Constant-temperature dehumidification

[Joe Fischer]

Unfortunately you'll catch up.

Buildings today seem to be getting away from natural and passive systems and moving toward more complex active systems that require energy. My house has transoms, but they were painted shut when A/C became available and never used again.

In 1943 I was assistant manager of an 800 seat theater, and it had a passive warm weather ventilation system that I had no appreciation for at the time. The roof had a center section that was higher, and windows tilted in on both side walls of that high section. There were huge vent ducts which were not noticeable with floor grilles. With a large crowd, the heat generated per person increased the natural convection out those top windows, drawing air in the hidden floor ducts. On really hot days there were huge low speed fans in those ducts, but they rarely were needed.

If removing moisture with dehumidifiers for a family of four in a home in winter is an engineering problem in the classroom, then there a lot of homes that are apparently too moist, because there are few if any dehumidifiers used in homes other than in basements or laundry rooms.

There was a program on TV a few years ago that showed a southern home with the same type of natural ventilation as the theater I mentioned. And there has been some mention that some pyramids were constructed the same way.

Passive solar and natural convection ventilation systems seem to have been replaced by more positive systems that require energy, but that do provide more capacity at any time (as long as the grid is up).

Joe Fischer

[nicksanspam]

Perhaps you should unglue them. The post-occupation French word for "transom" is "Wasistdas."

Cool. Where did the air come from?

Nick

[wmbjk]

No, that's just what you *believe*.

I predict that you won't believe the Mayo Clinic either. The fact is that the cause of the common cold has been known for a long time. Unfortunately, a lot of people insist on spreading nonsense instead.

Wayne

[Joe Fischer]

From large inverted J ducts on the roof, like those seen on ships.

Everything was so automatic, needing very little attention, even though I was the only person besides the cashier and projectionists there, nothing required my intervention except opening the top windows seasonally and tapping on the air traps on the low pressure steam radiators to get steam to them occasionally in heating season.

A freeway took the site in 1962.

Joe Fischer

[Joe Fischer]

You gave a wiki link and had to switch to Mayo. :-)

As much as any medical institution, I do, but nobody is perfect.

And those of us who know the most frequent cause of head colds don't get them unless we neglect to maintain the steam humidifier, or get chilled, or not get enough sleep, or get too close to somebody who has a cold and doesn't try to contain the germs.

I didn't say that germs are not involved, in fact, I said germs are involved and that a steam humidifier does a lot to prevent irritation of sensitive membranes in the airway.

Apparently you assumed Mayo Clinic to be more perfect than they themselves believe, as shown;

from your link.

I do other things besides run the humidifier, if I get chilled or get a ticklish throat, I put salt in my mouth in lieu of gargling salt water, I take an extra vitamin pill, and I moisten my mouth and breath in through my mouth and out my nose, which puts moist air across the dry membranes of both throat and nose.

The important thing is to try to do something about it before it gets to the point of being a full blown head cold. I can only remember the last 75 winters, of which only the last 55 apply to my suggestion, as the places I lived before that didn't have forced air heat. If I run the steam humidifier to maintain

50 percent relative humidity at night, that helps prevent not only irritated nasal membranes, but also migration of germs from carpet and fabrics drying out. Fifty percent relativity is just an easy to maintain number, possibly in a clean house any constant relative humidity that does not irritate the sensitive nasal or airway passages would do as well. (Constant RH!)

JoeFischer

[modervador]

This would be easily explained if it was found that Vermonters have a higher tendency to sneeze on each other, not wash hands often enough, etc. Or maybe it's got nothing to do with Vermonters' habits or their weather. I've lived in several climates and I've found that I'm more likely to get sick when I've been around sick and/or contagious people. Maybe it's them New Yawkers who come up to Vermont to ski that bring their strange city germs.

I wonder what the rate of headcolds is among those of the "dry south" compared to the "humid south"? This may shed light on the topic.

%MOD%

[modervador]

The latter is a factor not to be underestimated.

I once had a schoolteacher who insisted on keeping the window next to me partly open all winter. Even when I was fighting a cold, he refused to allow any change in seating arrangement or to let me wear my overcoat (claiming the latter was disrespectful). There was no debating his infallible logic. "Since you like science so much," he'd say, "you should already know that cold, fresh air doesn't have any germs in it and can't make you sick." It sure as hell seemed to prolong my miserable recovery.

Now that I think about it, since I've been out of school and drink more beer, I haven't been sick nearly as often.

%MOD%

[Joe Fischer]

Sure it's the beer, which seems to also make % look like a letter character. :-)

It is pretty well known that A/C _can_ dry air out enough to irritate throats and nasal airways, but it is not the dry air, it is the rapid change indoors where there is migration of irritants and germs into the air that seems to be the problem.

The only head cold I had in two years in Pasadena was in the pool house I rented and used the gas wall heater. I had to move out it was such a miserable experience. The rest of the two years I rented a room by the week in the small hotel on the corner in front of the popular bar and club "Icehouse" in 1964 and 1965. It had steam heat, and had very constant temperature and humidity and was very clean.

My experiences of waking up with burning throat and sinus if I don't run the steam humidifier on a night when it is below freezing, and some relief if I run the hot water in the shower and breathe the hot mist, is enough proof for me.

There is no way that doctors don't know that the heating season causes head colds, but the things that need repeated most, like "keep the humidity constant" are the things not mentioned after a while, just like the most popular selling item in a store is never reordered.

Passive constant temperature homes need lots of mass, and a heating system that controls humidity. Furnace companies would not have designed furnaces and stoves with water tanks and circulating mechanisms if there was not a known benefit from keeping humidity from the wide swings. While protecting wood and fabrics, there is an often repeated suggestion, "set a can of water on the stove", which seems to suggest it is widely known that air drying out causes irritated airways and head colds. Humidity needs to be kept as close to 50 percent as possible, and that means adding a lot of water in heating season, even if it takes 1060 BTU per pound to vaporize it. Preservation of wood and fabric would be enough to make the extra energy used worth it, if the furniture needs replaced because it dries out and cracks is not efficiency.

Who named this thread with "dehumidification"?

Joe Fischer

[nicksanspam]

Not if your house is airtight.

Me.

Nick

[Joe Fischer]

Oh, no, don't tell me you think that air can be warmed up 50 or 60 degrees and still have the same relative humidity without adding water. You demonstrated knowledge of standards suggestions for changing air, and your premise could only be valid if there were no change of air at all. Forget the water vapor and heat that people give off, it isn't enough to make a difference unless it is dozens or hundreds in a building.

It figures. :-)

In really thought your main premise was that it doesn't pay to humidify if the cost of fuel for the latent heat of vaporization is considered. If you live in an ivy tower with thick walls, that may reduce the temperature and humidity swings. I lived in permanent housing at Randolph Field (now Randolph Air Force Base) in all of 1948, and the walls were more than 24 inches thick with poured concrete floors, and even though the outdoor temperature was cold enough at night to freeze rain on AT6 propellers and 80 by noon, the temperature inside didn't change 2 degrees. But houses are built in the worst way possible to maintain constant temperature without considerable heat added, and if heat is added, water must be added to retain constant relative humidity, at least to the extent that heat is added to raise migrating cold air to indoor temperature.

Joe Fischer Quit adding groups!

[nicksanspam]

I never wrote that. Are you delusional again? :-)

YOUR premise that winter humidification saves energy could only be valid in that case.

Agreed, for non-airtight houses, in really thought :-)

Nick

[Stormin Mormon]

And what effect did that have, insulating the thermometer by wrapping the bulb with dry cotton? Seems like it would read the temperature much faster if the bulb wasn't insulated.

[Joe Fischer]

You have a communication problem, if you want to specify a house that will never be built, just say so.

I really thought you were serious.

My premise is that protection of wood and fabrics and health is part of any equation about costs.

Try your math on adding enough water to maintain constant 50 percent relative humidity to change 10,000 cubic feet of air every two hours (with zero people in the house).

Joe Fischer No pets or aquariums either.

[Joe Fischer]

Sorry, I didn't say the cotton was dry, it may have been wet with water or even alcohol, I am not a trained weather man. :-) I assume he was checking dew point, but I am not certain. Moist air is lighter than dry air, so dew point was important in several ways for Army Air Force weather forecasting.

Joe Fischer

[Eeyore]

Airitght houses are very unhealthy.

Graham

[amde]

I know someone who has a house that is so airtight that it came with an air exchanger. Crazy..

[Rod Speed]

Its wrapped in wet cotton, thats what the wet bulb temperature is.

Yes, but its wet cotton, not dry.

[Solar Flare]

Hot water huymidification techniques increase germ breeding and are not recommended for sinus problems anymore. Welcome to the 90's

[Anthony Matonak]

I know someone who has a house that is so drafty they spend huge amounts of money on heating and cooling. Crazy...

Anthony

[Solar Flare]

I doubt the cool air came from ducts on the roof without powered ventilation.