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Building Energy Auditing DEPARTMENT OF MINERALS AND ENERGY DME-Danida Capacity Building in Energy Efficiency & Renewable Energy Energy Assessment and Savings Opportunity Identification Module 1: A Context for Building Energy Audits DEPARTMENT OF MINERALS AND ENERGY DME-Danida Capacity Building in Energy Efficiency & Renewable Energy Energy Efficiency in South African Buildings Module 2: Basic Principles of Energy DEPARTMENT OF MINERALS AND ENERGY DME-Danida Capacity Building in Energy Efficiency & Renewable Energy Understanding how energy works in buildings Learning objectives DEPARTMENT of MINERALS and ENERGY  Define energy in its various forms and energy related properties;  Use the correct units for energy and power, and convert from one unit to another as needed;  Determine the properties of steam and moist air;  Describe the mechanisms by which heat is transferred;  Explain the effect of insulation on heat transfer, and the means by which radiative heat transfer is controlled DME Building Energy Audit Cours e Energy in its various forms DEPARTMENT of MINERALS and ENERGY  Chemical – in fuels  Thermal – sensible and latent  Mechanical  Electrical Energy Equivalents 1000 joules (J) kilojoule (kJ) kilowatt-hour (kWh) 3,600,000 J or 3.6 MJ DME Building Energy Audit Cours e Basic electricity DEPARTMENT of MINERALS and ENERGY  Voltage This is what pushes electricity through a circuit the “driving force” Units are Volts (V)  Current This is what is pushed through by the voltage the “flow” Units are Amperes (A) (“Amps”, for short) DME Building Energy Audit Cours e Electrical power DEPARTMENT of MINERALS and ENERGY When voltage and current work together to something useful - such as turn a motor or light a lamp  Units are Watts  1000 Watts = kilowatt (kW)  horsepower (HP) = 746 Watts DME Building Energy Audit Cours e AC/DC DEPARTMENT of MINERALS and ENERGY 220 volts DC vs time 310 220 220 220 volts RMS 0 -310 DME Building Energy Audit Cours e 1/50 sec Calculating power DEPARTMENT of MINERALS and ENERGY Watts = Volts x Amps x Power Factor  VA = Volts x Amps Power factor (PF) indicates how well the current andLamps voltage 100% are working Incandescent together Large Motors 80-90% Small Motors DME Building Energy Audit Cours e 60-75% Power Factor - lagging current 310 310 220 220 0 -310 DEPARTMENT of MINERALS and ENERGY -310 DME Building Energy Audit Cours e 10