This subject treats vapour compression and vapour absorption refrigeration systems. It examines refrigeration plant components on liquid chiller and heat pump applications. It evaluates appropriate refrigerants for specific applications and covers the design of minimum energy use and applicable refrigeration and cooling systems.
The Module will:
- Bring the student to a suitable level of knowledge and understanding of the principles of the subject matter.
- Develop in the student an appropriate level of competence in the descriptive, analytical and computational elements of the subject.
- Enable the student to apply the subject material in the design and optimisation of engineering solutions.
Heat exchangers: evaporator and condenser types, heat transfer coefficients, extended surface, fouling factor.
Expansion devices: capillary tubes, constant pressure expansion valves, float valves, thermostatic expansion valves and electric expansion valves.
Refrigeration compressors: multi-pressure systems, vessel design, ammonia versus other refrigerants.
Refrigerant pipework: practical pipe design and sizing, multiple evaporator coils, oil return.
Absorption refrigeration: cycle description, COP of an ideal absorption cycle, equilibrium properties of LiBr/water solutions, crystallisation, cycle calculations, capacity control, combined absorption/vapour compression system, multiple effect system, vapour recompression system, aqua ammonia system.
Refrigerant pipework: practical pipe design and sizing, multiple evaporator coils, oil return
Refrigerants: halocarbons, hydrocarbons, inorganic refrigerants, azeotropes, ozone depletion and global warming, physical, chemical and thermodynamic characteristics, refrigerant behaviour with oil, secondary refrigerants.
Heat pumps: reversible cycle, heat sources and sinks, performance factor, comparative heating costs, centralised heat recovery systems, VRV systems.
Heat rejection devices: cooling towers, dry and evaporative cooler and condenser, range and approach, analysis of counter flow cooling tower, predicting outlet conditions from a tower, acceptance tests.
Chiller selection: constant and variable volume flow rate systems, piping and control, series and parallel chiller connection, chiller selection criteria.
The methods employed will be a series of lectures, worked examples, problem-solving exercises, practical laboratory exercises and study/reading.
| Module Content & Assessment | |
|---|---|
| Assessment Breakdown | % |
| Formal Examination | 80 |
| Other Assessment(s) | 20 |