Evaporative cooler question

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snipped-for-privacy@ece.villanova.edu wrote:

Use a word three times and it is yours.

So there is no vapour barrier beneath the slab? You are wetting the soil. Or the watering system is between the slab and the insulation? It is a suspended slab now.

Yes, those people who sucessfully cool there homes.

You are assuming that you will get the conditions. Research Willis Carriers work on how to get there. The slab then adds humidity without sensible heat removal? Evaporation heat will come from the slab. Then your ceiling fans blow hot air down to the slab to cool off?
Model how it happens, don't assume setting the a dehumidistat to turn on an exhaust fan is going to do this. Indoor conditons will be well out of the comfort zone as you travel from point A to point B.

My parents in Canada have an old house. No vapour barrier under the slab, so moisture comes in. Happens in winter as well. Also the baement walls lose heat as well. Basement will be cool in Canada or PA as they are in contact with cool wet soil. What's the point out in the desert?
You can circulate air and cool house to an extent in Canada or PA by pulling cool basement air in and blowing it upstairs, or you can just hang out in the basement. Lets try it in Arizona and Vegas, different story.
Start by doubling the volume of the house in your model then to account for the basement.
And add solar and internal gains, tired of this artifically low load.

You need to give up and say "Constant Wet BulB Temperature" three more times.

I think you should stick with the Rocky Horror Picture show. "Don't dream it, Be it" , and see how comfortable you will feel.

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No. Plastic film on the ground, under stone, under concrete.

No.
Over the film and under the stone. Or maybe just a soaker hose on top.

No.

By design...

Evaporation cools the slab enough to keep the house 80 F all day.

Evaporation is exothermic? :-)

Ceiling fans as needed to keep the house air 80 F.

I've done so. Where is your numerical model?

What's wrong with that? What do you mean by "this"?

Why would you say that? Where are points A and B in this case?

More efficient house cooling using a slab on-grade in the desert.
Let's try logic again. Would you agree that:
1. 80 F with w = 0.012 is comfortable. 2. At 80 F and 100% RH, Pw = 1.033 "Hg. 3. At Wc = 0.012, Pa = 0.566 "Hg. 4. P = 0.1A(Pw-Pa) lb/h will evaporate from an A ft^2 wet surface. 5. Evaporating P lb/h of water indoors makes about 1000P Btu/h of cooling. 6. Removing it takes C cfm of exhaust air, where P = 60C0.075(Wc-Wa)=0.0367C. 7. Cooling the house and C cfm from Ta (F) to 80 F makes 1000P=(Ta-80)(98+C). 8. We can store 34K Btu of coolth in a 10K Btu/F slab with a 3.4 F temp swing.
Do you disagree with any of these statements? Which ones?
What's the conclusion?
Nick
(1) Every idea of mine, that cannot be expressed as a syllogism, is really ridiculous. (2) None of my ideas about bath-buns are worth writing down. (3) No idea of mine, that fails to come true, can be expressed as a syllogism. (4) I never have any really ridiculous idea, that I do not at once refer to my solicitor. (5) My dreams are all about bath-buns. (6) I never refer any idea of mine to my solicitor, unless it is worth writing down.
Using these letters: A is able to be expressed as a syllogism          R is really ridiculous          B is about bath-buns          C comes true          S is referred to solicitor          D is a dream          W is worth writing down, we have
1. ~A-->R (~ means "not") From _The Complete works of Lewis Carroll_, 2. B-->~W Random House/Modern Library, page 1256. 3. A-->C 4. R-->S 5. D-->B 6. S-->W.
Since D and C are the only unpaired terms above, the conclusion involves them. Starting with D in equation 5,
D-->B-->~W-->~S-->~R-->A-->C, i.e., "All my dreams come true" :-)
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snipped-for-privacy@ece.villanova.edu wrote:

Well you can explain how you are soaking a slab from below. It sounds pretty hard unless you have a suspensed slab. Soaking it from above is dangerous, impractical and unhealthy. Water on a slab will cool the slab which will eventually cool the air. You will be outside the comfort zone.

A design that says this is my final condition.

It would be endothermic, as in it would draw its heat from the slab.

I have modelled evaporative cooling many times. You have not.

Similar calculations can show that a cooling and dehumidification process can be called 'impossible processes', meaning that a cooling coil alone can not take a set of entering db/wb temperatures and produce a certain set of leaving db/wb conditions. Theoretically by taking the change in enthalpy you can calculate so much cooling is required. However, the apparatus dewpoint is sometimes 'out of reach' so to speak and the only way to produce this air is to overcool it to the desired dewpoint, then reheat it. It means you need more cooling than you can theoretically calculate because of the pyschrometric processes involved.
Evaporative cooling, where no real heat is added to the air, has to follow a constant wet bulb line, which you should be aware, are virtually parallel to the enthalpy lines.
Your model does not do this and is flawed. 80F @ 54% RH is not possible by evaporating water alone. Evaporative cooling will produce dryer air at 80F. You have not allowed for any internal latent gains, so why the rise in wet bulb temperature?
In the box all the changes take place. Your box is the room, so the occupants of the box experience all the swings.
I gave you two scenarios where air is over humidified to cool it down to 71 then the limited sensible heat allowed for in your calcs warms it to 80F @ 54%, as well as allowing the space to overheat then evaporating water to cool it back down to 80 @ 54%.
But just picking a point and setting the dehumidistat is not going to maintain those conditions.

You are evaporating water off of a slab. This will cool off the slab, then you are blowing hot air down from the ceiling to transfer heat from the air to the slab.

You are not following a constant wet bulb. Your indoor dry bulb temperature will not be constant.

Efficient housing will reduce the load, not lower the CFM per unit cooling.

It has a dewpoint of 61.8F, higher than the 60F recommended by ASHRAE. Currently, it looks like a of 57F seems desirable. If you read my post about what it was like in the tropics with no power for a month after a hurricane, I would have enjoyed 80F @ 54% RH, after several weeks of 86F @ 85% RH.

At 80F the vapour pressure of saturated water is about 0.5073 psia, it would require about 1048.3 Btu/lbm to evaporate.

at 80F and 54% RH, the vapour pressure of water int the air would be about .5703 x .54= .3080 psia

Can't confirm or deny that one right now, lost even my Dectron book, but it does sound like an evaporation rate. Heat coming from the water itself. The cool water will draw heat from the slab. Just like the 'boy scout trick'.

1048.3 Btu is the heat required to evaporate a pound of water. By using a wet cell media, it can directly convert sensible heat in air to latent heat to provide apparent sensible cooling, or you can cool off a slab, then blow HOT stratified air down from the ceiling all day until the room and slab temps equalize.
How about this, what reads a cooler temperature, the wet bulb on a sling psychrometer that you whirl around or one the wet bulb on a sling that you do not whirl?

60 converts minutes to hours, 0.075 is a standard air density. Multiply the product of the two by the CFM and the difference in specific humidity and it will give pounds per hour of moisture exhausted. However without allowing for internal latent gains, or allowing the room temp to vary from 80, you will never see 0.012.

You are cooling a slab by evaporating water, then you are blowing hot (as in hotter than 80F) air at this slab until the slab and room air are at the same temperature. The room air will get hotter than 80, the slab cooler, after it all dries up, the slab and room air will eventually be the same temperature after a while.
So you may average an 80 F indoor temperature as well, but you will not have a constant 80F indoor temperature. You will be outside the comfort zone.
You would have better luck with the Inverted Pool of Pine.

I will take your word on the thermal capacitance of concrete, but when you rely on this then you really need to look at all the heat built up from the sun beating on the roof, walls and ground all day.

You have not been able to re-invent the wheel this time. You need the box, put it on the roof or indoors, condition the outside air prior to it entering the space and real maintain comfort, not something that averages out as being frugally comfortable. If you make the room the box, you cannot maintain comfort.
How about make the house a swimming pool and have a swim up kitchen table. :-)
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I disagree, in a Las Vegas climate.

Some by radiation, but cool air falls, so we'll get a lot more coolth out of the slab by turning on ceiling fans as needed.

The ASHRAE-55 2004 standard says 80 F with w = 0.012 is comfortable.
It also requires exhaust air control.

Impossible. The water turns on at 80 F. The exhaust fan turns on at 54% RH.

I don't understand that question, but "internal latent gains" would be small compared to the deliberate indoor evaporation, so I don't think that further complication will change the picture much.

What swings? The water turns on at 80 F. The exhaust fan turns on at 54% RH. The slab would get down to 75.5 F at night, which is still comfortable, but with no ceiling fans, the air can be warmer.

Time to call the psychrometric police? :-)

It will be as constant as the thermostat dead band and hysteresis allow.

The new ASHRAE-55 2004 standard says that is max temp and RH corner of the comfort zone, ie it is "comfortable."

Gee, we agree on something :-)

I get 14.696/(1+0.62198/0.012) = 0.2782 psia (0.566 "Hg.) Perhaps we need to consult Paul of the pulsating rectum.

Good. You might find an older ASHRAE HOF for $25 on ebay.

Close enough.

Bowen (1926) would say the same temp, eventually.
6. Removing it takes C cfm of exhaust air, where P = 60C0.075(Wc-Wa)=0.0367C.

Good.
Why on earth would you say that???
7. Cooling the house and C cfm from Ta (F) to 80 F makes 1000P=(Ta-80)(98+C).

Close.
I disagree (as do 21,000 surveyed for ASHRAE-55 2004 :-)
8. We can store 34K Btu of coolth in a 10K Btu/F slab with a 3.4 F

Good.
I disagree, altho this isn't the wheel :-)
Nick
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snipped-for-privacy@ece.villanova.edu wrote:

Maybe read through the Humidity Control Design guide.

You keep reckoning this Slingblade, prove it.

Maybe if some one called the cops on you, you would eventually learn what you are not grasping here. Are you an environmental or an electrical engineer?

All I have to go by is a saturated steam table and a concept that perhaps relative humidity can be expressed as the ratio of the vapour pressure of water vapour in the air at a given air temperature to the vapour pressure of water saturated at the same temperature. I am basing it on 54% and you are using 0.012 but there should not be a 10% error.

Waiting for a new one, old ones are 'dated'. In particular when everyone designing cooling and humidity control only looked at design dry bulbs with coincidental wet bulbs.

The two bulbs would eventual dry out and be the same temp.
Eventually the house with your wet floor MAY reach 80 and 54%RH. Its just that in doing so its humidity levels and temperatures will take a little trip outside the 'comfort zone' to do so.

You need the pyschrometric police to arrest you, and sentence you to a semester of the processes behind evaporative cooling.
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Nick
Something to relieve your stress, go knock yourself out
Here is a guy living the life you are dreaming of
http://www.dslab.com/interface/common/assetbrowser/assetlistview.asp?RefreshCache=True&navcon_id 96&rnd=7.041568E-02&rnd=0.3501093
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snipped-for-privacy@ece.villanova.edu wrote:

Nick
DECTRON worked out evaporation rates based on a swimming pool surface area, along with the wetted perimeter around the pool. The wet pool deck maybe a 6 foot band around the perimeter of the pool.
Evaporation is the greatest heat loss of a swimming pool. The heat to evaporate this water, comes from the water itself, not from the air in the natatorium. A pool of standing water will mainly cool itself off as it evaporates.
I am a Canadian who has been working down in the Caribbean for over six years now. I mentioned a flood in my office that took out my library. This flood was the 10 foot storm surge from Hurricane Ivan.
Believe it or not, I have tried many of your 'frugal' schemes to try and keep cool out of necessity. I found that they gave some relief to extreme conditions, but it was far from comfortable.
I had no electrical power for over a month after the hurricane and it took me 12 days to get a generator flown in. The Caribbean is not an arid environment and a typical AC design scenario, was 91F db/ 82F wb.
These design scenarios corresponded with the times I had no power. Not a condusive envirnoment to evaporative cooling but it should have been possible to get some relief.
Approximatley one week after this Category 5 storm passed we had an intermittent city water on for a couple hours each morning and each evening.
I would fill both bathtubs, and all sinks with water. I would let the water in the bathtubs stand all day so as to evaporate and cool off.
I would open the windows at night when the ambient temperatue dropped to help dissipate the heat gain from the day. From the sun beating down on the concrete home all day long as and to a minor effect from the outdoor temperature. So when you talk thermal storage, it is storing unwanted heat.
About as high mass as you can get without adding a concrete roof. All exterior walls, reinforced concrete blocks with the cores filled with rebar and concrete. Partion walls concerete block. Poured concrete floor slabs on ground floor and second floor, even poured concrete stairs to second floor. Roof was insulated with R19 AND my roof tiles were WHITE !
The indoor condition of my home ended up stabalizing at about 86F and 85%RH. The only real relief was laying in the bathtub, which cooled itself down to maybe 82 degrees. I could lay down and cool off my body mass so I could sleep. If I awoke at 3AM sweltering, I could go lay in the same tub for 20 minutes and then go back to sleep.
After I had the generator, I was able to run ceiling fans and oscillating floor fans. Blowing that warm stratified air down on us was better than nothing at all however it was not what I would call a comfort condition.
At night I would even run the clothes dryer on air fluff and some exhaust fans to pull in some cooler outdoor air, but the home pretty much stabalized at 86F. We generated internal heat from our metabolism, from our lights, and from the appliances we ran. This worked on top of the thermal storage, that gave us heat after the sun went down.
I finally managed to salvage a small 5000 btu/hr window shaker from a job site construction trailer destroyed by the storm, and by running it steady, and using a floor fan to pull cool air out of the front room to blow it into the ground floor central living area and then running my air handler I was able to get the house to stabalize at 83F and about 68% RH. Still not comfortable unless sitting below a ceiling fan, but after sweltering for weeks it was great. Perhaps the house would have been even cooler if it were not for the fan heat added to the air but it was a trade off just to circulate air to give the window shaker as much opportunity as possible to dehumidify and to reduce the stratification upstairs.
You can impractically try and model alternate cooling methods, but living under the conditions they provide is another story.
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you guys ever here of an air conditioner?
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Sure they have. The arguement is about the swamp cooler and if it can be made more efficient. Have you ever used one of them? A lot cheaper than the refrigeration and allows you to leave your windows open. Efficiency drops off rapidly with humidity above 30%.

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Not a great place for evaporative cooling :-)

Yuck.
It mighta worked better in one room, with the air handler off. But then you have to live in one room...
Adaptation is important in the Carribean. Foreigners take off most of their clothing on sailboats. BVI people start wearing sweaters when the air temp drops to 85 F. And they are thinner, with a larger heat- losing body surface to heat-generating body volume. And they march to slower drummers, with less stress, and "island time."
After a week with no electricity, my friend with a vacation home on Nevis went to the generating station to see what the problem was. The chief said "Da generator is broke. We need a new part from da mainland, but da crew dey all dronk, so we can't go in the boat today." :-)
Then again, there's lots of sun. A house with lots of insulation and a solar LiCl still on the roof might keep its air cool and dry with the windows closed all day, with an open hatchway into the still, which absorbs water vapor from indoor evaporation at night. The house needs enough thermal mass to ride through the day while the sun concentrates the LiCl solution.
NREL says San Juan is 82.7 F in August, with an 88.7 average daily max and 1890 Btu/ft^2/day of sun on the ground and w = 0.0179. How many square feet of LiCl still would we need to make that 1200 ft^2 house with 128 Btu/h-F of conductance 80 F with w = 0.012 all day?
Nick
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About 14.5 ft^2, based on some crude assumptions:
1) The LiCl still operates at a constant temp for 12 hours per day. 2) The solar energy that enters the R1 glazing with 90% transmission equals the sensible and latent heat energy needed for concentration. 3) The solution cools to 25 C at night. 4) The solution gains heat like an ASHRAE pool loses heat.
I'm not sure about 4). Suggestions welcome. The next step might be a simple TMY2 simulation.
10 A1.7409'LiCl vapor pressure constants from Hawlader (1993) 20 A2=-.065536 30 A3=-8.2416E-04 40 B1=-4675.4 50 B2=+29.31 60 B3=+.66911 70 C172690! 80 C2=-1689.8 90 C3=-187.1 100 TA.7'average ambient August temperature in San Juan (F) 110 SG90'average August sun on ground in San Juan (Btu/ft^2-day) 120 H'distillation day length (hours) 130 W=.0179'average ambient August humidity ratio in San Juan 140 PV%.4*29.921/(1+.62198/W)'ambient vapor pressure (mmHg) 150 P=9'dehumidification load (lb H2O/day) 160 TC'solution temp (C) 170 TK'3.1+TC'solution temp (K) 180 C+B1/TK+C1/TK^2-LOG(PV)/LOG(10) 190 B+B2/TK+C2/TK^2 200 A+B3/TK+C3/TK^2 210 CONC=(-B-SQR(B^2-4*A*C)/(2*A))'equilibrium soln conc (wt%) 220 TF=1.8*TC+32'solution temp (F) 230 CONCSURF00*P/(.9*SG-H*(TF-TA))'LiCl surf needed for conc (ft^2) 240 TK)8.1'solution temp (25 C) 250 AP+A2*CONC+A3*CONC^2 260 BP+B2*CONC+B3*CONC^2 270 CP+C2*CONC+C3*CONC^2 280 PVC^(AP+BP/TK+CP/(TK^2))'vapor pressure at 25 C (mmHg) 290 PVI).921/(1+.62198/.012)'indoor vapor pressure ("Hg) 300 PVL=PVC/25.4'LiCl vapor pressure ("Hg) 310 DRYRATE=.1*(PVI-PVL)'lb/h/ft^2 H2O (like an ASHRAE pool) 320 DRYSURF=P/(12*DRYRATE)'LiCl surface needed to dry P lb H2O in 12 h (ft^2) 330 PRINT TC,CONC,PVC,DRYSURF,CONCSURF
Still Solution Soln vapor Soln surface needed for temp (c) conc (%) press (mmHg) conc (ft^2) abs (ft^2)
80 52.17768 1.271565 14.52688 14.57726
Nick
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snipped-for-privacy@ece.villanova.edu wrote:

The front room would be about 80F 50% each morning,if I did not circulate the air. The front room has been my office since the storm, as the real office is a write off. Had to occupy the entire place, had taken in a few homeless souls.

I am totally acclimatized. Locals are freezing below 80F. Sweaters and jeans on in the 70's. Sun is powerful.

soon come mon

A lot of sun for 12 hours a day

Just need to recruit some people who know something about adsorbers.

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The ASHRAE 55-2004 comfort standard (based on worldwide surveys of 21,000 people) defines the winter and summer comfort zones below with equal air and wall temperatures, equal human activity levels, and a fixed 0.1 m/s air velocity:
T (F) RH clo PMV PPD
67.3 86 1 -.4778556 9.769089 75.0 66 1 .4732535 9.676994 78.3 15 1 .5239881 10.74283 70.2 20 1 -.4779105 9.770202
74.5 67 .5 -.4747404 9.706658 80.2 56 .5 .5145492 10.53611 82.2 13 .5 .5003051 10.23146 76.5 16 .5 -.4883473 9.982468
The winter zone assumes heavier clothing with more thermal resistance (clo=1), and the summer zone assumes lighter clothing (clo=0.5). The zones are defined by a +/- 0.5 score on a "Predicted Mean Vote" comfort scale that varies from -3 (very cold) to +3 (very warm.) The 4 corners of each zone are based on high and low temperatures and humidities. The "Percentage of People Dissatisfied" (PPD) score is based on the PMV. Even with PMV = 0 ("comfortable"), about 6% of the people are dissatisfied...
If people are willing to change clothing more than twice a year (early PA farmers had one set of clothes for work and another for church, and washed them twice a year, when they also took baths :-) and we vary air velocity with a ceiling fan, these zones can be expanded, which can make a solar house or one heated and cooled with the help of a whole-house fan more efficient. We can also raise the upper comfort temperature limit in air with lower humidity, and vice versa. The ASHRAE 55-2004 standard contains a BASIC program to help do this. Here are some calculations based on NREL's long-term December and August weather averages for San Diego:
20 CLO = 1'clothing insulation (clo) 30 MET=1.1'metabolic rate (met) 40 WME=0'external work (met) 50 TA.6'air temp (C) 60 TR.6'mean radiant temp (C) 70 VEL=.1'air velocity 80 RH=0'relative humidity (%) 90 DATA 68.8,0.0062,0.05,1 100 DATA 83.9,0.0062,0.5,0.5 110 DATA 67.1,0.0121,0.05,1 120 DATA 82.9,0.0121,0.5,0.5 130 FOR CASE = 1 TO 4 140 READ TC,WA,VEL,CLO 145 TA=(TC-32)/1.8'air temp (C) 146 TR=TA'mean radiant temp (C) 150 PA).921*3377.2/(1+.62198/WA)'water vapor pressure (Pa) 160 DEF FNPS(T)=EXP(16.6536-4030.183/(TA+235))'sat vapor pressure, kPa 170 IF PA=0 THEN PA=RH*10*FNPS(TA)'water vapor pressure, Pa 180 ICL=.155*CLO'clothing resistance (m^2K/W) 190 M=MET*58.15'metabolic rate (W/m^2) 200 W=WME*58.15'external work in (W/m^2) 210 MW=M-W'internal heat production 220 IF ICL<.078 THEN FCL=1+1.29*ICL ELSE FCL=1.05+.645*ICL'clothing factor 230 HCF.1*SQR(VEL)'forced convection conductance 240 TAA=TA+273'air temp (K) 250 TRA=TR+273'mean radiant temp (K) 260 TCLA=TAA+(35.5-TA)/(3.5*(6.45*ICL+.1))'est clothing temp 270 P1=ICL*FCL:P2=P1*3.96:P3=P1*100:P4=P1*TAA'intermediate values 280 P508.7-.028*MW+P2*(TRA/100)^4 290 XN=TCLA/100 300 XF=XN 310 N=0'number of iterations 320 EPS=.00015'stop iteration when met 330 XF=(XF+XN)/2'natural convection conductance 340 HCN=2.38*ABS(100*XF-TAA)^.25 350 IF HCF>HCN THEN HC=HCF ELSE HC=HCN 360 XN=(P5+P4*HC-P2*XF^4)/(100+P3*HC) 370 N=N+1 380 IF N>150 GOTO 500 390 IF ABS(XN-XF)>EPS GOTO 330 400 TCL0*XN-273'clothing surface temp (C) 410 HL1=.00305*(5733-6.99*MW-PA)'heat loss diff through skin 420 IF MW>58.15 THEN HL2=.42*(MW-58.15) ELSE HL2=0'heat loss by sweating 430 HL3=.000017*M*(5867-PA)'latent respiration heat loss 440 HL4=.0014*M*(34-TA)'dry respiration heat loss 450 HL5=3.96*FCL*(XN^4-(TRA/100)^4)'heat loss by radiation 460 HL6L*HC*(TCL-TA)'heat loss by convection 470 TS=.303*EXP(-.036*M)+.028'thermal sensation transfer coefficient 480 PMV=TS*(MW-HL1-HL2-HL3-HL4-HL5-HL6)'predicted mean vote 490 GOTO 510 500 PMV999!:PPD0 510 PRINT TC,WA,VEL,CLO,PMV 520 NEXT CASE
Dry bulb Humidity Air vel. Clothing Predicted mean temp (F) ratio (m/s) (Clo) vote (PMV)
68.8 .0062 .05 1 -.4997552 83.9 .0062 .5 .5 .4852427 67.1 .0121 .05 1 -.491671 82.9 .0121 .5 .5 .4890098
NREL says average daily highs and lows are 48.8 and 66.1 F with w = 0.0062 pounds of water per pound of dry air in December and 67.3 and 77.8 with w = 0.0121 in August. An airtight well-insulated house with thermal mass and internal heat gain and a smart whole-house fan controller would barely need heating or cooling all year. Architects call this "thermal sailing."
With inexpensive solar heating and whole-house fan heating and cooling, it would be more efficient to make the house air temperature closer to the upper comfort limit on an average winter day and closer to the lower comfort limit on an average summer day, in order to store lots of thermal energy in the mass of a house. A mean radiant (wall) temp that's less than the house air temp in winter and greater in summer would allow raising the upper winter air comfort temp limit and lowering the lower summer air comfort temp limit. Occupants might also vary activity levels and wear clothing with more or less resistance, eg a sweater as well as a long- sleeve shirt in wintertime.
Nick
Innova AirTech Instruments has an excellent comfort web site:
http://www.impind.de.unifi.it/Impind/didattica/materiale/microclima/innova/thermal.htm
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and were still smelling pretty good by June. However, they were starting to smell, so brides carried a bouquet of flowers to hide the smell.
Baths equaled a big tub filled with hot water. The man of the house had the privilege of the nice clean water, then all the other sons and men, then the women and finally the children. Last of all the babies. By then the water was so dirty you could actually loose someone in it. Hence the saying, "Don't throw the baby out with the bath water".
Houses had thatched roofs. Thick straw piled high, with no wood underneath. It was the only place for animals to get warm, so all the pets... dogs, cats, and other small animals, mice, rats, bugs lived in the roof. When it rained it became slippery and sometimes the animals would slip and fall off the roof. Hence the saying, "It's raining cats and dogs,"
There was nothing to stop things from falling into the house. This posed a real problem in the bedroom where bugs and other droppings could really mess up your nice clean bed. So, they found if they made beds with big posts and hung a sheet over the top, it addressed that problem. Hence those beautiful big 4 poster beds with canopies.
The floor was dirt. Only the wealthy had something other than dirt, hence, the saying "dirt poor". The wealthy had slate floors which would get slippery in the winter when wet. So they spread thresh on the floor to help keep their footing. As the winter wore on they kept adding more thresh until when you opened the door it would all start slipping outside. A piece of wood was placed at the entryway, hence a "thresh hold".
They cooked in the kitchen in a big kettle that always hung over the fire. Every day they lit the fire and added things to the pot. They mostly ate vegetables and didn't get much meat. They would eat the stew for dinner leaving leftovers in the pot to get cold overnight and then start over the next day. Sometimes the stew had food in it that had been in there for a month. Hence the rhyme: peas porridge hot, peas porridge cold, peas porridge in the pot nine days old."
Sometimes they could obtain pork and would feel really special when that happened. When company came over, they would bring out some bacon and hang it to show it off. It was a sign of wealth and that a man "could really bring home the bacon." They would cut off a little to share with guests and would all sit around and "chew the fat."
Those with money had plates made of pewter. Food with a high acid content caused some of the lead to leach onto the food. This happened most often with tomatoes, so they stopped eating tomatoes... for 400 years.
Most people didn't have pewter plates, but had trenchers - a piece of wood with the middle scooped out like a bowl. Trencher were never washed and a lot of times worms got into the wood. After eating off wormy trenchers, they would get "trench mouth."
Bread was divided according to status. Workers got the burnt bottom of the loaf, the family got the middle, and guests got the top, or the "upper crust".
Lead cups were used to drink ale or whiskey. The combination would sometimes knock them out for a couple of days. Someone walking along the road would take them for dead and prepare them for burial. They were laid out on the kitchen table for a couple of days and the family would gather around and eat and drink and wait and see if they would wake up. Hence the custom of holding a "wake".
Church yards started running out of places to bury people. So, they would dig up coffins and would take their bones to a house and re-use the grave. In reopening these coffins, one out of 25 coffins were found to have scratch marks on the inside and they realized they had been burying people alive. So they thought they would tie a string on their wrist and lead it through the coffin and up through the ground and tie it to a bell. Someone would have to sit out in the graveyard all night to listen for the bell. Hence on the "graveyard shift" they would know that someone was "saved by the bell" or he was a "dead ringer".
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They probably used soap and water and washcloths more often...

Wordorigins.org: Etymologies & Word Origins:
Dirt Poor
This term is US in origin and dates to 1937. The exact reference is uncertain, but it is most likely to be evocative of the dust bowl and the extreme poverty and unclean conditions in which many had to live during the Depression.
The bit of internet lore about Life in the 1500s claims that it dates to Shakespearian England where finished floors were rare. This is utterly false.

The Mavens' Word of the Day May 15, 2001
Sylvia Chrost wrote:
I'm interested in the etymology of the phrase dead ringer. I heard that its origins are tied to being buried alive and the idea of a doppelgnger or double.
A doppelgnger is 'a ghostly double or counterpart of a living person'; in German it means 'double goer'. This spiritual being inhabits the works of German romantic writers, and is typically used to symbolize a character's internal conflict. It's also a literary device used in the horror fiction of English language authors such as Oscar Wilde, Edgar Allan Poe, and Bram Stoker. A doppelgnger is usually sinister and exists to haunt the living person. An encounter with one's spiritual double may mean imminent death, and if the double is attacked, the living person will soon die or commit suicide.
Fear of being buried alive is also a common literary theme in 18th- and 19th-century literature, first in Germany, and then in France, Britain, and elsewhere. (Poe's "The Black Cat" and "The Fall of the House of Usher" are American examples.) This fear was not unfounded. Until the 20th century, medical signs and criteria of physical death were unreliable, and there are real cases of people being buried prematurely. A widely circulated but untrue explanation of the term dead ringer is connected to the practice of tying a rope to the wrist of a buried person, the rope being attached to a bell outside the coffin. If the person was indeed buried alive, the bell could be used to signal for help. (If you want the lugubrious and humorous details about this part of our social history, read Buried Alive: The Terrifying History of Our Most Primal Fear, by Dr. Jan Bondeson.)
Outside of literature, the term doppelgnger is sometimes used to mean 'a (living or dead) person who closely resembles someone else'. The term dead ringer has the same meaning, but it's not a literary term. For example, maybe your boyfriend is a "dead ringer" for Brad Pitt.
In this use, the adjective dead means 'perfect, absolute, exact, utmost', in reference to death being the final step in life. Without the adjective "dead," the noun ringer just means 'a double or counterpart'. So dead ringer means 'exact double'.
But ringer has other pejorative meanings dating from the late 1800s. The basic sense is 'an impostor or deceptive substitute unfairly entered into a contest or competition'. It can refer to a superior horse entered in a race to substitute for a slower horse, usually under an alias and with its appearance altered to resemble the inferior horse. Or a ringer could be an inferior horse substituted for a superior one that has been sold. Also in sports, a ringer is a professional athlete deceptively substituted for an amateur. In gambling games, a ringer is a marked or specially ordered deck of cards, a loaded or otherwise modified pair of dice, a dishonest dealer, or an expert card player posing as a novice. A counterfeit gem or coin can be called a ringer. Other related meanings include: 'an outsider; uninvited guest; intruder'.
The noun ringer comes from the verb ring (in), in the early 1800s meaning 'to falsify, disguise, or alter' or 'to introduce fraudulently; substitute one person/thing for another'. In this use it's sometimes spelled "wring (in)." Ring (in) can also mean 'to join with others, usually in an intrusive way'. These uses of ring (in) are probably connected to the meaning 'to announce by ringing a bell'. According to the Barnhart Dictionary of Etymology, there is also a probable association with the slang expression ring the changes 'to substitute counterfeit money in various ways', a pun on the the standard sense 'to go through all the variations in ringing a peal of bells'. As an alternative origin for ringer, Thomas L. Clark's The Dictionary of Gambling and Gaming says it was originally a finger ring with a small flange used for palming cards.
Carol
Copyright 1995-2005 Random House, Inc. All rights reserved.
Questions & Answers: Saved by the bell
[Q] From a lot of people - including Mike Whitling and Lisa Smith from the USA and Barrie J Wright from Australia:
"The following is part of a longer piece that's been making the rounds by e-mail in recent months. Is any of it true? England is old and small and they started running out of places to bury people. So, they would dig up coffins and would take their bones to a house and re-use the grave. In reopening these coffins, one out of 25 coffins were found to have scratch marks on the inside and they realized they had been burying people alive. So they thought they would tie a string on their wrist and lead it through the coffin and up through the ground and tie it to a bell. Someone would have to sit out in the graveyard all night to listen for the bell. Hence on the 'graveyard shift' they would know that someone was 'saved by the bell', or he was a 'dead ringer'."
[A] You may not be pleased to hear that all this is complete and utter hogwash, just like the rest of the article. It's an example of a fascinating process (that is, from a sociolinguistic perspective) in which people actively seek out stories to explain phrases, not really caring whether they are true, just that they are psychologically satisfying. As a result, they are powerful memes, strongly resisting refutation. But World Wide Words is renowned as the home of lost causes, so I'll give it a go.Saved by the bell is actually boxing slang, dating from the 1930s. A contestant being counted out might be saved by the ringing of the bell for the end of the round, giving him a minute to recover. Graveyard shift is an evocative term for the night shift between about midnight and eight in the morning, when-no matter how often you've worked it-your skin is clammy, there's sand behind your eyeballs, and the world is creepily silent, like the graveyard (sailors similarly know the graveyard watch, the midnight to four a.m. stint). The phrase dates only from the early years of the twentieth century. The third phrase-dead ringer-dates from roughly the same period or perhaps a decade or two earlier. I've written about it previously, so won't explain it again.So none of these expressions has anything to do with the burying of bodies.
World Wide Words is copyright Michael Quinion, 1996-2005.
http://historymedren.about.com/library/weekly/aa042202a.htm
debunks the full hoax.
Nick
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Not much. The main requirement is dehumidification. With humid outdoor air, airtightness is important.

About 14.5, to distill and then absorb 9 pounds of water in 24 hours.

I think this is reasonably simple, with no vacuum. Within your reach as a tinkerer. Of course you'd want to translate all this into wetbulbese first :-) One complication is that the LiCl solution will warm at night with 9x1000/12h = 750 Btu/h as it absorbs water vapor, and warming it raises the vapor pressure, so it won't absorb water vapor as rapidly, and the moist air from the house (12hx60xcfm(0.012-0.001) makes about 15 cfm) would be returned warmer.
So, the still needs to be larger (8'x8' would work) or cooled at night. The LiCl solution also needs to be stirred at night (with a plastic fountain pump) to avoid making a low-concentration layer on top that reduces the rate of water vapor absorption. Another pump might move cool water from a small roofpond (eg on top of the still glazing) through some plastic tubes in the solution.
Nick
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snipped-for-privacy@ece.villanova.edu wrote:

My hometown in Canada had a yearly average temperature of about 32F. Here the yearly average is 80.
Being a small island, for 6 months out of the year the dewpoint is very close to the sea water temperature, so it hovers around 80. A summer night it may cool off to about 84F on average with the same dewpoint.
Outdoor temperature does not have much of an impact on the cooling load, it is basically dependent on how sunny it is.
A problem is when there are tropical storms and hurricanes. The eye of such storms can be 200 miles away however we would experience heavy rains. This would drop the outdoor temperature down to 81 or 80 say, however the dewpoint is still right around 80.
Another problem, more so on office buildings, but also applies to larger high end homes is that there is often a lot of glazing , in particular facing south.
The low december sun, seems to maximize solar gain in December through this glazing. Up North, this reduces the heating load, but down here it increases the sensible gain in the space.
The loads here peak in September, due to the heavier ventialtion load, humidity and then dry bulb temperature, in that order. In December the ventilation load is reduced as air has cooled and the dewpoint is dropped to the mid 70s, but the solar gain is greater. Over all the load has dropped in December , but more cool air has to be delivered to the space.
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snipped-for-privacy@ece.villanova.edu wrote:

Now if it typically dropped down below 80 at night in Vegas, you would not even have to use evaporative cooling, except to maybe keep humidity up. Just shut off the pump in the 'box on the roof' until humidity fell below 40% inside.
You would only be dealing with the internal load and the heat discharging from the thermal flywheel :) Maybe you would only have to open the windows at night.
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