Design, Simulation and Preliminary Results of an All Electric Net-Zero Energy Solar Home

This paper describes the mechanical systems, the DC-coupled electrical system, the simulation approach and the preliminary results of the University of Illinois entry in the 2007 Department of Energy Solar Decathlon competition. The competition showcased twenty net-zero energy solar powered houses. The University of Illinois entry was the only one that featured an all-electric design. No solar thermal collectors were used; space and water heating was accomplished primarily through heat pumps. Each of three house modules is sensibly conditioned with autonomous, custom mini-split heat pumps using all radiant and natural convection heat exchange for the interior side. Simulation methods are described and assumptions of wall and window properties, mechanical system performance and electrical system performance are disclosed. Details are provided on the theoretical analysis of internal heat transfer and the basic design of the custom mechanical system. The electrical system topology and equipment choices are presented and initial performance results are shown. Additionally, preliminary analysis is carried out on the data taken during the Solar Decathlon competition and on the observations of post-competition winter performance. The success in being awarded comfort conditioning points during the competition is discussed along with drawbacks not represented in the competition results.