Loop Pumps

 

The circulating pump in a system should provide a flow of fluid through the ground source loop adequate enough to maintain good heat transfer during both cooling and heating operation modes.

The circulating pump must have sufficient power to overcome the resistance encountered while flowing through the:

  1. Ground heat exchanger and headers
  2. Heat pump water to refrigerant heat exchanger
  3. Equipment room piping - including all fittings and hoses.

For Residential and small Commercial Installations, many heat pump manufactures offer standardized pump modules that include the circulator and the necessary valves for system charging, maintenance and operation. Some include a reservoir for air trapping. Others include a self-flushing feature and an air purging system.

For commercial installation, the circulating pump must be selected to meet the requirements determined by the designer.

A flow rate of 2 to 3 gallons per minute per nominal ton of cooling capacity and water pressure drops in the 25 to 30 foot range are typical. Note, the pressure drop with antifreeze solutions runs 25 to 36 percent more than with water.