The invention deals with buildings walls capable of varying their thermal insulation properties as a function of the external and internal temperatures. This characteristic is obtained through the drowning of pipes made of any material used for the transport of liquids; a heat-carrying fluid flows inside the pipes, pushed by a pump, at the aim of transporting heat in the direction of the thickness of the wall, from the indoor to the outdoor environment and vice versa.
Patent Status
PENDING
Priority Number
102021000005219
Priority Date
05/03/2021
License
ITALY
Market
The potential market for this technology overlaps with the entire built heritage of moderate climate countries, with particular effectiveness in buildings with a low envelope efficiency. The most immediate application would be connected with energy refurbishment interventions, facilitated also by the incentives that will probably be put in place at European level to comply with the requirements of the recent revision of the EPBD Directive on the energy performance of buildings.
Problem
The problem that the invention aims to solve is that of creating adaptive walls that change their thermophysical properties as a function of the required internal comfort conditions and external environmental conditions. If in winter season walls are generally more performing the greater their thermal insulation capacity, in the intermediate and summer seasons, the building physics is more complex. In late autumn and early spring, solar radiation can heat the external surfaces of walls and this energy can be transported immediately inside buildings providing space heating. In summer, for a non-negligible part of the day (especially at night), the outside temperature is lower than the inside set point for thermal comfort. During these periods, the transmission of heat (from the inside to the outside) should be facilitated, i.e. the transmittance should be enhanced to the maximum, in a controllable manner. The first results of the walls analysed through numerical analyses (finite volumes simulations) show a possible variation of the thermal transmittance of the proposed walls from 0.23 to 2.50 W/m2K.
Current Technology Limits
As far as the inventors’ knowledge, there is no similar proposal in the construction sector, as no variable thermal transmittance system is yet available, with the exception of devices which include walls with modifiable air gaps, but the effect on the variation of the global thermal insulation properties is limited and with poor control capacity.
Killer Application
Experimental measurements of a real wall on a “Hot box” system are being carried out for the validation of the numerical simulations. An installation on a typical building was also hypothesized and a comparative analysis was carried out with the same building, without the installation of the invention, equipped with the Best Available Technologies in terms of thermal insulation. The results showed that savings on heating and cooling needs of up to 40% can be achieved.
Our Technology and Solution
The technology is extremely simple, as it consists of a pipe crossed by a fluid (even water, but a water + glycol mixture is more suitable to avoid freezing) and a small pump connected to a control system which drives it to operate when necessary. In winter, as long as the temperature of the external wall remains lower than that of the internal, the pump is inactive, and the wall behaves in terms of thermal insulation like a classic insulating wall. When the two temperatures are inverted, i.e. when the temperature of the external wall becomes higher than the internal one for any reason (solar radiation arrival, increase in air temperature in warm climates and far from winter lows), the pump is activated to transfer heat from the outside to the inside. When the pump is running, the fluid flows in the pipe and becomes the heat carrier from the outside to the inside. In summer mode, the operating principle is exactly the same, except for the pump start mode, which is activated only when the outside wall temperature is lower than the inside one. The installation consists of laying a series of pipes at different heights in the walls and it can be performed by a plumber; the electronics are just as simple, since it is sufficient to connect the temperature probes with the pump.
Advantages
Roadmap
In the next six months experimental measurements of a real wall will be carried out on a “Hot box” system for the validation of the numerical calculations and to bring the invention to TRL 3 and 4.
With the involvement of external partners, such as companies operating in the building sector, a test can be carried out on a real building to arrive at TRL 5; this activity will last approximately one year. The goal is to confirm the efficiency data obtained so far and then start production.
TRL
Team
