Beta 1


Title Integration of Solid Oxide Fuel Cells and Absorption Cooling Units
Author Frimodt, Casper
Mygind, Kim Frithjof
Supervisor Elmegaard, Brian (Thermal Energy Systems, Department of Mechanical Engineering, Technical University of Denmark, DTU, DK-2800 Kgs. Lyngby, Denmark)
Rokni, Masoud (Thermal Energy Systems, Department of Mechanical Engineering, Technical University of Denmark, DTU, DK-2800 Kgs. Lyngby, Denmark)
Petersen, Thomas Frank (Department of Mechanical Engineering, Technical University of Denmark, DTU, DK-2800 Kgs. Lyngby, Denmark)
Institution Technical University of Denmark, DTU, DK-2800 Kgs. Lyngby, Denmark
Thesis level Master's thesis
Year 2010
Abstract It is investigated whether it is feasible to integrate a solid oxide fuel cell (SOFC) and an absorption (ABS) air conditioner (AC). First a market investigation based on rough economical calculations shows that the SOFC-ABS system fits two market segments - Auxiliary Power Unit (APU) for ships and Distributed Generation (DG) for hotels. The latter is the best suited example of an application and will constitute the basis in this project. A thermodynamical zero-dimensional steady state model of the SOFC-ABS system is developed in order to demonstrate the performance of the integrated system. The thermodynamical model is mainly based on theory but also partly on empirical knowledge from the industry. More system configurations are modeled showing that the double stage absorption cycle is the best choice if the inlet air for the SOFC is additionally preheated by the heat from the exhaust gas remaining after the ABS. A wet cooling tower is necessary for the double stage ABS unit if the surrounding temperature is above 20±C - otherwise the desorber temperature will have to exceed the normal limit of 150±C. The system is simulated with a standard parameter configuration, changing one parameter at a time in order to determine its influence on the system performance. Additionally a sensitivity analysis is made in order to determine how crucial the exact values of the estimated parameters are. From these results an optimized parameter configuration is found. In a climate with a temperature of 30±C and relative humidity of 40% a fuel input (methane gas) of 100kW gives 50kW of electricity, 59kW of cooling and 3kW of hot water. Three case studies of hotels in different locations show that the SOFC-ABS system can cope with very hot climates if they are dry. For humid climates the ABS unit can not run at too high ambient temperatures. The thermodynamical model shows that it is feasible to integrate a SOFC and an ABS unit, and the economical calculations indicate that it could be an economical advantage as well.
Abstract Det vil blive undersøgt, om det er muligt at integrere en Solid Oxide BrændselsCelle (SOFC) med et absorptionsairconditionanlæg (ABS). Først laves en markedsundersøgelse på baggrund af økonomiske overslagsberegninger. Denne viser, at SOFC-ABS-systemet passer godt til to markedssegmenter - Auxiliary Power Unit (APU) til skibe og Distributed Generation (DG) til et hotel. Hotellet konkluderes at være det mest egnede til SOFC-ABS-kombinationen, og denne case danner derfor grundlag for resten af projektet. En termodynamisk nul-dimensional steady state model af SOFCABS-systemet udvikles for at beregne ydelsen af det integrerede system. Den termodynamiske model er hovedsageligt baseret på teori men også delvist på empirisk viden fra industrien. Flere forskellige systemkonfigurationer modelleres. Det viser sig, at dobbelteffekt absorptionskredsløbet giver den bedste ydelse. I hvert fald hvis luften til brændselscellen forvarmes af den spildvarme, der er tilbage i udstødningsgassen efter ABS-anlægget. Et vådkøletårn er nødvendigt, hvis dobbelteffekt-ABS-anlægget skal bruges i omgivelser med en temperatur på over 20±C - ellers kommer desorbertemperaturen over de 150±C, der normalt anses for at være den øvre grænse. Systemet er simuleret med en standardparameterkonfiguration, hvorefter en parameter ændres ad gangen for at fastlægge, hvordan den influerer på systemets ydelse. Derudover laves en følsomhedsanalyse for at vise, hvor følsomt systemet er over for den præcise værdi af de skønnede parametre. Ud fra disse undersøgelser findes en optimal parameterkonfiguration. I et klima med en temperatur på 30±C og en relativ fugtighed på 40%, vil det optimerede system, ved et brændselsinput (af metan) på 100kW, give ca. 50kW elektricitet, 59kW køling og 3kW vandopvarmning. Tre cases med hoteller i forskellige egne viser, at SOFC-ABSsystemet er passende til meget varme klimaer, der samtidigt har lav luftfugtighed. Hvis der derimod er høj luftfugtighed, kan absorptionsanlægget ikke køre ved høje omgivelsestemperaturerer. Simuleringerne og beregningerne viser, at det er muligt at integrere en SOFC-brændselscelle med et absorptionskøleanlæg og tyder desuden på, at det også kunne være en økonomisk fordel.
Note The projet is conducted in corporation with Topsoe Fuel Cell.
Imprint DTU Mechanical Engineering : Kgs.Lyngby
Pages 322
Fulltext
Original PDF Integration_of_Solid_Oxide_Fuel_Cells_and_Absorption_Cooling_Units.pdf (5.66 MB)
Admin Creation date: 2011-06-28    Update date: 2011-06-28    Source: dtu    ID: 277914    Original MXD