Why temperature difference not more than 10 degrees

[COMAPRO]

I wonder what is the technical reason that the temperature indoors should not be less than 10 degrees of the temperature outdoors. If the temperature outside is, for example , 95 degrees then the temperature inside should be 85 but that is still unconfortable. Dont you think so guys ?

 

[pennpoint]

COMAPRO
I do not know where you got your number "not less than 10 degrees indoor/outdoor".

But lets say someone said number should be 15 degrees then you'd be more comfortable (using your example).
Seems to me that, not less than means it can always be greater than.

Whats your question?

pennpoint

 

[COMAPRO]

Thank you pennpoint for your promtly reply. the statement " not more than 10 degrees diference I have read it in acouple of technical documents but they do not define the technical reason ? does it have to do with the health of a person or what ? I am an industrial engineer and I am not used to take anything for right if is not supported with a technical ground . the reason I am after an answer is because if that is true , one can get big energy savings not allowing people to set the cooling thermostat too low allowing the compresor to run longer . It seems you have not heard about it .Anyway thank you for your try

 

[IRstuff]

a> a 10° change is quite drastic, even that small a change will seem quite cool to someone who's been outside.

b> thermal shock. I've gone from 90° outside temp to 65° interior temp and, at least for me, I get a thermal shock, because the drastic temperature change is aggravated by the apparent windchill within the building.

TTFN

 

[pennpoint]

COMAPRO
More or Less?
Your header question states More than
But your post talks of less than? Which is it?

IRstuff: I will agree that a temperature drop you describe can be a bit shocking to some people. But then coming in from 103 outside to 78 (25) can feel real good. You ever been to Nevada or Arizona in the summer? Remember when you was a kid and played in the water on a real hot day. How cold do you think that water was. Maybe 20-30 degrees different than the air temp, but did you even care. I bet NO!
Temperature comfort is a personal & metaphysical thing. In my office a co-worker is constantly too warm, while Iam too cold so I wear a jacket he uses a fan.
No matter what temperature you maintain, someone will not be comfortable with it. Be prepared..

Regards
pennpoint

 

[COMAPRO]

Pennpoint , I am trying to become an expert in energy savings issues and I see that here at home the employees set the thermostst temperatures very low 55 to 65 degrees and they do not realize that the compressor has to work all day long trying to reach the temperature setting, specially if the outside temperature is very high and therefore consuming a lot of energy , money that they do not pay but the employer does . With this scenario if I could explain them from a technical standpoint of view that is not correct, lets say if the temperature outside is 100 , to pretend to have 78 inside . Again , the thermal schock , IRstuff , mentioned , is bad for the health ?

 

[IRstuff]

The Chinese think so...
My mother always claimed that was bad for your health, and while I ignored much of her advice at the time, much of the other stuff that she was touting 30 yrs ago, such as the benefits of tea, have recently been borne out.

I think that under the conditions described, the office environment winds up too dry, because the absolute humidity is too low. This dries out skin and sinuses, so there are associated dermatitis and potentially other dry skin conditions. Likewise with drier sinuses.

I've noticed that my office building's A/C has been mucked with so much over the years that the office temperatures are all rather random, but the hallways are always chilly during hot days.


TTFN

 

[1969grad]

Comapro are sure you are going the right direction with this one. I normally limit the inside temp of an ventilated only (no air conditioning) building housing equipment to 10 F above the ambient. Perhaps you should re-read the spec and verify.

Otherwise, the only situation I could think of where the 10 F requirement might apply is a building using evaporative cooling.

 

[COMAPRO]

hi 1969grad , I am talking about a bulding that has air conditioning all year around and about employees that they dont care how high electricity bill goes. I have been hired by the employer to find out what would be the right setting that he wont pay too much for electricity and in the other hand the employees wont sweat.

 

[lilliput1]

ASHRAE has a plot of the comfort zone on the psychrometric chart. Temperature and humidity defines the zone. The setting of the thermostat may not correspond to the actual temperature of the space. The system may not have sufficient capacity to achieve the desired temperature.

 

[imok2]

In the many years I have been a service tech and been responsible for the air conditioning in many large buildings , I have found that it is impossible to satisfy all of the clients, there for, I would always try to use the comfort zone as my guide and maintain 71*f 50% humidity at an air flow velocity of 30 fpm in winter and 76*F 50% humidity at an air flow of 50 fpm in summer. This should satisfy about 85% of the clients. The rest..Well..at times you have to be a little devious sometimes it works and then of course you have the hard core. But you must always maintain a sense of understanding and good social graces.

 

[COMAPRO]

thank you guys for all your tips. I am gonna set thermostat at 75F and see how long it takes the cooling system to bring the outside
humidity, 90% , to 50% looking at a relative humidity meter

 

[rogzog]

I have noticed that often when the thermostat is accessible to anyone who feels like adjusting it, they often go to extremes and set the t-stat way low or way high. I suppose they think that the temp will change faster by doing so. That is why t-stats are often enclosed in locking covers to deter random changes of the t-stat settings by any one who feels uncomfortable. I agree that the 10-degree maximum difference is not reasonable for all conditions. If it is 20 degrees outside I doubt that you will be heating to only 30 degrees inside, right?

I have seen some DDC controlled systems where the room temperature sensors looked like t-stats but actually were not able to affect the temp setting, that was controlled from the control program in the computer. People would think they were setting the temp to what they wanted but actually they were not.

 

[IRstuff]

The question for for "less than".

TTFN