Theseus-FE Applications Automotive
: Electromobility
Simulation of Electric Vehicle Thermal Management
전기 자동차의 범위제한은 열 관리(Thermal Management) 사안과 깊은 관련이 있습니다.
The range of battery electric vehicles (BEV) is directly proportional to their battery capacity. With the current technology of battery cells on average a range of 6.6 kilometers per 1 kWh of battery capacity is achieved.
In practice the range of a BEV depends on the climate and environmental conditions. A large portion of the battery's power must be used for regulating the temperature in the passenger cabin. Under unfavourable conditions this can lead to a range reduction of up to 40%. For example, during a cold winter day the loss heat of a conventional internal combustion engine is no longer available as a "free" source of energy for heating the cabin.
Thermal analyses of cabin climatization have always been highly important for the layout of HVAC systems in cars. BEVs call for an even more extensive analysis covering the energy balance of the entire thermal system of the car. This necessarily includes the batteries themselves since running within the optimal operating temperature range extends life time and maintains maximum possible capacity. Furthermore, the study has to cover all measures for reducing battery power invested in passenger comfort rather than for the pure purpose of powering the car.
THESEUS‑FE를 사용한 열분석(Thermal Analysis)은 전기자동차의 범위를 늘리는데 도움이 됩니다.
배터리 작동 온도 범위
The range of battery electric vehicles (BEV) is directly proportional to their battery capacity. With the current technology of battery cells on average a range of 6.6 kilometers per 1 kWh of battery capacity is achieved.
In practice the range of a BEV depends on the climate and environmental conditions. A large portion of the battery's power must be used for regulating the temperature in the passenger cabin. Under unfavourable conditions this can lead to a range reduction of up to 40%. For example, during a cold winter day the loss heat of a conventional internal combustion engine is no longer available as a "free" source of energy for heating the cabin.
Thermal analyses of cabin climatization have always been highly important for the layout of HVAC systems in cars. BEVs call for an even more extensive analysis covering the energy balance of the entire thermal system of the car. This necessarily includes the batteries themselves since running within the optimal operating temperature range extends life time and maintains maximum possible capacity. Furthermore, the study has to cover all measures for reducing battery power invested in passenger comfort rather than for the pure purpose of powering the car.
Intelligent Climatization을 통한 범위 최대화
All potential measures listed below can be tested and evaluated by simulations with THESEUS‑FE. Relying on simulations during the early stage of car development drastically reduces the costs for trying out some variations compared to real physical testing. Most importantly these virtual tests can be done even before any prototype of the car exists. The insight gained during this stage can save a lot of money before a wrong decision materializes in a real prototype.
Measures for intelligent, range increasing climatization concepts include:
improved insulation of the cabin
application of materials with low thermal capacity to reach the desired cabin temperature faster and with less energy investment
zonal climatization, especially if the driver is the only person in the cabin
increased recirculating air operation of the HVAC system
pre-conditioning using auxiliary heating systems
electrically heated window panes which is more efficient than heating them up by warm air
fuel-powered heating systems (e.g. ethanol range extender)
seat heating to quickly increase local comfort levels
infrared radiators and electrically heated surfaces to support classical HVAC systems
use of modern glass materials which limit the exchange of thermal energy by radiation through the windows to the visible spectrum (e.g. infrared reflecting windows)
use of ventilation systems during parking driven by solar panels
infrared-reflecting surface coatings
optional shadowing measures to reduce solar energy input into the cabin
Electric vehicles demand novel, economic climatization concepts
To cite an example, THESEUS‑FE allows for wavelength-dependent transmission and reflection properties of windows. Several variants of windows and coatings can be simulated with ease to rate their influence on the thermal budget of the car. Simulation results thus give immediate feedback about the effect of the HVAC systems power as well as the thermal comfort of passengers.
Case study
[인간의 Thermal Comfort 모델을 통한 폭스바겐 e-Golf Cabin의 Thermal Simulation]
Volkswagen e-Golf - 개별 구성요소 세분화를 보여주는 시뮬레이션 모델의 실제 모델 및 단면
As part of the publicly funded BMBF project, E-Komfort involved generating a highly detailed finite element model for simulating the climate control system of the passenger compartment of a Volkswagen e-Golf. A model originally used for crash simulations was used as a basis for developing a cabin model for interior climate control systems. Simulations were performed in an virtual environmental chamber under winter and summer load conditions relevant to vehicle design and range. This work also involved testing and calibrating special lamp models (for simulating sunlight in environmental chambers), and then using these models in the simulation.
자동차 객실의 환경적 열 영향(Environmental Thermal Influence)
The paper (available for download below) describes an initial validation study demonstrating a simulating technique capable of delivering realistic predictions of average and local cabin air temperatures. We illustrate how we extrapolated and calibrated a simplified cabin model (known as a rapid or generator model) from a highly detailed e-Golf simulation model. Doing so allowed us to reduce computing time from several days to a few seconds without compromising the quality of the simulated average temperature of the cabin air.
Using THESEUS‑FE simulations, we were able to demonstrate that employing zonal climate control concepts can massively reduce the amount of energy that the climate control system consumes. Energy can also be conserved through the use of infrared emitters, which were simulated using suitable models and assessed in terms of their impact on local thermal comfort values. Under winter load conditions, e-vehicle range is significantly limited by the amount of energy consumed by the climate control system. As such, heating or cooling passengers only where needed and/or only to a comfortable temperature makes more sense than heating/cooling the entire passenger compartment. Against this backdrop, our simulation also incorporated a thermophysiological model and used the concept of equivalent temperature as a basis for assessing local thermal comfort. The final portion of the paper provides a discussion of motivation and strategies for coupled cabin simulations - in this case coupling THESEUS‑FE and OpenFOAM - as well as the corresponding validation work.
객실 Climatization에 대한 전산 유체 역학 결과