Analysis of Dryer and Vapor Absorption Refrigeration Systems Powered by Geothermal Energy

Abstract

Geothermal energy, one of the renewable energies in the earth, have extensively been used worldwide. Its applications falls in to two classifications; first, utilizing heat energy in the source directly and second, indirectly converting it in to another energy form (electricity). In Ethiopia, with an estimated geothermal potential of 4200 – 11000 MW, Aluto Langano of Oromia region morethan 7.2 MW of electrical power is existing indirect application. Besides bathing and swimming which are estimated to consume about 2.2 MW, there has been no investigation on direct geothermal energy use in Ethiopia. In this thesis, with an objective to analyze dryer system and vapor absorption refrigeration system (VARS), the systems powered by geothermal energy for thermal applications such as drying of agricultural products and cooling of water, respectively; thermodynamic and mathematical analyses of the systems are separately done. In the first part, when ambient air is forced to flow across the bundle of tubes, heat and mass transfer model is used to quantify amount of heat energy transferred and moisture removed. In the second part, mass & energy conservations principle have been used to analyze components of VARS to cool drinking water of Dilla University from 37.8oC to 16oC within 16 hrs. In the first part, it is assumed that 500 kg of different agricultural products are dried in the cabinet of same dryer. The results show that each of the crops requires different operating parameters due to differences in their thermal properties such as moisture contents, heat capacity, and so on. In the second part, designed VARS operating at evaporation rate of 103.12 kW is capable to cool 66,000 liters of drinking water to the required temperature within 16 hrs each day. It has to be noted that evaporation rate varies with the time needed to cool. If the water to be cooled is within short time, high evaporation rate is then required. Based on the results obtained, it is clear that geothermal energy at Gedeo and Gujji Zones can be utilized for dryer and VAR systems. Furthermore, cost analysis of VARS shows that application of this system will highly contribute to save money and energy of the country.

Geothermal Energy, One Of The Renewable Energies In The Earth, Have Extensively Been Used Worldwide. Its Applications Falls In To Two Classifications; First, Utilizing Heat Energy In The Source Directly And Second, Indirectly Converting It In To Another Energy Form (Electricity). In Ethiopia, With An Estimated Geothermal Potential Of 4200 ?�? 11000 Mw, Aluto Langano Of Oromia Region Morethan 7.2 Mw Of Electrical Power Is Existing Indirect Application. Besides Bathing And Swimming Which Are Estimated To Consume About 2.2 Mw, There Has Been No Investigation On Direct Geothermal Energy Use In Ethiopia. In This Thesis, With An Objective To Analyze Dryer System And Vapor Absorption Refrigeration System (Vars), The Systems Powered By Geothermal Energy For Thermal Applications Such As Drying Of Agricultural Products And Cooling Of Water, Respectively; Thermodynamic And Mathematical Analyses Of The Systems Are Separately Done. In The First Part, When Ambient Air Is Forced To Flow Across The Bundle Of Tubes, Heat And Mass Transfer Model Is Used To Quantify Amount Of Heat Energy Transferred And Moisture Removed. In The Second Part, Mass & Energy Conservations Principle Have Been Used To Analyze Components Of Vars To Cool Drinking Water Of Dilla University From 37.8oc To 16oc Within 16 Hrs.? In The First Part, It Is Assumed That 500 Kg Of Different Agricultural Products Are Dried In The Cabinet Of Same Dryer. The Results Show That Each Of The Crops Requires Different Operating Parameters Due To Differences In Their Thermal Properties Such As Moisture Contents, Heat Capacity, And So On. In The Second Part, Designed Vars Operating At Evaporation Rate Of 103.12 Kw Is Capable To Cool 66,000 Liters Of Drinking Water To The Required Temperature Within 16 Hrs Each Day. It Has To Be Noted That Evaporation Rate Varies With The Time Needed To Cool. If The Water To Be Cooled Is Within Short Time, High Evaporation Rate Is Then Required. Based On The Results Obtained, It Is Clear That Geothermal Energy At Gedeo And Gujji Zones Can Be Utilized For Dryer And Var Systems. Furthermore, Cost Analysis Of Vars Shows That Application Of This System Will Highly Contribute To Save Money And Energy Of The Country.