Sensitivity Study on the Parameters of a Hygrothermal Transfer Model of Air, Heat and Mass Transfer

The energy performance of buildings represents a major challenge in terms of sustainable development. The buildings and buildings construction sectors combined are responsible for over one-third of global final energy consumption and nearly 40% of total direct and indirect CO2 emissions. In order to reduce the energy consumption of buildings and their harmful impact on the environment, special attention has been paid in recent years to the use of bio-based materials. Several works have been carried out in the last decades in order to model the coupled heat, air and moisture transfers in the building envelope but the difficulties lies in the identification of numerous parameters that the HAM proposed models use. In the present paper, a sensitivity study regarding the HAM parameters is implemented in order to apprehend the most determining parameters during the transfer processes. A reduced model based on these parameters is then determined.

Investigation of Thermal, Mechanical and Acoustic Performance of Bio-Materials Based on Plaster-Gypsum and Cork

The building sector is one of the biggest consumers of energy in the world and it is pushing the scientific community to find various alternative solutions to solve the problem of thermal insulation of buildings. Therefore, the selection of appropriate building materials is a major challenge for improving the thermal comfort and energy performance of buildings. In this scenario, the interest of plaster-based composites as insulating materials increases, in particular for new applications, as insulators for the building envelope, and this deserves to be studied. In this investigation, new plaster-based composites with cork were produced and tested at lab scale, in order to obtain cheap solutions with improved thermo-physical and acoustic performance. The results show that it is possible to improve the thermal, mechanical, and acoustic performance of construction biomaterials by using plaster as a binder and cork as a natural reinforcement: thermal conductivity was equal to 0.097 W/m.K, the compressive strength to about 2.30 MPa, and the transmission loss to about 40 dB. Keywords: Plaster-Gypsum; Cork; Thermal, Mechanical and Acoustic Properties.

Machine Learning Techniques Focusing on the Energy Performance of Buildings: A Dimensions and Methods Analysis

The problem of energy consumption and the importance of improving existing buildings’ energy performance are notorious. This work aims to contribute to this improvement by identifying the latest and most appropriate machine learning or statistical techniques, which analyze this problem by looking at large quantities of building energy performance certification data and other data sources. PRISMA, a well-established systematic literature review and meta-analysis method, was used to detect specific factors that influence the energy performance of buildings, resulting in an analysis of 35 papers published between 2016 and April 2021, creating a baseline for further inquiry. Through this systematic literature review and bibliometric analysis, machine learning and statistical approaches primarily based on building energy certification data were identified and analyzed in two groups: (1) automatic evaluation of buildings’ energy performance and, (2) prediction of energy-efficient retrofit measures. The main contribution of our study is a conceptual and theoretical framework applicable in the analysis of the energy performance of buildings with intelligent computational methods. With our framework, the reader can understand which approaches are most used and more appropriate for analyzing the energy performance of different types of buildings, discussing the dimensions that are better used in such approaches.

A Brief Report on the Actions towards the Introduction of BIM in the Macedonian Construction Sector

Although the building sector builds and renovates objects, the construction industry is currently due for a digital renovation. In this paper, we provide insight into the status of BIM adoption in North Macedonia as a step towards the digital transformation of the construction industry. The presented review on the current stage of development, benefits, and barriers is followed with showcasing the possibilities for using BIM for the assessment of the energy performance of buildings through case studies. Furthermore, the results of the conducted survey on BIM awareness and the proposed national roadmap for BIM adoption are elaborated on.

Low-Emissivity Window Films as an Energy Retrofit Option for a Historical Stone Building in Cold Climate

Low-emissivity (low-E) window films are designed to improve the thermal comfort and energy performance of buildings. These films can be applied to different glazing systems without having to change the whole window. This makes it possible to apply films to windows in old and historical buildings for which preservation regulations often require that windows should remain unchanged. This research aims to investigate the impacts of low-E window films on the energy performance and thermal comfort of a three-story historical stone building in the cold climate of Sweden using the simulation software “IDA ICE”. On-site measurements were taken to acquire thermal and optical properties of the windows. This research shows that the application of the low-emissivity window film on the outward-facing surface of the inner pane of the double-glazed windows helped to reduce heat loss through the windows in winter and unwanted heat gains in summer by almost 36% and 35%, respectively. This resulted in a 6% reduction in the building’s annual energy consumption for heating purposes and a reduction in the percentage of total occupant hours with thermal dissatisfaction from 14% (without the film) to 11% (with the film). However, the relatively high price of the films and low price of district heating results in a rather long payback period of around 30 years. Thus, the films seem scarcely attractive from a purely economic viewpoint, but may be warranted for energy/environmental and thermal comfort reasons.

A structured method to define goals when developing a building energy performance assessment method in a legislative framework

To boost the energy performance of buildings, the EU has established a legislative framework including the Energy Performance of Buildings Directive (EPBD). Through this document, EU state members are incentivized to set up a Building Energy performance Assessment Method (BEAM), tailored to the specific needs of the country. There is no standard definition for the energy performance of a building. Since the options are numerous, it is important for the policymaker to define the goals of their specific BEAM first, before developing the BEAM itself. The definition of these goals is a subjective matter and can differ when asked to different organizations in the building sector. To comprehend the desires and perspectives from each different group, a structured overview of the goals that are important for the specific region is needed. For this paper, a method was developed to provide this structured overview and was tested on the legislative energy performance of buildings (EPB) framework of Flanders, Belgium. The Flemish framework was initiated in 2006 and is still in action today. The method consists of two steps. In the first step, a multi-level tree structure for goal mapping based on the Goal Breakdown Structure (GBS) was developed. The main goal, reducing global warming, is on top of the tree structure, which then subdivides into many sub-goals on different levels. An example of a goal on the lowest level of the structure could be the insulation level of the walls. In the second step, prominent stakeholders in the Flemish building industry, including policymakers, researchers, manufacturers, contractors and building owners, were surveyed to capture their expectations from a BEAM and to query whether the current BEAM corresponds with those expectations. The goal of this survey was to receive qualitative, not quantitative input from the stakeholders. In total, 33 respondents completed the survey. The survey results showed that, in general, the desired goals have not changed substantially compared to the pre-set goals in 2006. Trias Energetica is still the preferred guideline for the decision-making process of the building owner, although its absolute power has decreased slightly and seems to be more prone to the conditions. The current indicator for the overall energy needs (E level) is still strongly preferred, while the recently introduced S level (assessment of the envelope) attracts mixed feelings in terms of usefulness to the entire EPB framework. The overheating indicator receives the most critique for not being accurate enough due to the simplified, single zone BEAM

The effect of weighting factors on income-related energy inequalities: The case of Sweden’s new building code

To ensure building construction with low heating demand, efficient use of sustainable energy carriers, and neutrality between heating technologies, Sweden recently introduced weighting factors (WFs) for different energy carriers which are now used in Energy Performance Certificates (EPCs). As EPC ratings are gaining increased influence in Swedish energy policy and regulation, with recent examples of buildings’ EPC rating acting as base for imperative regulatory requirements, the introduction of WFs is likely to have significant effects on how policy and regulations are distributed in the multifamily building stock. As residents often are directly or indirectly affected by policy that either impose or trigger measures to be undertaken in their building, the aim of this paper is to analyse how WFs affect the assessed energy performance of buildings in different resident income groups. The results show that overall, reduced energy performance from WFs was more common in high-income areas than in low-income areas. However, although the total number of buildings in the lowest EPC ratings was reduced after introducing WFs, the resulting income distribution among worst-performing buildings was more skewed towards low-income households than before introducing WFs. As imperative regulatory requirements previously have targeted worst-performing buildings, these results indicate that energy-related inequalities in the housing stock have become more prominent and should be considered as to not disproportionately burden low-income residents in the energy transition of the housing stock.

Design and implementation of nZEB buildings in Poland. Building certification.

The article will discuss the design and construction aspects of nearly zero-energy buildings (nZEB) in Poland. It is the newest building standard introduced by the Directive on the energy performance of buildings 2010/31/EU. The directive made the implementation of nZEB buildings compulsory in European countries. The article will present analyzes of the energy performance of nZEB buildings, in accordance with Polish legal requirements, and discuss the possibility of achieving this standard in terms of economic efficiency. An important issue is also the certification of newly designed buildings, allowing the promotion of buildings with more restrictive parameters than the minimum energy efficiency requirements specified for nZEB buildings. In the article, the authors will present the developed methodology for certifying buildings in Poland, based on the requirements related to energy efficiency, and on in situ testing of buildings. The article will also present examples of building certification in Poland.

Energy Performance of Buildings with Thermochromic Windows in Mediterranean Climates

This article presents comparative results on the energy performance of buildings in the Mediterranean. Many buildings in the Mediterranean exhibit low energy performance ranking. Thermochromic windows are able to improve the energy consumption by controlling the gains from sunlight. In this article, reference buildings in 15 cities around the Mediterranean are investigated. In this work, a dynamic building information modeling approach is utilized, relying on three-dimensional geometry of office buildings. Calculations of the energy demand based on computational simulations of each location were performed, for the estimation of heating and cooling loads. The presented study highlighted the need for high-resolution data for detailed simulation of thermochromic windows in buildings of Mediterranean cities. Temperature is one of the main climate parameters that affect the energy demand of buildings. However, the climate of Mediterranean cities nearby the sea may affect the energy demand. This was more pronounced in cities with arid Mediterranean climate with increased demand in air-conditioning during the summer months. On the other hand, cities with semi-arid Mediterranean climate exhibited relatively increased heating demand. With this parametric approach, the article indicates the energy saving potential of the proposed measures for each Mediterranean city. Finally, these measures can be complemented by overall building passive and active systems for higher energy reductions and increased comfort.