BTUs, Watts, Tons...cooling server rooms (or folding closets)

R

relic

[H]ard|DCer of the Month - August 2007
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1 Watt = 3.413 BTU
1 Ton = 12000 BTU = 3516 Watts (or the equivalent of melting 1 ton of ice per hour)

There are sensible vs latent heat load calculations to do, but for most locations that don't include anything that adds heat/humidity (windows, air leaks, appliances, people) you can rate your folding room's cooling requirements by using 75% of the rated cooling capacity of the cooling unit.

A 1 ton unit (12000 BTU) should be able to handle 2500 watts (8533 BTU) of heat generated. This is rarely a cut and dry situation, but since this is a subject important to us, and we have few HVAC prefessionals to help us on the forum.

Many things will influence the cooling requirements (windows, sun, humidity, etc) but this gives you a starting point to size your cooling. Whether you use BTU, Watts or Tons as a point of reference you at least have some idea where to start.

The sensible heat calculation is as follows:

hs = 1.08 q dt (1)
where
hs = sensible heat (btu/hr)
q = air volume flow (cfm, cubic feet per minute)
dt = temperature difference (oF)


I am not an HVAC engineer, and they would do a much better job of calculating what you need....but most of us are folding on a budget...we can't afford a full blown analysis.

Hope this helps. Anyone in the industry who wants to help would be welcomed. :)
 
That's watts is off

my 14000 BTU AC only draws 1100watts

It was the only portable AC unit with a 12.71 seer rating

BTU/W = Seer (if memory serves me)





 
Sunin, power draw and amount of watts of heat generated is not the same thing. My 12,000 btu ductless AC also draw about 1100 watts but is more efficient at cooling the whole condo. SEER is a indicator of efficiency so a higher number mean a higher efficiency unit (mine is 13 SEER but also a heat pump so in the winter, it will heat the condo much much more efficienly than baseboard heaters).

 
I am a mechanical engineer and HVAC consulting is what I do every day. I am pretty new still, but home server/folding farm rooms are actually pretty basic stuff. Anything I don't know, I have about 40 other mechanical engineers I can ask. Are there any specific questions anyone has?

 
Wheresatom said:
I am a mechanical engineer and HVAC consulting is what I do every day. I am pretty new still, but home server/folding farm rooms are actually pretty basic stuff. Anything I don't know, I have about 40 other mechanical engineers I can ask. Are there any specific questions anyone has?

Click to expand...

Cool! :cool:

Glad you are here and willing to help.

I plan on buying a ductless AC system for my folding/server room. I won't be purchasing until early next year since my room is still under construction.

I was thinking of this particular unit: Sanyo 12,000 BTU for about $1,500

p.s. the SEER rating is 16. I don't know how they come up with these efficiency ratings, but 16 sounds good to me.

p.p.s I think I want one that works in the cold. In other words, a unit that can chill the air when the outside air is very cold. I'm not sure how well my cold air intake ideas will work.
 
Pocatello said:
Cool! :cool:

Glad you are here and willing to help.

I plan on buying a ductless AC system for my folding/server room. I won't be purchasing until early next year since my room is still under construction.

I was thinking of this particular unit: Sanyo 12,000 BTU for about $1,500

p.s. the SEER rating is 16. I don't know how they come up with these efficiency ratings, but 16 sounds good to me.

p.p.s I think I want one that works in the cold. In other words, a unit that can chill the air when the outside air is very cold. I'm not sure how well my cold air intake ideas will work.
Click to expand...

I'd recommend a cheaper alternative:
http://www.target.com/Amcor-000-BTU...499011?ie=UTF8&index=target&rh=k:amcor&page=1

AMCOR 14,000 BTU for $479.99 with a 12.73 seer (not horrible) its 1/3 cost and more cooling! I have this unit :)


Cold air intake can be done very easily. This next year I'm going to do mine slightly different with fitting a sealed unit with hoses blowing directly into the server room to cool. It will look fugly but will put the cold air where I need/want it!

 
Sunin said:
I'd recommend a cheaper alternative:
http://www.target.com/Amcor-000-BTU...499011?ie=UTF8&index=target&rh=k:amcor&page=1

AMCOR 14,000 BTU for $479.99 with a 12.73 seer (not horrible) its 1/3 cost and more cooling! I have this unit :)


Cold air intake can be done very easily. This next year I'm going to do mine slightly different with fitting a sealed unit with hoses blowing directly into the server room to cool. It will look fugly but will put the cold air where I need/want it!

Click to expand...

This is the same one I'm using now (sold under a different brand name in Norway) and I'm getting a 2nd to use in my foling basement once the damn electrician comes and pulls a couple o' new powerloops down there.

I've kinda "reversed" this normal use of this unit tho for my livingroom. I've placed the unit itself outside, and taken the flexible tube for varm air exhaust and taped this to the top of the unit (where the cold air is exhausted), and put this tube thru the airhatch on the wall going into the living room.

It basicly dumps the cold air thru the tube now, and blows the warm air out behind the unit. Problem with this setup tho is that the unit itselfs shuts of the condenser if the ambient temperature outside drops below 18 degrees C.

Now, when it's like 5 degrees outside etc, it's OK, since it will fan this cold air in, but when it's 13-18 degrees outside, which it often is during evenings/nights now, the temprature inside will not come down as much as if the condenser was on all the time.

Is there any way to manually override this temperature-sensor, or remove it all together?


Any ideas?

(moving it inside would be smart, but the reason I've placed it outside is because it makes more noise than a 6-lane highway, and having it outside really makes it very silent hehe)
 
Sunin said:
I'd recommend a cheaper alternative:
http://www.target.com/Amcor-000-BTU...499011?ie=UTF8&index=target&rh=k:amcor&page=1

AMCOR 14,000 BTU for $479.99 with a 12.73 seer (not horrible) its 1/3 cost and more cooling! I have this unit :)
Click to expand...

I looked at those types of Air Conditioners as well, but I got the idea that they won't last long or are not as efficient as the other type. I don't want to waste my money... Wheresatom--- what do you or your experts say?

I'm not expert and I am willing to look at other ideas. That is why I posted here.

Thanks for the link, Sunin! You are right ... that is way cheaper.
 
Ah, nostalgia. I remember those Thermodynamics and Heat transfer classes. I am also a mechanical engineer, but have been out of college and for 5 years and have not been in the industry.

Those Seer ratings sound like the ratio of energy moved/energy used. for example a rating of 10 on a system that uses 1000 Watts of power when running will move 10,000 Watts of heat. This rating is not the same at all temps. If the condenser heat exchanger outside is kept at say 120 degrees F and the evaporator heat exchanger inside is at 60 degrees F, you have a 60 degree difference between the hot and cold side of the loop. The rating will be based on a certain delta T or temp difference. When delta T is higher the efficiency will be less. This is why your AC takes far less energy when you set the temp a couple degrees higher.
 
Those portable units have gained some popularity in the last couple of years due to their ease of installation (plug and play really) and their relative efficiency. We do not use them in the consulting industry mainly for 2 reasons.

1. They are a less professional solution due to their noise generation and eyesoreness(I swear that's a real word).
2. They lack versatility. Most models do not handle condensation so they will not dehumidify. This means with some that there are sensors to turn off the unit if condensation starts to develop. Humid days=no cooling. Thats no good.

I have specified ductless split systems many times. They are an easy product to deal with. With a low ambient outdoor kit (like you linked to) you can go down to 0 degrees F outside. That should pretty much handle it many places in the United States. Other places you might want to consider using your hot server room air to help heat your house if it is below 0 often outdoors. The ductless split systems are more efficient also. For something that depending on your region may run 365 days a year little increases in efficiency start adding up faster. They are nearly silent which would be good especially if you are going to spend much time in the room with it. With normal maintainance (clean the filter regularly) you can expect the split system to work for 10-15 years no problem.

Also, you do have to have a professional install the splits usually. You might want to get a pro to price the parts for you too, they might be able to do so cheaper.

Hope this helps.

 
That's really taking the addiction to a whole new level. You might as well just put a toll meter on the electrical outlet.

Carry on!



 
The unit I linked has a drain tube that you can vent out the window... and does a good job at getting moisture out of the room.

I sit at about 25% humidity in the spring with it on.

 
mwarps said:
That's really taking the addiction to a whole new level. You might as well just put a toll meter on the electrical outlet.

Carry on!
Click to expand...

yes, you are right.

Folding for the Cure is an addiction. I told my wife that just the other day.

I want a high efficiency machine to save on long term electric costs.

I will spend hundreds of dollars building my server room. Have you seen what insulation costs these days! DANG! Insulation is really expensive.
 
You could always use straw bale construction for your server room. That would be cheaper than insulation right? ;)

When you have the opportunity to get it right from new construction that is always the best option. You will be rewarded for research and planning Pocatello.

 
Wheresatom said:
You could always use straw bale construction for your server room. That would be cheaper than insulation right? ;)

When you have the opportunity to get it right from new construction that is always the best option. You will be rewarded for research and planning Pocatello.
Click to expand...


Straw Bales? I had a friend that built his entire home from this method. I know you are joking... but in all seriousness, it would not fit my needs since I have to build my server room within the existing walls of my home.

You think I will be rewarded? That is cool! :cool: My family thinks I am nuts! I was at home depot last week and I showed my son what it costs to purchase rigid foam insulation. He look at me like I was nuts. Sometimes I think I am nuts. I sure have spent a fortune on folding @ home.
 
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