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Eastgate Centre, Harare (wikipedia.org)
201 points by zeristor on July 13, 2019 | hide | past | favorite | 61 comments

I was in Cairo a few years ago and in the old Islamic city there was a couple of big mosques. This dates back to the Islamic era (around 1359). Standing in the venue that separate the two mosques. Here is the location: https://goo.gl/maps/ibwqwb33PcUJvm1K7

It was in the Summer and Cairo was boiling hot. But interestingly the venue was pretty cool. There was two factors: The mosques shadowed each other in a way that you don't get exposed in the sun. Another factor, there was a cool air flow coming from somewhere(?). My guess would be that the two buildings where engineered to both protect from the sun and generate the airflow.

You can sit in the venue all day long and not be annoyed with the hot weather. The buildings themselves where pretty cool inside.

I think the question is: Why are we so inefficient today? It's not about looks either: We are building even uglier buildings. The building I'm living in right now is buzzing with air-conditioning units. It's wasteful and it's also an inferior solution (headaches, dry air, only inside is cool, etc...)

> I think the question is: Why are we so inefficient today? It's not about looks either: We are building even uglier buildings. The building I'm living in right now is buzzing with air-conditioning units. It's wasteful and it's also an inferior solution (headaches, dry air, only inside is cool, etc...)

I'd guess because of misguided "separation of concerns" and the ability to externalize the inefficiencies: You can either carefully analyze the surrounding climate and the usage patterns of your building, then hire architects who are able to take those into account and are willing to work with the imposed constraints - or you can have your architects go wild and imagine whatever crazy shape you want and treat climate control as an afterthought: After all, you can just slap on some air-conditioning and be done.

Of course air-conditioning will cause numerous problems: Energy usage, air pollution, additional heating of the outside environment, etc - however as long as energy is cheap, those are not the problems of the owners of the building.

https://en.wikipedia.org/wiki/Windcatcher and others

Passive cooling techniques are quite advanced in middle eastern tradition of architecture.

Windcatchers can also be used in combination with qantas to provide more cooling capacity.

A qanat or kariz is a gently sloping underground channel to transport water from an aquifer or water well to surface for irrigation and drinking, acting as an underground aqueduct.

Qanats used in conjunction with a wind tower can provide cooling as well as a water supply.


There are lots of ways to cool large spaces passively if the air is hot and dry. Your options are much more limited if the air is hot and humid. That's why most of these innovations come from places with arid climates such as Egypt, Zimbabwe, and (parts of) California, and practically none from Japan or Singapore.

What can they do in those situations I wonder?

>Why are we so inefficient today?

We tend to one of a few extremes: a few buildings (often for show) are ultra-green and usually stuffy, others are meticulously space-optimized to maximize residency, and still others are vehemently individualist, a project (usually a house) built on a plot of land as though it were the only plot of land in the Universe. Projects in the last two categories tend to sacrifice energy efficiency because it is too expensive, in the one case because it reduces units per square inch and in the other because owner-built SFH usually optimize for a very idiosyncratic comfort/price ratio.

In the old days, construction was often managed by the army (viz. nobility), and designed at a town scale. Today, as part of a reaction to the crushing inhumanity of feudalism, we silo off our construction projects to preserve our individuality, or we "build by any means necessary" to make optimal use of what little space we haven't yet wasted. A compromise might eventually be reached.

In particular, a lot of old-school heat management relies on having some parts of a building extend high up in to the sky or down into the ground. That sort of construction is heavily regulated these days, by height zoning -- which tends to impose the same limit for a whole parcel, eradicating towers, chimneys and steeples -- and by the great deal of infrastructure underground (sewers, wires, etc). Incidentally, these regulations rule out the construction of the building we're looking at now -- you'd waste the entire "top floor" on a chimney! It would just not be cost-effective relative to a design that fills the zoning envelope with usable space.

The building you're in was probably much cheaper to build. The trade-off between efficient thermal regulation and margins was made quite consciously, I'd guess.

Energy prices are too low.

If electricity becomes more expensive, buildings with more mass and room for the air becomes cost effective again.

Many modern buildings are indeed wasteful, maybe they could use half the AC. But comparing to traditional buildings which were grand public spaces may be a bit misleading -- that mosque in Cairo may well occupy the space of 100 apartments, and provide cool shady space where the occupants of 10 of them can sit, and zero bedrooms.

I've experienced the same in all these old forts, palaces, mosques and temples in India. Somehow, they would remain cool even in India's brutal heat.

Even the old British era colonial buildings would remain cool in summers.

Would love to know what material and design choices cause this effect.

Perhaps not pertinent, but the evolution of the sash window to provide air circulation has always impressed me:


By opening at the top and bottom it lets hot air out, and in doing so lets cooler air in below setting up a circulation.

I just liked how an idea that must be a few hundred years old has evolved into a useful design.

Yes, for example the Lotus Temple in New Delhi was remarkably cool when I was there, even though it was 90+F outside.


Most advanced passive cooling in traditional buildings I see seem to be in the Middle East and I don't recall every seeing any passive cooling in traditional Western architecture. The loss of passive cooling is probably a consequence of the homogenization of architectural styles we've experiencing for the past several centuries.

The ancient romans had implivium, https://en.m.wikipedia.org/wiki/Impluvium, to do the same sort of job. The water in the pool would cool the surrounding air and air drawn in from the opening in the roof above would circulate it through the surrounding rooms.

If western architecture means northern europe, then I think they were rather more concerned with heating than cooling. Southern europe took a lot more care (fountains, shutters, huge thick walls...). But it's still a long way from the desert climates where they did really serious wind & water cooling.

You do see it in the US southwest to some degree (e.g. Santa Fe) although there is of course lots of architecture built around air conditioning as well.

Whatever happened to architecture that is actually good?

Boy, if any of the builders from ancient times were around to see some of the monstrosities we've created.

> Boy, if any of the builders from ancient times were around to see some of the monstrosities we've created.

They would probably be amazed at some of the structures we can create and others they would just shrug at... but the same can be said for structure of their time.

> Whatever happened to architecture that is actually good?

Customers and economics.

A king telling an architect to build the greatest church in the world and mass-produced materials being unavailable resulted in some of the great structures of antiquity.

Now, you have a corporation asking how a structure can look distinct while being cheap, and you get the stuff we build.

Thank god at least for LEED branding, even if it's a compromise.

True. I would guess that mechanization and cheap building materials displaced craftspeople in the marketplace.

I wonder if there's also a cultural explanation as to why movements like brutalism caught on. Even 50 years ago buildings in the US were a lot more elegant than they are today.

As an almost architecture major, most architectural styles can be better understood by thinking "What's being rejected?"

It's a pretty insular culture (less so farther back, moreso the more modern you get), so essentially everyone knows the recent and current style... and then wants their work to be different.

When someone hits something that resonates, that gets copied, becomes the new dominant style, and then the cycle repeats.

Modernism (and then brutalism) was a rejection of the florid, nature-themed, complex styles that came before. It was literally "less is more."

I'd personally say that the longer a style lasts, the more derivative hacks you get with less talent, claiming to be designing in its name.

Maybe the good stuff we see surviving is just survival bias? I know that in southern Portugal, today, they have marble floors and keep the shutters closed all day, maybe with Windows open for circulation. Houses are nice and cool

The HN policy of using the title name makes it difficult to appear interesting.

I posted this prompted by a comment discussing the cooling property of solar panels:


Actually I would say it's the opposite: if there are some upvotes on a post such as this, I'm very much inclined to find out why an obscure Wikipedia article has made it to the front page. Some weeks ago someone else actually described this concept as a form of clickbait.

Well, I was very curious to see what made a building in Zimbabwe remarkable. Usually you only hear of Zimbabwe because of inflation.

I wish the Wikipedia article had more information about the drawbacks of such a solution. The main ones I can think of are cost of design, limited sunlight, and that it's only a viable option in temperate climates, but I'm sure there's more.

This is an interview with the architect:


What comes across is that the client was very keen to do this, is there any reason why there aren’t many other buildings like this?

Mention is made of Portcullis House, office by the Houses of Parliament. Are they expensive to design? Just unusual for architects to design?

Shouldn’t this be standard where possible?

- Small windows with limited view. Less of a problem for a shopping mall since most stores I know don't seem to have windows at all, but I'd expect it to be perceived as unpleasant by western standards.

- If it's an unusual design, using it means you're taking a big risk. If it works you save money, if it doesn't you have an uninhabitable building that may be hard or impossible to retrofit to a "normal" system.

http://www.mickpearce.com/Eastgate.html has some data, which looks remarkably good.

There's quite a trend for new 'Corporate HQ' buildings to incorporate this kind of stuff to burnish their environmental credentials - e.g. Bloomberg's new London HQ [0].

If you're just a development company building offices to rent, you'll include anything your prospective tenants are willing to pay for! A lot of those will simply want climate control to be as cheap as possible, so it'd boil down to whether the aircon / energy savings outweighed the extra capital costs incorporated in the rent.

[0] https://www.bloomberg.com/company/announcements/bloomberg-mo...

There’s a website called Carbon Culture which shows the energy use of a building, and they have a page for Portcullis House which uses the same chimney method. Although I doubt cooling in London is as much of an issue as Harare.


Portcullis House Wikipedia entry, though doesn’t seem interested in its energy use:


> Although I doubt cooling in London is as much of an issue as Harare.

The climate is similar in both cities.

Harare's average January (summer) daily mean is 21°C, London's (July) is 19°C.

The average highs are 26°C and 24°C. The high-low range, which looks to be important so the building can cool at night, is 10°C in both.

Harare is 15 degrees south and London is 50 degrees north of the equator. The sun is much more intense in Harare and occupies less of the day, allowing more time for the vents to cool the building. That said, this principle can be applied in London as well.

Does London even need cooling on 99% of days? 25 degrees is the temperatures air-conditioners are often set to in the tropical country I live in.

If your AC is producing 25-degree air, it'll be quite dry, which London is not. (But Harare is, I believe.) That said 25 should still be fine, but there are days which are 30 & humid, which are pretty uncomfortable. Not so many, but more than 1% I think.

Most buildings there are also designed much more for winter. The windows seal well but often don't open that wide, and there will be a fire door making sure you can't get cross-ventilation, etc.

In america the standard airco setting is 18c to accommodate people in business suits. Given that London has a pretty big financial sector (with a lot of suits) they might have something similar. The same could hold for parliament.

Also London’s day lengths vary far more between summer and winter.

Glass towers are, if not beautiful, a status symbol. Especially because brick looks stuffy and traditional whilst concrete invokes 80s brutalism. If you want a modern looking facade, glass is an easy choice.

Moreover, if temperature is properly controlled, a working or living environment with a lot of sunlight is actually very pleasant. Most people prefer sunlight over artificial light.

I guess this combines to suppress demand for the style shown here. I recall seeing similar attempts to make skyscrapers more passively cooled. They seem popular, but are quite expensive.

Glass is to me very 80s...

What does a modern building look like for you?

Modern large office buildings these days are mostly glass exterior, but with other prominently visible materials (metal, concrete, maybe wood) as accents. Usually some big diagnol lines or at least visible sections.

Older all glass offices present as a single plane of glass, sometimes with light/dark striping.

Modern shopping centers, or residential have different looks, of course; although high density high rise residential gets fairly close to high density high rise office.

>Pearce's practice is in Harare, and he specialises in buildings which are low cost, low maintenance, and have low environmental impact. His projects try to make best use of locally available resources, and include Harare International School Arts Centre, Harare Hindoo Temple and Chinhoyi Provincial Hospital, Zimbabwe.

This sounds more like the architect's resume than a Wikipedia article.


Hawa Mahal in India uses venturi effect for cooling.

I've been to the Eastgate Centre a couple of times and think it's an excellent building -- aside from its passive cooling, its retail space is quite people-friendly and attractive. That said, it's probably worth noting that Harare is not a particularly hot city, courtesy of its altitude (1500m/5000ft.) I wonder if this would be as effective in a truly oppressively hot place like the Horn of Africa.

Reminds me of Yakhchāl, the 2500 year old Persian "refrigerator." https://en.wikipedia.org/wiki/Yakhch%C4%81l

On a smaller scale, the concept has been used in the Middle East: https://en.wikipedia.org/wiki/Windcatcher

If there is wind, you don't even need the fans that are used in the basement of the Eastgate Centre.

A high efficiency high rise for a much less temperate climate that incorporates some of the same ideas:

* https://en.wikipedia.org/wiki/Manitoba_Hydro_Place

This building is a masterpiece and a towering (no pun intended) achievement. If I were 18 I would make this my career, and today would be the day I would talk about with journalists 20 years later when they asked where my ideas came from!

The tower at PNC in Pittsburgh is a new skyscraper that has a similar solar chimney model and relies on passive aircon for 42% of the year. https://www.architectmagazine.com/awards/r-d-awards/award-th...

They said that no direct sunlight must fall on the external walls at all and the north façade [direction of summer sun] window-to-wall area must not exceed 25%.

Pass. Natural light (and tons of it!) are a hard requirement for anywhere I actually want to work. (Besides light and airy spaces being generally pleasant, I have mild SAD.)

In any case, I'd rather use modern air conditioning, which is stunningly efficient. It also actually produces temperatures I can live in. They don't quote actual interior temperatures (or humidities!) but I'll bet their "acceptable" is 78F+. Anything north of 70 and I am a sweaty mess. (If you're cold, put on a sweater; I can't exactly strip in the office and you wouldn't want to sit next to me anyway!)

Complaints about air conditioning are mostly a form of modern self-flagellation. If you're not suffering, you're not doing enough for Gaia. Cost/benefit calculations simply don't enter into it (if they did, someone might point out that eliminating all cooling whatsoever would not even move the needle on US energy. Consider https://www.vox.com/energy-and-environment/2017/4/13/1526860... and https://www.eia.gov/tools/faqs/faq.php?id=1174&t=1, from which you can see that cooling is 9% of electricity, which is perhaps 38% of total energy usage.)

> Complaints about air conditioning are mostly a form of modern self-flagellation.

For your, and HN's consideration, we are losing regional vernacular architecture because of air conditioning. One of my fav episode of 99% Invisible makes this case, that once architects outsourced the solving of thermal problem to air conditioning, they could build boxes of steel and glass anywhere. It's contrarian to Wright-ish principle of building with the land ("buildings should not be on a hill but of it"). I recall there's a part about how people would rather open a window for cooling and get moving air, instead of being inside a confined air conditioned space. The episode also visits a "baoli" of India and the modern building designed with its features.


Honestly? Good.

Architects and architectural styles are much more concerned with their particular artistic vision, and status signaling within their tribe, than with whether their buildings are pleasant to live within. (See: brutalism, for the worst case, but this applies widely.)

The more practical realities force architects to abandon their pet styles and build efficient places, the better. I have to live there; they don’t.

Direct sunlight near equator would be a hard no for anywhere you want to work. Much rather have large/deep overhangs as this building has and most house designs integrate so you have indirect sunlight for most of the day. It will still be very very bright inside with ambient light refracted inward

Sunlight still gets inside, it's just not built like a greenhouse. Search for photos of the interior of the building... it looks lovely.

One big benefit that the article mentions is that you get a constant supply of fresh air, vs the recycled air that is typical in air conditioned buildings.

So any office you work in must be kept at 70F or below for your comfort, and your colleagues must wear sweaters?

Could there be a heath and fitness change you could make so the rest of the world wouldn’t have to suffer in cold offices? Working perpetually cold is miserable, and extra layers is only a partial solution.

Also, no matter how efficient modern air conditioning is relative to older systems, it’s still a financial expense that should be measured and minimized where possible.

I'm in the same boat as the person you're replying to. I have a really hard time in temperatures above 23-25C (sometimes slightly higher if it's really dry) and I really wouldn't want to work in such an environment. I sweat extremely easily in the heat, even idle, which is deeply uncomfortable.

I'm noting how incredibly rude your reply is; implying that there's a fitness issue causing the condition (at least in my case, there is not), and implying that GP wants to impose "their rule" on people who won't like it.

I work at home, FWIW, and my girlfriend doesn't like heat either. It's a good arrangement. You didn't get the chance to make assumptions about me, but please don't make assumptions about GP either.

If it's 70F indoors and you need to wear sweaters to keep from shivering, you might have a health & fitness problem just as much as the opposite case.

If anything north of 70F is too hot for you, you have a medical condition which should not be solved at the building scale.

There's a lot of ways to get natural light into a building without having direct exposure to sunlight.

An example would be Masdar City:


Eastgate centre is one of the most popular houses in the area. I would like to live in the house similar to Eastgate centre. I know that find a house like that is practically impossible, however, you can find the house great to live in online. I just visited <a href="https://pin.tt/realestate/residential-sale/">Pin</a> and found myself a cool house to rent.

Eastgate centre is one of the most popular houses in the area. I would like to live in the house similar to Eastgate centre. I know that find a house like that is practically impossible, however, you can find the house great to live in online. I just visited https://pin.tt/realestate/residential-sale/ and found myself a cool house to rent.

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