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The level of automation is one of the central issues in designing control systems. Occupant attitudes towards different levels of automation in domestic control systems were studied using a qualitative interview method. The following systems were considered: (1) control of indoor thermal environment, (2) peak load management, and (3) own energy production. For each system, four solutions representing different levels of automation were created. The interviewees gave comments on the solutions and chose the alternatives they preferred. The results show that decisions on the level of automation should be made carefully, taking account of the special qualities of each system without neglecting the individual differences between users. Full automation is not suitable for systems that considerably affect indoor environmental comfort. The interviews revealed a large amount of mistrust towards automation. An important question is how to improve the level of trust between the occupants and automation, i.e. how to make the occupants trust the automation in cases where better results would be gained through the utilisation of automation. The following system characteristics may potentially improve the level of trust: (1) carefully chosen level of automation, (2) predictability, transparency and feedback, (3) simplicity and usability and (4) suitability for everyday life.

Abstract A strong correlation exists between occupant behaviour and space heating energy use. In particular, the occupancy status (e.g., daytime absence) is known to have a significant influence on residential heating load profiles, as well as on cumulative heating energy consumption. In the literature, many occupancy models have been utilised to predict occupancy profiles of individual dwellings as part of the larger residential building stock. However, none of the existing models consider diversity associated with occupancy-integrated archetypes to generate high-temporal resolution heating load profiles. The current paper uses Time Use Survey (TUS) data to develop a high-temporal resolution residential building occupancy model. The key feature of the proposed model, implemented using MATLAB, is the ability to generate stochastic occupancy time-series data for national population subgroups characterised by specific occupancy profiles. It is shown that the results are capable of closely approximating data available from TUS. The developed model can be applied to improve the quality of modelled high-temporal resolution heating load profiles for generic building stock characterised by population subgroups represented by different occupancy-integrated archetypes. A case study is performed on a building stock sample located in London, UK. The developed occupancy model has been implemented in MATLAB and is available for download.

Abstract Energy performance of buildings generally assesses the energy consumption of buildings such as heating, domestic heat water, ventilation systems, etc. However, this approach is based on the first law of thermodynamics and considers only the quantity of energy used without considering its ‘quality’ and leads to a lack of information about the energy conversion processes. This is particularly true in the new low-energy buildings where sometimes high temperatures sources are used to meet low-temperature needs. The exergy analysis of a system, based on first and second thermodynamic laws, can be used to overcome this. In this work, it is proposed to compare the energy and the exergy consumption and the related CO2 emissions of several kinds of buildings to determine the best systems in terms of energy and exergy needs. The energy demand calculations are performed using the official software available in Belgium and some assumptions are implemented to consider the exergy approach. As exergy calculations require a reference state, some different climatic conditions are also investigated. Finally, some conclusions are discussed to rank the sources of energy and their related exergy losses.

Abstract This paper studies the application of spent mushrooms compost (SMC), as a new additive to produce bricks with better insulation and in a more sustainable way. The aim is to determine how SMC adding varies properties of fired clay bricks (FCBs), specially the thermal behavior, and whether it is a viable solution for recycling SMC. Clay was mixed with different percentages of SMC (0–17 wt.%) and formed by pressing. Samples were fired at the facilities of the partner's factory up to 950 °C. The influence of SMC on FCBs was related to its thermal conductivity (TC), compressive strength (CS), water absorption (WA), bulk density (BD), linear shrinkage (LS), apparent porosity (AP) and weight losses during firing (WL). As a result, a blend of clay with up to 17% SMC, limited by minimal CS and WA, may be used for masonry works with an enhancement on thermal behavior. Addition of 17% of SMC leads to a 26.17% decreasing in TC compare to those without SMC, achieving a minimum TC of 0.55 W/m K. This implies a reduction of 10% on the equivalent thermal transmittance, that means a better insulation of the buildings and thus this is an important energy saving.

Abstract Heating, ventilation, and air conditioning systems help maintain the appropriate level of thermal comfort and air quality in buildings. To this end, the energy supply of these systems must be guaranteed. However, continuous efforts are required to improve the energy efficiency of this system and reduce greenhouse gas emissions. In the zero-emission building approach, the use of thermoelectric devices has been proposed to meet the heating/cooling needs in the building and help in flexibly changing the operating conditions according to the user's needs. In this study, an experimental setup was developed consisting of a multipurpose thermoelectric system that is directly powered by a solar photovoltaic panel. The heating mode was designed for space heating, whereas the cooling mode was tailored to an adiabatic box that could cool food and beverages. The results of this study will facilitate the practical use of this device in the future by directly connecting the thermoelectric system to the room and evaluating the response of the system to temperature changes requested by the user. This system has a high potential for delivering heating and cooling loads, achieving a coefficient of performance of 1.6 in the heating mode and 0.8–1.1 in the cooling mode. These results are promising given the current need to reduce negative environmental impacts in the building sector yet maintaining the same level of thermal comfort.

Thermal performances of building walls are significant for energy conservation. However, very few non-destructive evaluation methods exist to quantitatively diagnose the building walls in situ due to the walls’ large thickness. Moreover, most of the existing methods are inconvenient to implement in situ and take a long characterization time. This paper studies transient heat transfer to estimate the wall's thermal properties based on the thermal quadrupoles modelling. Semi-infinite boundary condition is assumed at the rear face of the wall. With this assumption, only the front face response of the wall is considered. The evaluation time is then effectively reduced within a few hours, and the diagnosis in situ is simplified without the measurement on the rear face of the wall. Experiments are carried out on two traditional multi-layered building wall cases using heating lamps. With the measured surface temperatures and heat fluxes, the unit-pulse response and unit-step response at the front surface of the investigated wall are reconstructed through a deconvolution approach and a TSVD (Truncated Singular Value Decomposition) inversion. The unit-step response curve is directly characterized by the thermal resistance, thermal effusivity and heat capacity of the wall, thus allowing us to estimate the wall properties. The characterization time for the two cases is less than 10 hours.

The main drawbacks faced by researchers to successfully implement organic-PCM as materials to improve the thermal performance of building systems are their low thermal conductivity, their high flammability, and their low thermal cycling stability. T In the present work, authors present a new enhanced PCM formulations aimed to solve the stated disadvantages in organic bulk-PCM. The new enhanced PCM were prepared by adding high thermal conductivity particles and two kinds of flame retardants into organic PCM (paraffin and fatty acid eutectic mixtures). In the first stage, the effective thermal conductivity of organic-PCM was increased by using two different methods: directly dispersion of powder graphite (PG) bulk-PCM and vacuum impregnation of PCM into expanded graphite (EG). In the second stage, the fire reaction behaviour of the thermal conductivity enhanced PCM formulations was improved by adding two kind of flame retardant: magnesium hydroxide and ammonium phosphate (APP).. Their fire reaction behaviour, thermal conductivity and thermophysical properties were measured by adapting the dripping test (UNE 23727-90), the hot-wire method and Differential Scanning Calorimetry (DSC), respectively. The enhanced PCM composites show a self-extinguished behaviour in terms of fire performance mechanism. The EG working with endothermic and phosphates flame retardants improve the fire performance of PCM by acting as a synergic system and the thermal conductivity is increased. However, their thermal storage capacity is significant decreased due to the large amount of flame retardant added (up to 40%). The thermal reliability was also tested, the enhanced PCM composites were stable up to 1000 thermal cycles.