Anyone can use geothermal energy in achieving thermal comfort by passing atmospheric air inside any buried heat exchanger and forcing this cooled air to the space.

Dear Dr. Gamal B. Abdelaziz What is the suitable depth and what are the materials that should be used?

Thanks

Thanks Dr. Harish Puppala

I have sent you a request for your paper.

Regards

Ground source heat pumps, also known as geothermal heat pumps, are one of the most accessible ways an individual can utilize geothermal energy. These systems do not actually use geothermal energy directly, but rather use the earth as a heat sink to create a much more energy efficient heating and cooling system. I have attached the text from an article published in Ecogeneration magazine in 2011 that provides some more detail on how they work.

Dear Mark Ballesteros

Actually I'm thinking of making such a system in my farm land which is located near by a water streamlet. What kind of pipes should I use? I mean what is the pipe material should I use?

Another question, should I dig in the ground and put sand around the pipe instead of clay to make the thermal conductivity greater?

The most common options are PVC plastic and copper. Copper has a higher thermal conductivity so it will transfer the heat more efficiently, however it is much more expensive and much more susceptible to corossion so PVC is probably a better option.

The simplest technique to use geothermal energy is to extract heat from earth in winter or by a heat exchanger or reject heat from your space to earth in summer.

I have an experimental model in my home.

Thaer Roomi thank you for your comment. the suitable depth is about 2-3 m

Dear Prof. Thaer Roomi regarding to your question: what are the materials that should be used?

The suitable material is pottery

I have an earth test rig in my house.

Mark Ballesteros is generally right except I have never seen PVC pipe used for ground-source heat pumps and it seems very risky to me. Many years ago it was polybutylene. Now, polyethylene and cross-linked PE are most common. see igshpa.org/standards/ (installation standard). GSHPs (sometimes called geothermal) are as Mark says not "geothermal" energy but a ground heat exchanger with an electric heat pump. Loop temperatures in winter are actually much colder than the ambient underground (and summer is warmer) because the extracted heat cools the earth near the heat exchanger (heats in summer). They can be incrementally more efficient than a cold climate variable-speed air source heat pump, because the underground temperatures are always more moderate than outdoor extremes, but cost a LOT more to install due to the loop requirement and especially difficult in dense urban environments where air source is the best option. ISO 13256 ratings are a bit misleading (optimistic) because they don't include fluid pumping energy or indoor fan energy beyond 0 static pressure, that systems require to operate. A design has to account carefully for pumping requirements, which if oversized can really kill the efficiency even relative to air source systems. Loop design is also critical, can be vertical or horizontal but if it's too short or badly designed (or multiple loops aren't connected properly) it can ruin the performance.

See also www.nyserda.ny.gov/-/media/Files/EERP/Residential/Geothermal/geothermal-manual.pdf (recent field study by a colleague; high efficiencies from top-end equipment with generally good loop design). In 1996-2000 I measured about 200 GSHP installations, many of them used domestic water wells and had oversized pumps and poor efficiency (one had a COP as low as 1.2). The industry has gotten much better in the northeast US, but you still have to be careful and do a good design. Right now there is growing interest in community-shared loops (on a scale of ~10 homes in dense single-family neighborhoods) with utility or public investment in the loops as a service and individual heat pumps in homes. All are important steps to decarbonization.

Mark Ballesteros Copper and pvc are not good choice. pottery is more suitable

It is a suitable choice for cooling in hot areas and heating in cold areas. And better use cheap plastic tubes.

with success

The question really wasn't specific as to what they meant. Passive cooling and heating with earth tubes only delivers a modest tempering effect, heating or cooling. It's cheap to install and uses very little energy (fan only) or none (but the stack effect can only move intake air through the ground into a dwelling in cold weather. When it's hotter outside than in the house/tube matrix the stack effect lets cooler indoor air dribble out through the tubes and they won't cool the structure at all). And you have to be careful about underground moisture and condensation causing air quality issues. If you want to be able to condition a space to a reasonable temperature you would need a heat pump. Obviously that costs more to install and requires an electricity source to operate.

The differences between these concepts underlies the very different answers that have been posted. Neither of these are "geothermal" (deep-earth heat) energy; they basically take advantage of the insulation and thermal mass of the top layer of a meter or two of soil.

Dear Bruce Harley

Thank you for your detailed answers.

At the end of the above discussions, do you think the design to be made is impractical and does not make an important difference?

Thank you Radwan Almasri for your answer

Dear Gamal B. Abdelaziz

I have some questions:

1. Do you have any details (or pictures) of pottery pipes?

2. What is the air temperature difference between the output air and the ambient air?

Regards

Thanks for your reaction dear Thaer Roomi,

Soil and a domestic water tank were used as a sink to release the energy of the refrigerator condenser using PVC pipes, and energy savings of about 30% were obtained. I did not use it to cool the air in the soil.

regards

Working beneath earth surface is an emerging idea as scientist have worked above earth surface to get energy from renewable sources.Geothermal is more efficient firstly due to earth undistributed temperature(EUT) as we move at depth of 2 meter if soil have nearly the same properties and secondly in term of its ease to install.It can be helpful as alternative of electricity because a large portion of electricity in many countries is produced using natural gas which creates CO2 which increases earth temperature and results are infront of us in the form of climate change.The question is should we only rely on just sun & wind which don't have same magnitude not only in different places but it varies at a single place throughall.Geothermal is not only cheap but also safe for environment.