What are the differences between open loop and closed loop systems?
An open loop, also known as a “pump and dump,” needs an adequate water source. It uses groundwater from a well as a direct energy source that is then “dumped” into a nearby stream, lake or floodplain. Mineral deposits and water quality may cause maintenance issues. Cost is $200-$400 a ton. A closed loop circulates a pressurized mix of water and methanol through the loop field. A four-ton system needs about 120 gallons of the mix. Horizontal closed loops are about $1,100 a ton; vertical closed loops are about $2,000 a ton; a pond plate, about $1100 per ton; and a closed pond loop, about $500 per ton.
