Universiti Teknologi Malaysia

About: Universiti Teknologi Malaysia is a education organization based out in Johor Bahru, Malaysia. It is known for research contribution in the topics: Membrane & Adsorption. The organization has 21644 authors who have published 39500 publications receiving 520635 citations.

An overview on doubly fed induction generators′ controls and contributions to wind based electricity generation

Abstract: Undoubtedly, energy has a significant role in economic growth and technical developments. Renewable energy resources are becoming more important in recent years due to their tremendous contributions to the independence of power generation industry from traditional fossil energy resources. Wind energy has been outstanding among renewable energy resources since continuous harvestable potential on the earth is approximately around 10 6 MW. Concerning the variable nature of wind energy, the variable speed machines, especially doubly fed induction generators (DFIG) are one of the considerations for wind energy conversion systems (WECS). Their implementation in renewable energy conversion systems is dramatically increasing due to their numerous advantages such as low cost and small size, the elimination of external DC source, the ability to produce maximum power under various wind and rotational speeds, the capability of controlling active and reactive power, and the opportunity to employ cheaper and smaller convertors and controllers. This paper is an extensive review of researches in the past 30 years on DFIG. The study starts with describing general perspective on wind energy and commonly used generators in wind conversion. Then it presents more details on DFIGs operational modes, utilizations, their modeling and simulation. It is followed by DFIG control methods and overviews of different employed electrical and mechanical controlling methods. Finally the review on the mutual impact of DFIG on power networks and vice versa, including wind uncertainty, power and frequency stability, power and voltage quality, operation under steady state, dynamic and fault conditions, and protections is given. Based on the review DFIG has advantages in terms of electrical, mechanical, and economic perspectives. It can be concluded that the DFIG has the most promising future for WECSs in power generation to complement the conventional systems.

A review of energy characteristic of vertical greenery systems

Abstract: Rapidly growing cities and human activities change the environment and are accompanied by some drawbacks. Sustainable remedies are needed to protect the environment and the earth against warming environment, pollution, natural resource use and other negative aspects of human activities. Applying vertical greenery systems not only reduce temperature, but also have many economic, environmental and social benefits. This review is about vertical greenery systems description, division and benefits with a focus on energy related topics. The paper describes different experiments on vertical greenery systems by attention to their energy characteristic from recent years. Scan research and studies have determined positive aspects of these sustainable systems as well as a few negative aspects. Moreover, different parameters which are involved in thermal performance of vertical greenery systems are highlighted. Based on various scan research some recommendations for future studies are proposed.

Energy efficiency and low carbon enabler green it framework for data centers considering green metrics

Abstract: The increasing demand for storage, networking and computation has driven intensification of large complex data centers that run many of today's Internet, financial, commercial and business applications. A data center comprises of many thousands of servers and can use as much energy as small city. Massive amount of computation power is required to drive and run these server farms resulting in many challenging like huge energy consumptions, emission of green house gases, backups and recovery; This paper proposes energy efficiency and low carbon enabler green IT framework for these large and complex server farms to save consumption of electricity and reduce the emission of green house gases to lower the effects of global warming. The framework uses latest energy saving techniques like virtualization, cloud computing and green metrics to achieve greener data centers. It comprises of five phase to properly implement green IT techniques to achieve green data centers. The proposed framework seamlessly divides data center components into different resource pools and then applies green metrics like Power Usage Effectiveness, Data Center Effectiveness and Carbon Emission Calculator to measure performance of individual components so that benchmarking values can be achieved and set as standard to be followed by data centers.