Planning Visit for Numerical and Experimental Investigation of Geothermal Heat Pumps

University Of Illinois At Chicago, Chicago IL

Investigators

Abstract

Geothermal heat pumps and heat piles are energy efficient means to heat and cool buildings. Heat piles are embedded in existing foundation elements, which generally store and conduct heat better than the surrounding soil. Geothermal heat pumps, on the other hand, are embedded directly in the soil, can be designed independently of the constraints existing foundation, and can take advantage of groundwater flow to help maintain a more constant temperature. This planning visit to the Swiss Federal Institute of Technology, Lausanne (EPFL) will explore opportunities to collaborate on two important research questions regarding these technologies. The first is the effect of the repeated heating and cooling cycles on soil properties. Depending on the type and state of a given soil, these cycles may strengthen or weaken the soil, and may cause expansion or contraction of the soil, affecting the foundation and substructures of the buildings that use these systems. The second question is the comparative efficiency and cost effectiveness of these energy geostructures. A planned outcome of the visit is competitive proposals on the US and Swiss sides for a collaborative numerical and experimental program to study these questions. Using an existing heat pile at the Swiss Federal Institute of Technology, Lausanne (EPFL), and heat pumps planned at University of Illinois at Chicago, we will monitor the performance and changes in soil properties over time. We will then develop models to capture the observed behavior. The broader impacts of the planning visit and follow-up research include: better understanding of the behavior of soil and changing conditions, improved computer models for this behavior, and tools to evaluate the efficiency and effects of different energy geostructures. Ultimately, this research will lead to more economical and more energy efficient ways to heat and cool buildings. In addition, the project will support a junior faculty member and provide an American undergraduate student with a first international research opportunity.