DIYbanter

DIYbanter (https://www.diybanter.com/)
-   Home Repair (https://www.diybanter.com/home-repair/)
-   -   dry environment and air conditioning (https://www.diybanter.com/home-repair/113559-dry-environment-air-conditioning.html)

Montenegro July 14th 05 12:11 AM

dry environment and air conditioning
 
With the heat wave I have been using air conditioning for three days in a
row (central air). The relative humidity is now at 35% (too dry!!)and I am
wondering if I should use a humidifier? The outside temperature is 41
celcius here in Southern Ontario.

Thanks for any advise!

M.



[email protected] July 14th 05 01:03 AM

I seem to remember 50% relative humidity as a standard.
What about pans of water.
I grew up in a Wisconsin house with radiators.
filling specially constructed pans on top of the radiators was daily
chore.
TB


Joseph Meehan July 14th 05 01:25 AM

Montenegro wrote:
With the heat wave I have been using air conditioning for three days
in a row (central air). The relative humidity is now at 35% (too
dry!!)and I am wondering if I should use a humidifier? The outside
temperature is 41 celcius here in Southern Ontario.

Thanks for any advise!

M.


The problem is most humidifiers I have seen use some form of heat to
help increase the humidity. You don't what that. What you may want is
something like a swamp cooler that is often used in very dry areas. Somehow
I doubt if that would be a great idea in the long run however.

--
Joseph Meehan

Dia duit



Dr. Hardcrab July 14th 05 02:23 AM


"Joseph Meehan" wrote in message
...
Montenegro wrote:
With the heat wave I have been using air conditioning for three days
in a row (central air). The relative humidity is now at 35% (too
dry!!)and I am wondering if I should use a humidifier? The outside
temperature is 41 celcius here in Southern Ontario.

Thanks for any advise!

M.


The problem is most humidifiers I have seen use some form of heat to
help increase the humidity. You don't what that. What you may want is
something like a swamp cooler that is often used in very dry areas.
Somehow I doubt if that would be a great idea in the long run however.


Agreed. Maybe he can raise his thermostat? Hey! 80 degrees at 35% humidity
ought to be pretty comfortable.....



[email protected] July 14th 05 11:44 AM

Dr. Hardcrab wrote:

"Joseph Meehan" wrote:


Montenegro wrote:


With the heat wave I have been using air conditioning for three days
in a row (central air). The relative humidity is now at 35% (too
dry!!)...


Congratulations. You must have one of those fairly airtight Canadian houses.

The problem is most humidifiers I have seen use some form of heat to
help increase the humidity. You don't what that. What you may want is
something like a swamp cooler that is often used in very dry areas.


A portable swamp cooler would work, or increasing the AC airflow? There
are lots of ways to increase the RH. Green plants, foutains in series
with humidistats, indoor misters, damp basement floors...

Agreed. Maybe he can raise his thermostat? Hey! 80 degrees at 35% humidity
ought to be pretty comfortable.....


The ASHRAE 55-2004 standard says 80 F at 55% would be comfortable.

Nick


Montenegro July 15th 05 12:28 AM

Very useful tips!

I am doing the 80 F at 55, and I am saving energy, sleeping better (not as
cold as before!) ana having less problems of drying skin and dry nose and
eyes.

Thanks so much to all of you

Montenegro


"Montenegro" wrote in message
.. .
With the heat wave I have been using air conditioning for three days in a
row (central air). The relative humidity is now at 35% (too dry!!)and I am
wondering if I should use a humidifier? The outside temperature is 41
celcius here in Southern Ontario.

Thanks for any advise!

M.





Tony July 15th 05 04:23 PM

On 14 Jul 2005 06:44:14 -0400, wrote:

snip

The ASHRAE 55-2004 standard says 80 F at 55% would be comfortable.

Nick


I can tell you from experience the past two weeks, that 80 degrees F
at 55%-60% humidity feels much better than 76 degrees at 80% humidity

We've been having some rather warm temps (upstate NY) and walking into
the house from outside it's incredible the difference the humidity
makes. I never ran AC in the whole house before and was amazed at the
difference it makes.

Tony




[email protected] July 15th 05 09:19 PM

Tony wrote:

The ASHRAE 55-2004 standard says 80 F at 55% would be comfortable.


I can tell you from experience the past two weeks, that 80 degrees F
at 55%-60% humidity feels much better than 76 degrees at 80% humidity


The ASHRAE 55-2004 standard says you would be more comfy at 76/80.

Nick

20 CLO = 1'clothing insulation (clo)
30 MET=1.1'metabolic rate (met)
40 WME=0'external work (met)
50 VEL=.1'air velocity
70 DEF FNPS(T)=EXP(16.6536-4030.183/(TA+235))'sat vapor pressure, kPa
80 DATA 80,57.5
90 DATA 78.707,80
100 FOR CASE = 1 TO 2
110 READ TA,RH
120 TA=(TA-32)/1.8
130 TR=TA
140 PA=RH*10*FNPS(TA)'water vapor pressure, Pa
150 ICL=.155*CLO'clothing resistance (m^2K/W)
160 M=MET*58.15'metabolic rate (W/m^2)
170 W=WME*58.15'external work in (W/m^2)
180 MW=M-W'internal heat production
190 IF ICL.078 THEN FCL=1+1.29*ICL ELSE FCL=1.05+.645*ICL'clothing factor
200 HCF=12.1*SQR(VEL)'forced convection conductance
210 TAA=TA+273'air temp (K)
220 TRA=TR+273'mean radiant temp (K)
230 TCLA=TAA+(35.5-TA)/(3.5*(6.45*ICL+.1))'est clothing temp
240 P1=ICL*FCL:P2=P1*3.96:P3=P1*100:P4=P1*TAA'intermed iate values
250 P5=308.7-.028*MW+P2*(TRA/100)^4
260 XN=TCLA/100
270 XF=XN
280 N=0'number of iterations
290 EPS=.00015'stop iteration when met
300 XF=(XF+XN)/2'natural convection conductance
310 HCN=2.38*ABS(100*XF-TAA)^.25
320 IF HCFHCN THEN HC=HCF ELSE HC=HCN
330 XN=(P5+P4*HC-P2*XF^4)/(100+P3*HC)
340 N=N+1
350 IF N150 GOTO 480
360 IF ABS(XN-XF)EPS GOTO 300
370 TCL=100*XN-273'clothing surface temp (C)
380 HL1=.00305*(5733-6.99*MW-PA)'heat loss diff through skin
390 IF MW58.15 THEN HL2=.42*(MW-58.15) ELSE HL2=0'heat loss by sweating
400 HL3=.000017*M*(5867-PA)'latent respiration heat loss
410 HL4=.0014*M*(34-TA)'dry respiration heat loss
420 HL5=3.96*FCL*(XN^4-(TRA/100)^4)'heat loss by radiation
430 HL6=FCL*HC*(TCL-TA)'heat loss by convection
440 TS=.303*EXP(-.036*M)+.028'thermal sensation transfer coefficient
450 PMV=TS*(MW-HL1-HL2-HL3-HL4-HL5-HL6)'predicted mean vote
460 PPD=100-95*EXP(-.03353*PMV^4-.2179*PMV^2)'predicted % dissatisfied
470 GOTO 490
480 PMV=99999!:PPD=100
490 PRINT TA,RH,PMV,PPD
500 NEXT CASE

Temp (C) RH PMV PPD

26.66667 57.5 1.106953 30.83258
24.44445 80 .6077689 12.74688
25.94833 80 1.106916 30.83087

Innova AirTech Instruments has an excellent comfort web site...
http://www.impind.de.unifi.it/Impind...va/thermal.htm


Tony July 18th 05 08:42 PM


No offense, but at 80% humidity, the air feels like a damp blanket
clinging to your skin.

Maybe if the wind was blowing, it would feel better.

Tony


On 15 Jul 2005 16:19:28 -0400, wrote:

Tony wrote:

The ASHRAE 55-2004 standard says 80 F at 55% would be comfortable.


I can tell you from experience the past two weeks, that 80 degrees F
at 55%-60% humidity feels much better than 76 degrees at 80% humidity


The ASHRAE 55-2004 standard says you would be more comfy at 76/80.

Nick

20 CLO = 1'clothing insulation (clo)
30 MET=1.1'metabolic rate (met)
40 WME=0'external work (met)
50 VEL=.1'air velocity
70 DEF FNPS(T)=EXP(16.6536-4030.183/(TA+235))'sat vapor pressure, kPa
80 DATA 80,57.5
90 DATA 78.707,80
100 FOR CASE = 1 TO 2
110 READ TA,RH
120 TA=(TA-32)/1.8
130 TR=TA
140 PA=RH*10*FNPS(TA)'water vapor pressure, Pa
150 ICL=.155*CLO'clothing resistance (m^2K/W)
160 M=MET*58.15'metabolic rate (W/m^2)
170 W=WME*58.15'external work in (W/m^2)
180 MW=M-W'internal heat production
190 IF ICL.078 THEN FCL=1+1.29*ICL ELSE FCL=1.05+.645*ICL'clothing factor
200 HCF=12.1*SQR(VEL)'forced convection conductance
210 TAA=TA+273'air temp (K)
220 TRA=TR+273'mean radiant temp (K)
230 TCLA=TAA+(35.5-TA)/(3.5*(6.45*ICL+.1))'est clothing temp
240 P1=ICL*FCL:P2=P1*3.96:P3=P1*100:P4=P1*TAA'intermed iate values
250 P5=308.7-.028*MW+P2*(TRA/100)^4
260 XN=TCLA/100
270 XF=XN
280 N=0'number of iterations
290 EPS=.00015'stop iteration when met
300 XF=(XF+XN)/2'natural convection conductance
310 HCN=2.38*ABS(100*XF-TAA)^.25
320 IF HCFHCN THEN HC=HCF ELSE HC=HCN
330 XN=(P5+P4*HC-P2*XF^4)/(100+P3*HC)
340 N=N+1
350 IF N150 GOTO 480
360 IF ABS(XN-XF)EPS GOTO 300
370 TCL=100*XN-273'clothing surface temp (C)
380 HL1=.00305*(5733-6.99*MW-PA)'heat loss diff through skin
390 IF MW58.15 THEN HL2=.42*(MW-58.15) ELSE HL2=0'heat loss by sweating
400 HL3=.000017*M*(5867-PA)'latent respiration heat loss
410 HL4=.0014*M*(34-TA)'dry respiration heat loss
420 HL5=3.96*FCL*(XN^4-(TRA/100)^4)'heat loss by radiation
430 HL6=FCL*HC*(TCL-TA)'heat loss by convection
440 TS=.303*EXP(-.036*M)+.028'thermal sensation transfer coefficient
450 PMV=TS*(MW-HL1-HL2-HL3-HL4-HL5-HL6)'predicted mean vote
460 PPD=100-95*EXP(-.03353*PMV^4-.2179*PMV^2)'predicted % dissatisfied
470 GOTO 490
480 PMV=99999!:PPD=100
490 PRINT TA,RH,PMV,PPD
500 NEXT CASE

Temp (C) RH PMV PPD

26.66667 57.5 1.106953 30.83258
24.44445 80 .6077689 12.74688
25.94833 80 1.106916 30.83087

Innova AirTech Instruments has an excellent comfort web site...
http://www.impind.de.unifi.it/Impind...va/thermal.htm



All times are GMT +1. The time now is 10:01 AM.

Powered by vBulletin® Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004 - 2014 DIYbanter