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Calculating The Size of a Server Room Air Conditioner
A quick guide to show you how to work out your requirements for an air conditioning unit for your Server Room or Data Center.
In principle it’s easy to calculate the size of air conditioning unit you need for your Server Room, just add together all the sources of heat and install an air conditioning unit that can remove that much. In practice it’s rather more complicated. This guide does not go into detail of every possible heat source, but it should give you an idea of the amount of coling you might need.
Fire regulations often require that Server Rooms have levels of insulation far above that of a normal office. Providing sufficient cooling is essential to ensure reliable running of servers, routers, switches and other key equipment. Failure of the air conditioning can have serious consequences for the equipment itself and for your company. Early warning of problems and spare capacity in the cooling system are both highly desirable.
Calculating Heat Load
The amount of heat generated is known as the heat gain or heat load. Heat is measured in either British Thermal Units (BTU) or Kilowatts (KW). 1KW is equivalent to 3412BTUs.
The heat load depends on a number of factors, by taking into account those that apply in your circumstances and adding them together a reasonably accurate measure of the total heat can be calculated*.
Factors include:
- The floor area of the room
- The size and position of windows, and whether they have blinds or shades
- The number of room occupants (if any)
- The heat generated by equipment
- The heat generated by lighting
Floor Area of Room
The amount of cooling required depends on the area of the room. To calculate the area in square metres:
Room Area BTU = Length (m) x Width (m) x 337
Window Size and Position
If, as is quite common, your Server Room has no windows, you can ignore this part of the calculation. If, however there are windows you need to take the size and orientation into account.
South Window BTU = South Facing window Length (m) x Width (m) x 870
North Window BTU = North Facing windows Length (m) x Width (m) x 165
If there are no blinds on the windows multiply the result(s) by 1.5.
Obviously if you are in the Southern Hemisphere you would swap the conversion factors as the heat on North facing windows is then greatest.
Add together all the BTUs for the windows.
Windows BTU = South Window(s) BTU + North Window(s) BTU
Occupants
Purpose built Server Rooms don’t normally have people working in them, but if people do regularly work in your Server Room you will have to take that into account. The heat output is around 400 BTU per person.
Total Occupant BTU = Number of occupants x 400
Equipment
Clearly most heat in a Server Room is generated by the equipment. This is trickier to calculate that you might think. The wattage on equipment is the maximum power consumption rating, the actual power consumed may be less. However it is probably safer to overestimate the wattage than underestimate it.
Add together all the wattages for Servers, Switches, Routers and multiply by 3.5.
Equipment BTU = Total wattage for all equipment x 3.5
Lighting
Take the total wattage of the lighting and multiply by 4.25.
Lighting BTU = Total wattage for all lighting x 4.25
Total Cooling Required
Add all the BTUs together.
Total Heat Load = Room Area BTU + Windows BTU + Total Occupant BTU + Equipment BTU + Lighting BTU
This is the amount of cooling required so you need one or more air conditioning units to handle that amount of heat.
So what size of unit do I need?
Small air conditioning units have a cooling capacity of between 5000 and 10000 BTUs. Small units may fit in windows, venting to the outside world.
Larger units may be rated in tons of cooling. 1 ton of cooling is equivalent to 12 thousand BTUs.
Disclaimer: This calculation is intended as a rough guide only. Complete accuracy cannot be guaranteed. Before you decide on an air conditioning unit you should commission an audit from a suitably qualified air conditioning equipment specialist or installer.
Related articles:
- Business Continuity and the Data Centre
- Skimp on Server Room Air Conditioning? At Your Peril
- Server Room Monitoring Introduction
- The Heat Is...On
- Improve Data Centre Monitoring
- High Density Monitoring-Verification and Auditing in the Data Centre
- Temperature Monitoring ASHRAE Standards Proving a Hot Topic in Data Centre Management
- Customising the Web Interface on the AKCP SecurityProbe
- 5 Things to Know About Data Centre Temperature
- Monitoring the Operational Status of Computer Room Air Conditioners (CRAC)
Comments
cooling
how much energy does air con use to cool 1kw?
what is the value??
greeting,may i know wat is the value for 337 at floor area of the room?? the window value 870,165,1.5 ..and why the equipment must times by 3.5??and the lighting too...tq very much^^
pool air con load
i have swimming pool are 72 sqm ,,,pool area 30 sqm ,,,2 sides and roof of the pool made of polycarbonite multiwall
what the AC capacity required in ton ?
i will install dehumidifier capacity 1500 m3/h and evaporation rate 3.6 l/h
good to see the questions
very clear picture about the heat load calculations..however thanks for web and all
need help - compressor is freezing
I am operating a test system in Dubai that have 2 trailer type rooms (8'x10') each. Room 1 has the AC mounted on one side of the room and lots of test equipemt that generate heat, room 2 is a control room with 1 3'x3' window and 4 people. Room 1 has 5 AC vents (14"x6") each, room 2 has 1 vent (14"x6"). The return from room 2 to room 1 is about (14"x6"). The thermostat is in room 2. Ambient temp is Dubai is about 100 deg F. I usually set the thermostat to 70 Deg F. After few hours of operation, the Compressor freezes over. The objective is to keep Room 1 much colder than room 2 due to heat being generated in room 1. Are the sizes and quantity of the vents sufficient? if Not please help.. also why is my compressor freezing over? The AC system is 6 tons.
Thanks
Try to check the pressure on
Try to check the pressure on the system.Maybe lack of freon charge or overcharge
heat load
Dear Sir
I have total heat load around 25270W or 25KW so how I can calculate the capacity of air conditioning system in Ton or BTU .
Thanks
best regards
Moha'd
for 25kva 25 kva=25 x
for 25kva
25 kva=25 x 0.8(power factor)
=20kw
for this 5.5 tr Ac is required
Capacity in ton=25/3.517
Ok
calculate the capacity of air conditioning in ton or BTU
hello
i think it is sample ,all you need to know and here its
1 BTU=0.293w ,so 25000w=x
x=25000/0.293=85324BTU
so the capacity you need it in metric ton =6.5ton and in BTU=85324.
salah .sudan
regarding the water flow
Dear Sir,
Please help us for the normal ahu with the chilled water coil what shall be be the required flow rate of water. to get the cooling efficiency at the best.
regards,
umesh
Sensible Cooling LoadS
HI here
You can't simply just add the loads together and choose a unit that will satify total
Server room load or (machine load) is a sensible load and all air conditioner coils have a sensible heat ratio SRC
This can be around .6 to .7 depending on the coil size and brand.
This factor must be taken into consideration.
hear load
hope when we calculate the LxWx337 it should be in feet then calculation become ok but when we calculate in Mtr. then it showing very low BTU unit
it's indicated in meter
it's indicated in meter (m)...
East and west window heat load?
What is the multiply factor to use for east and west window?
Equipment loads
I am busy Designing Server room HVAC. I ask IT guy to give me the actual kW electrical load for racks. He does not understand equipment rating. what method can i use to get those load?
Really?
And this guy you are talking to works in IT?
aircon
hi
is ther standerd convetion for room size = btu arcon need to use.
thanks
Hi....
Why you didnt consider East& West windows for windows heat load calculation?
window computation
which is the correct formula in Window Computation? is it
Total Area = L x W x No. of equal size window? or....
Total Area = L x W x 165? / 170? and also where are these or how did you get this 165 and 170?
What is the Standard Heat Load Calculations?
i was researching for heat loads calculations and i end up with 2 identical measurements. but some numbers are so confusing because the values of of deriving the numbers is changing. so, maybe you can help me the standard number of calculating heat loads. like for example:
1. The Floor Area computations
what is the difference in the calculating the Floor Area in BTU
L (in ft.)x W (in ft.)x 31.25 to: L (in meter)x W (in meter)x 337?
2. Windows Size and Positions
is the calculations of North Window BTU is = Area x 164? or 165?
and the South Window is equal to Area x 868? or 870?
3. Occupants
in calculating the number of occoupants is it....
Total Occupants is equal to number of occupants multiply by 400? 500? or 600? (total occupants = no.of occupants x 400? or 500? or 600?
sir, i am so confused about this. could you pls helped me? i am looking forward to hear from you in enlightening me about the Heat Load Calculations. Thank you sir. God Bless.
how to calculate heat load of the matel base cieing
How to calculate the heat load of matel based cieling like acrelic & iron deka seat cieling , my confrence hall size is 75*41*16,pls tell me how tr.is require for this area
UPS cooling
Hi, does the about calculation include cooling the UPS?
If i have to calculate heat
If i have to calculate heat load of a cooling plate (used to cool mass that is kept on it) using water circulation as cooling medium.. what all factors do i need to consider ????
Data Center Cooling Caculation
Device Watts Qty Total Watts BTU
C6509E 6000 2 12000 40944
C4948 300 2 600 2047.2
C2951 340 2 680 2320.16
MCS 7835 780 2 1560 5322.72
MCS 7816 351 1 351 1197.612
MCS 7825 351 1 351 1197.612
C2960S-24PS-L 276 4 1104 3766.848
Cisco 2901 150 2 300 1023.6
ASA 5520 190 2 380 1296.56
CPS-MSP-1RU 300 1 300 1023.6
CIVS-MSP-4RU 900 6 5400 18424.8
D9854 37 9 333 1136.196
D9887B 200 5 1000 3412
DCM 9901 225 2 450 1535.4
Lightning Fixtures 18 8 144
GRAND TOTAL 24953
LIGTNING FIXTURES TOTAL BTU 2448
TOTAL BTU FOR EQUIPMENT 84648.308
FLOOR AREA BTU 7218.54
TOTAL BTU 94314.848
1 TON = TO 12000 BTU/h 7.859570667
Required CRAC 8 TONs
Heat Load
Is a 150KW heat load the same as 150KW electrical load?
SW
This depends on the type of
This depends on the type of cooling equipment you use
- For DX type: Factor is 1.0
- For Chiller Systems: Factor is 0.7
Is a 150KW heat load the same as 150KW electrical load? Read mo
52 ton
Heat Load
both kW for heat and kW for power are the same units. If all of the electrical equipment is in the same space then all 150 kW becomes heat
TR
If 3 TR is the cooling load,so i am getting dehumidified supply CFM is only 400!! why? help me out
problem
why we consider only ERSH and ERLH for dehumidified supply CFM,why we are not considering Outside air load
hello good evening..please
hello good evening..please tell me how to solve the area for a air conditioning unit for my convention center..the size of my convention center is 27x45 meters then what must the size of my ACCU??thank you!
hello good evening..please tell me how to solve the area for a a
hello
brother require some data...... convention center total people...total other load...equipment load...then i can ur soluation
in your celcoletion not
in your celcoletion not incould abmnet temp and room required temp..
for exampal....
i want to mad coold storig.
my requride temp -5 c
ambent temp 40 c
room btu 2000 btu
have 4 windows 1 est,1west,1 north,1 south
and size 1 m x4
south window 4 x 460btu
1840 btu
north window 4 x 165 btu
660 btu
how can celcoletion TR pliez guide me
hai good evening
hai boss,
i thing so it should be total 3.5 tone because u did not mensation the product heat load and u want -5c
thank u
RAC
in your celcoletion not incould abmnet temp and room required temp..
for exampal....
i want to mad coold storig.
my requride temp -5 c
ambent temp 40 c
room btu 2000 btu
how can celcoletion pliez guide me
Window Orientation
Hi all
Why do you only use North and South windows? What if i have east or West facing windows?
thanks
ade
North or south facing windows are only considered because they both face the equator so to say.The closer the region is the the equator, the higher the solar gains.
i hope this has helped
about walls
Anonymous;
in calculating the heat gain through walls, you only consider two of them, no matter haow many windows do you have. those windows you need to consider in your calculation are those facing to where the sun rises and and sets. however, you only allow to use 1 window to add to your heat load calculation, the one that has higher value of heat gain.
RAC
i have 4 windows 1 est,1west,1 north,1 south
and size 1 m x4
south window 4 x 460btu
1840 btu
north window 4 x 165 btu
660 btu
est and west how btu celcolet?
Answer
Sun Set and Sun Rise happens in east and west, so there is lots of heat gain requring more capacity of cooling units to be installed.
I want to know how to
I want to know how to calculate the BTUs of computers and computer's components such as processors,monitors etc.
How tou convert KVA in tones
i have a problem
my TI adviser has requested a 5 tones cooling unit in our server room
the request is for 40KVA power in our server room
our buider install a 3.3 tones cooling unit and is telling me that it is enougn
who is wrignt?
thanks for your help
pl. see below 40KVA * 0.8 (
pl. see below
40KVA * 0.8 ( Power factor ) =32KW
32KW = 32000*3.413 BTU / Hr = 109200BTU /Hr
12000BTU / hr = 1 Ton
so u have to use 9 TON AC.....
So both r wrong...
i need kVA
HAY
135TR Unit kva and 250tr kva
rectification of the formulas
from the formulas;
Area = L X W x 337
Lighting = Total lighting watts X 4.25
Euipment = Total watts of equipments X 3.5
Occupants = N X 400
where does the exact value of 337, 4.25, 3.5 and 400 came from? can you please show me the Long method of that??
Please help me.
Thanks alot..
DC RECTIFIERS
I have a small problem in finding the right AC unit for a shelter housing two DC rectifiers for clorinating the sea water.
the name plate details are as follows
480Volt X 115Amps
watts 110400Watts
Btu 375360BTu
TR 31.00
or is there any thing other multiplication factor? Please help me i am bably in need of some ones help
calculate the capacity of air conditioning in ton or BTU
hi
one BTU=0.293w,so 110400w/0.293=375360BTU
one ton =12000BTU,so 375360/12000=31.4 so this all
salah,sudan
Electrical panel connecting load.
the electrical panel connecting load can be directly used to calculate the heat load.
or Electrical load kw is different with heat kw.
HVAC
TR capacity required for 682400BTU heat load
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