Jaroslav Jerz; Arun Gopinathan; Jaroslav Kováčik
Abstract
The structure of aluminium foam is highly porous consisting of aluminium (or its alloy) filling up the space among gas pores. Although pores formed during foaming of aluminium melt are closed, there are always microscopic cracks in the walls of solid foam, so that the porosity is predominantly ...
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The structure of aluminium foam is highly porous consisting of aluminium (or its alloy) filling up the space among gas pores. Although pores formed during foaming of aluminium melt are closed, there are always microscopic cracks in the walls of solid foam, so that the porosity is predominantly open. This preference of aluminium foam allows to fill pores with a Phase Change Materials (PCMs) capable repeatedly to store and release a huge amount of latent heat of phase transition from solid to liquid state and vice versa. The excellent thermal conductivity of the aluminium, forming the pore walls, predetermines aluminium foam castings for the production of highly efficient heat exchangers in various industrial sectors, especially in the building industry. The most promising technique for the production of near-net-shaped structural components containing a dense aluminium surface skin and porous inner foamed aluminium structure is powder metallurgical route. Lightweight self-supporting interior ceiling panels impregnated by PCM presented in this contribution, utilize their high mechanical stiffness and their ability to store large amounts of latent heat at a constant temperature. The application of foamed aluminium appears to be very promising also for heat exchangers covering the entire pitched roof of the building which provides not only the better recovery of the heat from the building surroundings but also the dissipation of unwanted excess heat from the interior when needed.
Jaroslav Jerz; František Simančík; Peter Tobolka
Abstract
The energy efficiency of buildings is today mostly improved by upgrading the energy performance of the building envelope and facilities. However, huge energy reductions can also be achieved by a focus on the novel systems enabling to cover natural energy fall-outs resulting from generation much excess ...
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The energy efficiency of buildings is today mostly improved by upgrading the energy performance of the building envelope and facilities. However, huge energy reductions can also be achieved by a focus on the novel systems enabling to cover natural energy fall-outs resulting from generation much excess heat during the peak time (summer, day) which is currently almost not possible to use during periods of excessive energy consumption (winter, night). This main drawback of the solar energy can be very efficiently solved by storing and later evolving of accumulated heat from solar gains according to the day-night as well as the seasonal, i.e. summer-winter cycle. A novel solution described in this contribution is an opportunity to reduce significantly the energy demands for heating/cooling and heating of Domestic Hot Water (DHW). The costs for construction and operation of future buildings are considerable reduced if the heat comfort is maintained by aluminium foam heating/cooling ceiling heat exchangers that allow storage of the heat in the form of latent heat of phase transition of Phase Change Materials (PCMs) impregnated in the porous structure of aluminium foam for later use or, for removal of undesirable heat to the building surroundings during comparatively colder summer nights.