Hygrothermal Simulations of Foundations: Part 1 - Soil Material Properties

Journal Article · Tue Jan 01 04:00:00 EST 2013 · Journal of Building Physics

DOI:https://doi.org/10.1177/1744259112467526· OSTI ID:1093044

Pallin, Simon B ^[1]; Kehrer, Manfred ^[1]

---

1. ORNL

Hygrothermal performance of soils coupled to buildings is a complicated process. The computational approach for heat transfer via the ground is well defined (EN-ISO-13370:, 2007) together with simplified methods (Staszczuk, Radon, & Holm). Though the soil moisture transfer is generally ignored, it is proven not negligible (Janssen, Carmeliet, & Hens, 2004). Even though reliable material properties of soils are required to perform realistic hygrothermal calculations of soils coupled to buildings, such material properties have not been well defined in hygrothermal calculations tools. Typical building constructions which are greatly influenced by soils are basements, crawl spaces and slab on grade and reliable hygrothermal performance of such construction are highly requested; as it is ranked within the top 10 Building America Enclosure Research Ideas according to Enclosures STC - Residential Energy Efficiency Stakeholder Meeting, February 29, 2012 Austin, TX. There exists an extensive amount of measurements on soil properties in Soil Science though this information must be gathered as well as adapted to be applicable in Building Science and for hygrothermal simulation purposes. Soil properties are important when analyzing and designing both new building constructions and retrofitting measures, where the outer boundary of the buildings enclosure consists of soil materials. Concerning basement energy retrofits, interior solutions of improving the energy demand has to cooperate with the existing soil properties and must therefore be designed thereafter. In concerns of exterior retrofits, the soil material can be replaced, if needed, with a more suitable filling material, though this approach applies only for basement walls. The soil material beneath the basement floor can naturally not be replaced hence the soil properties of this part of the buildings enclosure still must be taken into consideration. This study is divided into several parts. The intention of the first part is to gather, comprehend and adapt soil properties from soil science. The obtained information must be applicable for Building Science related tasks and validated in hygrothermal calculation tools hence the second part of this study will focus on validation of the implemented soil properties. Basic changes in the software code may be requested as well. Different basement constructions will be created with a hygrothermal calculation tool, WUFI, from which simulations will be compared with existing or on-going measurements. The final outcome of the study is to enable an evaluation of several soil types in several climate zones combined with a number of basement assemblies. The study will define which type of soil together with a certain building construction which is considered most and least reliable in concerns of energy consumption and moisture safety. Further, what influences different soils will have on the total energy loss via the ground and if the performance of a different soils can be measured by a comparison of soil properties solely.

• Research Organization: Oak Ridge National Laboratory (ORNL)
• Sponsoring Organization: EE USDOE - Office of Energy Efficiency and Renewable Energy (EE)
• DOE Contract Number: AC05-00OR22725
• OSTI ID: 1093044
• Journal Information: Journal of Building Physics, Journal Name: Journal of Building Physics Journal Issue: 37(2) Vol. 37(2); ISSN 1744-2591
• Country of Publication: United States
• Language: English