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Open Access
Cascaded thermodynamic and environmental analyses of energy generation modalities of a high-performance building based on real-time measurements
(MDPI AG, 2020-04) Al Doury, Raaid Rashad Jassem; Ozkan, S.; Mengüç, Mustafa Pınar; Mechanical Engineering; MENGÜÇ, Mustafa Pınar; Al Doury, Raaid Rashad Jassem
This study presents cascaded thermodynamic and environmental analyses of a high-performance academic building. Five different energy efficiency measures and operation scenarios are evaluated based on the actual measurements starting from the initial design concept. The study is to emphasize that by performing dynamical energy, exergy, exergoeconomic, and environmental analyses with increasing complexity, a better picture of building performance indicators can be obtained for both the building owners and users, helping them to decide on different investment strategies. As the first improvement, the original design is modified by the addition of a ground-air heat exchanger for pre-conditioning the incoming air to heat the ground floors. The installation of roof-top PV panels to use solar energy is considered as the third case, and the use of a trigeneration system as an energy source instead of traditional boiler systems is considered as the fourth case. The last case is the integration of all these three alternative energy modalities for the building. It is determined that the use of a trigeneration system provides a better outcome than the other scenarios for decreased energy demand, for cost reduction, and for the improved exergy efficiency and sustainability index values relative to the original baseline design scenario. Yet, an integrated approach combining all these energy generation modalities provide the best return of investment.
Open Access
Daylighting design process for visual comfort and energy efficiency for a signature building
(IOP Publishing, 2019) Kutlar, Meral Nil; Mengüç, Mustafa Pınar; Mechanical Engineering; MENGÜÇ, Mustafa Pınar
Human comfort is the most important priority in designing living environments. Achieving thermal comfort, visual comfort, effective operation of a building along with innovative energy efficiency measures require extensive involvement of engineers and architectures in tandem for the future high-performance buildings. In this paper, we focus on design of the daylighting aspects of a complicated building and present a methodology. The concept here is based on the interactions of several stakeholders including the project owner, the project architect, structural engineers, façade engineers, mechanical engineers, lighting designers and electric engineers, who are involved in extensive discussions towards the design and construction of a complicated building in a iniversity campus. Simulations are carried out using different architectural and computational techniques including DesignBuilder and Revit. The project constraints set by the stakeholder preferences are resolved with other engineering methodologies. This interactive process allowed a very favourable design of daylighting in the building. In this paper, the steps are discussed and the methodology is outlined.
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Deagglomeration of nanoparticle clusters in a “cavitation on chip” device
(American Institute of Physics Inc., 2020-11-01) Gevari, M. T.; Niazi, S.; Karimzadehkhouei, M.; Sendur, K.; Mengüç, Mustafa Pınar; Ghorbani, M.; Kosar, A.; Mechanical Engineering; MENGÜÇ, Mustafa Pınar
Due to the potential of significant energy release in cavitating flows, early cavitation inception and intensification of cavitating flows are of great importance. To use this potential, we investigated the deagglomeration of nanoparticle clusters with the implementation of hydrodynamic cavitation in a microfluidic device. For this purpose, a microfluidic device with a micro-orifice geometry was designed and fabricated using standard microfabrication processes. The system was tested with distilled water in the assembled experimental setup. The flow patterns were characterized using the cavitation number and inlet pressure. Titania nanoparticles were utilized to prepare nanoparticle suspensions. The suspensions were heated to allow agglomeration of nanoparticles. The system was operated with the new working fluid (nanoparticle clusters) at different inlet pressures. After characterizing flow patterns, the flow patterns were compared with those of pure water. The deagglomeration effects of hydrodynamic cavitation on nanoparticle clusters showed the possibility to apply this method for the stabilization of nanoparticles, which paves way to the implementation of nanoparticle suspensions to thermal fluid systems for increased energy efficiency as well as to drug delivery. Our results also indicate that the presence of nanoparticles in the working fluid enhanced cavitation intensity due to the increase in the number of heterogeneous nucleation sites.
Open Access
Exergy efficiency for radiation heat transfer
(IOP Publishing, 2020) Mohammed, Hayder Noori; Mengüç, Mustafa Pınar; Mechanical Engineering; MENGÜÇ, Mustafa Pınar; Mohammed, Hayder Noori
One of the evaluation criteria for the performance of thermal processes is exergy analysis. Along with energy analysis, exergy calculations provide a clear and highly effective understanding of the performance of a system. Although exergy analysis has been extensively applied to many industrial processes, there are limited works for solar energy conversion systems that include the details of radiation transfer. The use of the Carnot efficiency expressions for calculating the exergy received from the thermal radiation source is questionable because it neglects the directional and spectral aspects of radiation heat transfer. In this study, the exergy efficiency calculations for radiation heat transfer in energy conversion systems are discussed. Comparisons of different expressions for exergy efficiency are presented, and the effects of source and sink temperature variations are explored.
Open Access
Reducing shape errors in the discrete dipole approximation using effective media
(Optica Publishing Group, 2023-12-18) Zhu, Y.; Liu, C.; Yurkin, Maxim A.
The discrete dipole approximation (DDA) simulates optical properties of particles with any given shape based on the volume discretization. These calculations cost a large amount of time and memory to achieve high accuracy, especially for particles with large sizes and complex geometric structures, such as mixed black-carbon aerosol particles. We systematically study the smoothing of the DDA discretization using the effective medium approximation (EMA) for boundary dipoles. This approach is tested for optical simulations of spheres and coated black-carbon (BC) aggregates, using the Lorenz-Mie and multiple-sphere T-Matrix as references. For spheres, EMA significantly improves the DDA accuracy of integral scattering quantities (up to 60 times), when the dipole size is only several times smaller than the sphere diameter. In these cases, the application of the EMA is often comparable to halving the dipole size in the original DDA, thus reducing the simulation time by about an order of magnitude for the same accuracy. For a coated BC model based on transmission electron microscope observations, the EMA (specifically, the Maxwell Garnett variant) significantly improves the accuracy when the dipole size is larger than ¼ of the monomer diameter. For instance, the relative error of extinction efficiency is reduced from 4.7% to 0.3% when the dipole size equals that of the spherical monomer. Moreover, the EMA-DDA achieves the accuracy of 1% for extinction, absorption, and scattering efficiencies using three times larger dipoles than that with the original DDA, corresponding to about 30 times faster simulations.

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