Global Advanced Research Journal of Engineering, Technology and Innovation (GARJETI) SSN: 2315-5124 December 2014 Vol. 3(9), pp 235-247

Copyright © 2014 Global Advanced Research Journals   

Original Research Articles

Upgrading of Low Temperature Heat with Absorption Heat Transformer for Generating Electricity by Organic Rankine Cycle 

Nattaporn Chaiyat 

School of Renewable Energy, Maejo University, Chiang Mai, Thailand

Corresponding author: benz178tii@hotmail.com 

Accepted 28 November 2014

Abstract 

This study presents a concept to generate electricity from low temperature heat by using an absorption heat transformer (AHT) coupled with an Organic Rankine Cycle (ORC). The prototypes of a 10 kW AHT system and a 20 kW ORC system were tested and evaluated the thermal performances which were used to predict the system performance of the modified system. From experiment, it could be seen that the H2O-LiBr AHT could upgrade the final temperature to be around 90-110oC at coefficient of performance (COP) of 0.44. For the R-245fa ORC system, it could be found that the system efficiency was around 8.5% at supplied water temperature higher than 90oC. From prediction results, it could be shown that a 250 kW AHT system was selected to generate electricity with the 20 kW ORC system. For economic results, saving cost and payback period of the integrated unit based on the electricity cost of Thailand were 5,945.82 USD/y and 15.96 y, respectively. The value of levelized electricity costs (LEC) of the modified system was 0.547 USD/kWh. From the above results, it could be concluded that electricity process by using the AHT and ORC systems to upgrade and transfer heat to power was beneficial in term of energy efficiency, but was deficient in term of economic results. 

Keywords: Absorption heat transformer; Organic Rankin Cycle; Thermal performance; Low temperature heat; Simplified model