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

Abstract

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.

Thermal Performance of Residential Roofs in Malaysia: Experimental Study Using an Indoor Solar Simulator

“…In tropical countries, building sectors consume roughly 57% of the nation's total electrical energy, and 60% of the electrical energy in the building sector is from air conditioning systems [5]. Past research proves that roof insulation is an effective passive cooling method to reduce heat intake through the roof and reduce building energy consumption [6].…”

Assessment of Energy, Environmental and Economic Costs of Buildings’ Thermal Insulation–Influence of Type of Use and Climate

“…The methodologies used to identify the best thermal insulation material, its better position in the building opaque envelope, and its optimal thickness are normally based on a life cycle energy analysis (LCEA), a life cycle impact analysis (LCIA), and a life cycle cost analysis (LCCA), depending on whether the focus is on minimizing the energy consumption, the environmental impacts, or the economic costs, respectively [7][8][9][10][11][17][18][19][20][21]. As the relationship between the economic cost of buildings' thermal insulation and its energy efficiency and environmental impacts is not linear, there may be large differences between the solutions identified as the best, depending on the assessment methodology used [11,12,[17][18][19][20][21].…”

“…It was assumed that all buildings are built using the same type of passive construction solutions (opaque and glazed), and the opaque elements of the buildings' envelope are equipped with a traditional External Thermal Insulation Composite System (ETICS) [2,11,24,25,[28][29][30][31][32]. The three most common thermal insulation materials used in building construction are expanded polystyrene (EPS), extruded polystyrene (XPS), and mineral wool (MW) [20,21,30,33,34]. Thus, these are the insulating materials considered.…”

“…The thermal insulation materials most commonly used in building construction are expanded polystyrene (EPS), extruded polystyrene (XPS), and mineral wool (MW) [11,16,17,20,21,30,33]. The option for these materials is a result of their economic advantages, which is the first criterion used by the constructors and the owners of buildings.…”

Calculation of Insulation Thickness Depending on The Coolest and Hottest Climate Conditions for Different Flat Roof Types of Buildings

“…For this purpose, a computer model based on finite differences under various stable periodic conditions is used in the study (De Rosa et al, 2014). Wang et al (2022) determined the roof thermal insulation type and optimum insulation thickness. They presented an optimization design method based on an integrated economic and environmental consideration for the best insulation design on building roofs.…”