Buildings currently constitute about 25% of greenhouse gasses that deplete the ozone layer which is a direct result of HVAC systems that use fossil fuel and refrigerants. THEC is a sustainable and environment friendly product with zero emissions. It is a GCHE (Ground-Coupled Heat Exchange) system and a portable technological advancement to the current similar systems which are bulky and require large parcel of land for installation. This portability is achieved by the introduction of a thermal storage chamber (12ft x 7ft x 7 ft) which can reduce required lots size by up to 92%, thereby enabling the installation of an efficient GCHE system in a standard townhouse yard. It can be installed as a retrofit in existing buildings or in new construction. 

It functions on the principle that the ground temperature at 6ft below grade is constant all year round (in Canada it is 10 C to 16 C). It is so because the earth is a storage device for the sun’s energy which is produced in excess of the amount we need. The heat exchange chamber is buried not less than 5ft below grade and connected to a fresh air inlet pipe and an air outlet pipe which is then connected to the regular furnace blower in the house to supply hot air. The furnace blower is activated by a regular house thermostat and that triggers the movement of air into the house through the chamber. An air filter can also be installed at the blower. A shutter is installed at the outside fresh air inlet so that this inlet can be occasionally closed during severe winter and the system operated as a closed loop.The pipes can also be sloped to collect condensation that could lead to health problems.

There is a heat exchange by conduction and convection between the incoming air and the pipes in the chamber and the temperature of air that is sucked into the house is stabilized as stated. The thermal storage medium in the box is ‘recharged’ by the 10 feet of clay soil installed around the box in order to prevent positive or negative heat gain by the medium thereby maintaining constant indoor temperature.

Your task is to design and build a small scale prototype for this system as a proof of concept. It should be a maximum of 4ft x 2.5ft x 2.5ft in size and should include some or all of the following elements, depending on what your group decides to focus on:

Here is a preliminary concept of THEC, however feel free to adapt as you see fit.