CLOSED LOOP AIR GROUND HEAT EXCHANGER
designed by Daniel Barbu-Mocanescu
The geothermal energy (or earth's energy) is one of the renewable sources of energy available in abundance and without interruption, regardless of season or region. It can be easily used for both industrial and residential applications. The most common solution used in buildings is the geothermal heat pump (or so-called ground to water heat pumps) for heating/cooling the building.
Another simple method of harnessing the thermal potential of the earth is the ground-to-air heat exchanger, or generically called "Canadian Well". It consists of a pipe of a certain length (usually 40-50m) buried in the ground at a certain depth (usually 1.5-3m) and a simple fan that flows the fresh air through the pipe. The fresh air is pre-heated in winter and pre-cooled in summer by the shallow geothermal energy of the soil, thus gaining a few degrees (eg from -5 °C, the outside air can be warmed up to 4-5 °C). However, the system must be equipped with a condensate drainage mechanism and the pipe must be a special one, treated with silver ions on the inside to prevent the formation of bacteria, thus increasing its cost. Overall, the system is simple and efficient and worth the investment.
However, the system can be improved and taken to the next level. Our colleague Arch. Daniel Barbu-Mocănescu developed CLAGHE (Closed Loop Air Ground Heat Exchanger), in order to ensure a constant supply of fresh climatized air, at optimal comfort parameters, both in summer and in winter, without additional sources of cooling or heating. CLAGHE consists of a closed-loop geothermal exchanger buried in the ground at a certain depth, an air-to-air heat exchanger, and a heat recovery ventilation system.
The depth and the length are calculated depending on the location and type of soil and it has the role of harnessing the thermal energy of the soil, regardless of the season. The outdoor fresh air is first pre-heated/cooled by the geothermal exchanger, and then is being warmed up/cooled down by exchanging heat in the heat recovery unit with the polluted air evacuated from inside, without being mixed.
The great benefit of CLAGHE is that it climatized the fresh air to reach the optimal comfort parameters, both in summer (24-26 °C) and in winter (20-23 °C), at a minimum energy consumption, as compared to 2 light bulbs. Another benefit is that it prevents the appearance of bacteria or radon in the air circulated in the system, without the need for special pipes or other expensive materials. The CLAGHE system is easy to install, preferably before the house is assembled and the investment cost pays off in less than 5 years. Then you can cool down and heat up your house almost free of charge, just with the earth's renewable energy.