the house with a mainframe in its walls

March 26, 2019 9:24 AM

Is This Harvard Prototype the Greenest House in America? HouseZero, the headquarters for the Center For Green Building And Cities was extensively retrofitted by Snøhetta and Skanska Teknikk, even to the point of having no HVAC system. The Brain in The Basement controls temperature and ventilation.
posted by the man of twists and turns (19 comments total)

Pretty sure this was originally a Ray Bradbury story that got folded into The Martian Chronicles.
posted by Naberius at 10:11 AM on March 26, 2019 [3 favorites]

Which was then made into a story about Metafilter.
posted by Melismata at 10:17 AM on March 26, 2019 [1 favorite]

No fans? Unless there's a constant breeze I would not be very productive while awake, not sleep at night and go mad pretty quickly.

I also wonder how comfortable a building with no HVAC could be where the summer highs are in the 90s or triple digits, not 82. I'm not knocking this, just saying that different climates are likely to need different solutions.
posted by Foosnark at 10:49 AM on March 26, 2019

I've always been fascinated by zero-energy / passively heated buildings. A place I worked had a building with a Trombe wall left from a 1970s green-building initiative, although I was never able to tell if it added much heat during the winter or not. But it always seemed neat.

I like that they've moved away from the idea of hermetically-sealed windows, though:

Well aware of variances in personal preference (a.k.a office temperature wars), and skittishness about the notion of a fully-automated building, architects designed manually operated parts too. “The building itself will strive for best possible comfort, however, a window can always be opened manually to ensure individual comfort still remains firmly tethered to human instinct,” he writes.

Although this does make me wonder how they handle the "V" part of HVAC in the winter. I don't doubt that you can make a passive solar house even in a northern latitude with enough insulation; the sun, after all, puts out more than 1kW per square meter... but what happens when someone takes a giant shit in the bathroom and wants to run a ventilation fan? Or someone decides to sauté five pounds of yellow onions in the kitchen? A good kitchen range hood—which you want, if you care about indoor air quality—for a 30" wide stove will pull 250-300 CFM; so if your onions take 15 minutes to cook, that's 4500 cubic feet of warm air that's gone, and an equivalent amount of cold outside air that's been pulled in (whether through a dedicated air intake or just through gaps in the envelope, or by creating a static pressure difference that'll be resolved when someone opens a door and lets in the mother of all drafts). I've never seen an air-air heat exchanger / heat recovery unit sized for something like a bathroom fan or kitchen vent, although that's presumably what you'd want. I wonder what they're using.
posted by Kadin2048 at 11:22 AM on March 26, 2019 [2 favorites]

I suspect that the answer is that it comes with a large asterisk due to questions like that Kadin2048.

I lived in the Texas Panhandle for a while and worked with people involved in low energy climate control and it never worked at zero energy unless no one was actually using the building. Added insulation, trombe walls, solar chimney, they're all darn good and should be used more often, but especially in more extreme climates they're going to be insufficient especially once you get people living there.

Heating passively is always easier than cooling passively, so it doesn't surprise me that we're seeing a lot of the people evangelizing on this coming from climates that have mild summers and only fairly chilly winters. Like those found near Harvard....

In a humid, hot, climate most of the really effective low/zero energy approaches to cooling simply don't work, as your best bet for passive cooling is evaporation and in a sufficiently humid environment that stops cooling hardly at all.

Up in the Texas Panhandle we could cool fairly effectively with evaporation, though it wasn't really zero energy as it cost energy to get the water and to move it through the evaporative systems. Where I live now, in San Antonio, the air is so humid during most summer days that evaporative cooling doesn't really work at all.

Passive solar heating really should be more of a priority for places where cold weather is the main concern, if for no other reason than it's dead simple and cheap. The simplest design, 100% passive no energy required, is basically just a long box painted black on the inside with a glass or plastic top and one end stuck into a window. My father made a couple when I was a kid for about $30 each and they worked shockingly well, even on a colder winter day they'd be cranking out pleasantly warm air. You could easily reduce the heating bill for single dwelling homes in the northern parts of the country with passive solar heating.
posted by sotonohito at 11:42 AM on March 26, 2019 [2 favorites]

"but what happens when someone takes a giant shit in the bathroom and wants to run a ventilation fan?"

I envision a sleek robotic arm emerging from the bathroom wall holding a big strike-anywhere match.
posted by Hairy Lobster at 12:30 PM on March 26, 2019 [4 favorites]

Air exchange and humidity control are the two keys to building g healthy, comfortable spaces. As others have noted, heating is less of a challenge than cooling. Passive House homes are so well insulated that you need to consider the heat put off by the refrigerator, lights and expected occupant counts to accurately calculate heating loads. Theoretically, you can build a home that can be heated with a hair dryer for even the coldest days.

The need to breathe clean air complicates the equation. People respirate CO2 and H2O, not to mention off-gassing from plastics, cooking fumes, humidity from bathing, etc. This means systems are neeeded for exchanging and tempering outside air. Typical ERV (energy recovery ventilators) and HRV (heat recovery ventilators) systems can do a pretty good job — to a point. As mentioned above a good range hood pushes the limits of typical residential ERVs and a high-end 600-1000cfm hood for a fancy commercial-style cooktop will totally overwhelm it.
posted by Big Al 8000 at 1:12 PM on March 26, 2019 [3 favorites]

Also, the most efficient HVAC system is the one you don’t build. Modern homes are entirely too big.
posted by Big Al 8000 at 1:13 PM on March 26, 2019 [1 favorite]

People have lived for hundreds of thousands of years in many different climates without HVAC, by actually designing homes suited to their climates.
posted by signal at 5:21 PM on March 26, 2019

signal While that's true, it's also true that the more heavily populated parts of the world have always been more temperate and the population in the really horribly hot or cold parts of the world has tended to be fairly low.

Also, just about everyone embraced air conditioning the very instant it was possible because while you **CAN** live through a horribly hot and muggy summer without it, you don't really want to.

Naturally we should work to make our housing match the climate as much as possible. I'm absolutely in favor of thicker walls, more insulation, green roofing, whitening roads, and so on. But I think people will still want a bit of AC in the hot climates even with all that.

I live in San Antonio these days, and while it's not exactly tropical down here, it's pretty damn oppressive in the summer, and every year people, mostly older people and homeless people, die of heat exhaustion in the summer. I think unless people have actually experienced a real hot southern American summer its difficult for them to grasp just how bad it really is.

And there's places that climate change may well render totally uninhabitable. It really is true that it's not so much the heat as the humidity. A person in shade in a low humidity environment can survive (if not be so happy) in temperatures up into the 40's.

But even temperatures **BELOW** human blood temperature can be deadly if there's enough humidity. A sustained wet bulb temperature of 35 or above will kill a healthy person sitting in shade next to a fan. Without the cooling effect of sweat evaporating your body just can't dump heat fast enough.

Right now we're looking at sustained wet bulb temperatures in the low thirties becoming increasingly common in the more tropical regions thanks to global warming. Wet bulb temperatures up to 35 are still fairly rare, but you're not going to want to live in a place with even a wet bulb temperature of 30 or so without some sort of air conditioning, it's difficult to overstate just how bad that is.

Better building will help a lot with that, but just by itself better building won't help enough.
posted by sotonohito at 5:40 PM on March 26, 2019 [5 favorites]

Kadin2048: " I've never seen an air-air heat exchanger / heat recovery unit sized for something like a bathroom fan or kitchen vent"

It's pretty common in Canada for an HRV to provide bathroom ventilation.

Of course usually when you are running a hood fan you are also running a big heat source.

signal: "People have lived for hundreds of thousands of years in many different climates without HVAC, by actually designing homes suited to their climates."

The American south west was basically unpopulated until the advent of mechanical air conditioning.

And people used to tolerate more variation in their indoor temperature. And of course people used to freeze to death/bake to death on a regular basis too. See for example any place without air conditioning that experiences a heat wave.

There is also some evidence that excessive heat during sleeping hours in the long term lowers intellectual/academic performance.
posted by Mitheral at 9:29 PM on March 26, 2019

The American south west was basically unpopulated until the advent of mechanical air conditioning.

It really depends on what you are considering the southwest, but Dallas and Houston (both heavy A/C cities) had significant populations prior to the advent of air conditioning. New Orleans was the 12th most populous city in the US in 1900. If you specifically mean Arizona & Colorado, I mean northern Arizona and parts of Colorado have some of the most temperate weather in the continental United States, so bad on the people of 1700-1900s for settling in extreme weather environments like Maine and Vermont.

Also, the cradle of civilization is Africa and the middle east, which has extreme weather and humidity, so I'm not sure I agree that people generally have settled in temperate environments, except unless you are only talking about Europeans. Unfortunately for us, extreme weather means water and lifeforms, moreso than temperate weather does.

Finally, I think humidity and really A/C should be easy to net zero as the sun is typically shining and therefore solar can be great solution and the water pulled from the air can be put to useful purposes. Right now, it's required to be sent down the drain on central A/C systems.
posted by The_Vegetables at 7:27 AM on March 27, 2019

I was meaning declining population trends reversed themselves in the south as home A/C became affordable. Las Vegas or Phoenix as examples would be a bump in the road rather than massive metropolises they currently are without mechanical A/C but they are just extreme examples of a population shift.

Many of the central changes in our society since World War II would not have been possible were air conditioning not keeping our homes and workplaces cool. Florida, Southern California, Texas, Arizona, Georgia, and New Mexico all experienced above-average growth during the latter half of the 20th century—hard to imagine without air conditioning. In fact, the Sunbelt's share of the nation's populations exploded from 28 percent in 1950 to 40 percent in 2000.

Solar power A/C and dehumidification has the same storage problem as anything strictly solar powered. The environment continues to be hot and humid way after the sun goes down.
posted by Mitheral at 9:14 AM on March 27, 2019 [2 favorites]

Solar power A/C and dehumidification has the same storage problem as anything strictly solar powered. The environment continues to be hot and humid way after the sun goes down.

So what is my answer. This post is about technological innovations that keep the cold of Boston acceptable at bay via insulation and other modern and advanced techniques, some passive and some active. The windows in this house even open and close automatically. I don't see how solar, either storage or generation, are any different than cold which generally increases as the sun goes down. And sure the weather in Phoenix sucks, but so does the weather in Buffalo NY and points north. Even in Phoenix, the badness of the weather is overstated. It's perfectly livable 7 months a year. The lack of local water is a much bigger deal than the heat.
posted by The_Vegetables at 9:51 AM on March 27, 2019

Mitheral: "The American south west was basically unpopulated until the advent of mechanical air conditioning.
"

I'm well aware that air conditioning has been embraced by people in the US, which allows them to build air conditioned boxes that completely ignore the climate they're dropped into, and that this is part of the reason why the US wastes such a large proportion of the world's energy.
I also know that the vast majority of humanity lives without air conditioning, even in harsher climates than any found in the US, and manages to survive.
posted by signal at 7:02 PM on March 27, 2019

signal I'm not sure I understand what you're advocating for here. Are you urging that the US depopulate large portions of the country? Are you advocating that people living in the hotter climates need to just stop using AC and get used to being hot and miserable?

The_Vegetables Heating is much simpler and less energy intensive than cooling, basically because entropy. You can heat a place almost by accident because heat is the waste product of a huge number of processes. Good insulation will make the energy needed for heating minimal.

Cooling, by comparison, is a vastly more complex and energy intensive process, that's why we didn't have any practical means of making things cold ourselves until 1834, while we've been heating our environment since we discovered fire. Until then we'd been limited to taking cold from naturally occurring cold places, storing it, and moving it around (also at great expense I might add).

As for Phoenix, it's one of the easier places to cool because it's a dry climate. It tends to get cool at night almost every night, and evaporative cooling works quite well there. As I noted earlier, it's the places that are both hot **AND** humid that are the real problem.

Humans can survive temperatures into the 40's, provided they stay in the shade and have enough water. They might not be very comfortable, but they can do it. But if you get very humid environments even temperatures as low as 35, two degrees below blood temperature, can be deadly, and temperatures in the low 30's will be extremely uncomfortable. Again, it's evaporation. If your sweat can evaporate it'll cool you and keep you alive, if it can't that's when you run into serious problems.

In Phoenix the nights are usually fairly cool even in the summers because it's a desert climate and that low humidity air doesn't hold heat. Look at New Orleans, or Houston, for examples of the much more difficult to cool and live places.

And that's the answer to your question. Heating is, relatively speaking, easy and energy cheap. Cooling is, relatively speaking, much more difficult and energy expensive. If you're dealing with a place that's relatively low humidity techniques using evaporation (trobe walls, evaporative coolers, etc) can substitute access to fresh water for energy.

But even an earthship type house, with nearly meter thick walls and half buried, will still require more energy to keep cool in New Orleans or Houston than a much less insulated home in Boston will need to keep warm.

Anyone with some spare lumber, a bit of plastic, and access to black paint can build a passive solar heater that will be darn effective even on the coldest Boston days. There is no equivalently cheap and low energy solution for cooling in Houston. Cooling, especially in humid environments, is just plain more energy expensive and complex.
posted by sotonohito at 5:55 AM on March 28, 2019 [1 favorite]

sotonohito: "signal I'm not sure I understand what you're advocating for here. Are you urging that the US depopulate large portions of the country? Are you advocating that people living in the hotter climates need to just stop using AC and get used to being hot and miserable? "

I'm not advocating anything. I don't see any ambiguity in what I posted that needs explaining.
I might be a tad bitter that my son and grandkids will spend their lives in a budget Michael Bay dystopia in part because some first worlders really like AC, but that's just my global-south bitterness seeping through.
posted by signal at 6:34 AM on March 28, 2019 [1 favorite]

I don't understand, perhaps if you'd spend a bit of time expanding I could understand.

Is it your contention that the roughly 12% of total energy consumption in the US going to air conditioning is responsible for bad economic conditions in the global south? That the 12% extra electricity used in America on air conditioning is especially egregious or irresponsible carbon use?

I also note that the global south uses air conditioning when and as the people can, because living in hot climates without AC is pretty miserable. In Afghanistan and Iraq air conditioning is used as much as the people in those areas can afford it when the power is on.

In fact, air conditioning use is expanding all over the global south, not as quickly as the people there would like, but it's hardly as if there's any moral reason they don't use AC. The only thing holding back AC there is poverty not any sort of noble and principled refusal of AC. And, speaking as a bleeding heart liberal, I'm entirely in favor of that.

We need to address climate change in a manner that is effective **AND** doesn't require us to live in misery.
posted by sotonohito at 8:12 AM on March 28, 2019

Right now, it's required to be sent down the drain on central A/C systems.

Well, it's not really required; I mean anyone with a central AC system can probably go down to the evaporator (thing that sits on top of the furnace) and locate the condensate pump. In fact I'd urge anyone with central air conditioning to ensure they know where it is, because when the thing breaks... your basement can flood surprisingly quickly just from the condensate water. (This is empirical, not theoretical, knowledge.)

Most places that I've lived in actually have the condensate drain line routed outside, spilling onto the ground somewhere in the vicinity of the compressor/condenser. This may simply because it's easier/lazier than getting to an actual drain, or maybe it's a code thing, I'm not sure.

Anyway: it's certainly not hard to take that drain line and run it somewhere else, if you want to do something with the water. Generally it's just 1/4" or 3/8" vinyl tubing, which you can easily find at Home Depot. You need to make sure not to overstress the condensate pump with too much vertical lift, but if you have a rain barrel or something (or wanted to make one), it probably wouldn't be hard to run it into the barrel and then use the water for garden irrigation. Or you could use it for swimming pool top-off water or something, if you have a pool.

This page says you can get between 5 and 20 gallons per day of water from a typical home central AC system, and it should be treated like distilled water in terms of its lack of minerals, but also used like rainwater (i.e. not potable) because of the chance of metal contamination. Personally I'm skeptical about the heavy-metal contamination issue, but I think it'd be a bit nasty to drink due to the mold that tends to grow in condensate lines. YMMV though.
posted by Kadin2048 at 2:55 PM on March 28, 2019 [1 favorite]