Farshad Mohammadnejad

Bio: Farshad Mohammadnejad is an academic researcher from Sahand University of Technology. The author has contributed to research in topics: Thermal energy & Packed bed. The author has an hindex of 1, co-authored 1 publications receiving 34 citations.

A CFD modeling and investigation of a packed bed of high temperature phase change materials (PCMs) with different layer configurations

Abstract: In recent years, one of the most important issues is optimization of thermal energy-storing technologies. Using phase change materials (PCMs) with specific phase change temperatures allows us to store latent heat as thermal energy. This is one of the most efficient ways to store thermal energy. The objective of this paper is to investigate the discharge performance of a packed bed filled with multi layers of high temperature encapsulated PCMs through a CFD modeling via Comsol multi-physics software. Results of simulation are compared to results of the experimental researches of the literature and there is good agreement between them. The influence of each layer's height and porosity along with different configurations of the PCMs according to their phase change temperatures (ascending and descending in flow direction) are analyzed. It is observed that increasing the inlet velocity of heat transfer fluid (HTF) and increasing the porosity of layers of PCM in the packed bed have similar outcomes and makes the packed bed deplete more rapidly. Some new configurations are suggested and optimized regarding Δ tutl, which is defined as the ratio between duration of receiving energy with desired temperature to total discharge time of the packed bed, during the discharge process. Results indicate that by setting the layer heights of the PCMs in a descending order and also having the porosity of each layer to decrease in the flow direction, results with 29.2% better performance can be obtained. Optimization of Δtutl can be a defining factor in designing of packed beds and also a concentrating solar power (CSP) plant.

Building heating applications with phase change material: A comprehensive review

Abstract: Energy crisis and environmental problems motive a variety of research strategies to increase energy efficiency, decrease stress on energy infrastructure, and consequently reduce CO2 emissions. Improving efficiency of building heating applications by advanced techniques such as solar collectors and heat pumps, is considered as one research strategy. Utilization of phase change material (PCM) with the virtue of high energy storage density is another research strategy. However, a comprehensive review for intergrating these two research strategies, namely building heating applications with PCM, is still lacking. This study presents a comprehensive review of research works for these applications including PCM roofs, ceilings, and walls, PCM windows, PCM floors, solar chimneys with PCM, solar heating applications with PCM, heat pump applications with PCM, and electrical heaters with PCM. Research development for these passive and active applications including key findings, is sufficiently presented. Summaries and discussions are conducted to identify research gaps for each application. To better utilize the PCM, PCM types, encapsulation forms of PCM, and types of PCM units in these applications are analyzed and discussion. Research methods used in these review literatures are summarized and discussed to further determine research possibilities and limitations. Important conclusions and future recommendations for the research of these applications are given to guide scholars to perform further advances in research.