22-12-2012, 04:28 PM
Development of a Capillary-assisted Evaporator Used in Adsorption Cooling Systems
General Description:
Capillary-assisted evaporators have drawn a lot of attention recently due to their high heat transfer coefficient benefitting from the extremely thin evaporating liquid film. They are studied widely in fundamental research on heat and mass transfer. Effort has been made to develop capillary-assisted evaporators that have enhanced evaporation rate.
Existing systems, low pressure evaporators such as water evaporators, falling film evaporators and methanol evaporators have two main problems: one is that the system becomes may become more complex involving a circulating pump and liquid spray equipment; the other is the non-uniform liquid distribution on the outside surface of the heat transfer tubes.
However, capillary-assisted evaporation systems can solve these two problems perfectly and thus have the potential to be a more suitable heat transfer method for low pressure and compact evaporators. Moreover, the evaporation coefficient could be greatly enhanced by at least 30-40%. They also possess many advantages such as high heat transfer efficiency, high reliability, structural simplicity and low cost. Most importantly, the special cooling power (SCP) of adsorption cooling systems could be increased by 30-40% due to the large evaporating mass flow rate in capillary-assisted evaporators.
Scope of Work:
1. Design and fabrication of the capillary-assisted evaporator used in adsorption air-conditioning systems
2. Design and fabrication of the capillary-assisted flow and evaporation inside circumferential rectangular micro grooves, etc.
3. Experiments and performance evaluation (e.g. a comparison between the traditional evaporator and capillary-assisted evaporator, heat transfer coefficient performance, etc.)
4. Test its performance under an application of an adsorption cooling system
Some of the above scopes will involve all students working together. Then the students will be assigned individual tasks. Both laboratory-based experimental work and system fabrication in the mechanical engineering workshop will be required.