Introduction to DHE

Drilled Hydrothermal Energy (DHE) introduces a sustainable approach in the field of comfort and process cooling that can be adopted by certain coastal communities to both decrease CO2 emissions as well as increase CO2 absorption by the oceans. This approach targets coastal communities that have deep cold water (4oC) within the reach of horizontal directional drilling, a drilling technique that is commonly used in the oil and construction industry. When brought onshore, the cold water is utilized for hydrothermal cooling in lieu of mechanical cooling.

Projects harvesting energy from the ocean by laying down pipes dates back to 1929 in Cuba. Pioneering efforts have been made to use this deep cold ocean and lake water for space cooling since the 1980’s at Hawaii’s NELHA. There are four major projects around the world that use natural cold water for space cooling. These projects have exhibited remarkable savings over mechanical cooling of up to 90% and yet other coastal communities with deep cold water close to shore have proposed similar Seawater Air Conditioning (SWAC) projects but have not been able to gain traction. These projects used a process of controlled submergence of pipes with concrete collars into the body of water. This process is not without risk in installation and many potential sites have sensitive seafloor environments which must be crossed to access the cold water. Such projects may either be too costly or will not meet the rigor of an environmental assessment.

DHE propses an innovation to overcome past deficiencies by using a mature technique used in petroleum extraction known as Extended Reach Drilling (ERD) or Horizontal Directional Drilling (HDD). This technique enables directional drilling under the surface to access deep cold water with a horizontal displacement of up to eleven kilometers from shore. In addition to cooling, directional drilling to a warm water source of at least 36°F (20°C) temperature differential has the potential of generating electric power by using heat exchangers and Organic Rankine cycle turbines. Preliminary designs estimate that approximately 10 megawatts of power can be obtained from heat exchangers and a turbine generator designed to the envelope of two or three ISO 40 foot containers per module. Four times more power is theoretically possible by integrating solar energy provided space is available. This power may be used for many purposes including power generation for island communities without burning fuel, water desalination, hydrogen or ammonia fuel production and oxygen waste water treatment.

As Albert Einstein once suggested “We can’t solve problems by using the same kind of thinking we used when we created them.” The “thinking” presented herein suggests addressing the excess amount of CO2 that is being emitted into our atmosphere by not only reducing the rate at which we currently emit more CO2 but by also absorbing the CO2 out of the atmosphere and into our oceans where it can be used to improve our environment. Government, NGO, commercial, academic and research institutions are invited to study and model this innovation in areas within 11 kilometers of 4°C water. HVAC professionals are well advised to consult with oceanographers, geologists, and directional drilling professionals to assess the natural cooling opportunity in their local community.