Evaporative Cooler Ducting Design

The boiler room on my ship was 186 degrees on the Fahrenheit Thermometer hanging in the forced air inlet. This was the most comfortable place on the top plates of the Fire-room. Other places got considerably hotter. If it were not for the moving air and the sweat soaking your overalls you could cook very easily.

We also had lots of insulation on all the steam machinery to improve compartment habitability. It was all Asbestos.

BAB

Forgive me for having a hard time with this. Sweat soaked overalls means the humidity is pretty high, since if humidity were low at 185 F it would evaporate pretty rapidly. Soaked clothes do not allow airflow.

Check out this Canadian site that using what they call Humidex. http://images.ccohs.ca/oshanswers/Chart025.gif

The highest category they list is described as imminent risk of heat stroke. At, or above 70 % relative humidity anything above 37 C falls in that category. At just 50% relative humidity, anything above 40 C is considered imminent risk of heat stroke.

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Those acutely seem pretty conservative to me, but working conditions that exceed those limits by, at least, more than 40 degrees Centigrade or more than 72 degrees Fahrenheit is amazing.

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Steam plants are notoriously humid. Steam room manufacturers limit their temps to far less than the range you are talking about. I can tell you that being in a steam room that is at even 110 F feels like you are being scalded if you move to quickly .

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Something doesn't add up here. Did I miss a coordinate calibration of thermometers?

As I've said, I too have a hard time with this!

So I did a little research. Most of what I found was referring to coal and oil-fired ships of the late 1800's and early 1900's. They all agreed that it was dirty miserable work, but all the references to boiler (Fire) room temperature I found were in the range from 110-120°F.

Even those temperatures are unbearable to me, but believable. Now 185 or higher, NO WAY! I can easily imagine a thermometer in a boiler room placed in such a position as to receive radiant heat from nearby pipes, etc. so it would indicate a much higher temperature than the actual air temperature. If I had to work in such a place, I too would exaggerate the severity of the working conditions.

Andy and BAB: I simply do NOT believe you!

In fact, I came from Colorado to the central valley of California as a teenager in 1954. I had never heard of temperatures in the 110-115° range! The very next summer I got a job washing dishes at a YMCA camp at 6500 feet altitude in the northern Sierra Nevada. $10 a week plus room and board with comfortable temperatures was WAY better than $40 a week down in the valley. I got promoted to other jobs (camp maintenance) and better pay the following several summers, and never regretted escaping the valley heat.

I have no problems with you not believing us.

I know how it was.

You simply are overly temperature sensitive, so that means "it does not ever happen" in your eyes....

Your problem not mine.

Have a nice "cool" day wherever you are.....

You are missing a lot.....

Before, no thought was given to working conditions other than to supply salt tablets, and as I mentioned before, I once got heat stroke, its not funny.....its a fairly recent innovation to think about working conditions....

But do understand, given time, our body actually adjusts to the conditions over the first few months of exposure.

After a few months, I remember freezing my nuts off in the air conditioned switchboard, where it was "only" 40°C.....far too cold without proper clothing on!!!

You have to have lived in the tropics for quite some time to understand better.....I love them, but the white man has often died there too over the years....

Even though I am blond and fair skinned, (I don't ever sunbathe, ever, like some of the idiots did!!), but once I am tanned (give me 6 months of just walking around for short periods in the sun!), I can handle tropical sun and heat better than anyone else I have ever met!!! It just takes me months.

You can get Sunburn in Singapore just by walking around in a white shirt without any sun blocker on (me, new out from the UK) in 5 minutes in the midday sun!! Painfully, though I do know a good fix for Sunburn!!

The people who tan easily, eventually mostly got pigment problems after 6 months or so, big white patches of skin on a dark brown background. It looked like an awful skin disease!! They had to cover up and not go in the Sun for a year or so, otherwise it just got worse.

This is NOT sunburn by the way....but basically the result of too much sun over a longer period.

That you do not understand what some of us are saying, the truth, is not our problem. WE KNOW HOW IT WAS.

Why do you need to "understand" it?

Thats what foxes me......

Go and live in a tropical country for 6 months (not Singapore anymore, its too modern nowadays!). THEN you will understand.....

Find a steam driven ship and go in the boiler room while underway......

You may collapse.....wear a crash helmet!!!

Andy, you misunderstand my curiosity. I don't think you are lying to me. At first I thought you were messing around, but you cleared that up in your next response. If I thought you were trying to mislead me, there wouldn't be much to discuss.

My interest; the reason I am eager to understand is that I am going on the assumption you are not making things up. The conditions you note, and that have been corroborated by at least one other seem extraordinary. I am trying to wrap my head around how a heat producing human body can possibly stay below 105 F when in 185 F with over 70% RH for more than a few minutes.

I'm not questioning your integrity. What has me prodding is the thermodynamics.

Sorry, I misunderstood your interest.

As you can well understand, you sweat buckets, so you go and stand under a fresh air fan occasionally where its only 50°C, almost cold!

There are hotter and cooler areas in the boiler room, you learn where they are!

You drink vast quantities of fluids, mostly water, but not cold drinks or you get the "sh*ts". Having the "Sh*ts" can be an event you endure several times a week, though once you are empty, it stops!! You don't feel bad, just "cleaned out!"

Funnily enough, outside of the hot boiler and engine rooms, you sweat very little after a few months, you are acclimatised!

BUT YOU FREEZE YOUR BUTT OFF IN EUROPE FOR THE NEXT WINTER OR TWO WHEN YOU GET BACK!! Even in the UK summer you need warm clothes on....

It takes far longer to get used to Europe again than getting used to the tropics. I have NO idea why that is......

In the boiler room, you handle tools with leather gloves on only, or you would get burnt, as the metal picks up the ambient temperature VERY quickly.

You only go once into the engine room with a gold/silver chain around your neck with say a St. Christopher on it.

(Which, by the way, is why you have two ID disks/Tags issued to wear, one of metal and one of a type of plastic.....which does not warm up, is light and sticks to your skin for boiler room work for example...)

As long as he St. Christopher is "glued" to your skin with sweat, no problem! But if while working, it comes "unstuck", it quickly heats up and its MOST painful to have it back on your skin again!! A red semi "burn" is the result usually....I could see the impression of ST. Christopher quite clearly for an hour or so....

As I said, you only do it once!!

While working on a Calorifier, I accidentally put my bare belly against the steam valve thermostat, you could read the makers name for more than a week till it healed up. I had "Branded" myself in two meanings of the word!!

Scabs on wounds must be carefully watched as they can get "mildew" on them, which can be dangerous. When it happens, you need to remove the scab and bleed a bit, every 2 or 3 days....each time it heals a little bit more, but you always have a scar at the end.....

If I was doing it nowadays, I would handle it daily with TCP or similar!! No mildew and no scars!! I didn't know then how fantastic TCP is....for humans and pets with open wounds....

You have to get your cold weather uniforms (Navy blue/Black) cleaned about once a month to get the mildew off them...even though you hadn't had them on.....

In Singapore, I have lived with A/C and without it. I preferred without very definitely....I feel A/C is just not healthy, I always got head colds.....blowing around dust and bugs someone once said to me!!

Thats over 85°C.....not cool!!

And as you rightly said, that was not the hottest place either!!!

We could have been on the same ship!!!

When I think back to the "physical" times on a coal fired ship at the beginning of the last century, how hot it was and how physical the work was.......we had it easy!!!

The Diesel "Landlubbers" of today haven't a clue!!!!

Taking advantage of a resource like low relative humidity in a hot climate doesn't really indicate an especially noteworthy concern for energy/money. Failing to utilize the inexpensive method in order to conform with the more complicated and expensive norm is difficult to distinguish from profligate squandering.

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It does seem like a fairly basic modification of the typical evaporative cooler design could improve the performance significantly. Simply said, a large air to air heat exchanger in which heat from low humidity air for indoors is transferred to cool high humidity outside air, would provide cool dry air for indoors.

Placing these spot coolers in the notable hot spots in the house, like behind the refrigerator, in the bathroom and laundry room, and places where electronics might add heat load, would make the heat transfer far easier.

If the exchangers were made tall and smooth, natural circulation could be utilized. Fans might not even be necessary outside, if a fine mist were sprayed downward inside near the top of a tall insulated tube.

The heat exchangers don't need to be robust or expensive since any pressure differential is negligible. Aluminum flashing sealed with construction glue could easily form tall low restriction channels for low cost.

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Perhaps I am just not aware of what is being used/ available. Does anyone know of residential evaporative coolers that use air to air heat exchangers?

I've thought of that heat exchanger concept to avoid the humidity, but I've never seen it done. That of course does not mean it hasn't been done somewhere.

...and I've thought lots of times about the refrigerator heat. Since most homes (here at least) have a specific spot where the refrigerator must be, it would be a simple matter, for homes like mine that have a crawl space, to include a hollow section of wall behind the refrigerator to duct the heat up.

Retrofitting with diy heat pipes insulated in the traversed space is even an option.....hmm sounds like a weekend project and testing is in order.

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https://m.youtube.com/watch?v=LU4eynU6R-8

Interesting link!

One problem, for eliminating the refrigerator heat, is that the place where the heat is extracted from the heat pipe must be cooler than the place where the heat enters the pipe. The working fluid must evaporate fairly rapidly at the hot region for the vapors to carry the energy to the condensation region. Most of the time, the attic is much warmer than the house, so we can't dump the heat there.

My refrigerator is pretty new (a year or two), and I can only measure a few degrees C difference between the warmest place behind the refrigerator and the room. There was a LOT more difference with my prior refrigerator.

The more I think about it, the more I think it's not worth the effort!

Very interesting videos from RICH ALLEN, that makes such units DIYable, cheap, strongly built, easy to repair and seemingly quite effective.

I never did like the glass ones that get sold here, due to price and possible breakage in a hail storm. Even if the glass ones are more effective.....

The money saved in a DIY version can often be put to good use in building more of them!!!

I am not sure how they would help out friend with his barbecue and A/C problems though, am I missing something obvious?

The glass ones you are talking about (correct me if I am wrong) are evacuated solar tubes, used to heat air or water.

The heat pipes from the video can be a very effective heat transfer system. Because there is a phase change inside, and the system is sealed, if the correct fluid is used at close to the correct pressure, relatively high rates of heat transfer can be achieved for a given delta T. This is a system employed in cooling satellites and computer chips. I suspect that over greater distances the system will work better with a dedicated hot tube and cold tube, and with the heat transferred in as far below the heat transferred out as possible, but they can be made to work in zero gravity or against what natural circulation would normally dictate with the use of wicks.

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The idea could be applied in a very dry place by installing spot coolers using these heat pipes with fins for surface area at the places that typically add heat to the interior spaces; refrigerator, freezer, bathrooms, extensive electronics, etc. The heat pipe would be insulated as it passed through walls to the outside. Outside, another set of fins attached to the other end of the tubes and a very fine mister and possibly a fan on a thermostat....all in the shade, would draw heat from the hottest places in the house.

There are a couple advantages that could be realized. First, the inside air is made cooler, without increasing relative humidity, which means it can still feel comfortable without the temperature being as low. Second, the cooling effect does not depend on air exchange, so that ventilation can be controlled independently of cooling.

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It would be harder to make it work in a more humid climate.

Carrying that a step further, I visualize a swamp cooler modified so the humid air exhausts to the outside. It could probably work with a smaller blower or a lower speed. A set of those heat pipes, each with an elbow, would have the cool ends immersed in the pool of water at the bottom of the swamp cooler (no fins required), go through the wall and down along the wall. a second small blower would circulate inside air over the warm ends (preferably with fins) of the heat pipes, cooling that air and vaporizing the acetone or other working fluid. These might be cool enough to require a collector for condensation, but perhaps not in the desert climate of Las Vegas.

Ahhhh, right you are. The grill is indeed outside. I had contorted the house into some form of a torroid like shape with the cooler intake and grill exhaust in close proximity on opposing inner wall. Now that I think about it, that would be a pretty odd design.

Since the grill is outside, if a hood and chimney are properly placed, it probably doesn't need a fan to start the natural circulation.

Thank you for the update on the Hood/Chimney idea.

I will look into that. I may be able to get a professional restaurant hood from one of our remodel jobs, so I will keep an eye out for one.

Something just caught my eye in your original post. The third bullet point in the list of expected remarks:

".. Use your A/C when you BBQ (Not economical to turn on and off for an hour)..."

What did you mean by the portion in parentheses? There are some very prevalent misconceptions about hvac use. You are obviously interested and involved in the subject, so it is only fair to insure you aren't duped.

I suspect the "loss of economy" from switching from a swamp cooler air to AC air for just a few hours happens with the moistened air taking many a BTU of energy to remove the added water vapor while attempting to lower the temperature. I'm certain that there will be RH conditions that this will be an inconsequential difference. Particularly when one compares the added heat load of cooking inside instead of outside of the the home.

A swamp cooler normally has a single fan, while an A/C has two fans and a compressor, and it is the compressor that uses the majority of the energy. The A/C costs roughly an order of magnitude more than a swamp cooler for the same amount of time.

Of course you are absolutely correct that the A/C will be removing a lot of water from the air, but it is precisely that removal of water, just as much as the cooling of temperature, that makes it comfortable in an air conditioned room.

If the AC is turned on when the swamp cooler is turned off, then there shouldn't be a need to reduce the temperature, only maintain it.

Yes moisture will condense on the coils and lower the rh. That will make it actually feel cooler at the same temperature, so the AC might not even need to maintain the same temp as the swamp cooler....it might be fine a few degrees above.

You have a good point about heat load from cooking.

One way we have reduced the amount of warmed air when cooking on a stove top, is the induction units we have had now about 9 years or so at home, as basically, only the pot gets hot and only very small amounts of the surrounding air are warmed.

We take them with when we go camping in southern Europe in the summer, when temperatures between 40° and 50°C are common, as our van has no A/C (simply some fans 12VDC and 230VAC removing warm air at the top and sides), so we do not want to add any heat to that!

We also can take the induction units outside on a longer cable to reduce the effects even further if needed.

Cooking on gas (when a campsite has no mains available for example) demonstrates VERY quickly what a huge reduction in heat we have achieved....

I can only recommend induction strongly for any household for speed, efficiency and cost savings with electricity.

I will do my best to explain my thoughts,

Getting ready to start the BBQ I turn off E/C so as to not pull smoke into the house.

I really don't want to turn on the A/C because it will only run for about 30 minutes while the heavy smoke is coming out of the BBQ.

My thoughts are about the wear and tear of a cold start on the A/C and only running it for a short period of time and then turning it off and then re-starting the E/C and the cost of running the A/C. (remember, I'm cheap).

There will come a time during the summer that we will turn off the E/C and run only the A/C because the outside temperature exceeds the capability of the E/C to cool the house.

Here are a few technical points on the home that I have seen questions on.

• My home is a manufactured house.
• The structure is insulated 100% on the exterior.
• The exterior walls are 2" x 6" with R-19 fiberglass batts.
• The roof is the ceiling. No attic. Insulated with R-30 fiberglass batts.
• Interior walls are not insulated.
• Under the house is insulated with R-30 fiberglass batts.
• Roofing shingles are a white / grey color.
• The home exterior is painted a dark green. I will be painting it a light tan color soon.
• The windows aren't in the best condition. The seal isn't the best. However that doesn't matter with the E/C.

I know the color of the house does affect the indoor temperature so that is why I will be painting it, and the green color is disgusting.

I hope this info helps resolve some of your questions. Have a good day and thank you.

A very reasonable explanation for not wanting to turn on the AC. There is this pervasive myth, that I have come across in otherwise logical people that holds a belief that keeping the AC running for the four hours expected to be away from the house, will be less expensive than turning it off and turning it back on when they get back. The stated reason when pressed is typically that they believe the AC will have to work harder to get it cool again than it would have maintaining the cool temp. I think there are some unhelpful analogies being drawn to keeping a car at speed, perhaps.

Obviously you aren't that easily duped.

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Painting your exterior walls a lighter color is a good idea. It would be a good idea to run some tests on some samples. Some colors that look lighter may actually get hotter. Have you ever walked barefoot on light colored sand or nearly white concrete in the summer and found it surprisingly hot? Even if a surface reflects 95% of the inbound sunlight, if it absorbs more energy than it is losing to radiation, convection and conduction, the temperature will increase. There is a lot of interesting material on selective surfaces if you need some reading material, but it will probably be easier to test samples for an extended period.

What color is your roof? There are readily available cool roof paints.

Overhangs over the east and west windows as well as the south windows windows can be very beneficial. Shade in general from tall vegetation or shade sails can offer huge improvements.

I'm not suggesting you haven't considered these ideas already, just think of this as some ideas being thrown around from another person who holds cheap in high esteem.

How modern is the insulation/house?

You mention bad window seals, which makes me think that the house is not insulated to modern standards. I could be wrong of course......but anything over 15-20 years old is not a modern standard here. Some might say even less. Our 7 year old insulation is not the modern standard any longer....

The outside colour will naturally play a role just as you say, but is probably not the most important aspect that needs to be corrected first......

What does play a role is a) the type of insulation, b) that the insulation is in a good condition and is not wet or damp c) the thickness of the insulation.d) You need a sealing plastic skin, that also does not allow damp through, holding the roof insulation in place, and not allowing air through!

Also, warm air rises. If there are places where it can leak out, especially "high up", (you need a special IR camera to see that clearly), it will then "suck in" more air below. This is only one of the reasons you should have good window seals....that way you decide when the air needs changing, not the house!! It does not even have to be much air movement.......to still warm the house up a lot.

It may even be "related" to the "chimney effect"....

You can tell how bad the leaks are to a degree, by closing all the house windows, but leaving the internal doors open. Then open a window downstairs a crack and if you know a smoker, get him to puff a few clouds just outside that window on a calm day. If they get drawn in, the house is leaking air upstairs!! Its not very scientific, but it can show a trend.....even if you see no effect, that does not rule it out completely.....

What appears to be the normal sort of insulation material here is a flame retarded expanded plastic foam, like Styrofoam but does not burn. I have forgotten the trade name, for all the outside walls....in the roof area, we used Stone wool (my translation!) and used about a foot thickness.....it seems to work well.

As I mentioned before, we can get a 36° to 40°C days in summer. We let the house air/cool overnight, lower the sun shades on the east and south side and close all the windows as the sun starts heating up the outside, and basically the house stays cool the whole day, dropping the west side roller shades when needed........people who come in think we have the A/C on!!! It stays significantly cooler than outside the whole day long....often a 15°C difference to outside.....

But do realise, I am no expert....

Fill in the blanks.

Sure, give credit where credit is due. After all it is far more horse mane... er, humane, than beating a live horse.

Near as I can tell, the last 43 posts have nothing to do with "Evaporative Cooler Ducting Design", but rather a lot to do with insulating houses half way around the world and the climatic conditions in those locations.

But, that's just me.

Aw, come on. It isn't just you. You hardly have contributed to the tangential meander at all. There was that part about icey, uphill commutes to and from school, and the bit about some ward in charge of beating dead whores, but not much else.

Climates and insulation do kind of fit in a square round about way, as it has to do with the underlying goal and the specifics of the locale.

Being protected by sweat soaked overalls from egg poaching temperatures is pretty far off track, though, and I certainly bear some responsibility for that. I'm not sure it's deserving of its own separate entry, do you? If not, are you suggesting/asking we not talk about these things where you are likely to notice?

Not at all.

We (I, also) go off topic all the time. The "uphill, in the snow" was also way out there.

But, I just find it fun to throw the dead horse into the mix when a subject (in this case, far removed from venting a BBQ) takes on a life of its own.

I'd be interested in hearing what Bryan comes up with.

Cheers.