Potential Thermal Enhancement of Lightweight Building Walls Derived From Using Phase Change Materials (PCMs)

Xiaoqin Sun,Yuan Zhang,Mario A Medina

doi:10.3389/fenrg.2019.00013

Abstract

This paper presents results of the potential thermal enhancement in building walls derived from using phase change materials (PCMs). Typical North American construction, namely, frame walls outfitted with hydrated-salt-based PCM were evaluated in well-controlled test houses under full weather conditions. It was found that PCMs produced reductions in energy gains during summer. The reductions were assessed via total heat transfer and peak heat transfer. For a 10 percentage by weight (wt%) PCM concentration, the largest peak flux reduction of 31.25% was observed when the PCM was integrated within a north-facing wall. For a 20 wt% PCM concentration, the largest peak flux reduction was 25.54% when the PCM pipes was installed on an east-facing wall. Doubling the amount of PCM did not produce improvement on heat flux reduction except for the east-facing wall. The indoor wall surface temperature and temperature amplitude was reduced by 1.5 oC and 1.4 oC, respectively. The maximum time lag for peak heat flux was observed on the north-facing wall, which was 1.5 hours for a 10 wt% PCM concentration and 2.25 hours for a 20 wt% PCM concentration, respectively. To achieve the maximum energy savings, it is recommended that the PCMs be installed within west-facing walls.

Highlights

Buildings are responsible for about 40% of US energy consumption
The results showed that the internal wall surface temperature was reduced by 2◦C
Heat transfer through frame walls with phase change materials (PCMs) encapsulated in copper pipes were investigated in well-controlled test houses under full weather conditions

Summary

Introduction

Buildings are responsible for about 40% of US energy consumption. They are the major source of green gas emission as a result of their energy and material demands. To accomplish the proposed Architecture 2030 Challenge it is important to reduce a part of this energy consumption. The integration of phase change materials (PCMs) to building walls has proven to be an effective method to reduce heat transfer through building enclosures and shift a part of the peak load to other times of the day (Kosny et al, 2007, 2012a,b, 2014; Konuklu et al, 2015; Guldentops et al, 2018; Song et al, 2018). PCMs work by storing relatively large amounts of heat when melting without

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Conclusion