Case Study Home # 4
Basement Energy Prototype

Evaporative Cooler / Geo-Exchange / Basement Energy

Edgewater, Maryland

Our renovation project is a two story 1500 s.f. home, with a 500 s.f. basement. The home has been gutted to the framing, and insulated with spray foam, and sealed as an air tight envelope, therefore requiring “Continuous Whole Building Ventilation”, for healthy indoor air quality.

The beauty of our energy exchange system is that it harnesses the “Geo Thermal Energy” of the earth, and natural cooling effect of evaporating moisture. We began with the need to convert a damp basement into a dry mold free space. The damp, musty, cool, un-waterproofed basement walls inspired our concept of harnessing the Earth’s natural & thermal energy to create Geo-Exchange cooling and heating. This transfer of geo-exchange energy is accomplished by surrounding a basement w/ a ventilated envelope, by means of an Energy Recovery Ventilator (ERV).

During the cooling season, the ERV extracts the moisture from the fresh incoming air and delivers dehumidified fresh air into the building envelope. Within the basement, we created a sealed air tight living envelope surrounded by an air cavity adjacent to the existing old subterranean walls. These leaky walls also “wick” moisture, as well as sweat condensation during the hot / humid summers, thereby creating a natural environment for an evaporative chiller. Our approach is to encourage the presence water, contrary to traditional thinking, and our system harnesses the evaporative cooling effect resulting from ventilating a cavity with “dry stale air”.  The aforementioned, will result in dramatic cooling at minimal energy use of approximately +/- 150/watts of electricity / hour.

When in the heating season, we incorporate an additional HRV unit ventilating the basement cavity producing “Geo” pre-conditioned fresh air entering the main house ERV.  This will boost the temperature of the cold exterior air with the Geo-Exchange temperature from the basement envelope air cavity; therefore the earth’s temperature will assist the home’s winter heating needs.

Due to the phenomenon of “Thermal Lag”, the basement structure now has become a thermal heat sink and storage unit, assisting the performance of the building’s heating and cooling system. The basement structure and adjacent earth, during the summer, will be cooler than normal due to the winter’s heat extraction cycle, and it will be warmer than normal at the beginning of winter, due to the dumping of heat during the summer. This results in thermal energy lag effect in the foundation and soil, which assists the home’s heating and cooling.

Our goal is to make our heating and cooling system a “passive / hybrid” / geo-exchange system, eligible for geo-thermal federal tax credit, by illustrating a new and efficient system of energy for our homes.

Geo-Cavity Sucess!
Patented System 

Winter Cycle
Summer Cycle

James Wright, Walter Bennett, and Klas Haglid 2011