You know the higher the thermal coefficient (thermal capacity), the higher the capability to absorb energy. The same thing is true about phase change materials.

I assume the inertia you are talking about is the same thing. It means a lot of energy is required to increase the temperature(another definition for high thermal coefficient)

what I can tell about such materials is that, these materials make a good match with a stream that doesn't vary in temperature. like a condensing steam. 

other point may be that these materials are interesting where the objective is to minimize the the volume of the system.

I would appreciate it if you give more information about the application and other specifications in order to continue our discussion on the issue. 

You know the higher the thermal coefficient (thermal capacity), the higher the capability to absorb energy. The same thing is true about phase change materials.

I assume the inertia you are talking about is the same thing. It means a lot of energy is required to increase the temperature(another definition for high thermal coefficient)

what I can tell about such materials is that, these materials make a good match with a stream that doesn't vary in temperature. like a condensing steam. 

other point may be that these materials are interesting where the objective is to minimize the the volume of the system.

I would appreciate it if you give more information about the application and other specifications in order to continue our discussion on the issue. 

It really depends on the climate. It's a great material for the cold climate which receives good sun radiation in winter. I dough about it's efficiency in the hot climate since the impact of the energy that it can absorb from the environment, is not as much as it can give it back when the mechanical cooling system starts working.  

If the purpose is to store and release heat, the best substance is water.

A law states that the product of density and heat capacity is almost constant for all substances, with the exception of associating substances, like just water

High density, high heat capacity, high chemical inertia, high heat transfer coefficients, low cost. Difficult to match.

@Farzad is right that climate is important but winter or summer won't matter.

in fact the temperature difference between day and night is critical. If the day is hot and the night is cold, heat can be absorbed in the material and at night it releases the energy.  This way the system decreases both heat and cooling required.

Could you give us the thermal properties (thermal conductivity, density, thermal capacity)  of this material?

There are several thermal properties related to energy efficiecy:

Thermal conductivity, that is the capacity of a material to thramiit heat by conduction. Low thermal conductivity materials are used to reduce het losses or gains

Thermal capacity, that is the property to store heat at steady state

Thermal diffusivity, which is the property of a material to quickly thransmit heat. It is the square root of the thermla conductivity divided by density an thermal capacity.

Thermal effusivity, which is the capacity of a material to store heat and give it back later. It is the square root of the product of thermal conductivity, density an thermal capacity.

In my opinion, the energy efficiency of an object (e.g. a house) depends more on the use of the materials than on the materials themselves. For example, the thermal inertia of a house, i.e. the natural stability of its internal temperature, depends not only on the materials (natural tempearature stability needs a high thermal effusivity) but also on the location of possible insulating materials: if outside the building fabric, its natural stabililty will increase a lot, while it will be strongly reduced if an insulating layer is placed inside. 

Anyway, as it was already said, it depends also onthe climate. The architecture should not be the same in Iceland and Singapore!

Monia, if by Thermo-stone you mean this (http://www.thermostone.com/index.cfm/products.htm) then it is a thin film heater. It means that it is not a passive element. Being a heating element, its efficiency is nearly 100%.

Indeed, when searching for Thermo-stone on the web, one get a large amount of various products. Therefore, more information is needed to give a proper answer. 

By the way, the thin film heater (as any electric heater using resistances) is not very efficient: Indeed, it degrades electricity into heat with 100% efficiency, but with the same amount of electricity, one can get much more heat with a heat pump! In addition, several kWh of primary eneergy  (about 4 in Europe) are needed to produce 1 kWh of electricity.