[Greenbuilding] Central vs window AC

[Eli Talking]

I am following this thread with great interest.  It relates to my specific situation.  

We have some people who choose to live without ac.  Generally, I conclude that they acclimate to the higher humidity.  I have one house I designed with suspended concrete slab in the middle.  This lowers the mean radiant temperature at the peak summer day.  Therefore, they have comfort at a higher air temp and perhaps a lower relative humidity as a result.  This household chooses to keep windows open during the day.  

My own home which is on the way but not completed at being a tight house, I cool the house by night flushing.  Yeah, this results in higher relative humidity.  I do not have a large mass such as described above.  However, the typical mass will hold heat and humidity.  I have noticed that when it gets too cold for our preferences, I close the house up and the temperature will rise even though the outdoor temp is colder than indoor temp.   I assume this is because the air temp is cooling the mass from the surface.  When the source of cooling is removed, the stored energy below the surface raises the air temp.  Of course there are also internal heat sources also, (bodies, refrigerator, stove).  

The issue about humidity is what I want to better control.  Night flushing for cooling is very affective in my rural setting (no heat island).  If air temp will go into 60’sF, I can cool house to 70F and keep below 80, even into outdoor peak temp of upper 90s.  I recorded 78.9F when 103F outside, the highest temp I have ever seen here.  I have made many improvements in tighness since that reading.  However, I am sure the humidity was high.  I was not measuring humidity at the time.  Even with the higher humidity, when I walk into the house with outdoor air in the 90s, it is much more comfortable.  I have not experienced the draconian consequences discussed in the link:
http://www.greenbuildingadvisor.com/blogs/dept/musings/belgian-passivhaus-rendered-uninhabitable-bad-indoor-air
The high humidity goes away when dryer atmospheric conditions occur.  

It seems that refrigerant systems are the only vetted systems available to dehumidify. If a house is very tight where night flushing can keep cool enough for comfort temp, which is better for dehumidification: small ac or dehumidifier?  

I am still working through the great link that Nick Pine provided about the parameters for comfort.  
http://www.scribd.com/doc/26886870/HVAC-Handbook-Thermal-Comfort-by-INNOVA#download

Eli 


 
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