In this project, I worked with a team of three other Cal Poly mechanical engineer students and an architecture student to design a tiny home with an innovative passive heating and cooling system. The intent of the structure was to be cheap and easy to assemble in remote places for temporary or emergency purposes. We built and tested a 1:4 scale model of the full size tiny home to validate the systems.

The system uses water bladders on the roof of the structure covered by retractable insulation panels to control the direction of heat transfer either into or out of the structure. Water was chosen as the insulating medium because it has the highest specific heat capacity of any common material. The insulation panels are connected to a spool of rope on an axle which is driven by a hand crank chain system.

During a warm day, the insulation panels cover the water to provide maximum protection from the sun’s thermal radiation. At night, the panels are moved off of the water to allow the heat stored in the water to dissipate into the atmosphere. During a cold day, the water is left uncovered to absorb maximum thermal radiation from the sun. At night, the panels are moved onto the water, directing heat stored in the water into the home.

During both hot day and cold day tests, the interior temperature of the home did not drop below 58F or go above 73F, which is within the range of Merriam-Webster’s medical “room temperature” definition.