Loop Fields

It is extremely important to understand that a closed loop heat exchanger must be designed to closely match the heating, cooling and hot water needs of a residence or business and it’s occupants. Without that specific data nothing is true, it’s only a guess. Sometimes a good guess but more often than not, it’s only a guess. Rules of thumb have been adopted by many in different industries and trades but this task must be left to those who have a proven track record and performance history.


Some Rules To Live By

Never interview a well driller, driller or so called geothermal earth loop installer first. If they start to tell you that your home or business needs a certain earth loop length and that they have done similar homes and jobs before, then politely show them the door. If you are told something like “this is a four ton job, so that will be 4 times 150 feet per ton”, same thing…. the door. While their services are important to the operation of a geothermal heat pump, unless they have actually engineered and installed an earth loop, connected it to equipment and guaranteed its performance and comfort they are not the starting point by any means to designing a heating, cooling and hot water system.  If you take their advice first you are most definately putting the “cart before the horse”.

There are lots of applications for geothermal systems and earth loop personel are not usually qualified to tell any inquiring party that their building is not applicable to a geothermal or any other heating, cooling and hot water system. At a minimum they should be qualified to identify if the geology of the property is suitable.

FACT…most heating and cooling systems are oversized. Equipment is most often installed using minimal, if any, engineering data. The equipment can not operate as it was designed by research and design engineers because it is installed in an unengineered environment. Consumers suffer from discomfort, premature equipment failure and high utility costs as a net result. Does it not make sense to fix this problem with your next investment ? Why install a new HVAC system based on the improper credentials of the existing HVAC system ? Find a contractor with a thorough proven track record.

If a “certified” geothermal person tells you they are certified, ask them what’s their definition of certified. Who certified them and when ? If they have successfully passed an International Ground Source Heat Pump accredited installer exam then that’s a start. After that, ask how many successfull geothermal systems have they installed. Then ask how many unsuccessfull installations they have installed too and what they did to correct their problem.

A new geothermal system or any new heating/cooling “box” for that matter will not fix an installed air distribution system that is improperly designed, if it is designed at all. If you have uncomfortable areas they will remain uncomfortable. Just like an auto mechanic can install a new engine, but the transmission has a problem too and the mechanic did not address that problem too.

Horizontal Loops

Horizontal loops are often considered when adequate land surface is available. Pipes are placed in trenches using different configurations calculated specifically from data collected during an energy analysis calculation.

Vertical Loops

Vertical loops are the ideal choice when available land surface is limited. Drilling equipment is used to bore small-diameter holes from 75 to 300 feet deep.

Pond (lake)

Pond (lake) loops are very economical to install when a body of water is available, because excavation costs are virtually eliminated. Coils of pipe are simply placed on the bottom of the pond or lake.

Open Loop

Open loop systems utilize ground water as a direct energy source. In ideal conditions, an open loop application can be the most economical type of geothermal system.

Closed Loop

Closed loop systems circulate a water-based solution through a “loop” of small diameter, underground pipes. In cold weather this solution absorbs heat from the earth and carries it to the geothermal unit. The geothermal system amplifies the heat and delivers it indoors. In warm weather the process is reversed, excess heat is carried from indoors and into the earth. You keep refreshingly cool during the hottest summer.

Boiler / Tower Systems

Boiler/Tower Systems For efficiency upgrades where large geothermal systems are not viable, existing boiler/tower jobs are frequently retrofitted. Hybrid systems incorporate both geothermal loop coupled with down-sized conventional heat rejection or addition equipment (boiler or tower).