Understanding Energy Loops
Energy loops come in all shapes and sizes.
Including high density horizontal, slinky loop , vertical loop and pond loop systems. But the goal is always the same: To link the geothermal heat pump to the energy stored in the earth.
Here is a simple high density earth loop. The tubes go out and return in the same trench which is then covered with earth. On this application, there is a soaker line installed with which insures the loop field stays damp for better heat transfer. Of course the length and number of tubes varies with the size of the heat pump, building heat loss and local soil conditions.
In places where there is not enough room to trench, "slinkies" are used.
A slinky is a length of tubing which is coiled and placed in a pit and then covered with earth. Again, the amount of tubing is adjusted to the heat pump and the depth of the pit is calculated for the area climate.
Below are examples of residential, farming and commercial geothermal installations.
Below is the Bullerman home located in Nobles County, Minnesota. This beautiful 2-story house has 2600 sq ft each on the main floor, second floor and basement level with a 1426 sq ft garage. Busse Plumbing and Heating of Luverne, Minnesota (Jim Remme, owner) is the mechanical contractor.
This home is heated and cooled with a staged 12 ton hydronic geothermal system with a variable speed fan coil and a water coil over a furnace which qualifies them for the dual fuel rate. The two 6 ton heat pumps feed an 80 gallon buffer tank which, in turn, serves the fan coils, radiant floor heat for the basement, garage and joist pocket heating for the main floor. The loop field is (12) 800' horizontal loops manifolded inside. This system was planned and installed to provide all the comfort and economy that geothermal systems are known for.
Estimated cost of heating and cooling this 2600 sq ft 2 story home and 4 car garage is $1145 per year with the geothermal system at $.045 kW dual fuel rate as opposed to the $5122 per year projected cost of operation using LP at $1.60/gallon for a projected annual savings of nearly $4000 per year!
Big jobs require big earth loops. Pictured on the left is an earth loop for a large commercial job. The crawlers are actually in the pit covering the earth loops.
Another variation on the earth loop is the vertical loop, shown on the right. A drilling rig makes a series of bores in which loops are placed vertically, connected together and piped to the heat pump. This approach is commonly used when there is not enough space to put in a horizontal or slinky type loop field.
To the left is an example of a pond loop. These loops are referred to as "slinkies" and are floated out into a pond and sunk. Solution is then pumped through the loop field, energy is absorbed into the liquid, and supplied to the heat pump. Pond loops are very efficient and produce a more constant temperature as the water circulating around the loop brings the energy to the loop.
So how do you put in a pond loop without digging up the yard?
This contractor used a directional boring rig to bore under the yard and into the pond. He then constructed the pond loop mat, floated it into position and pulled all the loop tails through the bored hole and back to the house. When the loop field was purged of air and filled, the weighted loop field sunk and the pond loop was complete. One option would be to manifold all the loops in the pond and run just 2 larger pipes back to the house.
THIS SOUNDS COMPLICATED!
Be assured, your geothermal contractor will work with Terra-Therm to make sure that your earth loop is designed with all these factors considered. This insures that your heat pump will deliver the comfort and economy you expect from your investment. We have over 20 years of successful experience in working with our contractors to bring the benefits of geothermal energy to their customers.