Search Results (32)

The Life Cycle Cost Assessment (LCCA) methodology is widely used to determine the optimal thickness of thermal insulation for walls and roofs. The results depend on several factors, such as the degree day calculations method, the ambient or sol–air temperature, base temperature variations, and the heat capacity of the thermal envelope elements. This study aims to analyze the impact of solar radiation on mass walls with different orientations in five cities in northern Chile, which have severe solar climates. The goal is to determine the optimal thickness of expanded polystyrene insulation using the LCCA method, considering solar radiation, a varying base temperature, and validating results by analyzing the energy demand for heating and cooling of a typical house. The findings show that excluding solar radiation in the LCCA methodology can lead to an underestimation of the optimal insulation thickness by 21–39% for walls in northern Chile. It was also found that using variable monthly threshold temperatures for heating and cooling based on the adaptive thermal comfort model results in a slight underestimation (1–3%) of the optimal thickness compared to a constant annual temperature. An energy simulation of a typical house in five cities in northern Chile showed that neglecting the effect of solar radiation when determining the thermal insulation thickness for the studied wall can lead to a minor increase in heating and cooling energy demand, ranging from approximately 1% to 9%. However, this study emphasizes the importance of applying optimal insulation thickness for cities with more continental climates like Santiago and Calama, where the heating demand is higher than cooling. Full article

A significant portion of energy consumption in buildings is allocated to heating, with substantial losses resulting from inadequate insulation, poor sealing, and thermal bridging. While proper insulation plays a crucial role in mitigating these losses, determining its optimal thickness is essential to reduce energy consumption and increase energy efficiency. This study employs life cycle cost analysis and average heating degree day values to calculate the optimum insulation thickness for 81 provinces in Türkiye. The findings highlight the absence of a one-fits-all insulation solution, emphasizing the need for customized approaches tailored to specific conditions that consider specific factors, such as environmental conditions, heating sources, costs, economic parameters and the materials used. Proper insulation application is projected to reduce carbon emissions by 90% and lower annual heating costs by approximately 65%. These energy efficiency improvements are particularly significant for both households and businesses, enhancing profitability and competitiveness. Collaborative efforts to promote proper insulation solutions are anticipated to reallocate financial resources toward innovation and contribute to long-term business sustainability. This study provides an important framework for guiding the adoption of proper insulation practices in building design and construction. Full article

Interest in the use of container houses has been increasing in recent years because of their resistance to earthquakes and fires. The incorporation of recyclable materials into these houses will simultaneously reduce energy use and greenhouse gas emission rates. In this context, the thermal performance of an external multi-layer wall of a container house mostly made of recyclable materials is studied and compared to that of a normal wall. The current study proposes a completely new structure, where there are air gaps and plastic layers between the steel sheets to enhance thermal insulation. In these gaps, different gases including argon are tested to reduce the heat loss. Calculations are carried out for a steady-state case in the winter season using the student version of ANSYS 2023 R2 Academic software, and the heat loss is calculated for different materials and different thicknesses of the wall layers. Afterward, based on a life-cycle cost analysis, the optimum air gap materials, optimum thickness of plastic and air gap, and energy savings are determined for a period of 20 years. We found that the optimum number of plastic layers to minimize the heating load is 21, but this reduces to 11 when considering economic factors. Furthermore, if a reflective layer covers the plastic layer, the optimum is just one layer. For an insulation thickness of 2 cm, the maximum total life-cycle savings are 335.14 and 350.52 USD, respectively, and the minimum ones are 16.06 and 31.44 USD, respectively, for multi-layer walls with and without reflective layers compared to conventional walls. Full article

An optimization study on thermal insulation applied to building exteriors has been performed in this research. Solar radiation has been considered while obtaining optimum insulation thicknesses for various directions. Analyses have been conducted not only for the cardinal directions (south, north, west, and east) but also for the intermediate directions (southeast, northeast, northwest, and southwest). Solar radiation received by vertical walls and cooling and heating degree day values have been computed according to directions. This research examines the most suitable insulation thicknesses for different seasonal usage scenarios, considering cooling, heating, and annual energy demands. Variations in energy cost savings, savings rates, payback periods, seasonal energy demands, and optimum insulation thicknesses for various wall orientations have been presented. Additionally, correlations providing the total cost based on the applied insulation thickness for each direction and various building usage scenarios have been determined. The results indicate that incoming solar radiation varies from 52.08 W/m² to 111.82 W/m² across different wall orientations, while energy cost savings range from 23.48 USD/m² to 24.56 USD/m², with savings rates between 69.8% and 70.3%. Payback periods range from 5.94 to 6.05 years. Depending on the wall orientation, optimum insulation thicknesses vary between 4.52 and 5.02 cm for heating, 1.56 and 2.09 cm for cooling, and 5.92 and 6.08 cm for annual energy requirements. The heating energy demands ranged from 54.8 MJ/m² to 58.38 MJ/m², while the cooling energy demands varied between 10.91 MJ/m² and 12.08 MJ/m², depending on the wall orientation. It has been concluded that the ideal insulation thicknesses for meeting cooling, heating, and annual energy demands vary depending on the wall orientation and the building’s use purpose. Full article

Thermal insulation applications on the exterior facades of buildings have been the subject of numerous studies from the past to the present. Some of these studies focus on the cost reduction effect of insulation, while others emphasize its ecological benefits. In this study, multi-objective optimization, the objectives of which are minimum cost and minimum CO₂ emission, has been carried out with the NSGA-II method. In emission calculations, in addition to fuel-related emissions, the carbon footprint of all materials comprising the wall has also been included. The multi-objective optimization study examined four design variables: wall thickness, wall material (light concrete, reinforced concrete, and brick), insulation material (expanded polystyrene, extruded polystyrene, mineral wool, and polyurethane foam), and heating source (natural gas, electricity, fuel oil). Analyses have been carried out for four cities (Osmaniye, Bursa, Isparta, and Erzurum), which are located in different climatic regions, and considering solar radiation effects. An existing building has been taken as the base case scenario, and the study has determined the improvements in the total cost and the amount of CO₂ released into the environment when the appropriate insulation material, insulation thickness, wall material, and heating source identified in the multi-objective optimization study have been used. At the cost-oriented optimum point in the study, the most suitable insulation material was found to be expanded polystyrene, the most suitable wall material was brick, and the most suitable heating source was natural gas. In the CO₂-oriented optimum, in contrast to the cost-oriented approach, optimal results have been obtained when light concrete was selected as the wall material. Full article

The article proposes indicators to evaluate a thermal insulation investment in a building, such as net present value (NPV), profitability index, discounted payback period, and ecological cost efficiency. Economic and ecological aspects were taken into account. Life Cycle Assessment (LCA) was used in the ecological analysis. The following heat sources in the building were considered: condensing gas boiler and heat pump. The developed indicators also depend on the pre-set temperature in residential premises. A methodology to determine the optimum thermal insulation thickness for both economic and ecological reasons was also proposed. A case study was analyzed, and a reference building, typical for Polish construction conditions, was used for research. Various solutions were suggested regarding the type of thermal insulation material and heat sources. The values of the indicators were determined for the proposed variants and for the economically and ecologically optimum thermal insulation thicknesses. Based on the conducted research, it was found that air temperatures maintained in the rooms of the building undergoing thermal modernization should be taken into account in the energy audit. The energy demand of the building for a room temperature of 26 °C is higher by 61% compared to the demand for the same building at the design temperature (20 °C). The innovation in the proposed approach to the economic and ecological assessment of a building is the combination of a wide range of temperatures potentially maintained in living spaces with ecological cost-effectiveness. Full article

The main purpose of this paper is to implement a simulation model in @RISK^TM and study the impact of incorporating random variables, such as the degree days in a traditional deterministic model, for calculating the optimum thickness of thermal insulation in walls. Currently, green buildings have become important because of the increasing worldwide interest in the reduction of environmental pollution. One method of saving energy is to use thermal insulation. The optimum thickness of these insulators has traditionally been calculated using deterministic models. With the information generated from real data using the degree days required in a certain zone in Palestine during winter, random samples of the degree days required annually in this town were generated for periods of 10, 20, 50, and 70 years. The results showed that the probability of exceeding the net present value of the cost calculated using deterministic analysis ranges from 0% to 100%, without regard to the inflation rate. The results also show that, for design lifetimes greater than 40 years, the risk of overspending is lower if the building lasts longer than the period for which it was designed. Moreover, this risk is transferred to whomever will pay the operating costs of heating the building. The contribution of this research is twofold: (a) a stochastic approach is incorporated into the traditional models that determine the optimum thickness of thermal insulation used in buildings, by introducing the variability of the degree days required in a given region; (b) a measure of the economic risk incurred by building heating is established as a function of the years of use for which the building is designed and the number of years it is actually used. Full article

Optimizing the multilayer thermal insulation of pipelines transporting liquids and gases at higher than ambient temperatures is crucial for heat energy conservation and cost optimization. This study utilizes a multi-objective genetic algorithm to optimize the multilayer thermal insulation thickness around a pipe carrying fluid to minimize heat loss and associated costs. The model adopted mathematical associations between design variables and the overall installation cost of layers over a pipe from the available literature. The proposed model considered one or more insulation layers of rock wool and calcium silicate to oil pipelines containing steam, furfural, reduced crude or 300-distillate oil. All calculations considered fixed-charge rates as a fraction of 1 or 0.15. The results were compared with standard values and those predicted by other researchers in the literature. For the steam line, the standard insulation thickness was 50 mm, jumping to 327 mm for rock wool and 232 mm for calcium silicate. However, it decreased to 38 mm for double-layer calcium silicate and 138 mm for double-layer rock wool. For furfural, the insulation thickness was 40 mm, which rose to 159 mm for rock wool and 112 mm for calcium silicate. In general, for all four cases, the results show that using normal insulation thickness is inadequate and not economical. For example, for 300-distillate oil, the present practice puts the cost function at 54 USD/m, which drops to 20 USD/m for rock wool and 24 USD/m each for single-layer silicate and double-layer insulation. This amounts to almost 60% cost savings. Similar trends are observed for the other three cases. This model can provide up to 60% savings in cost and a 92% reduction in heat loss at optimum insulation thickness compared to other models. Full article

In the construction domain, there is a growing emphasis on sustainability, resource efficiency, and energy optimisation. Light-gauge steel panels (LGSPs) stand out for their inherent advantages including lightweight construction and energy efficiency. However, the effective management of thermal efficiency, particularly addressing thermal bridges, is crucial. This paper conducts a detailed numerical investigation into the thermal performance of LGSPs, examining varied insulation ratios. Thermal finite element (FE) models were initially developed using the THERM software and validated against code predictions and results available in the literature. A comprehensive parametric study explored different insulation ratios, insulation materials, and wall thicknesses, discovering their impact on thermal transmittance (U-value). Key findings revealed that U-value correlated with insulation material conductivity, with E-PLA insulation exhibiting the lowest values, and increasing wall thickness resulted in decreased U-values. It was found that a strategic use of insulation yielded a U-value reduction of over 65%. New simplified design approaches were developed, featuring insulation ratios linked to accurate U-value predictions for LGSP configurations. The new design approaches were found to provide more accurate and consistent U-value predictions. Moreover, optimum insulation ratios for new builds and existing building extensions were found to be around 0.9 and 0.7 for 275 mm and 325 mm thick walls, respectively. These proposed energy-efficient solutions, facilitated through advanced design, are well-aligned with net-zero construction objectives. Full article

In this work, aerogel renders were enhanced with fibres for use in new building walls, emphasising a Mediterranean climate. The main novelty of the study relies on an integrated evaluation of the aerogel-based fibre-enhanced thermal renders from environmental, energy and economic approaches. Therefore, optimum insulation thicknesses, life cycle savings, payback periods, abiotic depletion potential from fossil fuels (ADP-ff) and global warming potential (GWP) impacts were quantified as a function of the energy consumption. The cost optimisation of aerogel-based renders enabled a reduction from 2477.4 to 1021.7 EUR∙m⁻³ for the reference formulation, and the sisal-optimised render led to the best-integrated performance. A higher DD* (degree-days equivalent) led to higher optimum thicknesses (the Azores required 0.02 m and 0.01 m and Bragança 0.06 m and 0.03 m for cost-optimised and non-optimised thermal renders with sisal fibre, respectively). The optimum thickness related to the ADP-ff and GWP impacts was higher, 0.04 m for the Azores and 0.09 m for Bragança. A steeper decrease in the annual energy consumption occurred for thermal renders up to 0.02 m in the Azores and 0.04 m in Bragança. Aerogel-based fibre-enhanced thermal renders had benefits, mainly from 600 DD* onwards. Full article

The current climate change context raises the demand for reducing energy and environmental impacts while keeping an economic balance and building users’ comfort. Thermal insulation solutions are potential allies in ensuring the adequacy of existing buildings for challenging sustainability requirements. In this scenario, silica-aerogel-fibre-based thermal renders are innovative solutions for which integrated approaches still lack information, and they should be compared with benchmark multilayer solutions, such as those based on expanded polystyrene (EPS), extruded polystyrene (XPS), mineral wool (MW), and insulated corkboard (ICB), to evidence their prospective economic, environmental, and energy benefits. This paper quantifies the optimum insulation thicknesses, life cycle savings, payback periods, and environmental impacts of innovative thermal renders compared to conventional thermal insulation materials when applied as a retrofit in existing facade walls. The results show that cost-optimised thermal renders with sisal fibres led to the best overall performance. Higher heating needs led to higher optimum render thicknesses and life cycle savings. With a 0.02 m thickness, aerogel-fibre-based thermal renders outperformed other materials in terms of heating-degree days (HDD) from 1000 °C·day onwards; they can save approximately EUR 60∙m⁻², 1000 MJ∙m⁻², and 100 kg CO₂ eq∙m⁻² while presenting a U-value 13% lower throughout their 30-year lifetime when compared with the second-best multilayer solution with XPS. Full article

The global demand for mineral resources has led to the gradual transformation of the mining industry from the traditional shallow, small-scale mining mode to the high-intensity mining of deep underground mines. Due to the high stress, high temperature, high permeability, and easy disturbance of deep mines, new challenges have been brought to the mining of materials. Some scholars have improved the thermal insulation performance of concrete by adding low thermal conductivity materials such as ceramsite, shell, and natural fiber to traditional shotcrete, but there are still high costs, insufficient support strength, and unsatisfactory thermal insulation effects. Given the background related to the fact that it is still not possible to fully recycle the large amount of solid waste generated by mining activities, this paper, with traditional shotcrete as its basis, uses coal fly ash to replace part of the cement and tailings to replace part of the sand and gravel aggregate. In addition, it adds basalt fiber to reduce thermal conductivity and restore strength. An orthogonal experiment of three factors and three levels was designed to explore a new type of solid waste-based thermal insulation support shotcrete material. Through the testing and analysis of the mechanical and thermal properties of the specimens, it was concluded that the optimal ratio of the materials was 45% fly ash, 50% tailings, and 25% basalt fiber (the percentage of the total mass of fly ash and cement). The compressive strength of the specimens after curing for 28 days could reach 16.26 MPa, and the thermal conductivity and apparent density were 0.228561 W/(m·k) and 1544.00 kg/m³, respectively. By using COMSOL Multiphysics multi-physics coupling software to analyze the coupling of the stress field and temperature field, it was concluded that the optimum thickness of the thermal insulation layer of this material was 150 mm. The field application in a mine in Shandong Province proved that it met the effects of thermal insulation (the ability to isolate heat conduction) and support. The successful trial of this material provides a new idea for the solving of the problem of heat damage and solid waste utilization in deep mines, which has a certain practical significance. Full article

Bio-based composites are increasingly used. One of the most frequently used materials is hemp shives, which is agricultural waste. However, as the quantities of this material are lacking, there is a tendency towards finding new and more available materials. Corncob and sawdust are bio by-products that have great potential as insulation materials. In order to use these aggregates, it is necessary to examine their characteristics. New composite materials based on sawdust, corncobs, styrofoam granules, and the mixture of lime and gypsum as the binder were tested in this research. This paper presents the properties of these composites obtained by determining the porosity of samples, volume mass, water absorption, airflow resistance and heat flux, which was followed by the calculation of the thermal conductivity coefficient. Three of the new biocomposite materials, whose samples were 1–5 cm thick for each type of mixture, were investigated. The aim of this research was to analyze the results of different mixtures and sample thicknesses in order to determine the optimum composite material of the proper thickness so that the best possible thermal and sound insulation could be obtained. Based on the conducted analyses, the biocomposite with a thickness of 5 cm, composed of ground corncobs, styrofoam, lime, and gypsum, proved to be the best in terms of thermal and sound insulation. New composite materials can be used as an alternative to conventional materials. Full article

Improvement of the energy efficiency of buildings contributes to energy savings. It is obvious that thermal modernization of a building reduces the demand for energy needed to heat it. The energy demand itself also depends significantly on the temperature maintained inside the building. The article proposes a methodology for determining the economic and ecological benefits of thermal insulation of a building and the optimal thickness of thermal insulation depending on the pre-set temperature. The analysis includes various types of heat sources and materials used for thermal insulation. A range of pre-set air temperature values in residential premises from 17 °C to 26 °C was analysed. Determining the optimal thickness of the external walls, in accordance with the preferences of building users, even at the level of designing the thermal insulation of the building, is of significant importance for economic and ecological benefits. The optimum thickness of thermal insulation in the case of the ecological assessment was much higher in each variant than in the case of the economic assessment. Full article

Cold storage facilities consume a considerable amount of energy, especially in hot climates, which can be decreased using thermal insulators to maintain a stable temperature. The primary aim of this research study was to determine the effect of insulation thickness on the energy efficiency and cost savings of exterior walls for cold storage facilities in all climatic zones of Türkiye. To this end, data from the meteorological databases of 81 provinces were analyzed, and four insulation materials (expanded polystyrene, extruded polystyrene, rock wool, and polyurethane) were selected for different cold storage reference temperatures. The spatial distributions of optimal insulation thickness, energy savings, and payback periods were derived using a geographic information system (Ordinary Kriging). The optimum insulation thickness and energy savings were found to be 0.020–0.137 m and 0.030–6.883 USD/m², respectively. Depending on the insulation material and base temperature, the shortest payback periods (1.498–3.457 years) were obtained in the Aegean and Mediterranean regions. In addition, rock wool provided the highest energy savings and the shortest payback period among all the insulation materials studied. The results from this study can help investors to improve their design considerations for cold storage wall insulation. Full article