Things look up when you enter; there is an interior revolving door and a sign that notes that it is there to keep the polluted exterior air outside.

It has a generous and welcoming lobby with a bar at one end and a display of organic wines. The hotel currently serves mostly Broad's visitors; changes are being made to provide easier access to others, with a new lobby and wine bar at the lower level.

The plan of the building is a conventional centre hall design that is pretty universal; a nice touch is the natural light in the elevator lobby, giving up a possible unit to create a more generous space.

I am staying in a suite; it is all bamboo floors and walls, simple and comfortable furnishings, a generous bathroom and an odd extra toilet that take up space that could have been better utilized. There is what once was an opening hopper window, now sealed with a sticker saying that the air inside is 100X cleaner than the outside air.

Outside the triple-glazed window is an electrically operated exterior venetian blind; inside is a blackout blind. I tend to keep them closed so that I don't have to see what is probably the worst window cleaning job I have ever seen, a point that I note because it is relevant- in this 2010 building the windows are punched in and broken up by mullions which makes them harder to clean; the newer buildings have a flush skin. You need to clean the windows a lot here due to the air pollution and the smooth, flat facade is a lot easer to deal with.

INTO T30 HOTEL

The T30 is a different kind of hotel and a very different building; Broad has learned a lot in the two years separating the two. The cladding now is a slick glass, two separate double-glazed panes with the venetian blinds between.

The lobby is a site-built pyramid that bangs clumsily into the exterior of the building, but provides a generous space inside.

This is a much larger, busier hotel that is a bit down-market from the New Ark. All of the interior finishes and furnishings were prefabricated as well and the entire finished product was built in 15 days. (The New Ark interior finishes were done more conventionally.) The video of its assembly is spectacular.

In the cafeteria, most of the food comes from the company's organic farm.

Signs exhort you to eat every grain of rice, every drop of wine(if only you could find a drop of wine).

Here is something I do not understand, being used to North American building codes. There are two fire exit stairs with fire-rated doors at each floor, but they both open up at the lobby level in the same place, with no doors. The whole point of having two sets of stairs is that if one gets blocked or full of smoke, then the other is accessible. They are not very inviting stairs either.

The elevator has gauges that tell you how much electricity it is using on the way up and how much it is generating on the way down. There is a display in the room that tells you how clean the air is inside and how dirty outside, and lets you mix fresh and cooled air to adjust the temperature (although the english button didn't work). The LED lighting goes on and off as you move through the corridors, following you like a puppy.

The walls are insulated with eight inches of rock wool; this place is quiet and comfortable.

In the basement, a big Broad absorption chiller runs on the waste heat from a generator; waste heat also powers the laundry. Compared to normally built hotel, the T30 is using a fifth of the energy, a quarter of the water, with air that is 20 times as clean as outdoor air. You can feel it; I have been in so-called green hotels in New York with noisy through-wall heat pumps