Working With It: Sizing
Requirements
The requirements for sizing of a heat pump system are:
- The building's heating and cooling loads, and the domestic hot water heating requirements, must be provided by the heat pump system.
- An estimate must be made of the ground heat exchanger loads given the heat pump operating hours.
The steps to follow in sizing a geothermal system are:
1. Calculate the building's heating and cooling design loads using one of many methods, including:
- Hand calculations based on ASHRAE recommendations;
- Air Conditioning Contractors of America Manual J for single family detached homes; or
- Manufacturer or other accepted computer software programs.
2. Select a properly-sized heat pump to serve these loads.
3. Select the type of indoor distribution system. An air system is typical for single family residential and some commercial and institutional applications. A water-to-air system is often considered for larger multi-zone commercial buildings.
4. Size the indoor distribution system. There are a number of manuals and some software programs that can assist the distribution system designer.
5. Select the proper air supply and return diffusers, registers and grilles.
6. Estimate the building's energy requirements given:
- The heating and cooling loads;
- The type and size of heat pump equipment selected; and
- The thermal characteristics of climate and soil.
7. Estimate the ground heat exchanger loads, considering the annual load and the design month's load.
Rule
Learn more about:
How It Works: Geothermal Concepts
Resources: Incentives & Financing
rule
Brochures and fact sheets
GeoThermal: Bringing Comfort to Your World
By Alliant Energy
[PDF format – 7 pages, 174kb]
