pet resort generator

ceb58

ceb58

Senior Member
Location
Raeford, NC
I need some help/ advise on sizing a generator for a pet resort. Information I have is they used 118,172 KwH in a 12 month period now with that said my calculations come up to a average of 56 amps per hr.
118172 * 1000 / 240v * 8760 hrs per year
Now my question is how much larger should I go. The building has 3 - 5 ton A/C units with 3 - 10Kw heat strips in each air handler and a 4 ton A/C with 10 Kw heat strips. My concern is the start up of the A/C units although I know they all will not try to start at one time but being overly cautious.
 
Something is off worth your math…
118172 kWh is a LOT of energy, that’s 118 MEGA watt-hours, enough to power around 150 homes for a YEAR!

Regardless, extracting demand from annual keg use is fraught with problems. Theoretically, 118MWh could be 118 MW for one hour, then zero for the rest of the year, or it could be 9.8MWh per month. So even if it is averaging 9.8MWh per month, that could be 327kWh per day, or 500kWh on some days and 100kWh on others, meaning you have to be ready for the 500kWh days! And even then, that could be 16kW every hour, or 12kW per hour for 23 hours and 1 hour where it’s 100kW, in which case you have to be ready for the 100kW hour. See the problem?

Ask your utility for a peak demand value, they should have that if it’s a commercial business, even if they don’t charge the customer a peak demand charge.
 
You cannot use kWh over long periods of time to determine kW demand. The demand could be super high for a few minutes and then 0 for the rest of the time. That will not allow your generator to pick up the load if you sized it based on the energy divided by time.
 
ceb58 said:
I need some help/ advise on sizing a generator for a pet resort. Information I have is they used 118,172 KwH in a 12 month period now with that said my calculations come up to a average of 56 amps per hr.
118172 * 1000 / 240v * 8760 hrs per year
Now my question is how much larger should I go. The building has 3 - 5 ton A/C units with 3 - 10Kw heat strips in each air handler and a 4 ton A/C with 10 Kw heat strips. My concern is the start up of the A/C units although I know they all will not try to start at one time but being overly cautious.
Click to expand...
"Amps per hour" makes no sense. Amperes is a rate, not a quantity.
 
The electric heat strips are far in excess of the AC load IMHO. You have 40kw of electric heat which is 167 amps. (I am assuming) 240 single phase power. 208 3 phase would be 111 amps if a balanced load. 480 3 phase would be 49 amps.. You only need the greater of the heat or AC loads.

40kw is 137,000 btu of electric heat.
 
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