Swamp Cooler to Refrigeration A/C

[Abby Normal]

No Nick

I pointed out the flaws in the numbers you 'dreamed up' with real numbers.

[nicksanspam]

Wrong again :-)

Nick

[Abby Normal]

"Ever time they are right I just say they are wrong, I dream up bullshit numbers after a hit from my bong"

[Rod Speed]

Odd that groups.google cant actually find anyone saying that except you.

[Abby Normal]

Why yes troll king, I coined that prose.

[Abby Normal]

Where as all you can come up with is 'blotto' and 'wet paper bags'

[Abby Normal]

You might try a different configuration with better controls, eg turn on the swamp to cool recirculated house air when the indoor temp rises to

80 F and turn on a small exhaust fan when the indoor RH rises to 65%.

This works in Melbourne Australia...

Nick

Lol it sounds like the ozzies were just pressurizing the house then and letting it 'efiltrate out' where ever it could and exhaust fans turned on when humidity hit 65%. Funny how if you followed a constant wet bulb line from 28C/35% it pretty much hits 22C/65%. But you do not have much faith in wet bulb lines because they don't fit your 'physics' lol.

Does not sound like your 'humidify the indoor air scheme' and turn on the exhaust fan at all, the swamp cooler sure sounds like it was working normal treating the outside air, except there was no obvious relief opening. Lol so they used power to run an exhaust fan rather than open a window. Way to go Nick you saved them some energy there.

[nicksanspam]

There was no pressurization.

No. It was exactly the scheme I suggested.

Nick

[Abby Normal]

I just don't see the part where the ozzies mentioned recirculating air.

[nicksanspam]

That wasn't explicitly stated above, but I know the ozzie in question, and we've discussed his experiment in detail, and that's what he did.

Nick

[Abby Normal]

[nicksanspam]

An indirect clarification from the ozzie:

Ok, I've read the posts on this newsgroup, and I do have to wonder about the sort of people who have time to pointlessly argue and flame each other but not enough time to learn the basic physics about their topic of interest. I'm certainly not interested in posting directly to the group.

That's correct...

We have a 'closed room' with an evaporative cooler in the room. A duct taped box fan sits in the window and is run whenever the humidity rises above 60%. Conceptually it is the same as forcing the air into the house, except that it is demand driven, which seems to make it more efficient. The room also seems to cool down faster, as we use the existing somewhat cooler air for cooling first, and perhaps we heat exchange the air with the walls and doors as fresh air leaks in.

Two potential improvements: 1) exhaust house air to an attic ("upducts") or some other cavity bordering an exterior surface, eg a garage or sunspace or storage space, and thereby reduce the usual conductive heatflow from the warmer outdoor air into the living space, or 2) use a humidistat and a reversible fan like Lasko's $55 2155A 16" window fan (90 watts at 2470 cfm on high speed) and Grainger's 2A179 $88.15 programmable cycle timer and its $4.37 5X852 octal socket to periodically reverse the fan direction when it needs to run, making a "Shurcliff lung" that turns all the cracks and crevices in the house envelope into bidirectional air-air heat exchangers.

We need to get rid of moisture vapor, but it's more efficient to do that using cooled vs uncooled outdoor air. For optimal ventilation, run the fan long enough to actually move some outdoor air in through the wall cavities (vs moving a smaller amount of cavity air back and forth), but not so long that the wall thermal mass heats all the way to the outdoor air temp on the intake cycle.

What complete crap (do you normally spout unsubstantiated rubbish?). Evap coolers outsell heat pumps about 3 to 1 I'd be guessing. Every new house seems to come with a roof mount evap cooler.

I wonder whether people are thinking of Melbourne, FL. (Perhaps these illiterates don't actually read before posting.)

Any time you move air around you are creating a pressure difference. I'm not sure what you are claiming here.

I believe Abby was thinking the swamp cooler was trying to push outdoor air into the living space vs recirculating indoor air, ie "pressurizing" the living space. But the exhaust fan would DEpressurize the living space...

The reason the windows are closed is because extra air coming in through an open window would simply add more heat, which we would have to remove. Once we are cooling enough to overcome infiltration extra air has no long term benefit. Commercial systems attempt to overcome this with a very big blower. Blowers are inefficient and noisy.

Nick

[Abby Normal]

No not pointlessly flaming

Just saying that they ozzies made a big point about stating the windows were closed. With any air conditioning except traditional swamp cooler you would want the windows closed.

My interpretation of the post was that it is a traditional air swamp cooler. They closed the windows and were getting natural exfiltration therough cracks to relieve pressure until the ehaust fan turned on.

The combination of indoor temperature and the humidity being exahusted had the same wet bulb temperature as the ambinet air as well. This constant wet bulb always is neglected when you argue the physics of evaporative cooling nick. the constant wet bulb makes it sound like it was outdoor air being cooled as well.

They were only up against an 82 ambient at night, but as numbers have shown before under a real load, humidifying recirculated air uses more water and more airflow than dierectly treating outside air with evaporative cooling

[Abby Normal]

We ran the numbers before and it shows that more airflow and water was needed when you treat the indoor air.

When you get down to micrscopic cooling loads it may be possible for it to work on recirculated air.

A recent article on evaporative cooling, used in industrial applications not home comfort. Note there is an importance of the ambinet wet bulb, a point nick does not want to acknowledge.

[nicksanspam]

Wrong.

Nick

[Abby Normal]

Take another bong hit, everytime the load call smaller and smaller until it worked. I think you even learned the term effectiveness on that one lol.

[Abby Normal]

How about a 105F db 65F wb ambient, 10,000 Btu/hr sensible gain. You can even confer with your ficticious friends down under. Pretty small load in a fairly dry place. Read up on wet bulb first.

Maintain 80F with an indooor evaporative cooler.

[nicksanspam]

20 TA=93.6'max average temp, Phoenix in May (F) 30 WO=.0045'outdoor humidity ratio 40 TI=80'indoor temp setpoint (F) 50 PWI=EXP(17.863-9621/(460+TI))'wet surface vapor pressure ("Hg) 60 WI=.012'indoor humidity ratio setpoint 70 PAI=29.921/(1+.62198/WI)'indoor air vapor pressure ("Hg) 80 EVAPRATE=.1*(PWI-PAI)'evaporation rate (lb/h-ft^2) 90 EVAPAREA=2*2*4*40'evaporation area (ft^2) 100 P=EVAPRATE*EVAPAREA'indoor water evaporation rate (lb/h) 110 RV=P/(4.5*(WI-WO))'average outdoor ventilation rate (cfm) 120 FANCAP=2*RV'reversible fan capacity (cfm) 130 EFF=.9'air-air heat exchanger effectiveness 140 TV=TA-EFF*(TA-TI)'incoming fresh air temp (F) 150 CCAP=1000*P-1.08*(TV-TI)*RV'sensible cooling capacity (Btu/h) 160 PRINT P,FANCAP,TV,CCAP

water flow fan cap fresh air cooling (lb/h) (cfm) temp (F) (Btu/h)

30.78896 1824.531 81.36 29449.03

When indoor air rises to 80 F, we might evaporate 30.78 lb/h of water into slow-moving air from a 1'x2'x4' vertical water sculpture made from 40 2'x4'

4 mm Coroplast sheets with spacers (about $80, including some 3M 4693H glue) in a folded Coroplast tank with a float valve. Sandwich the sheets together with vertical corrugations and horizontal spacers and a plastic film manifold at the bottom, with water flowing out corrugations at the top and running down both sides. Initial film coverage might improve as mineral films build, until we clean it by pumping vinegar. Harbor Freight's $5 10 watt fountain pump can do 1 gpm with a 5' head.

When the indoor RH rises to 56%, we might run Lasko's $53 2155A 2470 cfm 90W reversible fan with a cycle timer in a wall that divides the house into 2 partitions to make a bidirectional "Shurcliff lung" air-air heat exchanger. A 40'x60'x8' tall house with 1600' of 6" walls has 800 ft^3 of stud cavities. If they contain 800 pounds of unfaced fiberglass insulation with a 144 Btu/F heat capacity and lots of surface and we move 1824 ft^3 of air with 29 Btu/F through it, the heat capacity ratio is 20%, so we might get 90% effectiveness.

And walls with inflowing air might gain less heat from the outdoors...

has an equation for the dynamic metric U-value of a breathing wall, as corrected:

Ud = VRhoaCa/(e^(VRhoaCaRs)-1) W/m^2K, where

V is the air velocity in meters per second, Rhoa is air density, 1.2 kg/m^3, Ca is the air's specific heat, 1000 J/(kg-K), and Rs is the wall's static thermal resistance in m^2-K/W.

Using V = 1/3600 (1 meter per HOUR :-), and Rs = 5.7 m^2K/W (a US R32 wall), Ud = 0.058 W/m^2, like a US R98 wall. A more typical V = 10 meters per hour makes Ud = 1.7x10^-8 W/m^2K, like a US wall with an R-value of 334 million :-)

Nick

[Andrew Barss]

: A properly designed swamp cooler system can run with : just the fan and no water, no need for extra ceiling fans.

If you're running it with a fan and no water, it's a ... fan. Swamp cooling relies on the fact that water evaporation cools nearby air. You pull outside air into the wet medium, and pump the cooler and more humid air through the house. It then exits the house through open windows (to the poster who recommended closing all the windows, that's going to completely undermine the whole thing).

-- Andy Barss

[Rod Speed]

Andrew Barss wrote

Duh.

Duh.

Duh. Pity that post was clearly suggesting ceiling fans IN ADDITION TO A SWAMP COOLER.

He's too stupid to be able to work that out for himself.