The physics are straightforward: when a material changes phase, like ice changing to water, a great deal of heat is absorbed. When it goes from water to ice, heat is released. That's why ice doesn't instantly melt in your drink and why it does such a good job of keeping it cool; it takes time.
Phase Change Materials like paraffin are being used more often in buildings to act as thermal flywheels, storing heat in the day and releasing it at night, or vice versa. You can buy drywall impregnated with it. Architect and engineer Raphaël Ménard and designer Jean-Sébastien Lagrange are making it beautiful with their Zero Energy Furniture, of which the Climactic Table is the first project, now being shown in Milan. "The project represents a result from a dialogue between design and engineering, structural design and energy savings, thermal well-being and rational aesthetic."
The designers are trying to solve "energy efficiency and climate control issues at the furniture scale rather than at the building scale," by absorbing and releasing heat to regulate temperature.
This table has a very high thermal inertia, despite its sharpness. The secret lies into innovative use of phase-change materials (PCM), integrated between the surface of plain wood and the folded sheet of anodized aluminum. The waved geometry of the conductive aluminum fosters thermal exchanges between the room and the PCMs located inside the Climatic Table. The folds of the light-weight sheet of aluminum give also an excellent structural rigidity and carrying strength. Thus, the plateau might have a very large span.
The designers make some remarkable claims for the furniture, energy savings of up to 60 percent of heating and 30 percent of cooling demand. "For housing, this furniture reveals its regulator property and allows an higher comfort during hot season. The overheating is absorbed by the Climatic Table and re-emitted when room temperature is tempered."
UPDATE: To clarify, phase change material only works (and saves energy) if there is a significant temperature difference between day and night spanning the temperature where the phase changes. So it is great in places like Arizona or Spain, where there are big swings. And as Mr. Steve notes correctly, in a well insulated room this would do nothing.
In praise of dumb technology
It truly is an example of engineering made beautiful, a lovely thing to look at. But one has to understand under what circumstances it would actually work, and how well. It will work in France; many people there believe that air conditioning is unhealthy and causes colds. There, a table like this would make a difference; it is concentrated thermal mass that would release its heat at night and absorb it from the room by day. It is what I have called dumb technology, because it just does it all without thinking, without controls and electronics.
However in North America or in any air conditioned space, this would just be a big thermal drag. Imagine having a Nest thermostat which cranks up the AC when it smells your sweaty presence. This table would fight it all the way, releasing heat and slowing the change of temperature. The smart thermostat would have to run the AC longer and would use more energy because the dumb table keeps resisting change.
I have previously sung praises of the dumb home; I will now praise the dumb table. They were made for each other.
The designers note that the Zero Energy Furniture line is growing; I love some of the ideas shown here, particularly the semi-enclosed chairs and sofas that would be cool places to sit on a hot day. They are seriously on to something here.