heat recovery for hot air and hot water applications · 2020. 1. 19. · 6 heat recovery ptg plate...

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Heat recovery forhot air and hot waterapplications

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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 airApprox. 15 % heat energy recov-

erable throughcompressed air

cooling

Approx. 96 %recoverable heat energy

Up to 100 %total electrical power

consumption

Up to 25 %ambient heat

Up to 25 %compressed air energy potential

Heat in the compressor

Amazingly, almost 100 percent of the electrical drive energy input to a rotary screw compressor is convert-ed into heat.

The adjacent heat fl ow 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 approximately25 percent of the compressor's electricalpower 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.

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 this energy can be recovered and reused for space heating or hot water production purposes. This not only reduces primary energy consumption, but also signifi cantly improves the total energy balance.

Saves money and benefi ts the environment

For plate heatexchanger systems

Compressor size

“Small” “Medium” “Large”

Compressor model SM 15 BSD 83 FSD 471

Rated power 9 kW 45 kW 250 kW

Annual savingspotential withfuel oil

€ 982 € 6,326 € 33,916

3,826kg CO2

24,644kg CO2

132,126kg CO2

Gas heating294 up to 55,742 €/year

Heatrecovery

Up to 96%

reusableheat energy

Heat recovery

Electrical power consumption

Oil heating331 up to 62,784 €/year

► See pages 10 and 11 for details regarding calculation of savings potential.

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Heat recoveryMinimise primary energyconsumption for heating

Heat neighbouring rooms

When using recyclable heat for space heating, duct-ing simply feeds the warmed cooling air to where it is needed, e.g. in adjacent facilities, such as warehous-es or workshops.

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.

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 percent of the compressor's total energy requirement to be recov-ered and used for heating purposes. This is the case irrespective of whether fl uid-injection cooled com-pressors or dry-running screw compressors are used.

Heat recovery a win

Amazingly, 100 percent of the electrical drive 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!

Up to

energy reusable for heating purposes

blbl96%

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6

Heat recovery

PTG plate heat exchanger

High quality plate type heat exchangers are the fi rst 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 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 signifi cantly reduces primary energy demand required for heating purposes.

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

+70°Chot

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.

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Jan Mar Apr May Jun Jul Aug Sep Oct Nov DecFeb

100 %

Equipment

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 signifi cant 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.

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 regarding which design is right for your particular application.

Hot air heatrecovery

All KAESER rotary screw compressorscan be fi tted with exhaust ducting. The ducting is installed on-site. Neigh-bouring rooms and warehouse space, for example, can be heated with the warmed cooling air.

Fields of 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 compres-sor 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

Requiredheating

energy (%)

Required heating energy over the course of a year

Image: PTG plate heat exchanger Image: Tube-type heat exchanger

Image: Heat recovery process

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

Shower

Hot water tank

Heat exchanger(Internal)

Air-cooledrotary screw compressor

Hot water heating

Cold waterHot water

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bei Schrauben-kompressor

bei max. Über-druck

Motor-nenn-

leistung

Maximal verfüg-bare Wärme-

leistung

nutzbare Warmluft-

menge

Kühl-luftauf-heizung

Heizöl-Einsparpotential Erdgas-Einsparpotential

Heizöl

l

CO2

kg

Heizkosten-Einsparung

€/Jahr

Erdgas

m³

CO2

kg


€/JahrTyp bar kW kW MJ/h m³/h K (circa)

SX 3SX 4SX 6SX 8

8

2.234

5.5

2.83.54.56.1

10131622

1000100010001300

8111414

4735927611031

1290161420752812

331414533722

392490630854

78498012601708

294368473641

SM 9SM 12SM 15

85.57.59

6.89.011.8

253243

2100101317

114915211994

313341485438

8041,0651,396

95212611653

190425223306

714946

1,240

SK 22SK 25 8 11

1513.216.5

4859

25003000

1617

22312789

60847606

1,5621,952

18492311

36984622

1,3871,733

ASK 28ASK 34ASK 40

815

18.522

18.422.826.8

667896

400040005000

141716

311038544530

84811051012353

2,1772,6983,171

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

3,1863,7544,4655,506

3772444452856517

75448888

1057013034

2,8293,3333,9644,888

BSD 65BSD 75BSD 83

8.5303745

35.243.452.0

127156187

650080008000

161620

7932978011718

216312667031955

5,5526,8468,203

657381059711

131461621019422

4,9306,0797,283

CSD 85CSD 105CSD 125

8.5455575

506376

180227274

9400940010700

162021

112681419717127

307283871546705

7,8889,938

11,989

93371176514192

186742353028384

7,0038,824

10,644

CSDX 140CSDX 165 8.5 75

9085

102306367

1100013000

2324

1915522986

5223662683

13,40916,090

1587319048

3174638096

11,90514,286

DSD 142DSD 172DSD 202DSD 238

98.58.58.5

7590110132

8498

124150

302353446540

9000140001400021000

28212721

18930220852794433803

51622602267620392181

13,25115,46019,56123,662

15686183012315628011

31372366024631256022

11,76513,72617,36721,008

DSDX 245DSDX 305 8.5 132

160143176

515634 21000 20

253222639662

87880108158

22,55827,763

2670432866

5340865732

20,02824,650

ESD 352ESD 442 8.5 200

250221254

796914 34000 20

224980357240

135813156093

34,86240,068

4127047432

8254094864

30,95335,574

FSD 471FSD 571 8 250

315278341

10011228 40000 21

266264976846

170844209559

43,85453,792

5191463679

103828127358

38,93647,759

HSD 662HSD 722HSD 782HSD 842

8.5

360400450500

21232526

74828894

10000

6778

4642511655215904

12659139511505616100

3,2493,5813,8654,133

3847423945754893

7694847891509786

2,8853,1793,4313,670



Motor-nenn-

leistung

Maximal verfügbare

Wärmeleistung

WarmwassermengeAufheizung auf 70 °C

Platzierung des PTG-Systems


Heizöl

l

CO2

Einsparungkg


€/Jahr

Erdgas

m³

CO2

Einsparungkg


€/JahrTyp bar kW kW MJ/h(ΔT 25 K)

m³/h(ΔT 55 K)

m³/h int./ext.

SM 9SM 12SM 15

85.57.59

4.66.28.3

172230

0.160.210.29

0.070.100.13

External777

10481403

211928583826

544734982

644868

1162

128817362324

483651872

SK 22SK 25 8 11

159.4

12.03443

0.320.41

0.150.19 External 1589

202843335530

1,1121,420

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

1,6091,9992,343

190523672773

381047345546

1,4291,7752,080



Motor-nenn-

leistung

Maximalverfügbare

Wärmeleistung

Warmwassermenge Aufheizung auf 70 °C

Platzierung des PTG-Systems


Heizöl

l

CO2

kg


€/Jahr

Erdgas

m³

CO2

kg


€/JahrTyp bar kW kW MJ/h (ΔT 25 K) m³/h

(ΔT 55 K) m³/h int./ext.

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

2,398 2,855 3,408 4,196

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

4,275 5,284 6,326

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

6,0897,6359,307

7208 9038

11018

14416 18076 22036

5,406 6,779 8,264

CSDX 140 CSDX 165 8.5 75

9066 79

238 284

2.30 2.70

1.03 1.24 Internal 14873

1780340559 48549

10,411 12,462

12325 14753

24650 29506

9,244 11,065

DSD 142 DSD 172 DSD 202 DSD 238

98.58.58.5

75 90

110 132

66 76 97

118

238 274 349 425

2.30 2.60 3.30 4.10

1.03 1.19 1.52 1.85

Internal

14873 17127 21859 26592

40559 46705 59609 72516

10,411 11,989 15,301 18,614

12325 14192 18114 22035

24650 28384 36228 44070

9,244 10,64413,586 16,526

DSDX 245 DSDX 305 8.5 132

160105130

378468

3.604.50

1.642.04 Internal 23662

292966452679890

16,56320,507

1960824276

3921648552

14,70618,207

ESD 352 ESD 442 8.5 200

250172 198

619 713

5.90 6.80

2.69 3.10 Internal 38761

44620105701 121679

27,133 31,234

32120 36975

64240 73950

24,090 27,731

FSD 471 FSD 571 8 250

315215 266

774 958

7.40 9.20

3.37 4.17 External 48451

59944132126 163467

33,916 41,961

40149 49673

80298 99346

30,112 37,255

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

45,90550,95354,89658,998

54342603176498669841

108684 120634 129972 139682

40,75745,23848,74052,381

Forrotary screwcompressor

At max.operatingpressure

Ratedmotorpower

Maximumavailable

heat capacity

Heated water volumeHeated to 70 °C

Installationof the PTG

system

Potential fuel oil saving Potential natural gas saving

Fuel oil

l

CO2

savingkg

Heating costsaving€/Year

Natural gasm³

CO2

savingkg

Heating costsaving€/YearModel bar kW kW MJ/h

(ΔT 25 K)m³/h

(ΔT 55 K) m³/h Int./ext.

SM 9SM 12SM 15

SK 22SK 25

ASK 28ASK 34ASK 40

Savings with PTG plate heat exchanger system

Forrotary screwcompressor

At max. operating pressure

Ratedmotorpower

Maximumavailable

heat capacity

Heated water volumeHeated to 70 °C

Installationof the PTG

system


Fuel oil

l

CO2

kg


Natural gasm³

CO2

kg

Heating costsaving€/YearModel bar kW kW MJ/h

(ΔT 25 K)m³/h

(ΔT 55 K) m³/h Int./ext.


BSD 65BSD 75BSD 83


CSDX 140CSDX 165


DSDX 245DSDX 305

ESD 352ESD 442

FSD 471FSD 571

HSD 662HSD 722HSD 782HSD 842

Savings with PTG heat exchanger systems

Technical specifi cations

For rotary screw compressor

At max.operatingpressure

Ratedmotorpower

Maximum availableheatingcapacity

Usablevolume ofheating air

Amountcooling air is

heated


Fuel oil

l

CO2

kg


Natural gas

m³

CO2

kg

Heating costsaving€/YearModel bar kW kW MJ/h m³/h K (approx.)

SX 3SX 4SX 6SX 8

SM 9SM 12SM 15

SK 22SK 25

ASK 28ASK 34ASK 40


BSD 65BSD 75BSD 83


CSDX 140CSDX 165


DSDX 245 DSDX 305

ESD 352ESD 442

FSD 471FSD 571

HSD 662 HSD 722 HSD 782 HSD 842

Savings through hot air heat recovery

Calculation example for ASD 35

For fuel oil

Maximum available heat capacity: 15.2 kWFuel value per litre of fuel oil: 9.861 kWh/lFuel oil heating effi ciency: 0.9Price per litre of fuel oil: 0.70 €/l 1 kW = 1 MJ/h x 3.6

Cost saving: x 0.70 €/l = € 2,398 per year15.2 kW x 2000 h0.9 x 9.861 kWh/l

For natural gas

Maximum available heat capacity: 15.2 kWFuel value per m³ natural gas: 10.2 kWh/m³Natural gas heating effi ciency: 1.05Price per m³ of natural gas: 0.75 €/m³ 1 kW = 1 MJ/h x 3.6

Cost saving: x 0.75 €/m³ = € 2,129 per year15.2 kW x 2000 h1.05 x 10.2 kWh/m³

Calculation example for ASD 35

For fuel oil

Maximum available heat capacity: 20.2 kWFuel value per litre of fuel oil: 9.861 kWh/lFuel oil heating effi ciency: 0.9Price per litre of fuel oil: 0.70 €/l 1 kW = 1 MJ/h x 3.6

Cost saving: x 0.70 €/l = € 3,186 per year20.2 kW x 2000 h0.9 x 9.861 kWh/l

For natural gas

Maximum available heat capacity: 20.2 kWFuel value per m³ natural gas: 10.2 kWh/m³Natural gas heating effi ciency: 1.05Price per m³ of natural gas: 0.75 €/m³ 1 kW = 1 MJ/h x 3.6

Cost saving: x 0.75 €/m³ = € 2,829 per year20.2 kW x 2000 h1.05 x 10.2 kWh/m³

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 diff er for other pressures.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 diff er for other pressures.

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KAESER – The world is our home

KAESER KOMPRESSOREN SEP.O. Box 2143 – 96410 Coburg – GERMANY – Tel +49 9561 640-0 – Fax +49 9561 640-130e-mail: [email protected] – www.kaeser.com

As one of the world’s largest compressed air systems providers and compressor manufacturers, KAESER KOMPRESSOREN is represented throughout the world by a comprehensive network of branches, subsidiary companies and authorised partners in over 100 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 all products operate at the peak of their performance at all times and provide maximum availability.

www.kaeser.com

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heat recovery for hot air and hot water applications · 2020. 1. 19. · 6 heat recovery ptg plate...

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