HVAC pairing with LEDs (BTU calculation)
- Thread starter Growmau5
- Start date
ttystikk
Well-Known Member
Right. The actual conversion process that we are powering with all that light doesn't take up very much of it, lol. Figures!
Transpiration is another matter entirely. If I run all my lights in an empty room, the climate control system can't keep up. When it's full of plants, the climate control system doesn't even break a sweat- and I get lots of 5 gallon buckets full of distilled water from my air handlers.
I've discovered that even if vent air coming into the room is warmer than the room itself, it can still be a net cooling influence once the plants have added moisture to it.
alesh
Well-Known Member
Thanks. This is exactly what I was looking for.
alesh
Well-Known Member
Probably due to this effect https://en.wikipedia.org/wiki/Enthalpy_of_vaporization
ttystikk
Well-Known Member
Exactly, same principle as a swamp cooler. It's how plants maintain their leaf temps without burning. Since the whole point of the exercise is to grow plants, it seems to me that it would be an opportunity missed not to take full advantage of the phenomenon.
Merkin Donor
Well-Known Member
So this thread prompted me to do a little experiment with lights and the results were interesting. Not being a scientist and probably only average smart for a city boy I can’t claim that my results will hold up under scrutiny. But I do strongly feel that the issue warrants more study and it will only strengthen the benefits of LED lighting.
I do deep energy retrofits on residential buildings in SoCal and while I’m relatively new to HVAC (3 years) what I’ve learned is that most HVAC contractors either don’t know how or don’t bother to spend the time to do things right. In California only about 3% of all residential HVAC jobs are done with a permit. The average traditional split system installed after 2007 operates at about 55% of its rated delivered efficiency. A recent study found that of the 80 systems measured, not even one met the HVAC equipment manufacturers’ requirement to limit system pressure drop to less than 0.5” WC to deliver the equipment’s rated efficiency. Has anyone been shown what the delivered efficiency of their newly installed HVAC system was? We know that we can install a 2 ton system in a 3,500 ft2 house (new construction) in Redding, CA and keep the place comfortable (it can get damn hot there) and have heating & cooling costs that are under $400.00 for the entire year. I guess where I’m going with all this is when I see “rule of thumb/one number for all luminaries” type calculations being used it makes me think that there are most likely some significant savings to be had if we take actual measurements and figure out what’s really happening.
One more disclosure before I lay out my little test and that’s that I’ve never worked with or even touched any type of glass bulb grow light so I may look like a dumbass when this is all said and done.
I have a 4x4 grow tent inside my 8x12 room with some clones and seedlings inside it. It’s currently lit with a (4) CXB3070’s powered by a Meanwell 185-1400 driver on a 36” heat sink (pulling 237 watts). The tent was closed up and running 76.1°F and 48% Relative Humidity so I set my timer for 15 minutes and turned off the exhaust fan. After 15 minutes the ambient temperature had risen 4.2°F and RH had stayed the same (48%). I flipped the fan back on and internal temps quickly returned to 76.1°F. I took the only glass bulb light I had available which is a small halogen work light and tested it at 133 watts. I don’t have my thermal camera with me so I couldn’t check out its operating temps. I installed it in the tent and turned off the fan and started the timer. Interestingly enough at 7.5 minutes the temp had risen by 2°F and the RH dropped by 1%. At that point I thought “a-ha, I knew it!” but strangely (for me anyway) the increase started to level off and after 15 the temp was only up 2.7°F but RH fell to 46.5%. At this point the interior of the tent felt noticeably hotter and muggier even though RH was dropping.
That’s my story; I’m stoned and sticking to it. I’ll think about it more tomorrow which by that time you guys may have told me how much of an idiot I am because HPS and halogen bulbs don’t behave in a similar manner. But I still strongly feel that actual measured heat load calculations along with correctly installed HVAC systems operating at 100% or more of rated capacity will allow us to drastically reduce our operating costs. And that’s money in the bank……..
I do deep energy retrofits on residential buildings in SoCal and while I’m relatively new to HVAC (3 years) what I’ve learned is that most HVAC contractors either don’t know how or don’t bother to spend the time to do things right. In California only about 3% of all residential HVAC jobs are done with a permit. The average traditional split system installed after 2007 operates at about 55% of its rated delivered efficiency. A recent study found that of the 80 systems measured, not even one met the HVAC equipment manufacturers’ requirement to limit system pressure drop to less than 0.5” WC to deliver the equipment’s rated efficiency. Has anyone been shown what the delivered efficiency of their newly installed HVAC system was? We know that we can install a 2 ton system in a 3,500 ft2 house (new construction) in Redding, CA and keep the place comfortable (it can get damn hot there) and have heating & cooling costs that are under $400.00 for the entire year. I guess where I’m going with all this is when I see “rule of thumb/one number for all luminaries” type calculations being used it makes me think that there are most likely some significant savings to be had if we take actual measurements and figure out what’s really happening.
One more disclosure before I lay out my little test and that’s that I’ve never worked with or even touched any type of glass bulb grow light so I may look like a dumbass when this is all said and done.
I have a 4x4 grow tent inside my 8x12 room with some clones and seedlings inside it. It’s currently lit with a (4) CXB3070’s powered by a Meanwell 185-1400 driver on a 36” heat sink (pulling 237 watts). The tent was closed up and running 76.1°F and 48% Relative Humidity so I set my timer for 15 minutes and turned off the exhaust fan. After 15 minutes the ambient temperature had risen 4.2°F and RH had stayed the same (48%). I flipped the fan back on and internal temps quickly returned to 76.1°F. I took the only glass bulb light I had available which is a small halogen work light and tested it at 133 watts. I don’t have my thermal camera with me so I couldn’t check out its operating temps. I installed it in the tent and turned off the fan and started the timer. Interestingly enough at 7.5 minutes the temp had risen by 2°F and the RH dropped by 1%. At that point I thought “a-ha, I knew it!” but strangely (for me anyway) the increase started to level off and after 15 the temp was only up 2.7°F but RH fell to 46.5%. At this point the interior of the tent felt noticeably hotter and muggier even though RH was dropping.
That’s my story; I’m stoned and sticking to it. I’ll think about it more tomorrow which by that time you guys may have told me how much of an idiot I am because HPS and halogen bulbs don’t behave in a similar manner. But I still strongly feel that actual measured heat load calculations along with correctly installed HVAC systems operating at 100% or more of rated capacity will allow us to drastically reduce our operating costs. And that’s money in the bank……..
SupraSPL
Well-Known Member
So with 237W of COB dissipation the temp rose from 76 to 80.1F and with 133W of halogen the temp rose from 76 to 78.8F? Sounds about right. How was the temp measured, was the sensor in the light where it would be exposed to the infrared output of the halogen?
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ttystikk
Well-Known Member
Fascinating stuff about how poorly most AC systems are installed!
If you're an efficiency expert, I'd like to pick your brain sometime.
I use water chillers, I don't do anything with the Freon inside them- I just run waterlines to them and then use the cold water for environmental control. How would you suggest I go about doing an efficiency audit on the system to ensure I'm getting what I'm paying for?
Great post, wish I could like it twice!
Merkin Donor
Well-Known Member
Other than class time in NCI commercial air & hydronic balancing I've never played with chillers. But post what you have because I'm sure NCI will have a procedure to perform an audit. A lot of the stuff you would need to do isn't hard, it's just that the equipment needed is kind of expensive. Find out if your local HERS Rater uses cannabis and hook'em up... They've got the tools to find out if you can put a couple hundred per month in savings and that could be 4-5 grand at the end of the year. I'd be cool with that.
edit to add link
http://contractingbusiness.com/residential-hvac/hvac-game-changer-calculating-system-btus
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Merkin Donor
Well-Known Member
The sensor was right at the top of the canopy. I probably should have used a new bulb.
salmonetin
Well-Known Member
...pardon MD for another offtopic mine...
...im wrong... i missing some correct value...
...some days i 
...sorry...
now the correction... thanks to Supra Alesh ...and Guod for a great mental seed...
. what a three...
You calculated it right, too, but forgot to multiply it by 3 as you assumed 3-COB setup. ... Thanks a lot Alesh...
.....from my pov... i forgot multiply it by 3 the
= Photometric Flux ...7350 its value for only one cob.... 22050 its 3 cobs
(3) cxa3070 light @1400 mA
Vf 50ºC = 37,30 V ...If = 1400 mA ....Diss W 50ºC = 52,22 W * 3 = 156,66 Diss W
note.... one 3070 its 52,22 W.... three = 156,66 W...
...% 50ºC = 43,31 % ...PAR W... 156,66 * 0,4331 = 67,85 PAR W ... 156,66 - 67,85 = 88, 81 W heat...
...then my math on heat calcs with par w are ok... thanks Supra and Alesh......
...other way with LER... ...from other Guod mental seed...
https://www.rollitup.org/t/cob-efficiency-spreadsheets.865238/page-7#post-11703777
= Photometric Flux = ...I use Lm 50ºC = 7350 ...but 3 are 22050...thanks Alesh...
if i use Lm / Watt 50ºC = 140,75....
By dividing Luminous Efficacy by LER (that 140.75 / 325 in your example) you get Radiometric Efficiency (0.433 aka 43.3%).
....Thanks again Alesh...
...then i use lm @ 50ºC by three... 22050 lums
LER = 325
22050 / 325 = 67,8461... 67,85
Pheat = 156,66 Diss W – 67,85 = 88,81 Heat W....
= Radiant Flux
...then
= 67,85 ...its the Radiant Flux value....
...now the values are ok to my pov... thanks you guys...
...Wilson.... ...time to shoot my mouth and back to the cavern...
.,.the heat math close my circle...bye bros...
Saludos
...im wrong... i missing some correct value...
...some days i ...sorry...now the correction... thanks to Supra Alesh ...and Guod for a great mental seed...
. what a three...You calculated it right, too, but forgot to multiply it by 3 as you assumed 3-COB setup. ... Thanks a lot Alesh...
.....from my pov... i forgot multiply it by 3 the
(3) cxa3070 light @1400 mA
Vf 50ºC = 37,30 V ...If = 1400 mA ....Diss W 50ºC = 52,22 W * 3 = 156,66 Diss W
note.... one 3070 its 52,22 W.... three = 156,66 W...
...% 50ºC = 43,31 % ...PAR W... 156,66 * 0,4331 = 67,85 PAR W ... 156,66 - 67,85 = 88, 81 W heat...
...then my math on heat calcs with par w are ok... thanks Supra and Alesh...
......other way with LER... ...from other Guod mental seed...
https://www.rollitup.org/t/cob-efficiency-spreadsheets.865238/page-7#post-11703777
if i use Lm / Watt 50ºC = 140,75....
By dividing Luminous Efficacy by LER (that 140.75 / 325 in your example) you get Radiometric Efficiency (0.433 aka 43.3%).
....Thanks again Alesh...
...then i use lm @ 50ºC by three... 22050 lums
LER = 325
22050 / 325 = 67,8461... 67,85
Pheat = 156,66 Diss W – 67,85 = 88,81 Heat W....
...then
...now the values are ok to my pov... thanks you guys...
...Wilson.... ...time to shoot my mouth and back to the cavern...
.,.the heat math close my circle...bye bros...
Saludos
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ttystikk
Well-Known Member
I have an appliance repair/HVAC tech who's also a close neighbor and a buddy. He's not the only pro I've shown my system to... and they all say the same thing; they stayed awake at night, trying to figure out how I get just four Tons of water chilling to adequately cool between 9-14kW of lighting 24/7... even when it's spiking into the nineties outside!
As much as anything else, it would be helpful for someone in the biz to actively pin down what I'm doing well, so I can be sure and replicate it.
PSUAGRO.
Well-Known Member
............well insulated? Stone house?
ttystikk
Well-Known Member
Nope. It's a standard stick built suburban home, drafty as any of them.
I think I have an idea what's going on, and if I'm right it's worth building an indoor growing consulting and design firm around it.
Indoor growing is here to stay, no matter what happens to the marijuana industry that helped birth it. This is much like the role of porn in the early development of the internet; insatiable demand for better fapping material drove the infrastructure improvements that eventually gave it the capabilities we take for granted today, like broadband, media streaming and more!
Now that indoor growing is out of the closet, so to speak, the name of the game is the same as it is in any other industry; efficiency. Do the job with less inputs; square footage, manpower, kilowatts, expensive equipment, excess consumables or what the Fuck ever saves money and delivers a better product and you can write your own ticket.
I'm writing the whole fucking ticket book, and then I'm taking my show on the road.
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ttystikk
Well-Known Member
Indoor grows can deal with water leaks. The ability to heat your home with 'waste' heat just one of a whole constellation of ideas that save money, time and/or energy.
The artificially high profit margins in pot are coming to an end, which means the entire industry is going on a cost cutting binge soon.
I plan to have plenty of cost cutting to sell them.
bicit
Well-Known Member
Seems like a lot of hvac techs either don't or can't perform the proper calculations to size and install hvac equipment.
Honestly the only reason its financially viable to grow pot indoors is due to that high margine. Once the us reschedules pot I have a feeling giant indoor warehouse operations
Will become a thing of the past. Leaving greenhouses, field growers, and a few boutique indoor ops for premium product.
The sun is hard to beat sometimes. At least until the cost of running lights is less than what's needed to run hvac equipment for a greenhouse.
Course using geothermal cooling and storage might be as advantageous.
ttystikk
Well-Known Member
You're forgetting costs and availability of land to grow on, among others. The earth is a crowded place and will continue to become more so. People will come to appreciate locally grown produce of all varieties, as much for the food security and freshness angles as for cost reasons.
The cost of indoor growing is also falling. This is my home turf, so I feel like I can speak with some authority on the subject; name any part of indoor growing and I can show you exciting innovations not yet widely installed that reduce costs in some way.
Lighting is getting better and more efficient. Same for HVAC. Since those are the two biggest power hood in the industry, I'm pretty comfortable predicting that indoor agriculture will continue to become ever more affordable and competitive. All those darkened warehouses may not end up growing weed, but they and their successors will do something even more important; keep us foolish humans alive in an ever more crowded and polluted future.
Merkin Donor
Well-Known Member
There are lots of tricks to boosting efficiency in HVAC. An easy one is to upsize the evaporator coil (FAU), for example if I'm installing a two ton (24,000 BTU) condenser I'll pair it up with a 3 ton FAU. This will give me a 30% increase in BTU's while keeping the watt draw at the 2 ton level. One Idea I'd like to try would be instead of installing one 24k/36k mini-split head unit how about 3 or 4 putting out 7,000 BTU's each. That would be a huge increase in coil area that would drastically improve de-humidification thereby decreasing the added heat load from stand alone de-humidifiers. This would also allow the room to ramp up and down depending on the size of the garden without HVAC over kill.
I can't tell you the number of times I see people drag a supply duct into a sealed room to cool it but forget about the return path. HVAC really works by removing heat and that gets us to another place for huge increases in system efficiency. The return needs to be a minimum of 2 square feet per ton on traditional split systems and btw those 15 dollar 3M pleated filters everyone buys are total shit. Imagine being forced to drink a milkshake through a coffee stir straw because that's what you do to your system when the return is too small. If you can pull your filter while the system is running and you are able to hear/feel the change then things need fixing. Supply ducts need to be properly sized for the required load and they must have the proper grills. It's not just about dumping cold/hot air into a room. It must be delivered at the right CFM and FPM to effectively remove heat/cold.
This book is the best guide out there, some things need to be modified when it comes to latent heat removal but the info will help with grow room construction and system design. It can be found in PDF version for free but for 30 bucks its worth it.
http://www.amazon.com/Measured-Home-Performance-Practices-California/dp/1582229945
The main difference for growers will be the fan speeds, for residential use in dry climates we don't need to de-humidify. Every drop of condensation here is wasted efficiency but for indoor agriculture all that is needed is to slow the fan speed down or account for stand alone de-humidification in your heat load calculations.
I can't tell you the number of times I see people drag a supply duct into a sealed room to cool it but forget about the return path. HVAC really works by removing heat and that gets us to another place for huge increases in system efficiency. The return needs to be a minimum of 2 square feet per ton on traditional split systems and btw those 15 dollar 3M pleated filters everyone buys are total shit. Imagine being forced to drink a milkshake through a coffee stir straw because that's what you do to your system when the return is too small. If you can pull your filter while the system is running and you are able to hear/feel the change then things need fixing. Supply ducts need to be properly sized for the required load and they must have the proper grills. It's not just about dumping cold/hot air into a room. It must be delivered at the right CFM and FPM to effectively remove heat/cold.
This book is the best guide out there, some things need to be modified when it comes to latent heat removal but the info will help with grow room construction and system design. It can be found in PDF version for free but for 30 bucks its worth it.
http://www.amazon.com/Measured-Home-Performance-Practices-California/dp/1582229945
The main difference for growers will be the fan speeds, for residential use in dry climates we don't need to de-humidify. Every drop of condensation here is wasted efficiency but for indoor agriculture all that is needed is to slow the fan speed down or account for stand alone de-humidification in your heat load calculations.
Merkin Donor
Well-Known Member
We do lots of hydronic furnaces here in SoCal, basically use the standing heat in your tanked hot water system to heat the home. The nice thing is that we can tailor the delivered heating BTU's by just adjusting a ball valve (just like the heater in your car). Water isn't a big deal as long as the person doing the installation is competent.