Evidence shall show that knowledge has been acquired of safe working practices and determining the basic operating conditions of vapour compression systems. All knowledge and skills detailed in this unit should be contextualised to current industry practices and technologies. KS01-EJ103A Basic operating conditions of vapour compression systems Evidence shall show an understanding of basic operating conditions of vapour compression systems, applying safe working practices and relevant Standards, Codes and Regulations to an extent indicated by the following aspects: T1 Refrigeration Industry The history of the refrigeration industry (note that A/C is covered in another unit) Applications, classifications and equipment used in the refrigeration industry T2 Introduction to the Vapour Compression System Basic Operation Major Components T3 Heat Matter (atoms, molecules, energy and its different forms) Heat energy (definition, unit of measurement) Enthalpy (definition, unit of measurement) Heat flow (hot to cold) Heat transfer methods (conduction, convection, radiation) requirements effects T4 Temperature and relative humidity Temperature Scale types (imperial, metric, absolute) and their units of measurement Conversion to/from absolute values Temperature difference/change (td, Δt, unit of measurement) Relative humidity Thermometer types and applications (digital, stem, dial, max/min, non-contact, data loggers) Relative Humidity measurement devices and applications (dry bulb/wet bulb, sling, digital) Hazards and related safe working practices (working near rotating machinery - fans, pulleys, belts etc) Care and maintenance (bending stems, overheating, removing batteries after use, uncoiling capillary) Calibration (boiling water, iced water, send to a specialist etc) Appropriate and safe methods of use Typical locations on a system Fitting temperature and relative humidity instruments T5 Sensible and Latent Heat Definition of specific heat capacity, latent heat and sensible heat (including units of measurement) Types of latent heat Heat calculations T6 Pressure Define Scale types (imperial, metric, absolute) and their units of measurement Vacuum scales (Pascals, microns) Conversion to/from absolute values The basic Gas Laws – Boyles, Charles and Daltons (excl combined or general gas law) Pressure gauge types and applications (pressure, compound, vacuum, manometer, magnehelic, barometer) Hazards and related safe working practices (dangerous system pressures) Care and maintenance (ingress of oil and contaminants (dirt), avoiding needle bounce (esp. HP) etc) Calibration (atmospheric pressure, send to a specialist etc) Appropriate and safe methods of use Typical locations T7 Refrigerant conditions Saturation temperature Saturated liquid / saturated vapour Superheated vapour Sub-cooled liquid Pressure temperature relationships P/T charts Enthalpy T8 The vapour compression cycle Primary system components High and low pressure sides Basic system operation T9 Working safely with refrigeration vapour compression systems Risk management principles and processes Hazards and risk control measures associated with: refrigeration vapour compression systems and components refrigerants measuring and testing equipment T10 Leak detectors Detector types and applications (electronic, halide, bubble, ultra violet) Hazards and related safe working practices (working around rotating machinery, open flame, ultra violet light etc) Care and maintenance (delicate electronic equipment, changing sensor tip filters, changing gas cartridges etc) Calibration (auto calibrating , send to a specialist etc) Leak detection procedures T11 Service gauges Service Gauges Types (dial gauges or electronic, manifolds with additional vacuum and charging ports & sight glasses) Typical uses for service gauges (high & low side pressure readings, charging, evacuating) Care and maintenance (oil and contaminants (dirt) in hoses, avoiding needle bounce, changing hose seals) Calibration (hoses open to atmosphere, adjusting screw etc) Hose shut-off valves and adaptors (access control valves, kwik couplers, Hansen lines etc) System Access Fittings Types (Schrader, piercing, service valve, post valve, quick couplers etc) Typical applications for each Hazards and related safe working practices (oil or liquid spray, keeping clean, leaks etc) Care and maintenance (gland nuts loosened/tightened, seal caps fitted, regulations on piercing valves) Using Service Gauges Service gauge manifold hose fitting Purging Pressure readings Service gauge manifold hose removal Pressure to temperature conversion T12 Refrigeration Compressors Function of the compressor Compressor styles (open drive, semi-hermetic, hermetic) Types, construction and their applications (reciprocating, rotary, centrifugal, screw, scroll) Basic types of compressor oil (Mineral, Polyolester (POE), Alkyl Benzene, Polyalkylene Glycols (PAG)) (brief overview - covered in more detail in J8) Methods of lubrication (splash, forced) Safe handling (MSDS - POE's, PAG's, Mineral, AB's - Residual acid's in used oil) T13 Condensers and related components Function of the condenser Types, construction and their applications (static, forced draught, water cooled) Function of a cooling tower Types, construction and their applications (natural, induced, forced, evaporative) Function of water pumps Basic Types and their applications Function of liquid receivers Types, construction and their applications (horizontal, vertical, combined condenser/receivers) T14 Evaporators and related components Function of the evaporator Evaporator styles (direct expansion, flooded) Types, construction and their applications (static, forced draught, water cooling) Refrigerant/air/water flow paths (forced/induced draft, parallel/counter flow) Need for water treatment in water systems Methods used to provide water treatment (brief overview) Regulations governing water treatment (brief overview) Secondary refrigerants (brief overview) Properties & applications of secondary refrigerants (water, sodium/calcium chloride, ethylene/propylene glycol) Hazards associated with their use (MSDS) T15 Common Refrigerant Metering Devices Function of a refrigerant metering device Overview of common types and their applications (capillary tube and TX Valve) T16 Basic Operating Conditions Ambient conditions Common climate values (highest max temp, lowest min temp, mean daily temp, mean highest/lowest) Typical climates for various common localities Evaporator Td Effect of changes in Evap. Td and typical industry reference values for water cooled, forced draught and static coils Condenser Td Effect of changes in Cond. Td and typical industry reference values for water cooled, forced draught and static coils Typical storage conditions (temp & RH) for common products (dairy, produce, meat and frozen food rooms) Typical high and low side system operating values (pressures and temperatures allowing 1K equivalent PD) |