the district cooling network that outperforms naturally page energy is our future, we must save it!...

THE DISTRICT COOLING NETWORK THATOUTPERFORMS NATURALLY

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ENERGY IS OUR FUTURE, WE MUST SAVE IT!EEMOD’S Nantes – 15 / 09 / 2009

>Overall chiller system energy efficiency

1

Sénéjean B, Merchat M, Faurel C, Thibault S, Doucouré A, Benassis F


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> Introduction>

2

• A growing demand for air-conditioning

• EE stakes in chilled water production:

•Controlling the energy consumed by existing systems

•Developing ever more energy efficient systems

•Accordingly, the need to know the true performance of chiller systems

How do we assess the energy efficiency of chilled water

Installations?


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> Indicators>

3

Nominal COP and EER : energy efficiency indicators established by the main installation manufacturer for nominal working conditions

ESEER and SEER : energy efficiency indicators taking part- loading operations into consideration

COP and EER quantified : energy efficiency indicators established as part of this study taking into account the true performances of the installation and its accessories

N.B. The only difference between EER and COP is the units used

EER: btu.hr-1.W-1 COP/ESEER: Wf/We


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>

Measurement equipments : • 31 Temperature sensors

• 12 Wattmeters


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> Specifications for the units selected

5

Building Starting Compr. Refrig.Cooling System

Cooling Power (KW)

Outlet evaporator

water temperatur

e

Inlet condenso

r water temperat

ure

A 2000 6 screw R134A3 cooling towers

1260 5°C 30°C

B 1995 6 reciproc. R222 cooling

towers940 6°C 30°C

C 1990 4 piston R22

2 cooling towers

484 6°C 30°C

D 2008 8 piston R407C1 Dry cooler

776 7°C 25°C

The results provided only concern 4 of the 7 plants equipped with instruments


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> Quantification methods>

6

• Measurements of all electricity consumptions for each appliance

• Measurements of all heating power exchanged at the condensers and at the evaporators

• Readings recorded at 10 minute intervals over the entire year

The overall energy statement is produced


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> Scope of measurements carried out

Water condensers

Air condensers

Performance measurements for all equipment devoted to chilled water production – Does not include distribution

7


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> Weekly results>

8

Results A

0

1

2

3

4

Ja

nu

-08

Fe

b.

Ma

rch

Ap

r.

Ma

y

Ju

ne

Ju

ly

Au

g.

Se

pt.

Oct.

No

v.

De

c.

Ja

nu

-09

Fe

b.

Ma

rch

EE

R a

nd

nb

of

ch

ille

rs

0%

10%

20%

30%

40%

Lo

ad

ing

ra

te

EER Nb of chillers Loading rate

Results B

0

1

2

3

4

Ja

nu

-08

Fe

b.

Ma

rch

Ap

r.

Ma

y

Ju

ne

Ju

ly

Au

g.

Se

pt.

Oct.

No

v.

De

c.

Ja

nu

-09

Fe

b.

Ma

rch

EE

R a

nd N

b o

f c

hille

rs

0%

10%

20%

30%

40%

Lo

ad

ing

ra

te

Nb of chillers EER Loading rate

Results C

0

1

2

3

4

au

g-0

8

se

pt.

oct.

no

v.

de

c.

Ja

nu

-09

Fe

b.

Ma

rch

Ap

ril

Ma

y

Ju

neE

ER a

nd

Av

era

ge

nb

of

ch

ille

rs

0%

10%

20%

30%

40%

Lo

ad

ing

ra

te

EER Nb of chillers Loading rate

Results D

0

1

2

3

4

Au

g-0

8

Se

pt.

Oct.

No

v.

De

c.

Ja

nu

-09

Fe

b.

Ma

rch

Ap

ril

Ma

y

Ju

ne

EE

R a

nd

nb

of

ch

ille

rs

0%

5%

10%

15%

20%

25%

30%

35%

Lo

ad

ing

ra

te

EER Average nb of chillers Loading rate

Characterization of true chilled water production plant efficiency


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>

0,0

0,5

1,0

1,5

2,0

0%

10%

20%

30%

COP système Taux de charge (%)

Example of a fault recorded during Example of a fault recorded during operationsoperations

Control mode modification:

Before After

T° average cond. before January = 34°C

COP < 1

T° average conditions after January = 21°C

COP > 1

The operator has no measurement instruments = Plant operation is not optimised

9


PAGE


>

The average loading rate per machine is kept at a very low level =Performances deteriorate

Example of a fault recorded during Example of a fault recorded during operationsoperations

0%

4%

8%

12%

16%

20%

Fév. Mars Avril

1 000

5 000

9 000

13 000

17 000

Chillers loading rate (%) Energy produced (MWhf)

10


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> Results – Distribution of units consuming energy

49% of the electricity consumed by the plant investigated is consumed by the accessories

11

Other9%

Condensor pumps

8%

Evaporator primary pumps

19%

Cooling towers13%

Chillers51%


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> Summary of results>

12

The results reveal major differences between measurements carried out and nominal performance levels


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> Conclusions>

13

• Few or no measurement instruments on most of the installations

• True performance levels can only be assessed by carrying out of measurements over sufficiently lengthy periods of time

• The impact made by the operation cannot be assessed using tests of numerical simulation


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> Outlook>

14

Measurements

Measures should be carried out on a wider sample of installations

Equipment

The need for specific meters for recording energy consumption and chiller energy produced by the installations

Assessments and comparisons

• of the various technical solutions

• of the retrofit impact on installations involving HCFC

• of stand-alone installations and of centralised installations

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