Informatics Publishing Limited

Siddhartha Bhatt M. ¹, Rajkumar N. ²

Affiliations
1 Additional Director, Central Power Research Institute, Bangalore - 560 080, IN
2 EO4, ERED, Central Power Research Institute, Bangalore - 560080, IN

Abstract

Indian coals inherently contain low inherent moisture (IM) (5.5-9.5 % with an average of around 7.5 %) and moisture addition is through the surface moisture (SM) due to sources external to the coal. On the other hand imported coals contain very high IM (15-25 %) but negligible SM. Presence of surface moisture (SM) is a major liability to the power generating process and it’s and control needs to be understood on a broader national perspective. Great importance must be given during the transportation, handling, transfer and storage of coal to ensure that its heating value is preserved and there is no deterioration on account of SM addition enroute to the power plant or in the coal yard storage prior to its entry into the furnace of the boilers. It is the SM which affects the power plant operations. In the case of imported coals higher total moisture (TM) coals (higher inherent moisture and almost no SM) are cheaper and the marginally increased generation cost due to IM is offset by the cheaper purchase price. The same is not true for Indian coals where there is no provision for cost accounting of SM except for upper limits. The impact of 1 % TM (without considering the weight effect) is -4.2 kcal/kWh on design unit heat rate, -8.2 kcal/kWh on operating unit heat rate, -0.0226 p.u. of plant load on Station load, -4.0 % on Plant load factor,+0.2263 % of plant load on Auxiliary power, +0.0079 kg/kWh on Specific coal consumption,+1.1426 ml/kWh on Specific fuel oil consumption and +15.21 kcal/kWh on Station heat rate.

Keywords

Moisture in Coal, Surface Moisture, Inherent Moisture, Total Moisture, Gross Calorific Value, Unit Heat Rate

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Sudhakar H. S. ¹, Indira M. S. ², Gujjala B. Balaraju ³, Siddhartha Bhatt M. ⁴

Affiliations
1 Junior Research Fellow, EATD, Central Power Research Institute, Bangalore-560080, IN
2 Principal, Sir M Visvesvaraya Institute of Technology, Bangalore-562 157, IN
3 Electrical Appliances Technology Division, Central Power Research Institute, Bangalore-560080, IN
4 Energy Efficiency and Renewable Energy Division, Central Power Research Institute, Bangalore-560080, IN

Abstract

Performance of a SPV system is dependent on temperature, array configuration, solar insolation, shading etc. The conversion of solar energy using SPV modules,change in insolation conditions which severely affect the efficiency and output power of the modules. Improvement in the efficiency of conversion of solar energy can be done by tracking the maximum power point of a PV module. Various types of MPPT charge controllers are available in the market. A dc-dc converter is an important component of a SPV system as it acts as an interface between the load and the SPV module. These dc-dc converters enhance the performance of the MPPT algorithms leading to an improvement in the overall efficiency of the SPV system. This paper presents the modeling and simulation of one diode equivalent circuit of solar photovoltaic module using MATLAB/SIMULINKTM along with the boost converter which gives an efficiency of 93.29%.

Keywords

Maximum Power Point Tracking (MPPT), Solar Photovoltaic (SPV) Characteristics, Boost Converter

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Siddhartha Bhatt M.

Abstract

This paper presents the study of energy efficiency improvements of central air conditioners (AC) through the optimal integration of natural air ventilation functions. There is potential for energy saving through the shifting to mixed mode air conditioning invoking the ambient energy for cooling. An optimization study shows that up to an ambient temperature of 22˚C, passive cooling can be used and beyond that temperature active cooling is required. Simulation of energy consumption for air condition has been undertaken in 5 major cities of India, viz., Bengaluru, New Delhi, Mumbai, Kolkata and Chennai. The energy efficiency specified as per ECBC (energy conservation building code of India) is 80-90 kWh/m²/year for AC and can only be reduced through passive cooling components. Results indicate that it is possible to reduce the energy consumption by almost 50% through the use of natural air ventilation cooling.

Keywords

Air Conditioning, Mixed Mode AC, Ventilation Air Cooling, Passive Systems, Evaporative Systems, Energy Efficiency

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Siddhartha Bhatt M. ¹

Affiliations
1 Energy Efficiency & Renewable Energy Division, Central Power Research Institute, Sir CV Raman Road, Bangalore-560080, IN

Abstract

This paper presents a review of the energy efficiency in solar photovoltaic (SPV) systems with special reference to quantification and improvement of non-module system efficiency. The system efficiency (also called as performance ratio) is composed of photopic efficiency (losses in light energy before actually interacting with the SPV cell surface) and electrical efficiency (losses in electrical energy output generated by the module and before it is used by the load). Non module system efficiencies of operating SPV plants range between 54.93 % to 70.16 % with an average value of 62.32 % and standard deviation of 4.57 %. System efficiency considerations are important in design of power plants for given end user loads. If the calculations are on the basis of kWpeak, a typical 100 kWpeak system gives a peak output of 50-65 kW at the load point due to system efficiency and also lowering of module efficiency due to non-standard operating conditions. System efficiency excludes auxiliary power (2-4 % of the generated power), losses in battery (~20 %) due to storage component loss of energy generated due to non-availability of the grid (for grid tied systems) and stochastic incident radiation loss (~16 %). System efficiency presents possibilities of improvement to 75-80 % level through improved system design and improved operation and maintenance practices.

Keywords

Solar Photovoltaic, System Efficiency, Photopic Efficiency, Electrical Efficiency, Module Efficiency, Stochastic Efficiency.

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