Optimum insulation thickness for the sandwich structure livestock buildings external envelopes in different climate regions of China

Yang Wang,Weichao Zheng,Baoming Li

doi:10.25165/j.ijabe.20201301.5280

Abstract

Determining the optimum insulation thicknesses of external envelopes for livestock buildings are one of the most effective metrics to decrease energy requirements. This study was carried out to determine the optimum insulation thicknesses for livestock buildings in different climate zones, to examine the effects of insulation thickness and material (foam glass, mineral wool, expanded polystyrene, foamed polyurethane, foamed polyvinyl chloride, and expanded polyethylene) on life cycle total cost, life cycle savings, and payback period. The finishing pig houses and laying hen buildings with sandwich wall structures (color steel laminboard) in five typical cities were studied using the degree-days method with economic models. Optimal insulation thicknesses ranged from 0.05 m to 0.25 m and 0.02 m to 0.24 m in finishing pig houses and poultry buildings, respectively; the life cycle total costs ranged from 16.49 to 37.98 $/m2 and 13.37 to 36.84 $/m2; the life cycle savings ranged from 29.13 to 220.60 $/m2 and 0 to 202.13 $/m2; and the payback period ranged from 1.11 to 5.81 years and 1.19 to 20.76 years, respectively. Foamed polyurethane provided the highest life cycle savings, while foam glass had the lowest. In this research, the insulation thicknesses for the sandwich structure livestock buildings external envelopes are optimized, and the energy saving can be obtained by using proper insulation thickness in different regions. Furthermore, it can increase the knowledge about energy consumption in the livestock buildings and the results can be also a useful tool for farmers. Keywords: livestock building, insulation material, optimum insulation thicknesses, degree-days, life cycle total cost, life cycle saving, payback period DOI: 10.25165/j.ijabe.20201301.5280 Citation: Wang Y, Li B M, Zheng W C. Optimum insulation thickness for the sandwich structure livestock buildings external envelopes in different climate regions of China. Int J Agric & Biol Eng, 2020; 13(1): 29–41.

Highlights

Farm animals are usually kept in confined structures, the thermal comfort environment in such structures is crucial to animal’s health, welfare, and productivity
The objectives of this paper are to (i) optimize the air cooling and heating degree-days, which solar radiation was taken into consideration; (ii) analyze the optimum insulation thicknesses, energy savings, and payback periods of typical insulation materials in livestock buildings based on P1-P2 method
Yu et al.[6] calculated the optimum insulation thicknesses of five insulation materials for a typical residential wall in four cities, and the results showed that expanded polystyrene was the most economical insulation material because it had the highest life cycle savings and lowest payback period

Summary

Introduction

Farm animals are usually kept in confined structures, the thermal comfort environment in such structures is crucial to animal’s health, welfare, and productivity. Reducing livestock buildings heat loads (e.g., gain in summer and loss in winter) by optimizing the thermal insulation thicknesses of building envelopes offers an effective way to ensure thermal comfort environment and significantly decrease the energy requirements. The optimum insulation thickness computations were performed based on the heating and cooling loads and finical analysis methods[10]. Several finical methods were used to optimize the thermal insulation thicknesses of external envelopes, such as the simple payback period method, life cycle cost analysis, and P1-P2 method[8,11,12]. The simple payback period method is based on the time required to repay the initial capital investment with the operating savings attributed to that investment, and the main drawback is that it does not consider the time value of money, which is an important financial consideration[3]. Several studies used life cycle cost method to calculate the cost of a system, but this method does not take into account that additional capital is invested after the initial investment (e.g., equipment, maintenance, and operation costs)[3,11]

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Conclusion