Modeling and Simulation of Photobioreactors with Computational Fluid Dynamics—A Comprehensive Review

The Role of Light on the Microalgae Biotechnology: Fundamentals, Technological Approaches, and Sustainability Issues

Light energy directly affects microalgae growth and productivity. Microalgae in natural environments receive light through solar fluxes, and their duration and distribution are highly variable over time. Consequently, microalgae must adjust their photosynthetic processes to avoid photo limitation and photoinhibition and maximize yield. Considering these circumstances, adjusting light capture through artificial lighting in the main culture systems benefits microalgae growth and induces the production of commercially important compounds. In this sense, this review provides a comprehensive study of the role of light in microalgae biotechnology. For this, we present the main fundamentals and reactions of metabolism and metabolic alternatives to regulate photosynthetic conversion in microalgae cells. Light conversions based on natural and artificial systems are compared, mainly demonstrating the impact of solar radiation on natural systems and lighting devices, spectral compositions, periodic modulations, and light fluxes when using artificial lighting systems. The most commonly used photobioreactor design and performance are shown herein, in addition to a more detailed discussion of light-dependent approaches in these photobioreactors. In addition, we present the principal advances in photobioreactor projects, focusing on lighting, through a patent-based analysis to map technological trends. Lastly, sustainability and economic issues in commercializing microalgae products were presented.

Structured population balances to support microalgae-based processes: Review of the state-of-art and perspectives analysis

Design and optimization of microalgae processes have traditionally relied on the application of unsegregated mathematical models, thus neglecting the impact of cell-to-cell heterogeneity. However, there is experimental evidence that the latter one, including but not limited to variation in mass/size, internal composition and cell cycle phase, can play a crucial role in both cultivation and downstream processes. Population balance equations (PBEs) represent a powerful approach to develop mathematical models describing the effect of cell-to-cell heterogeneity. In this work, the potential of PBEs for the analysis and design of microalgae processes are discussed. A detailed review of PBE applications to microalgae cultivation, harvesting and disruption is reported. The review is largely focused on the application of the univariate size/mass structured PBE, where the size/mass is the only internal variable used to identify the cell state. Nonetheless, the need, addressed by few studies, for additional or alternative internal variables to identify the cell cycle phase and/or provide information about the internal composition is discussed. Through the review, the limitations of previous studies are described, and areas are identified where the development of more reliable PBE models, driven by the increasing availability of single-cell experimental data, could support the understanding and purposeful exploitation of the mechanisms determining cell-to-cell heterogeneity.

Energy Consumption Analysis for Coupling Air Conditioners and Cold Storage Showcase Equipment in a Convenience Store

The energy use intensity (EUI) of convenience stores was substantially higher than that of office buildings and hotels, due to a compact footprint but a high density of equipment yielded a higher EUI. As a result, it is critical to assess and maintain the state of the convenience store in order to obtain a lower EUI and reduce energy consumption. This study utilizes a convenience store to evaluate energy consumption and perform a CFD simulation to see how the environment influences by cold storage showcase (CSS) equipment. On the basis of field testing and on-site web-based monitoring data, a survey of baseline information through data collecting and energy benchmarking data has been provided and extensively examined. According to energy monitoring, the convenience store’s highest electricity use is 23,055 kWh in June, and the lowest power consumption is 15,216 kWh in February. The CFD simulation results revealed that the temperature near the CSS can be 3–5 °C lower than in other regions. The temperature nearby return air will be lower as a result of the low-temperature air impacts from CSS. The AC sensor detects that the environment has met the indoor requirements and performs the load reduction operation. After adjusting the AC temperature, it is discovered that the unit is unable to attain the appropriate temperature. Energy consumption can be reduced, resulting in more energy-efficient AC and CSS operations. Furthermore, the CSS’s cold air effect might be taken advantage of by raising the AC-2 temperature set point to generate energy savings.