces, with potential applications in anti-frost engineering.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Thiwanka Arepolage, Christophe Verdy, Thibaut Sylvestre, Aymeric Leray, Sebastien Euphrasie
Summary: This study developed two thermal concentrators, one with a 2D design of uniform thickness and another with a 3D design, using the coordinate transformation technique and metamaterials. By structuring the thermal conductor, the desired local density-heat capacity product and anisotropic thermal conductivities were achieved. The homogenized thermal conductivities were obtained from finite element simulations and cylindrical symmetry consideration. A 3D concentrator was fabricated using 3D metal printing and characterized using a thermal camera. Compared to devices that solely consider anisotropic conductivities, the time evolution characteristics of the metadevice designed with coordinate transformation were closer to those of an ideal concentrator.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)
Article
Thermodynamics
Liangyuan Cheng, Qingyang Wang, Jinliang Xu
Summary: In this study, we investigated the supercritical heat transfer of CO2 in a horizontal tube with a diameter of 10.0 mm, covering a wide range of pressures, mass fluxes, and heat fluxes. The study revealed a non-monotonic increase in wall temperatures along the flow direction and observed both positive and negative wall temperature differences between the bottom and top tube. The findings were explained by the thermal conduction in the solid wall interacting with the stratified-wavy flow in the tube.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2024)