In 2009 the Brazilian government committed to support the construction of nearly 24 million new dwellings by 2022 through its housing programme Minha Casa, Minha Vida (My House, My Life). The initiative aims to tackle the housing shortfall of 5.546 million residential units and the 10.948 million units that are considered inadequate dwellings with poor living conditions. The potential economic, social and environmental impact of such large initiative is vast and consequently it is essential that the new dwellings are planned, designed and built to meet high levels of energy efficiency and thermal comfort. The ‘Fabric First’ is widely recognised as a design approach with great potential to deliver energy efficient and comfortable housing in a variety of different climates. Its principles have already been successfully incorporated in many buildings across European countries and elsewhere. Despite its success, research to date shows that the application of this approach has not been explored yet in the Brazilian context. In this work, ways of improving the thermal comfort and performance of Brazilian mass housing in three cities in southern Brazil (Curitiba, São Paulo and Porto Alegre) through the Fabric First principles were explored. The research was developed through sensitivity analyses of key envelope parameters and case studies. The sensitivity analysis was carried out in order to identify the best performance and the most cost-effective building envelope combination, using a simplified affordable Brazilian housing typology model that had its properties varied. A case study based on a generic representative model and a real optimised case study of typical 1-floor 2-bedroom mass housing typology were evaluated through computational thermal simulations and monitored data. The results of the sensitivity analyses were then used to inform the case studies performance analyses, developed in parallel to a cost analysis. Key findings from this study revealed that typical Brazilian building envelopes underperformed by up to 65% compared to super-insulated envelopes in terms of thermal comfort. In the real case studied this could represent up to 75% less thermal comfort. However, the additional costs of a super-insulated envelope showed to be 56-66% higher than the typical Brazilian envelope, with a payback period nearing the lifespan of the houses. In addition, it has been shown that relatively small improvements in the current building envelope could impact the upfront costs by only 6-12% but result in comfort improvement of about 45% against typical levels. These small improvements appear to be more suited to the cultural and economic Brazilian context and therefore are recommended as the best way forward.

No description available.

No description available.

An emerging trend in the building services industry is the installation of passive deaerators on the flow line of domestic wet central heating systems. To date, no data and theoretical models predicting the two-phase flow characteristics in domestic wet central heating systems are available in the open literature. This gap in literature has prevented essential design improvements to passive deaerators thus impeding the efficiency enhancement of such devices. Hence, the current study is aimed at assisting designers of deaeration devices by providing fundamental data and model correlations with respect to the two-phase flow characteristics typical in a wet domestic central heating system. For this purpose an experimental research project was adopted and several studies were carried out, including; (1) a comprehensive review to understand the background of the phenomena, (2) the design and construction of an experimental test rig to conduct the necessary investigations into the phenomenon of two-phase flow in domestic wet central heating systems, (3) the development of a reliable image capture and analysis technique, (4) the completion of a number of experiments to investigate typical bubble sizes, volumetric void fractions, bubble distributions and nucleation and dissolution rates and (5) the correlation of the data gathered as part of the present study with existing bubble size, nucleation and dissolution prediction models. This research has, for the first time, provided an in depth analysis into two-phase flow characteristics in wet domestic central heating systems through the use of a high speed camera and image analysis techniques. The two-phase phenomenon finds its origins in high dissolved gas concentrations present in the water flowing through the closed loop system, thus resulting in super saturation conditions at the primary heat exchange wall conditions. Bubble sizes at the boiler flow line were found to be dependent on the bulk fluid velocity, heat flux and pressure, with a measured mean diameter in the range of 0.13 mm to 0.39 mm. The Winterton (1972a) force balance model for bubble size prediction was in reasonable agreement with the experimental results. This model was further improved through the correlation of our data with the inclusion of dimensionless groups. Bubble nucleation rates have been calculated in the range of 0.3 to 4 bubbles / cm2 s with total system bubble production rates measured in the range of 784 to 6920 bubbles per second. Bubble nucleation rates have been calculated through the consideration of the heat exchanger surface under super saturation conditions. A correlation for the model by Hepworth et al. (2003) for nonclassical heterogeneous nucleation is proposed based on the experimental data gathered during the present study. Experimental results have shown dissolution rates for the bubble size ratio in the range of 0.4 to 12 % per second with system conditions. A modification of the model developed by Epstein and Plesset (1950) for stationary bubble dissolution is proposed with the inclusion of the Sherwood number to capture the effects of turbulent diffusion. The volumetric void fraction distribution in vertical pipes was found to be quasi-homogenous across the pipe section while being strongly dependent on gravitational and turbulence effects in horizontal pipe bubbly flow. A CFD simulation predicted the volumetric void fraction distribution with reasonable accuracy.

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.

Αντικείμενο αυτής της διπλωματικής εργασίας είναι η ανάλυση των κύριων τεχνικών εξοικονόμησης ενέργειας που βρίσκουν εφαρμογή στο κτιριακό κέλυφος και τα ενεργειακά συστήματα τόσο των δημόσιων χώρων, όσο και των χώρων παραγωγής, η παράθεση του τρέχοντος σχετικού νομοθετικού πλαισίου, η μελέτη της ενεργειακής συμπεριφοράς κάποιου υφιστάμενου κτιρίου και η αναβάθμιση αυτής με την εφαρμογή κατάλληλων τεχνικών εξοικονόμησης ενέργειας. / The main purpose of this diploma is to analyse the energy saving measures in public buildings and industries.

Double skin façades (DSFs) are gaining recognition as a technology that, while giving a modern transparent appearance to buildings, have the capability to moderate the indoor thermal conditions and the potential to reduce energy demands. A typical DSF consists of an additional fully glazed external skin installed over the conventional building façade forming an air cavity in which sunshade devices are often installed to prevent overheating in the internal rooms. The majority of the existing studies on DSF are based on air-conditioned models under temperate climate conditions, where most DSFs are implemented. However, developments in warmer climate countries such as Brazil are also considering the application of this technology as a solution to improve thermal performance in buildings. Therefore, investigations to understand the DSF thermal and airflow processes and implication of its use in naturally ventilated buildings under such climates are needed. The aim of this study is to determine the thermal performance of office buildings with DSF under Brazilian climate conditions. Firstly, the key parameters affecting the thermal performance of buildings with DSF are identified through critical literature reviews. Using an office building as a reference model, computational thermal dynamic simulations are performed to demonstrate the influence of each individual key parameter on the building‘s thermal behaviour. From the findings of the parametric analysis, optimized models that utilise a combination of solutions to maximize the building thermal performance are developed and analysed. Finally, acceptable thermal comfort levels of the optimized model in different Brazilian climatic regions and periods of the year are determined. This study evaluated the key parameters affecting the thermal performance of buildings with DSF, including: the significance of material selections in design solutions to maximize airflow through the building; the prevention of unintentional reverse flow on the upper floors and maintenance of balanced airflow rates across all floors; the impact of solar incidence and wind conditions on the DSF‘s thermal performance. Results from the simulations of the optimized model under different bioclimatic zones of Brazil indicated that in most parts of the country the thermal comfort acceptance levels are as low as 60%, especially in the hotter areas of centre west regions, coastal areas and north of the country. The outcomes of this research provide insight and understanding on the functioning of the DSF in naturally ventilated buildings in warm and hot climates. DSFs in naturally ventilated buildings under Brazilian climates generally presented lower thermal acceptability when compared to single skin models due to the high outside temperatures and the airflow resistance caused by the application of the second skin. Their application will therefore not have direct benefit to the thermal performance.

First, this research has attempted to identify the underlying reasons for high Chinese family cooking energy consumption. Second, this research has tried to identify ways of reducing Chinese kitchen cooking fume pollution. The literature review indicated that, although cooking energy takes one of the largest proportions of residential building energy consumption, previous studies in this area have not been enough. The published knowledge found indicates that urban residential buildings takes 1/4 of the national building energy consumption (excluding heating). This portion has grown continuously since 2001 in terms of energy consumption intensity (kgce/m2). Among household energy (excluding heating), cooking, home appliances and lighting are the three largest energy end users. Although the increase in cooking energy is low, partially attributed to wide adaptation to gas cooking fuel instead of coal fuel in China, it still takes the largest household energy consumption: 31% in 2011. Many research papers report different results based on field measurements of household energy end users, some of which show conflicting results. However, the literature review has confirmed that in China cooking energy consumes the second-largest amount of household energy after space heating. The literature review also pointed out that, although compared with Western counterparts, Chinese residential buildings consume less national energy, cooking takes a large percentage of household energy. A further literature review showed little valuable information underpinning the reasons for high cooking energy use in Chinese households. Some overseas research papers give hints regarding cooking energy and cooking techniques, cookware, and occupant behaviour. However, the difference in food culture traditions has led to a greater difference between Western and Chinese cooking techniques. Compared with Western countries, Chinese hot dishes require a greater number of cooking techniques. In order to find out more details of cooking energy and fume generation in real Chinese home kitchen conditions, the author used a series of research methodologies to measure and test home energy and cooking fume concentration. The results reconfirm that cooking energy is the second-largest home energy end user after space heating, along with other findings. These other findings include: • The four largest energy end users in northern Chinese households are space heating, cooking, hot water and entertainment. • Hot water, lighting and entertainment energy consumption have clear seasonal characteristics i.e., daily consumption is low in summer and high in winter. This is because of the colder weather in winter (demanding more energy to heat water) and longer nights in winter (with a longer indoor entertainment time and a greater requirement for lighting in the evening). • Daily cooking energy consumption in a given family is almost fixed, although the difference between different families is large. This could lead to further study on the underlying reasons for the difference between families. The most important finding in the research is the discovery of the relationship between home cooking energy and family life cycle. A strong relation was observed between these two factors. This was confirmed by the measurement of the test families as well as the survey of 70 random selected families. The relation is, therefore, denoted as the CookEUI (cooking energy use intensity) of the different family life cycles. Following the data analysis and survey, it was also found that the cooking energy for a certain family life cycle was constant, i.e., locked in an FLC stage until the stage changed. Finally, a database was built into the IES energy simulation using figures found in the research. This represents significant progress in home energy study. Before discovering cooking EUI, cooking energy in most pieces of energy simulation software was treated as a process load with a constant figure. A literature review of a large number of research papers concluded that cooking fumes have an adverse impact on people’s health. In China, a typical housewife spends about 4 hours in the kitchen every day, preparing and cooking meals. A comfortable and healthy cooking environment is critical for cooks’ health. It was also found that COF emissions in Western and Chinese kitchens differed largely in mass concentration. Cooking method, cooking oil and cooking temperature all contribute to the difference. Many other researchers have investigated the details of hood systems and their construction features in order to understand their efficiency in removing cooking fumes. However, most of the research has been based on commercial kitchen application. There is very little research on home kitchen hood efficiency. Research also points out that natural ventilation in the kitchen space has a certain amount of influence on the capture efficiency of an exhaust system. For example, opening the door is more efficient than opening a window. In this research, the measurements of kitchen PM2.5 and PM10 were carried out in real home kitchen cooking conditions. The relation between PM2.5 and PM10 emissions and different Chinese cooking methods was measured. It was found that deep frying and stir frying discharged the most PM2.5, while boiling emitted the least. A typical PM2.5 discharging pattern in Chinese cooking was observed. The pattern showed a sharp increase in PM2.5 concentration in the beginning at breath level with a drop afterwards because of the using up of cooking oil or the rising of water steam to a higher level. A small sub-surge was observed after the first selection because the downward flow of cold air brought high-level PM2.5 down to breath level. A very interesting finding observed when using tracer gas to measure kitchen cooking hood efficiency was the large difference between the airflow rate listed on the kitchen fume hood nameplate and the airflow rate measured in real kitchen conditions. On the nameplate of the cooking hood, airflow was rated as 800 m3/h at medium speed, while in the tracer gas testing the flow rate was a maximum of 175 m3/h when all the kitchen windows and the door were open. This finding reinforces the experiment conclusion by the Lawrence Berkeley National Laboratory for the seven representative devices they tested, whereby, according to Chen (2012), the capture efficiency varied from less than 15% to more than 98%. Identifying the airborne moving characteristics of PM2.5 can be used to help redesign ventilation systems for Chinese home kitchens. The traditional way of enhancing cooking fume removal efficiency is to increase the fan discharge pressure head. This leads to increased energy consumption. It also has less effect on removing PM2.5 particles, since, unlike PM10, PM2.5 is affected by airflow rate more significantly than air velocity. The proposed new ventilation system is intended to treat PM2.5 and PM10 separately. PM10 will be removed by the filter in recirculation devices and PM2.5 will be exhausted by a direct venting fan with replacement air. In this way, less energy is used and the system is more efficient at removing kitchen PM2.5.

Heating and cooling account nearly 60% of world total energy consumption and highly depending of conventional energy sources generated by fossils fuels. As the scarcity of oil reserves becomes the jargon issues in all part of the world today, researchers have to look into a robust investigation on finding the alternative energy to alleviate the dependency of conventional energy. Furthermore, if the phenomenon of using fossil fuel remain as the primary energy sources, it would affect adversely on the greenhouse gas emission. In 2008, The Climate Change Act by the UK Government had targeted that 34% cut in 1990 greenhouse gas emissions by 2020 and, at least, an 80% cut in emissions by 2050. Therefore, to achieve this target, more low carbon technology needed to realise the future reduction of emission. Renewable energy technologies such as solar, wind, geothermal and such thought to become the solution to reducing the demand for conventional energy. However, their instability considered as problematic for future energy demand. Thus, a more efficient management of energy demand, coupled with efficient energy storage systems is required. The aim of this study is to develop novel Thermochemical Heat Storage system (THSS) using off-peak power and renewable sources to minimise energy demands from fossil fuels and reducing GHG emissions. Thus, this could be achieved by developed and constructed a unique adsorption heat pipe using a high energy storage density of the nanocomposite Thermochemical material. Other than that, this unique adsorption heat pipe was integrated with a heat-pump circuit for desorption process. In this study, a Novel Thermochemical Heat Storage has been theoretically model, built and tested on a lab scale and a domestic-scale prototype. The chosen Thermochemical Material (Vermiculite + CaCl2) reacting with pure water vapour operates within a closed system. Other than that, result from thermal analysis shown that Vermiculite + CaCl2 could attain higher heat storage capacity of 374 kJ/kg. The heat storage system of this work based on reversible thermochemical reactions, such as adsorption and desorption of composite Thermochemical materials which exhibits very high energy storage density (up to 364 kWh·m3 of material storage). The small scale experimental investigation has found this THSS has the maximum adsorption temperature of 45.07°C to 71.12°C with the corresponding Coefficient of Performance (COP) of 0.53 to 1.34. Another investigation on Solar Heat Solar collector (SHSC) has carried out numerically and experimentally. The numerical study predicted that the temperature lift achieved at 42°C of using 10m2 of the solar collector. Hence, this SHSC has shown the possibility of integrating the TCM (Thermochemical material) with solar thermal energy. Lastly, a domestic scale THSS has revealed that the highest temperature uplift from the adsorption process at 57°C. The economic analysis of a domestic scale THSS has shown that this system will receive payback in 7.5 years with the internal rate of return (IRR) 15.25%. Furthermore, emission analysis demonstrated that this system would reduce 34% of CO2 in 20 years of its lifespans.

Concerns over sustainability in the built environment have resulted in continuous efforts to improve the performance of window system or glazed façade and hence indoor comfort and building energy conservation. An innovative façade system where parallel transparent/translucent plastic slats are sandwiched between glass panes to form a Parallel Slat Transparent Insulation Material (PS-TIM) is proposed as a strategy to effectively reduce heat transfer between the panes of a double glazed window, while maintaining access to daylight. A holistic investigation of the window system with PS- TIMs is conducted in terms of thermal and optical properties, as well as detailed daylight and energy performance predictions of applying PS-TIMs in buildings. Firstly, an experimental investigation is undertaken in a large climate chamber, and the measurement results were used to validate a two-dimensional Computational Fluid Dynamics (CFD) model. Secondly, the validated 2D CFD model is used to solve the dynamic thermal properties of different configurations of PS-TIMs under various environmental conditions. The optical properties (i.e. Bidirectional Scattering Distribution Function (BSDF)) of PS-TIMs are obtained via a ray-tracing technique based on the structures’ geometries and the material optical characteristics of the interstitial structure. The detailed annual daylight performance in different climates and building orientations are predicted using RADIANCE. Finally, the optical and thermal properties obtained from the previous fundamental models are applied in EnergyPlus to predict the energy performance (i.e. heating, cooling and lighting energy consumption) of applying PS-TIMs in buildings in different climates. The investigation results provide a better understanding of the benefits of PS-TIM in terms of energy saving and daylight comfort improvement, as well as offer some tentative suggestions as to how architects and engineers might apply PS-TIM to window system or glazed façade.