Bale V. Reddy

Bio: Bale V. Reddy is an academic researcher from University of Ontario Institute of Technology. The author has contributed to research in topics: Combined cycle & Exergy. The author has an hindex of 27, co-authored 110 publications receiving 2837 citations. Previous affiliations of Bale V. Reddy include University of New Brunswick & Dalhousie University.

Geothermal heat pump systems: Status review and comparison with other heating options

Abstract: Heating is a major requirement in many regions, and growing energy demands and pollutant emissions have allowed unconventional heating technologies to be considered, including geothermal. Geothermal heat pumps are reviewed, including heat pump technology, earth connections, current world status and recent developments. Geothermal heat pump technology and conventional heating systems are compared in terms of costs, CO2 emissions and other parameters. Geothermal heat pump use is economically advantageous when the price of electricity is low. Alternatively geothermal heat pump units have the lowest emissions depending when electricity is produced from a low emitting source.

Performance evaluation of a hybrid photovoltaic thermal (PV/T) (glass-to-glass) system

Abstract: In this paper, an attempt is made to evaluate the thermal performance of a hybrid photovoltaic thermal (PV/T) air collector system. The two type of photovoltaic (PV) module namely PV module with glass-to-tedlar and glass-to-glass are considered for performance comparison. The results of both PV modules are compared for composite climate of New Delhi. Analytical expression for solar cell, back surface, outlet air temperatures and an overall thermal efficiency are derived for both cases. It is observed that hybrid air collector with PV module glass-to-glass gives better performance in terms of overall thermal efficiency. Parametric studies are also carried out.

Performance analysis of photovoltaic systems: A review

Abstract: In this paper, a thorough review of photovoltaic and photovoltaic thermal systems is done on the basis of its performance based on electrical as well as thermal output. Photovoltaic systems are classified according to their use, i.e., electricity production and thermal applications along with the electricity production. The application of various photovoltaic systems is also discussed in detail. The performance analysis including all aspects, e.g., electrical, thermal, energy, and exergy efficiency are also discussed. A case study for PV and PV/T system based on exergetic analysis is presented.

Thermodynamic assessment of photovoltaic systems

Abstract: In this paper, an attempt is made to investigate the performance characteristics of a photovoltaic (PV) and photovoltaic-thermal (PV/T) system based on energy and exergy efficiencies, respectively. The PV system converts solar energy into DC electrical energy where as, the PV/T system also utilizes the thermal energy of the solar radiation along with electrical energy generation. Exergy efficiency for PV and PV/T systems is developed that is useful in studying the PV and PV/T performance and possible improvements. Exergy analysis is applied to a PV system and its components, in order to evaluate the exergy flow, losses and various efficiencies namely energy, exergy and power conversion efficiency. Energy efficiency of the system is calculated based on the first law of thermodynamics and the exergy efficiency, which incorporates the second law of thermodynamics and solar irradiation exergy values, is also calculated and found that the latter is lower for the electricity generation using the considered PV system. The values of “fill factor” are also determined for the system and the effect of the fill factor on the efficiencies is also evaluated. The experimental data for a typical day of March (27th March 2006) for New Delhi are used for the calculation of the energy and exergy efficiencies of the PV and PV/T systems. It is found that the energy efficiency varies from a minimum of 33% to a maximum of 45% respectively, the corresponding exergy efficiency (PV/T) varies from a minimum of 11.3% to a maximum of 16% and exergy efficiency (PV) varies from a minimum of 7.8% to a maximum of 13.8%, respectively.

Second law analysis of a waste heat recovery based power generation system

Abstract: In the present paper the performance of a waste heat recovery power generation system based on second law analysis is investigated for various operating conditions The temperature profiles across the heat recovery steam generator (HRSG), network output, second law efficiency and entropy generation number are simulated for various operating conditions The variation in specific heat with exhaust gas composition and temperature are accounted in the analysis and results The effect of pinch point on the performance of HRSG and on entropy generation rate and second law efficiency are also investigated The second law efficiency of the HRSG and power generation system decreases with increasing pinch point The first and second law efficiency of the power generation system varies with exhaust gas composition and with oxygen content in the gas Approximating the exhaust gas as air, and the air standard analysis leads to either underestimation or overestimation of power plant performance on both first law and second law point of view Actual gas composition and specific heat should be used to accurately predict the second law performance The present results contribute further information on the role of gas composition, specific heat and pinch point influence on the performance of a waste heat recovery based power generation system based on first and second law of thermodynamics

I and i

Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

Renewable energy resources: Current status, future prospects and their enabling technology

Abstract: Electric energy security is essential, yet the high cost and limited sources of fossil fuels, in addition to the need to reduce greenhouse gasses emission, have made renewable resources attractive in world energy-based economies. The potential for renewable energy resources is enormous because they can, in principle, exponentially exceed the world׳s energy demand; therefore, these types of resources will have a significant share in the future global energy portfolio, much of which is now concentrating on advancing their pool of renewable energy resources. Accordingly, this paper presents how renewable energy resources are currently being used, scientific developments to improve their use, their future prospects, and their deployment. Additionally, the paper represents the impact of power electronics and smart grid technologies that can enable the proportionate share of renewable energy resources.

A Review on Photovoltaic/Thermal Hybrid Solar Technology

Abstract: A significant amount of research and development work on the photovoltaic/thermal (PVT) technology has been done since the 1970s. Many innovative systems and products have been put forward and their quality evaluated by academics and professionals. A range of theoretical models has been introduced and their appropriateness validated by experimental data. Important design parameters are identified. Collaborations have been underway amongst institutions or countries, helping to sort out the suitable products and systems with the best marketing potential. This article gives a review of the trend of development of the technology, in particular the advancements in recent years and the future work required.

Review of energy system flexibility measures to enable high levels of variable renewable electricity

Abstract: The paper reviews different approaches, technologies, and strategies to manage large-scale schemes of variable renewable electricity such as solar and wind power. We consider both supply and demand side measures. In addition to presenting energy system flexibility measures, their importance to renewable electricity is discussed. The flexibility measures available range from traditional ones such as grid extension or pumped hydro storage to more advanced strategies such as demand side management and demand side linked approaches, e.g. the use of electric vehicles for storing excess electricity, but also providing grid support services. Advanced batteries may offer new solutions in the future, though the high costs associated with batteries may restrict their use to smaller scale applications. Different “P2Y”-type of strategies, where P stands for surplus renewable power and Y for the energy form or energy service to which this excess in converted to, e.g. thermal energy, hydrogen, gas or mobility are receiving much attention as potential flexibility solutions, making use of the energy system as a whole. To “functionalize” or to assess the value of the various energy system flexibility measures, these need often be put into an electricity/energy market or utility service context. Summarizing, the outlook for managing large amounts of RE power in terms of options available seems to be promising.

Hydrogen as an energy carrier: Prospects and challenges

Abstract: This paper provides an insight to the feasibility of adopting hydrogen as a key energy carrier and fuel source in the near future. It is shown that hydrogen has several advantages, as well as few drawbacks in using for the above purposes. The research shows that hydrogen will be a key player in storing energy that is wasted at generation stage in large-scale power grids by off-peak diversion to dummy loads. The estimations show that by the year of 2050 there will be a hydrogen demand of over 42 million metric tons or 45 billion gallon gasoline equivalent (GGE) in the United States of America alone which can fuel up 342 million light-duty vehicles for 51 × 1011 miles (82 × 1011 km) travel per year. The production at distributed level has also been discussed. The paper also presents the levels of risk in production, storage and distribution stages and proposes possible techniques to address safety issues. It is shown that the storage in small to medium scale containers is much economical compared to doing the same at large-scale containers. The study concludes that hydrogen has a promising future to be a highly feasible energy carrier and energy source itself at consumer level.