[Greenbuilding] Arnie's natural ventilation system

[Keith Winston]

The Ultimateaire machine, in night cooling mode, stops it's energy 
wheel. That means there is no longer a heat or humidity exchange 
function occurring. So it is simply expelling interior air, and bringing 
in fresh outside air. Looking at the load charts, it seems to me that 
the 200W for 200 cfm is when the unit is in ERV mode. Presumeably in 
night cooling mode there's some energy savings, though I don't know how 
much: it has an ECM motor also, so it ought to be fairly efficient (the 
efficiency differences between good motors tend to be on the order of 
2-4% or so, not 200W vs. 60W! I don't really see that information 
available, though.

Keith


Corwyn wrote:
> On Aug 6, 2006, at 21:31, George J. Nesbitt wrote:
>   
>> It is not clear to me if in cooling mode if the heat exchanger is 
>> bypassed, you wouldn't want to warm the incoming air.
>>     
>
> I would hope not.  The incoming air in cooling mode is cooled not 
> warmed by the outgoing air.  Just consider inside and outside switched 
> when winter changes to summer.
>
>   
>> But it is not the most efficient way to get ventilation cooling.
>> On high speed it uses 200W to get 200 cfm of outside air.
>> An air handler with a ECM and a Smartvent can move 400 cfm for only 
>> 60-80W (or less!).
>>     
>
> It should also be cooling for those 200W.
>
> Thank You Kindly,
>
> Corwyn
>
>
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-- 
Keith Winston
Earth Sun Energy Systems
3927 Madison St.
Hyattsville, MD 20781
301-980-6325
keith at earthsunenergy.com
www.EarthSunEnergy.com