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dc.contributor.advisorTassou, SA-
dc.contributor.authorGrace, Iain Nicholas-
dc.descriptionThis thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.en_US
dc.description.abstractThe impact of refrigeration systems on the environment can be reduced by the use of alternative reffigerants which are less harmful to the atmosphere and the optimisation of systems and control strategies to deliver increased levels of energy efficiency. Mathematical modelling offers the opportunity to test the performance of systems under different operating conditions and with alternative refrigerants. Dynamic models allow comparison of both transient and steady-state behaviour and this is of particular importance for liquid chillers, since these systems can operate under transient conditions for long periods. This thesis details the development of a general dynamic model for the simulation of liquid chillers. Mathematical models of the reciprocating compressor, expansion valve, evaporator and condenser are presented. The models are integrated to form the overall system model by passing conditions from one component to another. A series of steady-state and transient experimental tests were carried out on a liquid chiller and the model was used to simulate these tests. Validation was carried out by comparison of these measured results to those predicted by the simulation for both the steady-state and transient tests. Once validated, the model was used to investigate the steady-state and dynamic performance of liquid chillers operating with various refrigerants. The effect of the mass of the system refrigerant charge was examined for a number of refrigerants. The steady-state performance for a range of evaporator and condenser coolant temperatures was also investigated. Finally, the effect of different system refrigerants on start-up transients was examined and the losses in cooling capacity due to cycling quantified. The effect of the expansion valve's initial superheat spring setting on the dynamic response and transient losses was also investigated.en_US
dc.publisherBrunel University School of Engineering and Design PhD Theses-
dc.subjectAlternative reffigerantsen_US
dc.subjectEnergy efficiencyen_US
dc.subjectLiquid chillersen_US
dc.subjectSteady-state performanceen_US
dc.subjectDynamic state performanceen_US
dc.titleModelling the performance and dynamics of vapour compression refrigeration systemsen_US
Appears in Collections:Brunel University Theses
Mechanical and Aerospace Engineering
Dept of Mechanical Aerospace and Civil Engineering Theses

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