Home  |  Contents 
Other Stuff
  Forum Index : Other Stuff         Section
Subject Topic: habitable temperature / humidity Post ReplyPost New Topic
Author
Message << Prev Topic | Next Topic >>
chronic
Guru
Guru


Joined: 21 January 2012
Location: Australia
Online Status: Offline
Posts: 417
Posted: 12 February 2017 at 2:28am | IP Logged Quote chronic

Eastern Aus is in heatwave, more than usual.

I measured the temperature on the window ledge here (indoors)
at 50.3 degrees C the other day. A while later it cooled down
but the humidity shot up and was cited at 86%..

Granted the ledge was in sunlight but, this is residential living space...

So I wondered, what is the habitation limit wrt temperature etc, using simple electric fans and sweat to cool down ?

At a guess, I think, the max limit would be very close to the "dew point", ie , the point at which a wet surface (lungs/skin) is in equilibrium with the humid air. IE when hot humid air enters your nose/lungs, it cools to your body heat, and subsequently if it is too humid, water will condense and dump heat..cheerful isn't it.

So I found the dew point calculator on the net ... for a dew point of 38 deg C,
ie lungs. [any better figures, anyone, please speak up]

Temp @ Humidity
C %
...
40 90
42 81
44 72
46 65
48 60
50 54
...

In other words, any zones beyond that are not viable. It might seem
unlikely, but it is easy to get a combination of humid air (raining)
and a local environment that has yet to cool down. It would be interesting to see maps
of where those conditions are going to occur often and which cities.




Back to Top View chronic's Profile Search for other posts by chronic
 
Gizmo
Admin Group
Admin Group
Avatar
Administrator

Joined: 05 June 2004
Location: Australia
Online Status: Offline
Posts: 4394
Posted: 12 February 2017 at 3:22am | IP Logged Quote Gizmo

Its 41c here at the moment inside the house. In the shed ( open roller doors ) its 48c. Both thermometers are in the shade, ventilated area, thats important to get a accurate measurement. Yesterday we broke several heat records, and they expect more records to be broken today.

I believe humans can tolerate over 50c, provided we drink lots of water, dont exert ourselves and our sweat can evaporate. Thats where humidity comes into it, our sweat needs to evaporate. It also helps if we can cool down at night. Other animals can struggle with the heat, depending on where they evolved. Cats are from Africa desert regions, and can handle a bit of heat, but dogs are from northern Europe and can get into trouble during heat waves.

Comfort is another thing. I'm sitting in my little office with its little air conditioner running flat out. I'm catching up on work, and my dog is asleep on the floor. Its about 28c in here, which is OK for me. I check the power inverter ever hour or so, all up I'm pulling 1100 watts from my system, and its fan is going flat out!

Nasty weather.



__________________
"If it dont fit, use a bigger hammer."

The Back Shed
JAQ Software
Back to Top View Gizmo's Profile Search for other posts by Gizmo Visit Gizmo's Homepage
 
TassyJim
Guru
Guru


Joined: 07 August 2011
Location: Australia
Online Status: Online
Posts: 1942
Posted: 12 February 2017 at 5:30am | IP Logged Quote TassyJim

You should move to Tassie.
15.1 maximum today and currently 12.6 63% humidity

Apparent temperature was 0.9 a short time ago.

Jim



__________________
It all started with the ZX81....
VK7JH
http://www.c-com.com.au/MMedit.htm
Back to Top View TassyJim's Profile Search for other posts by TassyJim Visit TassyJim's Homepage
 
gpalterpower
Senior Member
Senior Member
Avatar

Joined: 19 July 2009
Location: Australia
Online Status: Offline
Posts: 148
Posted: 12 February 2017 at 12:09pm | IP Logged Quote gpalterpower

Yep. we copped it today too. Man it was hot.

I found myself in town today at Harvey Norman looking for a small window air conditioner. They quickly advised me that they just sold the last one that morning.

Not to be deterred I asked about portable ones.The choice of 3 were 2.5 to 3.5 kw. These were not inverter type and I knew that my off grid system probably wouldn't handle that kind of power demand so I looked at split systems. A 2.5 kw with power usage of 0.49kw. How is this possible? I understand with inverter technology the fan/compressor is not cutting in and out, but constantly changing speed, but still dosent add up.
A trip to Bunnings later in the day showed some better priced air con units. $399 for a 2.6kw unit. Usage 0.68kw. Still within my system capabilities. Is this the maximum power requirements to run this unit? I'll be back there first thing tomorrow morning if it is! Marcus

Ps. Definitely cooled down now but nowhere like Tassies temp! That sounds nice!

__________________
if it aint broke dont fix it!!
Back to Top View gpalterpower's Profile Search for other posts by gpalterpower
 
chronic
Guru
Guru


Joined: 21 January 2012
Location: Australia
Online Status: Offline
Posts: 417
Posted: 12 February 2017 at 1:30pm | IP Logged Quote chronic

Dry heat is fine. I enjoy it ! The marathon runners are the best example I guess,
as long as there is water to drink and evaporation, there is cooling.
But it is not dry heat so much.

The temperatures/humiditiy pairs above are a little optimistic, in that resting metabolism adds
80 - 100 watts to be dissipated as well. It cannot be dissipated outside the curve above.



Edited by chronic on 12 February 2017 at 1:37pm
Back to Top View chronic's Profile Search for other posts by chronic
 
gpalterpower
Senior Member
Senior Member
Avatar

Joined: 19 July 2009
Location: Australia
Online Status: Offline
Posts: 148
Posted: 12 February 2017 at 11:25pm | IP Logged Quote gpalterpower

Hi Gizmo,
Just wondering if your batteries lasted thru the night, powering your Air, or did you get that cool change in the early hours of this morn and turned it off. Was such a relief! Dragging that sort of power from them is demanding, unless you had some wind blowing up Toowoomba way. Apparently some records broken there yesterday too!

Marcus

__________________
if it aint broke dont fix it!!
Back to Top View gpalterpower's Profile Search for other posts by gpalterpower
 
joebog1
Newbie
Newbie


Joined: 07 November 2015
Location: Australia
Online Status: Online
Posts: 31
Posted: 13 February 2017 at 12:50am | IP Logged Quote joebog1

I started life as an Eng Elec.
My technology is so old that I began a new career 15 year ago as a heavy lift crane operator.
I was at Phosphate Hill ( near Mt Isa ) a few years ago and it was 44C. A crane has 4 glass sides, AND a glass roof!! ( watch that boom!!!! ) I didnt use the air con!!
( HORRIBLE things POOHH!!! ) I did drink LOTS of water! How much can a Koala bear??
I dunno, but I did move from the snowy mountains to get away from the cold, and I was born there.
Soory mods, somewhat off topic.
Joe
Back to Top View joebog1's Profile Search for other posts by joebog1
 
Gizmo
Admin Group
Admin Group
Avatar
Administrator

Joined: 05 June 2004
Location: Australia
Online Status: Offline
Posts: 4394
Posted: 13 February 2017 at 1:07am | IP Logged Quote Gizmo

gpalterpower wrote:
Hi Gizmo,
Just wondering if your batteries lasted thru the night, powering your Air, or did you get that cool change in the early hours of this morn and turned it off. Was such a relief! Dragging that sort of power from them is demanding, unless you had some wind blowing up Toowoomba way. Apparently some records broken there yesterday too!

Marcus


I've only got the air-con in the office, and its too small to cool the whole house. At night the temp drops down very quickly ( usually ), so never saw the need of installing air-con in the bedroom. Last night was a bit nasty though, was still 30c at midnight. I spent the evening in the shed working, was a bit cooler in there, and went to bed about 12:30 after a cold shower. Crap nights sleep, up at 5, bit tired.

But your right, the batteries would struggle running the air-con all night, I dont have the capacity.

Yes Toowoomba broke a record yesterday, first time over 40c.

Glenn

__________________
"If it dont fit, use a bigger hammer."

The Back Shed
JAQ Software
Back to Top View Gizmo's Profile Search for other posts by Gizmo Visit Gizmo's Homepage
 
Boppa
Newbie
Newbie


Joined: 08 November 2016
Location: Australia
Online Status: Offline
Posts: 7
Posted: 13 February 2017 at 3:00am | IP Logged Quote Boppa

Waves hi @ Gizmo from Tara

Its definitely waaay too hot here, no aircon and only 2 fans in a caravan, all running from solar atm

Hit nearly 45 at one point yesterday, must admit I did a couple of `cool down' cold showers at the hottest part of the arvo, today's been better with a nice cooling breeze
Back to Top View Boppa's Profile Search for other posts by Boppa
 


If you wish to post a reply to this topic you must first login
If you are not already registered you must first register

  Search the forums using Google.
In the news...
 
Post ReplyPost New Topic
Printable version Printable version
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot delete your posts in this forum
You cannot edit your posts in this forum
You cannot create polls in this forum
You cannot vote in polls in this forum

Powered by Web Wiz Forums version 7.8
Copyright ©2001-2004 Web Wiz Guide

This page was generated in 0.0781 seconds.
Privacy Policy     Process times : 0, 0, 0, 0.08