This is an alternative that can be used in buildings with high requirements and that also allows to recover large amounts of energy, cooling and heating the conditioned environments without increasing costs.
by Alfredo Sotolongo*
I recently heard something that caught my attention: "The ecological impact of applying geothermal systems in the United States is equivalent to taking 1.1 million cars off the road or planting 300 million trees."
How accurate is this? It is irrelevant. What is a reality is the fact that geothermal systems are ecologically beneficial for cooling, heating and dehumidifying conditioned environments, recovering energy that other systems, more commonly used, waste.
It is important to indicate that underground, the temperature remains relatively constant in relation to the temperature at the surface and that in addition, the earth has a great capacity to store energy. This makes it possible to use the underground levels to discharge or absorb heat through a distribution of vertically or horizontally oriented water pipes. By changing the weather conditions on the surface and reflecting this change in the conditioned area, the system changes the cooling cycle and recovers the energy that had been discharged to these underground levels.
For example, air- or water-cooled systems that discharge energy to the outside environment waste that energy because it cannot be stored and is lost. However, in geothermal systems the energy discharged to underground levels is stored and when the cooling cycle changes, it is recovered for use in the new cycle.
In our South American countries with more extreme weather conditions in both summer and winter, it is very possible that there is such a necessary thermal balance so as not to need to complement the system with cooling towers or boilers. During the summer energy is absorbed from the conditioned area and stored at underground levels to be recovered during the winter and provide the necessary heating.
I was able to verify this during a visit to the AAON air conditioning equipment factory in Tulsa, Oklahoma, where the weather conditions are quite extreme, hot summer and very cold winter. They conditioned part of the production line using a geothermal system with all the necessary sensors and meters to demonstrate the complete operation of the system and its benefits.
Self-contained, water-cooled units that operate as heat pumps can operate in cooling or heating when the water temperature is kept within a fairly constant range. Also, when the conditions of the conditioned areas require that they be some in cooling and others in heating, the heat that is discharged product of the units in the cooling cycle is used by the units that are in the heating cycle.
In our tropical countries or where winter conditions are more moderate, it is necessary to help the system with a cooling tower and/or boiler. In both cases these devices are much smaller than when the geothermal system is not used.
As I always tell you, it is extremely important to analyze the initial investment including the analysis of the subsoil, the cost of supplying and installing the underground pipes, and the backup equipment including the cost of operating them, such as the cooling tower and / or the boiler. This should be compared to the projected reduction in electricity consumption.
I am sure that in most cases the investment is recovered in a reasonable time. Especially in those of our countries where the cost of electricity represents a high percentage of the cost of operation. This also entails an added value, the positive ecological impact.
If you need more information on any of the topics covered in this column, please contact me at the email [email protected]
* 
President of Protec, Inc., he is certified as a professional engineer in Puerto Rico and in the state of Florida; he has more than 40 years of experience in the application and sale of systems and equipment for energy conservation. He is a member of ASME (American Society of Mechanical Engineers), AEE (Association of Energy Engineers), ASHRAE and was president of the Miami chapter of that association.
