An energy model is a design tool...not a compliance tool!

Energy modeling, especially on a large, complex building, is a tedious and time-consuming process...but if you're designing a GCHP system and GHX, it's the most powerful tool in your toolbox. The building and building systems are something you can have some control over. There are a number of things you can do while the building is still in the early design stage by using an energy model, first to...

Building insulation values, roof construction, glazing, energy storage, design of the distribution system, ventilation system strategy (HRV, ERV, CO2 sensors) all have a major impact on both the building peak heating and cooling loads as well as the annual energy loads. They all can have a major impact on the size and cost of the GHX. Reducing the number of boreholes or the amount of trenching required can cover the cost of the energy saving features such as glass, lighting, insulation, lighting controls, etc.

More importantly, these are all tools that can balance the amount of energy you are trying to reject to the GHX with the amount of energy you are extracting from the GHX. Balancing the loads does three things:

• Reduces the amount of pipe needed in the ground - less drilling or excavation
• Reduces the spacing needed between the pipes - less land area needed
• Ensures the GHX temperature does not gradually increase or decrease over time

It makes the system less expensive to build and improves building and system efficiency...improving the owners return on their investment. If you are using an energy model only after the building has been built simply to comply with building code requirements or LEED you are not using one of the most powerful design tools you have available.