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Energy Efficiency in Electrical Utility
Note: i) Attempt any five questions.
ii) All questions carry equal marks.
What is Electricity Tariffs? How is electricity tariff calculated? Also explain the types and factors affecting the electricity tariffs. 7
An industrial plant is operating at 500 kW and maximum demand of 620 kVA. The facility has a power contract based b kVA demand charges, which shall reduce as the power factor is improved. The demand charges rates have been fixed @ ₹7.00 per month per kVA. Determine the savings possible by improving the power factor along with the payback period of putting any investment on power factor correction. 7
Explain the best location for capacitors banks for power factor improvement from energy conservation point of view. Why? Also explain the various method for power factor improvement. 7
A 80 kW induction motor with 80% present full load efficiency is being considered for replacement by a 85% efficiency motor. What will be the savings in energy if the motor works for 7000 hours per year and cost of energy is Rs. 7.50 per kWh? 7
What are the factors to be considered while selecting motor for a particular application? How can you improve the efficiency of a motor under low load condition? Substantiate your answer with a typical case analysis.
What causes air compressor inefficiency? How can we achieve energy efficiency in compressed Air system?
A reciprocating V belt driven compressor was found to operating during normal factory operation with the following parameters:
Load pressure = 7 bar
Unload pressure = 9 bar
Unload time = 4 minutes
Load time = 2.5 minutes
Suggest possible energy saving opportunities on a short-term basis. 14
What is Vapor absorption refrigeration system? Also explain working principle, types and comparison with vapor compression system. 7
A vapor compression system using R12 works between -25°C and 45°C as evaporator and condenser temperature respectively. Using P-H chart determine: 7
i) COP
ii) Mass flow of refrigerant per TR
iii) Piston displacement per TR using volumetric efficiency 80%
iv) Heat rejected in the condenser per TR
v) Ideal COR
Explain the pumps and pumping system performance evaluation and efficient system operation. Also discuss about the various types of pumps and pumping system, characteristics and applications. 7
What are the different types of illumination sources and energy efficiency? Explain the step-by-step approach for assessing energy efficiency of lighting system. 7
What is the role of an energy manager/auditor for energy efficiency in DG plants of an industrial unit? Draw a typical energy balance of a DG Set. 7
What is energy performance assessment of DG Sets? Also discuss about the factor affecting waste heat recovery from DG sets. 7
What is the principle of vapor-compression refrigeration cycle? Explain difference between vapor compression refrigeration system and vapor absorption refrigeration system. 7
Explain the flow control strategies and energy conservation opportunities assessment of Fans and blowers. 7