COMPRESSORS Heat recovery For hot air and hot water applications www.kaeser.com
Heat recovery Why recover heat? The question should in fact be: Why not? Amazingly, 100 percent of the (electrical) energy input to a compressor is converted into heat. Up to 96 % of that energy can be reused for heating purposes. This not only reduces primary energy consumption, but also significantly improves the total energy balance. Approx. 5 % heat dissipation from the drive motor Approx. 76 % heat energy recoverable through fl uid cooling Approx. 96 % recoverable heat energy 100 % total electrical power consumption Approx. 15 % heat energy recoverable through compressed air cooling 25 % ambient heat 25 % compressed air energy potential Approx. 2 % heat dissipated by the compressor into the ambient air Approx. 2 % heat remaining in the compressed air Heat in the compressor Amazingly, almost 100 percent of the electrical drive energy input to a rotary screw compressor is converted into heat. The adjacent heat flow diagram (left) shows how this energy is distributed throughout the compressor system and how it can be recovered: Approximately 96 percent of the energy can be recovered for reuse, two percent remains in the compressed air and two percent radiates away from the compressor package into the ambient surroundings. So where does the usable energy in compressed air come from? The answer is actually quite simple and perhaps surprising: during the compression process and conversion of the electrical drive energy into heat, the compressor charges the air it draws in with energy potential. This corresponds to approximately 25 percent of the compressor's electrical power consumption. This energy is only usable however once the compressed air expands at its point of use and in so doing absorbs heat energy from the ambient surroundings. Of course the amount of this energy that is available for use depends on the pressure and leakage losses within the compressed air system. See pages 10 and 11 for details regarding calculation of savings potential. 2
Saves money and benefits the environment Savings Gas heating 24 to 52,31/year Oil heating 274 to 50,570/year Heat recovery Up to 96 % reusable heat energy Electrical power For plate-type heat exchanger systems Compressor size Small Medium Large Compressor model SM 15 BSD 3 FSD 4 Motor rated capacity 9 kw 45 kw 250 kw Potential savings per year: heating oil 42 5,4 27,313 3,26 kg CO 2 24,644 kg CO 2 124,13 kg CO 2 3
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Heat recovery Minimise primary energy consumption for heating The enclosed, compact design of modern rotary screw compressors makes them especially suitable for heat recovery. Direct use of the recyclable heat via a ducting system enables up to 96 % of the compressor s total energy requirement to be recovered and used for heating purposes. This is the case irrespective of whether fluid-injection cooled compressors or dry-running screw compressors are used. Up to 96 % usable for heating Heat recovery a win Amazingly, 100 percent of the electrical energy input to a compressor is converted into heat. From that, up to 96 percent is available for heat recovery purposes. Use this potential to your advantage! Heating with hot air Warmed compressor cooling air can be ducted away to provide highly effective space heating. With this method, up to 96 percent of the compressor s input energy can therefore be recovered as heat either for space heating or for use as process heat. Heat adjacent rooms When using recyclable heat for space heating, ducting simply feeds the warmed cooling air to where it is needed, e.g. adjacent facilities, such as warehouses or workshops. 5
Heat recovery Minimise energy consumption for warming of process, heating and service water Using recyclable heat from the compressor, heat exchanger systems can provide on-demand heating and service water warmed to temperatures up to 70 C, or even 90 C, depending on requirement. Conventional warming of heating and service water using recyclable heat is performed by PTG plate heat exchanger systems. Special fail-safe heat exchangers are recommended for applications that have no other interconnecting water circuits and where it is essential that the water being warmed remains uncontaminated, as is the case with cleaning-water in the food industry for example. Up to +70 C hot Process, heating and service water Hot water up to 70 C can be produced from reusable compressor heat via PWT heat exchanger systems. Please contact KAESER regarding higher temperature requirements. Feed heat energy to a heating system Up to 76 percent of the original input energy for the compressor system can be recovered for use in hot water heating systems and service water installations. This significantly reduces primary energy demand required for heating purposes. PTG plate heat exchanger High quality plate-type heat exchangers are the first choice when it comes to using recyclable heat from rotary screw compressors for warming process and service water, or for process heat production. 6
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Equipment Hot air heat recovery All KAESER-rotary screw compressors can be fitted with exhaust ducting. The ducting is installed on-site. Adjacent rooms and warehouse space, for example, can be heated with the warmed cooling air. Application: Drying processes, heating of halls and buildings, air curtain systems, pre-heating of burner air. PTG plate heat exchanger system Rotary screw compressors from the SM series (from 5.5 kw) upwards can be equipped with PTG systems. Depending on the size of the compressor system, the PTG heat exchanger is either integrated within the unit or is installed externally. Fields of application: Feed into central heating systems, laundries, electroplating, general process heating, cleaning water in the food industry, swimming pool heating, hot water for shower and washroom facilities Tube-type heat exchanger Depending on the available water quality, either integrated plate or tube-type heat exchangers can be used in water-cooled systems. Our compressed air specialists can advise you about which design is right for your particular application. Required heating energy over the course of a year Required heating energy (%) 100 % Heat is not only needed in winter It goes without saying that heating is necessary during the winter months, but it is also required for significant periods at other times of the year, such as in spring and autumn. This means that heating energy is actually required for approximately 2000 hours per year. Feb Jan Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Heat exchanger () Air-cooled rotary screw compressor Hot water Cold water Hot water tank Hot water heating Shower Image: Heat recovery process. Applications for potable water possible only in conjunction with safety heat exchanger (SWT) Image: layout of a compressor system comprising plate heat exchanger, thermostatic valve and complete pipework 9
Technical specifications Savings through hot air heat recovery Type SX 3 SX 4 SX 6 SX SM 9 SM 12 SM 15 SK SK 25 ASK 2 ASK 34 ASK 40 bei At max. gauge Überdruck pressure Motornennleistung rated capacity Maximum Maximal available verfügbare heating Wärmeleistung capacity Amount nutzbare of Warmluftmenge hot reusable air Amount Kühl- cooling luftauf- heizung air is heated Potential Heizöl-Einsparpotential fuel oil savings Potential Erdgas-Einsparpotential natural savings Heating Heizkosten- cost Fuel Heizöl oil CO2 2 Einsparung savings Heating Heizkosten- cost Natural Erdgas gas CO2 2 Einsparung savings bar kw kw MJ/h m³/h K K (approx.) (circa) l kg /Year /Jahr m³ kg /Year /Jahr 2.2 3 4 5.5 5.5 7.5 9 11 15 15 1 2.7 3.4 4.4 6.0 6. 9.0 11. 13.2.5 1.4. 26. 10 12 25 32 43 4 59 66 2 96 1000 1000 1000 1300 2100 2500 3000 4000 4000 5000 10 13 14 10 13 17 17 14 17 456 5 744 1014 1149 1521 1994 31 279 3110 354 4530 1244 156 2029 2765 3133 414 543 604 7606 41 10510 12353 Savings potential for 1500 hrs 274 345 446 60 69 913 1,196 1,339 1.673 1,66 2,312 2,71 37 476 6 40 952 1261 53 149 2311 2577 3193 34 6 952 1232 0 1904 25 3306 369 46 5154 636 0 Savings potential for 1500 hrs 24 357 462 630 714 946 1,240 1,37 1,733 1,933 2,395 2, ASD 35 ASD 40 ASD 50 ASD 60 1 25 30 20.2 23. 2.3 34.9 73 6 102 126 300 300 4500 5400 19 19 19 4552 5363 637 765 12413 14625 17393 2144 2,731 3,21 3,27 4,719 3772 4444 525 6517 44 10570 13034 2,29 3,333 3,964 4, BSD 65 BSD BSD 3 30 37 45 35.2 43.4 52.0 127 156 17 6500 000 000 20 7932 970 1171 231 26670 31955 4,9 5,6 7,031 6573 105 9711 13146 210 194 4,930 6,079 7,23 CSD 5 CSD 105 CSD 125 CSDX 140 CSDX 5 DSD 145 DSD 1 DSD 205 DSD 240 DSDX 245 DSDX 305 9 45 55 90 90 110 132 132 0 50 62 4 101 2 96 120 145 143 176 179 3 270 302 364 295 346 432 5 515 634 9400 9400 10700 11000 13000 11000 13000 17000 20000 21000 20 21 23 23 21 20 25 113 13972 902 1930 761 1479 234 27043 32676 326 39662 30605 3102 46092 5 62069 50392 5996 73746 9107 70 1015 Savings potential for 2000 hrs 6,734,33 10,141 11,35 13,657 11,07 12,90,266 19,606 19,336 23,797 9300 1157 14006 1566 1 15313 17927 409 27077 26704 3266 00 23156 2012 31372 377 30626 3554 441 54154 5340 65732 Savings potential for 2000 hrs 6,9,64 10,505 11,765 14,146 11,45 13,445,07 20,30 20,02 24,650 ESD 3 ESD 445 200 250 1 254 796 914 30000 34000 4903 57240 13513 156093 29,2 34,344 41270 47432 2540 9464 30,953 35,574 FSD 4 FSD 5 250 315 274 333 96 1199 40000 21 25 61747 043 34 204642 37,04 45,026 517 6215 1034 124370 3,3 46,639 HSD 662 HSD 7 HSD 72 HSD 42 360 400 450 500 21 23 25 26 74 2 94 10000 6 7 7 4642 51 5521 5904 12659 13951 15056 100 2, 3,070 3,313 3,542 347 4239 45 493 7694 47 9150 976 2,5 3,179 3,431 3,670 Calculation example for ASD 35 For fuel oil maximum available heating capacity: 20.2 kw Fuel value per litre of fuel oil: 9.61 kwh/l Fuel oil heating efficiency: 0.9 Price per litre of fuel oil: 0.60/l (1 kw = 1 MJ/h x 3.6) For natural gas maximum available heating capacity: 20.2 kw Fuel value per m³ natural gas: 10.2 kwh/m³ Natural gas heating efficiency: 1.05 Price per m³ of natural gas: 0./l (1 kw = 1 MJ/h x 3.6) Cost savings: 20.2 kw x 2000 h 0.9 x 9.61 kwh/l x 0.60/l = 2,731 per year Cost savings: 20.2 kw x 2000 h 1.05 x 10.2 kwh/m³ x 0./l = 2,29 per year Note: The highlighted potential energy savings are based on / / 9 bar compressors at operational temperature and at max. working pressure. Values may differ for other pressures. 10
Savings with PTG plate heat exchanger system Type SM 9 SM 12 SM 15 SK SK 25 ASK 2 ASK 34 ASK 40 bei At max. gauge Überdruck pressure Motornennleistung rated capacity Maximum Maximal available verfügbare heating Wärmeleistung capacity Heated Warmwassermenge water volume Aufheizung Heated to auf 70 70 C C Platzierung Installation of des the PTG- Systems system Potential Heizöl-Einsparpotential fuel oil savings Heating Heizkosten- cost Fuel Heizöl oil CO 2 Einsparung savings Potential Erdgas-Einsparpotential natural savings Heating Heizkosten- cost Natural Erdgas gas CO 2 Einsparung savings bar kw kw MJ/h (ΔT 25 K) m³/h (ΔT 55 K) m³/h Int./ext. int./ext. l kg /Year /Jahr m³ kg /Year /Jahr 5.5 7.5 9 11 15 15 1 4.6 6.2.3 9.4 12.0 13.6.9 19. 17 30 34 43 49 61 71 0. 0.21 0.29 0.32 0.41 0.47 0.5 0.6 0.07 0.10 0.13 0.15 0.19 0.21 0.26 0.31 External External 777 104 1403 159 202 99 256 3347 2119 25 326 4333 5530 6269 77 9127 Savings potential for 1500 hrs 466 629 42 953 1,217 1,379 1,714 2,00 644 6 12 1317 1 1905 2367 2773 12 1736 2324 2634 3362 310 4734 5546 Savings potential for 1500 hrs 43 651 72 9 1,261 1,429 1,7 2,00 ASD 35 ASD 40 ASD 50 ASD 60 1 25 30 15.2 1.1 21.6 26.6 55 65 7 96 0.52 0.62 0.74 0.92 0.24 0.2 0.34 0.42 3425 4079 46 5994 9340 11123 132 346 2,055 2,447 2,921 3,596 23 330 4034 4967 5676 6760 06 9934 2,129 2,535 3,026 3,725 BSD 65 BSD BSD 3 30 37 45 27.1 33.5 40.1 9 121 144 0.93 1.15 1.3 0.42 0.52 0.63 6107 49 9037 654 2056 24644 3,664 4,529 5,4 5061 6256 74 101 12512 14976 3,796 4,692 5,6 CSD 5 CSD 105 CSD 125 45 55 3.6 4.4 59.0 139 174 212 1.33 1.67 2.03 0.60 0.76 0.92 699 10907 13296 237 29743 3625 5,219 6,544 7,97 720 903 1101 144 1076 036 5,406 6,779,264 CSDX 140 CSDX 5 DSD 145 DSD 1 DSD 205 DSD 240 DSDX 245 DSDX 305 9 90 90 110 132 132 0 66 0 61 71 107 105 130 23 2 0 256 317 35 37 46 2.30 2.0 2.10 2.40 3.00 3.70 3.60 4.50 1.03 1.25 0.96 1.11 1.3 1.6 1.64 2.04 1473 102 13747 000 1931 24113 23662 29296 40559 492 374 43632 54079 656 64526 7990 Savings potential for 2000 hrs,924 10,17,24 9,600 11,99 14,46 14,197 17,57 12325 14939 11391 13259 433 1991 1960 24276 24650 297 72 2651 3266 39962 392 4552 Savings potential for 2000 hrs 9,244 11,204,543 9,944 12,325 14,96 14,706 1,207 ESD 3 ESD 445 200 250 2 17 53 673 5.6 6.4 2.54 2.93 36507 42141 99555 114919 21,904 25,25 30252 34921 60504 6942,69 26,191 FSD 4 FSD 5 250 315 202 246 727 6 7.0 3. 3.5 455 55437 12413 151177 27,313 33,262 377 4593 444 9176 2,292 34,454 HSD 662 HSD 7 HSD 72 HSD 42 360 400 450 500 291 323 34 374 104 13 1253 1346 10.0 11.1 12.0 12.9 4.56 5.06 5.45 5.6 6557 72790 7423 423 1731 1949 21360 940 39,347 43,674 47,054 50,570 54342 60317 6496 6941 1064 120634 129972 13962 40,7 45,23 4,740 52,31 Calculation example for ASD 35 For fuel oil maximum available heating capacity: 15.2 kw Fuel value per litre of fuel oil: 9.61 kwh/l Fuel oil heating efficiency: 0.9 Price per litre of fuel oil: 0.60/l (1 kw = 1 MJ/h x 3.6) For natural gas maximum available heating capacity: 15.2 kw Fuel value per m³ natural gas: 10.2 kwh/m³ Natural gas heating efficiency: 1.05 Price per m³ of natural gas: 0./l (1 kw = 1 MJ/h x 3.6) Cost savings: 15.2 kw x 2000 h 0.9 x 9.61 kwh/l x 0.60/l = 2,055 per year Cost savings: 15.2 kw x 2000 h 1.05 x 10.2 kwh/m³ x 0./l = 2,129 per year Note: The highlighted potential energy savings are based on / / 9 bar compressors at operational temperature and at max. working pressure. Values may differ for other pressures. 11
The world is our home As one of the world s largest compressed air system providers and compressor manufacturers, KAESER KOMPRESSOREN is represented throughout the world by a comprehensive network of branches, subsidiary companies and authorised partners in over 140 countries. With innovative products and services, KAESER KOMPRESSOREN s experienced consultants and engineers help customers to enhance their competitive edge by working in close partnership to develop progressive system concepts that continuously push the boundaries of performance and compressed air effi ciency. Moreover, the decades of knowledge and expertise from this industry-leading system provider are made available to each and every customer via the KAESER group s global computer network. These advantages, coupled with KAESER s worldwide service organisation, ensure that every product operates at the peak of its performance at all times and provides maximum availability. KAESER KOMPRESSOREN SE P.O. Box 2143 96410 Coburg GERMANY Tel +49 9561 640-0 Fax +49 9561 640-130 e-mail: productinfo@kaeser.com www.kaeser.com P-645ED Subject to alteration without notice!.20/1