Taking design cues from the ancient Roman hypocaust, Integrated Evaporative (IE) cooling is highly economical and capable of providing cool dry comfort even in humid climates.  It is well known that evaporative cooling is not suitable for humid climates, such as the southeastern United States.  Evaporative cooling is however, the least costly of common (active) cooling techniques.  There are two primary obstacles to employing evaporative cooling in the southeast:

• Additional (and undesirable) moisture in living spaces is the most notable disadvantage when IC is attempted in humid climates.
• The greatest limitation is the lack of sufficient wet bulb depression at night.  After the sun goes down the wet bulb and the dry bulb come much closer together and cooling potential is greatly diminished.

Many people are of the opinion that the relative humidity (RH) in the southeast is too great. This is true – but, mostly at night.  Most of the region has sufficiently low RH during the day – around 50% to 60% RH midday. This is low enough to yield wet bulb temps 10 to 12 degrees lower than ambient dry bulb.  This is significant cooling, but pointless if it can only be accomplished during the day.  In the southeast, nighttime temps in the summer are uncomfortably hot.  Integrated Evaporative (IE) cooling presents performance improvements that permit the use of evaporative cooling in warm and humid climates.  Other advances presented by this highly innovative concept are:

• Potential for air conditioned net-zero buildings via solar or other renewables.  
• Active heat gain mitigation. 
• High thermal inertia
• Process water recovery

A sub-scale prototype was constructed and tested in north Florida during the summer of 2005.  The prototype addressed the issue of insufficient (nighttime) wet bulb depression by decentralizing the evaporator and employing a high mass evaporative medium within the walls and floors, namely lava rock gravel.  Wet lava rock has an extraordinarily high thermal capacity.  This feature in conjunction with the high volume of wet lava rock within the floor and walls provides very high thermal mass.  High thermal mass affords a pronounced “cave effect” – allowing the system to "coast" over idle (nighttime) periods.  Needing to run the system only during the day is a doubling of cost savings.  Additionally, the prototype resolved the issue of unwelcomed additional moisture in living spaces by exhausting the moisture-laden process air outside the dwelling.  A bonus effect of “active insulation“ is provided by the IE configuration.  The active evaporator within the walls and floor of the IE system provides a 100% effective thermal barrier to heat infiltration through the walls and floor. Recovery of process water can be accomplished by utilizing geothermal energy available below grade at the site of construction.  Many warm and humid climates are within regions where ground temperatures near the surface are below summertime dew point temperatures.  Integrated Evaporative has the intrinsic potential to recover process water via geothermal condensation.  This will allow the process water to be condensed and reused.  This feature distinguishes the IE cooling system as the only cooling system with the potential to claim a positive water usage impact.

Please visit Inova Energy for more details and descriptive charts and images.  http://www.inovaenergy.com  The author encourages comments and website reviews.

That's great and all but considering the bulk of the cooling load of a decently designed and well-insulated moderate to high-mass building in the humid SE is predominantly latent load it seems like a lot of complexity for dealing with sensible load only. (And without an additional vapor barrier between the cooling channel and the interior space it would likely INCREASE the latent load from capillary wicking and vapor permeation through the concrete & stone.)

Using the ground under the slab as recharge also has diminishing returns over a season-long period too, if the sensible loads are very high, since the soil isn't a refractory material deep into the subsoil and it's temp will rise. This only works for relatively modest sensible loads over a whole summer.

The 83F interior temp touted for the 102F 49% RH day can be awfully miserable. The ventilation air has a dew point of ~79F, which would mean the 83F interior would be running a fungus & mold inducing totally stultifying 88% relative humidity. Sensible loads are easily managed by designing for low solar gain, insulation, and thermal mass. Minimizing ventilation rates to control latent loads when dew points are high are the key to keeping cooling energy requirements low.

This system is not unique in exhausting the moist process air to the exterior (Coolerado does the same), it's the recycling of process moisture using the earth as the condenser that's the distinguishing feature, but that's a feature I'm skeptical of from a full scale full season efficacy point of view. Build the house (or 5), live in it, have a third party track the indoor RH & temps as well as the outdoor RH, and do a full lifecycle cost analysis of the approach, then I'll believe.

It's a lot of complexity to build into the structure base on only a scale model's short term performance, compared to simply earth-coupling a reasonably designed low-gain higher-than-code-min insulated moderate to high-mass building to the same 65-70F subsoil Inova is using as the condenser.

I had some interest in semi-passive and solar dehumidification/cooling and my conclusion was that for very high humidities one should just minimize heat gain and air and vapor infiltration and then use an efficient conventional AC (geo or air source) when you can't get by with just ventilation/fans/thermal mass.

Thanks for your comments.  I am very interested in your opinions.  Pro or con, I want to know what others think.  
Thanks again.

Dana1, it's obvious you are very knowledgeable of the subject.  I appreciate your no-holds-barred appraisal.  I may however begin to spark some belief with one more thing.  Please go the the Inova website again http://www.inovaenergy.com/ and play the video on the homepage.  Notice that there is a 20 °F difference between intake and exhaust.  The RH for the day got no lower than 51%.  Get out a psychrometric chart and plot the temperature differences between intake and exhaust for dry bulb and wet bulb...or go here: http://www.sugartech.co.za/psychro/index.php  and input the intake and exhaust temps.  It appears that the prototype is cooling to the dew point.  I've heard a number of opinions about what's happening.  What's yours?

BTW, my original prototype included a latent heat component.  I built and tested a desiccant (living space) dehumidifier and a solar powered regenerator.  I used lithium chloride as the desiccant and it proved far more corrosive than I expected and became very problematic.  Anyway, I abandoned the regenerator after I saw how well the evaporator performed.  

Thanks again for taking the time to view my website and posting your comments.