Maciel- CO2 Seminarin Milan - Embraco

7/27/2019 Maciel- CO2 Seminarin Milan - Embraco

1/16

POTENTIAL OF CARBON DIOXIDE COMPRESSOR TECHNOLOGY

FOR REFRIGERATION APPLIANCES


2/16

Outline

New Applications for an Old Refrigerant

Making CO2 Refrigeration Technology Feasible

Performance Assessment and Perspectives

Preliminary Results from Appliances Tests

Closure


3/16


CO2 Refrigeration advertisement ina business magazine in 1921:

1 to 150 tons in single units

The ideal equipment for Refrigerationpurposes

Carbonic Safety System

Source:South Central Library Systems website

Usage in the Past


4/16


CO2 Replacement - CFCs Era Begins

CFC granted patent by ThomasMidgley in 1931:

...a process of heat transfer in whichthese desirable properties, such as

non-flammability and non-toxicity, areobtained in combination with the

desired boiling point.

Source: United States Patent Trade Office


5/16


Reasons:

International regulations on HFCs

Lack of long term solutions for refrigerant fluids

Environmental consciousness

Ecological appeal

Market demand

Applications Envisioned:

Automobile Air-Conditioning

Heat Pump Water Supply Systems

Light Commercial Refrigeration (Beverage Cooling, Ice Cream

Freezing, ... )

CO2 Revival


6/16


Refrigeration Means with Practical Use

Vapor Compression

Vapor Absorption

Air-Cycle Solid State (Thermo-Electric, ...) High Efficiency

Low Cost

Better Cost-to-Benefit Ratio

Simple Mechanical Embodiments

...the refrigerating effect is produced by making a volatile fluid boil

at a suitably low temperature...


7/16


Vapor Compression Systems


8/16


Refrigeration Cycle Inefficiency

Typical conditions for MBP Application


9/16


TEWI Methodology

En1mGWPnLGWPTEWI )(

Direct Effect

GWP - Refrigerant Global Warming

Potential [kgCO2/kg]

L - Annual Leakage Rate [kg/year]n - Life time [years]

m - Refrigerant charge [kg]

- Recycling factor [%]

Indirect Effect

E - Annual energy consumption [kWh/year]

- CO2 emissions on energy generation[kgCO

2/kWh]

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

100.0

Emissions[kgCO2]

TEWI Analysis for a Light Commercial Refrigeration Appliance

R134a/32oC Ambient Temperature/15 YearsLi fetime/75% Refrigerant Recovery Factor

TEWI Analysis 0.7 99.3

Direct Global Warming Potential [% of Total

CO2 Emission]

Indirect Global Warming Potential [% of Total

CO2 Emission]


10/16


Overcoming Inefficiency of the CO2 Refrigeration Cycle

32oC Ambient Temperature

65% Relative Humidity


11/16


Phase I: CO2-Oriented Compressor Design

Results Efficiencies

560.38

1.42

394.00 -

70.92 82.0%

21.28 93.4%

301.80 62.1%

4.50 -

6.60 -

290.70 -

70.82 -

32.42 -

187.46 35.02%

121.81 -

65.65 -

Isentropic Power [W]

Cycle Power [W]

Carnot Power [W]

Discharge [W]

Effective Power [W]

Other Thermod. [W]

Superheating [W]

Motor [W]

Mechanical [W]

Indicated Power [W]

Suction [W]

CO2 Prototype

Name

Total Power [W]

Cooling Capacity [W]

COP [W/W]


12/16


Phase II: CO2-Optimized Compressor Design

Results Efficiencies

683.29

1.71

398.70 -

- 82.00%

- 92.92%

- 75.24%

- -

- -

- -

- -

- -

228.58 35.02%

148.53 -

80.05 -Carnot Power [W]

Superheating [W]

Other Thermod. [W]

Isentropic Power [W]

Cycle Power [W]

Indicated Power [W]

Suction [W]

Discharge [W]

Effective Power [W]

Name

Total Power [W]

Motor [W]

Mechanical [W]

Cooling Capacity [W]

COP [W/W]

CO2 Prototype


13/16


Compressor Data - Baseline and BenchmarkCompressor Model T 6213Z CO2 Phase I CO2 Phase II

Refrigerant fluid R134a R744 R744

ApplicationLight commercial

M-HBP

Light commercial

MBP

Light commercial

MBP

Version 220-240 V / 50 Hz 220-240 V / 50 Hz 220-240 V / 50 Hz

Evaporating temperature [ oC ] -10.0 -10.0 -10.0

Condensing temperature [ oC ] 42.0 85 bar (*) 85 bar (*)

Return temperature [ oC ] 32.0 32.0 32.0

Liquid temperature [ oC ] 32.0 32.0 32.0

Cooling capacity [ W ] 767.0 676.8 756.3

COP [ W/W ] 1.866 1.560 1.740

Compared to T 6213Z (Baseline) 0.0% -16.4% -6.8%

(*) Reference Pressure - only for Thermodynamic cycle comparison


14/16

Preliminary Results from Appliance Tests

Beverage Cooling - 405 Cans Vending Machine

32oC Ambient Temperature

65% Relative Humidity337.7

334.3

306.8

275.0

290.0

305.0

320.0

335.0

350.0

T6213Z (R134a) CO2 Phase I CO2 Phase II

EnergyConsumption[kWh/month

]


15/16

Closure

Concluding Remarks

All the comments stated below take into account HFC technology currently in the field,

without considering any improvement on it;

Replacing current HFC refrigerant fluids by CO2 is meaningful only if the overall energy

consumption is at least at the same level of the respective baseline;

Theoretical CO2 refrigeration cycles point to efficiencies lower than their respective HFC

cycles; the higher the ambient temperature the higher the penalty in efficiency is;

In real applications, optimized CO2 compressors can deliver better compression and

volumetric efficiencies than current HFC compressors;

Superior compression and volumetric efficiencies can make the CO2 application feasible,

overcoming the intrinsically low cycle efficiency;

Preliminary results from an appliance testing employing optimized CO2 compressors have

pointed to competitive performance in terms of energy consumption;


16/16

QUESTIONS ?Contact Information:

Ricardo Maciel

EMBRACO - Empresa Brasi le ira de Compressores SA

Rui B arbosa 1020 - Costa e Silva

Joinv i l le - SC - BrazilPho ne: +55 47 441.2762

Fax: +55 47 441.2650

email: r [email protected] .br

Maciel- CO2 Seminarin Milan - Embraco

Documents

Transcript of Maciel- CO2 Seminarin Milan - Embraco