Numerical and Experimental Study of Phase Change Around Cold Flat Plate Submersed in PCM

Resumo

The global demand of energy is ever increasing due to the continuous increase of the world population,
industrial growth, transport, cooling and heating and similar activities which are strongly energy or electricity
dependents. During the last decades electricity was mainly generated by combustion of fossil fuels such as coal,
petroleum products and similar energy sources. On a global scale this resulted in huge amounts of greenhouse
gases which led to global warming of the planet with the disastrous consequences that humanity is facing in recent
years including melting of snow in the Poles, increasing water level in oceans, uncontrollable heating and cooling
seasons occurrence and duration and many other uncommon changes. In addition to this, fossil fuels fields are
deemed to be exhausted in the near future which leaves mankind without adequate alternatives for survival. This
possible scenario urged the nations to look for other energy alternatives resources to substitute fossil fuels and at
the same time do not degrade the environment. Solar and wind energy appear at the top of the list of possible
alternatives that are well developed and reasonably easy to implement but suffers from intermittency. To solve
this problem, many energy storage systems and technologies are investigated and developed to improve the
efficiency and widen the acceptability of these systems. One of these energy storage systems is energy storage in
latent heat. In the present study it is proposed to investigate latent heat storage with flat plate geometries using
water as a Phase Change Material (PCM). A model based on pure conduction is developed for the solidification
of PCM between flat cold plates. Experiments were done to validate the model. The wall temperature, spacing
between plates and the material of the plate are found to strongly affect the solidified mass, the interface velocity
and the time for complete phase change.