Recent initiatives covered in this review can be divided into three broad categories. The first category concerns mathematically describing the spray drying process using a plug-flow model which allows quick what-if evaluations of the process. Intricacies associated with capturing the drying of a range of droplet sizes are discussed. Challenges in adapting the plug-flow simulation approach to counter-current spray drying, which is common in the production of non-heat sensitive detergent powder, was further elaborated. The second broad category features modeling the spray drying process using the Computational Fluid Dynamics technique. A critical review was provided to guide readers on a common dilemma plaguing this area of spray drying modeling. Recent developments in agglomeration modeling in spray dryers are discussed as well. The final part of this review touches on modeling techniques which can be used to predict the development of specific powder qualities. This includes modeling the degree of protein denaturation during spray drying, predicting the characteristics of crystalline type spray dried powder, and determining the properties of the powder surface at the molecular scale.

Detailed analyses of melting processes in phase change material (PCM) glazing units, changes of direct transmittance as well as investigation of refraction index were provided based on laboratory measurements. The main goal of the study was to determine the direct light transmittance versus time under constant solar radiation intensity and stable temperature of the surrounding air. The experiment was conducted on a triple glazed unit with one cavity filled with a paraffin RT21HC as a PCM. The unit was installed in a special holder and exposed to the radiation from an artificial sun. The vertical illuminance was measured by luxmeters and compared with a reference case to determine the direct light transmittance. The transmittance was determined for the whole period of measurements when some specific artefacts were identified and theoretically explained based on values of refractive indexes for paraffins in the solid and liquid state, and for a glass. The melting process of a PCM in a glass unit was identified as a complex one, with interreflections and refraction of light on semi layers characterized by a different physical states (solid, liquid or mushy). These optical phenomena caused nonuniformity in light transmittance, especially when the PCM is in a mushy state. It was revealed that light transmittance versus temperature cannot be treated as a linear function.

The latent heat storage in the layer of phase change material (PCM) exposed to dynamic changes in boundary temperature was investigated numerically and experimentally. The original numerical model of heat transfer with phase change using a mushy volume approach was proposed and validated. The main improvement in the proposed model in comparison to others is that the compaction of the mesh and longitude of the time step were chosen after analysis of its impact in the field of error. The model was tested in the case of thin layer structure of the triple glazing window with one cavity filled with phase change material paraffin RT18HC. The experimental validation was carried out in the climatic chamber under dynamic changes in external temperature (from 10 to 50 °C) in a daily cycle. The highest accuracy was obtained for space discretization of the control volume 1 mm thick (12 CV for 12 mm of PCM layer) and 5 min time step. The obtained RMSE values, although they cannot be directly compared because of the very different approaches to the simulations, show that the proposed algorithm is sufficiently accurate for the assessment of energy storage in the PCM window. Both the simulation and experiment proved that, under specific conditions, implementation of the PCM into the structure resulted in delaying the peak for around 4 h.