How Should You Use an Energy Model?
August 17, 2011 - Contact FacilitiesNet Editorial Staff »
Today's tip is about how to develop an energy model to be a useful predictor of how the building will use energy.
A prerequisite for LEED for New Construction certification, energy models amalgamate information about building systems to simulate approximately how much energy the building will use after it is built. Experts suggest that the energy model should be as important to the planning and programming of the building as the architectural drawings themselves.
One of the most important things to keep in mind regarding energy models is that they should be used not to predict exactly how much energy a building will use, but more to evaluate building choices and compare and contrast different strategies.
In regards to that idea of comparison instead of prediction, keep in mind these three points for how an energy model can be used to identify synergies in building systems and keep energy costs down.
1) Reduce equipment size – Modeling various building shapes, sizes and orientations and how they affect building equipment can result in discovering that a smaller HVAC system will do the trick.
2) Find areas of highest impact – Doing comparisons of ''what–ifs'' show the tipping point on the law of diminishing returns for energy decisions, and therefore allow facility managers to make decisions based on strategies with the highest energy impact.
3) Identify building performance relationships that don't make sense – Energy models allow facility managers to discover that the "if some is good, more is always better" rule doesn’t always add efficiency to a building.
When preparing an energy model - and there are several different types of software packages out there, some of them like the Department of Energy's eQuest, are available for free. They take into consideration three main sets of variables – weather and climate; energy and utility; and building components.