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Technical
SAVE TIME DESIGNING A LIQUID CHILLER WITH THE NEW BITZER SOFTWARE
By Patrick Burke , SAIRAC Fellow
The following article is a follow-up to the technical article ‘ A case for gas engine VRF systems ’ written by Patrick Burke in the RACA Journal April issue .
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Precisely co-ordinated components deliver improved energy efficiency and make installation and maintenance easier .
The design phase is often time-consuming and complex , but not with the support of the new BITZER SOFTWARE – explained here using liquid chiller design as an example .
An air-conditioning system has to be planned for an office building . The specifications : the water-cooled liquid chiller has to run on a propane compact screw compressor and have a refrigerating capacity of 300kW . But what components are best suited to working together and delivering exceptional energy efficiency ? The fully reworked BITZER SOFTWARE can answer these questions in minutes .
For over 35 years , BITZER SOFTWARE has helped users select and find the optimal combination of compressors and components from the wide product range of BITZER . Relaunched in December
RACA Journal I July 2024
2023 , it is now even more clearly structured and optimised for mobile devices . In January and February 2024 alone , BITZER SOFTWARE performed more than 500 000 calculations and generated more than 20 000 project data sheets . SQD shell and tube evaporators are an important new product group .
QUICK OVERVIEW OF OPERATING PARAMETERS In the example at hand , we intuitively enter BITZER SOFTWARE through the ‘ Compact screw compressor ’ module to design the compressor in stage one . It takes just a couple of clicks to set the chosen refrigerant ( R290 ), the required refrigerating capacity ( 300kW ) and other project specifications :
• Evaporation temperature + 4 ° C ( water flow temperature + 7 ° C )
• Condensing temperature + 38 ° C
• Liquid subcooling 3 K
• Usable suction gas superheat Δtoh 5 K The software then suggests two compatible compressor designs for the planned airconditioning system : the CSHP8553 with the required capacity and the CSHP8563 with somewhat greater capacity . It can pay off to select a slightly smaller compressor with economiser mode , especially if the maximum refrigerating capacity is only needed rarely or for short durations . In no time at all , the calculation provides the user with an overview of the key system parameters under the given operating conditions , such as cooling capacity or power input , coefficient of performance COP and discharge gas temperature .
In this case , the user chooses the CSHP8563-125P-40P compact screw compressor with a refrigerating capacity of 312kW . The software updates the schematic of the refrigerant circuit and makes all data
www . refrigerationandaircon . co . za