Hell yeah it’s an HVAC post

Mobile Hospital Assembly

Volunteers assemble a mobile hospital unit in Mississippi, 2014. NARA ARC ID 24484111.

Consider this a desperate appeal to you, Dear Reader, to direct me to the contemporary resources which must exist already describing how actually-existing archives run their HVAC systems, and what that means for our carbon footprint, and thus whether — when we install newer, more efficient systems — we’re kind of just fiddling with marginal fixes in the face of imminent global catastrophe. Because by Allah (pbuh) I cannot find those resources.

Here is the thing. The world agrees™ that in order to arrest the slow decline through absorption of water vapor of (still mostly paper) archives, storage environments should approach 60°F and between 35% and 50% RH. The shield between the collections and the steadily warming external air is our HVAC systems. Anecdotally, I’ve watched some routine failures of HVAC over the past five years in particular, and it seems obvious that the next few years are going to put these systems in chronic distress.

I’ll tell a story: while 2018 wasn’t a notably hot summer where I’m from, it was extremely wet all year, and in order to get humidity down in the building, we ran a savage burn on our air-chilling systems, which responded by breaking. Since, like a lot of mid-century buildings, ours has no way of getting outside ventilation, i.e. opening a window, when our chillers failed we got to 90° indoors in a hurry. Water vapor condensed on the floor. This happened twice.

What does baseline operation for an archives HVAC look like? How do systems contort themselves to confront a rapidly-changing external climate in order to maintain an entirely uniform internal climate? Do you know? I have no idea. Our partners in the industry insist that every institution is unique and requires bespoke designs, which sure, okay, we probably did that to ourselves, and I’ll save a bespoke rant against archives smallholders for another time. But there have to be common qualities. Let’s just by way of randomly plucking an example from thin air, try and learn something about easily my favorite building, oh lawd he comin


Yale’s Beinecke Library, the absolute unit, has a square footage of  88,347.  According to this 2012 Energy Information Administration survey of buildings’ energy use, the average American building consumed 82,000 btu of  energy per square foot. Take a look at the breakout by building use, and you’ll see the average is a little tamped down by warehouses and other mostly-vacant buildings, like churches.

And so you’ll also note that archives and libraries probably don’t have the energy usage of a normal office space (77,000 btu/sq.ft). Given our needs — 60 degrees, low humidity — and the fact that we can’t just shut the units down when there aren’t people in the building, we’re somewhere between malls (100,000 btus/sq.ft) and grocery stores (200,000 btus/sq.ft). Now there aren’t a lot of us with large frozen foods sections, except for you guys who keep your general circulating library collections at 40 degrees, which is a story I heard about a place. So let’s take the high end.

88,000 feet by 200,000 btus is 17,600,000,000 or to sound it out, Seventeen billion six hundred million British thermal units used in a year.  So what are we burning to get those tasty btus, and how much carbon does it give off? Coal gives us 200 pounds of CO2 per million btus; natural gas, half that; sweet propane, 139. Not all energy mixtures are the same, of course. Connecticut gets about 2/3s of its electricity from nuclear plants, and the other 1/3 from natural gas. So electricity for the Beinecke HVAC and lights and stuff has a carbon cost of probably 66 pounds per million btus. 66 times 17,600 gives us 1,161,600 pounds of CO2 per year. To help visualize that, it’s emissions equivalent to 1.2 million miles driven by the average car, or 21 thousand canisters of propane, sweet propane.


Yet another way to visualize this footprint is that for the same amount of carbon you could send about 1000 people from Yale to SAA2019 in Austin.


Having a building that emits about 120 cars’, or 63 houses’ worth of carbon seems like not a terrible exchange for maintaining access to the cool shit in the Beinecke. But New Haven’s number of cooling-hours per year is going to start to resemble Charlotte’s real soon, it’s not like the required energy to run the building is going to shrink. The share of energy we get from fossils might change. Just as over the past decade, electricity producers have pivoted from coal to natural gas, we’ll see a pivot from gas to atoms, probably not nearly fast enough to keep us under 2 degrees C.

I want to know more about the maintenance of archives HVAC systems, I want to hear the horror stories, but more than that I want to sit for a while with the thought that we’re trying to create environments where materials in storage degrade only over a 500-year time frame, which is madness and vanity, given that the society we’ve come to know and love barely has 30 years left of its own.

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