I'm absolutely fine with moving to new tech, but I'm trying to find efficiency numbers for all these cheaper COBs because I pay almost $.30/kWhr. Paying an extra couple bucks to save $$$ over the course of a year is absolutely worth it. Is there a chart comparison for these? Currently I'm running CXB3590s at 1050mA and dropping down to 700mA shortly.
the math is easy. a 1000W DE pulls 1100+ at the wall. a rig with cree at 50-55W or luminus/veroC/clu1825 at 70-75 W should replace a DE with roughly 700 cob watts or 750 wall watts
in this case your savings is 350W, or 0.35KWh (per hour)
at 1212 there are 4380 hours in a year
annual savings = annual hours x kwh savings x rate
4380 x 0.35 x 0.3 = $460
thats straight electrical cost of lights alone and does not consider the cooling you wont need for the 350 less heat watts you are producing, which could bump that savings by 10% or more. also the bubl and reflector changes which are at least $30-50 year usng the cheapest bulbs you can find and stretching out over a year
so lets look of the cost of that cree rig to do the above
say you want to cut your cob wattage in half to 700 mA. lets say a 700W (1400 mA) cree rig is somewhere around
$35 x 14 chips= $490
700W in CC drivers = $200
heatsinks and holders etc (if you go pin fin) = $ 260
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$950
assuming a bargain gavita/epap/whatever and a couple bulb changes over a few years is $450
you paid $500 more to save $460/yr in electricity- seems like a fair investment that will keep on returning year over year
the trick is calculating diminishing returns.
using the "cut current in half and bump efficacy by 10%" rule of thumb, the same cree rig (in PAR/lumens) at 700 mA would look something like say 600 cob watts/675 at wall:
$35 x 24 chips= $840
700W in CC drivers = $200 (same- but with CC drivers you dont have the clearest upgrade path unless you run strings in parallel which has risks with a non-voltage limitable high voltage CC driver)
heatsinks and holders etc (if you go pin fin) = $300 (downsizing heatsink size to small pinfins or star extrusions)
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$1340
in this case youre spending almost $400 more to save another 0.075 KWh
4380 x 0.075 x 0.3 = $99/yr -> 4 year payback - not as great as the case above