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Overall chiller system energy efficiency. Sénéjean B , Merchat M, Faurel C, Thibault S, Doucouré A, Benassis F . Introduction. A growing demand for air-conditioning EE stakes in chilled water production: Controlling the energy consumed by existing systems
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Overall chiller system energy efficiency Sénéjean B, Merchat M, Faurel C, Thibault S, Doucouré A, Benassis F
Introduction > • 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?
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
Measurement equipments : • 31 Temperature sensors • 12 Wattmeters
Specifications for the units selected 5 The results provided only concern 4 of the 7 plants equipped with instruments
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
Scope of measurements carried out 7 Water condensers Air condensers Performance measurements for all equipment devoted to chilled water production – Does not include distribution
Weekly results 8 > Characterization of true chilled water production plant efficiency
Control mode modification: 9 Example of a fault recorded during operations 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
10 Example of a fault recorded during operations The average loading rate per machine is kept at a very low level = Performances deteriorate
Results – Distribution of units consuming energy 11 49% of the electricity consumed by the plant investigated is consumed by the accessories
Summary of results 12 > The results reveal major differences between measurements carried out and nominal performance levels
Conclusions 13 > • Few or no measurement instruments on most of the installations • True performance levels can only be assessed bycarrying out of measurements over sufficiently lengthy periods of time • The impact made by the operation cannot be assessed using tests of numerical simulation
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