Thermal Storage Using Metallic Phase Change Materials for Bus Heating—State of the Art of Electric Buses and Requirements for the Storage System

Kraft, Werner; Stahl, Veronika; Vetter, Peter

doi:10.3390/en13113023

Cited by 13 publications

(8 citation statements)

References 11 publications

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“…For a favored design option selected here, maximum systemic storage densities of 201 Wh/kg with a charging power of 6.4 kW were achieved by simultaneous low maximum heat losses of 76 W for a permitted exterior surface temperature of 60 • C. Comparing the thermal storage densities with those of battery powered PTC heaters operating in a range from 100 Wh/kg to 180 Wh/kg [15,36] for today's commercial Li-Ion systems, the vehicle-systemic and even cost potentials are obviously in spite of drawbacks regarding exergetic potentials. For proofing and confirming the storage concept, a test rig was erected focusing experimental investigations on the charging process and model validations.…”

Section: Discussionmentioning

confidence: 99%

“…Within the solid honeycomb wall (zone II), the radial transient heat balance is based on Equation (15):…”

Section: Effective Radiation Coefficientmentioning

confidence: 99%

“…So far, several studies have been performed for thermal storage systems based on phase change materials (PCM) for heat supply [14][15][16], for preheating of catalysts [17], for combustion engines [18] and for cooling applications [19]. New ways for thermal management concepts based on thermochemical energy storage systems (solid/gas reaction) are described in [20], offering an alternative heat and cold supply especially for fuel cell vehicles.…”

Section: Introductionmentioning

confidence: 99%

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Thermal Battery for Electric Vehicles: High-Temperature Heating System for Solid Media Based Thermal Energy Storages

Dreißigacker

2021

Applied Sciences

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Thermal energy storage systems open up high potentials for improvements in efficiency and flexibility for power plant and industrial applications. Transferring such technologies as basis for thermal management concepts in battery-electric vehicles allow alternative ways for heating the interior and avoid range limitations during cold seasons. The idea of such concepts is to generate heat electrically (power-to-heat) parallel of charging the battery, store it efficiently and discharge heat at a defined temperature level. The successful application of such concepts requires two central prerequisites: higher systemic storage densities compared to today’s battery-powered PTC heaters as well as high charging and discharging powers. A promising approach for both requirements is based on solids as thermal energy storage. These allow during discharging an efficient heat transfer to the gaseous heat transfer medium (air) due to a wide range of geometric configurations with high specific surfaces and during charging high storage densities due to use of ceramic materials suitable for high operating temperatures. However, for such concepts suitable heating systems with small dimensions are needed, allowing an efficient and homogeneous heat transfer to the solid with high charging powers and high heating temperatures. An appropriate technology for this purpose is based on resistance heating wires integrated inside the channel shaped solids. These promise high storage densities due to operating wire temperature of up to 1300 °C and an efficient heat transport via radiation. Such electrically heated storage systems have been known for a long time for stationary applications, e.g., domestic storage heaters, but are new for mobile applications. For evaluation such concepts with regard to systemic storage and power density as well as to identify preferred configurations extensive investigations are necessary. For this purpose, transient models for the relevant heat transport mechanisms and the whole storage system were created. In order to allow time-efficient simulations studies for such an electrical heated storage system, a novel correlation for the effective radiation coefficient based on the Fourier Number was derived. This coefficient includes radiation effects and thermal conduction resistances and enables through its dimensionless parameterization the investigation of the charging process for a wide range of geometrical configurations. Based on application-typical specifications and the derived Fourier based correlation, extensive variation studies regarding the storage system were performed and evaluated with respect to systemic storage densities, heating wire surface loads and dimensions. For a favored design option selected here, maximum systemic storage densities of 201 Wh/kg at maximum heating wire surface loads of 4.6 W/cm2 are achieved showing significant benefits compared to today’s battery powered PTC heaters. Additionally, for proofing and confirming the storage concept, a test rig was erected focusing experimental investigations on the charging process. For a first experimental setup-up including all relevant components, mean temperature-related deviations between the simulative and the experimental results of 4.1% were detected and storage temperatures of up to 870 °C were reached. The systematically performed results confirm the feasibility, high efficiency, thermodynamic synergies with geometric requirements during thermal discharging and the potential of the technology to reach higher systemic storage densities compared to current solutions.

show abstract

Section: Discussionmentioning

confidence: 99%

“…Within the solid honeycomb wall (zone II), the radial transient heat balance is based on Equation (15):…”

Section: Effective Radiation Coefficientmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Thermal Battery for Electric Vehicles: High-Temperature Heating System for Solid Media Based Thermal Energy Storages

Dreißigacker

2021

Applied Sciences

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“…These materials have different levels or kinds of properties. The use of metallic PCMs like other materials used for a similar purpose can transport heat away from a critical device meaning that they can buffer the temperature of a device during periods of transient high-power operation [80] . They then can store that heat using the latent heat of fusion.…”

Section: Metallics Used As Pcmsmentioning

confidence: 99%

Encapsulation methods for phase change materials – A critical review

Huang

Stonehouse

Abeykoon

2023

International Journal of Heat and Mass Transfer

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“…The study showed that the designed THS could increase the vehicle's range in winter conditions by up to 26.7% for the chosen driving scenario. An even higher potential is expected for vehicles with higher heating demand, like buses [11].…”

Section: Introductionmentioning

confidence: 99%

Simulative Investigation of Thermal Capacity Analysis Methods for Metallic Latent Thermal Energy Storage Systems

et al. 2021

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Latent heat storage systems are a promising technology for storing and providing thermal energy with low volume, mass and cost requirements, especially when operated at high temperatures. Metallic phase change materials are particularly advantageous for high thermal input and output, which is especially important for mobile applications. When designing a storage system, it is essential to have precise knowledge about the potential storage capacity. However, the system’s storage capacity is typically calculated from material properties determined at lab scale, although systemic boundary conditions can have a considerable influence. Systemic influences can result from thermal and reactive interfaces or from the storage design. In order to consider these influences, we propose three calorimetric procedures to thermally analyse high-temperature metallic latent energy storage systems at an application scale. We examined the procedures in a transient simulation environment, monitoring the storage capacity of the system. The procedure, based on adiabatic conditions, shows the least deviation from the simulation input parameters, but is limited to the heating process of the storage. Discharging the storage can be represented by isoperibolic conditions with controlled heat exchange. The precision of the procedures depends on the evaluation routine, the calibration routine, the heat extraction rate and the thermal inertia of the test bench.

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Thermal Storage Using Metallic Phase Change Materials for Bus Heating—State of the Art of Electric Buses and Requirements for the Storage System

Cited by 13 publications

References 11 publications

Thermal Battery for Electric Vehicles: High-Temperature Heating System for Solid Media Based Thermal Energy Storages

Thermal Battery for Electric Vehicles: High-Temperature Heating System for Solid Media Based Thermal Energy Storages

Encapsulation methods for phase change materials – A critical review

Simulative Investigation of Thermal Capacity Analysis Methods for Metallic Latent Thermal Energy Storage Systems

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