Geothermal and Aerothermal: Mature Alternatives to Meet ESG Goals

June 9, 2022

It is well known that Environmental, Social and Governance (ESG) issues have become more relevant and a decisive factor in the financial sector especially when looking for and choosing where to place its resources. As a result, this has caused an increased focus on searching for sustainable projects around the world.

As such, many clients have begun looking for resources that allow them to address global challenges, such as climate change, as they become aware of the need to comply with mounting concerns from investors and consumers, especially when it comes to ESG. For this reason, they are continually asking for alternatives that they could use to demonstrate the measurable results obtained, because of their efforts.

To address ESG, there is a universe of possibilities, however, one of the ideas that we typically evaluate is our clients’ operations and if there are more efficient ways to controlling (i) the ambient temperature within their facilities, whether it’s an office building or industrial buildings, as well as tracking (ii) the records of consumption for hot or cold water at their facilities.

It is well known that in the south of the United States and in much of Mexico consumers are going through a streak of droughts that has increased the price of natural gas because its role in generating electricity. Today, the people and companies are requiring more energy to cool their facilities, so it is important to think about alternative energy sources that are friendly to the environment and that allow us to reduce our carbon footprint, while trying to reduce your energy bill.

In that sense, there is a potential solution, but is not as widely adopted and one that we recommend and that is to evaluate the implementation of geothermal or aerothermal technology. It is a solution ripe for application despite the fact that Mexico is positioned as one of the countries in the world with the greatest generation capacity, it has not been fully exploited, mainly due to ignorance of the technology or its limited diffusion, has the ability to offer very interesting results for certain load profiles. I did not understand the words here.

Both geothermal and aerothermal energy provide forms of heating efficiently and therefore represent considerable savings on an energy bill. According to the U.S. Environmental Protection Agency, geothermal interchanged air conditioning is the best technique available for the generation of heating, cooling, and domestic hot water in all types of buildings (residential, commercial, and industrial). Both are mature technologies that are known and used with good results in countries such as Germany, Austria, Switzerland, Sweden, and France, where the use of this energy has been carried out for more than 40 years.

Geothermal energy, which offers the greatest potential, is the system that contributes the most thermal energy to heating in relation to its consumption. Some analysts say that for every kWh it consumes, it con-tributes five kWh of thermal energy to the installation. Those four renewable kWh are captured from the heat exchange contained in the depths of the earth; and that is where the value is, since it is an inexhaustible source and is available practically anywhere on the planet.

It can produce heat and cold simultaneously, which allows it to be used for different reasons, either cooling a building and or preheating water for some industrial processes, among others.

The heat pump is one of the main components of the system, but it requires consuming energy to operate, which can be reduced or eliminated if combined with an on-site photovoltaic generation system, which allows the system to be closed, making it one hundred percent self-sufficient and renewable.

The way in which the geothermal system operates is based on the geothermal heat exchanger, which is in the subsoil, either horizontally at a low depth, and or vertically at a greater depth, when is required at greater exchange heat capacity Not sure what we are saying here. The exchangers are pipes that are buried by drilling into the ground at a depth of between 80 and 140 meters. In the case of vertical ones, they are between 2 and 3m for horizontal ones, depending on the installed power and conductivity of the terrain. The pipe, or probe, as it is known in the medium, contains heat transfer liquid (like the antifreeze liquid we use in our vehicles), which when circulating in the system collects the temperature of the subsoil.

Typically, the soil is at a constant temperature of around 15°C at a depth of between 5 to 10 meters due to the thermal inertia of the soil, which stores the heat of the sun. From 10 meters deep, the temperature tends to increase around 3°C every 100 meters.

This piping system is connected to a heat pump. Geothermal exchangers capture energy from the subsurface at a relatively low temperature and by using a heat pump the temperature is increased to the required level. In summer, the process is reversed by injecting heat from cooling into the earth.

The geothermal pump causes the heat carrier liquid to reach the evaporator, where a refrigerant fluid is found at a temperature of between -5 and 0°C. That’s where the magic occurs: as the heat carrier liquid in the buried pipes gets hotter than the cooling fluid, a heat exchange occurs, causing the refrigerant fluid to heat up and evaporate. The two liquids never touch each other, but exchange heat due to the proximity of the pipes.

The refrigerant fluid, now in a gaseous state because it received the heat (energy) from the heat carrier, passes through a compressor that, driven by electrical energy, increases the pressure of the refrigerant steam, thus increasing its temperature to between 60 – 90ºC. At that point, the refrigerant fluid is already in a gaseous state, so it enters the condenser, through which the heating system pipe (HVAC) also passes. The vaporized refrigerant pipe gives heat to the water, causing the water to heat up and providing radiation heating to the building or to use it directly to some industrial process that requires hot water. The cycle starts again and is repeated when the refrigerant fluid, once it has provided its contained heat as energy (not sure what we are saying), returns to its liquid state and passes through an expansion valve to reduce its pressure and finishes lowering its temperature to reach the evaporator again.

If what you are looking for is cold, then the system is worked in the opposite direction. What does this mean? Answer: It means that the heat exchange system works as an inverter (capturing the heat from the refrigerant fluid).

Aerothermy is a similar concept and is based on a technology that extracts energy contained in air from the atmosphere, which contains the energy emit-ted by the sun, although the costs of current technology are not yet very competitive vis-a-vis conventional heating, this will be reversed soon.

Many companies, mainly European, have successfully installed these systems in the recent past, but mainly those in food, textiles and mining stand out, in which their processes require cooling or heating of process fluids and production of domestic hot water.

The implementation of these technologies is not generic or cheap and the situation is different, so it is advisable to make a business case and an in-depth analysis of the needs and limitations of heat resources that the site presents with the intention of evaluating the economic and financial viability of this solution in your facilities.

At Acclaim Energy, together with our partner Cornerstone, we are ready to help you develop your strategy to implement your ESG goals in a professional manner, we invite you to download and read our whitepaper “What is ESG? and your “Tendiente Crecimiento” on our page.