Thermal Energy Exchange Research Articles

Predictive modelling of thermo-active tunnels in London Clay

Thermo-active structures are underground facilities that enable the exchange of thermal energy between the ground and the overlying buildings, thus providing renewable means of space heating and cooling. Although this technology is becoming increasingly popular, the behaviour of geotechnical structures under additional thermal loading is still not fully understood. This paper focuses on the use of underground tunnels as thermo-active structures and explains their behaviour through a series of finite-element analyses based on an existing case study of isothermal tunnels in London Clay. The bespoke finite-element code adopted – the Imperial College Finite Element Program (ICFEP) – is capable of simulating the fully coupled thermo-hydro-mechanical behaviour of porous materials. The complex coupled interactions between the tunnel and the surrounding soil are explored by comparing results from selected types of coupled and uncoupled simulations. It is demonstrated that: (a) the thermally induced deformation of the tunnel and the ground are more critical design aspects than the thermally induced forces in the tunnel lining, and (b) the modelling approach in terms of the type of analysis, as well as the assumed permeability of the tunnel lining, has a significant effect on the computed tunnel response and, hence, must be chosen carefully.

A multi-layer urban canopy meteorological model with trees (BEP-Tree): Street tree impacts on pedestrian-level climate

Vegetation alters urban climates via transpirational cooling; however, unlike shorter vegetation, trees additionally provide shade and shelter. Urban canopy models (UCMs) are coupled with mesoscale models for assessment of neighbourhood-scale climate, but their representation of urban trees is limited. We present BEP-Tree, a multi-layer UCM that integrates trees instead of using the ‘tile’ approach that characterizes most urban mesoscale modelling. BEP-Tree resolves the microclimate underneath trees where outdoor human thermal exposure occurs; these conditions are largely inaccessible to current mesoscale modelling and remote sensing approaches. Moreover, BEP-Tree allows trees to protrude above buildings, enabling assessment of low-rise neighbourhoods. The new model combines existing models, including detailed radiative and hydrodynamic models that assess built-tree interactions, and includes new parameterizations for impacts of tree foliage distribution. BEP-Tree is evaluated against unique datasets from three cities enabling assessment of modelled radiation, energy exchanges and road and air temperatures across the diurnal cycle. Urban trees redirect sensible heat into latent heat and reduce pedestrian-level solar radiation, wind, and temperatures during daytime. Thermal climate and energy exchanges are more sensitive to street tree density than height. Coupled with a mesoscale model, BEP-Tree enables assessment of urban forest-induced neighbourhood-to-city scale climate impacts during fair weather periods.

Thermal accommodation in nanoporous silica for vacuum insulation panels

The thermal accommodation coefficient is a measure for the quality of thermal energy exchange between gas molecules and a solid surface. It is an important parameter to describe heat flow in rarefied gases, for example, in aerospace or vacuum technology. As special application, it plays a decisive role for the thermal transport theory in silica filled vacuum insulation panels. So far, no values have been available for the material pairings of silica and various gases. For that reason, this paper presents thermal conductivity measurements under different gas-pressure conditions for precipitated and fumed silica in combination with the following gases: helium, air, argon, carbon dioxide (CO$_{2}$), sulfur dioxide (SO$_{2}$), krypton, and sulfur hexafluoride (SF$_{6}$). Additionally, a calculation method for determining thermal accommodation coefficients from the thermal conductivity curves in combination with the pore size distribution of silica determined by mercury intrusion porosimetry is introduced. The results are compared with existing models.

Thermal management of methanol reforming reactors for the portable production of hydrogen

Three-dimensional numerical simulations were performed to address the thermal management issues associated with the design of a methanol reforming microchannel reactor for the portable production of hydrogen. The design of the reactor was fundamentally related to the direct coupling of reforming and combustion reactions by performing them on opposite sides of dividing walls in a parallel flow configuration. Effective autothermal operation was achieved through a combination of microchannel reactor technology with heat exchange in a direction perpendicular to the reacting fluid flow. Computational fluid dynamics simulations and thermodynamic analysis were carried out to investigate the effect of various design parameters on the characteristics of the generation, consumption, and exchange of thermal energy within the system. The results indicated that the ability to control temperature and temperature uniformity is of great importance to the performance of the system. The degree of temperature uniformity favorably affects the autothermal operation of the reactor. Temperature uniformity of the reactor can be improved by controlling the rate of heat transfer through a variety of factors such as wall thermal conductivity, fluid velocities, and dimensions. High wall thermal conductivity would be greatly beneficial to the performance of the system and the temperature uniformity of the reactor.

Phonon heat transfer across a vacuum through quantum fluctuations.

Heat transfer in solids is typically conducted through either electrons or atomic vibrations known as phonons. In a vacuum, heat has long been thought to be transferred by radiation but not by phonons because of the lack of a medium1. Recent theory, however, has predicted that quantum fluctuations of electromagnetic fields could induce phonon coupling across a vacuum and thereby facilitate heat transfer2-4. Revealing this unique quantum effect experimentally would bring fundamental insights to quantum thermodynamics5 and practical implications to thermal management in nanometre-scale technologies6. Here we experimentally demonstrate heat transfer induced by quantum fluctuations between two objects separated by a vacuum gap. We use nanomechanical systems to realize strong phonon coupling through vacuum fluctuations, and observe the exchange of thermal energy between individual phonon modes. The experimental observation agrees well with our theoretical calculations and is unambiguously distinguished from other effects such as near-field radiation and electrostatic interaction. Our discoveryof phonon transport through quantum fluctuations represents a previously unknown mechanism of heat transfer in addition to the conventional conduction, convection and radiation. It paves the way for the exploitation of quantum vacuum in energy transport at the nanoscale.

Excess thermal energy and latent heat in nanocluster collisional growth.

Nanoclusters can form and grow by nanocluster-monomer collisions (condensation) and nanocluster-nanocluster collisions (coagulation). During growth, product nanoclusters have elevated thermal energies due to potential and thermal energy exchange following a collision. Even though nanocluster collisional heating may be significant and strongly size dependent, no prior theory describes this phenomenon for collisions of finite-size clusters. We derive a model to describe the excess thermal energy of collisional growth, defined as the kinetic energy increase in the product cluster, and latent heat of collisional growth, defined as the heat released to the background upon thermalization of the nonequilibrium cluster. Both quantities are composed of a temperature-independent term related to potential energy minimum differences and a size- and temperature-dependent term, which hinges upon heat capacity and energy partitioning. Example calculations using gold nanoclusters demonstrate that collisional heating can be important and strongly size dependent, particularly for reactive collisions involving nanoclusters composed of 14-20 atoms. Excessive latent heat release may have considerable implications in cluster formation and growth.

Un-stationary thermal analysis of the vertical ground heat exchanger within unsaturated soils

The efficiency of heat exchange in ground heat exchangers (GHE) in many projects decreases throughout their service life. Large temperature fluctuations were observed during the ground heat exchanger loading and during its natural cooling. This problem stems mainly from the influences of heating and humidity migration on the operation of the ground heat exchanger in unsaturated soil. To find the answer to the problem numerical model of a porous medium with multi-component fluid flow was applied. The mathematical description was expanded by additional streams describing the exchange of thermal energy within the backfill material and the structure of the porous model. Ground porosity was mapped geometrically and mathematically. The definition of total temperature was introduced. The results obtained from proposed model were compared with another model results which was based on solving only the classical heat exchange equation. The model was also verified through the measurement data read from 3 sensors installed at different depths of one borehole and at different time intervals. The parameters of the model result from local climatic conditions of Jabłonna near Warsaw. 24-hour operation of a single borehole was simulated numerically. The results of the model proposed by the author were of a greater convergence with the real data than those obtained for the classical heat exchange model. The critical point of the model was the selection of the coefficients describing the flow resistance of i-components in the porous medium and the particular terms of the total temperature adopted definition. The proposed model allows for a more accurate estimation of the available thermal power in the future and more accurate analysis of the degree of the effort of the structure in the context of its exploitation and the destruction time.

(Carl Wagner Memorial Award of the Electrochemical Society) Mathematical Modeling of Electrochemical Systems

In order to understand and accurately predict the behavior of electrochemical materials, devices, and systems, it is necessary to develop sophisticated mathematical models that consider, for example, transport processes, electrochemical phenomena, thermal and mechanical stresses, and structural changes during operation. This insight aids in the design and operation of electrochemical systems for a particular application. This talk will review some of the mathematical models that we have developed to predict the behavior of electrochemically active materials, fuel cells, electrolyzers, and batteries. In particularly, I will discuss the mathematical models we have developed to better understand the effect of volume change on the behavior of batteries. There are many models in the literature that can predict the electrochemical performance of batteries (e.g., voltage versus time) under a variety of operating (e.g., current) and design (e.g., electrode thickness) conditions. However, existing models do not consider how stresses can build up in the system as the expanding porous electrode is being constrained by the battery casing. Here I show predictions of the dimensional and porosity changes in a porous electrode caused by volume changes in the active material during intercalation (e.g., lithium into carbon or silicon). Porosity and dimensional changes in an electrode significantly affect the resistance of the battery during cycling. In addition, volume changes generate stresses in the electrode, which can lead to premature failure of the battery. Material conservation equations are coupled with the mechanical properties of the porous electrode to derive governing relations that link dimensional and porosity changes to stresses that occur during the intercalation process. The stress-strain relationships used in this model, which are needed to predict porosity and dimensional changes, have been established by examining the similarities between thermal rock expansion (e.g., the exchange of thermal energy with the rock) and electrode expansion due to intercalation.

Effects of Coulomb coupling on stopping power and a link to macroscopic transport

Molecular dynamics simulations are used to assess the influence of Coulomb coupling on the energy evolution of charged projectiles in the classical one-component plasma. The average projectile kinetic energy is found to decrease linearly with time when να/ωp ≲ 10−2, where να is the Coulomb collision frequency between the projectile and the medium, and ωp is the plasma frequency. Stopping power is obtained from the slope of this curve. In comparison to the weakly coupled limit, strong Coulomb coupling causes the magnitude of the dimensionless stopping power, (a/kBT)dE/dx, to increase, the Bragg peak to shift to several times the plasma thermal speed, and for the stopping power curve to broaden substantially. The rate of change of the total projectile kinetic energy averaged over many independent simulations is shown to consist of two measurable components: a component associated with a one-dimensional friction force and a thermal energy exchange rate. In the limit of a slow and massive projectile, these can be related to the macroscopic transport rates of self-diffusion and temperature relaxation in the plasma. Simulation results are compared with available theoretical models for stopping power, self-diffusion, and temperature relaxation.

A Transient Thermal Model for Flat-Plate Photovoltaic Systems and Its Experimental Validation

This paper describes a transient thermal model that accurately predicts the temperature of the open-rack mounted photovoltaic (PV) modules under varying atmospheric conditions. The PV module temperature is predicted by considering the thermal energy exchange between the PV module and its environment through the main heat transfer paths. The proposed thermal model has been validated by utilising data from the experiment: the temperature measurement of two identical PV modules operating in two different modes (open-circuit and full-load) was performed by means of three temperature sensors placed on the back surface of both PV modules. The model accuracy is 3 C of measured temperature values 100 % of the time under all conditions. The highest accuracy is obtained when the solar irradiance is subject to less fluctuation. The influence of the load level relative to the nominal power of the PV module on its temperature is hereby subject to consideration. DOI: 10.5755/j01.eie.25.2.23203

Measuring the coefficient of unit surface conductance of steel balls for frying without cooking oil by using dimensional analysis

Frying process is basically exchange of thermal energy through direct contact between a transferring heat medium and the food in high temperature. Cooking oil is the most commonly used as frying medium, but there is an alternative frying process without cooking oil by using sand and steel balls. Even though frying process is a very popular, theory of the frying process was long neglected and poorly understood. In frying process, coefficient of unit surface conductance is an important thermal property for analyzing heat transfer process. A common notation used for the coefficient is h and the unit is J/s.m2.C. Objective of this research was to measure the coefficient of unit surface conductance (h) by using dimensional analysis for constructing mathematical model. Laboratory experiments were conducted to find the h of steel balls with various diameters. An aluminum plate was used to simulate food being fried. A cylindrical frying machine was employed for frying process. The h value was determined based on dimensionless temperature ratio. The h values were then used to develop an empirical mathematical model using dimensional analysis. The developed mathematical model showed a good agreement with measurement results with average of errors was less than 10%.

Development of novel heat conduction interaction model for solid body thermal contact in CFD based particle flow simulations

Traditional computational fluid dynamics (CFD) simulations with resolved objects progressing through the fluid using a moving and deforming mesh require a fixed mesh topology. Though such simulations may more readily capture conditions where large gradients in the flow field exist, particularly high speed, compressible flow phenomena, the ability to directly model the conduction portion of the contact between particles or between particles and other solid bodies immersed in the fluid is thus restricted. A new method was devised to allow for the maintenance of the mesh topology while simulating the contact heat conduction between a discretized particle pair and between a discretized particle and a wall for the intended purpose of implementation of the technique within a computational fluid dynamics (CFD) based coupled particle–fluid flow model. The method is tested for a range of contact resistances (0–1 × 10−3 m2 K/W) and material thermal conductivity (1.60–162 W/m K) and specific heat (50.28–5028 J/kg-K) combinations with one object initially at 700 K and the other at 300 K. The temperature distributions across the mid-particle or mid-particle and wall line produced by the new method at a given time are compared to the results for a standard finite volume simulation of contacting bodies. The maximum difference in the local temperatures obtained is under 1%. Hence, the technique is a robust means of simulating the resolved heat conduction contact thermal energy exchange without connected computational elements, retaining the needed fluid gap space around the solid bodies. Future work will build upon this technique to include the convective and radiative modes of heat transfer before simulating moving and interacting particles in a fluid flow.

Enhancement of Heat Transfer in a Rouletted Copper Tube Employing Delta Winglet Twirled Type Insert

Heat transfer is a process or a system of thermal engineering that concerns the generation, use, conversion, transfer, internal or external molecular formation and exchange of thermal energy (heat) between physical systems. The research work has been experimented for the turbulent flow heat transfer in a tube having delta winglet twisted tape and then separately with water as working fluid. The test section consisted of a circular copper tube of 26.6 mm inner diameter, 900 mm length with five K-type thermocouples. Bulk temperature and pressure drops have been measured. Material of both the delta winglet twisted tape insert was stainless steel. Delta winglet twisted tape insert had a length of 795mm, width of 20mm, thickness of 2mm, pitch length of 120mm, twist ratio of 6 while wire coil insert had the same length as that of delta winglet twisted tape insert, wire diameter of 1mm, mean coil diameter of 22mm and pitch length of 30mm. Heat transfer rate, convective heat transfer coefficient, Nusselt’s number, friction factor and heat transfer efficiency have been calculated to analyze heat transfer performance of circular copper tube fitted with or without inserts in turbulent regimes (4000<Re<15000). Nusselt’s numbers for combination of delta winglet twisted tape and wire coil insert, wire coil insert only, delta winglet twisted tape insert only increased by 1.29 to 1.47, 1.19 to 1.34 and 1.10 to 1.15 times respectively than the plain tube. They increased by 17.95% to 27.61%, 15.97% to 20.20%, 8.90% to 12.02% and average of 21.65%, 17.44%, 8.95% respectively than the plain tube. Heat transfer rates also increased by 1.12 to 1.20, 1.06 to 1.09 and 1.03 to 1.05 times respectively compared to the plain tube. Heat transfer efficiencies increased by 1.36% to 1.62%, 1.24% to 1.47% and 1.14% to 1.34% respectively compared to the plain tube. Friction factors increased by 1.44 to 1.62, 1.34 to 1.43, 1.22 to 1.27 times respectively compared to the plain tube. The delta winglet twisted tape was the best arrangement for the enhancement of heat transfer rate as compared to the other inserts.

Enhancement of Heat Transfer in a Rouletted Copper Tube Employing Delta Winglet Twirled Type Insert

Heat transfer is a process or a system of thermal engineering that concerns the generation, use, conversion, transfer, internal or external molecular formation and exchange of thermal energy (heat) between physical systems. The research work has been experimented for the turbulent flow heat transfer in a tube having delta winglet twisted tape and then separately with water as working fluid. The test section consisted of a circular copper tube of 26.6 mm inner diameter, 900 mm length with five K-type thermocouples. Bulk temperature and pressure drops have been measured. Material of both the delta winglet twisted tape insert was stainless steel. Delta winglet twisted tape insert had a length of 795mm, width of 20mm, thickness of 2mm, pitch length of 120mm, twist ratio of 6 while wire coil insert had the same length as that of delta winglet twisted tape insert, wire diameter of 1mm, mean coil diameter of 22mm and pitch length of 30mm. Heat transfer rate, convective heat transfer coefficient, Nusselt’s number, friction factor and heat transfer efficiency have been calculated to analyze heat transfer performance of circular copper tube fitted with or without inserts in turbulent regimes (4000<Re<15000). Nusselt’s numbers for combination of delta winglet twisted tape and wire coil insert, wire coil insert only, delta winglet twisted tape insert only increased by 1.29 to 1.47, 1.19 to 1.34 and 1.10 to 1.15 times respectively than the plain tube. They increased by 17.95% to 27.61%, 15.97% to 20.20%, 8.90% to 12.02% and average of 21.65%, 17.44%, 8.95% respectively than the plain tube. Heat transfer rates also increased by 1.12 to 1.20, 1.06 to 1.09 and 1.03 to 1.05 times respectively compared to the plain tube. Heat transfer efficiencies increased by 1.36% to 1.62%, 1.24% to 1.47% and 1.14% to 1.34% respectively compared to the plain tube. Friction factors increased by 1.44 to 1.62, 1.34 to 1.43, 1.22 to 1.27 times respectively compared to the plain tube. The delta winglet twisted tape was the best arrangement for the enhancement of heat transfer rate as compared to the other inserts.

Effect of Length, Diameter, Chirality, Deformation, and Strain on Contact Thermal Conductance Between Single-Wall Carbon Nanotubes

Thermal energy transfer across physically interacting single-wall carbon nanotube (SWCNT) interconnects has been investigated using non-equilibrium molecular dynamics simulations. The role of various geometrical and structural (length, diameter, chirality) as well as external (deformation and strain) carbon nanotube (CNT) parameters has been explored to estimate total as well as area-normalized thermal conductance across cross-contact interconnects. It is shown that the CNT aspect ratio and degree of lateral as well as tensile deformation play a significant role in determining the extent of thermal energy exchange across CNT contacts, while CNT chirality has a negligible influence on thermal transport. Depending on the CNT diameter, aspect ratio, and degree of deformation at the contact interface, the thermal conductance values can vary significantly –by more than an order of magnitude for total conductance and a factor of 3 to 4 for area-normalized conductance. The observed trends are discussed from the perspective of modulation in number of low frequency out-of-plane (transverse, flexural, and radial) phonons that transmit thermal energy across the contact and govern the conductance across the interface. The established general dependencies for phonon governed thermal transport at CNT contacts are anticipated to help design and performance prediction of CNT-based flexible nanoelectronic devices, where CNT-CNT contact deformation and strain are routinely encountered during device operations.

Optical device for thermal effusivity estimation of liquids

We determined the thermal effusivity of liquids using an optical sensor based on the laser beam deflection technique, without directly heat the samples and thus minimally altering them. Applying a heat pulse in a thermo-optical slab we generate a unidimensional temperature distribution. This temperature distribution modifies the refractive index in the slab that finally causes the deflection of a laser beam that propagates perpendicularly to the direction of the heat propagation. The deflection of the laser beam depends on the interaction of the thermal energy with the sample at the slab interface. The exchange of thermal energy between the thermo-optical slab and the sample depends, on the thermal properties of both of them, being the thermal effusivity of our particular interest. Utilizing a theoretical model, we estimate the thermal effusivity of liquids using tridistilled-water and glycerine as reference.We present a simplified version of a past sensor proposal as well as the theoretical analysis of the sensor response. We obtain the thermal effusivity of tridistilled water and glycerine samples with a maximum error of 3%. Finally, we estimate the thermal effusivity of dissolutions of NaCl in tridistilled-water with maximum error of 7.3%.

Study on thermal energy storage properties of organic phase change material for waste heat recovery applications

The phase change materials (PCMs) are a class of materials which exhibit good phase transformations by undergoing cyclic freezing and melting processes through the influence of heat transfer. The increased research on materials has paved way for the development of heat storage materials with enhanced thermophysical properties suitable for waste heat recovery applications. Waste heat recovery is a practice that affords lower energy input through thermal energy exchange among sub-systems, whilecurbing pollution. This paper presents the experimental investigation on thermophysical properties and heat storage characteristics of an organic PCM for waste heat recovery applications. Experimental results reveal that, the organic PCM being utilized has exhibited congruent phase transition characteristics (∼60.8 °C), high latent heat capacity (∼164.28 kJ/kg), good thermal conductivity, and thermal stability as well. The test results suggest that, during the heating and cooling cycles, the rate at which the energy is being transferred between the PCM and the surrounding fluid strongly depends on the thermophysical properties and heat storage potential of the PCM. Heat transfer rates largely varied with the operating conditions, ranging from a few watts to over 1kW. These attributes enabled the PCM to be considered as a viable and energetic material for waste heat recovery applications.

On the impact of the wind speed on the outdoor human comfort: a sensitivity analysis

The energy demand of buildings and outdoor human comfort are key elements of a sustainable urban design. The wind speed has an enormous impact on thermal sensation, but the sensation itself is hard to quantify. The objective of this paper is to understand how the wind influences thermal energy exchanges, and to quantify its impact on outdoor thermal sensation. In order to do so, three outdoor comfort models were selected. Each thermal model was then calculated for the EPFL campus (Switzerland) by coupling the software tools CitySim and RayMan. In order to factor the importance of local meteorological data, two different sources of data are used: the software Meteonorm and recorded onsite data. Results obtained underline the impact of the wind speed on the thermal perception of pedestrians, describing the sensitivity of each of the thermal models, as well as the environmental characteristics.

CFD analysis of thermally induced thermodynamic losses in the reciprocating compression and expansion of real gases

The efficiency of expanders is of prime importance in determining the overall performance of a variety of thermodynamic power systems, with reciprocating-piston expanders favoured at intermediate-scales of application (typically 10–100 kW). Once the mechanical losses in reciprocating machines are minimized (e.g. through careful valve design and operation), losses due to the unsteady thermal-energy exchange between the working fluid and the solid walls of the containing device can become the dominant loss mechanism. In this work, gas-spring devices are investigated numerically in order to focus explicitly on the thermodynamic losses that arise due to this unsteady heat transfer. The specific aim of the study is to investigate the behaviour of real gases in gas springs and to compare this to that of ideal gases in order to attain a better understanding of the impact of real-gas effects on the thermally induced losses in reciprocating expanders and compressors. A CFD-model of a gas spring is developed in OpenFOAM. Three different fluid models are compared: (1) an ideal-gas model with constant thermodynamic and transport properties; (2) an ideal-gas model with temperature-dependent properties; and (3) a real-gas model using the Peng-Robinson equation-of-state with temperature and pressure-dependent properties. Results indicate that, for simple, mono- and diatomic gases, like helium or nitrogen, there is a negligible difference in the pressure and temperature oscillations over a cycle between the ideal and real-gas models. However, when considering heavier (organic) molecules, such as propane, the ideal-gas model tends to overestimate the pressure compared to the real-gas model, especially if the temperature and pressure dependency of the thermodynamic properties is not taken into account. In fact, the ideal-gas model predicts higher pressures by as much as 25% (compared to the real-gas model). Additionally, both ideal-gas models underestimate the thermally induced loss compared to the real-gas model for heavier gases. This discrepancy is most pronounced at rotational speeds where the losses are highest. The real-gas model predicts a peak loss of 8.9% of the compression work, while the ideal-gas model predicts a peak loss of 5.7%. These differences in the work loss are due to the fact that the gas behaves less ideally during expansion than during compression, with the compressibility factor being lower during compression. This behaviour cannot be captured with the ideal-gas law. It is concluded that real-gas effects must be taken into account in order to predict accurately the thermally induced loss mechanism when using heavy fluid molecules in such devices.

Linking scales in sea ice mechanics.

Mechanics plays a key role in the evolution of the sea ice cover through its control on drift, on momentum and thermal energy exchanges between the polar oceans and the atmosphere along cracks and faults, and on ice thickness distribution through opening and ridging processes. At the local scale, a significant variability of the mechanical strength is associated with the microstructural heterogeneity of saline ice, however characterized by a small correlation length, below the ice thickness scale. Conversely, the sea ice mechanical fields (velocity, strain and stress) are characterized by long-ranged (more than 1000 km) and long-lasting (approx. few months) correlations. The associated space and time scaling laws are the signature of the brittle character of sea ice mechanics, with deformation resulting from a multi-scale accumulation of episodic fracturing and faulting events. To translate the short-range-correlated disorder on strength into long-range-correlated mechanical fields, several key ingredients are identified: long-ranged elastic interactions, slow driving conditions, a slow viscous-like relaxation of elastic stresses and a restoring/healing mechanism. These ingredients constrained the development of a new continuum mechanics modelling framework for the sea ice cover, called Maxwell-elasto-brittle. Idealized simulations without advection demonstrate that this rheological framework reproduces the main characteristics of sea ice mechanics, including anisotropy, spatial localization and intermittency, as well as the associated scaling laws.This article is part of the themed issue 'Microdynamics of ice'.