Energy Audit: Case Study of a Wheel Manufacturing Industry

Energy Audit: Case Study of a Wheel Manufacturing Industry

Highligting the Energy Conservation Opportunities in the Manufacturing Sector

Manu Sharma

Department of Electrical Energy and Power University of Petroleum and Energy Studies Dehradun, India

V Anish Koushik Department of Electrical Energy and Power University of Petroleum and Energy Studies

Dehradun, India

Abstract Increase in energy demand globally has forced the energy cost to rise up. One of the major sectors which are responsible for the high energy consumption worldwide is industrial sector. Developing countries like India, Bangladesh, and Pakistan etc are having huge imbalance between the demand and supply of electricity. To drive the growth of nation it is must to reach at the balance point in demand and supply. In industrial sector, commercial buildings we have higher consumption pattern observed, that can be reduced by implementing Energy Conservation Measures. The typical features of any typical industry is determined by the quantity and type of raw materials, its production technology, organization of technical equipment and level of automation. All The above factors add to variation in the using up of special energy carriers. This paper throws light over the consumption of energy profile of a typical wheel rim manufacturing plant. It describes technical, maintenance as well as economical factors that can be applied in a comprehensive analysis to achieve energy efficiency in the confectionery industry to assist the choice of the best available technology.

II. ENERGY SCENARIO IN INDIA

Availability of power has a critical role in economic development as well as overall enhancement of lifestyle of the country. India stands fifth in the world for the energy demand. The installed capacity of India is 255 GW. The breakup of this generation from different sources is:

1. Thermal (Coal, Gas, Diesel) – 177 GW [1].

2. Nuclear- 4780 MW [1]. 3. Hydro- 40798 MW [1].

1. Renewable sources- 31692 MW [1].

   7

   The annual electricity generation of our country in last two decades has seen a growth of 191 GW, from 66GW in 1991 to 255GW in 2014. In India breakup of demand as per sector is:

   9

   Industrial

   21

   35

   1. INTRODUCTION

The main aspect of the non structural approach to the energy conservation is about change in human behavior. The definition of the behavioral change for the energy conservation according to the dictionary of energy is the change in the daily activities of a person in the individual or as whole organization that reflect the commitment towards the energy conservation.

Human activities are an essential factor in conservation of energy. It not only leads to the financial benefits for an organization but also proves as the best practice to trim down the gap between demand and supply.

Many researchers have reported that individual effort for the conservation of energy is the best method to reduce the electricity deficit in India. Energy conservation can be defined by reducing the energy demand without making any sacrifice in the production quality and working output of any organization or unit.

28

Domestic

Agriculture Commercial Miscelleneous

Fig. 1. Energy consumption in main sectors

From the above figure it is observed that industries are the major consumption areas of electricity. So it is essential for us to concentrate on the energy intensive sectors and try to improve the performance of them to conserve energy. This paper mainly focuses on the energy intensive industry. The case study of an industry is dicussed in the later chapters which will give a brief idea of how much savings can be achieved in an industry. The potential of energy conservation options, which provides savings to the consumer, utility and society as well, has, therefore, to be fully extracted [2].

1. Introduction to Energy Audit

   An energy audit is a survey, inspection and analysis of energy flow to conserve energy in an industry, it is a process to reduce the amount of energy consumed within the industry without

   negatively affecting the output. According to national energy conservation laws and regulations for energy consumption, investigation and energy audit management [3].

   Energy Audit activities in general order includes:

   • Classification of all energy systems

   • Assessment of conditions of the systems

   • Analysis of impact of enhancement to those systems.

   • Preparation of energy audit report and recommendations to improve the energy efficiency of the particular industry.

   All the economic and energy conservation measures recommendations are made once the whole energy data is gathered and audit is done. In developing countries like India we are emphasizing more on the increase in the installed capacity of the country, rather than that we should focus more on the energy conservation methods that will reduce the energy deficiency in India up to a great extent. Researchers and their studies have revealed that energy auditing and management can save India Rs.1800 crore per annum as there is a big prospective to save energy in industrial, commercial as well as corporate buildings. In requisites of electricity, these saving are equal to installation of 5250MW.

2. Types of Energy Audits

   The energy auditing course would provide positive results in drop of energy billing cost for which apposite protective and cost efficient maintenance and quality control programmes are necessary leading to better manufacturing and economic utility activities. We can mainly classify energy audit into three main phases:

   • Phase I- Preliminary energy audit

   • Phase II-General energy audit

   • Phase III- Detailed energy audit [4]

1. INTRODUCTION ABOUT THE PLANT

   A typical wheel rim manufacturing plant is one of Indias leading HCV (Heavy Commercial Vehicles) manufacturer offering transport solutions for a new competitive age in Indias fast- growing economy.

   Its product range covers the full range of heavy-duty applications in mining, construction, power, petroleum, roads and highways, other infrastructure projects and general cargo transportation.

   Fig. 2. Single line diagram of the Plant

   1. Products Manufactured by the plant

      It manufactures component for the automotive and general engineering industries. The company manufactures world-class wheel rims for cars, trucks, tractors and several other vehicle

      categories. It also manufactures skin panels, inner panels and compressor shells.

      Wheel rims:

      It is one of the India's largest single-location facilities for wheel rim manufacturing, with an installed capacity of 15 million wheel rims per year for a range of automobiles.

      Press shop (stampings):

      Its press shop caters to the needs of a diverse range of industries. Clients include automotive, white goods and general engineering companies. Its state-of-the-art press shop can shape 100,000 tonnes of products per annum.

   2. Components of production cost

      Production cost can be broken down into various components which contribute significantly in the overall cost. These are primarily the energy and material costs. The energy cost components in manufacturing the finished are as follows:-

      • Power Supply From Grid

      • Power generation through DG set

      • Compressed Air

      • hilled Water

      • Hot water

      • Water

      • Lighting & Illumination

   3. Energy Guzzlers in the plant

      So . No	Unit	Consumption In kWh
      1	Car line – 1	23711
      2	Car line – 2	88095
      3	Car line – 3	7546
      4	Utilities Car	14781
      5	Tractor Line	23082
      6	Utilities Tractor	14781
      7	Wheel Testing & AC – Car & Tractor line	2096
      8	Plant lighting & AC – Car & Tractor lines	22037
      9	TR losses & Meter Difference car & Tractor lines	16106
      10	Truck Line	138690
      11	Utilities – Truck line	42233
      12	Plant Lighting & AC – Truck Lines	10343
      13	TR losses & Meter Difference – Truck line	8964
      14	Paint Plant – 1	62227
      15	Paint Plant – 2	102312
      16	Utilities – Paint shop	12848
      17	AACL Admin	16578
      18	AACL Canteen	8252
      Total kWh		614682

      Large amount of energy in above mentioned forms are used in the plant. These can be further classified into various equipment. These are termed as Energy Guzzlers. Following table gives the energy consumption of Energy Guzzlers in the plant

      TABLE I. ENERGY CONSUMPTION IN THE PLANT

      Max. Billable Demand

      Max Demand

      Demand(KVA)

      The electricity bills for the last one year were provided by the plant. They were analyzed to see if there can be any savings that can be achieved. Some graphs were plotted as a part of analysis and they are:

      Demand Pattern

      10000

      8000

      6000

      4000

      2000

      0

      Contract Demnad

      1 3 5 7 9 11 13 15

      Months

      Consumption and Charges

      Fig. 3. Demand Analysis of the plant

      Energy consumption and charges

      2500000 10000000

      9000000

      2000000 8000000

      7000000

      1500000 6000000

      5000000

      1000000 4000000

      3000000

      500000 2000000

      1000000

      0 0

      Jan-13 May-13 Aug-13 Nov-13 Mar-14 Jun-14 Sep-14

      Months

      kWh Consumption Energy Charges

      Fig. 4. Energy consumption and charges

   4. Compressed Air

   Demand

   There are total 4 compressors installed in the plant to cater the compressed air requirement of the plant. All compressors are connected in a ring system. Compressed air required for the pneumatic applications of the machines. Set pressure points for the plants are 5.9-6.8 bars. Details of all compressors are as follows:-

   Performance Analysis of Chillers
   S.No	Chiller no.	Flow rate(l/h)
   1	Chiller (carline 2)	13270
   2	Chiller (Paint Shop 2 )	44580
   3	Chiller (Paint Shop 1)	NW
   4	chiller ( truck line )	17800

   TABLE III. CHILLER DETAILS

   F. Lighting and AC load

   The lighting & AC load inventory of entire plant is as follows:

   Area Wise Lighting and Ac consumption

   Press Shop

   New Wheel Rim

   27% Area

   28%

   Press Shop Old 16%

   Truck Line paint shop area

   29%

   Fig. 5. Lighting and Ac load details

   Lighting load of the plant is 290 kw, while AC load used for office cooling is 47 Kw.

2. ENERGY CONSERVATION AND RECOMMENDATIONS

   After thorough analysis, calculations and trial runs (during audit), following energy conservations opportunities have been identified:

   A. Reduction in Contract Demand

   10000

   8000

   6000

   4000

   2000

   0

   The contract demand of the plant was observed to be more as the max demand of the plant never crossed 6000KVA as observed from the electricity bills. So it was recommended to reduce the contract demand to achieve a saving of Rs 47.53Laks/annum.

   Reduction in contract demand

   Sr no	Description	capacity (kW)
   1	Air compressor 1	160
   2	Air compressor 2	160
   3	Air compressor 3	90
   4	Air compressor 4	90
   Total		500

   1 2 3 4 5 6 7 8 9 10 11 12 13

   Months Contract Demand (kVA)

   Minimum Billable Demand (kVA) Max Demand (kVA)

   E. Chillers

   TABLE II. AIR COMPRESSOR DETAILS

   Chilled water is used for the Machine cooling, product cooling. Each section is equipped with the separate Chiller. Required chilled water temperature for the machines is in the range of 14 –

   16. There are total 9 chillers installed in the plant out of which only 4 were working and rest all were stand by

   Fig. 6. Reduction in contract demand

   1. Savings by arresting Leakages in compressor

      Leakage test was done on the compressors to see if there is any leakage and basic analysis was done to quantify the savings that can be achieved by reducing the leakage.

      By arresting the leakages of compressed air system, a saving of Rs 22.99 Lakhs/annum can be achieved.

      Energy savings by Leakages arresting
      S.No	Parameters	Unit	CP3
      1	Loading Time(T)	Min	1.15
      2	Unloading Time	Min	0.94
      3	FAD(Q)	m³/min	25.66
      4	Leakage @ 1 compressor running	%	55%
      5	Allowable leakage	%	10%
      6	Leakage quantity(q)	m³/min	11.5
      7	Motor Power Consumption	KW	165.0
      8	Leakage quantity per day	m³/day	16625.0
      9	Specific power for air generation	KWH/m³	0.107
      10	Energy Lost due to leakages/day	KWH/Day	1782.0
      11	Energy Lost in a year(@330 days)	KWH/Year	534600
      12	Average unit price	Rs	4.3
      13	Monetary Saving by arresting leakages	Rs/annum	2298780
      14	TOTAL SAVING	Lakh/annum	22.99

      TABLE IV. COMPRESSOR LEAKAGE SAVINGS

   2. Savings in Chiller Plant

      Energy Savings By Use of Two Separate Tanks
      Parameter	units	1	2
      Chiller no.	Nos.	chiller1 (Butt Welding)	Chiller 2 (Truck Line)
      Flow rate	Lts/h	13270	17800
      Water Temp in	OC	21.9	20.1
      Water Temp out	OC	20	19.1
      Refrigeration Effect	Tonnes (TR)	8.34	5.89
      Actual power drawn	kW	15.00	17.24
      Expected SEC	kW/TR	1.80	2.93
      Total kW reduction	kW	3.2	3.4
      Total	kW	6.6
      Operating Hours	h	7920
      Annual Energy Savings	kWh/ann um	52324
      Annual Cost Savings	Rs/Annu m	224994
      Total Investment	Rs	4

      It is recommended to use different insulated tanks for storing chilled water out from chillers and the water out from the process. Currently the water from chillers and process is getting mixed in the storage tank. This is reducing the effectiveness of the chillers. Separating the tanks would increase the loading on chillers resulting in improved efficiency and reduced Specific energy consumption of the chillers.

      TABLE V. ENERGY SAVINGS IN CHILLER PLANT

   3. Lighting Savings

      Present Scenario:

      Total Number of Incandescent lamps= 1002 Wattage of lamps= 250W

      Running hours/day= 12

      Total numbers of working day= 365

      Energy Consumed= Lamps*Wattage*Running hours

      =1002*250*365*12

      =1097190 kWh/annum (1)

      Conventional incandescent lamps have life span of one year or so while LED is having lifespan of 5-6 years and consumption of electricity is very less in comparison of conventional lamps [5].

      After Savings:

      We can install LEDs in place of Incandescent lamps: Total Number of LEDs lamps= 1002

      Wattage of LEDs = 120 W Running hours/day= 12

      Total numbers of working day= 365

      Energy Consumed= Lamps*Wattage*Running hours

      =1002*120*12*365

      =526651.2 kWh/annum (2)

      Total Savings= (1)-(2)

      = 1097190-526651

      =570540 kWh/annum (3)

      Average cost of Unit= 4.3/ kWh (4) Total Savings = (3)* (4)

      =24.53 Lakhs/annum

3. CONCLUSION

   A prominent quote Energy saved is Energy generated. It says that we can meet the demand and supply balance either by generating more electricity or by taking suitable measures to increase energy efficiency of the system. As the demand for power is endlessly increasing and putting pressure on the power utilities companies to raise the capacity to meet the load demand. With having this aim we have elaborated a case study of an industrial unit for the reason that industries are the major energy consumers. The data which is being provided in this paper shows that how we can save electricity by correcting some changes in the system and building it energy efficient. The Indian government should make it obligatory for every industry in the country to conduct independent energy audit.

   Benefits of Energy Conservation [6]:

   1. Reduction in the energy consumption and its cost

   2. Capacity of the grid increases without investment

   3. Conservation of natural resources

   4. Reduction in Green house gases and Global Warming

   5. Energy Security of the nation

4. REFERENCES

1. All India region wise generating installed capacity of power Central authority ministry of power, Government of India. November 2014.

2. Zhang Jian, Zhang Yuchen, Chen Song, Gong Suzhou; How to Reduce Energy Consumption by Energy Audits and Energy Management Issue Date: July31 2011- Aug.2011 on page(s): 1 – 5 Date of Current Version: 12 September 2011.

3. Gard Analytics, Energy, Economic and Environmental Research, www.gard.com.

4. Ashok S, Energy Conservation Why Elevated now to the Top of Pyramid? Ashok S, Electrical India, Vol. 53, No. 11, November, 2013, page no. 54 to 60.

5. Fritz W.L.O and Kahn M.T.E., Energy Efficient Lighting System

   Journal of Energy, Vol.17 No. 4, November 2006

6. Mr.Siddharth Bhatt, The inter relationship Between Energy Efficiency Energy Consumption in the Electrical Sector, Electrical India, December 2012, Vol 52, No.12 page no. 192 to 202.