Bury the heat

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Advantages & Disadvantages 

Five years ago, geothermal cooling systems weren’t available in Cayman but a demand for more energy-efficient appliances, lower utility bills and a lighter carbon footprint changed this.

Geothermal cooling systems offer an effective alternative to traditional air conditioning systems as they use less energy, making them greener and, ultimately, more cost-effective for consumers.

How it works

Cooling systems – whether refrigerators, air conditioning units or geothermal cooling systems – all work by removing heat. While it may appear that they are producing cold, the opposite is actually true: the heat is continually taken out of the environment, and transferred elsewhere.

And therein lies the problem with air conditioning: the traditional AC unit is taking heat from indoors and trying to dump it outside, where the air is even hotter.

It’s what Steve Smith, chief executive officer of Enertech Global, leading geothermal system manufacturers in the United States, calls an “uphill job”.

Geothermal cooling systems on the other hand, take that heat and transfers it underground, where it is already cool.

The heat that is removed from the air is turned into water, which runs through a series of pipes. Because water is an excellent conductor of heat, it is easy to transfer the heat to water. 

The heat in this water needs to be transferred somewhere, however, before cycling back through the building to pick up more heat, and so it is sent underground, where the temperature remains at a constant 78 degrees Fahrenheit.

A series of bore holes are drilled in the ground and coils of these pipes are placed in the holes. The ground in Cayman is saturated with water, making it easy to transfer the heat in the pipes to the heat in the surrounding ground water. 

“There is so much ability to transfer heat into the water in the ground, even if everybody installed geothermal cooling, it wouldn’t affect the temperature of the water in the ground,” says Steve. “It’s not magic. We’re just able to take heat and put it in a milder place. We’re not using the water to cool the house but to unload the heat.”

Is it a green technology?

In as much as it is an energy-efficient means of cooling interiors, and therefore burns less fossil fuels, geothermal systems are eco-friendly.

If combined with solar power, however, the green ratings rise considerably. It’s a misconception that the two are not compatible, says John, and in fact they go well together because geothermal systems work at such a steady rate.

Geothermal cooling uses the ground we walk on to cool interiors efficiently.

Cypress Pointe North, which recently broke ground in Grand Cayman, is one development that will be marrying solar power and geothermal cooling. When complete, it will be one of the most energy-efficient residential projects in the Caribbean. 



Geothermal closed loop process at Cypress Pointe North