| Author | Ubaid-ur-Rehman |
| Call Number | AIT Thesis no.ET-92-23 |
| Note | A thesis submitted in partial fulfillment of the requirement for the degree of Master of Engineering |
| Publisher | Asian Institute of Technology |
| Abstract | The shortages and limited reserves of nonrenewable sources of energy have promp ted interest in t he recovery of waste h eat. Wa s t e hea t recoverv is often one of the most feasible energy conservation opportunities i dentified duri ng energy s urveys. Hea t exchongers are required to recover t h.is waste 11 ea t. In the present study a th eoreti cal and experimenta l study j s carried out. on two h ea t. exdrnngers, a moving bed heC:tt. exchanger and gravity-assi sted hea t pipe heat exchanger, to determine their effectiveness in recovering wast e heat. Mode l s for outside heat transfer coefficient and thermal perfor man ce of moving bed heat exchangers are devel oped. In outside h eat transfer coef ficient mod el particle convection :i. s con sidered as t h e predomi nant mode of h eat tr·an sfer in gas-solid beds of s mall particles. The me ch a nisrn of heat transfer is uns teady-.s t a te conduction between the h eat tr ansfer s urface and the hot bed particl es . The features of the con tacting process are incorporated into the packet heat tran sfer rn odel o .E Baskakov e t al (1973 ) , ancl expression for t h e h eat t ransfer coeffi cient is derived. Experimental st ud ies were performed to test the va licli ty of t he model. A correction f ac tor \vas opplied to the model. The predict ed heat t r ansf er coefficients are then found to be in excel lent agreement. with the measured he at transfer coefficien ts. Simul ation of moving bed heat excrianger model 1.,ias pe:r·formed using four pa rticle type s i. e sand , cast iron, copper a nd l ead, three particl e sizes i . e 1 .4 4 mrn, 0. 6 rn111, 1.0 rnni and three area configurations for water coiJ.s .Th e eff ectiveness of hea t exchanger was found to be around 80-85 % with copper particles. The performance of a n air-to-ai r gravi ty-assisted heat pi pe h e at. exch ang er o:r mul t.ipl e-loop, two- phase t l1er rnosyphon heat exchanger systelll, utilizing water as i t s working fJ.uid and finned tube coils as i ts evaporator and cond enser, has been s tudi ed experimentall y . It was found that the effective ness of the system was higher for higher quantity of charge and decreased as t he air flow rate increased. |
| Year | 1992 |
| Type | Thesis |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Energy and Climate Change (Former title: Department of Energy, Environment, and Climate Change (DEECC)) |
| Academic Program/FoS | Energy Technology (ET) |
| Chairperson(s) | Bhattacharya, S.C; |
| Examination Committee(s) | Mora, J.C. ;Prida Wibulswas; |
| Scholarship Donor(s) | The Government of Japan; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology |