08-10-2012, 12:22 PM
Energy Management and Conservation
Energy Management.ppt (Size: 1.12 MB / Downloads: 229)
Why Important?
Energy Conservation and its Management has become a prime factor for the nation, society and individual due to high cost and non availability of energy.
Non awareness of latest technologies and methods, non-conventional energy sources and renewable energy sources and how to run the plant and equipment in an energy efficient manner.
Our Concern
Though, energy losses in power distribution equipment including switch gear, transformer, transmission and distribution lines etc are also of our concern, but they are smaller amount as compared to losses in electrical motors used for any drive.
Electrical motors when not selected properly can cause energy losses as high as 25% to 30%. The motors designed in lower frame might not be properly selected and have lower margins when operated at abnormal operating conditions run with very low power factor and efficiency and result in to high losses and consumption
Electrical Drives
The general meaning of a Drive is the system, which is driven by some energy. The source of energy may be any thing like wind, water, oil, steam, solar or electricity etc.
When the source of energy is electricity, the drive is called Electric Drive. In any drive system, we take some output in terms of energy or work done.
Utilization of electricity for driving the mechanical system employs the use of Electric Motors, which gives an output in terms of Mechanical Energy. These electric motors are DC Motors, Synchronous motors or Induction Motors.
Individual motor drive
The machines can be placed in any desired position and can be moved very easily. The machines can be built as an integral part of the complete system, which results in a good appearance, cleanliness and safety. For the purposes where constancy of speed and flexibility of control is required, such as in paper mills and textile industry, individual drive is essential.
Group Drive
By group drive is meant a drive in which a single electric motor drives a line shaft by means of which an entire group of working machines may be operated.
This drive is economical in consideration of the first cost of the motors and control gear. A single motor of large capacity costs less than the total cost of a number of small motors of the same total capacity
The efficiency and power factor of a large group drive motor will be higher, provided it is operated fairly 10% overload when being driven by group drive.
Energy Management
1. A detailed energy monitoring system.
2. Comparison of specific energy consumption values on a
monthly and yearly basis.
3. Exploring possibility of improvement in energy
consumption.
The Energy Audit is carried out to critically examine each of the major energy consuming units to determine whether there exists any unwanted use of energy, losses, idle/redundant running etc. All efforts should be made to run the machine at full/optimum capacity.
Energy Conservation Plan
On identification of areas where electrical energy is not efficiently utilized, remedial measures are to be taken to either replace the old equipment with energy efficient or to implement with energy efficient equipment or to implement modifications to make them more energy – efficient.
Specific energy consumption value is the index to determine how effectively the plant and machinery are utilized in any industrial process. The KWH/ton or KWH/unit of production is calculated in each month and energy consumption indices are worked out separately for major equipment and process. These are then compared on a monthly and yearly basis regularly to detect any deviation from the norm (targeted value) and to take necessary correcting steps.
Observations
From the above table, it can be seen that the efficiency and power factor of Frame 1LA7 710-6 is more than the frame 1LA7 636-6.
The saving in power loss by using 1LA7 710-6 motor is ( 53.6 – 31.66) kW = 21.94 kW. If the motors are running continuously, then the number of unit saved is 24x 21.94 = 526.56 kWh per day per motor or 192194 kWh per year per motor.
Taking the unit charge as Rs 4 per unit; the total saving is Rs 192194 x 4 = Rs 768776.
4. Let us take 15% interest and depreciation. The extra expenditure per year on the cost is 2x0.15 Lakh = Rs 30000. The pay back period is 30000 x12/768776 months = 0.468. It is less than 15 days only. It may be noted that the working hours were taken 24 hours which is not realistic. Let us take 8 hrs per day. The amount saved per year is Rs 768776x8/24 = 256259/-. Therefore payback period is 0.468x3 = 1.4 months.
5. If, there are 1x105 ( 1 Lakhs) motors operating every day, we can save power 21.94 x 1x105 kW = 2194 MW.