Fans & Pumps
Overview
• • • • • • Introduction Fan & Pump Laws Variable flow methods Energy Saving Mechanical Methods Engineering & Maintenance
Introduction
• The course is intended to familiarise you with the fans and pumps type applications.
Basic Terms
• Flow of gases and liquids is measured in units against time:– cubic meters per minute: cubic feet per minute etc. • Pressure of liquids or gases is measured in units against area:– lbs per square inch: kg per square cm. • Temperature and pressure have a significant effect on gases and liquids.
Glossary of Terms
• There will be various abbreviations used throughout this presentation.
– – – – – – – – – AC DC AHU EMC P&I PID VSD SRD BMS Alternating current Direct current Air handling unit Electro magnetic compatibility Proportional & integral Proportional integral derivative Variable speed drive Switched Reluctance Drive Building Management Systems
What is a Square and Cube Y Law
100 90 80 70 60 50 40 30 20 10 0 0 1 2 3 4 5
3 y=x 2 y=x
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Fan Laws 1
• For a given system in which the pressure loss increases by the square of the flow and without change of density
– The inlet volume varies in proportion to the speed of the fan. – The fan total pressure and static pressure varies as the square of the fan speed. – The air power and the impeller power varies as the cube of the fan speed.
Fan Laws 2
• For a given system in which the pressure loss increases by the square of the flow and with changes of density
– The total fan power, the static pressure and the fan power all vary as the mass per unit volume of the air which, in turn, varies directly as the barometric pressure and inversely as the absolute temperature.
Fan Laws 3
• For geometrically similar airways and fans operating at a constant speed and efficiency with constant air supply
– The inlet volume varies as the cube of the fan size – The total and static air pressure vary as the square...