ENERGY EFFICIENCY IN MATO GROSSO DO SUL / BRAZIL INDUSTRIES CASE ESTUDIES

ENERGY EFFICIENCY IN MATO GROSSO DO SUL / BRAZIL INDUSTRIES CASE ESTUDIES Amâncio Rodrigues da Silva Júnior, Saulo Gomes Moreira, Wellington Rocha Araújo, Diego Bueno Angelo Laboratório de Eficiência Energética, Departamento de Engenharia Elétrica, Universidade Federal de Mato Grosso do Sul UFMS. Campus Universitário, Caixa Postal 549, CEP 79.070-900 Campo Grande-MS, Brazil. eficiencia@del.ufms.br Abstract The subject energy efficiency is present in strategies calling for industries and society. The trouble with the concepts involved in reduction of the costs, improvements in processes and optimization in the industries are inwardly related with electrical energy. This work presents actual cases, in industries in the state of Mato Grosso do Sul, the ones which present points of electric inefficiency, mainly relative to motor systems, and it determines solutions that provide energy gain or reduction of the inefficiencies. Keywords: Energy Efficiency, Motor Systems. 1. Introduction Based on a scenario that is a result of a recent energetic crisis, the Brazilian government has demanded from consumers and electric companies efforts to reduce electric energy waste. To reach this primary objective is the goal of PROCEL National Electric Energy Conservation Program, which is a federal government program under responsibility of the Mines and Energy Ministry and executed by Eletrobrás. The industrial efficiency program of Eletrobrás/PROCEL was used to make accords with institutions interested in attend consumers and agents related to the energetic sector. In the state of Mato Grosso do Sul (MS), supported, initially, by the accord of both financial and technical cooperation between Eletrobrás and FIEMS MS State Industrial Federation, were realized training of qualification and dissemination agents, which would perform energetic diagnosis in industries all over the state. In this article, as a result of some energetic diagnosis performed, some situations where electric energy waste were detected are highlighted, in example, over sized motors in motor systems, pulley disarray and bad motor-load coupling. After the training of the qualification agents, even before the end of the energetic diagnosis process, an accord between Eletrobrás and UFMS Mato Grosso do Sul Federal University, was made, which objective was to establish the LEESM Energetic Efficiency in Industrial Motoring Systems Lab, which intend to became the reference on energetic efficiency studies for industrial consumers in the state, promoting researches and diffusing knowledge in this subject. 2. Global Visions of the Industries The four industries commented in this article, simply named as A, B, C and D, work in three different kinds of activities. Industry A works with industrialization and commercialization of wood manufactured products in Campo Grande-MS, for exportation (United Kingdom, Europe and USA) and internal market supply (except North region of the country). The second one, named industry B, works in the development and production of plastic food packs, it is also located in Campo Grande-MS and commercialize its products in the internal Brazilian market. Both C and D industries work in industrialization and commercialization of clay manufactured products, which are commercialized in the state of Mato Grosso do Sul only. 3. Applied Methodology and Collected Data The objectives of an energetic diagnosis are to quantify the means of energy economy, demand improvement and the investment needed to achieve them. The following procedures were settled: 1) Load quantification of the sectors with the highest consume level; 2) Verification of these loads functioning time per month; 3) Voltage, current and power

measurement; 4) Identification of nameplate parameters of the analyzed equipments; 5) Technical analysis of those equipments; 6) Economical analysis of solutions pointed in technical analysis. One of the equipments utilized for data collection is the EMBRASUL energy analyzer, RE2000 model, which measures and registers electrics parameters such as voltage, current and power. Other equipment utilized was a digital tachometer, for rotor speed measurement to evaluate their loading in relation to their real load (another useful tachometer function is to evaluate bad coupling losses in pulleys and belts). BDMotor (Motors Database) software version 3.0 was utilized to perform an analysis of the motor systems dimensions, based on field collected data. BDMotor software provides energy economy in three-phase induction motors, it is developed by Eletrobrás/PROCEL and CEPEL Eletrobrás System Enterprise and CATE Efficient Technologies Application Center. The database consists of parameters collected in WEG, EBERLE and KOHLBACH dimensions charts. This version of the software consists of 1989 registered motors. Motor systems analyses were performed with high efficiency or standard motors (just in case of over sized motors). 3.1 Industry A In Industry A data were collected from two exhaustion systems, two air compressors, finishing system and squaringup system. Some of this information is listed below. Table 1. Exhauster 1 nameplate, collected and measured data Exhauster 1 Manufacturer: Motores Bufalo S/A Ind. e Com. Rereeled: Yes (3 times) Frame: 13261 No.: 714308 Class: B S.F.: 1 Isol.: B; Reg. Continuous Voltage: 380/660 V - Three-phase - Frequency: 60 Hz Power: 50 cv Current: 77/44 A Nominal RPM: 1750; Measured RPM: 1783 Pulley 1: 1783 RPM - 11,5 cm Diameter; Pulley 2: 823 RPM - 24,2 cm Diameter Disarray: 10º Pulley 1 Tangential Speed: 10,74 m/s ; Pulley 2 Tangential Speed: 10,43 m/s Figures 1 and 2 presents, respectively, active power input and single phase currents input exhauster curves. 40 140 35 120 30 100 Input Power (kw) 25 20 15 10 Current (A) 80 60 40 20 5 0 0 13:48:00 13:51:20 13:54:40 13:58:00 14:01:20 14:04:40 14:08:00 14:11:20 14:14:40 14:18:00 14:21:20 14:24:40 14:28:00 14:31:20 14:34:40 Hour 14:38:00 14:41:20 14:44:40 14:48:00 14:51:20 14:54:40 14:58:00 15:01:20 15:04:40 15:08:00 13:48:00 13:51:17 13:54:34 13:57:51 14:01:08 14:04:25 14:07:42 14:10:59 14:14:16 14:17:33 14:20:50 14:24:07 14:27:24 14:30:41 14:33:58 14:37:15 14:40:32 14:43:49 14:47:06 Hour Phase A Phase B Phase C 14:50:23 14:53:40 14:56:57 15:00:14 15:03:31 15:06:48 Figure 1. Exhauster 1 input power Figure 2. Exhauster 1 input currents

The finishing system has two motors, named sander discs motor and finishing motor. They are shown in table 2. Figure 3 shows the power input in air compressor 1, which feature data is shown in table 3. For the other loads were done the same procedures already presented. Table 2. Sander nameplate, collected and measured data Sander Motor Finishing Motor Manufacturer: WEG Manufacturer: WEG Standard High Efficiency Rereeled: No Rereeled: Yes (Once) IP55 IP54 Current: 42,8/24,7 A Current: 29/17 A Voltage: 380/660 V Voltage: 380/660 V Power: 30 cv Power: 20 cv - Reg.: S1 - Class: N Phases: Three-phase Phases: Three-phase S.F.: 1,15 S.F.: 1,15 Frequency: 60 Hz Frequency: 60 Hz Nominal RPM: 1765 Nominal RPM: 1760 - Ip/In: 8,3 - Weight: 111 kg Measurements Measurements No Load Current: 15 A No Load Current: 10,5 A No Load Power: 2,8 kw No Load Power: 2,1 kw Load Current: 46 A Load Current: 40 A Table 3. Air compressor 1 nameplate, collected and measured data Air compressor 1 Manufacturer: EBERLE Standard / IP54 Reg.: S1 Class.: H Isol.: F Voltage: 380/660 V Power: 30 cv Phases: Three-phase Frequency: 60 Hz Current: 44/25 A Nominal RPM: 1755 Ip/In: 8,6 20 18 Input power (kw) 16 14 12 10 8 6 15:20:48 15:21:50 15:22:52 15:23:54 15:24:56 15:25:58 15:27:00 15:28:02 15:29:04 15:30:06 15:31:08 15:32:10 15:33:12 15:34:14 15:35:16 Hour 15:36:18 15:37:20 15:38:22 15:39:24 15:40:26 15:41:28 15:42:30 15:43:32 15:44:34 15:45:36 Figure 3. Air compressor 1 input power 3.2 Industry B In industry B were applied the same procedures as industry A, data was collected in an air compressor, which function is to air supply the machines responsible for the plastic packs production, and in a centrifugal pump, responsible for the refrigeration of the production line machines. 3.3 Industries C and D The main loads found at these clay manufacturing industries were the set of motor systems named mixer, mill and maromba. Table 4 shows the maromba motor nameplate data that consume a significant parcel of this process. Another system that is also relevant in the process is the mill, which features are shown at table 5.

Table 4. Maromba motor nameplate data industry C Maromba Motor Industry C Manufacturer: WEG Standard Class: N; IP54 Voltage: 380 V Power: 125 cv; Three-phase Frequency: 60 Hz; S.F.: 1,0; Ip/In: 6,6 Current: 182 A Nominal RPM: 1185 Table 5. Mill motor nameplate data industry D Mill Motor D Industry Manufacturer: Motores Bufalo S/A Ind. e Com. Voltage: 380 V (Three-phase) Power: 100 cv Frequency: 60 Hz; S.F.: 1,0 Current: 145 A Nominal RPM: 1175 (6 Poles) 4. Sizing Analysis Some over sized motors were found, as the Exhauster 1 motor in industry A, a 50 cv motor that was operating with 50% of its maximum load. BDMotor software has a motor with similar technical features (motor No. 633) as industry A Exhauster 1 motor. The correct current sizing is displayed at the output window of the software shown in Figure 4. There were no over sized motors in industry B. Figure 5 shows input power values of BDMotor software for the air compressor motor. The industry D mill motor was simulated by BDMotor software considering power sizing mode, with a KOHLBACH No. 422 motor as a model. It was found that this motor is far from its best efficiency. Besides, it has an approximate 18.52 kw shaft mechanical power demand. Figure 6 shows this motor sizes, operating with 25.16% of its maximum loading. Figure 4. WEG nº. 633 standard motor current sizing Figure 5. KOHLBACH nº. 434 standard motor power sizing Figure 6. KOHLBACH nº. 422 standard motor power sizing Based on the similarities between the real motors and the BDMotor software motors was made the sizing analysis using high efficiency and standard motors, in case of over sizing detection, or only high efficiency motors, in cases of correct sized motors. 5. Energetic Efficiency Solutions The industry D mill motor, shown in chart 5 and figure 6, is used as an example to explain the solution procedures of the sizing and/or substitution for a high efficiency motor analysis. The measured input power was 22.97 kw; the simulation was done using the EBERLE No. 1963 high efficiency motor, a 75 cv motor, with 18.52 kw of output power with 20.32 kw of input power (figure 7), this means 11.54% less input power compared to No. 422 motor (reference motor). Loading would reach 33.55%, well sized considering that it would demand up to 70% when turfs of clay are formed.

Figure 7. EBERLE No. 1963 high efficiency motor power sizing In addition to inefficiencies found in some sizing, some shaft-load disarray were also noticed, like the one in Exhauster 1 in industry A, a significant pulley disarray that causes huge electric energy losses, up to 5% for the 10 degrees disarray found. In industry B, based in practical procedures, the electric energy demand can be reduced up to 5.8% after the missing belt installation, eliminating 0.45 kw of mechanical energy demand. Industry C has low power factor as a result of the high reactive power consumption, which implies installation of a 10 kvar capacitor bank. This will reduce about 2% the monthly electric energy bill. Based on previous months industry D records and the information that there is no prevision of load increasing, a revision on the demand contract can reduce an average of 8.9% on monthly electric energy costs. Figure 8 shows the demand idleness in the records of the industry. Figure 9 shows the contract demand optimization curve based on last 13 months profile, reducing the contracted demand in 28 kva. 250 R$ 56.000 R$ 55.300 200 R$ 54.600 Demand (kw) 150 100 50 Total Cost R$ 53.900 R$ 53.200 R$ 52.500 R$ 51.800 R$ 51.100 R$ 50.400 R$ 49.700 0 jan/05 feb/05 mar/05 apr/05 may/05 jun/05 jul/05 aug/05 sep/05 oct/05 nov/05 dec/05 R$ 49.000 180 182 183 185 186 188 189 191 193 194 196 197 199 200 202 204 205 207 208 210 212 Contracted Demand (kw) Figure 8. Industry D demand record Figure 9. Industry D demand optimization Industry A has three electric energy inputs, all of them considered in green schedule and seasonal taxes. A unified measurement opens the possibility of a single demand contract that can reduce electric energy bill 12.5%. The contracted demand taxed is 490 kw, while the optimal demand, based on last 14 months profile, is 440 kw. 6. Results Based on the information collected and technical and economical analysis of the energetic efficiency actions presented, tables 6 to 9 shows investments needed and economy balances for the four analyzed industries.

Table 6. Industry A results Exhauster 1 1.901,15 2.555 402,14 Air compressor 1 1.511,07 1.643 258,52 Exhauster 2 2.662,79 10.140 1.595,80 Air compressor 2 1.877,36 4.348 684,28 Sander (Motor) 1.901,15 1.525 240,01 Coupling 0 4.360 686,16 Measurements Unification 43.000,00 0 10.200,00 Total 52.853,52 24.571 14.066,91 Table 7.Industry B results Air compressor 760,73 1.835 271,67 Coupling and belt 35,00 5.687 842,18 installation Total 795,73 7.522 1.113,85 Table 8. Industry C results Mixer 3.243,00 4.231 757,30 Mill 9.548,21 11.794 2.111,05 Maromba 11.281,56 8.724 1.561,51 Coupling 0 144 25,60 Power Factor correction 480,00 0 3.289,88 Total 24.552,77 24.893 7.745,34 Table 9. Industry D results Mixer 3.243,00 3.972 710,40 Mill 7.925,48 9.924 1.776,00 Maromba 11.281,56 12.096 2.164,68 Coupling 0 156 27,96 Demand Contract 0 0 5.858,28 Adjustment Total 22.450,04 26.148 10.537,32 costs considered is buying motors, maintenance and equipment installation, sometimes done by their own workers, reducing equipment installation costs to zero. 7. Conclusions The Eletrobrás/PROCEL Industrial Electric Efficiency Program proved to be efficient considering Mato Grosso do Sul industries, providing satisfactory economy. Although some industries have no prevision of good payback by replacing over sized or standard motors for high efficiency ones, a tax analysis proved to be a source of financial incomings to develop other actions needed. Furthermore, other solutions, like motor-load coupling maintenance, which proved to be, in some cases, precarious, can reduce costs and improve many investments in energetic efficiency. 8. References ANEEL. Resolução ANEEL No. 074, de 06 de abril de 2005. D.O.U. 07/04/2005. ANEEL. Resolução ANEEL No. 456, de 29 de novembro de 2000. D.O.U. 30/11/2000. EFEI / Eletrobrás, 2001, Conservação de Energia Eficiência Energética de Instalações e Equipamentos. Ed. EFEI. FUPAI, Itajubá-MG. Mamede F., João, 2001, Instalações Elétricas Industriais, 6ª Edição. Editora LTC. Rio de Janeiro. PROCEL / Eletrobrás. Convênio ECV 024/2004 Eletrobrás-UFMS, de novembro de 2004.