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A COMPUTER PACKAGE FOR DAIRY PLANT REFRIGERATION SYSTEMS. Q. Tuan Pham University of New South Wales. Summary. Software has been developed at UNSW under a DRDC-funded project to simulate refrigeration systems We report test results and potential uses in design, operation and optimisation.
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A COMPUTER PACKAGE FOR DAIRY PLANT REFRIGERATION SYSTEMS Q. Tuan Pham University of New South Wales
Summary • Software has been developed at UNSW under a DRDC-funded project to simulate refrigeration systems • We report test results and potential uses in design, operation and optimisation
Rationale • 30 to 50% of electricity in dairy industry is used in refrigeration • Staff are more concerned with production than with energy efficiency • Most industrial refrigeration systems can improve their energy efficiency by about 10 to 15% with negligible capital spending. • Software helps identify possible savings and inefficiencies
A simple refrigeration system Generating cold Using cold
Generating cold A dairy plant refrigeration system Using cold
Energy saving 1: Generation of cold • Proper selection of compressors, condensers • Better operation of engineroom (compressor schedule) • Maintenance of equipment, e.g. • prevent condenser fouling • remove noncondensables (air) • Improved control in engineroom, applications • Energy recovery
Energy saving 2: Use of cold • Improved chilling and freezing methods • Better chiller and freezer designs • Shifting loads to reduce peak loads • Eliminating wastages, e.g. • door infiltration • excessive fan heat • poor insulation
Example: non-optimal cooling regime FAST COOLING: High energy cost Quality problems OVER-DESIGN: Capital cost $$$ Product heat load Optimum UNDER-DESIGN: Operational problem SLOW COOLING Quality/safety problems Compliance problems Cooling/freezing time
Simulation software • General purpose simulation software: Aspen Plus, Hysim... • General purpose refrigeration software: RADS • Industry-specific refrigeration software: DRDC-UNSW suite
What software can do • Predicting changes to refrigeration requirements with • changes in processing operations • changes in product type or throughput • Comparing predicted with actual power consumption - identify wastage • Suggesting alternative schedules for freezers and chillers to reduce peak power charges
Organisation of programs User inputs Outputs: Application heat load Plant heat load Power consumption Graphs, reports
Validation Tests: Objectives • Check that all applications can be modelled • Check that accuracy is acceptable • Check ease of use and robustness
Using the Software in Optimisation • Design of new refrigeration plants • Upgrading of plants • replacement of old equipment • new products • changed flowrates • new processes • changes in schedules
Using the Software in Optimisation (cont) • Checking performance to pinpoint defects • Optimising design and operation • Reschedule applications to shift peak load? • Turn off fans and refrigerators temporarily? • One big compressor or several small ones? • One or two stage compression?
Acknowledgments Dairy Research & Development Corporation Dairy Process Engineering Center Dairy Farmers
To describe an Application... Clicking on 1 starts APDATA.EXE Clicking on ”Help" brings up... Clicking on "Create a Chiller" brings up... Clicking on ”Page 8" brings up...
To describe a Plant... Clicking on 3 starts PLANT.EXE Double-clicking on a textbox brings up the Application window Clicking on “Applications” starts the Applications list Enter name of file created by APPLIC.EXE here
To describe an Engineroom... Clicking on p.1 brings up the General Layout window Clicking on 5 starts ENGROOM.EXE Clicking “Details on level 1” brings up...
To describe an Engineroom (cont)... Clicking on 5 starts ENGROOM.EXE Clicking on “Compressor models” brings up the Compressors window Clicking on a textbox to enter models details...
To describe an Engineroom (cont)... Clicking on 5 starts ENGROOM.EXE Click on Operating conditions... Click on a textbox ...
To carry out routine refrigeration calculations ... Clicking on 8 starts basic compression cycle Clicking on 7 starts Basic Refrigeration Calculations Clicking here gives results
This presentation can be downloaded from www.ceic.unsw.edu.au/staff/Tuan_Pham/ (go to bottom of page) That’s it folks! tuan.pham@unsw.edu.au