Green Rameswaram - An Initiative by VK Nardep to Make Rameswaram Clean and Green

Newsletter :: February 2016

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Green Rameswaram - Energy Efficiency in Motors


Role of Electric Motors in Energy Efficiency Scenario:

Out of the total electricity consumption in the world, about 60 ~ 65% is accounted by electric motor systems. In industry the figure is closer to 70%. Considering the fact that electricity accounts for 40% of the total emissions, the role of electric motors and its increased efficien-cy is evident in containing the global warming.

In homes, electric motor driven appliances like Fans, Refrigerators, Air Conditioners, Pumps and other appliances like Mixer/Grinder, Washing Machine account for about 60% of the electricity consumption. If offices and commercial complexes it is mainly the air conditioners and fans that is important. In Industries electric motor drives the core industrial processes like machine tools, power presses and pumping systems and auxiliary processes like hydraulic actuators and compressed air generation equipments. In Agriculture the role of pumps for water extraction is obvious. Similarly in public utilities special pumps for water purification, sewage pumps, etc., the role of the motors are quite substantial.

In many of the coastal cities and towns, the HVAC (Heating, Ventilation and Air Conditioning) consumes nearly half of the electricity that is used. And with increased development and improvement in living conditions the ubiquitous electric motor, often termed as the workhorse of the industry, would occupy a central place in the scheme of achieving energy efficiency. Unfortunately in India most of the efforts to achieve energy efficiency is directed towards lighting loads. This is obvious from the evolution of more efficient lighting systems starting from the Edison’s incandescent lamp toward florescent lights (Called tube lights in common man’s language) leading to CFL and LED lighting systems.

It is only recently that the country has woken up to the potential energy savings through the increased efficiency of electric motors. Still market failures and barriers like lack of capital, higher initial costs, reluctance of the plant managers and businessmen hamper the invest-ment in energy efficient motor systems and appliances. Several countries are now establish-ing MEPS (Minimum Energy Performance Standards) which specifies minimum efficiency norms of electric motors and motor based equipments. Developed countries go beyond ad-dressing just efficiency of the motors and use a system optimisation approach to arrive at the best energy management techniques of the system as a whole. Such systems look at the total life cycle costs in holistic fashion rather than the first cost of acquisition and installation.

The dilemma is much more in the third world countries the access to capital often necessi-tates that the used motors are rewound and reused. The poor quality of rewinding often re-duces the efficiency and increase the life cycle costs. Shortage of trained manpower also results in poor maintenance of motors and motorised equipments over their life cycle. But in a constrained economy such as ours, it makes more sense to invest in energy efficient motor systems so that the overall life cycle cost is reduced.

The government also needs to play a proactive role in promoting energy efficiency in a holis-tic manner by introducing mandatory norms or labelling for several motorised equipments, upgrading them periodically and giving fiscal and monetary incentives for energy efficiency equipments.

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

Consolidated Report 

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
3 Renewable Energy

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..


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