This thesis is concerned with measuring the fabric thermal performance of houses. This is important because the evidence shows that predictions of performance, based upon a summation of expected elemental performance, are prone to significant inaccuracy and in-situ performance is invariably worse than expected the so-called performance gap . Accurate knowledge of the thermal performance of houses could cause a shift in the way that houses are built, retrofitted and managed. It would enable quality-assurance of newly-built and retrofitted houses, driving an improvement in the energy performance of the housing stock. The current barrier to achieving these benefits is that existing measurement methods are impractically invasive for use on a mass-scale. The aim of this research is to address this issue by developing non-invasive fabric thermal performance measurement methods for houses. The co-heating test is currently the most used method for measuring whole-house fabric thermal performance; it is used to measure the Heat Loss Coefficient (HLC) of a house, which is a measure of the rate of heat loss with units of Watts per degree Kelvin. It has been used extensively in a research context, but its more widespread use has been limited. This is due to a lack of confidence in the accuracy of its results and the test s invasiveness (the house must be vacant for two weeks during testing, which has so far been limited to the winter months, and testing cannot be carried out in newly-built houses for a period of approximately one year due to the drying out period). To build confidence in the results of co-heating testing, the precision with which test results can be reported was determined by the combination of a sensitivity analysis to quantify measurement errors, and an analysis of the reproducibility of the test. Reproducibility refers to the precision of a measurement when test results are obtained in different locations, with different operators and equipment. The analysis of the reproducibility of the test was based upon a direct comparison of seven co-heating tests carried out by different teams in a single building. This is the first such analysis and therefore provides a uniquely powerful analysis of the co-heating test. The reproducibility and sensitivity analyses showed that, provided best practise data collection and analysis methods are followed, the HLC measured by a co-heating test can be reported with an uncertainty of ± 10%. The sensitivity analysis identified solar heat gains as the largest source of measurement error in co-heating tests. In response, a new approach for co-heating data collection and analysis, called the facade solar gain estimation method, has been developed and successfully demonstrated. This method offers a clear advancement upon existing analysis methods, which were shown to be prone to inaccuracy due to inappropriate statistical assumptions. The facade method allowed co-heating tests to be carried out with accuracy during the summer months, which has not previously been considered feasible. The demonstration of the facade method included a direct comparison against other reported methods for estimating solar gains. The comparison was carried out for co-heating tests undertaken in three buildings, with testing taking place in different seasons (winter, summer, and spring or autumn) in each case. This comparison provides a unique analysis of the ability of the different solar gain estimation methods to return accurate measurements of a house s HLC in a wide variety of weather conditions. Building on these results, a testing method was developed: the Loughborough In-Use Heat Balance (LIUHB). The LIUHB is a non-invasive measurement method, designed and tested in this study, which can measure the HLC of a house with an accuracy of ± 15% while it is occupied and used as normal. Measurements of energy consumption and internal temperature are discreetly collected over a period of three weeks, and combined with data collected at a local weather station to inform an energy balance, from which the HLC is calculated. This low impact monitoring approach removes the barriers to fabric thermal performance testing on a mass scale. The LIUHB has been successfully demonstrated in several comparative trials versus a baseline measurement provided by the co-heating test. The trials have included the application of extreme examples of synthetic occupancy conditions, testing in an occupied house, and quantification of the effects of a retrofit. Subject to further validation, the LIUHB has the potential to deliver many of the benefits associated with mass-scale measurement and quality assurance of housing performance.

Five projects improve understanding of how to use PCM to reduce building cooling energy. Firstly, a post-installation energy-audit of an active cooling system with PCM tank revealed an energy cost of 10.6% of total cooling energy, as compared to an identical tankless system, because PCM under%cooling prevented heat rejection at night. Secondly, development of a new taxonomy for PCM cooling systems allowed reclassification of all systems and identified under-exploited types. Novel concept designs were generated that employ movable PCM units and insulation. Thirdly, aspects of the generated designs were tested in a passive PCM sail design, installed in an occupied office. Radiant heat transfer, external heat discharge and narrow phase transition zone all improved performance. Fourthly, passive PCM product tests were conducted in a 4.2 m3 thermal test cell in which two types of ceiling tile, with 50 and 70% microencapsulated PCM content, and paraffin/copolymer composite wallboards yielded peak temperature reductions of 3.8, 4.4 and 5.2 °C, respectively, and peak temperature reductions per unit PCM mass of 0.28, 0.34 and 0.14 °C/kg, respectively. Heat discharge of RACUS tiles was more effective due to their non-integration into the building fabric. Conclusions of preceding chapters informed the design of a new system composed of an array of finned aluminium tubes, containing paraffin (melt temperature 19.79 °C, latent heat 159.75 kJ/kg) located below the ceiling. Passive cooling and heat discharge is prioritised but a chilled water loop ensures temperature control on hotter days (water circulated at 13 °C) and heat discharge on hotter nights (water circulated at 10 °C). Test cell results showed similar passive performance to the ceiling tiles and wallboards, effective active temperature control (constant 24.6˚C air temperature) and successful passive and active heat discharge. A dynamic heat balance model with an IES% generated UK office’s annual cooling load and PCM temperature%enthalpy functions predicted annual energy savings of 34%.

Approximately 30% of the UK s housing stock is comprised of older, solid wall buildings. Solid walls have no cavity and were built without insulation; therefore these buildings have high heat loss, can be uncomfortable for occupants throughout the winter and require an above-average amount of energy to heat. Solid wall buildings can be made more energy efficient by retrofitting internal wall insulation (IWI). However, there is little empirical evidence on how much energy can be saved by insulating solid wall buildings and there are concerns that internal wall insulation could lead to overheating in the summer. This thesis reports measured results obtained from a unique facility comprised of a matched pair of unoccupied, solid wall, semi-detached houses. In the winter of 2015 one house of the pair was fitted with internal wall insulation then both houses had their thermal performance measured to see how differently they behaved. Measuring the thermal performance was the process of measuring the wall U-values, the whole house heat transfer coefficient and the whole house airtightness of the original and insulated houses. Both houses were then monitored in the winter of 2015, monitoring was the process of measuring the houses energy demand while using synthetic occupancy to create normal occupancy conditions. In the summer of 2015 indoor temperatures were monitored in the houses to assess overheating. The monitoring was done firstly to see how differently an insulated and an uninsulated house perform under normal operating conditions: with the blinds open through the day and the windows closed. Secondly, a mitigation strategy was applied to reduce high indoor operative temperatures in the houses, which involved closing the blinds in the day to reduce solar gains and opening the windows at night to purge warm air from the houses. The original solid walls were measured to have U-values of 1.72 W/m2K, while with internal wall insulation the walls had U-values of 0.21 W/m2K, a reduction of 88%. The house without IWI had a heat transfer coefficient of 238 W/K; this was reduced by 39% to 144 W/K by installing IWI. The monitored data from winter was extrapolated into yearly energy demand; the internally insulated house used 52% less gas than before retrofit. The measured U-values, whole house heat loss and energy demand were all compared to those produced from RdSAP models. The house was found to be more energy efficient than expected in its original state and to continue to use less energy than modelled once insulated. This has important implications for potential carbon savings and calculating pay-back times for retrofit measures. In summer, operative temperatures in the living room and main bedroom were observed to be higher, by 2.2 oC and 1.5 oC respectively, in the internally insulated house in comparison to the uninsulated house. Both of these rooms overheated according to CIBSE TM52 criteria; however the tests were conducted during an exceptionally warm period of weather. With the simple mitigation strategy applied the indoor operative temperature in the internally insulated house was reduced to a similar level as observed in the uninsulated house. This demonstrates that any increased overheating risk due to the installation of internal wall insulation can be mitigated through the use of simple, low cost mitigation measures. This research contributes field-measured evidence gathered under realistic controlled conditions to show that internal wall insulation can significantly reduce the energy demand of a solid wall house; this in turn can reduce greenhouse gas emissions and could help alleviate fuel poverty. Further to this it has been demonstrated that in this archetype and location IWI would cause overheating only in unusually hot weather and that indoor temperatures can be reduced to those found in an uninsulated house through the use of a simple and low cost mitigation strategy. It is concluded that IWI can provide a comfortable indoor environment, and that overheating should not be considered a barrier to the uptake of IWI in the UK.

The thesis consists of general characteristics, list of notations, introduction, four main chapters, general conclusions, 56 pictures, 2 tables and list of references. The total scope of the dissertation is 106 pages.

This dissertation thesis is focused on the study of simultaneous transport of heat and moisture in building components. First, the introduction briefly summarises current international state of the art in assessment and evaluation of building components focused on moisture. Besides description of methodological approaches and analysis of differences between them, the approaches are modelled using examples which help to identify their properties and explain the application framework of the methods. These examples do not only illustrate the procedures; they also indicate their limits and identify the pitfalls of models’ application in comparison with each other. Next, the thesis includes basic introduction to material parameters necessary in numerical modelling. Moreover, solutions to questions from the assignment are discussed from the point of view of the theory of heat and moisture transport. To fulfil the thesis’ objectives, theoretical analysis and calculations were implemented. Calculations were carried out not only by well-known methods, but also using an own-developed complex algorithm which implements simultaneous heat and moisture transport modelling based on finite element methods and which allows to implement nonlinear behaviour of material properties. Furthermore, the thesis contains description of and results from two experiments. A brief description of an electronic device developed and used for the experiments is included. Experimental results are confronted with both simplified and advanced theoretical models. At last the thesis concludes with discussion of acquired findings, brief summary of potential contribution of this work to the field of building science and engineering practice, and indication of the directions for further development.

No description available.

No description available.

The diploma thesis on the topic Kindergarten is processed in the form of project documentation for the implementation of the building. The building is designed to plot 12288 in the cadastral Vsetín. It is a new kindergarten with two floors. The building is brick, It is covered by single-layer flat roof. The building contains three classes for a total of 75 children, also has its own kitchen and pottery.

Over the last two centuries, there has been a continual evolution of how occupied rooms are heated, with inventors competing to design new heating devices. In particular, there is a wide range of convector types, which vary in shape, size, design, material, operating medium and application. With approximately 190 million convectors installed in the UK alone, the question arises regarding the dependencies on the efficiency of heat distribution through convector-induced filling flows. A standard approach to evaluate convector performance is based on the convector strength only, the implication being the stronger the convector the better the performance. This work has gone beyond the limits of a stereotypical assessment in pursuit of answers regarding the physics of convector-induced filling and a new objective method to evaluate the efficiency of this transient process. The ultimate goal has been to provide a deep understanding of filling and stratification induced by a convector, in order to heat rooms rapidly and effectively. An experimental facility has been designed that approximates dynamic similarity between the experimental set-up and a real-life room with a convector. In the experiments, a rectangular sectioned water tank represents a room and a saline source rectangular sectioned panel with sintered side walls provides a convector representation. Experiments have been performed in water with a saline solution to ensure high Rayleigh numbers. Diagnostic techniques involve a combination of a shadowgraph method, a dye-attenuation method, direct salinity measurements and a new application of Particle Image Velocimetry (PIV). Interesting insight into convector-induced buoyancy-driven flows has been gained. As a result, new guidelines aimed at heating rooms more rapidly and effectively have been proposed. The key outcome that can be immediately applied is that, for a given convector strength, heat distribution with height can be improved by adjusting the convector position. For instance, faster filling leading to more uniform heat distribution occurs in rooms with convectors detached from side walls, due to large-scale mixing flows in the early period of filling. Also shorter convectors relative to the room height, positioned close to the floor level, promote faster and more uniform filling. An attempt to describe the transient filling has been made and to do so statistical methods, application specific, have been developed. As a result, the empirical equations describing both the filling rates in different stages of filling and the development of stratification have been derived, which rank the governing parameters, based on their importance, as either dominant or subordinate. Two dominant parameters governing filling flows are the non-dimensional accumulation parameter B and the Rayleigh number ΔRa, which are related to the convector strength. The impact of these two parameters is constant throughout the process. The parameters accounting for the system geometry and filling time (T) are subordinate parameters. Their impact, visible in the early period, decreases as filling continues.

Notre investigation porte sur la simulation numérique des échanges thermo-convectifs dans un canal vertical ouvert à flux imposé. Cette étude rentre dans le cadre des recherches sur le rafraîchissement passif des composants PV intégrés au bâtiment. À cet effet, un code numérique en Différences Finies est utilisé pour résoudre les équations de Navier-Stokes et simuler la convection naturelle dans un canal. Ce problème reste difficile à résoudre parce que l'écriture des conditions aux limites d'entrée et de sortie reste un problème ouvert. Notre travail consiste d'abord en étude des différentes conditions aux limites pour le benchmark numérique AMETH. Les travaux réalisés ont permis de faire un premier choix sur les conditions aux limites. L'étude s'oriente ensuite sur la qualification et la quantification numériques et expérimentales pour deux fluides : l'air (convection-rayonnement) et l'eau (convection pure). Les résultats numériques/expérimentaux ont été comparés et les discordances ont été analysées. Plusieurs aspects phénoménologiques (rayonnement entre surfaces, variation des propriétés thermo-physiques, variation du nombre de Prandtl) ont été abordés afin de caractériser leurs influences respectives sur l'écoulement et le transfert thermique. Enfin, dans le but d'apporter des éléments de réponses sur les conditions aux limites dynamiques, nous avons simulé la convection naturelle d'un canal dans une cavité et tenté une modélisation. / The present investigation deals with natural convection flow in a vertical open-ended channel with wall constant heat flux. This study falls under the framework of research on passive cooling of building integrated PV components. For this purpose, a numerical code developed with Finite Differences scheme is used to solve Navier-Stokes equations and simulate the natural convection in a channel. This problem is difficult to solve because the writing of inlet/outlet boundary conditions remains an open problem. First, our work consists of studying different boundary conditions for the the numerical benchmark AMETH. The work carried out has enabled a first choice of boundary conditions. The study then focuses on numerical and experimental quantification and qualification for two fluids : air ( convection - radiation) and water ( pure convection) . Experimental and numerical results were compared and discrepancies were analyzed. Several phenomenological aspects ( surface radiation, thermophysical properties variation, Prandtl number variation ) were discussed in order to characterize their influence on flow and heat transfer. Finally, in order to provide some answers on dynamical boundary conditions, we simulated natural convection of a channel inside a cavity and tried a modeling.