THESEUS‑FE is applied world-wide to solve a variety of engineering problems.
Historically, THESEUS‑FE was heavily used for thermal management analysis of various vehicle types,
including cars, busses, trains and aircrafts.
THESEUS‑FE is the right choice of simulation tool when the focus is on predicting thermal comfort of passengers or building occupants.
Nowadays, the application domain of THESEUS‑FE has expanded significantly. New features are regularly introduced to support specialized simulations in novel fields. As an example we can present the special components in the THESEUS‑FE portfolio for the simulation of automotive paint shop processes.
See the small overview below to get a rough overview of the areas of applications for THESEUS‑FE.
Due to its origin as an in-house software project at German car manufacturer BMW, THESEUS‑FE's roots lie in the automotive area. All major thermal management problems of interest during the operation of cars and other road vehicles can be simulated with THESEUS‑FE.
Some use cases for THESEUS‑FE in this field are:
Passenger comfort prediction has always been a key strength of THESEUS‑FE. This makes it the logical tool to use for simulating the thermal comfort of passengers in busses or trains. The physics governing heat transfer in a larger cabin environment are essentially the same as for smaller cars. The larger number of occupants is easily dealt with using our advanced GUI functionality to place virtual passengers in seated or standing positions.
Read more about the use of THESEUS‑FE in transportation vehicles
The demands on passenger aircraft HVAC systems are much higher than for ground vehicles. Environmental conditions vary within the extremes of +40 °C on the ground in tropical regions and -50 °C during flight at altitudes of several kilometers. To ensure safe conditions within the passenger cabin, the air pressure, temperature and oxygen level must be continuously monitored and controlled. The additional demands of a comfortable and enjoyable journey, rather than simply survivable conditions, require an even narrower range for these parameters.
THESEUS‑FE is used in aerospace industry and research primarily for evaluating the thermal comfort of passengers and validating different air conditioning concepts.
Read more about the usage of THESEUS‑FE used for simulating airplane cabins
Within the last few years new members have joined the THESEUS‑FE family. The goal of our efforts is turning car manufacturing into a transparent and easily controlled process, rather than relying on trial and error with physical prototypes. The new tools focus on the paint shop stage of car production.
Special tools are available to
Today civil engineering and architecture of a building includes energetic aspects. New buildings must not only be highly energy-efficient, but also guarantee thermal comfort of occupants. HVAC systems are now designed to cut down on energy usage while still maintaining comfortable temperature levels.
Possible applications of THESEUS‑FE for building design include:
THESEUS‑FE originated as a tool at car manufacturer BMW. Even today, most of our customers come from the automotive industry. The evolution of our software takes place in close cooperation with automotive customers, thus guaranteeing a product that precisely serves their needs. THESEUS‑FE is applicable to most thermal management problems that arise in the automotive design process.
Application cases for THESEUS‑FE in the automotive sector include:
Air conditioning of the passenger cabin is mostly about countering environmental conditions with appropriate HVAC systems. The challenge is to keep the cabin at comfortable conditions and to negate the effect of a cold or hot day, especially solar radiation. Various materials are investigated for their applicability in the car body. Different glasses and glass coatings are tested for their influence on the radiative energy transport into and out of the cabin. Climatization concepts are developed with the target of improving the comfort while reducing the required energy.
Doing these test virtually with THESEUS‑FE drastically reduce the cost in developing modern car climatization concepts.
See more about the applicability of THESEUS‑FE for car climatizationThe ultimate goal compartment climatization is guaranteeing thermal passenger comfort. This is why THESEUS-FE is delivered with the integrated virtual human thermal model FIALA-FE. Its task is to simulate the thermophysiological behavior of the human body, including response mechanisms such as sweating and shivering. Various models are available to judge the comfort state of the virtual thermal manikin. This allows quick and easy conclusions if a given cabin environment is judged to be comfortable or not.
Read more about the evaluation of thermal passenger comfortFor electric vehicles new thermal challenges arise, for example keeping the battery at a proper operating temperature. Since battery capacity is limited every tiny energy demand aside from keeping the car moving is put on the scales and judged again. Experience has shown that the energy consumed using traditional HVAC approaches may lower the effective range by up to 30%. Obviously innovative air-conditioning concepts and novel materials need to be investigated.
Read more about the use of THESEUS‑FE for electromobility applicationsThermal passenger comfort is an increasingly important topic in designing modern cars. To make imformed decisions concerning the HVAC layout the engineer first needs to understand the heat transfer mechanisms primarily responsible for cabin temperature and humidity. Simulations made with THESEUS‑FE support the thermal engineer by providing insight into the interplay of different environmental conditions, material properties and climatization effect. Extreme conditions such as a cold winter day in northern countries or a clear sunny day in tropical regions are easily applied by changing a few model parameters. Standard load cases specified by national or international regulation are easily defined.
For car climatization THESEUS‑FE treats all major heat transfer mechanisms that influence cabin temperature and humidity:
THESEUS-FE can easily be integrated in full-vehicle thermal simulation. One way - and probably the easiest one - is to use interfacing software TISC from TLK-Thermo GmbH.
The video demonstrates, how easy it is to prepare models in THESEUS-FE to exchange data trough TISC with coupling partners.
Typically in this scenario, THESEUS-FE simulates a 3D car model including all thermal physical effects acting on the car cabin. These include solar radiation, surface-to-surface radiation inside the cabin, convection on the outside caused by wind and/or driving speed and so on. For quick response times, often coarse meshes like the one used in the demonstration video are used. However, for detailled analyses, typical fine meshes with element number ranging in the millions can be used as well.
Cabins of modern cars are already well insulated thermally. As an example, consider a cross section through the complex layers in a typical car roof. Below the visible outer sheet material various layers are used for thermal insulation, noise protection and hollow spaces filled with air. Together with novel high-tech paints and coatings, this multi-layered composite buildup yields high insulation rates. These advances in insulation technologies of cars are the result of decades of research supported by simulation tools.
Nowadays, the biggest losses through thermal conduction occur through the windows. In comparison to that the remaining parts of the car cabin are already highly insulated.
Based on their wave-lenght and energy properties as well as their origin, two types of thermal radiation can be distiguished.
The infrared portions of thermal radiation heat exchange are commonly called "long-wave radiation". Within a car cabin all component parts exchange thermal radiation energy. A difference in temperature leads to a net radiative heat exchange seeking to equalize the temperatures. Besides this heat balancing between the components themselves, the cold sky withdraws energy from the outer car surfaces through long-wave radiation.
The visible parts of thermal radiation are gathered under the term "short-wave radiation" in THESEUS‑FE. Regarding the thermal simulation of cars, the sources for this type or radiation are mainly the sun or some other light sources. Solar radiation enters the cabin by transmission through the windows and is reflected and absorbed by opaque surfaces within the cabin. During a cold winter day this takes some burden from the HVAC system and works towards heating up the compartment. In contrast to this on a hot summer day the HVAC system has to counteract this additional energy input by cooling.
To achieve simulation results that are as close to reality as possible, THESEUS‑FE uses radiation models and material properties that are wave-length dependent. This effect is essential for car windows since the radiation transmitted through the glazing has a large influence on the heat balance of the cabin.
The air flow within the car cabin, when actively driven by the HVAC system, acts as a transport mechanism for heat between components. The technical term used for this effect is "forced convection". "Free convection" on the other hand occurs when a (buoyancy-driven) air flow arises solely through a difference in component temperatures and surrounding air. For example, this is observed in summer conditions when the dash board is heated to above cabin air temperature by the sun. Hot air at the material surface has a lower density than the surrounding air and rises as a consequence. For more accurately predicting flow patterns by simulation, THESEUS‑FE simulations can be coupled to a CFD solver (for example OpenFOAM or Star-CCM+). The Coupler module, part of the THESEUS‑FE suite, allows users to define and carry out co-simulation studies with a minimum of hassle.
A real time numerical analysis of vehicle cool-down performance
[english, 6.6 MB]
H.R. Shim, H. Pastohr
Hyundai Motor Company, P+Z Engineering
VTMS 8 (Vehicle Thermal Management Systems Conference and Exhibition) | May 20-24, 2007 | Nottingham, UK
The Influence of the Solar Radiation on the Interior Temperature of the Car
[english, 0.6 MB]
C. Neacşu, M. Ivanescu, I. Tabacu
SC Auto Chassis International, University of Piteşti
2009
An Optimised Thermal Design and Development Process for Passenger Compartments of Vehicles
[english, 1.4 MB]
P. J. Baker, M. D. Jenkins, S. Wagner, M. Ellinger
Flowmaster Limited, P+Z Engineering
EASC 2009 (European Automotive Simulation Conference) | July 06-07, 2009 | Munich, Germany
Idealisierte energetisch-analytische Abbildungsmethode der Temperaturschichtung bei der passiven Aufheizung in der Fahrzeugkabine
[german, 0.5 MB]
S. Wagner
P+Z Engineering
6. Tagung PKW-Klimatisierung | November 24, 2009 | Munich, Germany
Idealisierte energetisch-analytische Abbildungsmethode der Temperaturschichtung bei der passiven Aufheizung in der Fahrzeugkabine
[german, 0.8 MB]
S. Wagner
P+Z Engineering
November 24, 2009
Einfluss der regionalen Solarstrahlung auf den Pkw
[german, 0.3 MB]
M. Westerloh, J. Köhler
Volkswagen AG, TU Braunschweig
18. SIMVEC 2016 | November 22, 2016
Thermal comfort of passengers in cars, planes, busses and trains is getting more and more important. On the one hand it is an important selling point for mid-class and upper-class cars. On the other hand it is generally a fundamental aspect for customer satisfaction in any mode of tranportation. While a thermally comfortable environment often is not noticed consciously at all, an uncomfortable one certainly is.
New ways of improving the comfort within passenger compartments are constantly being researched. Specialized materials and coatings are checked for their suitability in reducing the negative effect of extreme environmental conditions. Examining their impact on the thermal conditions within a passenger cabin by simulation drastically reduces the costs when compared to physical experiments. The time necessary to test different variants is considerably reduced as well.
Determining the thermal conditions within passenger compartments is one thing. The other one is to combine these with the thermophysical sensation of a human being to get feedback about the sensed comfort level. With the thermal manikin FIALA-FE we offer a widely acclaimed virtual human thermal model based on the doctoral thesis by Dr. Dusan Fiala. This model, supplemented with a selection of comfort models, allows detailed analysis of the comfort sensation of human passengers.
Every human generates internal heat. In a simulation the amount of heat generated is lumped into a quantity called "activity level". The activity level can be thought of as an index of the intensitiy of work or action performed by the subject. Its unit is the MET, the Metabolic Equivalent of Task. It is normed such that the basal activity level in resting state lies between 0.8 and 1.0 MET. For heavy physical work and normal sports activities, values up to 10 met are reached. Within a car cabin simulation, typically one specifies a value of 1.2 MET for the driver and 1.0 MET for other passengers.
The human body together with its surroundings can be viewed as a thermal system.
Depending on the worn clothing, a human body is insulated from the surroundings at different rates.
Essential for the insulation effect are thin layers of air encased within the clothing layers.
In contrast to solid materials such as wool or any other fabric, air is a very bad conductor of heat and thus leads to high insulation values.
It has to be considered that this encased air is squeezed out in contact areas, e.g. when a person sits down onto a seat.
This translates into reduced clothing insulation effect in contact areas such as the seat.
On the other hand, the seat itself can be considered as a virtual additional clothing layer.
In extreme cases the insulation of the contact area is so effective that no heat is dissipated from the human body at all, ultimately
leading to sweating of the person sitting on the seat.
THESEUS‑FE allows its users to freely change the virtual human's clothing.
Typical compositions representing a summer and winter outfit come shipped with the software and are ready-to-use.
Many of the comfort models used in practice are based on a quasi-stationary point of view. That means that the short-term comfort behavior is neglected. An example for this is the cooling effect sensed in the seat contact area for a short time after sitting down. In the long run, due to the high insulation discussed above, heat accumulates and the human body might start to sweat.
A thermal system is said to be at neutral state when it is in thermal balance with its surroundings. For the human body this translates to the situation in which all internally generated metabolic heat is fully transferred to the surroundings and physiological regulatory mechanisms like sweating and shivering are turned off.
The comfort index PMV stands for "predicted mean vote" and stems from real-world trials with test persons rating their comfort sensations when exposed to different thermal conditions. The method was developed by Fanger and the results are presented on a seven-point scale from cold (-3) to hot (+3). The point of thermal neutrality is set to be at a PMV value of zero. The temperature of a human body (or rather that on its surface) remains contant over time at PMV=0.
Details on this kind of comfort value can be found in numerous standards, for example ASHRAE 55 and DIN EN ISO 7730.
The simplest statistical approach is to view the situation PMV=0 as the optimal case.
Every deviation from this state means more or less discomfort.
Another index by Fanger called PPD (for "percentage of persons dissatisfied") can be used to analyze the average comfort level.
It takes into account that a uniform comfort sensation for different people plainly does not exist and postulates that even at PMV=0 at least approx. 5% of the people will be dissatisfied with the thermal climate.
Another approach also available within THESEUS‑FE is to estimate the global comfort by using the mean skin temperature of the human.
Two models are the TS (thermal sensation) and DTS (dynamic thermal sensation) indices.
For judging the local comfort either the local skin temperature values (or their time derivatives) can be used.
Alternatively, the heat flow transmitted from the skin to the surroundings can be used.
Within a simulation with THESEUS‑FE the heat flow between the virtual human and its surroundings is split into four parts:
These heat flows are highly dependent on the surface temperature of the virtual human. For naked body parts (e.g. the hands) this is equal to the skin temperature. For clothed body parts it is the temperature of the clothing itself that is to be used.
Another quantity often used when evaluating the thermal comfort of a person is the so-called "equivalent temperature". In plain terms it is the temperature that one "actually feels". One reason for introducing this quantity is that the heat flow derived from a simulation on its own is not very meaningful for most people. Most people will tend to judge the sensation of heat by some kind of familiar temperature value. The definition of the equivalent temperature is inspired by the following question: How high would the temperature within an ideal, enclosed room with homogenous air and wall temperature and without forced air convection need to be to produce the same heat flow at the considered body part? This temperature value is then defined as the equivalent temperature of the body part in question.
THESEUS_FE supports several models for evaluating the local comfort. A well-known example is the Zhang model from UC Berkeley which basically rates the local skin temperatures of different body parts. In contrast to that, the index from ISO 14505 uses local equivalent temperatures and distinguishes between summer and winter clothing. A local comfort model based on equivalent temperatures has the benefit that each local comfort index of any body part can easily be traced back to the heat flow at its surface. This considerably simplifies the process of understanding the reasons for comfort or discomfort in a given situation.
The Application of Thermal Simulation Techniques for Seat Comfort Optimizations
[english, 0.6 MB]
S. Paulke, E. Kreppold
P+Z Engineering, BMW Group
2008
Simulation der Fahrzeugklimatisierung mit lokaler Komfortbewertung
[german, 6.0 MB]
S. Paulke, M. Ellinger, S. Wagner
P+Z Engineering
Thermomanagement im Automobil, CTI Forum | February 12-13, 2008 | Bonn, Germany
Auslegung und Beurteilung des thermischen Raumklimas in Fahrzeugen mit der Software THESEUS-FE
[german, 1.3 MB]
S. Paulke
P+Z Engineering
Haus der Technik Seminar | October 14, 2008 | Munich, Germany
Thermal Comfort Design and Assessment of Vehicle Cabins with THESEUS-FE
[english, 1.2 MB]
S. Paulke
P+Z Engineering
Haus der Technik Seminar | October 14, 2008 | Munich, Germany
The Influence of the Glass Material on the Car Passengers Thermal Comfort
[english, 2.1 MB]
C. Neacşu, M. Ivanescu, I. Tabacu
SC Auto Chassis International, University of Piteşti
2009
The Human Thermal Comfort Evaluation inside the Passenger Compartment
[english, 0.9 MB]
M. Ivanescu, C. Neacşu, S. Tabacu, I. Tabacu
University of Pitesti, SC Auto Chassis International
2010
Numerical Simulation of Car Cockpit Heating during Winter
[english, 0.8 MB]
C. Neacşu, M. Ivanescu, I. Tabacu
SC Automobile Dacia SA, University of Piteşti
2010
Studies of the Thermal Comfort inside of the Passenger Compartment using the Numerical Simulation
[english, 1.1 MB]
M. Ivanescu, C. Neacşu, I. Tabacu
University of Piteşti
Motors 2010 | October 7-9, 2010 | Kragujevac, Serbia
Comparative comfort simulations for winter load cases using global and local comfort models
[english, 4.0 MB]
S. Paulke
P+Z Engineering
Haus der Technik, 3. Tagung 'Fahrzeugklimatisierung' | May 07-08, 2019 | Essen, Germany