Thermal Performance Of Buildings Research Articles

Multiple regional climate model projections to assess building thermal performance in Brazil: Understanding the uncertainty

Understanding the trends and uncertainties in Building Energy Simulation (BES) performance indicators under future climate conditions is crucial for mitigating issues such as overheating and power outages. To address this, we generated a set of weather files for all 27 state capitals in Brazil, considering six climate model projections (three General Circulation Models as driving models and two nested Regional Climate Models) and two distinct emission scenarios from the CORDEX project. We analyzed the variability in climatic variables and subsequently performed BES on a representative Brazilian social housing unit to evaluate its impact on the performance indicators outcomes. Consistent with previous studies, a substantial increase in cooling-related demands was observed in the more pessimistic scenario (RCP8.5) and mild increases in the more optimistic scenario (RCP2.6), with a trend toward stabilization after 2050. Regarding uncertainties, we found higher Relative Standard Deviation (RSD) values for the cooling degree hours indicator. The capitals in the Central-West, Southeast, and South regions exhibited greater uncertainty regarding temperature indicators, whereas the irradiation parameters displayed higher uncertainties in the Northeast region. For the BES outcomes, RSD values as high as 19.9% were found for cooling load values. It was also demonstrated that locations, periods, and scenarios exhibit different extreme climate model projections. Ideally, employing an ensemble of weather files developed from other models would help assess associated uncertainties in the building performance indicators.

Statistical Analysis of the Factors influencing the In Situ U-Value of Walls

Building thermal performance testing requires in situ measurement techniques that are well supported and validated by simulation with statistics to improve the accuracy of the results. Local on-site performance of building components is different from the theoretical one, influenced by factors affecting the building's thermal conditions. The current paper reviews the factors influencing the measured U-value results in the heat flux method based on quantitative findings of other studies through regression and correlation statistics. The findings regarding the current status of knowledge are limited to in situ methods without detailed insights of response time, sensitivity analysis, and thermal boundary conditions in the local context. Regression analysis between wall characteristics, time duration, temperature difference, and the measured U-value shows a very strong and statistically significant impact of these variables on the accuracy of the measured U-value of low transmittance walls. The R2 value indicates that three variables can collectively explain 91% of the variance in the measured U-value. There is a linear correlation between the wall characteristics and the measured U-value and a non-linear correlation between the time duration, temperature difference, and the measured U-value. Future work will focus on developing a measurement framework that considers time-dependent variables, dynamic weather, and uncertainty with high accuracy for different boundary conditions.

Thermal Behaviour Assessment of Brick Utilizing Plastic Waste for Enhanced Insulation Properties

Plastic waste, particularly hazardous types such as high-density polyethylene (HDPE) and Polyethylene terephthalate (PTE), is a critical problem in today’s world. Recycling plastic waste to produce new materials like concrete or mortar is an effective disposal method. One such solution is adding plastic waste to bricks to create an environmentally friendly and cost-effective option to produce high-strength bricks with thermal and sound insulation properties. The study intends to investigate the feasibility of reusing plastic waste as a mixture in brick production as an eco-friendly alternative to traditional bricks. To compare the thermal performance of buildings made of plastic waste bricks and traditional bricks, the researchers digitally created four sample bricks, each containing 0%, 5%, 10%, and 15% HDPE. The thermal performance of the brick-filled plastic bottle walls was then measured on-site at a real-time recording using a chamber and tested with the thermocouples connected to a data logger - T08 software. The results showed that 10% and 15% plastic waste brick composition had higher insulation properties with the difference between internal and external air temperature average of 6°C. The lower the external air temperature with the least amount of plastic waste recorded the lowest temperature difference average of 1°C. At the external temperature of 30°C, the 0% and 5% plastic waste bricks possessed the greater internal temperature, likely due to the external air temperature flow in the box’s confined space. Thus, further research and experimentation are recommended to investigate the thermal conductivity of plastic waste bricks and their correlation with the insulation properties of the material samples.Keywords: environment, construction, plastic waste, thermal performance

Performance analysis of a novel phase-change wall of wood structure coupled with sky-radiation cooling

The integration of phase-change materials (PCM) into building enclosures can effectively improve the thermal performance of buildings. In this study, a novel phase-change wall of a wood structure with embedded capillaries that can utilize sky-radiation cooling is proposed to reduce energy consumption. The performance of the proposed wall was experimentally investigated and compared to that of an ordinary wood-structured wall under summer conditions. The results show that the proposed wall can significantly reduce the internal temperature of the wallboard and indoor air temperature. Compared with a traditional room with ordinary wood structure walls, the room using the PCM wallboard results in a more stable temperature fluctuation. Furthermore, the load from the east-oriented wall was reduced by 15.63%, the optimum decrement factor was 0.44, and the intensity of thermal discomfort was reduced in all directions. Therefore, the proposed wall has great application potential for reducing energy consumption and improving thermal comfort.

Thermo-structural analysis and design for multi-functional membrane roofs of airport terminals

The utilization of large-span membrane structures in airport terminals has attracted considerable attention due to their excellent building aesthetics, reasonable structural behavior and multi-functional applications. Integrating structure and function is useful to improve thermal performance of such buildings. This study focuses on a scaled two-layer membrane roof in accordance with a newly-built aerogel-membrane airport roof and investigates the dynamic building thermal performance. The two-layer membrane roof is composed of an outer membrane layer as structural element, an air gap for ventilation and an inner membrane layer integrating aerogel mats. The effects of aerogel thickness, ventilation velocity and gap height are analyzed with multi-physics numerical tools. The structural behavior of the aerogel-membrane roof structure is examined in agreement with the building standards. The comparison between numerical and experimental results on solar irradiance is performed to demonstrate the reliability of numerical results under the typical environmental conditions. The thickness of the aerogel layer and the ventilation velocity are shown to have a significant effect while the air-gap height plays a minor role. A maximum temperature reduction of 4.7 °C demonstrates that using the proposed approach can improve building thermal performance. Moreover, temperature curves with small fluctuations indicate an efficient control of the indoor temperature. Therefore, the thermo-structural analysis method of the multi-functional membrane roofs can guarantee structural safety and facilitate building thermal performance control.

Energy performance analysis of alternative building retrofit interventions for the four climatic zones of Greece

Climatic conditions determine which retrofit strategy can result in a satisfactory improvement of a building's thermal performance. This study systematically investigates alternative retrofit actions, as standalone and in combination, and assesses their energy performance. The retrofit actions include i) insulation on the external walls, ii) the incorporation of phase change material (PCM) on the roof and the increase of the building thermal inertia, iii) a mechanical ventilation system with a summer period operation, and iv) a cool roof coating. The energy analysis concerns a typical two-story family building and the four climatic categories of Greece and is conducted with the INTEMA.building tool, a dynamic energy analysis software developed in Modelica language. The importance of the present study is that it serves as a guideline for the selection of the energetically optimum single retrofit or multiple-retrofit strategy regarding a building's location climatic data, and provides calculations concerning the annual heating and cooling loads, and the corresponding heat pump electricity consumption. The retrofit actions of external wall insulation and PCM roof addition are characterized as more effective in reducing a building's heating energy loads, while the mechanical ventilation system and cool roof coating are more effective in reducing a building's cooling loads. The quadruple retrofit strategy results in the maximum electricity savings for Heraklion (28.01%), Athens (21.15%), and Thessaloniki (16.54%), while the triple retrofit strategy which does not include the cool roof coating, results in the maximum electricity savings for Kastoria (10.79%). Lastly, an economic analysis of the energetically optimum renovation strategies is conducted.

A Qualitative Analysis Using Thermography for Characterization of the Built Environment

The revised Energy Performance of Buildings Directive (EPBD) recognizes nearly zero-energy buildings (nZEB) and building renovation as essential steps in the decarbonization of the built environment. A thorough understanding of existing buildings is a prerequisite for improving their thermal performance and ensuring that interventions are based on pre-existing conditions. This study investigates the use of thermography as a tool for identifying construction solutions and assessing the thermal performance of buildings. Initially, it addresses the benefits and limitations of this technique, as well as some results of a qualitative analysis and standard application of this technology. Specific conditions for capturing images on-site were identified, along with the relevant factors for interpreting thermograms under natural conditions. These images enabled the identification of previous works, changes in buildings, and the use of different materials and construction techniques, thereby contributing to the characterization of buildings. Consequently, they can be used in the diagnostic phase to enhance the accuracy of intervention solutions based on a better understanding of existing conditions.

Paper: Modeling and scenario analysis of residential building energy conservation in cities of different weather

Building models are used to predict energy consumption and CO2 emissions under current and future conditions and serve as a basis for building design. The most important energy saving potentials in buildings can be achieved by improving the thermal performance of building and the efficiency of the district heating system. This study investigated energy savings in buildings in cold and hot regions of China and Africa and developed a modeling approach for energy savings in heating and cooling of residential buildings. We have provided an overview of long-term scenarios for energy demand and carbon dioxide (CO2) emissions. Using the industry-renowned software RETScreen, parameter simulations and optimizations are performed over the three time periods (currently 2030 and 2050). As a result, it was found that energy consumption has also increased and the comfort level of high-rise houses is about 10–21% higher than that of cold regions. The comfortable temperature range in these different cities is between 20°C and 29°C. We have showed the difference between the observed values and the model simulations (model bias) for HDD and CDD in cold and hot regions of China and Africa. This model represents spatial patterns and scales observed in Harbin, Shenzhen and South Africa. These features are characterized by an increased north-south gradient in eastern China, a topographically dependent distribution in western China and an associated increase in average temperature. The most commonly used types of heating in residential areas are heat pumps (31%) and district heating (21%). This is also the preferred case for condensing boilers (17%). In non-residential areas, heat pumps (32%), district heating (27%) and condensing boilers (11%) are the most commonly used heating systems. The total energy demand in Africa and China will be increased from 2020 to 2050. It is expected that the total demand for primary energy in China will be 8770 Mtoe in 2050, which corresponds to an increase in demand for primary energy of 1.9%, while Africa will see an increase of 2.7%. Final energy consumption in China and Africa will be 5776 Mtoe and 970 Mtoe respectively.

Thermo-physical Characterisation of Plasters Containing Phase Change Materials (PCMs)

The integration of phase change materials (PCMs) within building materials is an interesting strategy to improve the thermal performance of buildings, thus reducing the energy demand for heating and/or cooling. To do so, the thermo-physical characterisation of the new enhanced materials is of outmost importance which, however, is difficult to carry out due to several limitations related to the most used techniques. To overcome these, a new alternative set up was realized, which allowed the thermo-physical characterization of different plaster samples enhanced with granular organic PCM. A steady-state test was conducted maintaining constant thermal gradients through which the thermal conductivity of the materials used was estimated. Then, a two-step ramp unsteady-state test was conducted through which the specific heat and the latent heat were estimated, showing a good agreement with values provided by the PCM suppliers. The estimated properties were then validated against experimental data acquired during the monitoring activity under real outdoor conditions of different wall samples on which the PCM-enhanced plasters were applied. With the estimated properties, RMSE values were lower than 1 °C for temperatures and lower than 2.50 W·m−2 for heat fluxes.

Producing domestic energy benchmarks using a large disaggregate stock model

Within the UK, domestic buildings account for 16% of total national emissions. Considerable improvements to the performance of the existing building stock will be necessary in the context of the UK’s commitment to emissions reductions, and for this to be achieved successfully and efficiently will require an improved understanding of the current performance of the stock. This paper presents an analysis of metered gas and electricity use from 808,559 dwellings with detailed building characteristic data in London, showing how energy use can be examined using a highly detailed, fully disaggregate building stock model. New gas and electricity benchmarks have been produced for houses (split by the level of attachment) and flats, for both gas- and electrically-heated properties. The paper shows how energy use varies with form, and how the choice of units influences the relative performance of different types. Comparing gas use across the types, for example, when calculated as kWh/m2, consumption follows building compactness, but when calculated as kWh/household, the trends follow building size. Finally, the paper examines how energy use varies with building thermal performance, using the Heat Loss Parameter (HLP), a standardised measure which accounts for thermal transfer through building envelopes as well as via air flow. Practical Application: This paper presents domestic energy consumption benchmarks based on measured not modelled data, produced from a large sample of London houses and flats. Results are shown for different dwelling types and heating fuels. Additionally, the relationship between gas use and envelope thermal performance is explored. The results will hopefully be beneficial for researchers, policy-makers and designers interested in better understanding current domestic energy use, and informing decisions about future improvements to energy efficiency within the stock. This paper also provides details for anyone interested in the production of the domestic benchmarks for the CIBSE benchmarking tool.

Preface

The 5th International Conference on Empathic Architecture (ICEA) is a biannual international conference organized by the Department of Architecture, Faculty of Civil Engineering and Planning, Petra Christian University. The 1st ICEA was initiated on 11-12 September 2014. The 2nd ICEA was held as an International Joint Conference with the 17th SENVAR on 1-2 March 2017. The 3rd ICEA was conducted on 25-27 April 2019, in which all papers presented were published in the IOP Conference Proceeding: Earth and Environmental Science Volume 490. During the pandemic, the 4th ICEA was held online on 26 February 2021.The 5th ICEA was held at Petra Christian University, Surabaya, Indonesia, on 19-20 October 2023, with the theme “Architecture for Health and Wellbeing.” The 5th International Conference on Empathic Architecture (ICEA) aims to gather researchers, scholars, and practitioners to share and exchange their knowledge and breakthroughs in architecture, especially for health and wellbeing. It is important to seek a holistic understanding of the impact of architecture, with its design features, on human health and wellbeing. Thus, an architectural design should be responsive to user needs, inspire, motivate, give meaning, and be spirit caring.The 5th ICEA was honored to present four reputable keynote speakers: (i) A. Ray Pentecost III, DrPH, FAIA, FACHA, LEED AP from UIA-Public Health Group, USA (ii) Dr. Yuan Chao from National University of Singapore, (iii) Ir. Adi Utomo Hatmoko, M. Arch., a professional architect in hospital design from Indonesia, and (iv) Dr. Ruzika Bozovic from the National University of Singapore.The subtopics of the conference include Healing Architecture, Inclusive Architecture Design, Architecture and Perceptual memory, Lighting for well-being, Building Thermal Performance, Indoor Air Quality, Building Envelope for Wellbeing, and Wellness in an Urban Environment. Through these topics, papers from authors have been presented during the conference days as a manifestation of empathy for users and the environment through Architecture and Built Environment. After the inspiring keynote sessions and discussions during the parallel sessions, the papers were curated once more before publication in this IOP Conference Series: Earth and Environmental Science.We would like to appreciate all keynote speakers, scientific committee, moderators, conference coordinators, and participants who have contributed to this conference. Finally, we hope this 5th ICEA proceeding could encourage the development of an architecture that empathizes with the user’s health and wellbeing.The 5th ICEA Editorial Teamhttps://5thicea.petra.ac.id/homeList of Scientific Committee, Organizing Committee are available in the pdf

Modeling of thermal energy saving in commercial buildings of Australia by balanced tree growth optimizer

Low-energy cases can be designed more efficiently by using analytical optimization. The non-linear thermal performance of buildings has led to the development of optimization techniques based on simulation. In building optimization, it is important to achieve superior solutions while minimizing calculation expenses. This study aims to optimize an Australian office building using the Balanced Tree Growth Optimizer (BTGO). It has resulted that more than 11.7 % of energy can be saved by the optimization process and also some energy-saving measures. A comparison of the utilized algorithm with benchmark algorithms including the Nelder-Mead method, hybrid Particle Swarm Optimization, Hooke-Jeeves, and Ant Colony Optimization for continuous domain showed that the BTGO can achieve better solutions and needs less computational time.

Relationship between shape and energy performance of buildings under long-term climate change

The Mediterranean basin is projected to experience the most significant effects of global warming in Europe. As climate change intensifies, resulting in hotter and lengthier summers, there will be a substantial rise in the demand for cooling systems. This study investigates the influence of the surface-to-volume ratio (S/V) in mitigating the impact of climate change on energy performance in Italian buildings, highlighting its often-overlooked status in current research and methodologies. Three different S/V ratio are considered to evaluate the building thermal performance (EPtot,nd) in compliance with the main Italian energy policies (issued in 2005, 2015, 2020) and three different representative Concentration Pathway (RCP) scenarios. The investigation encompasses all national climate zones in Italy. Results vary in relation to national climate zone (from A to F) and standards considered. When comparing EPtot,nd values in 2030 to the ones of 2050 and 2070, hot regions (Zones A, B and C) show an increase in EPtot,nd, reaching a maximum of 20 %, with minimal differences in almost every scenario. The climate zone D displays a varied behavior in EPtot,nd demand, with a trend of reduction for smaller S/V ratios. In climatic zone E, the EPtot,nd demand varies; if there is an increase compared to 2030, it is slight (up to 10 %), and this increase is further mitigated with a low S/V ratio. The cold climate zone F shows a slight reduction in the demand for EPtot,nd in 2050 and 2070, compared to the values required in 2030.

Enhancing Building Energy and Thermal Performance in Metro Manila, Philippines through Computational Fluid Dynamics-Assisted Analysis and Optimization

This study presents a detailed investigation of the energy and thermal performance of buildings in the Philippines’ metropolitan cities, targeting sustainability and indoor comfort against the backdrop of the country’s tropical maritime climate. Utilizing a blend of occupant surveys, energy audits, climate data analysis, and building envelope assessments, the research employs Computational Fluid Dynamics (CFD) simulations to accurately evaluate energy use and thermal behaviors in residential and commercial structures. Key findings include distinct nighttime energy consumption patterns in residential buildings and the identification of climatic challenges such as high temperatures and humidity. The study proposes effective design interventions like enhanced ventilation, shading solutions, and the integration of Phase Change Materials (PCMs) for improved thermal efficiency. Significantly, the research contributes to policy development by suggesting updates in building energy codes and advocating for energy-efficient practices. Overall, the study provides actionable insights for enhancing building sustainability and occupant comfort in urban Philippine settings.

Improving Thermal Performance in the University Classrooms

Universities are among spaces where it's important to ensure thermal comfort in indoor spaces, improving the occupants' well-being and productivity. The problem of the research was to study appropriate glazing systems for the spaces of the University of Baghdad because glazing systems are one of the most important elements of the indoor environments, and it has a major impact on the thermal performance of buildings. Glass is one of the most seasoned materials that are most utilized in the design. Since it is a diaphanous material, it allows sunlight to enter the building, increasing the space's temperature, cooling loads, and energy consumption in summer. The research followed the experimental method by studying and testing(conventional, advanced, and photovoltaic glazing)by Revit and Onyx Solar analysis in the Architectural Department classes to find the appropriate type of glazing in the spaces of hot, dry areas. The results showed that advanced glazing is the best by reducing the cooling loads andincreasingthermal performance quality. Photovoltaic glazing showed its efficiency in filling part of the electrical energy needs within the spaces of the Architectural department.

Applying infrared thermography to a latest residential building in France: case study, verifying dwellings national thermal regulations RT 2012 mainly thermal bridges assessment

High-performance insulation and airtight building envelopes are the two most important factors to optimize the building energy efficiency and thermal performance. However, thermal performance of building envelopes can be significantly affected by thermal bridging. Thermal bridges can take place at different locations of the building envelope, causing added transmission losses, increasing heat flow, lower inner surface temperatures. Thermal bridges are regarded in all national regulations for new buildings of all states of European Union (EU) but there are no specifications assessing balconies to wall junctions and the impact on the building thermal performance is not well regulated. In this paper, balcony to wall thermal bridge assessment using infrared thermography is highlighted. The originality is that, infrared thermography, has been applied to a real living latest building in the north east of France showing that there is noncompliance in the national regulations as some exigencies are not met. Thermography of thermal break windows and window doors has also revealed air leakage. The goal, is to illustrate that thermal imaging is a means of quality assurance to new building specifications and should include a clause specifying quality assurance procedure for balconies junction in national building regulations for all states of the EU.

Study of Hygrothermal Behavior of Bio-Sourced Material Treated Ecologically for Improving Thermal Performance of Buildings

Study of Hygrothermal Behavior of Bio-Sourced Material Treated Ecologically for Improving Thermal Performance of Buildings

EXPERIMENTAL AND COMPUTATIONAL STUDY ON THERMAL PERFORMANCE OF WOOD-PLASTIC COMPOSITES IN BUILDING ENVELOPE

Wood-plastic composites (WPCs) are attractive material for enhancing thermal performance of buildings by acting as an insulation surface. A fast and reliable experimental method was devised using a simple quasi-steady heating film (QSHF) method to measure the thermal conductivity of locally manufactured WPCs in Kuwait. QSHF used two blocks of standard materials compared with the classic methods, although it does not require a fixed constant heating source nor a cooling source. QSHF had a 10 cm × 10 cm × 0.5 mm silicon heating film controlled by a temperature controller and several transparent acrylic square blocks of the same size with 10 mm thickness as the standard materials. The top surface of the WPC samples was the cold side of the system, which is open to indoor temperatures of 22-23°C. The bottom layer can be maintained at any desirable temperature ranges from 25° to 55°C using the heating film to simulate the real outdoor environment. The thermal conductivities of locally manufactured WPCs type, namely FB16, FB18W, CD, and TD, were 0.0912, 0.1174, 0.3453, and 0.3078 W/m.K, respectively, obtained within 1 to 3 hours, which all fall below the standard value of 0.414 W/(m<sup>2</sup>.K) for composite walls and 0.1-0.2 W/m.K for wood. Multiphysics CFD simulation for DP45 sample and TRNSYS simulation for FB18W WPC in the building envelop were conducted which showed strong 2D effects and 3.3&#37: reduction in maximum cooling load in Kuwait, respectively.

Coupling effect of radiative cooling and phase change material on building wall thermal performance

Phase change material (PCM) featured with high latent heat thermal energy storage capacity and isothermal phase transition is employed into building walls decorated with radiative cooling (RC) coating, in order to modify the cooling effect on building thermal performance. Numerical analysis indicates that the RC coating causes exterior temperature of P-RC walls lower than ambient temperature, achieving maximum exterior temperature drop of 13.63 °C. Thermal buffer effect of PCM enables to shave the temperature peak and shift the temperature valley, inducing exterior temperature of the P-RC wall to fluctuate slightly in comparison to the RC wall. Interior temperature of the P-RC wall is found to approach to target temperature tightly. PCM located closer to the outside completes phase transition more rapidly, which is beneficial to levelling radiative cooling of RC coating. Exterior temperature of P-RC walls increases with augment of solar radiation intensity, ambient temperature and indoor temperature. Augment of PCM thickness, ambient temperature or indoor temperature is conducive to interior temperature. Latent heat thermal energy storage of PCM enlarges effective thermal capacity of walls, which is favorable to maintain interior temperature within target temperature. In conclusion, studied results highlight that radiation cooling can be improved by PCM, with substantial benefits to develop passive cooling available to building energy conservation.

Impact of Positioning Phase Change Materials on Thermal Performance of Buildings in Cold Climates

The building envelope, an essential component of any building, plays a critical role in meeting energy efficiency and thermal comfort requirements. Incorporating phase change materials (PCM) into the building envelope can offer an opportunity to minimize energy usage and enhance thermal comfort by offsetting daily temperature fluctuations. However, the optimal performance of PCM is contingent on the material’s placement and thickness within the building envelope. Therefore, this study investigated the effects of positioning and thickness of PCM on thermal comfort and heating loads in a lightweight timber building in Trondheim, Norway. Four scenarios were considered based on the positioning of the PCM layer in the exterior wall and roof. Using IDA ICE, parametric simulations were conducted for various PCM wallboard positions and thicknesses in the exterior wall and roof. In Nordic climates, adding PCM reduces the risk of annual overheating. The findings of this study showed that installing 75mm of PCM wallboard in the exterior wall’s inner layer reduced the annual heating load by 2.3%. Compared to the base case scenario, increasing PCM thickness reduced zonal maximum indoor air temperatures by up to 6.2°C. This study underscored the importance of carefully considering the placement and thickness of PCM in building envelopes for optimal performance.