COMPRESSORS

www.kaeser.com

For hot air and hot water applications

Heat recovery

Why recover heat?Heat recovery

The question should in fact be: Why not? Amazingly, 100 percent of the (electrical) energy input to a compressor is convert-ed into heat. Up to 96 % of that energy can be reused for heating purposes. This not only reduces primary energy consump-tion, but also significantly improves the total energy balance.

Approx. 5 %heat dissipationfrom the drive

motor

Approx. 76 %heat energy recoverable

throughfl uid cooling

Approx. 2 %heat dissipated

by the compressor into the ambient air

Approx. 2 %heat remaining in the

compressed air

Approx. 15 %

heat energy recoverable

through compressed air

cooling

Approx. 96 %recoverable heat energy

100 %total electrical power

consumption

25 %ambient heat

25 %compressedair energypotential

Heat in the compressorAmazingly, almost 100 percent of the electrical drive energy input to a rotary screw compressor is convert-ed 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 com-pressed 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 how-ever 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

SavingsGas heating € 284 to € 52,381/year

Oil heating € 274 to € 50,570/year

Electrical power

For plate-type heat exchanger systemsCompressor size

“Small” “Medium” “Large”

Compressor model SM 15 BSD 83 FSD 475

Motor rated capacity 9 kW 45 kW 250 kW

Potential savings per year: heating oil842 € 5,422 € 27,313 €

3,826 kg CO2 24,644 kg CO2 124,138 kg CO2

Up to 96 %

reusable heat energy

Heat recovery

3

4

Up to

usable for heating96 %

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 en-ables up to 96 % of the compressor’s total energy require-ment 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.

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.

Heat recovery a winAmazingly, 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 airWarmed 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.

Minimise primary energy consumption for heating

Heat recovery

5

Up to

+70°Chot

Using recyclable heat from the compressor, heat exchang-er 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 cir-cuits and where it is essential that the water being warmed remains uncontaminated, as is the case with cleaning-wa-ter in the food industry for example.

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.

Process, heating and service waterHot water – up to 70 °C – can be produced from reusa-ble compressor heat via PWT heat exchanger systems. Please contact KAESER regarding higher temperature requirements.

Feed heat energy to a heating systemUp 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.

Minimise energy consumption for warming of process, heating and service water

Heat recovery

6

7

Jan Mar Apr May Jun Jul Aug Sep Oct Nov DecFeb

100 %

Required heating energy (%)

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.

Heat is not only needed in winterIt 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 approxi-mately 2000 hours per year.

Equipment

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 exter-nally. Fields of application: Feed into central heating systems, laundries, electro-plating, general process heating, cleaning water in the food industry, swimming pool heating, hot water for shower and washroom facilities

Tube-type heat exchangerDepending on the available water quality, either integrated plate or tube-type heat exchangers can be used in water-cooled systems. Our compressed air spe-cialists can advise you about which design is right for your particular application.

Required heating energy over the course of a year

8

Image: Heat recovery process. Applications for potable water possible only in conjunction with safety heat exchanger (SWT)

Image: Internal layout of a compressor – system comprising plate heat exchanger, thermostatic valve and complete pipework

Shower

Hot water tank

Heat exchanger (Internal)

Air-cooled rotary screw compressor

Hot water heating

Cold water

Hot water

9

Typ bei max. Über-druck

Motor-nenn-

leistung

Maximal verfüg-bare Wärme-

leistung

nutzbare Warmluft-

menge

Kühl-luftauf-heizung

Heizöl-Einsparpotential Erdgas-Einsparpotential

Heizöl CO2 Heizkosten-Einsparung Erdgas CO2 Heizkosten-

Einsparung

bar kW kW MJ/h m³/h K (circa) l kg €/Jahr m³ kg €/Jahr

SX 3SX 4SX 6SX 8

8

2.234

5.5

2.73.44.46.0

10121622

1000100010001300

8101314

456575744

1014

1244156820292765

274345446608

378476616840

756952

12321680

284357462630

SM 9SM 12SM 15

85.57.59

6.89.011.8

253243

2100101317

114915211994

313341485438

689913

1,196

95212611653

190425223306

714946

1,240

SK 22SK 25 8 11

1513.216.5

4859

25003000

1617

22312789

60847606

1,3391.673

18492311

36984622

1,3871,733

ASK 28ASK 34ASK 40

815

18.522

18.422.826.8

668296

400040005000

141716

311038544530

84811051012353

1,8662,3122,718

257731933754

515463867508

1,9332,3952,816

ASD 35ASD 40ASD 50ASD 60

8.5

18.5222530

20.223.828.334.9

7386102126

3800380045005400

16191919

4552536363787865

12413146251739321448

2,7313,2183,8274,719

3772444452856517

75448888

1057013034

2,8293,3333,9644,888

BSD 65BSD 75BSD 83

8.5303745

35.243.452.0

127156187

650080008000

161620

79329780

11718

216312667031955

4,7595,8687,031

657381059711

131461621019422

4,9306,0797,283

CSD 85CSD 105CSD 125

8.5455575

506275

179223270

9400940010700

162021

112231397216902

306053810246092

6,7348,383

10,141

93001157814006

186002315628012

6,9758,684

10,505

CSDX 140CSDX 165 8.5 75

9084101

302364

1100013000

2323

1893022761

5162262069

11,35813,657

1568618861

3137237722

11,76514,146

DSD 145DSD 175DSD 205DSD 240

98.58.58.5

7590110132

8296120145

295346432522

11000130001700020000

22222122

18479216342704332676

50392589967374689107

11,08712,98016,26619,606

15313179272240927077

30626358544481854154

11,48513,44516,80720,308

DSDX 245DSDX 305 8.5 132

160143176

515634 21000 20

253222639662

87880108158

19,33623,797

2670432866

5340865732

20,02824,650

ESD 375ESD 445 8.5 200

250221254

796914

3000034000

2222

4980357240

135813156093

29,88234,344

4127047432

8254094864

30,95335,574

FSD 475FSD 575 8.5 250

315274333

9861199 40000 21

256174775043

168384204642

37,04845,026

5116762185

102234124370

38,37546,639

HSD 662HSD 722HSD 782HSD 842

8.5

360400450500

21232526

74828894

10000

6778

4642511655215904

12659139511505616100

2,7853,0703,3133,542

3847423945754893

7694847891509786

2,8853,1793,4313,670

Note: The highlighted potential energy savings are based on 8 / 8.5 / 9 bar compressors at operational temperature and at max. working pressure. Values may differ for other pressures.

Savings through hot air heat recovery

Calculation example for ASD 35For fuel oil

maximum available heating capacity: 20.2 kW

Fuel value per litre of fuel oil: 9.861 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)

Cost savings:20.2 kW x 2000 h

x € 0.60/l = € 2,731 per year0.9 x 9.861 kWh/l

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: € 0.75/l (1 kW = 1 MJ/h x 3.6)

Cost savings:20.2 kW x 2000 h

x € 0.75/l = € 2,829 per year1.05 x 10.2 kWh/m³

Technical specifications

Type At max. gauge

pressure

Motor rated

capacity

Maximum available heating capacity

Amount of reusable hot air

Amount cooling air is

heated

Potential fuel oil savings Potential natural gas savings

Fuel oil CO2

Heating cost savings Natural gas CO2

Heating cost savings

bar kW kW MJ/h m³/h K (approx.) l kg €/Year m³ kg €/Year

Savi

ngs

pote

ntia

l for

150

0 hr

s

Savi

ngs

pote

ntia

l for

150

0 hr

s

Savi

ngs

pote

ntia

l for

200

0 hr

s

Savi

ngs

pote

ntia

l for

200

0 hr

s

10

Typ bei max. Über-druck

Motor-nenn-

leistung

Maximal verfüg-bare Wärme-

leistung

nutzbare Warmluft-

menge

Kühl-luftauf-heizung

Heizöl-Einsparpotential Erdgas-Einsparpotential

Heizöl CO2 Heizkosten-Einsparung Erdgas CO2 Heizkosten-

Einsparung

bar kW kW MJ/h m³/h K (circa) l kg €/Jahr m³ kg €/Jahr

SX 3SX 4SX 6SX 8

8

2.234

5.5

2.73.44.46.0

10121622

1000100010001300

8101314

456575744

1014

1244156820292765

274345446608

378476616840

756952

12321680

284357462630

SM 9SM 12SM 15

85.57.59

6.89.0

11.8

253243

2100101317

114915211994

313341485438

689913

1,196

95212611653

190425223306

714946

1,240

SK 22SK 25 8 11

1513.216.5

4859

25003000

1617

22312789

60847606

1,3391.673

18492311

36984622

1,3871,733

ASK 28ASK 34ASK 40

815

18.522

18.422.826.8

668296

400040005000

141716

311038544530

84811051012353

1,8662,3122,718

257731933754

515463867508

1,9332,3952,816

ASD 35ASD 40ASD 50ASD 60

8.5

18.5222530

20.223.828.334.9

7386

102126

3800380045005400

16191919

4552536363787865

12413146251739321448

2,7313,2183,8274,719

3772444452856517

75448888

1057013034

2,8293,3333,9644,888

BSD 65BSD 75BSD 83

8.5303745

35.243.452.0

127156187

650080008000

161620

79329780

11718

216312667031955

4,7595,8687,031

657381059711

131461621019422

4,9306,0797,283

CSD 85CSD 105CSD 125

8.5455575

506275

179223270

94009400

10700

162021

112231397216902

306053810246092

6,7348,383

10,141

93001157814006

186002315628012

6,9758,684

10,505

CSDX 140CSDX 165 8.5 75

9084

101302364

1100013000

2323

1893022761

5162262069

11,35813,657

1568618861

3137237722

11,76514,146

DSD 145DSD 175DSD 205DSD 240

98.58.58.5

7590

110132

8296

120145

295346432522

11000130001700020000

22222122

18479216342704332676

50392589967374689107

11,08712,98016,26619,606

15313179272240927077

30626358544481854154

11,48513,44516,80720,308

DSDX 245DSDX 305 8.5 132

160143176

515634 21000 20

253222639662

87880108158

19,33623,797

2670432866

5340865732

20,02824,650

ESD 375ESD 445 8.5 200

250221254

796914

3000034000

2222

4980357240

135813156093

29,88234,344

4127047432

8254094864

30,95335,574

FSD 475FSD 575 8.5 250

315274333

9861199 40000 21

256174775043

168384204642

37,04845,026

5116762185

102234124370

38,37546,639

HSD 662HSD 722HSD 782HSD 842

8.5

360400450500

21232526

74828894

10000

6778

4642511655215904

12659139511505616100

2,7853,0703,3133,542

3847423945754893

7694847891509786

2,8853,1793,4313,670

Typ bei max. Über-druck

Motor-nenn-

leistung

Maximal verfüg-bare Wärme-

leistung

WarmwassermengeAufheizung auf 70 °C

Platzierung des PTG-Systems

Heizöl-Einsparpotential Erdgas-Einsparpotential

Heizöl CO2Heizkosten-Einsparung Erdgas CO2

Heizkosten-Einsparung

bar kW kW MJ/h (ΔT 25 K) m³/h (ΔT 55 K) m³/h int./ext. l kg €/Jahr m³ kg €/Jahr

SM 9SM 12SM 15

85.57.59

4.66.28.3

172230

0.160.210.29

0.070.100.13

External777

10481403

211928583826

466629842

644868

1162

128817362324

483651872

SK 22SK 25 8 11

159.412.0

3443

0.320.41

0.150.19 External 1589

202843335530

9531,217

13171681

26343362

9881,261

ASK 28ASK 34ASK 40

815

18.522

13.616.919.8

496171

0.470.580.68

0.210.260.31

Internal229928563347

626977889127

1,3791,7142,008

190523672773

381047345546

1,4291,7752,080

ASD 35 ASD 40 ASD 50 ASD 60

8.5

18.5 22 25 30

15.2 18.1 21.6 26.6

55 65 78 96

0.52 0.62 0.74 0.92

0.24 0.28 0.34 0.42

Internal

3425 4079 4868 5994

9340 11123 13275 16346

2,055 2,447 2,921 3,596

2838 3380 4034 4967

5676 6760 8068 9934

2,129 2,535 3,026 3,725

BSD 65 BSD 75 BSD 83

8.530 37 45

27.1 33.5 40.1

98 121 144

0.93 1.15 1.38

0.42 0.52 0.63

Internal6107 7549 9037

16654 20586 24644

3,664 4,529 5,422

5061 6256 7488

10122 12512 14976

3,796 4,692 5,616

CSD 85 CSD 105 CSD 125

8.545 55 75

38.6 48.4 59.0

139 174 212

1.33 1.67 2.03

0.60 0.76 0.92

Internal8699

10907 13296

23722 29743 36258

5,219 6,5447,978

7208 9038

11018

14416 18076 22036

5,406 6,779 8,264

CSDX 140 CSDX 165 8.5 75

9066 80

238 288

2.30 2.80

1.03 1.25 Internal 14873

1802840559 49162

8,924 10,817

12325 14939

24650 29878

9,244 11,204

DSD 145DSD 175DSD 205DSD 240

98.58.58.5

75 90 110 132

61 7188 107

220 256 317 385

2.102.40 3.003.70

0.961.111.381.68

Internal

1374716000 1983124113

37488 43632 5407965756

8,248 9,600

11,899 14,468

11391 132591643319981

22782 26518 32866 39962

8,543 9,944

12,325 14,986

DSDX 245 DSDX 305 8.5 132

160105130

378468

3.604.50

1.642.04 Internal 23662

292966452679890

14,19717,578

1960824276

3921648552

14,70618,207

ESD 375 ESD 445 8.5 200

250162187

583673

5.66.4

2.542.93 Internal 36507

4214199555

11491921,90425,285

3025234921

6050469842

22,689 26,191

FSD 475 FSD 575 8.5 250

315202246

727886

7.08.5

3.163.85 Internal 45522

55437124138151177

27,313 33,262

3772245938

7544491876

28,292 34,454

HSD 662 HSD 722 HSD 782 HSD 842

8.5

360400450500

291323348374

1048116312531346

10.011.112.012.9

4.565.065.455.86

Internal

65578727907842384283

178831 198498 213860 229840

39,34743,67447,05450,570

54342603176498669841

108684 120634 129972 139682

40,75745,23848,74052,381

Note: The highlighted potential energy savings are based on 8 / 8.5 / 9 bar compressors at operational temperature and at max. working pressure. Values may differ for other pressures.

Savings with PTG plate heat exchanger system

Calculation example for ASD 35For fuel oil

maximum available heating capacity: 15.2 kW

Fuel value per litre of fuel oil: 9.861 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)

Cost savings:15.2 kW x 2000 h

x € 0.60/l = € 2,055 per year0.9 x 9.861 kWh/l

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: € 0.75/l (1 kW = 1 MJ/h x 3.6)

Cost savings:15.2 kW x 2000 h

x € 0.75/l = € 2,129 per year1.05 x 10.2 kWh/m³

Type At max. gauge

pressure

Motor rated

capacity

Maximum available heating capacity

Heated water volumeHeated to 70 °C

Installation of the PTG

system

Potential fuel oil savings Potential natural gas savings

Fuel oil CO2Heating cost

savings Natural gas CO2Heating cost

savings

bar kW kW MJ/h (ΔT 25 K) m³/h (ΔT 55 K) m³/h Int./ext. l kg €/Year m³ kg €/Year

Savi

ngs

pote

ntia

l for

150

0 hr

s

Savi

ngs

pote

ntia

l for

150

0 hr

s

Savi

ngs

pote

ntia

l for

200

0 hr

s

Savi

ngs

pote

ntia

l for

200

0 hr

s

11

The world is our homeAs 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 SEP.O. Box 2143 – 96410 Coburg – GERMANY – Tel +49 9561 640-0 – Fax +49 9561 640-130e-mail: productinfo@kaeser.com – www.kaeser.com P-

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18