Keeping Cool When Inside is Still Outside

cafeteirs

by Dan Schafer

We talked about building a new cafeteria for our factory workers for several years. It wasn’t that we didn’t know we needed one.

Our Make-do Cafeteria
When we bought our property nineteen years ago it was an orchard with a kind of quaint little house.  For the first year that house, along with a few makeshift out buildings, served as our factory while we built our main (500 square metre) building. After we moved into our new building that little house seemed the most convenient place for our workers to have their noon meal out of the sun and out of the rain. We upgraded the little kitchen. We repainted the house inside and out and put some linoleum on the floor. We made some nice long wooden tables and added enough wooden stools for everyone. Considering the level at which we were as a business and the level at which our workers were in their expectations, we had something quite nice.

But “time hurries on, and the leaves that are green turn to brown;” and the thin cement floor poured on the ground for a single family dwelling, developed a decided dish shape under the weight of fifty plus workers every day. And after fifteen years the wooden tables and stools were not as solid and glossy as when they were built either. Nor were the walls and ceiling as beautiful as they once were. Paint helps, but that little house was getting five years of wear for every year we were in it compared to a single family dwelling.

Talking About a New Building
No, we knew we needed something new. But something new requires a plan: how big to make it, how much money to commit to it. It requires a commitment of land in a place that will not complicate future needs. Thought and agreement were needed on all those factors, all for the sake of a building that our workers use about half an hour each day. We enthused at first about the idea of a multipurpose building on two floors that could house an air conditioned library and computer room above, but though an attractive idea in itself, it began to seem a too permanent and too imposing kind of structure that would distract resources away from our main concentration—making beautiful jewellery in our factory and developing skilled and professional young men and women. Consequently, our indecision about a plan and the continual need to develop our business all conspired to keep the cafeteria on the sidelines. Thus the several talking years.

Getting some Actioncafe
The turning point came when we found a local architect. Then the project began to be a lot more manageable. That was the case, first, because, as always, until one actually starts to move on a project, the multitude of unknowns makes the problem seem bigger than it is. Secondly, this architect knew what sort of plan should pass in the local planning office and what sort might have difficulties there. That meant we could both have a plan and be pretty much assured the plan would be one on which we could proceed, both in the one contact.

How to Make it Cool in Thailand
In Thailand the most important thing about keeping cool is getting out of the sun. Any shade is better than no shade, but the shade of a nice tree always seems better than just the shadow of a building or the shade of a roof overhang. In fact it not only seems better -- it is better -- because trees are actively cooling by transpiring water vapour through their leaves. Since our plan now made no provision for an expensive, energy-hungry, air-conditioned monstrosity, trying as much as possible to emulate the shade of a tree seemed the best objective in designing our new cafeteria.

roof

Part of what makes the shade of a tree cool is a nice breeze blowing through, so we decided that there would be no walls, apart from the kitchen and rest room area. But the remaining important thing was how we would make that tree-like roof. First we decided to support it by steel trusses rather than pillars in the middle so that we could create a nice airy open space. Second, we designed it as a hip roof, that is, all four sides sloped instead of just two, so it could have a long overhang all around. That way every side of the building was protected both from the heat of the sun and from blowing rain. Third we needed a way to make the roof as reflective of the Thai sun’s heat as possible.

How Not to Make it Cool
But this last element was essential. When we had built our main factory in 1990-91, the contractor put similar roof tiles on similar steel rafters. But that was all. Since then we have learned very well what it is like under that roof when the Thai sun is shining. On a typically sunny day of say 35 degrees C (95 F), that attic temperature will be 45 to 50 degrees C (113 to 122 F). And the steel rafters inside become  too hot to touch. Yes, it is a sort of shade, but a cooking shade. The radiant heat from those sun-baked tiles acts like the heat from the elements of an oven.

Stop That Heat
So what was lacking? An innovative heat barrier. What we looked at was a thin section of foam insulation sandwiched between two sheets of aluminium foil. The key is the reflectivity of the aluminium foil to beat the radiant heat. Technically the combination can achieve an R factor of 10-19—think the time it takes the heat of the coffee inside the cup to get to your fingers holding it, the longer the better—depending on the installation situation and the foam thickness. Those erstwhile oven-element roof tiles above have nothing to do this way but to send that radiant heat right back the way it came because of the reflectivity. Then the foam acts to resist any conductive heat warming the foil. The cost is not a nothing—about three dollars per square metre of roof area for our application. But for the benefit gained it was a real bargain. So, although using different technology than the tree, we achieved something of the coolness of a tree’s shade.

Make it Beautiful, Toocafe
Since for us, that foil insulation would serve as the “ceiling” of the dining area of our cafeteria, we needed to work out how to get it to stay neatly in position rather than sagging between the rafters. We ended up stretching some wires vertically up across the rafters and then stretching the insulation over those. That solution high above the seating area actually added a nice looking finish above the exposed trusses. Then in order to secure the roof tiles and not damage that nice layer of insulation, all our tile attaching was done from the top.

Making it Cool The Right Way
Of course, air conditioning instead could have achieved a cooler result, but at what cost? Energy-wise infinitely more, because our tree-shade roof is using none. Ambience? No comparison! The nice high-ceilinged space such as we now have would be unthinkable with air-conditioning, especially considering the running time to get it down to temperature for only half an hour to an hour per day. Air-conditioning certainly has its place, but how much more enjoyable to have your lunch in nice open-walled seating with a view of the trees and grass and the sound of the birds!

Now that the cafeteria is finished, we as management find it so nice that we sometimes use it for whole-factory meetings and invite visiting business contacts to eat lunch with us there. Sitting inside it is like being outdoors and yet pleasantly cool.

So just as in business, where one needs to learn to use “appropriate” technology to achieve maximum productivity at a practical cost, so in this building project we had to find the right level to shoot for that could get an “appropriate” result. Many of our failures in problem solving come from a lack of flexibility about the goals and solutions. We get locked into our little mind-set, whether it is a Western one, an idealistic one, a lazy one, or whatever our particular weakness may be. And now, in fact, in our cafeteria case, what may have seemed to be an adjusting down of our goals, essentially was more ideal than our imagined “ideal”. We have a better result in every way that matters.

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