PhD Candidate/ Graduate Researcher, UCLA
This project focuses on investigating different mechanisms of power dissipation in piezoelectric fan
Consider a large building or industrial work place. Every year, a large amount of energy is consumed and eventually wasted to cool down the entire area. Normally, the air temperature is lowered to a value less than comfort temperature of the body to remove its humidity. Finally the air is heated and humidified to reach a controlled condition.
This process is very inefficient because first, it cools down the entire area (the whole air in a room, for instance). Secondly, it does not provide personalized conditioning; all the people in a room must experience the same condition, regardless of their personal preference. A Practical solution to this problem, is developing localized wearable air conditioning devices. A potentially effective area for this purpose is a person's feet, since recent researches have proven that the temperature of the feet has a great influence on the quality of the comfort that someone might experience.
Implementing a miniaturized cooling device in a shoe, requires low-power fans. Conventional rotary fans are difficult to scale down and are power inefficient when miniaturized. A novel type of fans, piezoelectric fans, are a promising alternative because of their simpler structures, less noise, and more importantly, their lower power consumption.
We report a combined experimental and modeling study to help elucidate power dissipation mechanisms in piezoelectric fans.
The present work helps improve our understanding of power consumption mechanisms in piezoelectric fans and provide a guideline in optimal fan operating conditions. The result of this work can be utilized to design and manufacture wearable air conditioning devices, which in turn have great impacts on lowering the energy consumption in large buildings.
Abstract: Thanks to the low operational cost and large storage capacity of smartphones and wearable devices, people are recording many hours of daily activities, sport actions and home videos. These videos, also known as egocentric videos, are generally long-running streams with unedited content, which make them boring and visually unpalatable, bringing up the challenge to make egocentric videos more appealing. In this work we propose a novel methodology to compose the new fast-forward video by selecting frames based on semantic information extracted from images. The experiments show that our approach outperforms the state-of-the-art as far as semantic information is concerned and that it is also able to produce videos that are more pleasant to be watched.
Pub.: 16 Aug '17, Pinned: 19 Aug '17
Abstract: The negative environmental impacts of burning fossil fuels have forced the energy research community seriously to consider renewable sources, such as naturally available solar energy. This paper provides an overview of solar thermoelectric (TE) cooling systems. Thus, this review presents the details referring to TE cooling parameters and formulations of the performance indicators and focuses on the development of TE cooling systems in recent decade with particular attention on advances in materials and modeling and design approaches. Additionally, the TE cooling applications have been also reviewed in aspects of electronic cooling, domestic refrigeration, air conditioning, and power generation. Finally, the possibility of solar TE cooling technologies application in “nearly zero” energy buildings is briefly discussed, and some future research directions are included. This research shows that TE cooling systems have advantages over conventional cooling devices, including compact in size, light in weight, high reliability, no mechanical moving parts, no working fluid, being powered by direct current, and easily switching between cooling and heating modes.
Pub.: 13 Jul '17, Pinned: 19 Aug '17
Abstract: Nearly Zero Energy Buildings (nZEBs) represent the backbone to achieve ambitious European goals in terms of energy efficiency and CO2 emissions reduction. As defined in the EPBD, by 31 December 2020, all of the new buildings will have to reach a target of nearly zero energy. This target encourages the adoption of innovative business models as well as the technology development in the building sector, aimed at reducing energy demand and exploiting local renewable energy sources (RES). Assessing the share of implementation and the performance of technologies in new or renovated nZEBs is strategic to identify the market trends and to define design guidelines with the most effective solutions according to the context. In this regard, this paper analyses the construction features of a set of nZEBs, collected in 17 European countries within the EU IEE ZEBRA2020 project, with a special focus on the influence of the boundary conditions on the technologies adopted. The results show a general high insulation level of the envelope and recurrent specific technologies in the Heating Ventilation Air Conditioning (HVAC) system (i.e., heat pumps and mechanical ventilation), while the climatic conditions do not drive significantly the design approach and the nZEB features.
Pub.: 31 May '17, Pinned: 19 Aug '17