HVAC Running Cost
HVAC Running Cost
(OP)
Hi all,
I'm new to this site...please be gentle!
Is there a "rule of thumb" for air conditioning operating cost based on the amount of cooling required? I'm trying to evaluate how much it will cost (for electricity) to operate an A/C to cool 60kW of heat in a sealed room.
Any help is greatly appreciated.
I'm new to this site...please be gentle!
Is there a "rule of thumb" for air conditioning operating cost based on the amount of cooling required? I'm trying to evaluate how much it will cost (for electricity) to operate an A/C to cool 60kW of heat in a sealed room.
Any help is greatly appreciated.





RE: HVAC Running Cost
The performance indicator you are interested in is Coefficient of Performance (COP). For a cooling application, COP = cooling effect / power input to operate the system.
Manufacturers will probably list COP in the technical data for the system. However, what is listed is at some set of conditions (combination of evaporating temperature, condensing temperature and load). These conditions should be stated (but frequently are not), and will probably be different from your condtions. COP is not constant, it is a function of both evaporating and condensing temperature.
RE: HVAC Running Cost
1.2 kw/ ton if air cooled. Say 0.8 Kw/Ton for water cooled, including chilled water pump & condenser water pump.
Full load hours depend on location & occupancy type. It could be as high as 2000 & as low as 1200.
RE: HVAC Running Cost
RE: HVAC Running Cost
(cost of electricity)*(consumption)*(hours of operation/day)*(days of operation/year)=cost for one year
Note that power consumption is usually different in cooling and heating modes, so do the calculations for both and add them up.
If you divide the cost by the capacity of the A/C unit, you will get an estimation for the cost/kW.
Remember that one Ton = 3.52 kW. For all unit conversions, try downloading "Convert" from: http://www.joshmadison.com/software/convert/
Hope this is useful!
RE: HVAC Running Cost
Equal to 12,000 BTU/hr or 3.52 kW.
RE: HVAC Running Cost
_ MUCHO Tons ... in the 25-Ton range.
Considering equipment S.H.R. and average efficiency,
= $60 per day or $21,900 per year
( ~$2.50 /hour based on $0.10/kW)
Just use a 7000 CFM Exhaust fan,
to limit area temp increase to ~ 25'F
__ ~105'F when it's ~ 80'F outside or
__ ~ 65'F when it's ~ 40'F outside.
Assuming 60kW heat is from a process
(i.e. heater, furnace)
NOTE: One-Ton equipment does NOT take 3+ kW to operate.
Power requirement is likely close to 1.0 kW/Ton
depending on system type ( DX or chiller)
and actual overall efficiency.