Overview Building Features Grade JK-6 Grade 7-12

Earth Tubes

Real Time Data
a Supply Fan VFD % Speed: %
b Outdoor Air Damper % Open: %
c Intake Air Temp °C: °C

Earth Tubes also may be referred to as air-ground heat exchanger, earth warming/cooling tubes, earth channels, earth air tunnels, underground air pipes.

Earth Tube Design Layout Plan

An earth tube is a heat exchanger arrangement in which a pipe or tube is buried to facilitate the transfer of geothermal energy with air. This system utilises the near constant ground temperature to either extract or reject heat energy to or from the incoming air stream with the ground. Outside ambient air passing through the earth tubes is either heated or cooled before entering the building air system. In the summer, the earth is cooler than the outside air temperature and the air will be cooled as it passes through the tubes; the opposite occurs in the winter. Piping materials used may be plastic, metal or concrete; each material type has its pros and cons. This is considered a "passive" renewable energy system in that external mechanical energy is not used to generate the heat transfer effect, only a fan is used to move the air through the pipe. Generally, the temperature change of this type of system is not enough to fully condition the passing air but is a simple, energy efficient means of pre-heating or pre-cooling it.

How it is used in the school:

Air Inlet Tower Detail Condensate Collection Shaft Detail

Earth TubesAn earth tube system is installed in the building and coupled with the 1st and 2nd floor corridor ventilation system. The earth tube system is mainly comprised of a white polyvinyl chloride (PVC) piping material that is impregnated with an anti-microbial coating on the interior surface. Outside ventilation air is drawn in through an air inlet tower located near the playing fields at the back of the school, and then down into the ground to a depth of 5ft before travelling an additional 150 ft horizontally and entering the building below the gym foundation wall. Once inside the building, the earth tube system continues beneath the gym floor to the exercise room and then travels vertically up to the 2nd floor mechanical room where it is connected to air handing unit (AHU) #4. A portion of the earth tube system is displayed in the first floor exercise room and appears as six (6) vertical 8" diameter white PVC pipes. The pre-conditioned ventilation air that is drawn into the building year round through the earth tube system reduces the amount of conditioning energy required by AHU#4. 

Greater Essex County District School Board