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

Maryam Karami,Ehsan Anbarzadeh,Shahram Delfani

doi:10.18186/thermal.1086236

Maryam Karami, Ehsan Anbarzadeh + Show 1 more

Open Access

https://doi.org/10.18186/thermal.1086236

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Abstract

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.

Highlights

It should be noted that in Abadan (Hot-semi Humid) and Bandar Abbas (Hot-Humid), the increasing trend after reaching the lowest value occurs in the lower optimum insulation thickness comparing with other cities; this is because of the lower heating load in these zones, which requires in the lower optimum insulation thickness
The effect of size variation of HVAC system by increasing the insulation thickness has been investigated at different climate zones
Using central heating system, the optimum insulation thickness with and without considering the size variation of the HVAC system in climate zones of ColdDry, Moderate-Humid, Hot-Dry, Hot-semi Humid, and Hot-Humid increases 12.3%, 12.7%, 9.5%, 14.2% and 10%, respectively

Summary

Introduction

Energy consumption is rapidly increasing due to increas- improvement in standard of living [1]. Using the energy ing population, urbanization, migration to large cities and saving methods, improving the existing technologies [2-4]. Returning to renewables [5,6] are an excellent approaches to reduce the energy consumption, which is distributed among four main sectors: industrial, building (residential/ commercial), transportation and agriculture [7]. Having 40% of all Europe’s energy consumption, the building sector is the largest energy consumer following the industrial sector and 63% of this share is assigned to residential buildings [8]. The energy required for space heating and cooling in buildings has the highest share of all and in Iran, 42% of the country’s energy is consumed in buildings [9]. The thermal insulation of building is one of the most effective methods to preserve energy and reduce energy consumption of the buildings [11]. There are many studies about determining the optimum thickness of the insulation and the parameters affecting it

Methods

Results

Conclusion