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In this study a combined computational model of a room with virtual thermal manikin with real dimensions and physiological shape was used to determine heat and mass transfer between human body and environment. Three dimensional fluid flow, temperature and moisture distribution, heat transfer (sensible and latent) between human body and ambient, radiation and convection heat transfer rates on human body surfaces, local and average convection coefficients and skin temperatures were calculated. The radiative heat transfer coefficient predicted for the whole-body was 4.6 W m(-2) K-1, closely matching the generally accepted whole-body value of 4.7 W m(-2) K-.(-1) Similarly, the whole-body natural convection coefficient for the manikin fell within the mid-range of previously published values at 3.8 W m(-2) K-1. Results of calculations were in agreement with available experimental and theoretical data in literature. (C) 2008 Elsevier Ltd. All rights reserved.

In this study, apart from the other studies related to thermal comfort, it is combined that the fundamental equations given in the steady-state energy balance and the empirical relations expressing effects of the thermoregulatory control mechanisms of the body. In the first section of this simulation, body core temperature is calculated by using the equations expressing thermoregulatory control mechanism, the required skin temperature and sweat rate values. Variation of the calculated body core temperature is investigated with the activity level based on required skin temperature and sweat rate values. In the second section of the simulation, heat losses from the body (convection, radiation, evaporation, and respiration) and ratio of the each heat loss mechanism to total heat loss are calculated and discussed in detail.

Determination of heat transfer rate and Nusselt number in the thermal entry region in ducts is considered. Alternative relations are derived to calculate the rate of heat transfer and Nusselt number. An approximate equation is proposed for the calculation of mean and local Nusselt number in all range of the axial distance in the thermal entry region in ducts with constant surface temperature. And the use of this correlation is extended to predict mean and local Nusselt number in the thermal entry region in tubes with constant wall heat flux

The human thermal environment can be represented by the air temperature, radiant temperature, air velocity, humidity, clothing and activity. This has implications for health, comfort and performance. An understanding of human thermoregulatory processes facilitates the design and development of improved heating and cooling systems. This study presents a computational model of thermal interactions between a human and the interior environment. The model is based on the heat balance equation for human body with different types of clothing ensembles, combined with empirical equations defining the sweat rate and mean skin temperature. Simulation has been performed by the use of steady state conditions, and two different posture positions, namely sitting and standing, are considered in this study. Results are in good agreement with available experimental data. The parametric studies show that the methodology described can provide an effective means for simulating thermal comfort level.

In an absorption cooling system, simultaneous heat and mass transfer operations take place in the absorber and generator. The performance of an absorber is of paramount importance on the coefficient of performance and the manufacturing cost of an absorption machine. Increasing heat and mass transfer coefficients in an absorber decreases the heat transfer area of the absorber, as a result of this the cost of the system can be reduced. The absorption of water vapor in aqueous solutions of lithium bromide is modelled for a falling-film, vertical-tube absorber. Heat and mass transfer coefficients are determined by calculating temperature and concentration variations at the falling film in the absorber. Then mean Nusselt and Sherwood numbers are determined to see the changes in the heat and mass transfer. Subsequently, a modular computer program has been developed for absorption systems to simulate various cycle configurations and absorber parameters. So, the effect of hot water, chilled water and cooling water inlet temperatures on the coefficients of performance, Nusselt and Sherwood numbers and the surface area of the absorber are studied with the simulation program. The results can be used to optimise the commercial absorption chillers.