HVAC hacks for a VERY large space?
June 28, 2013 1:11 PM   Subscribe

The organization I run rents a large, old theater for once-a-week film screenings. Problem: the air conditioning is broken, and the theater doesn't have the capital to fix it before the summer ends. But we have screenings scheduled weekly through the end of August. Are there any good ways to keep a large space cool without a working AC system? (How did people keep cool in indoor spaces historically, pre-AC?)

Relevant information:

• This is in Chicago, where the weather until this week has been mostly in the 60s and 70s. Looks like it's about to get a little cooler again, too. The theater is currently still pretty comfortable.

• Our events usually have between 100 and 200 people at them, though the space itself is much bigger (~1500 seats) — one of the weird things about making use of the entertainment infrastructure of another time (the theater was built in the late 1920s).

• The theater will likely be staying closed between our screenings. So, closed 5 or 6 days a week, and open one or two evenings a week.

• Our screenings start after the sun goes down, or shortly before it does.

Here's an article with some background about the situation.
posted by bubukaba to Technology (22 answers total) 1 user marked this as a favorite
Until AC, all the Broadway theaters in New York City shut down for the entire summer.
posted by Melismata at 1:15 PM on June 28, 2013 [3 favorites]

How is the humidity? Would some kind of swamp cooler fakery work? I'm thinking a wet towel hung up behind box coolers ... not too close (electricity and water, doncha know). Probably can't do it while the theatre is occupied, though, firemarshals will have your hat.

Do the box McGyver swamp coolers the day of before occupancy, and rent/loan out personal battery fans? Include them in the price of the ticket (rental of them) maybe?

Alternatively, rent out some industrial fans and a couple of industrial portable AC units. That is a random search using renting a/c and your locale.
posted by tilde at 1:18 PM on June 28, 2013 [2 favorites]

Best answer: If you can chill and circulate water, or else you can expend cool/cold water, you can improvise an A/C by circulating the cold water in front of fans where it can absorb heat from the air.

Even without the water, the general strategy is to draw air from the cooler side of the building (North or East, in this case) and blow it out the hot air. Fans in doorways/windows, and keeping open an airpath (doors tend to shut themselves when there's a draft in place, so this must be prevented. You also have to close off as much volume as you can in order to reduce the volume you have to cool.

Start several hours (days?) ahead of time, and practice a little so you can figure out how long it takes to get the temp down. You might need to have two strategies, as far as noise-- loud before the theater opens (or before the movie starts) and quiet during.

Industrial fans are great for changing air-- they are giant propeller-shaped fans, the fans you see most of the time, but there are also compact fans which draw air from the side and blow the air out of a nozzle on the front-- it's called a squirrel-cage blower. (Think of a hamster wheel powered by a motor on the axle.) You may be able to fit the latter in a spot you can't fit or aim the former.
posted by Sunburnt at 1:24 PM on June 28, 2013

You can rent a trailered-in temporary AC system that you'd hook up through a couple of windows. I attended a movie screening at a derelict powerplant where they had one of these set up.

Important to note: it took four days to cool down the space. Which was no doubt bigger than the theater you're dealing with.
posted by adamrice at 1:24 PM on June 28, 2013 [1 favorite]

Best answer: Give everyone a paper paddle fan when they walk in the door.

Bonus: get local businesses to give you money to sponsor your club and in return, slap their logos on the fan.
posted by phunniemee at 1:26 PM on June 28, 2013 [15 favorites]

In churches in the deep south they had (have?) hand held fans, which can be ordered with your logo or maybe funeral homes still give them out (which may or may not be thematically appropriate given the films).

They might be distracting during a show, but maybe les so than dripping sweat?
posted by pointystick at 1:26 PM on June 28, 2013 [1 favorite]

Sunburnt: "You also have to close off as much volume as you can in order to reduce the volume you have to cool."

Can you hang some kind of wire or rope bordering the area you will be using, and then hang some drapes/curtains/blankets/tarps? In effect, creating a smaller theater inside your larger one.
posted by SuperSquirrel at 1:40 PM on June 28, 2013 [1 favorite]

Best answer: Does the blower still work? or did something cause the entire system to fail. Because if just the compressor/chiller is bad, i'd just set the blower to constantly be circulating air throughout the place.

A big group of people generates heat in and of itself. You want as much outside to inside, and vice versa flow-through ventilation as possible. Could you afford to pick up two of these and throw them in the fire exits? or possibly two of the cheaper, smaller ones? (this moves a great amount of air for it's size, but the drum ones are much better at directing the flow because of the drum design. It also likely achieves that high air flow through high RPM on the blades, which = a lot of noise... The drum fans are quiet, which is why i recomended them. But if you have stairs right at the fire exit and would need a stand model that one is the best bang/buck on price Vs airflow)

You want to get a serious cross-breeze going through the space if the outside temperature is at all acceptable. Best case scenario would be the HVAC systems blower(s) running to circulate the indoor air and fans bringing in cooler outside air, and exhausting hot air.

Another good question is how much does the place heat up during the day? If the answer is "not all that much until people get in it" have someone show up at say, 2am and run all the fans non stop the night before until 6-7am to blow in as much cool night and morning air as possible, then close up EVERYTHING until a bit before the showing. The goal here is to sort of "bank" cooler air for later.

I'll note that i'm no kind of expert at this, but this is the type of issue i've dealt with a lot playing shows in large houses/weird "art" spaces.
posted by emptythought at 1:47 PM on June 28, 2013 [1 favorite]

Do you have enough money to put in a mister system? That plus some big fans is enough to make outdoor patios livable in the Phoenix summer.
posted by Weeping_angel at 1:59 PM on June 28, 2013

You could make something along the lines of an Indian Water Cooler, as described here
posted by gravelshoes at 2:00 PM on June 28, 2013

Best answer: Your two basic options are to either (1) actively cool the hot air or (2) move the hot air out and have it displaced with cool air.

Air conditioners are, of course, the best version of #1 and are your best solution overall (and probably the cheapest), but let's set that aside for now.

Assuming that you have some sort of large volume of cool air that you can draw in, #2 can definitely work. If the outdoor temperature (and humidity levels) are acceptable, than just putting a bunch of big exhaust fans as high up in the building as you can and opening the doors could work. If it is too hot/humid outside, is there a big basement to this building? Could you put the exhaust fans high up and open the basement doors (and keep the street doors closed)?

The problem with #2 is that you are physically unable to get it cooler than the "sink" of air you're drawing from. I doubt there is a better/cheaper version of #1 that's likely to work than just fixing the A/C.
posted by Betelgeuse at 2:16 PM on June 28, 2013 [1 favorite]

If this is in Chicago and will be running through August, I don't think any of the evaporative (e.g. swamp cooler, Indian Water Cooler, mister, etc) options are going to be sufficient.

These systems require low humidity in order to work, which is why they work so well in (for example) Phoenix. Unfortunately, when it is warm enough in Chicago to need cooling, it is usually too humid for an evaporative system to help much.
posted by Juffo-Wup at 2:41 PM on June 28, 2013 [3 favorites]

When we were looking at getting married at Ida Noyes hall (the U of C student union, essentially), we were quoted $5k upfront to rent an external air conditioner, and that they'd split the cost with other events using the space during the week to bring it down.

From this I learned 1) renting air conditioning is expensive and 2) you can defray the cost if you split it with another group?
posted by Oktober at 2:52 PM on June 28, 2013

Best answer: Desert cultures have used windcatchers to cause airflow; if the building is a 1920s theatre, there's probably flyspace behind the screen -- open vents at the highest point, leave the front-of-house doors open, and you might get enough of a draft to keep the area comfortable. Making it "cool", probably not -- but comfortable might be possible.
posted by AzraelBrown at 2:54 PM on June 28, 2013

Large blocks of ice in front of large fans.
posted by JohnnyGunn at 4:07 PM on June 28, 2013

Best answer: Large blocks of ice and misters and whatnot won't do anything, especially in a room that size. Maybe in the desert, but not in Chicago summer, which is practically tropical.

All you can do is encourage ventilation. Open the doors/windows on the north side of the building and suck air out of the other side of the building.
posted by gjc at 4:11 PM on June 28, 2013 [2 favorites]

If you're going to not have A/C, for goodness sake TELL people about it ahead of time, even if it negatively impacts your attendance. I would be pissed beyond belief to arrive anywhere other than a campground in 2013 and not find air conditioning. (I may veer into complete irrationality about this, but I really, really hate being hot.)
posted by Sweetie Darling at 8:03 PM on June 28, 2013 [6 favorites]

Best answer: Hot air rises. If you can open vents, roof hatch, anything at the top of the space, and open doors near the bottom of the space, you can get rid of the hottest air, and even get some air moving.
posted by theora55 at 8:27 PM on June 28, 2013 [1 favorite]

You might want to research this a little more deeply. I believe there are codes for assembly spaces that may pertain to air changeovers -- so many complete changes/hour, for example. Also, rigging up a lot of equipment to do what you're doing opens up the potential to have electrical issues not to mention additional fire hazards. Blocking exits with fans is problematic and you'll run afoul of the fire marshal and may face fines, not to mention it is an actual safety hazard.

Fans and blowers are loud. They would likely disturb a showing. Your best bet is to try to cool the space well before. And offer fans and you could do a big trough of iced-down bandanas for people to take if they get overheated. Tell them to dress for the heat and make sure you have people stationed at exits to help anyone who needs to get fresh air.
posted by amanda at 8:44 PM on June 28, 2013

Best answer: How did people keep cool in indoor spaces historically, pre-AC?

The old main hall of my parents' church in Washington DC had little shelves mounted up on the walls about every 15 feet, each for supporting an oscillating fan. Plus the hand fans (devorated with scripture) mentioned above were distributed.
posted by Rash at 2:28 AM on June 29, 2013

If I were in your situation, and dealing with only 100-200 people, I would find another venue. (especially with the new blow up screens which makes nearly every room into a theater space, well, sort of).

If you count on repeat customers, having them suffer through a screening in an overheated space will assure that they won't come back.
posted by HuronBob at 3:33 AM on June 29, 2013 [1 favorite]

Unless you can find someone to donate, forget the rental. If you're showing once a week you'll have to rent it for the entire rest of the summer - at least in my market that would be too expensive. You also have to find somewhere to put it... although if the building has a chilled water loop you have more options, it's easier to pipe cool water than it is to pipe cool air.

What exactly is broken in the A/C system? Assuming it's the mechanical cooling, and not the air handling system, this would be my suggestion (assuming a typical system)

Forget about ice or misters. Your humidity profile isn't applicable, and jury rigging something like that may damage the building.

Ignoring building and lighting loads, the A/C load for that many people is only in the 4-6 ton range. The air handling system in the building is going to be sized to handle 40 tons of people load plus the building load. Run the blower, manually open the outdoor air dampers and just keep exchanging the air. Make sure both the outdoor air filters and the indoor air filters are clean. You may get away with "free cooling" by air exchange because you're not anywhere near capacity.

Turn off whatever lighting you can. Turn off all lights or other sources of heat until right before the shows. You want as large a buffer as possible before people notice the temperature rise, so keep the building as cool as possible, then at show time fire up the projectors, lights, and hopefully the large venue will take long enough to warm the show will be over before it's unbearable.

Did you also lose A/C to the projection booth? That may be a bigger issue. Blowing up a projector isn't cheap.
posted by vonliebig at 7:00 AM on June 29, 2013 [2 favorites]

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