Optimum Insulation Thickness Research Articles

Effect of insulation thickness on energy saving in cold regions of Türkiye

In the countries procuring a major amount of their energy from abroad, using of the energy effectively and ensuring the energy-saving become gradually more important. In this study, considering the climatic and meteorological conditions of Van province, optimum insulation thickness, payback period, and energy-saving values were analyzed for three insulation materials (rock wool, polyurethane, XPS) and five energy sources (imported coal, fuel oil, LPG, natural gas and electricity) on wall models built with pumice and aerated concrete. The optimum insulation thickness was calculated using the interest and inflation rates. The calculations were made by making use of the lifecycle cost analysis (LCCA). Insulation thickness that should be applied depending on the wall elements used in buildings can vary. Thus, examining the wall models, insulation materials and energy sources were examined, and the optimum insulation thicknesses, annual savings, and payback periods were found to be 3-15.6 mm, 30-63%, and 1.4-5.8 years, respectively, in the present study.

Impact of insulation materials and wall types of reference buildings on building energy efficiency with three methods in Çorum city

AbstractThe improvement of energy efficiency in buildings is one of the most important factors of the energy policy of Turkey owing to its energy import, especially of natural gas. Çorum city, one of the colder cities of Turkey that uses a high amount of natural gas as fuel for heating, was selected to demonstrate the reduction in energy loss and carbon dioxide emissions of buildings and to contribute to the insulation sector in the Çorum industry. Therefore, two different methods, namely, the Turkish standard 825 and heating degree‐days, are applied in cost‐optimal methodology, using four types of traditional insulation materials, namely, standard expanded polystyrene, neopor (graphite‐added expanded polystyrene), extruded polystyrene, and stone wool, and two state‐of‐the‐art insulation materials, aerogel and vacuum insulation panels in two types of reference buildings comprising hollow brick and pumice stone walls. As a consequence of application of the Turkish standard 825 and heating degree‐days methods in the cost optimal methodology of the European Energy Performance of Buildings Directive with the utilization of the optimum insulation thicknesses of six types of insulation materials calculated from both the Turkish standard 825 and heating degree‐days methods at four different types of windows and one top side measure, a new methodology was developed. Results obtained from three methodologies are compared based on insulation materials and wall types.

A carbon-focus parametric study on building insulation materials and thicknesses for different heating systems: A Swiss case study

To tackle the problem of climate change, Swiss energy strategies aim to reach the carbon neutrality by 2050. However, this challenge cannot simply be solved by focusing on the operational energy performance and instead, on a lifecycle evaluation. Thus, in order to reduce the sector’s carbon footprint, building stakeholders need to consider embodied GHG emissions of construction materials. In this study, a parametric method was developed to balance operational and embodied impacts of insulation strategies on GHG emissions according to the material and heating system choices. The methodology is split into two for the computation of the overall carbon emissions of the heating plus insulation system. Firstly, the calculation of the embodied emissions, which relies on Environmental Product Declarations of different construction materials. Secondly, the calculation of the operational emissions, which is the product between the thermal energy needs and the energy carbon content of the respective heating system. Thereafter, the methodology was applied to two case studies: an existing building and a brand-new building. The first main finding was that, for high-carbon insulation materials, there was clearly an optimal thickness after which, adding insulation would only increase the lifecycle impact of the system. For instance, in the heat-pump equipped case study, installing 35 cm of extruded polystyrene insulation (XPS) is more harmful towards global warming than installing 17 cm of XPS. This trend was not present for low-carbon materials whatsoever. The building’s carbon emissions benefitted from their addition of insulation up to the maximum thicknesses studied. To conclude, it is also important to highlight that aimlessly targeting energy efficiency can be a step back towards the goal of carbon neutrality. Indeed, it is possible to claim that for energy efficient buildings, fossil fuel-based insulation should be carefully used. This study allowed the development and application of a method that identifies optimal insulation thickness and material for a given heating system and hopefully, highlight the importance of considering both embodied and operational emissions of construction materials and systems.

A Tool for Calculating the Building Insulation Thickness for Lowest CO2 Emissions—A Greenlandic Example

Increased insulation reduces the energy needed during operations, but this may be less than the energy required for the extra insulation material. If so, there must be an optimal insulation thickness. This paper describes the development of a tool to determine the optimal insulation thickness, including what parameters are decisive, and presents some results along with a discussion of the success criteria and limitations. To make these considerations manageable for regular practitioners, only the transmission heat loss through walls is calculated. Although the tool is universal, Greenland is used as an example, because of its extreme climatic conditions. The tool includes climate change, 10 locations and 8 insulation materials. It focuses on greenhouse gas emissions, considers oil and district heating as heating sources, and evaluates four different climate change scenarios expressed in terms of heating degree days. The system is sensitive to insulation materials with high CO2 emissions and heating sources with high emission factors. This is also the case where climate change has the highest impact on the insulation thickness. Using the basic criterion, emitting a minimum of CO2-eq, the Insulation Thickness Optimizer (ITO), generally identifies higher insulation thicknesses as optimal than are currently seen in practice and in most building regulations.

Determination of the Effect of the Change in the Thermal Conductivity Coefficient of EPS Depending on the Density and Temperature on the Optimum Insulation Thickness

Determination of the Effect of the Change in the Thermal Conductivity Coefficient of EPS Depending on the Density and Temperature on the Optimum Insulation Thickness

Optimal insulation’s thickness of pipes in Variable Refrigerant Flow (VRF) system—An-Najah Child Institute as a case study

Buildings use a significant amount of the world’s total primary energy, particularly in heating and cooling systems. Energy consumption of air conditioning systems can be lowered by installing energy-efficient systems that take into account piping thermal insulation. The objective of this research is to calculate the optimal thickness of insulation for piping networks with variable refrigerant flow and to investigate the environmental and economic impacts of using the optimal insulation thickness. The case study of this research is An-Najah Child Institute. The research is based on the current cost over the life cycle of the insulation, which is assumed to be 15 years, to determine the optimal thickness of the common insulation types (rock wool, extruded polystyrene, and flexible foam) for different pipe diameters and different refrigerant flow rates. The research results show that the optimum insulation thicknesses for pipe diameters from 12.7 to 50.8 mm using Rockwool are 32 to 44 mm, 28 to 38 mm for extruded polystyrene, and 11to 13 mm for flexible foam insulation. The reduction in energy losses from the optimal Rockwool insulation thickness in the case study piping system ranges from 78.5% to 81.6% compared to the uninsulated insulated piping system. In addition, the carbon emission saving by the optimal Rockwool insulation thickness is 1737, 1541, 1033, and 1160 kg CO2 for coal, oil, natural gas, and LPG fuel used in electricity generation, respectively. In addition, the study found that the physical parameters of the refrigerant, such as quality and flow rate, do not affect the optimal insulation thickness for all insulation types studied. And the thermal power saved corresponds to only 1.2% of the total system capacity

Optimization insulation thickness and reduction of CO2 emissions for pipes in all generation district heating networks.

District heating systems are provided solutions for the increasing energy problems in high-population cities. Energy costs go up depending on increasing heat loss in DHS's distribution network. Heat loss from the network consists of 5-20% of transferred energy, and this loss is higher than the other losses in the heating system. In the study, heat losses from the pipes such as supply-return pipes, hot water and circulation pipes into heat canals are investigated based on energy, exergy, economic and environmental. Optimum insulation thicknesses, energy savings, reduction of CO2 emissions, the first investment costs and payback periods of the pipes in the network of all-generation district heating systems are investigated by using Life Cycle Cost Analysis (LCCA) method for fuel types like natural gas, fuel oil and coal. Optimum insulation thicknesses are calculated for different nominal sizes of pipes and various insulation materials such as glass wool, and rock wool for the different climatic zones. According to the results of the study, the heat losses from pipes in the 4th generation DHS network are decreased between 38.19% and 33.33% from the warmest climate zone to the coldest climate zone according to the 3rd generation. Energy savings, reduction of CO2 emissions, payback periods and optimum insulation thickness values of supply and return pipes in the network are respectively changed between 7.80-98.86 $/m, 39.61-322.32 kg CO2/year, 0.028-0.38 years and 0.025-0.0105 m depending on various fuel types, insulation materials, nominal size pipes, climatic zones and all generation types.

Integrated Economic and Environmental Assessment-Based Optimization Design Method of Building Roof Thermal Insulation

The design of thermal insulation in roofs is very important to reduce energy consumption and decrease the environmental impacts of buildings. An integrated economic and environmental assessment-based optimization design method is presented in this paper to find the best candidate insulation design scheme for building roofs, including the determination of roof thermal insulation type and the optimum insulation thickness. In the optimization design method, a zonal method-based double-skin ventilation roof heat transfer model is developed to predict the roof energy consumption. Economic and environmental benefits due to thermal insulation are calculated by using the economic analysis model, the environmental analysis model, and roof energy consumption. Moreover, an integrated dimensionless economic and environmental assessment index is proposed to evaluate different roof thermal insulation design schemes. The optimum insulation thickness is determined by maximizing the sum of economic benefit and environmental benefit due to thermal insulation. The validation results in a real building show that the predicted data for the zonal-based double-skin ventilation roof heat transfer model agreed well with the measured data, with a maximum relative error of 8.2%. The optimum insulation thickness of extruded polystyrene (EPS), mineral wool (MW), and polyurethane (PU) was between 0.082 m and 0.171 m for the single-skin roof in a low-temperature granary in Changsha region in China. The ranking of the integrated assessment indexes of thermal insulation is EPS > MW > PU. A double-skin ventilation roof can reduce the optimum thickness of thermal insulation. The best result is obtained by EPS for the double-skin roof with a grey outer surface color for the low-temperature granary roof in Changsha region in China. The influencing factors of insulation type, roof structure, and roof outer-surface color should be considered in finding the best candidate insulation design solution for building roofs. The integrated economic and environmental assessment-based optimization design method can help designers to efficiently find the best design scheme of thermal insulation to maximize the sum of economic benefit and environmental benefit for building roofs.

ОПТИМАЛЬНАЯ ТОЛЩИНА ТЕПЛОВОЙ ИЗОЛЯЦИИ

The method of determining the optimal thickness of thermal insulation from the condition of minimizing the unit annual costs is considered

A Study on Optimum Insulation Thickness in Walls of Chinese Solar Greenhouse for Energy Saving

Chinese solar greenhouses (CSGs) are characterized by unique walls to reduce the transmission of heat and promote the energy conservation in winter production, which promotes cultivation in the northeast region of China in winter. Effective selection of insulation material is important for the CSG based on the energy consumption and economic analysis. However, choosing the thickness of the insulation material in walls often discussed with the structure of CSG. There is a lack of research combing the optimal insulation thickness for improving the energy conservation. The aim of this study was to find the optimum insulation thickness during the energy conservation based on the structure of walls, the energy consumption in local climatic conditions, the cost of insulation material, and economic payback period over a lifetime. By the economic analysis of insulation thickness, thermal resistance, lifetime energy saving, and payback period, three kinds of typical walls (clay brick (CB), hollow concrete block (HCB) and fly ash block (FAB)) combed with four insulation materials including the expanded polystyrene, the foamed PVC, the perlite, and the rock wool were calculated. The optimum insulation thickness can be found when energy savings reached the maximum. In the northeast region, the association of FAB with rock wool as the insulation layer was the most economic composite wall structure. The optimum insulation thickness was 0.05 m, with the cost only 5 USD/m2. The thermal resistance of composite wall had a significant effect on the payback period. When thermal resistance increased from 0.2 to 1.2 m2K/W, the payback period varied from 0.4 to 4.3 years. What is more, the energy consumption in local climatic conditions had a more significant effect on payback period. It can be assumed that insulation materials are more favored in cold climatic regions where heating degree-days over 1600 °C days for payback periods is less than 2 years. These results have strong practical and economical significance in saving energy and improving the environment of CSG.

SICAK İKLİM ŞARTLARI ALTINDA İÇ DİZAYN SICAKLIĞI, TERMAL ÖZELLİKLER VE YALITIM KALINLIĞININ BELİRLENMESİ

The base purpose of this work is to use interior design temperatures and the heating and cooling periods, which are determined according to different wall orientations in terms of thermal performance throughout the year, in the calculation of heat transfer characteristics and optimum insulation thickness. This work is realized under dynamic thermal conditions for the climatic conditions of Adana, Turkey. Firstly, the transmission loads for both heating and cooling are determined for uninsulated and insulated walls according to indoor design temperatures: 20, 22, 24 oC. Annual transmission loads, annual average dynamic thermal resistance, annual average time lag, and decrement factor for various wall directions are calculated by using indoor design temperatures determined over the whole year from minimum heating and cooling transmission loads point of view. Then, these loads determined overheating and cooling periods are used for the optimization of insulation thickness. In the uninsulated wall, yearly cooling load is obtained to be 221.37, 152.81, 229.14 and 229.14 MJ/m2 for the south, north, east and west orientations, respectively while yearly heating load is obtained to be 73.54, 138.44, 117.62 and 117.62 MJ/m2. It is observed that the cooling load is more dominant than the heating load under the climate conditions of Adana. It is also observed that the longest cooling period is obtained in south orientation while the shortest cooling period is obtained in north orientation. The optimum thickness of the insulation for Adana is obtained to be 8.4, 8.0, 9.2 and 9.2 cm for south, north, east and west orientations, respectively. The results indicate that the indoor design temperatures and insulation have a significant effect on heating, cooling and total transmission loads. Besides, the results reveal that the wall orientation has an important effect on heating and cooling periods, dynamic thermal resistance, time lag and optimum insulation thickness.

The Effect of External Wall Insulation on Mold and Moisture on the Buildings

In this study, mold and moisture risk of external walls were investigated based on the six different wall types (block bims 1-2-3-4, hollow brick, and aerated concrete) and three different insulation materials (hemp wool, aerogel blanket, and extruded polystyrene). During the examinations, uninsulated and insulated external walls were taken into account according to moisture and mold growth depending on dew point temperatures. While calculating the optimum insulation thickness for uninsulated wall, degree-day and life cycle total cost methods were used. The natural gas, coal, and electricity were accepted as an energy source for heating and electricity was used for cooling. In the study, Izmir, Balikesir, Ankara, Kayseri, and Erzurum cities were selected to represent five climate zones according to Turkish insulation standard (TS 825). As a result of the calculations, the highest values of optimum insulation thickness were found in hemp wool and hollow brick for the electricity energy sources. It was determined as 0.118 m in Izmir and 0.202 m in Erzurum. For the insulated wall, the lowest indoor humidity value, where mold and moisture formation occur, was determined as 78% for Izmir and 69% for Erzurum.

Effect of thermal insulation on building energy efficiency in Turkey

In light of the current energy problems, building envelopes must achieve thermal insulation in buildings by consuming the least amount of energy, thereby minimising energy consumption. This study determined the optimum insulation thickness of external walls, ceilings and floors of buildings as well as energy saving and payback periods in 81 city centres in Turkey. The calculations were performed for commonly used walls, ceilings and floor constructions. The life-cycle cost analysis and Turkish standard TS 825 (‘Thermal insulation requirements for buildings’) were also considered. In the calculations, the decreasing factor applied in TS 825 for surfaces that have no contact with outer air was considered. The results showed that the optimum insulation thickness of the external walls, ceilings and floors ranged between 3.5 and 20.0, 4.6 and 19.7 and 0.7 and 14 cm, respectively, depending on the type of energy and insulation material used. These findings suggest the possibility of saving up to 75% energy on the external walls, 90% on the ceilings and 85% on the floors. Additionally, a saving of 12–13% is likely obtainable in Turkey's total energy consumption when the optimum insulation thickness is applied to all residential buildings in the country.

A study on influencing factors of optimum insulation thickness of exterior walls for rural traditional dwellings in northeast of Sichuan hills, China

Thermal performance of exterior walls can be improved with increasing insulation thickness, but the corresponding material cost will also rise. Therefore, the optimum thickness of insulation material necessarily exists when the economy is considered. Adding insulation materials with the optimum thickness for exterior walls of rural traditional dwellings in northeast of Sichuan hills can effectively enhance their thermal performance and lighten the economic burden of residents while decreasing energy consumption. Hence, the optimum thickness of five insulation materials was calculated by using the degree-days method and P1-P2 economic model as well as the energy-saving and economic benefits were evaluated based on EnergyPlus and dynamic investment payback period model. Then the influence law and the impact degree of influencing factors on the optimum thickness were analyzed via orthogonal test and analysis of variance. Eventually, the remarkable energy-saving and economic benefits of modifying the most crucial factor (heating-degree day) were assessed. Results show that the optimum insulation thickness ranges from 0.081 m to 0.144 m under the local climate and economic context. Besides, rationally lowering the heating-degree day can increase the energy-saving rate and economic benefits by 29.5% and 78.2%, respectively. The results can provide some new insights into the energy-saving retrofit of local traditional dwellings.

Wall Energy Loss and Entropy Generation in Solar Ponds Using One-Dimensional and Two-Dimensional Transient Analyses

Abstract In this paper, wall thermal energy loss in a cylindrical solar pond is studied using one-dimensional (1D) and two-dimensional (2D) transient models. It is seen that for a given quantity of insulation applied around the pond wall, the negative effect of sidewall loss reduces as the pond size increases. Further, the optimal insulation thickness that eradicates all wall energy loss is larger when calculated from a spatially 1D model, as opposed to when radial temperature gradients are given consideration. The 2D model reveals a larger entropy generation than that calculated by a 1D model for an imperfectly insulated pond. So, for such ponds, the present model would calculate entropy generation in a more realistic manner. It is revealed that using simpler 1D in space models to estimate solar pond’s outer wall optimum insulation thickness will not lead to any problems as far as the thermal performance is the concern. But, since such models over predict the optimum value, they would invoke more cost. So, when financial and space constraints are present, then it is advisable to design the wall insulation in solar ponds using spatially multi-dimensional heat transfer models, for which the present work could prove to be useful.

Effect of HVAC system size on the optimum insulation thickness of the buildings in different climate zones

Thermal insulation is one of the most effective methods of reducing energy consumption in buildings. Therefore, the parameters influencing the optimum insulation thickness are widely investigated. In this study, the optimum insulation thickness is obtained using the life cycle analysis method and the genetic algorithm by considering the size of the heating and cooling systems as an optimization variable, which has not been addressed in the earlier researches. Furthermore, the effect of the climate conditions on the optimum insulation thickness is comprehensively studied using five different climate zones, including Hot-Dry, Cold-Dry, Moderate-Humid, Hot-semi Humid, and Hot-Humid. It is found that the optimum thickness of expanded polystyrene insulation increases between 5%-19% considering the size variation of the heating systems including the central heating system and wall-hung gas boilers. By size variation of the cooling systems including the evaporative cooler and split air conditioner, this increase is between 8-19%. This is because the cost reduction due to the reduction of the required size of the heating and cooling systems can be expended for insulating the building with larger thickness which results in lower energy consumption. Based on the obtained results, the energy cost saving increases between 3.5%-14.5% and also, the payback period decreases about 1 to 3 months, depending on the considered heating and cooling systems and climate zone. The results confirm that the optimum insulation thickness can be determined with significant inaccuracy, ignoring the size variation of the heating and cooling systems as a result of thermal insulation.

Merkezi Isıtma Sistemlerinde Yerüstü ve Yeraltı Ön Yalıtımlı Boruların Optimum Yalıtım Kalınlığı, Enerji Tasarrufu ve Yakıt Emisyon Hesabı

Enerji ihtiyacının her geçen gün arttığı dünyamızda enerjiyi verimli kullanmak çok önemli bir hale gelmiştir. Enerji verimliliğinde en etkin yöntemlerden biri de ısı yalıtımı uygulamalarıdır. Bu çalışmada merkezi ısıtma sisteminde yer üstü ve yer altı olmak üzere iki farklı ön yalıtımlı borulama sistemi için 50, 100, 200, 400, 600, 800 ve 1000 mm boru çaplarında ikinci yalıtımın optimum yalıtım kalınlığına bağlı ekonomik ve çevresel etkiler hesaplanmıştır. Hesaplamalarda derece-gün yöntemi kullanılmıştır. Hesaplamalar için Balıkesir ili seçilmiştir. Yalıtım malzemesi olarak XPS ve taş yünü, yakıt türü olarak ise doğalgaz, kömür ve fuel-oil kullanılmıştır. Çalışmada yaşam döngüsü maliyet (YDM) analizi kullanılarak 10 yıllık ömür süresi için hesaplamalar yapılmıştır. Yer üstü borulama sistemlerinde tüm parametreler değerlendirildiğinde optimum yalıtım kalınlığı 5,4 cm ile 15,3 cm arasında, yer altı borulama sistemi için ise 5,1 cm ile 12,8 cm arasında değiştiği hesaplanmıştır. Enerji tasarrufu yer üstü borulama sistemi için 8,69 $/m-yıl ile 281,33 $/m yıl arasında, yer altı borulama sistemi için 6,26 $/m-yıl ile 72,43 $/m-yıl arasında hesaplanmıştır. CO2 emisyonu yer üstü borulama sistemi için 2,1 kg/m ile 33,06 kg/m arasında, yer altı borulama sistemi için ise 2,04 kg/m ile 32,14 kg/m arasında gerçekleşmiştir. SO2 emisyonu yer üstü borulama sistemi için 0,011 kg/m ile 0,088 kg/m arasında, yer altı borulama sistemi için 0,011 kg/m ile 0,086 kg/m arasında değişmektedir.

Optimal insulation thickness of walls using improved Particle swarm optimization

Uninsulated external walls and inappropriate insulation of buildings are the main reason for energy losses. In this study, novel configurations of multi-layer pre-fabricate wall elements were used to enhance the ability of energy-saving and decrease the payback periods and investments in residential houses in five cities in Iran with different energy demands. Also, an optimization strategy is applied to determine optimum insulation thickness for external walls. The evaluation process is based on using natural gas and electricity in Iran’s buildings for heating and cooling, respectively. The optimum required insulation thickness in Cities with different climates according to their degree/day value for four different insulation materials (extruded polystyrene, glass wool, rock wool, and polyurethane) is achieved using a novel optimization method (Improved PSO). According to the obtained results, annual cost saving for of the wall in case of simultaneous heating & cooling is more than cooling and heating alone. However, for the payback period, simultaneous heating & cooling has a lower payback period than cooling and heating alone. The results revealed that the cost of rock wool is higher, and the cost of polyurethane is higher than the cost of all other insulating materials in Ardabil. Also, the optimal insulation thickness for the Ardabil city with hollow brick walls and heating and cooling needs is and for the XPS, respectively.

Utilization of biodegradable novel insulating materials for developing indigenous solar water heater for hill climates

Conventional flat plate collector based solar water heating systems use glass or ceramic wool as insulating materials to minimize the heat losses. The utilization of these inorganic insulating materials, is associated with risk in the industrial workplace activities, manufacturing, and installation depending on the exposure to the material. Thus, it is important to use and develop biodegradable organic insulating materials which are easily available, low cost and environment friendly. This study presents the design and fabrication of a flat plate collector solar water heating system using biodegradable forest and agriculture wastes as insulating material. The utilization of pine needles and rice husk as thermal insulation for the fabrication of solar water heaters is the novelty of the study. The innovative solar water heater is tested under different outdoor climatic conditions. Maximum hot water temperatures between 52 °C and 55 °C were observed with an average efficiency of 52% and 57% with rice husk and pine needles as insulating materials respectively. Experimental analysis is performed using 40 mm, 60 mm and 80 mm pine needle insulation. The optimum pine needles insulation thickness is found to be 60 mm with a maximum hot water temperature of 64 °C for the indigenously developed flat plate collector based solar water heater for hill climates. Follow-up research areas are also identified.

Pipe Insulation Evaluation for Low-Temperature District Heating Implementation in South Korea

Future energy systems will comprise 100% renewable energy and involve high integration of energy systems. District heating (DH) and cooling systems will be an undeniable part of future energy systems, as they facilitate high-efficiency, low-cost, and clean production. Low-temperature district heating (LTDH) is one of the candidates for future district heating systems, where the supply temperature is 60°C or below. Reducing heat losses from the pipe network in DH systems is challenging. Improving the insulation standards in DH pipes can decrease heat and temperature losses in the pipe networks. This study employs computational fluid dynamics to evaluate the optimum insulation thickness based on the material and digging costs in South Korea. A micro hybrid DH system with natural gas run fuel cell, heat pump and solar thermal is proposed in this study. An evaluation of the system with a 500 m pipe network system supplying hot water at 60°C with polyethylene, ethylene propylene diene monomer rubber, and polyurethane as insulation materials using ANSYS Fluent 17.2 shows that the heat losses are minimal when using PU foams. A cost estimation analysis showed that 32 mm was the optimum insulation thickness for achieving heat losses below 20 W/m and minimum material and digging costs when burring the pipeline network in the ground.