Increased pressure on the available limited water resources for agricultural production has a significant impact on sugarcane production. Routine monitoring of evaporation with reliable accuracy is essential for irrigation scheduling, for more efficient use of the available water resources and for management purposes. An indirect method for estimating evaporation involves measuring the sensible heat flux (H) from which latent energy flux and hence total evaporation can be calculated, as a residual using the shortened energy balance from measurements of net irradiance and soil heat flux. Various methods for measuring H may include Bowen ratio energy balance, eddy covariance (EC), flux variance (FV), optical scintillation, surface renewal (SR) and temperature variance (TV). Each method has its own advantages and disadvantages, in terms of method theoretical assumptions, accuracy, complexity, cost, fetch requirements and power consumption. The TV and SR methods are inexpensive and reasonably simple with a reduced power requirement compared to other methods since they require high frequency air temperature data which is obtained by using an unshielded naturally-ventilated type-E fine-wire thermocouple at a single point above the canopy surface. The TV method is based on the Monin-Obukhov similarity theory (MOST) and uses the mean and standard deviation of the air temperature for each averaging period. Currently, there are two TV methods used for estimating sensible heat flux (HTV) at sub-hourly time intervals, one includes adjustment for stability, and a second that includes adjustment for air temperature skewness. Another method used to estimate sensible heat flux from the mean and standard deviation of air temperature is based on MOST and uses spatial second-order air temperature structure function. For the TV method adjusted for stability and the method based on MOST that uses a spatial second-order air temperature structure function, the Monin-Obukhov atmospheric stability parameter () is needed. The parameter  can be estimated from EC measurements or alternatively estimated independently using an iteration process using horizontal wind speed measurements. The TV method including adjustment for air temperature skewness requires the mean and standard deviation of the air temperature and air temperature skewness for each averaging time period as the only input. The SR method is based on the coherent structure concept. Currently, there are various SR models method for estimating sensible heat flux. These include an ideal SR analysis model method based on an air temperature structure function analysis, the SR analysis model with a finite micro-front period, combined SR with K-theory and combined SR model method based on MOST. The ideal SR analysis model based on an air temperature structure function analysis should be calibrated to determine the SR weighting factor (). The other SR approaches require additional measurements such as crop height and horizontal wind speed measurements. In all of the SR approaches, air temperature time lags are used when calculating the air temperature structure functions. In this study, the performance of TV and SR methods were evaluated for estimation of sensible heat and latent energy fluxes at different heights for air temperature time lags of 0.4 and 0.8 s for daytime unstable conditions against EC above a sugarcane canopy at the Baynesfield Estate in KwaZulu-Natal, South Africa. For all methods, latent energy flux (LE) and hence evaporation was estimated as a residual from the shortened energy balance equation using H estimates and net irradiance and soil heat flux density measurements. The ideal SR analysis model method based on an air temperature structure function analysis approach was calibrated and validated against the EC method above the sugarcane canopy using non-overlapping data sets for daytime unstable conditions during 2008. During the calibration period, the SR weighting factor was determined for each height and air temperature time lag. The magnitude of ranged from 0.66 to 0.55 for all measurement heights and an air temperature time lag of 0.8 s. The value increased with a decrease in measurement height and an increase in air temperature time lag. For the validation data set, the SR sensible heat flux (HSR) estimates corresponded well with EC sensible heat flux (HEC) for all heights and both air temperature time lags. The agreement between HSR and HEC improved with a decrease in measurement height for the air temperature time lag of 0.8 s. The best HSR vs HEC comparisons were obtained at a height of 0.20 m above the crop canopy using = 0.66 for an air temperature time lag of 0.8 s. The residual estimates of latent energy flux by SR and EC methods were in good agreement. The LESR at a height of 0.20 m above the canopy yielded the best comparisons with LEEC estimated as a residual. The performance of the TV method, including adjustment for stability, and / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2010.

The demand for the world’s increasingly scarce water supply is rising rapidly, challenging its availability for agriculture and other environmental uses, especially in water scarce countries, such as South Africa, with mean annual rainfall is well below the world’s average. The implementation of effective and sustainable water resources management strategies is then imperative, to meet these increasingly growing demands for water. Accurate assessment of evaporation is therefore crucial in agriculture and water resources management. Evaporation may be estimated using different micrometeorological methods, such as eddy covariance (EC), Bowen ratio energy balance (BR), surface renewal (SR), flux variance (FV), and surface layer scintillometry (SLS) methods. Despite the availability of different methods for estimating evaporation, each method has advantages and disadvantages, in terms of accuracy, simplicity, spatial representation, robustness, fetch, and cost. Invoking the shortened surface energy balance equation for which advection and stored canopy heat fluxes are neglected, the measurement of net irradiance, soil heat flux, and sensible heat flux allows the latent energy flux and hence the total evaporation amount to be estimated. The SR method for estimating sensible heat, latent energy, and other scalars has the advantage over other micrometeorological methods since it requires only measurement of the scalar of interest at one point. The SR analysis for estimating sensible heat flux from canopies involves high frequency air temperature measurements (typically 2 to 10 Hz) using 25 to 75 ìm diameter fine-wire thermocouples. The SR method is based on the idea that parcel of air near a surface is renewed by an air parcel from above. The SR method uses the square, cube, and fifth order of two consecutive air temperature differences from different time lags to determine sensible heat flux. Currently, there are three SR analysis approaches: an ideal SR analysis model based on structure function analysis; an SR analysis model with finite micro-front period; and an empirical SR analysis model based on similarity theory. The SR method based on structure function analysis must be calibrated against another standard method, such as the eddy covariance method to determine a weighting factor á which accounts for unequal heating of air parcels below the air temperature sensor height. The SR analysis model based on the finite micro-front time and the empirical SR analysis model based on similarity theory need the additional measurement of wind speed to estimate friction velocity. The weighting factor á depends on measurement height, canopy structure, thermocouple size, and the structure function air temperature lag. For this study, á for various canopy surfaces is determined by plotting the SR sensible heat flux SR H against eddy covariance EC H estimates with a linear fit forced through the origin. This study presents the use of the SR method, previously untested in South Africa, to estimate sensible heat flux density over a variety of surfaces: grassland; Triffid weed (Chromolaena odorata); Outeniqua Yellow wood (Podocarpus Falcatus) forest; heterogeneous surface (Jatropha curcas); and open water surface. The sensible heat flux estimates from the SR method are compared with measurements of sensible heat flux obtained using eddy covariance, Bowen ratio, flux variance, and surface layer scintillometer methods, to investigate the accuracy of the estimates. For all methods used except the Bowen ratio method, evaporation is estimated as a residual using the shortened energy balance from the measured sensible heat and from the additional measurements of net irradiance and soil heat flux density. Sensible heat flux SR H estimated using the SR analysis method based on air temperature structure functions at a height of 0.5 m above a grass canopy with a time lag r = 0.5 s, and á =1 showed very good agreement with the eddy covariance EC H , surface layer scintillometer SLS H , and Bowen ratio BR H estimates. The half-hourly latent energy flux estimates obtained using the SR method SR ë E at 0.5 m above the grass canopy for a time lag r = 0.5 s also showed very good agreement with EC ë E and SLS ë E . The 20-minute averages of SR ë E compared well with Bowen ratio BR ë E estimates. Sensible heat and latent energy fluxes over an alien invasive plant, Triffid weed (C. odorata) were estimated using SR , EC , FV and SLS methods. The performance of the three SR analysis approaches were evaluated for unstable conditions using four time lags r = 0.1, 0.4, 0.5, and 1.0 s. The best results were obtained using the empirical SR method with regression slopes of 0.89 and root mean square error (RMSE) values less than 30 W m-2 at measurement height z = 2.85 and 3.60 m above the soil surface for time lag r = 1.0 s. Half-hourly SR H estimates using r = 1.0 s showed very good agreement with the FV and SLS estimates. The SR latent energy flux, estimated as a residual of the energy balance ë ESR , using time lag r = 1.0 s provided good estimates of EC ë E , FV ë E , and SLS ë E for z = 2.85 and 3.60 m. The performance of the three SR analysis approaches for estimating sensible heat flux above an Outeniqua Yellow wood stand, were evaluated for stable and unstable conditions. Under stable conditions, the SR analysis approach using the micro-front time produced more accurate estimates of SR H than the other two SR analysis approaches. For unstable conditions, the SR analysis approach based on structure functions, corrected for á using EC comparisons produced superior estimates of SR H . An average value of 0.60 is found for á for this study for measurements made in the roughness sublayer. The SR latent energy flux density estimates SR ë E using SR H based on structure function analysis gave very good estimates compared with eddy covariance ( EC ë E ) estimates, with slopes near 1.0 and RMSE values in the range of 30 W m-2. The SR ë E estimates computed using the SR analysis approach using the micro-front time also gave good estimates comparable to EC ë E . The SR and EC methods were used to estimate long-term sensible heat and latent energy flux over a fetch-limited heterogeneous surface (J. curcas). The results show that it is possible to estimate long-term sensible heat and latent energy fluxes using the SR and EC methods over J. curcas. Continuous measurements of canopy height and leaf area index measurements are needed to determine á . The weighting factor á was approximately 1 for placement heights between 0.2 and 0.6 m above the Jatropha tree canopy. The daily sensible heat and latent energy flux estimates using the SR analysis gave excellent estimates of daily EC sensible heat and latent energy fluxes. Measurements of sensible heat and estimates of the latent energy fluxes were made for a small reservoir, using the SR and EC methods. The SR sensible heat flux SR H estimates were evaluated using two air temperature time lags r = 0.4 and 0.8 s at 1.0, 1.3, 1.9, 2.5 m above the water surface. An average á value of 0.175 for time lag r = 0.4 s and 0.188 for r = 0.8 s was obtained. The SR H and EC H estimates were small (-40 to 40 W m-2). The heat stored in water was larger in magnitude (-200 to 200 W m-2) compared to the sensible heat flux. The SR and EC latent energy fluxes were almost the same in magnitude as the available energy, due to the small values of the sensible heat fluxes. The daily evaporation rate ranged between 2.0 and 3.5 mm during the measurement period. The SR method can be used for routine estimation of sensible heat and latent energy fluxes with a reliable accuracy, over a variety of surfaces: short canopies, tall canopies, heterogeneous surface, and open water surface, if the weighting factor á is determined. Alternatively, the SR method can be used to estimate sensible heat flux which is exempt from calibration using the other two SR analysis approaches, with additional measurement of wind speed for estimating friction velocity iteratively. The advantages of the SR method over other micrometeorological methods are the relatively low cost, easy installation and maintenance, relatively low cost for replicate measurements. These investigations may pave the way for the creation of evaporation stations from which real-time and sub-hourly estimates of total evaporation may be obtained relatively inexpensively. / Thesis (Ph.D.)-University of KwaZulu-Natal, Pietermaritzburg, 2008.

Driving with the cold engine increases fuel consumption and greenhouse gases emissions. A latent heat energy storage device has been proposed to recover waste heat and reduce engine warm-up time by using phase change materials (PCMs) as an energy storage medium. Two types of paraffin waxes and 50/50 mixture of the two have been examined to characterize their behaviors under repetitive heating/freezing. From the results, the heat transfer is more effective in the case of narrower spacing distances between the cooling plates and high circulating flow rate of the heat transfer fluid. A 50/50 mixture of two paraffin waxes also provides better heat transfer due to the possible existence of both conduction and natural convection. The results of the metal block simulation experiments demonstrated the potential of latent heat TES’s for use in engine warm-up.

Driving with the cold engine increases fuel consumption and greenhouse gases emissions. A latent heat energy storage device has been proposed to recover waste heat and reduce engine warm-up time by using phase change materials (PCMs) as an energy storage medium. Two types of paraffin waxes and 50/50 mixture of the two have been examined to characterize their behaviors under repetitive heating/freezing. From the results, the heat transfer is more effective in the case of narrower spacing distances between the cooling plates and high circulating flow rate of the heat transfer fluid. A 50/50 mixture of two paraffin waxes also provides better heat transfer due to the possible existence of both conduction and natural convection. The results of the metal block simulation experiments demonstrated the potential of latent heat TES’s for use in engine warm-up.

The focus of the research is on investigations of various methods for obtaining sensible heat flux (H) for estimating evaporation. The key for this approach is the application of the shortened energy balance equation, and in the case of methods based on the Monin-Obukhov similarity theory (MOST), such as surface-layer scintillometrv and temperature variance with adjusted for stability using air temperature skewness, and surface renewal (SR), die iterative procedures. The application of the shortened energy balance requires that errors associated with measurement of net irradiance (Rnet) and soil heat flux (S) are kept to a minimum To this end. methodology for the calibration of net radiometers for both the infrared and short wave irradiances receive attention. A field study attempts to quantify the error in soil heat flux measurement for a mesic grassland. A standard, convenient and accurate method for calibrating net radiometers would assist in unravelling reasons for the perplexing lack of surface energy balance closure when employing the eddy covariance (EC) flux estimation method as well as improve on the accuracy of the energy balance residual method for estimating evaporation. A relatively inexpensive, accurate and quick laboratory method, based on physical theory, for non-steady radiative conditions above a large water-heated or water-cooled radiator containing circulated water, with surface-embedded thermocouples is used to obtain reproducible net radiometer calibration factor's for the infrared waveband for a wide range in net irradiance. When applied, the method would reduce error m the most important term of the shortened energy balance and assist in energy balance closure aspects of EC measurements. The SLS method, reliant on MOST, is used for estimating a really-averaged H for a mesic grassland for a 30-month period. Comparisons with EC measurements feature prominently in this unique study. These comparisons include using different MOST procedures and the influence of the Bowen ratio on SLS measurement: of if is investigated. Furthermore, since there are reports in the literature that the EC method may underestimate H and or latent energy flux (LE), resulting in the shortened energy balance not being closed, effort is devoted to this aspect. Other methods used for comparison purposes are the traditional Bowen ratio energy balance (BREB), SR, TV and ETo (grass reference) methods. The TV and SLS and/or EC measurements of H are compared above three contrasting canopy surfaces. It is shown that other high frequency air temperature-based methods, for example, for the first time the TV method with adjustment for skewness, may pave the way for evaporation stations from which real-time and sub-hourly estimates may be obtained relatively inexpensively. Another area of research that receives attention is the placement height of EC instruments above short-canopy surfaces and a spectral analysis of the vertical wind speed and some temperature measurement: for close-canopv placement heights. The SR method is used to estimate, for the first time, open-water evaporation. The ideal SR method applied above canopies is the most inexpensive micrometeorological method for estimating H, but the SR weighting factor a needs to be determined using EC and for this reason, the TV method with adjustment for skewness was investigated. Finally, a unique implementation of SR uses an iterative method for calculating H. A similar iterative procedure is applied for MOST and ETo calculations. / Thesis (DScAgric)-University of KwaZulu-Natal, Pietermaritzburg, 2010.

The impact of cold climate on physical and biological processes, especially the role of air and soil temperature in recovering photosynthesis and transpiration in boreal forests, was investigated in a series of studies. A process-based ecosystem model (CoupModel) considering atmospheric, soil and plant components was evaluated and developed using Generalized Likelihood Uncertainty Estimation (GLUE) and detailed measurements from three different sites. The model accurately described the variability in measurements within days, within years and between years. The forcing environmental conditions were shown to govern both aboveground and belowground processes and regulating carbon, water and heat fluxes. However, the various feedback mechanisms between vegetation and environmental conditions are still unclear, since simulations with one model assumption could not be rejected when compared with another. The strong interactions between soil temperature and moisture processes were indicated by the few behavioural models obtained when constrained by combined temperature and moisture criteria. Model performance on sensible and latent heat fluxes and net ecosystem exchange (NEE) also indicated the coupled processes within the system. Diurnal and seasonal courses of eddy flux data in boreal conifer ecosystems were reproduced successfully within defined ranges of parameter values. Air temperature was the major limiting factor for photosynthesis in early spring, autumn and winter, but soil temperature was a rather important limiting factor in late spring. Soil moisture and nitrogen showed indications of being more important for regulating photosynthesis in the summer period. The need for systematic monitoring of the entire system, covering both soil and plant components, was identified as a subject for future studies. The results from this modelling work could be applied to suggest improvements in management of forest and agriculture ecosystems in order to reduce greenhouse gas emissions and to find adaptations to future climate conditions. / QC 20110921 / the Nitro-Europe project

Resumo: Considerando a importância da compreensão da dinâmica espaço temporal dos componentes do balanço de energia (BE) em escala regional para o gerenciamento de recursos hídrico e o manejo agrícola, o objetivo principal desta tese foi construir e analisar uma série temporal dos componentes do BE adequada às condições de clima subtropical úmido do Estado do Rio Grande do Sul. Para tanto, inicialmente foi avaliada a adequação de modelos de estimativa de BE para o Estado. Nesta etapa foram utilizados produtos MODIS e dados de referência medidos em uma torre micrometeorológica instalada em Cruz Alta – RS, usando valores instantâneos para um período de estudo de 2009 a 2011. Na sequência foi avaliada a adequação dos modelos em representar a variabilidade espacial dos componentes do BE. Nesta etapa foram usados produtos MODIS, dados de reanálise ERA Interim, dados de referência da torre micrometeorológica e dados de estações meteorológicas do INMET, para o mesmo período de estudo. Na última etapa do trabalho foi construída a série temporal dos componentes do BE usando o modelo METRIC, a qual abrangeu um período de 14 anos, de 2002 a 2016. Os resultados demonstraram que os três modelos analisados apresentam coerência com as medidas de referência, sendo as maiores limitações apresentadas pelo modelo SEBAL, as quais se atribui principalmente às condições ecoclimáticas do Estado e a baixa resolução espacial das imagens. Na análise da variabilidade espacial, o modelo METRIC apresentou maior consistência nos resultados e proporcionou maior número de dias com resultados válidos, sendo assim apontado como o mais apto para realização do restante do estudo. A série temporal construída possibilitou a compreensão dos padrões de distribuição espaço temporal dos componentes do BE no estado do Rio Grande do Sul. Há uma marcada sazonalidade nos componentes do BE, com maiores valores no verão e menores no inverno. G (fluxo de calor no solo) é o componente de menor magnitude e sua distribuição espacial e temporal é determinada pela distribuição de Rn (saldo de radiação). Já os componentes LE (fluxo de calor latente) e H (fluxo de calor sensível), são os que mostram magnitude maior e apresentam padrões de distribuição espacial e temporal coerentes com as condições climáticas e com os tipos de uso e cobertura na área de estudo. Observase um padrão inverso, com um gradiente de LE no sentido noroeste para sudeste e para o componente H, no sentido sudeste para noroeste. Sendo estas informações de grande importância para gerenciamento de recursos hídricos em escala regional, para estudos de zoneamento agrícola. / Abstract: Given the importance of understanding the temporal and spatial dynamics of of the energy balance (EB) components in a regional scale for the management of water resources and agricultural, the main objective of this thesis was to construct and analyze a time series of the components of BE appropriate to the subtropical humid climate conditions of the State of Rio Grande do Sul. In order to reach the objective initially, the adequacy of the models for the humid climate conditions was evaluated, in this step we used MODIS data and reference data measured in a micrometeorological tower installed in Cruz Alta - RS. The analyzes performed with instantaneous values and the study period was from 2009 to 2011. The next step evaluate the spatial variability of the BE components, the data used were the MODIS products, ERA Interim reanalysis data, reference data of the micrometeorological tower and INMET meteorological stations, for the same study period. In the last stage the time series of the BE components was constructed from the METRIC model. The period series was 14 years from 2002 to 2016.The results showed that the three models analyzed were consistent with the reference measurements, with the greatest limitations presented by the SEBAL model, which are mainly attributed to the state's eco-climatic conditions and the low spatial resolution of the images In the analysis of the spatial variability, the METRIC model presented greater consistency in the results and provided greater number of days with valid results, this model thus indicated as the most suitable for the rest of the study. The time series constructed allowed us to understand the temporal distribution patterns of BE components in the state of Rio Grande do Sul. There is a marked seasonality in the BE components, with higher values in summer and lower in winter. G is the smallest magnitude component and its spatial and temporal distribution is determined by the Rn distribution. On the other hand, the LE and H components are those that show higher magnitude and present spatial and temporal distribution patterns consistent with the climatic conditions and the types of use and coverage in the study area. An inverse pattern is observed, with a LE gradient from north-west to south-east and for H-component, from southeast to northwest.

Terrestrial evapotranspiration (ET) is a significant component of the energy and water balances at the land surface. However, direct, continuous measurements of ET are spatially limited and only available since the 1990s. Due to this lack of observations, detecting and attributing long-term regional trends in ET remains difficult. This dissertation aims to alleviate the data limitation and detect long-term trends by developing a method to infer ET from data collected at common weather stations, which are spatially and temporally abundant. The methodology used to infer ET from historical meteorological data is based on an emergent relation between the land surface and atmospheric boundary layer. We refer to this methodology as the Evapotranspiration from Relative Humidity at Equilibrium method, or the “ETRHEQ method”. In the first section of this dissertation, we develop the ETRHEQ method for use at common weather stations and demonstrate the utility of the method at twenty eddy covariance sites spanning a wide range of climate and plant functional types. Next, we apply the ETRHEQ method at historical weather stations across the continental U.S. and show that ET estimates obtained via the ETRHEQ method compare well with watershed scale ET, as well as ET estimates from land surface models. From 1961 to 1997, we find negligible or increasing trends in summertime ET over the central U.S. and the west coast and negative trends in the eastern and western U.S. From 1998 to 2014, we find a sharp decline in summertime ET across the entire U.S. We show that this decline is consistent with decreasing transpiration associated with declines in humidity. Lastly, we assess the sensitivity of ET to perturbations in soil moisture and humidity anticipated with climate change. We demonstrate that the response of ET to changing humidity and soil moisture is strongly dependent on the biological and hydrological state of the surface, particularly the degree of water stress and vegetation fraction. In total, this dissertation demonstrates the utility of the ETRHEQ method as a means to estimate ET from weather station data and highlights the critical role of vegetation in modulating ET variability.

abstract: Nanoparticle suspensions, popularly termed “nanofluids,” have been extensively investigated for their thermal and radiative properties. Such work has generated great controversy, although it is arguably accepted today that the presence of nanoparticles rarely leads to useful enhancements in either thermal conductivity or convective heat transfer. On the other hand, there are still examples of unanticipated enhancements to some properties, such as the reported specific heat of molten salt-based nanofluids and the critical heat flux. Another largely overlooked example is the apparent effect of nanoparticles on the effective latent heat of vaporization (hfg) of aqueous nanofluids. A previous study focused on molecular dynamics (MD) modeling supplemented with limited experimental data to suggest that hfg increases with increasing nanoparticle concentration. Here, this research extends that exploratory work in an effort to determine if hfg of aqueous nanofluids can be manipulated, i.e., increased or decreased, by the addition of graphite or silver nanoparticles. Our results to date indicate that hfg can be substantially impacted, by up to ± 30% depending on the type of nanoparticle. Moreover, this dissertation reports further experiments with changing surface area based on volume fraction (0.005% to 2%) and various nanoparticle sizes to investigate the mechanisms for hfg modification in aqueous graphite and silver nanofluids. This research also investigates thermophysical properties, i.e., density and surface tension in aqueous nanofluids to support the experimental results of hfg based on the Clausius - Clapeyron equation. This theoretical investigation agrees well with the experimental results. Furthermore, this research investigates the hfg change of aqueous nanofluids with nanoscale studies in terms of melting of silver nanoparticles and hydrophobic interactions of graphite nanofluid. As a result, the entropy change due to those mechanisms could be a main cause of the changes of hfg in silver and graphite nanofluids. Finally, applying the latent heat results of graphite and silver nanofluids to an actual solar thermal system to identify enhanced performance with a Rankine cycle is suggested to show that the tunable latent heat of vaporization in nanofluilds could be beneficial for real-world solar thermal applications with improved efficiency. / Dissertation/Thesis / Doctoral Dissertation Mechanical Engineering 2015

Resumo: Foi estudada a eliminação de calor latente e estimado o fluxo térmico total ao sol e à sombra em cabras da raça Saanen mantidas em ambiente tropical, visando determinar importância da termólise evaporativa para esses animais e proporcionar subsídios para o estabelecimento de métodos de manejo em ambiente tropical. A evaporação total foi determinada por processo gravimétrico, usando-se um sistema de pesagem de precisão. A evaporação cutânea foi obtida por determinação direta através de uma cápsula ventilada; e a evaporação respiratória estimada a partir do fluxo térmico entre aparelho respiratório e o ambiente; determinaram-se ainda a estocagem térmica e as trocas convectivas e radiativas. Por ocasião de cada determinação, foram registradas a temperatura retal, a freqüência respiratória e a temperatura da superfície corporal, bem como variáveis ambientais: temperatura e umidade do ar, velocidade do vento e temperatura do globo negro. Foram avaliadas as características morfológicas do pelame (espessura da capa, comprimento médio, densidade numérica e ângulo dos pêlos) para cada animal. As análises estatísticas basearam-se no método dos quadrados mínimos para dados não-balanceados, tendo o modelo linear geral proposto incluído os efeitos: ambiente (fixo), animal (aleatório), interação animal x ambiente e regressão sobre a temperatura do ar, a umidade relativa, a temperatura radiante média, a temperatura da superfície corporal, a temperatura retal, a freqüência respiratória e a idade do animal, além das características morfológicas do pelame, no caso da evaporação cutânea. A termólise evaporativa compreendeu 61,5% da perda de calor para o ambiente, sendo a única via de perda térmica possível ao sol sob temperaturas radiante média acima de 35ºC...(Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The present work aimed at to study the elimination of latent heat and esteem the total thermal flow to the sun and the shade in Saanen goats in tropical environment, to determine importance of evaporative heat loss these animals and to provide subsidies for the establishment of methods of handling in tropical environment. The total evaporation was determined by means of gravimetrical process, for a weighing system of precision. The cutaneous evaporation was gotten by direct determination, by means of a ventilated capsule; the respiratory evaporation gotten by calculations of heat flow of respiratory device for environment. It was determined still the heat storage and the convective and radiative exchanges. For occasion of each determination, the rectal temperature, respiratory rate and surface temperature of the animal, as well as meteorological data: air temperature, relative humidity, wind speed and black globe temperature were register. The morphologic characteristics of the hair coat (coat thickness, hair length, numerical density and hair angle to skin) had been evaluated for each animal. The statistical analyses were carried through by the lest-squares method for not-balanced data. The considered model included the effect of environment and animal and the covariates: air temperature, relative humidity, mean radiating temperature, surface temperature, rectal temperature, respiratory rate and age of animal, beyond the morphologic characteristics of the hair coat for cutaneous evaporation. Heat loss evaporative understands 62.2% of the heat carried for environment exchange, being the way possible to the sun under radiant temperatures above of 35º...(Complete abstract, click electronic access below) / Orientador: Roberto Gomes da Silva / Coorientador: Danísio Prado Munari / Banca: Iran Jose Oliveira da Silva / Banca: Orlando Rus Barbosa / Banca: Isabel Cristina Boleli / Banca: Renato Luis Furlan / Doutor