Energy modeling is a design tool...not a compliance tool

Energy modeling is usually considered time consuming and it's tedious. One of the primary reasons it's done at all in many architectural and mechanical engineering offices is simply to comply with LEED, the building code or various incentives. All too often the person tasked with developing the energy model is the least junior technician or engineer in training in the office...the person with the least experience about buildings and systems, and how they can impact the energy loads. Energy modeling, when used as the design tool...

it was meant to be, is the most powerful design tool a geothermal heat pump system designer has at his or her disposal...bar none. The size and cost of a GHX is based on five things:

• Peak heating and cooling loads to the GHX (kBtu/hr or kW)
• Annual energy loads to and from the GHX (kBtu or kWh)
• Balance of energy to and from the GHX on an annual basis
• Land area available to build the GHX
• Geology, or thermal characteristics of the site

A designer can do nothing to change the thermal characteristics of the soil and rock...it is what it is. Sometimes, the designer can influence the land area available to build the GHX, but usually that is predetermined. The only thing the designer can really have much influence on is the building heating and cooling loads themselves. By working with the owner, architect and the rest of the design team, the GHX designer can use an energy model to show the impact of the building construction, glass specifications, ventilation strategy, waste heat recovery, simultaneous heating and cooling opportunities, design of the distribution system, lighting, thermal energy storage, hot water production, etc. 

As a GHX designer, it's possible to play the building like a piano...you can fine tune the building loads by working with the design team to optimize the building to reduce the size and cost of the GHX. You can only do this by understanding the impact of the building and system design using a detailed energy model and, in turn, seeing the impact of the design on the GHX. 

An optimized design can cycle through as many as 12 or 15 iterations of the energy model to determine the impact of changes to the design. This cannot be done once the design of the building is finalized...it has to be done during the design process, and can only be done the person designing the GHX. It's very possible to reduce the size and cost of the GHX by as much as 40% to 60% using an energy model as a design tool rather than a compliance tool.