Sizing Your Geothermal Heat Pump System
In
order for your geothermal heat pump (GHP) to function correctly, it is
important that it is properly sized (most systems are sized to meet all of
your space heating and cooling needs). As with all heating and cooling
equipment, oversized GHPs are more expensive and will result in decreased
energy efficiency, poor humidity control, and shorter product life due to
excessive on-off cycling. Undersized heat pumps will rely too heavily on a
supplemental backup system, which can increase operating cost.
Your system supplier or installer should perform a thorough analysis of your space heating and cooling, and hot water, loads using established techniques (such as the Air Conditioning Contractors of America's Manual J method) to help guide heat pump selection.
In addition, your supplier or installer should be familiar with the geological and hydrological properties of your site to ensure proper ground loop design and sizing.
To get a rough approximation of the size system your home or business would require, DOE's Federal Energy Management Program estimates that you will need a ton of capacity for every 550 square feet in heating-dominated climates, and a ton for every 450 square feet in cooling-dominated climates. (One ton of capacity is equal to the heat required to melt 2,000 pounds of ice in 24 hours, or 12,000 Btu per hour.)