External Partitions Research Articles

Shaping of Selected Elements for A Low Energy Building

Reaching the standard of low energy building requires fulfilling criteria of energy saving and thermal protection as well as humidity criterion on design and exploitation stages. The basic factors shaping energy saving construction include among other: building architecture, construction and material solutions of external partitions and building joints using modern thermal insulation materials (building casing), type and efficiency of ventilation, central heating and hot water preparation systems and integral management of a building in energy production. In this work, there is an analysis of shaping of selected elements for low energy consumption. Physical parameters of selected external partitions and joints were defined using professional computer programs taking into account external and internal air parameters. Additionally, there was presented the influence of installation systems efficiency and energy source used on demand factor for non-renewable primary energy EP. Based on performed calculations and analyses, there were formulated design, executive and exploitation guidelines in shaping of building elements for low energy consumption buildings.

Historical Earth Architecture in Terms of Climate Change in the Temperature Climate Area (Central Europe)

The paper deals with the earth architecture and the assessment of the impact of climatic change on its external constructions. The concept of earth architecture represents construction that uses unfired, raw soil as a building material. This material, which forms the structure of the oldest building structures, was also widely used throughout Europe until World War II. The preserved, historic earth architecture, which represents a wealth of technical solutions, creates a European cultural heritage that should be protected. Unfortunately, in modern times, structures classified as earth architecture are subject to intense interference as a result of the need to adjust their structure to thermal parameters increased as a result of climate change. According to conservation rules, the only correct action in the case of thermal upgrading in this type of structures is the introduction of insulating material from the inside of the wall. However, the thermal upgrade carried out in this way is incompatible with the principles of building physics. In addition, incompetent implementation of work or incorrect application of insulating material, ignoring the risk of inter-layer and surface condensation, can lead to the introduction of moisture in the structure, the appearance of moisture that promotes the development of mould, fungi or biological damage to the structure. The aim of the conducted research was to determine the optimal solution in the field of thermal insulation of external partitions for the two most popular earth architecture technologies found in Europe, namely: a structure made of compacted earth (French: pisé, Polish: ściany bite, ziemnościany, glinobitka) and a half-timbered structure filled with trusses or braids and then covered with ground with chaff (French: torchis, colombage), or filled with raw or burnt bricks (bolt construction).The first part of the paper defines materials for inside thermal insulation of external construction partitions, from traditional (cork boards, sheep wool, wood wool) have been collected and described by the latest, such as aerogels made of silica with nanoporous structure and vacuum insulation - VIP (Vacuum Insulated Panels). The second part presents, theoretical, exemplary calculations for selected types of walls of earth architecture from the walls made of compacted soil with a thickness of 40 cm and a half-timbered construction with 14 cm thick filled or plaited braids were carried out. The computer program WUFI Light was used to carry out the calculations. The conducted research suggests that in the case of walls made of compacted soil, the use of any insulation technology does not effect on its durability and efficiency, while for walls with a wooden structure filled with unexploded soil, available insulation materials are unsatisfactory.

Practice in the Field of Thermal Retrofitting in Historic Buildings and Preservation of the Authentic Tissue of Façades of Historic Buildings in Poland

The pursuit to reduce emissions of harmful substances to the atmosphere resulting from the combustion of fuels for heating purposes makes a building more ecological and environmentally friendly. All operations aimed to limit emissions of pollutants into the atmosphere are motivated by the growing environmental awareness of developed societies and alarming reports on the global warming and its effects. In Poland, legal regulations are the answer to this problem. According to them, it is necessary to reduce the limit values of the heat transfer coefficient for partitions in rebuilt buildings. These values will be successively tightened until 1 January 2021. The compliance with the limits of the heat transfer coefficient is also required for historic buildings. For obvious reasons, historical buildings do not meet the technical requirements imposed on modern architectural structures. The constructional technique of partitions in historic buildings and building materials used in them require to undertake additional actions to provide thermal extra insulation of such buildings. The provision of extra insulation of historic buildings so that they can meet the assumed technical requirements is a challenge for designers and manufacturers of materials used for extra insulation in buildings. The first part of the paper covers the influence of modern thermal retrofitting methods and techniques applied in historic buildings conducted under the provisions of law onto the preservation of authenticity of the historical tissue of monuments. The paper analyses a variety of traditional and most recent methods and materials used in the provision of thermal insulation of external vertical partitions in historic wooden and brick-based buildings with wooden and masonry structures. Then the second part of the paper based on the conducted analyses determines the effectiveness of the adopted thermal retrofitting techniques, threats resulting from the applied methods towards the authenticity of historic building structures. At the same time, a set of factors which are relevant to the preservation of the authentic character of historic buildings was specified. To sum up, on the grounds of the conducted research studies it was indicated that the thermal retrofitting methods applied currently in historic buildings based on the provision of extra insulation for vertical partitions (applied from the inside of buildings) in reversible techniques do not admittedly devastate the authentic structure of walls but still do not ensure the expected and required technical parameters (and in the case of wooden architecture they lead even to accelerated degradation). The effective thermal retrofitting methods involving external extra insulation of partitions damage the authentic tissue of monuments. As a result of stricter legal regulations and a lack of good thermal retrofitting methods, it may be necessary to decommission historic buildings from their use.

Energy Analysis And Cost Efficiency of External Partitions In Low Energy Buildings

Energy efficiency is a very important factor in the construction sector. Construction consumes about 40% of total energy consumption in the world. New buildings in Poland and other European countries are designed according to strict requirements. An important aspect is to ensure thermal protection of the external partitions. To meet the requirements of thermal protection, the heat transfer coefficient of the building barriers must be at the appropriate level, specified in the Technical Conditions. Calculation of heat transfer coefficients of external walls, however, do not assume dynamic influence of external and internal environment conditions. The dynamic influences of environments on both sides of the barrier affect the thermal resistance, and thus the energy consumption and heating costs. In the experimental building of the Malopolska Laboratory of Energy Efficient Building, located on the campus of the Cracow University of Technology, experiments are carried out to describe the phenomena occurring in the partitions. The building has over 3000 temperature sensors built into its construction. Many temperature sensors are placed in the external walls. At the same time, measurements of temperature, humidity and solar radiation are recorded. These data will allow the analysis of phenomena occurring in the external wall under various weather conditions.Temperature sensors were placed in the construction layer. Subsequent sensors are arranged between the insulation layers, which are arranged in four layers of 5 cm. The last sensors were located on two sides of the ventilated slot. The gap is similar to external conditions. The experiment is to provide an answer to the extent to which wind, sun or rain affect the deterioration or improvement of the thermal resistance of the external wall. The results from the measurements will be compared with the calculated temperatures in the partition. This experiment will allow assessing whether the methodology for calculating the thermal resistance and temperature drops in the partition is accurate. In the second part, the Authors will analyse the purposefulness of using modern thermal insulation materials such as aerogels in terms of cost.

Energy and Cost Analysis of Adapting an Existing Building to 2017 Technical Requirements and Requirements for NZEB

Energy efficiency is a very important factor in the Building sector. Building sector consumes about 40% of the world total energy. At present, new buildings in Poland and other European countries are designed according to very strict requirements. The problem arises when we take into consideration large number of the existing buildings. These buildings, especially the ones built in the last century, consume a lot of heating energy. Thermal protection requirements for the existing buildings subjected to thermo-modernization are specified in the technical regulations. Thermal protection requirements for thermo-modernized buildings in different countries are different. In Poland, a thermos-modernized building must meet the requirements for thermal protection of external partitions. In Ukraine, the requirements of thermal protection are modelled on European regulations. In Ukraine’s, thermos-modernized buildings must meet the requirements for thermal protection of external partitions and primary energy requirements. However, in Poland thermo-modernized buildings do not have to meet the requirement for a non-renewable primary energy factor – EP. [kWh/(m2y]. The existing buildings do not always have the option of converting a non-renewable heat source into renewable heat sources. In the article, the authors presented the energy analysis of adapting an existing building to the current technical requirements in Poland (WT 2017) and to the level of requirements for buildings of “almost zero energy consumption NZEB” (WT 2021) and adapting an existing building to the current technical requirements in Ukraine. The analysis was carried out based on thermo-modernization audits carried out for a single-family residential building. The analysed building was built in 80’s in traditional technology. It is a two-story building located in Krakow. The audits considered various options for improving energy efficiency. Financial outlays for each variant will be determined. The authors of the article pointed out that comfort in buildings subjected to thermo-modernization a very important issue. On the example of an existing residential building, the authors analysed how to improve the vibration comfort of use in the rooms of a building.

Analiza porównawcza parametrów fizykalnych wybranych złączy typu ściana zewnętrzna–okno po dociepleniu

In the article there is presented a comparative analysis of physical parameters for selected joints of external partitions after insulation from internal and external sides using the TRISCO computer program. Based on calculation results and parameters of internal and external air, and variants of material sets for external partitions the thermal and humidity evaluation of joints was performer in view of binding legal regulations. The choice of material layers systems and their joints after insulation should be based on detailed calculations and analyses with taking into account exploitation conditions and changing parameters of external air.

Evaluation of energy efficiency of external stud partitions with use of numerical analysis

The need to save energy necessitates the search for solutions that would enable us to reduce heat losses. Currently the majority of investments are financed with use of mortgages, that is why the investors search for optimal technological solutions i.e. guarantee high energy savings. One of those solutions is construction in frame technology. This technology allows to achieve the heat transfer characteristics of a passive house with partitions that are ca. 40% thinner than their counterparts in traditional brick technology. According to different sources detached houses use ca. 70 ÷ 80% of the energy for heating. The subject of the article was the analysis of total heat loss through vertical wall of detached home made of wooden stud structure and for two types of steel stud structure – made of fully enclosed and THERMO profiles. On the basis of the literature recommendations and normative documents dependency calculated heat loss by transfer while computer simulation shows how thermal bridges of adopted solutions affect heat loss. For the purpose of analyzed external partitions heat loss was compared for heating season in buildings in each of the climate zones of Poland. What was also analyzed was the cost of heating for different fuels. The analysis showed significant differences in the adopted solutions. For example in case of gas central heating the difference in annual bills for different climatic zones can be ca. 20%, and the difference in costs of heat loss between the wooden stud framing and the steel stud framing is over 30%. The results show that use of appropriate technology can minimize those losses, thus securing significant lowering of heating bills. In turn, thanks to MES-e-based calculations, it is possible at the design stage to analyze the technological and construction solutions which are extremely important during the operation of the facility.

A criterion for stability of cluster synchronization in networks with external equitable partitions

Networks of nonlinear dynamical systems may exhibit a collective state, known as cluster synchronization, characterized by the formation of groups, where the units within each cluster converge to the same behavior that is distinct for each cluster. In this brief paper we derive a criterion for local stability in Milnor sense of this synchronous state that is expressed as a simple relationship between the maximum Lyapunov exponent of the uncoupled dynamics, the coupling coefficient, and one eigenvalue of the graph Laplacian spectrum. In the last part of the paper we discuss the application of the criterion to networks design and control.

Selected aspects of design for internal partitions and construction joints in low energy consumption buildings – a case study

Sustainable building is construction approach which is friendly to both humans and the environment, saving natural resources and counteracting pollution. The most essential design and execution features in this kind of construction approach include: the use of renewable energy sources to preserve natural resources; lowering the energy consumption of technological processes; decreasing the amount of material waste (by changing or modernising the building material technologies used); limiting of energy consumption of existing buildings and those being designed; modern installations in buildings; computer aid in sustainable building design.This paper presents principles for the design of external partitions and their joints using innovative thermal and insulation materials regarding their thermal and humidity requirements. Integral design elements in this range include certified computer programs which use numerical calculations allowing for parameters of external and internal air. The introduction of new thermal and insulation materials has a crucial impact on processes inside partitions and building joints. That is why the choice of a material layers system should be based on individual calculations considering ‘the specifics of the situation in which it will be applied. Based on the performed calculations and analyses, certain recommendation regarding design and execution were formulated in this paper for design of low energy buildings.

Use of fractional calculus in modeling of heat transfer process through external building partitions

This paper is devoted to experimental and numerical studies of heat distribution in an external building bulkhead. It analyzes the variation of temperature across the width of the bulkheads including the impact of changing external conditions. Mathematical model used in the research is formulated based on a fractional differential equation, which was proven to be a useful tool for describing this type of process in previous paper. Numerical results are compared with experiment data for different bulkhead configurations.

Deep thermomodernization of three residential buildings in Kryvyi Rih, Ukraine

This article presents the energy balance conditions of three multi-family residential buildings located in Kryvyi Rih, Ukraine. These buildings were built more than 40 years ago and are not insulated. A significant amount of energy is lost by the external partitions. The building’s heating is powered by municipal natural gas. A proposal for several thermomodernization variants for selected facilities are presented in the article. These variants of deep thermomodernization include an upgrade of the heating installation, insulation of external walls and roof, and the replacement of windows and doors in common areas. In view of the recent increases in the gas prices, the internal building's temperature is maintained below the thermal comfort. The presented variants include the proposal to leave the internal temperature at the present level, as well as to increase it to 20 °C. Heat transfer coefficients were calculated based on of the PN-EN 6946 standard and the heat demand for the buildings was estimated in the standard reference year in accordance with the PN-EN ISO 13790 standard. Results are compared with real values. The buildings’ models were prepared in the Audytor OZC 6.7. Pro software. The impact of appropriately sized photovoltaic system for each of the objects was also analyzed and the solar irradiation data has been taken from the RETScreen 4 software.

Modeling of heat consumption in a greenhouse using experimental data

The use of experimental research results to teach artificial neural networks was aimed at determining the relationship between heat consumption and measured variables. The mechanism of changes in heat consumption was determined by changes in external climate parameters, microclimate conditions in the greenhouse and parameters describing the functioning of the technical equipment of the facility. The accuracy of modeling the heat consumption in the case of changes in the properties of the building's external partitions has been determined. In a greenhouse, this is related to the functioning of an additional movable curtain - a thermal screen. MLP networks - multilayer perceptrons with hidden layers proved to be particularly useful for predicting changes in heat consumption. In the analysis attention was paid to the accuracy of modeling depending on the size of the measurement data set. The sources of information are collections with different intervals between registered measurement records, which were collected during the tests carried out during the full calendar year.

Impact of Envelope Structure on the Solutions of Thermal Insulation from the Inside

Abstract The article presents chosen issues related to the heat insulation of complex structure walls. Subjects covered in this study are building partitions that had been constructed in the so called “Prussian wall” technique and are located in the Upper Silesia region. Their technical condition as well as usable state are not satisfactory, especially in the light of thermal protection. One way of increasing their standard is insulating partitions. In case of historical monuments or rich architectural facades, typical insulation methods (the ETICS system) will not apply. Thus, the solution is to insulate external walls on the inside surface. This, however, causes moisture content difficulties, which means that steam diffusing through partition undergoes the process of condensation. The authors suggest their own solutions to the problem of insulating diverse external partitions and base them on the research conducted in situ. They use The School of Music in Gliwice as an example. The measurement results obtained here were used in “heat-water content” modeling of walls for which WUFI 2D programme was applied. As shown in numerical analysis, the thickness and the sort of insulating layer have a key impact on the partition water content including wooden elements of construction. In case of walls that are 25 cm thick, the water content in the wall itself and wooden elements increased alongside the insulation material thickness, but it did not excess the permissible level, otherwise wood degradation would ensue. For “Prussian walls” that are 12 cm thick and insulated on the inside we observe exceeding the level of 20% water content, which is critical for wood durability. These results present elementary problems that occur when buildings with “Prussian walls” construction undergo thermo insulation. Restoration process must be a compromise between the need to retain the historical aspect of a building and the need to bring them to modern heat and usability standards. On the basis of numerical analysis, possible solutions, which meet these criteria, have been proposed.

Analysis of Physical Parameters for External Partition Wall Joints Insulated from The Inside

The article introduces material and technological characteristics in insulation of external partitions from the inside. Selected joints of external partition walls were analyzed: corner joint of external walls and wall-window joint in a frame cross-section. The numerical calculations were performed using TRISCO and WUFI software with various isolation thickness and location. Basic physical parameters were defined: linear heat penetration coefficient Ψ, temperature distribution, temperature factor fRsi and real pressure distribution of steam and saturated steam, and humidity increase of external walls and their joints for insulation applied from the inside. Based on calculations and analyzes performed design recommendation were formulated resulting from application of insulation from the inside, arising from binding requirements for heat and humidity.

FACTORS AFFECTING THE DEMAND VALUE FOR NON-RENEWABLE PRIMARY ENERGY EP IN LOW ENERGY BUILDINGS

In order to achieve the standard of a low energy building it is needed to define the energy characteristics of the building with t-aiming at the minimal value of primary energy demand factor EP. The analysis of a building for energy saving concerns thermal parameters of external heat partitions, central heating installation efficiency, ventilation and hot water installation as well as using renewable energy sources. In this work there is an analysis of selected factors affecting PE factor in existing and new-designed buildings and there are valuable practical conclusions formulated.

Numerical thermal analysis of the vertical external partition made as the frame thin-walled steel structure

The article presents numerical thermal analysis of the vertical external partitions made in the lightweight steel framing technology. Steel posts that perform the structural role lead to the formation of linear thermal bridges and have a negative effect on the level of thermal transmittance U . Therefore, optimal solutions are being explored for such technologies. One of the solutions is to use perforated Thermo sections. The effect of perforated Thermo sections on energy loss was verified through comparison to the wall made of solid sections. Furthermore, the calculations analysed the effect of linear thermal bridges that are formed on wall connections in the corner. Computer simulation was employed to emphasize the significant differences in the temperature distribution in both analysed wall structures that resulted from constructional solutions.

Impact of external conditions on energy consumption in industrial halls

The energy demand for heating the halls buildings is high. The impact on this may have the technology of production, building construction and technology requirements (HVAC systems). The isolation of the external partitions, the location of the object in relation to the surrounding buildings and the degree of the interior insolation (windows and skylights) are important in the context of energy consumption. The article discusses the impact of external conditions, wind and sunlight on energy demand in the industrial hall. The building model was prepared in IDA ICE 4.0 simulation software. Model validation was done based on measurements taken in the analyzed building.

Graph partitions and cluster synchronization in networks of oscillators.

Synchronization over networks depends strongly on the structure of the coupling between the oscillators. When the coupling presents certain regularities, the dynamics can be coarse-grained into clusters by means of External Equitable Partitions of the network graph and their associated quotient graphs. We exploit this graph-theoretical concept to study the phenomenon of cluster synchronization, in which different groups of nodes converge to distinct behaviors. We derive conditions and properties of networks in which such clustered behavior emerges and show that the ensuing dynamics is the result of the localization of the eigenvectors of the associated graph Laplacians linked to the existence of invariant subspaces. The framework is applied to both linear and non-linear models, first for the standard case of networks with positive edges, before being generalized to the case of signed networks with both positive and negative interactions. We illustrate our results with examples of both signed and unsigned graphs for consensus dynamics and for partial synchronization of oscillator networks under the master stability function as well as Kuramoto oscillators.

Renovation of Large-Panel Buildings in Context of Urban Renewal/ Remonty Budynków Wielkopłytowych, Jako Element Rewitalizacji Miast

The article presents issues connected with renovating multi-storey precast concrete buildings, resulting from the consequences of construction defects occurring over the course of the building process and use of the buildings, as well as design flaws and construction defects when insulating external partitions. Analyses and conclusions which stem from them cover issues of renovation in the light of: damage in the vertical and horizontal joints, damage to the connection of layers in three-layer load-bearing and curtain walls, the effect of the damage on the possibilities of carrying out functional modernization of residential units, the effect of the damage on the effectiveness of thermo-modernization - new problems related to faulty insulation

The issue of the use of exotic wood in external building partitions

Exotic wood species are more often used in windows, doors, facades and shutters. A multitude of species and unique properties make its use is difficult. The use of exotic wood in outside partitions, exposed to the different climatic conditions, should be preceded by verification of its properties, sometimes specific (glueability, susceptibility to impregnation or finish paint coatings), which determining the reliability and durability of the final product.