Contrasting climate-based approaches and building simulations for the investigation of Earth-to-air heat exchanger (EAHE) cooling sensitivity to building dimensions and future climate scenarios in North America

Abstract

Evolving cooling needs have promoted the examination of passive low energy cooling solutions such as Earth-to-air heat exchangers (EAHE). These systems heat or cool passing air based on the seasonal air-soil temperature differences, therefore exhibiting a natural correlation between system performance and climate. Key performance indicators (KPIs) of EAHE cooling potential generated from climatic indicators were compared to building simulation results, for a multitude of system and building configurations, baseline cooling thresholds, and future climate scenarios to identify sensitivity of these indices useful for pre-design evaluations. The analysis was conducted for nine representative locations in North America. Using weather files representative of future climate scenarios, the potential for EAHE cooling was shown to persist in cooler climates in contrast to cooling dominated regions like Miami and Phoenix whose use of the EAHE was not effective. In terms of building and system design, shading and control natural ventilation (CNV) were identified as the ideal additions to promote EAHE cooling. Mean soil temperature was also identified as a possible metric for estimating EAHE cooling as cooler soil temperatures expectedly perform better. The comparison between the two approaches demonstrated climate indicators consistently reflected the behaviour predicted by building simulation despite changes to building dimensions. As a result, climate indicators have been shown to be effective pre-design tools in estimating EAHE cooling potential. These can be used by stakeholders evaluating the benefit of EAHEs in providing sustainable cooling in various climates and future climate conditions.