Earth Berming and Optimize Energy Performance

Hi Marc,

Currently most energy modeling softwares used for Energy and Atmosphere Credit 1, Optimize Energy Efficiency credit documentation have very limited options to directly model energy savings from strategies like earth berms. This would include models created by most softwares like eQuest, Trane's Trace, Carrier's HAP (Hourly Analysis Program) or Energy 10. So, you would need to work around the inputs permissible by the softwares.

According to Appendix G, the baseline case and design case need the same area for above grade wall construction and below grade wall construction. I suggest, you can still try to demonstrate the benefits with a different method - having two different models and comparing them. In the first model you could model both the baseline case and the design case without the earth berms and determine the savings. Then, you can model the proposed case again separately considering the earth berms in below grade wall with relevant values and check the higher percentage of savings now.

Alternatively, you could do the reverse. First model the baseline case and design case with the earth berm. Then, model the baseline case separately without the earth berms.

Mainly you would end up changing some walls from above grade to below grade or vice versa. You would also need to document your method as a reasonable way to compare savings between the two cases. This way the benefits of using earth berms by reduced heat transmission of the building envelope between exterior and interiors can be quantified and modeled.

There is another way, though a little longer and more complicated. You can use other softwares which can help in quantifying the benefits of having an earth berm structure against a conventional above ground structure. FlexPDE helps compute the thermal field of the building envelope and the soil. Through this you can calculate the temperature of the soil surface. This can then be used as an input in Energy Plus for the energy balance calculations which can give the building's total energy demand.