The study is experimentally inclined, with a high target precision for performance measurement. A comprehensive programme of measurements was carried out in a two-storey building, having a massive structure and dating from 1970. Measurements were made continuously during the heating season from a total of about 70 points. Readings were taken every 30 seconds, and the mean values stored in a computer every 15 minutes. Analysis of the results have been concentrated on: * Thermal inertia, and particularly that of cooling mechanisms. * Time delays in heat flows through the building envelope in response to variations in ambient temperature. * The amount of solar input beneficially retained when operating with night setback and with normal operation. The results indicate that the building has both a long time constant, of about 200 h, and a short one, of about 1.5 h. The magnitude of the shorter time constant depends on the thermal capacity of the interior of the building (furniture, curtains etc.), and can be regarded as having some validity for other apartment building stock. Analyses of temperature gradients in the internal surfaces of the exterior walls indicate that the building's ventilation system, which was originally constructed as an exhaust air ventilation system, but with the inflow of fresh air blocked off, generates a dynamic insulation effect. Calculations indicate that this effect can provide a saving of 6 % of the total heating requirement, excluding that for domestic hot water. Investigation of the static heat requirement with and without night set-back indicate a considerable potential annual saving of heating energy, amounting to a maximum of 13 %, provided that the building is heated in accordance with a prescribed strategy. A 'comfort indoor temperature' has also been determined, being the temperature above which the occupants of the building consume excessive heating energy. Theoretical models have been derived to illustrate the short time constant and to analyse the dynamic insulation effect noted. / <p>Diss. Umeå : Umeå universitet, 1987</p> / digitalisering@umu

This thesis examines the link between airborne flux estimates of CO$ sb2$, sensible heat, and water vapor, and surface parameters retrieved by remote sensing. Chapter 1 analyses the relationship between surface temperature and vegetation indices, obtained from the Advanced Very High Resolution Radiometer on board of NOAA-9 and -10 satellites, and fluxes of sensible heat, latent heat, and CO$ sb2$, estimated from aircraft. Linear relationships between CO$ sb2$ and the Normalized Difference Vegetation Index (NDVI) or the Simple Ratio vegetation index (SR) are found on a daily basis, but a highly nonlinear relationship appears for the seasonal variation. Latent Heat fluxes showed the poorest correlations with surface parameters. A seasonal linear relationship appeared between sensible heat and NDVI. Local extreme flux values due to the intermittency of boundary layer dynamics largely contribute to lower the correlations; such variations are the reason for the difficulties in relating fluxes obtained from single overpasses and over short distances to fixed points at the surface. This problem is further examined in Chapter 2, in which conditional sampling of airborne flux estimates is used to characterize the turbulent structures that are carrying flux, and their link to the surface. The analysis confirms that few extreme events may carry a significant fraction of the flux. Missing or hitting one of these structures may translate into very large oscillations on the flux estimate that are often not directly coupled to surface characteristics. A much clearer surface 'signature' emerges when measurements are taken within the surface layer, since the reorganization of turbulent structures that takes place with increasing height will result in a merging of the signature that came from different sources at the surface. This helps to explain some of the poor correlations obtained in Chapter 1 and reinforces the need for a better understanding of the distributions of these tu

Submitted by Raniere Barreto (raniere.barros@ufvjm.edu.br) on 2018-05-07T17:53:28Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) rodrigo_silva_colares.pdf: 3761580 bytes, checksum: b009addae00984b9254b793f44de0488 (MD5) / Rejected by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br), reason: Verificar t?tulo. on 2018-05-14T18:41:07Z (GMT) / Submitted by Raniere Barreto (raniere.barros@ufvjm.edu.br) on 2018-05-15T17:59:40Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) rodrigo_silva_colares.pdf: 3761580 bytes, checksum: b009addae00984b9254b793f44de0488 (MD5) / Rejected by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br), reason: devolvendo. Aproveito para uma observa??o. Lan?ar o n?mero de p?ginas da ?ltima pag numerada. N?o considere a ficha. on 2018-05-15T19:04:17Z (GMT) / Submitted by Raniere Barreto (raniere.barros@ufvjm.edu.br) on 2018-10-26T19:20:22Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) rodrigo_silva_colares.pdf: 3761580 bytes, checksum: b009addae00984b9254b793f44de0488 (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2018-11-10T11:08:21Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) rodrigo_silva_colares.pdf: 3761580 bytes, checksum: b009addae00984b9254b793f44de0488 (MD5) / Made available in DSpace on 2018-11-10T11:08:21Z (GMT). No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) rodrigo_silva_colares.pdf: 3761580 bytes, checksum: b009addae00984b9254b793f44de0488 (MD5) Previous issue date: 2017 / Um bom projeto arquitet?nico deve considerar o conforto do usu?rio, sendo que um dos principais fatores que dificultam na execu??o do mesmo ? a posi??o de cada c?modo. Este problema ? relevante, considerando a posi??o do sol em rela??o ao terreno, sendo que parte da edifica??o ficar? posicionada com sua parede recebendo energia t?rmica no per?odo da tarde, gerando desconforto no ambiente. Este fato ? agravante em regi?es em que as altas temperaturas s?o comuns quase o ano todo. A redu??o do fluxo de calor para dentro da resid?ncia se torna fundamental, minimizando a utiliza??o de aparelhos que reduzem a temperatura. A pesquisa tem como objetivo determinar uma melhor configura??o para a alvenaria de veda??o, avaliando sua efici?ncia t?rmica. Ap?s os ensaios realizados, constatou-se que as paredes duplas com tijolos de 8 ou 9 furos, com ou sem EPS entre as camadas, melhoram de forma significativa o conforto t?rmico no interior das edifica??es. A configura??o com reboco de 2cm em ambos os lados apresentou melhor custo x benef?cio. / Disserta??o (Mestrado Profissional) ? Programa de P?s-Gradua??o em Tecnologia, Sa?de e Sociedade, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2017. / A good architectural design should regard the comfort of the user, since one of the main factors that hampers its execution is the position of each room. This problem is relevant, considering the position of the sun in relation to the terrain, since the building part will be positioned with its wall receiving thermal energy in the period of the afternoon, generating discomfort in the environment. This fact is aggravating in regions that high temperatures are common almost all year. Reducing the flow of heat into the home becomes essential, minimizing the use of equipments that decrease the temperature. The research aims to determine a better configuration for the mansory of the seal, evaluating it?s thermal efficiency. After the tests, it was verified that double walls with 8 or 9 hole-bricks, with or without EPS between the layers, significantly improve the thermal comfort inside the buildings. The configuration with 2 cm plaster on both sides showed better cost x benefit.

xvii, 189 p. ： ill. (some col.) / Low-dimensional electronic systems, systems that are restricted to single energy levels in at least one of the three spatial dimensions, have attracted considerable interest in the field of thermoelectric materials. At these scales, the ability to manipulate electronic energy levels offers a great deal of control over a device's thermopower, that is, its ability to generate a voltage due to a thermal gradient. In addition, low-dimensional devices offer increased control over phononic heat flow. Mesoscale geometry can also have a large impact on both electron and phonon dynamics. Effects such as ballistic transport in a two-dimensional electron gas structure can lead to the enhancement or attenuation of electron transmission probabilities in multi-terminal junctions. The first half of this dissertation investigates the transverse thermoelectric properties of a four-terminal ballistic junction containing a central symmetry-breaking scatterer. It is believed that the combined symmetry of the scatterer and junction is the key component to understanding non-linear and thermoelectric transport in these junctions. To this end, experimental investigations on this type of junction were carried out to demonstrate its ability to generate a transverse thermovoltage. To aid in interpreting the results, a multi-terminal scattering-matrix theory was developed that relates the junction's non-linear electronic properties to its thermoelectric properties. The possibility of a transverse thermoelectric device also motivated the first derivation of the transverse thermoelectric efficiency. This second half of this dissertation focuses on heat flow phenomena in InAs/InP heterostructure nanowires. In thermoelectric research, a phononic heat flow between thermal reservoirs is considered parasitic due to its minimal contribution to the electrical output. Recent experiments involving heterostructure nanowires have shown an unexpectedly large heat flow, which is attributed in this dissertation to an interplay between electron-phonon interaction and phononic heat flow. Using finite element modeling, the recent experimental findings have provided a means to probe the electron-phonon interaction in InAs nanowires. In the end, it is found that electron-phonon interaction is an important component in understanding heat flow at the nanoscale. This dissertation includes previously unpublished co-authored material. / Committee in charge: Dr. Richard Taylor， Chair； Dr. Heiner Linke， Advisor； Dr. David Cohen， Member； Dr. John Toner， Member； Dr. David Johnson， Outside Member

Les travaux menés dans cette thèse sont en lien avec les inégalités fonctionnelles et géométriques, dans le cadre continu et discret. En particulier, nous exploitons le principe de monotonie le long du flot de la chaleur, dont les conséquences ont été nombreuses en analyse, géométrie et probabilité depuis les travaux fondateurs de Bakry et Émery. Plus récemment, ce principe a été utilisé pour répondre à des questions d'informatiques théoriques via l'analyse des fonctions booléennes. Dans une première partie, nous présentons diverses inégalités à intégrales multiples et inégalités de type géométriques obtenues par monotonie le long du semi-groupe de la chaleur. Nous caractérisons, par la plupart d'entre elles, les cas d'égalités et mettons en évidence des phénomènes de rigidité dans le cas de variétés riemanniennes. En particulier nous étudions la rigidité pour le théorème de comparaison isopérimétrique de Bakry-Ledoux en utilisant leur preuve par flot de la chaleur. Cette preuve a été exploitée par Mossel et Neeman pour obtenir un résultat de stabilité robuste dans le cas gaussien. Nous reprenons cette preuve et nous la simplifions, en particulier en éliminant la plupart des arguments spécifiques au cas gaussien. Cela laisse espoir d'obtenir une version quantitative pour des mesures log-concaves plus générales ou sur les sphères euclidiennes de grandes dimensions. La deuxième partie est consacrée à l'analyse des fonctions booléennes. Le résultat principal de cette partie est l'extension d'un critère dû à Benjamini, Kalai et Schramm liant sensibilité au bruit et influences d'une fonction booléenne. Ce critère a été récemment étendu sur l'espace gaussien à travers le concept d'influences géométriques. En particulier, nous donnons une nouvelle preuve quantitative de ce résultat, basée sur des arguments de semi-groupes. Le résultat ainsi obtenu s'étend à des modèles de graphes de Schreier plus généraux que le cube ainsi qu'à des modèles continus autre que l'espace gaussien. En particulier, la version quantitative sur les tranches du cube booléen a des conséquences en théorie de la percolation. Dans une dernier chapitre, nous mettons en lien ce critère quantitatif pour donner une généralisation à des graphes produits du théorème "Junta" de Friedgut. / The general topic of this Ph.D thesis is functional and geometrical inequalities, in both continuous and discrete setting. In particular, we make use of the monotone property along the heat flow, which had led to important developments in analysis, geometry and probability since the pioneer work of Bakry and Émery. More recently, this principle has been used in the analysis of Boolean functions in view of application in theoretical computer science. In the first part, we present some multiple integrals inequalities and geometric type inequalities obtained by monotonicity along the heat flow. We characterize, for most of them, equality cases and we put forward rigidity phenomenon in the setting of Riemannian manifolds. In particular, we study rigidity for the Bakry-Ledoux isoperimetric comparison theorem using their semigroup proof. This proof has been exploited by Mossel and Neeman to derive robust dimension free bounds for the Gaussian isoperimetry. We simplify their proof an in particular remove most of Gaussian-specific parts. This gives hope to derive robust estimates to more general log-concave measures or on high dimensional Euclidean spheres. The second part is devoted to analysis of Boolean functions. The principal contribution in this field is the extension of a criterion of Benjamini, Kalai and Schramm linking noise sensitivity and influences of a Boolean function. Such a criterion has been extended recently in continuous setting via the concept of geometric influence. We give a new, semigroup, proof of a quantitative version of it previously established in the discrete cube and in the Gaussian space. This quantitative version generalizes both to various models of Schreier graphs and more general continuous spaces. In particular, the quantitative version over the slices of the Boolean cube has consequences in percolation theory. In the last chapter, we link this quantitative criterion with a generalization over graph products of the "Junta" theorem of Friedgut.

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

Résumé Les processus hydrothermaux affectent l'ensemble des domaines océaniques et contrôlent efficacement leur régime thermique. Cependant, les études de flux de chaleur à l'échelle globale conduisent à des interprétations parfois en contradiction avec les études locales. Il est donc essentiel de comparer les effets de l'hydrothermalisme dans différents contextes régionaux. Dans cette optique, nous avons étudié le rôle de l'hydrothermalisme sur le régime thermique d'un domaine océanique jeune (en Atlantique) et d'une marge continentale jeune (Sud Baléares). Pour cela, nous avons quantifié les transferts et pertes de chaleur et de matière en utilisant des traceurs thermiques (mesures du flux de chaleur) et des traceurs chimiques (analyse des fluides interstitiels). Le domaine océanique jeune se situe dans l'océan Atlantique sur le premier segment au sud de la faille transformante Oceanographer. Les faibles valeurs du flux de chaleur indiquent que les circulations hydrothermales, induites par les nombreux affleurements, extraient d'importantes quantités de chaleur de la croûte. La composition de l'eau interstitielle est similaire à l'eau de mer, indiquant un temps de résidence faible de l'eau dans le socle. Nous avons identifié que la rugosité du plancher océanique est un des paramètres majeurs qui contrôlent l'efficacité de ces circulations de fluides. Ce relief à petite échelle a été comparé à d'autres régions où l'efficacité des processus hydrothermaux avait préalablement été discutée. Nous en avons déduis une relation empirique qui relie la fraction du flux de chaleur à ce relief. Sur la marge Sud des Baléares, les processus hydrothermaux semblent plus restreints car leur impact thermique est plus local. Sur la pente continentale, des contrastes importants du flux de chaleur ont été mis en évidence. Ils suggèrent des circulations hydrothermales controlées par la présence de nombreux monts volcaniques. Cependant, la chimie des fluides reste proche de celle de l’eau de mer et ne permet pas de confirmer ces observations. En revanche, les processus hydrothermaux sont limités dans le bassin par les épais dépôts de sédiments. La chimie des fluides indique la présence de saumures résiduelles et leur simple diffusion vers la surface. Les valeurs du flux de chaleur sont perturbées par les contrastes de conductivité thermique induits par la présence de diapirs de sel ou du socle. Dans les deux zones d’étude, les circulations de fluides sont liées à la présence de structures basaltiques fracturées dont la perméabilité est supérieure de plusieurs ordres de grandeur à celle des sédiments alentours. La rugosité initiale du plancher océanique et le taux de sédimentation contrôlent la tranche d’âge durant laquelle la croûte reste connectée à l’océan. En revanche, les circulations sont rapidement inhibées sur les marges par les apports importants de sédiments venant du continent proche. Cette conclusion est contrebalancée par d’autres événements pouvant survenir sur les marges telles que le volcanisme ou la tectonique active. / Hydrothermal processes affect all oceanic domains therby controlling their thermal regime. At global scale, heat flow studies may lead to different interpretations than local studies. Comparing hydrothermal effects in different local contexts is essential to overcome this scale- issues. To do so, we studied the hydrothermal impact on the thermal regimes of a young oceanic domain (Atlantic Ocean) and a young margin (South Balearic). We quantified heat and matter transfers and heat losses with heat flow measurements and pore water chemical analyses. The young oceanic domain is situated on the first segment south of Oceanographer transform fault in the Atlantic Ocean. The low heat flow values indicate that hydrothermal circulations, conveyed by numerous outcrops, extract a lot of crustal heat. The composition of water in pores is similar to that of seawater. This points to a short residence time of water in the basement. We identified that the ruggedness of the seabed is one of the key parameters that control the fluid circulation efficiency. This small scale relief was compared to others regions where hydrothermal processes have already been debated. We deduced an empirical relation which links the fraction of the conductive heat flow to this relief. On the Southern Balearic margin, hydrothermal processes appear to be more limited because of their more local thermal impact. On the continental slope, great heat flow contrasts are highlighted. They suggest that hydrothermal circulation is controlled by numerous volcanic mounts. On one hand, pore fluid chemistry remains close to seawater composition and does not allow confirming these observations. On the other hand, hydrothermal processes in the basin are limited by thick sediment deposits and pore fluid chemistry indicates residual brines and their diffusion towards the surface. Heat flow values along the Southern Balearic margins are perturbed by thermal conductivity contrasts induced by salt diapirs or basement topography. In both study areas, fluid circulations are linked to fractured basaltic structures with a much larger permeability than the surrounding sediments. The seabed’s initial ruggedness and the sedimentation rate control the age range during which the crust is connected to ocean. Nevertheless, fluid circulations cease quickly due to important sediment flows from the nearby continent. This conclusion is partially offset by other events that may occur on the margins such as volcanism or active tectonic.

Some of the problems with today’s urban civilizations are the lack of green areas and that the cities are getting warmer and warmer. Building green roofs contributes to a reduced greenhouse effect, as plants have a cooling effect that reduces the heat generated in both houses and cities. The greenhouse effect is reduced by the fact that the plants on the roof reflect much more solar energy than a black ceiling, which instead absorbs the heat. The plants help to make the building more energy efficient. Green roofs also contribute to the emergence of new green areas in cities where the settlement has taken over the city. The purpose of the study has been to, from an energy perspective, examine the advantages and potential disadvantages of green roof energy performance in the subarctic climate. The study has been conducted by analyzing measured heat flow and temperature conditions during a winter season. The study was delimited to the green roof of Sjunde Huset in Kiruna, Norrbotten, Sweden. The research questions examined are the advantages and disadvantages of energy performance for green roofs, how does the energy performance vary for green roofs in cold climate during the season and what energy performance has the green roof under investigation in the subarctic climate. The study has been done through analysis of measurement data to see if the cooling effect from an energy perspective can be a disadvantage in a so-called subarctic climate. The analysis has also investigated whether the heat-insulating and heat-storing effect can be an advantage from an energy perspective in a so-called subarctic climate. The test period under review is from October 25, 2016 to January 4, 2017. The test period shows changes at different times. These times have been explored more closely. Collected measurement data has been analyzed using Excel chart against data for different weather conditions from SMHI. The different weather conditions are solar time, global radiation, wind speed and wind direction. Parameters that are also taken into account are polar night, night radiation, night cooling and snow conditions. The results show that green roofs are more beneficial in the subarctic climate from an energy perspective compared to black roofs. The green roof has lower temperature changes and heat flow than a traditional black roof. The internal temperature and heat flow of the green roof remain stable with minor changes during the winter period that is studied. The green roof has less temperature changes, heat flow and more stable indoor temperature than the black roof can depend, inter alia, on the thermal mass of the roof and the insulating capacity of the soil layer, which provides better thermal insulation. High wind velocities and low outdoor air temperatures can also be contributing factors to a cooling that causes slight changes in heat flow. Since the snow layer can function as an extra insulating layer and the test period only lasted until January 4, it would be interesting to see further studies where the entire winter season is analyzed. This is to see how the green roof behaves during a whole winter season, but also in the spring when large amounts of melt water can contribute to condensation that can affect heat flow. In the spring, large temperature differences can occur during day and night times that can affect heat flow through the green roof.

Numerical estimates of the ability of a green roof to reduce energy consumption in buildings are plagued by a lack of accuracy in thermal properties that are input to the model. An experimental study into the thermal conductivity at different temperatures and moisture contents was performed using four different commercially available substrates for green roofs. In the unfrozen state, as moisture content increased, thermal conductivity increased linearly. In the phase transition zone between +5 ºC and -10ºC, as temperature decreased, thermal conductivity increased sharply during the transition from water to ice. When the substrate was frozen, thermal conductivity varied exponentially with substrate moisture content prior to freezing. Power functions were found between thermal conductivity and temperature (when shifted up by +10.001ºC). Two equally sized, green roof test cells were constructed and tested to compare various roof configurations including a bare roof, varying media thickness for a green roof, and vegetation. The results show that compared with the bare roof, there is a 75% reduction in the interior temperature amplitude for the green roof with 150mm thick substrate. When a sedum mat was added, there’s a 20% reduction in the amplitude of the inner temperature as compared with the cell without sedum mat. / Graduate

In the first two chapters of this thesis, the novel method, developed by Mathews and Richards1, for predicting the thermal performance of buildings is introduced. The further enhancement and theoretical clarification of this method is the objective of this thesis. The method is based on a very simple thermo-flow network which models only the most important aspects of heat-flow in buildings. While Mathews and Richards based their network on analysis of the primary aspects of heat-flow in buildings, this thesis derives the simplified model by reduction from a comprehensive model. In this way, the assumptions and limitations is illuminated and the theoretical foundation of the method can be established. As a result of the investigation, a new simplified model with certain theoretical benefits is suggested. In later chapters, the method is extended and refined. Also, a new calculation procedure for finding solutions of the model is presented. In particular the method is extended to include multi-zone heat-flow, structural storage- and variable thermal systems. The new solution method is powerful, simple and efficient. This thesis contributes to the establishment of a viable tool for thermal analysis of buildings. / Dissertation (MEng)--University of Pretoria, 1990. / Mechanical and Aeronautical Engineering / unrestricted