No, please no concrete for the walls. I have lived in an an apartment that had concrete walls in Bangalore and it's just terrible. Concrete amplifies both hot and cold weathers. So you are spending a ton of money on air-conditioning and heating as well. Admitted, in Bangalore you don't need heating but I can't imagine a concrete house in the northern hemisphere.
Like others have stated, solid bricks, stones or even clay bricks are a better alternative. You still need to use cement but that's alright.
The thermal mass in construction is like adding inductors and capacitors to a circuit. It has to be tuned to the local climate. The best you can do with thermal mass alone is an interior that is always the local mean temperature (like in a cave).
So in a thermal wall, you should match the rate at which heat conducts through the wall to the thickness of the wall, such that it takes about (12 + 24n) hours for heat applied to the exterior of the wall to radiate from the interior of the wall, and vice versa. You're trying to eliminate the daily temperature variation, so that the heating or cooling load will be more stable.
Adding phase-change materials to the concrete mix would help, but for the most part, the traditional building method in the region has been tuned by trial and error. If you build an adobe house in New Mexico, you make the walls from local materials, with the same thickness as the traditional homes. Or you get an engineer to do the thermal calculations.
Most houses built in the US just stick to the building code, which is generally good enough to accommodate local weather conditions without breaking out the calculators.
Right. Writing code to estimate the optimum thickness was one of our homework problems in modeling and simulation class, back in the day. I expect running that sim on a PC would be trivial today, but back then it took a significant amount of time on a fast SPARCstation.
(the basic idea was to model the wall as extremely thin slices so the heat transfer between slices can be approximated easily. How thin? You kept making them thinner until the model stabilized).
The wall thickness we derived was very close to the wall thickness traditionally used by the indigenous people of the area. What are the odds? :-)
