Green Rameswaram - Energy Efficiency in Motors
Role of Electric Motors in Energy Efficiency Scenario:
Electricity Usage by the Type of Application:
A typical classification of motor systems by different systems is shown the figure below. Alt-hough the figures may vary from country to country the general pattern is comparable in most countries. Pumping, Compressors & HVAC account for the major portion of the elec-tricity consumption. Material handling and processing could be another big consumer of electrical energy although these systems are quite project specific and have a wide variety of usage patterns. (Source IEA 2015)
The present workhorse of the drive system is the ubiquitous 3 phase induction (AC) motors. In many of the household appliances, the single phase induction motor is often used. Alt-hough there are norms for energy efficiency for most of the above applications, it is the first cost (Acquisition Price) that often determines the purchase decision. Another point to be noted is the fact that the above motors are invariably fixed speed type. But in reality the load requires to be operated at different speeds and the torque requirements at different speeds also vary. Thus in many cases the provision of a variable speed drive system, would often lead to enormous gains in efficiency and result in huge energy savings.
It is also to be noted that more than the motor, it is the design of the total integrated system for pumping, air conditioning, cooling, etc., that is to be optimised. The importance for increased energy efficiency is obvious and is facilitated by the proper choice of the motor, the speed variation, associated piping, heat exchangers, etc. Only then the full potential of energy efficiency can be realised. Often price driven decisions lead to sub-optimal solutions with its attendant inefficiencies.
Another key factor in the use of motor is the starting current that is associated with directly mains operated equipments. Typically induction motors exhibit high starting inrush currents of the order of 4 - 6 times the full load running current. Generally for more than 3 or 5 HP (2.3 or 3.7 kW) motors this inrush current is reduced by star-delta starters. The starting current is cut down by three times with this. But there are other applications in larger size motors which are invariably star connected and hence are started direct online.
The above observations are far more relevant when renewable sources of power are used. It is quite common to exclude even room air conditioners from the circuit in the case of a Die-sel Generator set. The same is the case with solar panels. Such sources of power are often incapable of handling such large inrush currents. The voltage output of such generation sys-tems dips quite a bit during such starting incidents. There are inherent peak current handling constraints in many of the auxiliary sources of energy.
The introduction of sophisticated power electronics enables ‘Soft Starting’ of such motors. This invariable leads to higher costs which are not acceptable to the end user. Even though the maximum demand for commercial and industrial users come down by adopting such techniques, the added first cost becomes an issue.
In the next article we will elaborate on how techniques are used to obtain an optimal life cycle cost solution incorporating renewable energy along with the grid power.
Green Rameswaram project
|1||Archaeology and History||Monograph on Archaeology of Rameshwaram Results of the Archaeological Excavation By REACH Foundation, Chennai|
|2||Solid waste management||Work taken up in 10 wards of Rameshwaram Municipality by Hand in Hand, India, Chennai|
100 nos. of 1 cum Shakti Surabhi plants and 3 nos. of 6 cum Shakti Surabhi Bio-methanation plants installed and commissioned
Provided LED lamps to 200 houses at Dhanushkodi
|4||Rain water haresting||Revived and renovated 20 Traditional water bodies (Teerthams). Another 22 identified and further process started|
|5||Participatory eco-tourism||Pilgrims coming from other states are some times helping in cleaning the areas of Rameshwaram|
|6||Sewage treatment and underground drainage||
Decentralised sewage treatment tried at some places by planting vettiver grass.
TWAD will start the underground drainage work shortly
|7||Social Engineering||Regular awareness camps, eco-camps, Rangoli competitions etc. are held in schools, colleges and different wards with the involvement of the local community|
|8||New merchandise and livelihood opportunity||A few merchandise have been tried such as T-shirts, cotton bags, cups with Rameshwaram logo, caps etc.|
|9||Green transport||Battery operated three wheeler is used by ‘Green Rameshwaram’ project regularly. It is very popular and attracting the attention of the locals as well as outsiders|
|10||Landscaping and beautification||
Forest department have planted 20,000 trees in the Rameshwaram Island with a very high survival rate
Green Rameshwaram project also developed Mangala vanam and planted a few trees near temple and near the renovated teerthas. The process is on..
|11||Marine bio-diversity||Study and collection of endangered species is on..|