3 phase inverter recommendations

[Gilligan]

Ok, so let's address the elephant(s) in the room.

First, building insulation:

It's a metal building that is pretty old with a drop ceiling at 8'. There are some standard batting type insulation laid on top of the tiles and most of the insulation "sheets" under the roof are failing. Most of the heat comes radiating from the metal roof that gets too hot to touch. One thought is that solar panels of the magnitude I would need 60-80 would essentially shade the roof. I've done some experimenting and ran a soaker hose along the roof and it did help cool down the "attic" space significantly which helped... but the water bill increased about as much as the electric bill went down. The other source of loss is that the building is SUPER drafty. There is about a 8"-10" cavity on the north side of the building that has zero insulation. When the wind blows hard it will open the doors of the place (we have remote "bells" that chime when the doors are open as we are not always up front and they go off a lot when it's windy out). This is partially because the "attic space" is vented so pressure can get in there and come through the drop ceiling. Also, there are PLENTY of leaky areas all around. I'm not sure they are all sealable but I guess a case of great stuff could go a ways into trying to fix some of that... but again... a drop ceiling (of this age) isn't going to ever be airtight and that roof will always be vented (by design).

Cost of "upgrading insulation": I've had a few spray insulation companies come and look at it and when I was only 1,600 sqft it was going to be $4k min to spray expanding foam under the roof. Now I have another 800 sqft more that I occupy, so I imagine it would be around 6k to spray insulate all of this. To what magnitude would this really save us over shading the roof with the panels as a bonus to the panels themselves? $6k buys about 30 panels, that would cover a good 30% (Maybe more but I don't want to oversell it). Plus that doesn't change the fact that the building will still be drafty as hell... just hopefully the attic air would be 120* vs 150* (but shading would help with that as well).

All of the active heat sources in the building:

Ok... so this is just a fact of life in a screen printing shop. I have the giant conveyor dryer that is about 12,000 watts of infrared heat panels running at about 80-90% duty cycle maintaining an internal panel temp just shy of 1,000*F, this unit is vented to outside, but there are still shirts that reach min. 320* that roll out of the heat tunnel and are "off-gassing" all of that heat into the space. There ARE options of trying to capture that heat just as it comes out of the dryer and exhausting it out of the building with like an oven vent hood style of system... these are all basically DIY setups I have seen. The ceiling above the output of the dryer where these shirts come off is about 150* with the IR gun. IF I had unlimited space then there would be POSSIBLY an option of having the dryer or at least the output live in a space that isn't climate controlled (I know of like 2 shops out of a 100 that I am very familiar with that do this... it's not very common). But at the end of the day... I have 2400 sqft of space and I just simply can NOT remove the dryer from the climate controlled space. This is a very impractical task as the shirts come off of a piece of machinery and are hand loaded onto the belt that immediately goes into that tunnel of heat. It's a fact of life in a screen printing shop.

There is also a 4,000 watt quartz bulb unit that stays on during some jobs for "flashing" (if anyone is familiar with screen printing). This has 4 small squirrel cage fans that blow this air away immediately (part of it's magic actually) so this heat is radiated and spread around the room and there is ABSOLUTELY zero way of removing this source of heat from the climate controlled space. We actually want a 2nd unit and if I had the electrical resources I would seriously be looking at adding a 2nd unit... but my panels is pretty much maxed out.

Then there are two heat presses for vinyl and DTG (for those familiar with this world). They are about 1,800 watts of infrared radiating heat panels that maintain 330-350*F temperature. They aren't always on, but if our business continues to grow they essentially would be on more and more. Again, this is IMPOSSIBLE to remove from the climate controlled space.

I also have a dehumidifier that lives inside a "drying cabinet" that generates a good 100* of heat in that box which obviously leaks out as we not only use it but it's just not sealed and honestly probably couldn't be because then it might get too hot in there.

So... there it is... why I can't fix the heat sources and then the pros and cons of trying to fix the insulation issue.

I'm all ears at what I'm overlooking but as far as "remove the heat sources" that's not practical/possible. I do agree fixing the insulation would be ideal... but I wonder if the panels shading the roof wouldn't be nearly as effective while adding power at the same time. My estimations are that 30 panels (the cost of insulating) would create about $150/month in electricity. Insulating MIGHT yield similar results and then again might not.

Here is part of the issue with "insulating"... right now the AC runs constant and doesn't keep up. I know this sounds like a no brainer "yea, because you aren't insulated"... but the temperature inside goes from 72-73 in the morning to 84* by end of the day. So if I insulated and the temp was able to actually come down to reach 75* it's entirely possible that it would still need to run the AC constantly to do so. This would give us comfort... but a comfort with ZERO gain in energy savings. So the ROI to fixing the insulation could potentially be just comfort for us. Whereas the panels would improve efficiency by adding shade on the roof as well as generating power which would of course absolutely offset my energy cost.

Does that make sense? I'm not looking for an "amen", I'm honestly wanting people to blow holes in my plan... I just need everyone to understand all the details and facts for their holes to make sense.

Thanks for all of your time and sorry for the long detailed post.

[Mike90250]

More detail is better. So at least you are spending $$ with your eyes open. I guess you can hunt around on the web and see what shading the roof does for heat gain, I have no numbers for it.
What about putting power exhaust vents in the roof, with a hood above the big heat producers ? as long as the building is "leaky" suck the heat out and not try to chill that air back down.

How about painting the roof a light reflecting color (not the "ceramic thermal paint" rip off)

So you have our advice, and you know your budget & building.

[Gilligan]

More detail is better. So at least you are spending $$ with your eyes open. I guess you can hunt around on the web and see what shading the roof does for heat gain, I have no numbers for it.
What about putting power exhaust vents in the roof, with a hood above the big heat producers ? as long as the building is "leaky" suck the heat out and not try to chill that air back down.

How about painting the roof a light reflecting color (not the "ceramic thermal paint" rip off)

So you have our advice, and you know your budget & building.

Thanks,

I know soaking the roof with water reduced the attic temps by like 30*. I ran a temp sensor up there and it was like 150* and ended at about 120* when the water was evaporating the heat off the roof. I know that's different than shading, but I could take some samples from cloudy days vs sunny days and that might be a better "Tale of the tape" for apples to apples. Though the day wouldn't be as hot of a day either that could be essentially factored in as well as a 88* day vs a 92* day probably isn't a make/break difference vs the hot sun beating down on that metal roof.

BTW, the roof is a silver/white (can't recall exactly) roof... so it is fairly reflective but definitely not as reflective as a "cool seal" product. So that might be a good/cheap first step. There are a few leaks along the seams (probably rubber grommets that have dried up on the screws) that leak during hard rains and this might also help seal that up.

I will likely look at building a hood for the exit of the tunnel, the cabinet of the tunnel really isn't that hot (it's insulated fairly well... It's the Cadillac of electric (vs gas) dryers for the industry.) We regularly put our drinks and phones on top of the dryer while printing and never worry about them getting hot, though it is warm. But that exit with the hot shirts coming out of the tunnel does expel a good deal of heat. The belt is almost too hot to touch and is too hot to touch on the solid edges. Whereas when it comes back around to the other side (after passing underneath) it's not too hot to touch anymore. Trying to capture and exhaust that heat would be beneficial.

I need to find someone that knows about venting attic spaces and get their opinion on what would be the best method of cycling the air up there. I need to make sure I'm pulling air from outside to replace what is up there now vs pulling air from inside. Hate to be pulling in 90+ degree humid air in constantly while sucking our AC out.

[bcroe]

As was pointed out, your hot processes need to be power vented directly out. No
point in keeping the exhaust air if it is hotter than outside temps. Your AC practically
will not be able to deal with that heat. Insulation matters, but I suspect it is a secondary
issue for your situation (with the AC not keeping up). I have poor insulation, but my
energy efficient AC can keep up.

Realize that the cost of solar panels might be only a quarter of a complete operating
PV solar system. I spend more on the supports than the panels. Normal practice is to
tilt up panels to be roughly perpendicular to sun energy, for best efficiency. But that
does require a lot of spacing between rows to avoid shadowing each other. But if
placed flat all in one plane the roof would be well shadowed, at a loss of individual
panel production, but the total roof area production would be considerably increased.
This would also increase output under clouds. Another downside to this is difficult
access for service, and venting air over the roof.

As for AC check the SEER or COP of your equipment. I just replaced my typical 2014
unit with new high tech (mini split variable speed inverter drive compressor). The
result is better performance while saving more than 50% on electricity. There may be
a good fit for your application, once the heat is vented out. At that stage panels may
be able to deal with the electric load. good luck, Bruce Roe

[Gilligan]

As was pointed out, your hot processes need to be power vented directly out. No
point in keeping the exhaust air if it is hotter than outside temps. Your AC practically
will not be able to deal with that heat. Insulation matters, but I suspect it is a secondary
issue for your situation (with the AC not keeping up). I have poor insulation, but my
energy efficient AC can keep up.

Realize that the cost of solar panels might be only a quarter of a complete operating
PV solar system. I spend more on the supports than the panels. Normal practice is to
tilt up panels to be roughly perpendicular to sun energy, for best efficiency. But that
does require a lot of spacing between rows to avoid shadowing each other. But if
placed flat all in one plane the roof would be well shadowed, at a loss of individual
panel production, but the total roof area production would be considerably increased.
This would also increase output under clouds. Another downside to this is difficult
access for service, and venting air over the roof.

As for AC check the SEER or COP of your equipment. I just replaced my typical 2014
unit with new high tech (mini split variable speed inverter drive compressor). The
result is better performance while saving more than 50% on electricity. There may be
a good fit for your application, once the heat is vented out. At that stage panels may
be able to deal with the electric load. good luck, Bruce Roe

Thanks... I've thought about different angles. I'll probably try to angle it and use the shadow throw to better shade the full roof during the summer with less panels.

My outside compressor is fairly new as it just failed recently and had to be replaced, but probably not as efficient as it could be. It is 3 phase so it's a bit more efficient than a standard single phase.

One of my employees/friends is an AC guy so he maintains all my equipment and advises me when we should replace and such. I'll discuss this information with him and weigh the pros and cons.