Ergonsim - Human Thermal Modelling
Application Domains

Simulation platform


Fast technological developments require novel ergonomic solutions. Endeavours related to human performance, safety, tolerance limits, thermal acceptability and occupant comfort have implications for sports science and sporting goods manufacturing, textile and clothing research, military applications, architecture, car and aerospace industries, meteorology, medical engineering, etc.


Ergonsim provides a thermophysiological simulation platform to aid the ergonomic design of new technical products and system control. Based on the extensively validated FPC Model the platform is a widely established simulation tool enabling systematic numerical investigations to study the impact of design variants, clothing, environmental and personal factors on human thermal, regulatory and perceptual responses including critical and extreme exposure conditions.


The platform’s open structure enables model extensions and adaptations to suit the specific needs of different industrial and research applications. Flexible definitions of the simulation boundary conditions and the customizable data exchange interfaces facilitate the integration with other simulation and measurement environments. Such advanced coupled systems equip measurement devices with ‘physiological intelligence’ and open up doors for computer-based, numerical analysis of complex processes such as human-environment thermal interactions not accessible to stand-alone simulation tools.


Sports applications


Sports play an important role in modern societies becoming an inherent part of our daily life with numerous benefits for our physical and mental health. Advances in the sports science and the development of new, high performance sportswear enable athletes to strive for new accomplishments and continue surpassing old records.


The performance, endurance and comfort of athletes involved in specific sports activities depends on numerous aspects including clothing, thermal, physiological and personal factors. The latter include e.g. the acclimatization status, fitness level, cardio-vascular capacity, and individual body characteristics.


State-of-the-art personalized thermophysiological simulation predicts crucial human responses for specific physical activities providing quantitative information on the impact of the various aspects. Stand-alone, or as part of body monitoring systems, thermophysiological simulation lends itself as a valuable tool for obtaining detailed insights on different influences potentially difficult to obtain in human subject tests. Apparel designers and sportswear manufacturers can then translate the critical new knowledge into innovative sports products.

sports simulation
core temperature exercise
sweating thermal manikin

Consequent integration of personalised thermophysiological simulation is a route for developing new generations of smart Personal Protective Equipment (PPE) systems. Future smart PPE may not only be able to monitor the actual thermophysiological status of the wearer but also contain predictive capabilities to generate appropriate alerts ahead of potentially dangerous situations. Customized numerical simulation is a useful method for processsing and interpreting recorded body status data. Together with info on the bodily most recent thermal history the data can serve e.g. to warn ahead firefighters exposed to intense radiation heat of the danger of skin burning by predicting the time left before overheated steam of sweat moisture is built within garments.

Clothing research


New textile materials and the development of specialized protective clothing systems require adequate advanced testing methods. Over the past decades thermal sweating manikins, though passively controlled, have become a gold standard for measuring the thermo-physical properties of garments.


Ergonsim has developed advanced coupling techniques to equip future manikins with ‘physiological intelligence’ necessary to mimic human thermal and regulatory behaviours so to enable clothing measurements under realistic human wear trial conditions. The new technology enables personal variations including the resultant heat exchange with the environment to be simulated cost-efficiently using a single manikin hardware setup. It opens up doors for new manikin applications such as physical simulation of personal exposures to dangerous conditions for which human subject tests are not feasible for ethical reasons.

clothing FPC Model
biometeorology UTCI

Similar endeavours are underway which are concerned with the development and establishment of thermal climate indices related to military applications and industrial heath and safety standards for outdoor workplaces.

Biometeorology


In human biometeorology, the combined effect of temperature, wind, humidity and solar radiation is important when assessing the thermal strain caused by outdoor weather on the human organism. There has been a growing need from multiple disciplines for a physiological response-based assessment index that adequately integrates the individual environmental influences and is valid across a broad spectrum of outdoor climate conditions including weather extremes [8].


The international activities culminated in the COST Action 730 of the European Science Foundation which developed and made available a widely valid assessment index for civil use in the major fields of human biometeorology-based on physiological principles and the “most advanced” models of human thermoregulation: the Universal Thermal Climate Index [13], UTCI.

building science

Architecture and building science


The FPC Model incorporates a first-principles, dynamic thermal comfort model developed to enable relevant thermal comfort analysis for different, even challenging, indoor climates including unconventional, non-moderate, heterogeneous, and/or transient conditions [4].


The model has been used to evaluate the thermal comfort conditions e.g. for the Olympics Stadium Australia in Sydney [3]; low-energy, passive downdraught evaporative cooling (PDEC) buildings in arid climates [2,10]; or indoor environments dominated by large glazed areas and high levels of solar irradiation [12].


Architects and engineers concerned with the development of new, low-energy conditioning concepts e.g. for solar architecture and/or climate-adapted, naturally ventilated buildings featuring diurnal temperature swings can deploy the FPC Model as a design tool to perform detailed thermal comfort analysis and optimize the specific indoor environments for occupant comfort.

Car comfort
passenger model

Advanced coupled simulation systems are capable of predicting human thermal and perceptual responses for such complex exposures as they have been validated specifically for the challenging conditions of the confined automobile and/or aircraft cabins [5,9].


Developers and engineers around the world deploy state-of-the-art simulation systems which use proprietary variants of the FPC Model to aid the design of energy-efficient HVAC systems and the development of new HVAC concepts for vehicles of the future [11].

Automotive and aerospace industries


Virtual development has become a key component of industrial product development processes. Given the financial pressures to achieve tough time and quality targets in today’s automotive and aerospace industries, integrated simulation systems coupling detailed thermal simulation of passenger compartments, HVAC systems simulation and thermophysiological comfort simulation of the occupants has become a state-of-the-art technology.


Vehicle thermal environments are susceptible to significant temporal fluctuations towards both hot and cold. Cabin occupants may furthermore be subjected to high levels of asymmetric solar radiation loads and are involved in complex cabin-occupant thermal interactions [6].

Forensic research


The FPC Model for forensic applications, FPC-FA, is a dedicated model version developed and validated against measured data [1] specifically for purposes of  forensic research. In the FPC-FA Model, bodily ‘life functions’ are 'switched off' to perform algor mortis simulations of the sole passive heat dissipation within body tissues and heat exchange with the environment, yet with the option for including simulations of pre-mortem scenarios.


Current standard PMI methods [7] are based on an insufficient thermophysical representation of the human body and a limited account of the actual exposure situation. The FPC-FA Model is capable of adequately simulating a wide variety of (male and female) body sizes and body compositions including children. The time-of-death (T-o-D) analysis can realistically consider even complex crime scene scenarios including e.g. temporal variations of ambient temperatures, inhomogeneous environmental and/or clothing conditions, and part- or whole-body water immersions. Spatial, transient removal of the bodily heat to objects in direct contact, can be modelled explicitly by means of coupled dynamic thermal simulation of objects such as floor slab constructions, etc.

time of death analysis

References

  1. Al-Alousi LME (1987) The post-mortem interval: A study of the body cooling rate and steroid degradation after death. Univ. Glasgow, Dept. Forensic Medicine and Science, chap. 3, pp. 39-197.

  2. Fiala D, Lomas KJ, Martinez D, Cook MJ (1999) Dynamic thermal sensation in PDEC buildings. Proc. PLEA '99 Intl. Conf. Passive and Low Energy Architecture, Brisbane (AUS), Vol. 1, pp. 243-248.

  3. Fiala D, Lomas KJ (1999) Application of a computer model predicting human thermal responses to the design of sports stadia. Proc. CIBSE '99 Nat. Conference, Harrogate (UK), pp. 492-499.

  4. Fiala D., Lomas K.J., and Stohrer M. (2003) First Principles Modeling of Thermal Sensation Responses in Steady-State and Transient Conditions. ASHRAE Trans. 109(I): 179-186

  5. Fiala D, Bunzl A., Lomas KJ, Cropper PC, Schlenz D (2003) A new simulation system for predicting human thermal and perceptual responses in vehicles. In: D Schlenz (ed). PKW-Klimatisierung III: Klimakonzepte, Regelungsstrategien und Entwicklungsmethoden. Haus der Technik Fachbuch Band 27, Expert Verlag, pp. 147-162.

  6. Fiala D, Psikuta A, Jendritzky G, Paulke S, Nelson DA, van Marken Lichtenbelt WD, Frijns AJH (2010) Physiological modeling for technical, clinical and research applications. Front. Biosci. S2: 939-968.

  7. Henssge C, Madea B (2004) Estimation of the time since death in the early post-mortem period. Forensic sci. internat. 144(2): 167-175.

  8. Jendritzky G., de Dear R., Havenith G (2012) UTCI - Why another thermal index? Intl J Biometeorol 56: 421-428.

  9. Lorenz M, Fiala D, Spinnler M, Sattelmayer T (2014) A coupled numerical model to predict heat transfer and passenger thermal comfort in vehicle cabins.SAE World Congress, SEA Internat., tech. pp. 2014-01-0664.

  10. Martinez D, Fiala D, Lomas KJ, Cook MJ (2000) Extended comfort envelopes for office buildings with passive downdraught evaporative cooling. Proc. RoomVent 2000, 7th Intl. Conf. Air Distribution in Rooms, Reading (UK), Vol. 1, pp. 53-58.

  11. Paulke S (2007) Finite Element Based Implementation of Fiala's Thermal Manikin in THESEUS-FE. VTMS 8, C640/083/2007 pp. 559-566, Chaados Publishing, Oxford, UK.

  12. Rees SJ, Lomas KJ, Fiala D (2008) Predicting local thermal discomfort adjacent to glazing. ASHRAE Trans. 114 (1): 431-441.

  13. Springer (2012) Universal thermal climate index (UTCI). Special Issue, Intl J Biometeorol 56(3).