Short- and long-wave radiation flux densities absorbed by people have a significant influence on their energy balance. The heat effect of the absorbed radiation flux densities is parameterised by the mean radiant temperature. This paper presents the physical basis of the RayMan model, which simulates the short- and long-wave radiation flux densities from the three-dimensional surroundings in simple and complex environments. RayMan has the character of a freely available radiation and human-bioclimate model. The aim of the RayMan model is to calculate radiation flux densities, sunshine duration, shadow spaces and thermo-physiologically relevant assessment indices using only a limited number of meteorological and other input data. A comparison between measured and simulated values for global radiation and mean radiant temperature shows that the simulated data closely resemble measured data.

/pdf/modelling-radiation-fluxes-in-simple-and-complex-g6gth4vara.pdf

Modelling radiation fluxes in simple and complex environments—application of the RayMan model

https://escholarship.org/content/qt5ts1r442/qt5ts1r442.pdf?t=lnq1j6

Thermal adaptation in the built environment: a literature review

Thermal stress is an important factor in many industrial situations, athletic events and military scenarios. It can seriously affect the productivity and the health of the individual and diminish tolerance to other environmental hazards. However, the assessment of the thermal stress and the translation of the stress in terms of physiological and psychological strain is complex. For over a century attempts have been made to construct an index, which will describe heat stress satisfactorily. The many indices that have been suggested can be categorized into one of three groups: "rational indices", "empirical indices", or "direct indices". The first 2 groups are sophisticated indices, which integrate environmental and physiological variables; they are difficult to calculate and are not feasible for daily use. The latter group comprises of simple indices, which are based on the measurement of basic environmental variables. In this group 2 indices are in use for over four decades: the "wet-bulb globe temperature" (WBGT) index and the "discomfort index" (DI). The following review summarizes the current knowledge on thermal indices and their correlates to thermal sensation and comfort. With the present knowledge it is suggested to adopt the DI as a universal heat stress index.

https://www.jstage.jst.go.jp/article/indhealth/44/3/44_3_388/_pdf

Thermal Comfort and the Heat Stress Indices

Existing procedures for the assessment of the thermal environment in the fields of public weather services, public health systems, precautionary planning, urban design, tourism and recreation and climate impact research exhibit significant shortcomings. This is most evident for simple (mostly two-parameter) indices, when comparing them to complete heat budget models developed since the 1960s. ISB Commission 6 took up the idea of developing a Universal Thermal Climate Index (UTCI) based on the most advanced multi-node model of thermoregulation representing progress in science within the last three to four decades, both in thermo-physiological and heat exchange theory. Creating the essential research synergies for the development of UTCI required pooling the resources of multidisciplinary experts in the fields of thermal physiology, mathematical modelling, occupational medicine, meteorological data handling (in particular radiation modelling) and application development in a network. It was possible to extend the expertise of ISB Commission 6 substantially by COST (a European programme promoting Cooperation in Science and Technology) Action 730 so that finally over 45 scientists from 23 countries (Australia, Canada, Israel, several Europe countries, New Zealand, and the United States) worked together. The work was performed under the umbrella of the WMO Commission on Climatology (CCl). After extensive evaluations, Fiala’s multi-node human physiology and thermal comfort model (FPC) was adopted for this study. The model was validated extensively, applying as yet unused data from other research groups, and extended for the purposes of the project. This model was coupled with a state-of-the-art clothing model taking into consideration behavioural adaptation of clothing insulation by the general urban population in response to actual environmental temperature. UTCI was then derived conceptually as an equivalent temperature (ET). Thus, for any combination of air temperature, wind, radiation, and humidity (stress), UTCI is defined as the isothermal air temperature of the reference condition that would elicit the same dynamic response (strain) of the physiological model. As UTCI is based on contemporary science its use will standardise applications in the major fields of human biometeorology, thus making research results comparable and physiologically relevant.

/pdf/utci-why-another-thermal-index-4vtze7w544.pdf

UTCI--why another thermal index?

A field study of thermal comfort in outdoor and semi-outdoor environments in subtropical Sydney Australia

Temperature and sensory indicates of human response to the thermal environment are often expressed in terms of the known response in a controlled laboratory environment, as a standard. The three rational indices of this type to be considered are ASHRAE's Standard Effective Temperature (SET*) Index, defined as the equivalent dry bulb temperature of an isothermal environment at 50% RH in which a subject, while wearing clothing standardized for activity concerned, would have the same heat stress (skin temperature T/sub sk/) and thermo-regulatory strain (skin wettedness, w) as in the actual test environment; Fanger's Predicted Mean Vote (PMV) Index, defined in terms of the heat load that would be required to restore a state of ''Comfort'' and evaluated by his Comfort Equation; and Winslow's Skin Wettedness Index of ''Thermal Discomfort'' (DISC) defined in terms of the fraction of the body surface, wet with perspiration, required to regulate body temperature by evaporative cooling.

A standard predictive index of human response to the thermal environment

Temperature and sensory indices of human responsee to the thermal environment are often expressed in terms of the known in a controlled laboratory environment, as a standard. The three rational indices of this type to be considered are (1) ASHARE's Standard Effective Temperature (SET*) Index, defined as the equivalent dry bulb temperature of an isothermal environment at 50% RH in wich a subject, while wearing clothing standardized for activity concerned, would have the same heat stress (skin temperature Tsk) and thermoregulatory strain (skin wettedness, w) as in the actual test environment; (2) Fanger's Predicted Mean Vote (PMV) Index, defined in terms of the heat load that would be required to restore a state of "Comfort" and evaluated by his Comfort Equation; and (3) Winslow's Skin Wettedness Index of "Thermal Discomfort" (DISC) defined in terms of the fraction of the body surface, wet with perspiration, required to regulate body temperature by evaporative cooling. The classic difference between PMV and DISC as predictors of warm discomfort occurs at very high and very low humidity but both lead to essentially the same judgment at average humidities (40-60% RH or 1-2 kPa). A new index PMV* is proposed for any dry or humid environment by simply replacing operative temperature To in Fanger's Comfort Equation with SET*. The use of PMV* as a sensor of heat stress and strain, is illustrated for typical HVAC situations and with a new Comfort-Humidity psychometric chart for indoor environments.

L. G. Berglund

Papers

A standard predictive index of human response to the thermal environment

A standard predictive Index of human reponse to thermal enviroment