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Wind Tower

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In Hong Kong, the Hong Kong Housing Development Authority continued to develop and deliver new housing for the population. Most recognizable of the various types is the tower block with a cruciform typical floor. I’ve been mentioning this since at least 2017 as an example of a stable typology that is difficult to improve on. All rooms including bathrooms but especially kitchens can be naturally lit and ventilated even if they probably don’t have what we call a view. Even the elevator lobby has natural light and ventilation. The cruciform plan allows eight dwellings per floor and also allows the towers to be built close together or even attached yet still maintain maximum distance between habitable room windows.

The Chinese Apartment

Things are done a little differently on the mainland. The pressure to develop land at high densities is still there but not as great. This means that more attention can be paid to orientation and achieving a more equal distribution of daylighting and ventilation. Tower blocks are general slabs and not points blocks and they are oriented east-west with all apartments generally having a southerly aspect. This next image is an overview of a typical development under construction not far from me. It’s from marketing materials I picked up at my local supermarket. The site narrows towards the bottom right which is south. Taller buildings increase in height towards the north and to a lesser extent to the east, making sure those spaces between the buildings receive maximum daylighting. All apartments will be dual aspect with south being one of those aspects. There will be a balcony on the south side but for the drying of laundry. The city of Wenzhou where these apartments are, is said to be blessed with an ideal location between mountains to the north and water to the south. Whether you believe in fengshui or not, it’s currently 35°C here with 62% humidity and a slight 3m/s breeze that makes all the difference.

Buildings 4, 6, 9 and 10 are modern versions of the layout of the apartment in which I currently live. I’ve redrawn the fire-escape plan so you get the idea. South is down, dimensions approximate.

  • Care has been taken to give windows to the bathrooms and kitchens of the inner apartments. This has advantages for illumination, ventilation and energy saving and also makes them easier to use.
  • Apartments have south-facing balconies but they open off of bedrooms, not the living room.
  • The washing machine will be on one of the balconies, the laundry drying rails most likely on a south-facing one.
  • The window of the living room opens onto the deck access for the apartments that side.
  • There is no guest bathroom, as is common in many countries.
  • The kitchen is adjacent to the living/dining area but can be isolated by sliding glass doors. In the L-shape of the kitchen counters is a shaft into which the cooker exhaust fan exhausts. Exhausted air is not recirculated but is filtered to remove oil. This little detail says a lot about the culture and what becomes important when people live in close proximity.
  • The corridor is open but used for ventilation only and not for kitchen exhaust.
  • There’s no garbage chute. Everybody takes their own trash downstairs to the recycle bins.

Apart from the living room window /access conflict, all these characteristics are present in the newer and more expensive apartments of the development shown earlier. Key plans show the inner apartments (left, below) still have to be passed by to access the outer apartments (right, below) and problems of privacy are usually usually ameliorated by having a detached access corridor create a void between it and habitable room and kitchen or bathroom windows. These marketing layouts don’t show this.

This next development solves that problem by having only two apartments per core, and mirroring that unit to produce give four apartments per level. Even when two apartments aren’t going to happen for reasons of adding market value, they might still be used to build into the corners of narrow or oddly-shaped sites.

There’s much that’s good about the internal organization of these residential towers. In the UAE I’d taught students how to design Western-style apartments with internal bathrooms and internal yet exposed kitchens, with an entrance hallway, guest bathroom, and separation of areas for living and sleeping, and/or for family and guests.

We’d do the same for one-, two- and three-bedroom apartments as well as for a studio although many students, especially those who’d never been inside an apartment, found it difficult to understand what one was or why anyone would want to live in one, let alone a studio apartment. As a next exercise we’d combine various apartments into a typical floor for a given site. The apartments would invariably be single-sided and as many as possible accessed by a corridor that would always be internal, and artificially lit and ventilated. This next is one from a former presentation. It’s of a generic apartment building, designed probably in the sixties by SOM I seem to remember.

It’s a product of the standard template for apartment buildings because it has a low build cost. Three elevators and two stairs for fifteen apartments and no-one’s walking past anyone’s window because there aren’t any opening onto the corridor. There are no balconies because everyone has a dryer. Apartments are on both sides of the corridor for higher sellable area to non-sellable area ratio. In general and from my short experience, I’d say Chinese builders and developers aren’t ones to waste resources either, but the generic product is something very different. Developers never want to build at a loss so my feeling is that if they built anything else it simply wouldn’t sell. The Chinese Apartment is how it is because it has evolved that way. This was my new teaching model for a while.

It follows the Chinese template apart from the detached core. To not detach it would mean redesigning the inner apartments so the kitchens and bathrooms have windows opening onto an indent on the south side. Detached cores probably don’t stack up financially or else we’d see more of them. None of my examples have them. If the windows and entrance to the blue apartments aren’t to be compromised, the only thing that can be done is to make it less detached. (Something will have to be done about those bathroom windows and recessing the entrance door will at least make them open towards a space travelled by fewer persons.) Here’s my first revision.

This is a better way of designing apartments. The International Style may have been international for commercial buildings but, for residential, people developed their own configurations more suited to how they wanted to live. They weren’t being critical. Just for fun, here’s Lake Shore Drive redesigned as Chinese apartments. I’ve added Western-style kitchens just to show it makes no difference.

Here’s what seems to be an early LMvdR sketch that correlates very well with the apartments as marketed.

People in Chicago aren’t going to want open corridors and cross ventilation in winter. Even though giving apartments an attribute of a detached house is generally a desirable thing, apartments where you stay cold until you’re inside your front door have never really been promoted as aspirational. On the other hand, people in China won’t be inclined to choose an apartment with the wrong orientation, an open kitchen, or no balcony. My Rev. 2.0 building is 5 x 2.5 bays as opposed to Mies’ 5×3 and my 4 x 3-bed apartments aren’t as spacious, but all rooms have natural light and ventilation, and all apartments have some portion facing south. Different strokes.

These towers adjacent to where I work have deep floor plates so I first thought they must have huge, long and narrow double-sided apartments two per core but no. Apartments are double sided but colleagues tell me living room windows overlook internal deck access. In other words, there’s corridor access around an airshaft/lightwell. It’s a known typology with known privacy issues.

But it was a surprise to learn that some Chinese apartments compromise on cross ventilation if not orientation. It also suggests developer-led pressure to shift the market and make the Chinese apartment as profitable to build as Western ones. Rev. 3 below is my first response. Southwards orientation is now no longer a driver and there’s no cross ventilation, although some form of through ventilation will result if the core is open at the top and bottom so prevailing winds generate a negative pressure and a resultant upwards airflow [due to either the Venturi Effect or the Coriolis Effect – I never was sure which it was]. This building has three types of shaft: 1) the functional ones such as stairwells and elevators, 2) those that separate the access corridor from windows, and 3) those that provide additional airflow and “internal” window opportunities so people indoors can see people moving around outside, and people outside can see who’s home and feel part of something larger. This has been a concern common to many of my proposals this past year.

But can it be improved? There’s always something that can be changed regarding the division of internal space. It’s fairly flexible but it’s just as wrong to assume one layout will fit all households as it is to assume households are incapable of adapting to where they find themselves. If it’s not going to be imperative that all balconies face south, then my only suggestion at this stage is to use them to bring added light and ventilation to those internal shafts as in Rev. 4.0 below.

  • These non-balconies are 2 metres wide and wide enough to dry laundry or for two sofas to oppose each other with perhaps a narrow table between. They are spaces to encourage a cooling or a drying airflow. They can be secured with grilles or screened with open brickwork, decorative CMU or similar. What they cannot be is fully enclosed.
  • There might be some structural efficiencies to be gained by making the inner apartment wall more of a tube structure reducing the size of the conventional core I’ve drawn here. Other people will know better.
  • I’m liking the layout of the end apartments. It’s about as basic as it gets, but it’s good value and works a charm. Surely I can’t be the first person to have arrived at this?

The Indian Apartment

This quadruple pairing of apartments with bridge – i.e. detached corridor – access to core reminded me of one of the standard Indian apartment types. The apartments in the example below each have two or three balconies and, although each of the apartments is dual or triple aspect, a desirable airflow is assumed to exist because of the spaces between the pairs but probably more for some than for others for any given time because the building is omnidirectional and prevailing winds are not.

Whether or not my proposal will improve upon airflow depends upon the frequency, strength and direction of the breeze. Unlike the previous tower layout dependent upon an updraft being generated, Rev. 4.0 has lateral airflow across gaps. This is what is possible if we don’t treat orientation as synonymous with airflow (as is the Chinese way) and are willing to compromise on orientation but not airflow.

  • Rev. 4.0 will be a very breezy building suited to hot humid climates where airflow is to be encouraged wherever possible, along with the obvious benefits of needing less energy for illumination and A/C.
  • Depending on height of the building, my Rev. 4.0 is going to cost less to build. It’s an integrated single structure and not five independent ones.
  • Because of the two fire stairs, the Rev. 4 blue apartments can be easily lengthened to have two or three bedrooms. The only addition is some extra void and some extra external, unfinished, un-climate controlled corridor to access the end apartments.

Airflow in Rev. 4.0 will be more or less equal for all apartments for north/south breezes, and still equal but to a lesser extent for the east/west ones. Taking that into account, here’s another way of doing it. Like a Yazd wind tower, Rev. 5.0 puts wind from any direction to use for maximum benefit.