[stevehull]

Further discussion re prior post.

There are large differences on heat/cooling depending on environment.

One of the worst places I had to contend with was an area in the Philippines that was subject to high humidity (80% almost all day - for months) and high winds. The design criteria was to maintain 50% humidity to protect sensitive electronics in a small "insulated" building with about 4-5 humans operating (mostly watching) the equipment. The both inside and outside walls were covered with foam sheets to prevent anyone outside listening to the goings on inside. VERY well insulated - perhaps R60 or so.

Two sturdy doors, with weather stripping, separated by about 5 feet comprised the entrance. But again, a lot of air leaks.

The combination of human water off gassing (mostly exhaled water, some perspiration) and the incredible imposed outside humidity load was daunting. The outside temperature was not bad - in the upper 80 - low 90s F. The electronics "heat" load was small as it was almost all solid state (no vacuum tubes). Probably a maximum of a few hundred watts (all CMOS technology).

But each person, at rest, contributes about 100-200 watts and five people is a substantial heat load in a 400 sq ft space. Also, no windows. A concrete block structure that one would think would have no air infiltration. Wrong! In retrospect, there were gaps in the manner to which the ceiling fit on top of the walls and this resulted in a large amount of water vapor infiltration. The significant winds essentially enlarged these small cracks as the windy side was pressurized and the down wind side had a slight vacuum.

Today, a small ERV would be helpful to remove moisture.

The smallest ac "through the wall unit" was found, but it cooled off the area too quickly and the inside became a soupy, wet, clammy and smelly mess. The electronics was literally failing as condensation would occur.

The solution came from a Navy submarine where tiny AC units are used to remove moisture from crew quarters where high density sleeping areas are. I don't recall the specifics, but it ran essentially all the time and removed a constant stream of water from the "shed". The problem I had was converting the power supply to accommodate the unit - subs are even stranger that aviation power supplies.

Frigid cold or blazing heat can be easily contended with, but high humidity at low temperature loads is tough.


Steve