Latest Developments in Compressors & Refrigeration Systems ... · Bock GLC 2010 –14.04.2010...

Bock GLC 2010 – 14.04.2010 Slide 1© Bock Kältemaschinen GmbH, 2009

Latest Developments

in Compressors &

Refrigeration Systems

using R744 (CO2)


Overview

• Refrigeration systems with CO2

• Mobile applications

• Heat pump applications

• Development in supermarket applications

• Economizer systems

• Radial piston compressors for CO2 applications

• Air cooled compressors in CO2 systems

• Comparison air-cooled and suction gas-cooled CO2 compressors

• Conclusion and outlook


Applications of Bock CO2 Compressors

• Small heat pumps

• Large industrial heat pumps

• Industrial cooling

• Supermarket

• Convenience stores

• Transport cooling

• (Automobile), bus und railway (air conditioning)

• Building service (air conditioning)


+ Simple system with less components

+ Oil management

+ Control system just with one valve

- Susceptible to leakage

- Standstill pressure

- No high pressure control (Qo or COP)

- Over heating and hot gas temperature

Mobile Air Conditioning for Bus Application

2

1

3

4

5 6

Evaporator

Gas cooler

Compressor

Oil separator

ExV 1

IHX

5

4 3 2

16

Dru

ck in

bar

Enthalpie in kJ/kg

∆h

∆h

R744

Enthalpy in kJ/kg

Pre

ssur

e in

bar


Mobile Air Conditioning

Bus application (A/C) with open transcritical CO2 compressor

Application by company Konvekta


Mobile Air Conditioning

Application by company Konvekta

Railway application (A/C) with transcritical semi-hermetic radial piston compressor


Heat Pumps

• Heat pump with combination of water heating and air heating (study)

• Split heat exchanger for heat glide adjustment

• Internal heat exchanger increased compressor discharge temperature

• High pressure control for adapted application conditions

2

1

3

4

5

6 7

A B

Entropie in kJ/(kg K)

Tem

pera

tur

in °C

1

2

3

4

67

R744

Gas cooler A

Gas cooler B

C

Air Heating

Evaporator(Heat source)

Gas cooler

Compressor

Oil separator

Expansion valve for high pressure control

Accumulator

WaterHeating

IHXExV 1

WaterHeating

Entropy in kJ/(kg K)

Tem

pera

ture

in °C

Gas cooler C


Test unit by company thermea. Energiesystemebuilt by ILK Dresden

Heat pump with transcritical semi-hermetic radial piston compressor

Heat Pumps


Air Conditioning

Building air conditioning with transcritical semi-hermetic radial piston compressor

Application by company Obrist and Axima (Austria)


Radial Piston Compressor

Piston

Pressure Valve

Drive Shaft

Eccentric Sleeve

System Guide Ring

Suction Valve


Dimension Comparison Compressor

Reciprocating Piston Compressor Radial Piston Compressor

Semi-hermetic Transcritical CO 2 Compressors


Evaporator 1

EV 2Separator

1

3

4

6 7

9

11

12

13

Evaporator 2

5

10

Gas cooler

Oil separator

Ex.V. 4

Ex.V. 1

8

14

EV 1

2

Oil separaterCascade heatexchanger

Accumulator

16

1

23

45

6 7

8

9 1110

14

15 12

13

Enthalpie in kJ/kg

Dru

ck in

bar

16Compressor 1

Compressor 2

Ex.V. 3

Enthalpy in kJ/kg

Pre

ssur

e in

bar

15

CO2

CO2

Supermarket (Cascade)

Normal temperature cooling and low temperature cool ing in separated cooling cycles

HFCor

HCor

R717or

R723


Supermarket (Booster-System)

EU-Life Project

Normal temperature cooling and low temperature cool ing in one cooling cycle

Enthalpie in kJ/kgD

ruck

in b

ar

2

1

34

567

89

10 11

12

13

14 15

R744

Evaporator 1

EV 2

Separator

1

34

6

7

9 11

12 13

15

Evaporator 2

5

10

Gas cooler

IHXCompressor 2

Compressor 1

Oil separator

ExV 2

ExV 1

8

14

EV 1

2

Enthalpy in kJ/kgP

ress

ure

in b

ar

Heat recovery



System by company KNUDSEN KØLING (Denmark)

Supermarket with semi-hermetic sub- and transcritical compressors

EU-Life Project


System by company GREEN & COOL (Sweden)

Supermarket with semi-hermetic sub- und transcritical compressors



Optimization with Air- and Suction Gas-cooled CompressorsP

ress

ure

Enthalpy

R744

1

22

1


Pressure

Enthalpy

R744

1

22

1

+ Higher suction density → higher mass flow rate → higher cooling capacity

+ Lower compressor discharge temperature

+ Reduced power consumption

+ Higher overall COP of the system

- Lower heating power at heat recovery system at the gas cooler

Optimization with Air- and Suction Gas-cooled Compressors


Air-Cooled Semi-Hermetic CO2 Compressor

Air ducting cover

Fan

Air flow

Electric motor


20

30

40

50

60

70

80

90

100

110

120

130

140

5 10 15 20 25 30 35 40 45 50 55

pH

D [b

ar]

po [bar]:

to [°C]:0 10 15-20-40 -10

Operating Limits of Suction gas- and Air-cooled Semi-

hermetic Compressors

Suction gas-cooled

20

30

40

50

60

70

80

90

100

110

120

130

140

5 10 15 20 25 30 35 40 45 50 55

pH

D [b

ar]

po [bar]:

to [°C]:0 10 15-20 -10-40

air-cooled

Ideal

discharge

pressure

tga = 40 °C

Operating limits suction gas-cooled compressors

+ air-cooled compressor


COP Increase

to = -10 °C

pv2 = 90 bar

tga = 35 °C

11,2 %

COP increase with an air-cooled CO2 compressor

compared to a suction gas-cooled CO2 compressor


Reduction of the Discharge Temperature

Reduction of the discharge temperature with air- cooled CO2

compressors compared to a suction gas-cooled CO2 compressor


Conclusion

• CO2 is already successful operating in many different systems

• CO2 as refrigerant has a lot of developing capabilities

• CO2 is not a refrigerant for universal application

• In many applications air-cooled compressors have clear advantages

in higher COP and lower discharge temperature

• Individual compressor solutions are necessary

• An extended supply of compressors and components is essential


Thanks a lot for

your attention!

Latest Developments in Compressors & Refrigeration Systems ... · Bock GLC 2010 –14.04.2010...

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