Additional Thermal Insulation Research Articles

The importance of using active thermal protection following restoration work on old buildings

The paper deals with the issue of humidity and the unhealthy environment of old buildings. Humidity is a very widespread problem not only in historical buildings, but also in newer buildings. This problem can be observed in various parts of the world and thus it can be said that it is a global problem. Humidity in these buildings causes an unhealthy environment, which has a negative effect on individual building constructions, but also on people’s health. Humidity is also associated with the form of disruption of the individual layers of the construction and the disruption of the thermal resistance of these constructions. Buildings such as these subsequently have an unhealthy environment. After a part of the description of the known issue, the contribution follows on from this part by indicating possible remedial interventions and analyses the systems of additional thermal insulation (ETICS, ATP), ensuring the improvement of the internal environment. Finally, the article presents possible connections and extensions of this research and its application directly in practice. The results of the proposed research will significantly contribute to the approach to rehabilitated older buildings and their long-term sustainability from an economic point of view, as well as the possible use of them.

Leveraging oxide reactive sputtering for thermal insulation in laser-heated diamond anvil cell

ABSTRACT We have developed an oxide reactive sputtering technique aiming at rapidly sputtering high-quality oxide films on a diamond surface, providing excellent thermal insulation in high-pressure and temperature experiments using a laser-heated diamond anvil cell (LH-DAC). We identified conditions for rapid deposition of an alumina layer on diamond anvils, showing deposition rates as high as 0.67 um/hr. We also investigated the deposition conditions of zirconia, which have lower thermal conductivity than alumina. Laser-heating tests were performed at high pressures and temperatures to evaluate the thermal insulation of the oxide film deposited on the diamond anvils. The heating efficiency of zirconia-deposited anvils was higher than that of the alumina-deposited ones. Our zirconia-sputtered anvils were capable of generating up to 2580 K at around megabar pressure without additional thermal insulation, demonstrating the potential of this technique for ultra-high temperature generation.

Thermal analysis of the window-wall interface for renovation of historical buildings

Due to the long time since their construction, some old buildings have experienced a decline in performance and do not meet contemporary requirements. Retrofitting methods, as opposed to demolition and reconstruction, are considered a more cost-effective and energy-efficient approach, particularly applicable to historical buildings with conservation significance. Exterior windows account for a significant amount of heat loss within the building envelope, but it is a challenge to improve its performance while retaining the historical appearance of the building when retrofitting. In this paper, a new design of the window-wall interface structure was proposed, which facilitated the incorporation of additional thermal insulation materials and mitigated the thermal bridge effect at the joint between the window frame and the wall. Comparative analysis with existing window-wall interface structures revealed the superior thermal performance of the proposed structure, with less heat transfer as well as smaller surfaces at risk of condensation. The structure was first implemented in a renovation project in Nanjing, providing an innovative approach for future exterior window renovations of historical buildings.

A Holistic Modular Solution for Energy and Seismic Renovation of Buildings Based on 3D-Printed Thermoplastic Materials

This paper introduces a novel modular retrofitting solution to enhance the energy efficiency and seismic resilience of building façades, particularly within the Portuguese context. In the context of Europe’s “Renovation Wave” strategy, and as a product of the nationally funded ZeroSkin+ project, the proposed renovation solution addresses the urgent need for sustainable building renovations to help mitigate climate change and meet European climate neutrality goals by 2050. Unlike traditional methods that often rely on non-eco-friendly materials without integrating seismic and thermal performances, the renovation solution leverages fused deposition modelling (FDM) 3D printing technology to introduce a dual-layered panel system. This system features a durable, UV-resistant PET-G thermoplastic outer layer and a cork interior to ensure additional thermal insulation. The integrated renovation solution shows a 42% improvement in seismic reinforcement’s out-of-plane capacity and achieves U-values as low as 0.30 W/m2·K, exceeding Portugal’s thermal efficiency standards (0.35 to 0.50 W/m2·K). The proposed renovation solution also embraces circular economy principles, emphasising waste reduction and recyclability.

Eksploatuojamo šilumos punkto termoizoliacijos būklės termografinis tyrimas

Promoting technological progress is a necessary measure to reducing the energy consumption of buildings and contributing to sustainable energy. It is important, not only to efficiently use heat in the building, but also to reduce energy losses in heat supply networks and heating point. Thermography allows for a more accurate assessment of the state of thermal insulation and can help identify and determine small but important areas of heat loss. The expected effect of additional thermal insulation could be up to 1 % of saved heat energy. However, considering the relatively high temperatures of non-insulated elements and long heating seasons (duration varies up to around 200 days), an economic effect can also be expected. Keywords: heat transfer, thermography, heating point, central heating.

Buildings made of massive timber logs with a derogation from the application of technical conditions for traditional masonry technologies

Timber log walls are a unique form of construction - erected from solid material, they are both a building structure and a thermal barrier. Walls of wooden logs have numerous advantages, especially favourable physical and mechanical properties, including insulation and thermal capacity. The technical conditions, which are the Polish interpretation of the Nearly Zero Energy Building (nZEB) building, which a newly designed building must meet, must meet 2 conditions simultaneously: the value of the EP index, which determines the annual calculated demand for non-renewable primary energy for heating, ventilation, cooling and preparation of domestic hot water for the entire building, and adequate thermal insulation of the external walls. Calculating the thermal insulation of a wood partition, relying only on thermal conductivity coefficients without considering other properties of the material, does not reflect the true insulating properties of wood. The lack of research on the insulating properties of wood, and thus the lack of national technical and installation requirements for log houses seriously limits the development of this type of construction and forces to undertake reliable research and development work in this area. The proposed introduction in this type of building of the methodology of the so-called Integrated Energy Design (IED) allows to carry out multi-criteria analysis of design variants at the stage of the virtual model in the BIM standard, in terms of the final energy efficiency of the building. Conducting various types of variant analyses and simulations allows to achieve optimal energy efficiency and to verify and correct the adopted solutions. The high energy efficiency of the building demonstrated by such simulations can be the basis for a deviation from the current regulations, which will allow the implementation of newly designed buildings in massive log technology, without the need for additional thermal insulation. As a result, it will be possible to preserve the unique architectural expression of buildings erected with this technology, with visible massive timber logs both on the exterior facades and on the interior.

Improving Energy Efficiency in a Building Using Passive Energy-Saving Measures

Abstract We are going through a time when environmental, economic and social concerns, intensely amplified by climate change, by the depletion of resources, are growing. In this context, setting targets such as reducing energy consumption in the buildings sector, energy efficiency, and the use of renewable energies are becoming a priority, both at national and international level. Improving the energy efficiency of the existing building stock is important, not only for achieving national medium-term energy efficiency targets, but also for meeting the long-term objectives of the strategy on climate change and the transition to a competitive low-carbon economy by 2050 (https://energy.ec.europa.eu/system/files/2014-11/2014_article4_ro_romania_0.pdf). Currently, the building is considered as a structure in a continuous evolution, which in time through maintenance, rehabilitation and modernization works will meet the requirements expressed by the user. The case study presented in the paper presents an analysis from the point of view of improving the energy efficiency, reducing the energy requirement in a building using passive energy-saving measures, that is, the additional thermal insulation of an element of the building envelope. The materials selected for this research are: expanded polystyrene, basaltic mineral wool and cellulose fibres.

Simulation of Illumination and Wind Conditions for Green and Fed Cities Using CFD Software

To avoid ecological catastrophe, most cities are moving toward green building. The critical component is greening – conventional and green structures. Urban agriculture is a very prospective direction. Green roofs, terraces, and rooftop greenhouses are the most promising places for growing. This solves multiple tasks: heat loss recovery for planting (for rooftop greenhouses), additional thermal insulation, optimized logistics, increasing pollinator populations, avoiding pests, etc. In different-height districts, there are problems with natural illumination and winds. No good urban wind theory has been developed. The winds can be simulated in CFD software using a 3D model of a district. Most of the software can simulate solar radiation for thermotechnical calculations only. It should be simulated in other special software. The approach to calculating solar radiation is proposed using CFD software without additional needs. The unique "integrator" material should be added to the engineering database. Its thermotechnical properties can be set to obtain a temperature numerically equal to the exciting parameter. Application is shown in an example of a different-height building with a green roof. The results show areas most favorable for growing photophilous and shade-tolerant plants and placing cleaning and phytoncidal plants for maximum air quality in stagnation zones.

Design of a universal apparatus for heat treatment of meat and vegetable cooked and smoked products with the addition of dried semi-finished products of a high degree of readiness to the recipe

The object of the study is the process of smoking a molded meat-vegetable product with the addition of a dried semi-finished product of a high degree of readiness based on Jerusalem artichoke, zucchini, and carrots. Combined health products will satisfy the demand of end users for functional products of the new generation and will solve the technological problems of manufacturers in accordance with European competitiveness procedures. They will expand the offer of products with rational nutritional, taste, aesthetic characteristics that will meet the modern trends of craft producers, NoReCa business, and consumer expectations. A universal device for heat treatment of meat and vegetable products under hot and cold smoking conditions has been designed based on a film-like resistive electric heater of the radiating type. The device uses Peltier elements placed on the outer surface of the smoke generator and, at a temperature of 45 °C, they form a low-voltage power supply (~3...4 W) from the conversion of secondary heat. Cold smoking is carried out in the temperature range up to 25 °С, provided that the outer surface of the heater is covered with a coil heat exchanger through which the coolant passes. During hot smoking, the air medium is in the heat exchanger (additional thermal insulation of the chamber). The uniformity of the temperature field of the meat-vegetable product (meatloaf with a diameter of 0.08±0.01 m) during hot smoking has been confirmed, provided that the center of the loaf reaches 65 °C and the total duration of the process is 5.5 hours. The introduction of dried semi-finished products of a high degree of readiness into the recipe of meat loaves increases the yield of the product by 18 % and the mass fraction of protein by 25 %. The moisture retention capacity of the experimental meat product increases by 11 % with a 33 % decrease in calorie content, which indicates an improvement in its quality indicators compared to the analog

Adaptive Dynamic Building Envelopes with Solar Power Components: Annual Performance Assessment for Two Pilot Sites

Energy consumption reduction and thermal quality improvement constitute two major aspects of building design and/or retrofitting. Following the current energy transition trends, a state-of-the-art solution is the implementation of Adaptive Dynamic Building Envelopes (ADBEs), which are capable of integrating different technologies and components. The purpose of this investigation is to assess the annual performance improvement of two actual building spaces retrofitted with ADBEs, consisting of Building Integrated Photovoltaics (BIPVs), additional thermal insulation, mechanical ventilation system with heat recovery, and solar air heaters (SAHs). Both buildings are pilot sites for the EU Horizon 2020 Plug-n-Harvest project and are located in two rather different climate zones, i.e., Cardiff, Wales, and Grevena, Greece. Moreover, through detailed dynamic modeling with the use of Modelica language, this study attempts to accurately capture all interactions between buildings and all the aforementioned ADBE components. The simulations compared the energy performance and indoor temperature levels in each space before and after the installation of the ADBEs. The results showed that the harvesting of renewable energy through the ADBE system could potentially contribute 60% and 21.8% to the annual electricity and heating load of the space in Cardiff, respectively, and 43.5% to the annual electricity load of the building space in Grevena.

Study of the effect of an additional layer of insulation on the rate of heat loss in the cabin of an electric vehicle in conditions of extremely low arctic temperatures

This article examines the reduction of speedand heat loss in the passenger compartment of an electric vehicle (EV) when installing an additional thermal insulation gasket on the doors. The study was conducted in conditions of extremely low outdoor temperatures that occur in the winter season in the northern and arctic regions. To conduct a series of observations, the doors of the passenger compartment of an electric car were equipped with an additional (second) heat-insulating rubber gasket. The results were recorded for two groups of measurements, at an outdoor temperature of -25 ... -30 0C and at outdoor temperature -35 ... -40 0C.

Future trends in materials manufacturing for low carbon building stocks: A prospective macro-scale analysis at the provincial level

In order to reduce the greenhouse gas (GHG) emissions of buildings, the literature has investigated many strategies to tackle operational emissions, which are traditionally the largest contributor to overall emissions. As a result, embodied emissions are gaining increased attention, not only due to the decrease in the relative share of operational emissions but also due to increased material needs, e.g. the use of additional thermal insulation in buildings. Some of these strategies, such as the decarbonisation of the energy grid, could also help decrease the embodied emissions of building materials. The objective of this paper is to investigate the influence of increased renewable electricity use in building material production. It also examines future trends in the manufacturing processes – such as an intensified use of bioenergy, improvements in energy efficiency and the introduction of carbon capture and storage – on the GHG emissions of buildings. These strategies are analysed in a combined “future materials” scenario on a macro scale within the Tyrol province in Austria. With a focus on new residential constructions, six design variations of two building case studies are assessed using life cycle assessment. They are then projected to 2050 at the provincial level. The results of the future materials scenario point towards a promising embodied GHG reduction, up to 19% in this analysis. Larger mitigation effects would appear in the 2040s and 2050s, meaning future manufacturing technologies can be seen as a long-term investment. Their reduction potential surpasses the potential impact of an increase in wooden constructions. The latter achieved up to 7% reduction in GHG emissions, which would be mostly visible in the early decades rather than in later ones. These reduction percentages remain lower than those which could be attained at the operational energy level, with reductions of up to 72%. The obtained results are discussed in the light of other published regional and global studies to identify the possible sources of variations. Critical reflections on carbon capture and storage, as well as renewables, additionally highlight the intrinsic challenges of such key technologies.

The Use of Thin-Layer Insulation Material in Technical Installations in Building Reconstructions

This article is a part of a scientific work dealing with the research of thermal insulation properties of thin-layer insulation material made of hollow glass-ceramic microspheres in relation to technical equipment of buildings. Until now, there has been a lack of scientific studies describing the effectiveness of thermal insulation properties of thin-layer insulation materials on distribution systems or technical equipment. Thin-layer thermal insulation materials may have a great potential for use in building reconstructions and associated reconstruction of distribution systems, where there is often insufficient space for additional conventional thermal insulation and where energy savings of the whole system need to be addressed. For this reason, a series of laboratory measurements were made and in this particular case, the insulation material was applied in a 2 mm layer to the heat storage tank and the heat losses of two models of the heat storage tank (without insulation and with thin-layer insulation coating) were compared. In addition, for a more comprehensive view of the issue, the two models were compared in two situations that may occur in practice, which are the cases of free and forced convection.

Natural high-porous diatomaceous-earth based self-floating aerogel for efficient solar steam power generation

The application of solar steam generation in seawater desalination is an effective way to solve the shortage of fresh water resources. At present, many kinds of photothermal conversion materials have been developed and used as evaporators in seawater desalination. However, some evaporators need additional thermal insulation or water supply devices to achieve efficient photothermal conversion. In addition, their complex, time consuming and no scalable preparation process, high cost of raw materials and poor salt resistance hinder the practical application of these evaporator. Owing to its distinctive nanoporous structure, diatomite as fossilized single-cells algae diatoms is a promising natural silica-based material for seawater desalination. They are taken from sea and that makes true sense to use them in the sea. Herein, we report the first example of synthesis robust three-dimensional (3D) natural-diatomite composite by assembling polyaniline nanoparticles covered diatomite into the polyvinyl alcohol pre-treated melamine foam frameworks and demonstrate its application as new evaporator for seawater desalination. The porous framework does not only improve the sunlight scattering efficiency, but also offer large network of channels for water transportation. The inherent mechanism behind salt desalination process involves the absorption of water molecules on the surface of the internal silica micro-nano pores, and evaporation under the heat induced by the polyaniline absorbed sunlight. Meanwhile, the metal ions are segregated by many available pores and channels to achieve the self-desalting effect. The developed evaporator possesses the superiority of multi-stage pore structure, strong hydrophilicity, low thermal conductivity, excellent light absorption, fast water transportation and salt-resistant crystallization as well as good durability. The evaporation rate without an additional device is found to be 1.689 kg m−2 h−1 under 1-Sun irradiation, and the energy conversion efficiency is as high as 95%. This work creates a platform and develops the prospect of employing green and sustainable natural-diatomite composite evaporator for practical applications of seawater desalination.

The effect of thermal insulation of the lining on the heat exchange of rotating apparatuses

Rotary kilns are used in many industries to process bulk raw materials. In the building materials industry, rotary kilns are widely used for heat treatment. However, the fuel utilization factor in rotary kilns is extremely low. Thus, the bulk of cement clinker is fired in furnaces, the thermal efficiency of which does not exceed 55-60%. Therefore, the task of increasing the efficiency of such units is extremely relevant. In operating furnaces, heat losses to the environment only through the furnace body reach 20-25% of the total heat of combustion. In this case, one of the main factors determining the thermal efficiency of furnace operation is the value of thermal resistance of lining.
 The aim of the work is to study the evolution and temperature changes in the rotary kiln lining made of shaped refractory to reduce heat losses to the environment and improve the efficiency by increasing the thermal resistance of the lining. The increase in thermal resistance is achieved by changing the shape of the refractory by creating appropriate cells and introducing additional fibrous insulating material into them.
 A mathematical model and software have been developed and numerical calculations have been carried out to determine non-stationary temperature fields in the lining with a thermal insulating element and to substantiate the choice of an appropriate thermal insulating fibrous material.
 Analyzing the calculation results, it is possible to conclude about the expediency of using a lining with increased thermal resistance. The use of this technical solution makes it possible to reduce heat losses through the housing by 18-24%, to increase the amount of transferred material in the working zone by 1.5-8% due to the creation of an appropriate temperature field in the working volume, and to reduce the mass of the lining and the furnace as a whole. and increase the energy efficiency of the thermal unit.
 The presence of cells with additional thermal insulation contributes to the emergence of thermal pulsations having oscillatory character and affecting the intensification of heat and mass exchange processes, which in general contributes to the performance of the thermal unit.
 A significant advantage of this method is also the fact that increasing the energy efficiency of the furnace does not require additional fuel consumption, increasing the temperature or increasing the enthalpy of the combustion products.

Energy Consumption by DHW System with a Circulation Loop as an Energy Efficiency Component, Based on an Example of a Residential Building

In the EU countries, almost 50% of the produced energy is used in residential buildings. More than 25% of this energy is used to produce domestic hot water, of which almost 80% is used to heat water in domestic hot water circulation systems. This is due to high expectations on the part of residents based on their comfort, in particular regarding the supply of heat for heating and domestic hot water. In the course of their long-term research conducted on real systems, the authors confirmed that the operation of domestic hot water distribution systems causes significant costs, mainly due to heat losses. Therefore, typical variants of energy optimization of such systems were analyzed. Tests have shown that selected solutions, such as the use of control automation, are not sufficient, and recommended additional thermal insulation may not be applicable due to technical reasons. With an aim of finding a solution to the problem, the publication analyzes operational data from an existing heat source and domestic hot water circulation system in a residential building. On the basis of these analyses, a solution was proposed to reduce energy consumption within the installation by means of its hydraulic optimization. The reduction of heat losses in domestic hot water installation by means of a method presented by the authors is estimated at approximately 20%.

Research on energy saving of small public building envelope system

Recently, energy saving of small public buildings is gaining more and more attention. The envelope system takes the most important and fundamental part of reducing building energy consumption. In this study, a community center in Shanghai is used as an example to analyze the envelope of small public buildings. The structural design of walls, roofs, thermal bridges and shading measures is carried out. Comsol multi-physics simulation software is applied to perform two-dimensional simulation analysis on the heat transfer of the outer envelope structure of the community center to verify the energy saving effect of the outer envelope structure. This study indicates that small public buildings with additional rock wool thermal insulation panels could optimize energy performance in both winter and summer. The difference between the roof inner surface temperature of the building before and after retrofitting in winter is 26.96 °C, a difference of 1.95 °C; while in summer it is 2.26 less than before retrofitting when the temperature is cooled to °C 28 °C. The result of this study provides a new perspective for the research of energy saving in small public buildings.

Finite Volume Method Modeling of Heat Transfer in Acoustic Enclosure for Machinery.

This paper deals with the problem of heat accumulation in acoustic enclosures. Increased noise levels at production sites or manufacturing lines force the application of acoustic enclosures. Effective noise reduction due to enclosures often comes with the additional thermal insulation of the device, which in many cases causes a strong increase in the device operation temperature. This paper presents the methodology of thermal phenomena numerical modeling based on the potential influence of acoustic enclosures on the increase in device operation temperature. The proposed model consists of an original acoustic enclosure concept design, and the numerical modeling is based on the computational fluid dynamics FVM (finite volume method) conducted in Ansys Fluent. The research comprised a set of simulations at different air flow rates of 52.5 m3/h, 105 m3/h, 210 m3/h and 420 m3/h at the enclosure inlet. The analysis carried out on the basis of flow paths and temperature distribution plots inside the enclosure led to the conclusion that the expected, analytically calculated minimum volumetric flow rate is not sufficient to effectively cool the investigated device to the required temperature of 26 °C, and higher air flow rates should be applied. Simulation results indicated that the numerical tools can be useful in the prediction of the heat exchange process, as well as in the selection of an appropriate source and location of cooling.

Sound insulation of lightweight external frame walls and the acoustic effect of additional thermal insulation

The sound insulation of lightweight frame façades and the acoustic effect of additional thermal insulation were examined. The research aimed to investigate the contribution of different insulating layers to the acoustic performance of an external wall. In particular, the use of ETICS (external thermal insulation composite systems) was considered. This usually reduces the sound insulation of traditional massive partitions substantially whereas for lightweight frame structures the effect was not precisely identified. The study is based on laboratory measurements, and several full-scale models were tested. Wood and metal frame walls with various claddings were considered. The application of ETICS caused the reduction of sound insulation in a certain frequency range. The effect, however, seems not as harmful as for massive partitions. Another type of thermal insulation with a venting cavity demonstrated much better acoustic performance. Conversely, internal installation cladding, when rigidly fastened to the basic structure had practically no effect on the wall properties. Significant improvement was observed when resilient spacers or separate supporting structures were applied.

Controlling the thermal regime of the road surface in the cryolithic zone

The thermal regime of the road surface of automobile roads in the cryolithic zone determines its reliable and safe exploitation. An important indictator of the thermal regime is the thawing depth of the road foundation (the underlying soil). The purpose of this research was to determine the influence of the Biot number, characterizing the thermal resistance of the structural layers of the road, on the thawing depth of the road surface. On the basis of simple engineering formulas, the basic qualitative and quantitative regularities of the influence of Fourier and Stefan numbers on the Biot number value which allows thawing of the road foundation up to a given depth in the warm period of the year were surveyed. 3D charts allowing to determine the required Biot number in a wide range of initial data were created. Knowing the Biot number, it is possible quickly to determine the thermal resistance and to select a fitting material for the additional thermal insulation layer for the structure of the road surface.