Development of a triple stage heat transformer for the recycling of low temperature heat energy

Show simple item record

dc.contributor.advisor Byrne, Edmond P. en
dc.contributor.advisor Cronin, Kevin en Donnellan, Philip 2015-10-23T09:14:55Z 2015-10-23T09:14:55Z 2014 2014
dc.identifier.citation Donnellan, P. 2014. Development of a triple stage heat transformer for the recycling of low temperature heat energy. PhD Thesis, University College Cork. en
dc.identifier.endpage 240
dc.description.abstract Absorption heat transformers are thermodynamic systems which are capable of recycling industrial waste heat energy by increasing its temperature. Triple stage heat transformers (TAHTs) can increase the temperature of this waste heat by up to approximately 145˚C. The principle factors influencing the thermodynamic performance of a TAHT and general points of operating optima were identified using a multivariate statistical analysis, prior to using heat exchange network modelling techniques to dissect the design of the TAHT and systematically reassemble it in order to minimise internal exergy destruction within the unit. This enabled first and second law efficiency improvements of up to 18.8% and 31.5% respectively to be achieved compared to conventional TAHT designs. The economic feasibility of such a thermodynamically optimised cycle was investigated by applying it to an oil refinery in Ireland, demonstrating that in general the capital cost of a TAHT makes it difficult to achieve acceptable rates of return. Decreasing the TAHT's capital cost may be achieved by redesigning its individual pieces of equipment and reducing their size. The potential benefits of using a bubble column absorber were therefore investigated in this thesis. An experimental bubble column was constructed and used to track the collapse of steam bubbles being absorbed into a hotter lithium bromide salt solution. Extremely high mass transfer coefficients of approximately 0.0012m/s were observed, showing significant improvements over previously investigated absorbers. Two separate models were developed, namely a combined heat and mass transfer model describing the rate of collapse of the bubbles, and a stochastic model describing the hydrodynamic motion of the collapsing vapour bubbles taking into consideration random fluctuations observed in the experimental data. Both models showed good agreement with the collected data, and demonstrated that the difference between the solution's temperature and its boiling temperature is the primary factor influencing the absorber's performance. en
dc.description.sponsorship Irish Research Council for Science Engineering and Technology (EMBARK initiative) en
dc.format.mimetype application/pdf en
dc.language.iso en en
dc.publisher University College Cork en
dc.rights © 2014, Philip Donnellan. en
dc.rights.uri en
dc.subject Energy en
dc.subject Absorption en
dc.subject Bubbles en
dc.subject Heat transformer en
dc.subject Triple absorption heat transformer en
dc.subject Waste heat en
dc.subject Energy recycling en
dc.subject Bubble column en
dc.subject Random processes en
dc.subject Mass transfer en
dc.title Development of a triple stage heat transformer for the recycling of low temperature heat energy en
dc.type Doctoral thesis en
dc.type.qualificationlevel Doctoral en
dc.type.qualificationname PHD (Engineering) en
dc.internal.availability Full text available en No embargo required en
dc.description.version Accepted Version
dc.contributor.funder Irish Research Council for Science Engineering and Technology en
dc.description.status Not peer reviewed en Process & Chemical Engineering en
dc.check.type No Embargo Required
dc.check.reason No embargo required en
dc.check.opt-out Not applicable en
dc.thesis.opt-out false
dc.check.embargoformat Not applicable en
dc.internal.conferring Spring Conferring 2015

Files in this item

This item appears in the following Collection(s)

Show simple item record

© 2014, Philip Donnellan. Except where otherwise noted, this item's license is described as © 2014, Philip Donnellan.
This website uses cookies. By using this website, you consent to the use of cookies in accordance with the UCC Privacy and Cookies Statement. For more information about cookies and how you can disable them, visit our Privacy and Cookies statement