[Equest-users] VAV vs 4-pipe Fan Coils (Heating Energy Consumption)

[Ana N.]

Hello e-quest users,
 
When I run a simulation with the standard VAV w/ reheat and compare it to the 4-pipe fan coil system, I get a huge savings in heating energy. I would expect some savings due to reheat, but not as much I am getting (about 50% savings in heating energy). For the VAV, I am controlling the cooling coil so it is on WARMEST from 55 to 60F. The building is in climate zone 5A and heating energy makes up a significant portion of total energy consumption. 
 
Has anyone seen such a high savings in heating energy when switching from the VAV w/reheat to the 4-pipe fan coils? 
 
I also run a quick test for a simplified building geometry (similar building size and occupancy type as my project) using WIZARD and found that, if I use version 3.64 e-quest, switching from the VAV w/reheat to the 4-pipe fan coil does NOT give me much savings in heating energy.  However, if I run the same simplified model using 3.61 e-quest (WIZARD), I get very high savings in heating energy, similar to what I have in my project. 
Can anyone shed some light on what might be happening here?
 
 
If anybody has some input, it would be appreciated.
 
Regards,
 
Ana Davidovic/Mechanical Engineer 		 	   		  
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