Introduction to Refrigeration STAR PRODUCTS & SYSTEMS Introduction to Refrigeration Insert Presenter name here

Saturation Temperature Turnover £25m Locations HQ in Glasgow Aberdeen Bristol Derby Leeds Glasgow (branch) London Oxford Newcastle Manchester Established 1970 250 Employees

Introduction A pressure – Enthalpy (P-H) Diagram is a useful device to 2nd Law of Thermodynamics States: “Heat cannot of itself pass from one body to a hotter body” Need to do work to compress this refrigerant gas Refrigeration cycle needs A Compressor A Condenser An Expansion Device An Evaporator A pressure – Enthalpy (P-H) Diagram is a useful device to understand what is happening in the cycle Turnover £25m Locations HQ in Glasgow Aberdeen Bristol Derby Leeds Glasgow (branch) London Oxford Newcastle Manchester Established 1970 250 Employees

Simple Refrigeration System Consist of the following: - Evaporator (low pressure – Liquid to Vapour) - Compressor (low to high pressure – Vapour) - Condenser (high pressure – Vapour to liquid) - Expansion Device (high to low pressure – Liquid) 2 3 High Pressure Liquid High Pressure Vapour Condenser Expansion Device Compressor Turnover £25m Locations HQ in Glasgow Aberdeen Bristol Derby Leeds Glasgow (branch) London Oxford Newcastle Manchester Established 1970 250 Employees Evaporator Low Pressure Vapour 1 4

Thermophysical Properties of Refrigerants Turnover £25m Locations HQ in Glasgow Aberdeen Bristol Derby Leeds Glasgow (branch) London Oxford Newcastle Manchester Established 1970 250 Employees

Pressure-Enthalpy Diagram for R717 Cooling Industry Awards 2005 Installation of the Year - Commercial (Winner) Installation of the Year - Industrial (Winner) 2004 Environmental Pioneer - Refrigeration (Winner)

Points to look for Bar G and Bar A Sensible heat kJ/kg Latent heat kJ/kg Saturated liquid line Saturated vapour line Vapour quality/dryness fraction Compression ratio (CR) Sub cooling Superheat Refrigerating effect (RE) kJ/kg Work done by compressor (WD) kJ/kg Coefficient of performance (COP) COP = RE WD Note: RE x mass flow rate = kJ x kg = kJ = kW kg s s ACR News 2005 Contractor of the Year (>£10m turnover) Environmental Initiatives Award

Bar (G) ACR News 2005 Contractor of the Year (>£10m turnover) Environmental Initiatives Award

Refrigeration cycle R717 (Ammonia) R22 Now let’s consider this refrigeration cycle with two very different refrigerants: R717 (Ammonia) R22 Evaporating pressure bar(A) Evaporating temp °C Condensing pressure bar(A) Condensing temp °C Discharge temp °C Refrigerating effect kJ/kg Specific volume at suction m³/kg Refrigerating effect kJ/ m³ Mass flow rate kg/s 0.715 -40.0 13.5 35.0 90.0 1195.0 1.6 746.9 0.418 1.05 183.0 0.23 795.6 2.73 ACR News 2005 Contractor of the Year (>£10m turnover) Environmental Initiatives Award

Any Questions ? Questions? Turnover £25m Locations HQ in Glasgow Aberdeen Bristol Derby Leeds Glasgow (branch) London Oxford Newcastle Manchester Established 1970 250 Employees