UEERA0042 — Evaluate thermodynamic and fluid parameters of refrigeration systems

Elements & performance criteria

Performance evidence

• determining the extent of the evaluation
• setting up and conducting appropriate examinations and tests
• documenting evaluation results for use in design work
• dealing with unplanned events
• applying environmental and sustainable energy principles and practices
• applying relevant legislation, industry standards, codes of practice and regulations
• applying relevant work health and safety (WHS)/occupational health and safety (OHS) requirements, including: - applying safe working practices - hazard identification and reporting - implementing risk control measures - determining need to test or measure live work
• documenting results of evaluation
• evaluating fluid and thermodynamic parameters of refrigeration systems
• performing fluid and thermodynamic evaluation tests
• preparing to evaluate fluid and thermodynamic parameters of refrigeration systems
• reporting on evaluation of fluid and thermodynamic parameters of refrigeration systems

Knowledge evidence

• thermodynamics and fluid fundamentals, refrigeration engineering mathematics, safe working practices and relevant standards, codes and regulations, including: - matrices: - the operations: addition (subtraction), scalar multiplication and matrix multiplication up to 3x3 matrices - identity matrix and inverse matrix - elementary algebraic manipulation of matrices - solve up to three equations (linear) in three unknowns using inverse matrices and determinants - quadratic functions: - graphs of quadratic functions represented by parabolas and significance of the leading coefficient - zeros represented graphically - quadratic equations by factoring and quadratic formula - simultaneously linear and quadratic equations algebraically and geometrically - engineering mathematics - B - exponential and logarithmic functions: - laws of indices - graph of f(x) = kabx, emphasising a = 10, e - definition of the logarithm to any base - graph of f(x) = k loga bx, emphasising a = 10, e - solve exponential and simple log equations using indices, logs, calculator and graphically - change of log base, emphasising 10 and e - growth and decay - trigonometric functions: - the ratios: sin, cos, tan, cosec, sec and cot - degrees, radians - graphs of k f(ax + b) where f(x) = sin x, cos x, tan x, and significance of k,a,b, for example V = Vm sin (wt+ f) - trigonometric identities - energy and humanity: - need for energy and relationship between energy usage and standard of living - energy conversion - typical processes and efficiencies - sources of energy - solar energy - direct heating, photosynthesis, solar cells, power tower, hydrogen for solar energy, ocean thermal energy collector, solar ponds, wind and wave energy, and hydro-electric power - geothermal energy - tidal energy - nuclear energy - fission and fusion, burner and breeder reactors - stored fuel reserves - fuel conservation - reduction in wastage, recycling, greater usage efficiency and use of waste heat - thermodynamics - basic concepts: - nature of matter - atoms, molecules, inter-molecular forces, molecular motion and states of matter - mass and conservation of mass principle - volume, density, specific volume and relative density - force, weight and pressure (atmospheric, gauge and absolute) - temperature (Celsius and Kelvin) - systems and black box analysis - reciprocating piston and cylinder mechanism – pressure ratio and compression ratio - energy: - definition and principles - potential energy - kinetic energy - work (linear and rotational), constant and variable force, relationship to pressure and volume change - power (linear and rotational) - sensible heat - specific heat capacity (constant pressure and constant volume) - latent heat - chemical energy - energy content of a fuel - internal energy - energy transfer in closed and open systems - definition of a closed system - calorimetry as an example of a closed system (with or without phase change) - thermodynamics 1 - non-flow energy equation - typical applications such as stirring with simultaneous heating or cooling - definition of an open system - mass and volume flow rate and continuity equation - steady flow energy equation (negligible change in kinetic or potential energy) leading to the concept of enthalpy - typical applications such as turbines, compressors, boilers and heat exchangers - gases: - definition of a perfect or ideal gas in terms of the molecular model - general gas equation - characteristic gas equation (equation of state) - constant pressure process - constant volume process - isothermal process - polytropic process - adiabatic process - heat engines: - definition of a heat engine - essentials of a heat engine - heat source, heat sink, working substance, mechanical power output and working cycle - energy balance for a heat engine (as a black box) and efficiency - maximum possible efficiency (Carnot efficiency) - types of heat engines according to working substance, heat source, mechanical arrangement and working cycle - typical practical cycles - Stirling, Otto, diesel, dual, two stroke (spark and compression ignition) and Joule cycle - thermodynamics 1 - heat engine performance: - measurement of torque and power output - rope brake, shoe brake, hydraulic dynamometer and electric dynamometer - heat supply rate, efficiency and specific fuel consumption - measurement of indicated power - mechanical indicator, electric/electronic indicator and Morse test - friction power, mechanical efficiency and indicated thermal efficiency - volumetric efficiency - energy balance - performance curves - variable load constant speed, and variable speed constant throttle setting - basic properties of fluids: - description of a fluid and the difference between solids and fluids, liquids and gases, hydraulics and pneumatics - chemical properties, reaction with metals, corrosiveness, flammability, toxicity, pollution and environmental effects - dissolves gases and particles in liquids (slurries) - foaming of liquids: basic properties and units - mass, volume, density, specific volume, relative density, force and weight, pressure (absolute, atmospheric and gauge), temperature (Celsius and Kelvin), viscosity and surface tension - vapour pressure of a liquid - saturation vapour pressure - temperature and pressure effects on the basic properties - ideal/perfect gases and liquids - gas laws for ideal gases - fluid mechanics 1 - components: - pipes, channels, tubes and ducts (rigid and flexible) - valves - gate, globe, non-return/foot, needle, ball, plug cock, diaphragm, pressure regulating/reducing and safety valves - filters and strainers for gases and liquids - gauges and instruments - pressure and temperature gauges, liquid level gauges, thermometers, thermocouples, manometers and piezometers - pipe fittings - elbows/bends, enlargement/contractions, coupler/unions and tees - tanks and vessels - storage tanks, pressure vessels, header and surge tanks, and weirs/dams/reservoirs - nozzles/spray heads - flow measurement instruments - venturi and orifice meters, pitot tube, rotameter and anemometer (fan/hot wire) - pumps/compressors and motors/turbines - actuators - linear (cylinders) and rotary - selection of equipment and instruments considering properties and compatibility - fluid statics: - pressure at a point, direction of pressure on a surface - pressure variation with depth in a liquid - Pascal’s Principle - manometer/piezometer calculations (vertical and inclined) - forces due to fluid pressure on vertical, horizontal and inclined surfaces - centre of pressure - Archimedes Principle - buoyancy, flotation, apparent weight and centre of buoyancy - fluid flow - steady and unsteady flow, streamlines and eddies - velocity - average or mean and local - mass and volume flow rate - conservation of mass leading to the Continuity Equation for fluid flow - modification of the Continuity Equation for volume flow of liquids or gases with small changes in density - Bernoulli Equation for ideal fluids, meaning of pressure, velocity and potential head and total head - causes of head loss and modification of the Bernoulli Equation to include a head loss term for real fluids - fluid power: - definition and units for work, torque and power - relationship between force, velocity and power and torque, angular velocity and power - work done by a gas expanding at constant pressure - relationship between fluid power, mass flow rate and head - relationship between fluid power, volume flow rate and pressure - efficiency of a pump or turbine - modification of the Bernoulli Equation to include a pump or turbine in the fluid circuit as well as a head loss term - forces developed by flowing fluids: - impulse-momentum equation for fluid flow - force developed by a jet striking a stationary plate - perpendicular, inclined or curved - force developed by a jet striking a moving plate or blade - force developed by a jet striking a series of moving plates or blades - power developed and efficiency
• refrigeration system specifications
• relevant manufacturer specifications
• relevant test methods
• relevant WHS/OHS legislated requirements, including: - risk control measures - relevant workplace documentation - relevant workplace policies and procedures

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