Browsing by Author "Sirimanna, MPG"

Now showing 1 - 8 of 8

item: Article-Abstract
Estimation of heat exchange across multi-facade roof structures for residential buildings
Sirimanna, MPG; Attalage, RA; Perera, KKCK
Roofs of residential buildings play a crucial role in the context of building heat gains and thermal comfort, since they are exposed to a significant portion of insolation during the day. Therefore, it is important to develop a generalized model to evaluate thermal performance of roof structures under local conditions. This modelling becomes complex due to the dynamic nature of the parameters and various configurations, orientations of the roof surfaces in 3-D space. To address this issue a numerical approach was used to determine view factors of roof surfaces of a generic configuration. Consequently, a thermal model was developed to represent roof structures with four roof surfaces and a ceiling. Model is capable of incorporating insolation on roof surfaces, environmental conditions, roof configuration and materials and obtaining thermal responses of roof surfaces. A computational tool was finally developed based on the model. In this paper, the developed model and the roof thermal responses which were obtained with the aid of computational tool for several roof materials under Sri Lankan environmental conditions are presented and discussed.
item: Thesis-Abstract
Heat gains to building interiors through roofs : a study based on selected configurations in Sri Lanka
(7/21/2012) Sirimanna, MPG; Attalage, RA; Perera, KKCK
Roofs of residential buildings play a crucial role in the context of building heat gains and thermal comfort, since they are exposed to a significant portion of insolation during the day. Therefore, it is important to develop a generalized model to evaluate thermal performance of roof structures under local conditions. This modeling becomes complex due to the dynamic nature of the parameters and various configurations, orientations of the roof surfaces in 3-D space. To address this issue a numerical approach was used to determine view factors of roof surfaces of a generic configuration. Consequently, a thermal model was developed to represent roof structures with four roof surfaces and a ceiling. Model is capable of incorporating insolation on roof surfaces, environmental conditions, roof configuration and materials and obtaining thermal responses of roof surfaces. A computational tool was finally developed based on the model. In order to validate the computational tool, an experimental setup was build and readings were recorded for several days. Same system was simulated using the computational tool and the results were compared. Furthermore, a commercial software and the developed computational tool were used to simulate a selected case and the results were compared with each other.
item: Article-Full-text
A model for analyzing the thermal performance of roof configurations with flat inclined surfaces
(Elsevier, 2016) Sirimanna, MPG; Attalage, RA
tThe development of a thermal model, followed by a generalized computational tool that analyses thermalperformance of roofs with four inclined surfaces and a ceiling by considering dynamic environmentaland operating conditions, changes of roof geometry and materials is presented here. Roof elements areanalyzed based on finite-volume method with implicit formulation. View factors of roof enclosures arecalculated numerically. Experimental results, obtained for six actual building roofs under tropical climaticconditions of Sri Lanka, indicated that the thermal model is capable of replicating the actual temperatureprofiles with an average accuracy of 1.1◦C. Ceiling temperature of common roofs were found to be 10◦Cabove the ambient temperature, which could even rise up to15◦C in hot days. The model was successfullyused to compare roofs and quantify the thermal effects of different parameters. For instance, changes ingeometrical parameters led ceiling temperature to change by 5◦C, highlighting the importance of roofgeometry. Out of the widely used three roofing materials in Sri Lanka, clay tile roofing has showed thebest thermal performance. Compared to clay tiles, asbestos and steel roofing can have a maximum ceilingtemperature rise of 4◦C and 6◦C, respectively.
item: Conference-Abstract
Multi objective optimization and multi criterion decision making in expanding existing standalone energy systems combing renewable energy sources
Perera, ATD; Sirimanna, MPG; Attalage, RA; Perera, KKCK; Dassanayake, VPC
Hybrid Energy Systems (HESs) are becoming popular for standalone applications due to price volatility of fossil fuel resources and global concern on GHG emission. Expansion of an existing standalone Internal Combustion Generator (ICG) system while incorporating renewable energy sources is taken in to discussion in this work which converts ICG systems into a HES. In order to achieve this, a standalone HES consisting of wind turbines, Spy panels, batter bank, ICG and bi-directional converters is mathematically modeled, simulated and optimized considering power supply reliability, Levelized Energy Cost (LEC) and Renewable Energy Capacity (REC). Obtained Pareto fronts were analyzed and simple multi-criterion decision making technique is used to come up with the final system design.
item: Conference-Extended-Abstract
Refrigerated three-wheeler truck
(2009) Sandamali, RC; Senevirathne, NGKSN; Sirimanna, MPG; Fernando, MARV
The mobile fish sellers in Sri Lanka used bicycles, motor bicycles and three wheelers to distribute fish. Refrigerated three-wheeler truck was developed targeting mobile food sellers. A prototype was fabricated which consists of an Electrolux vapour absorption system fitted to a specially designed cool box to suit commonly used three-wheelers. The waste heat in exhaust gas of vehicle is used as the power source. The heat available is sufficient to cater for around 140W unit.
item: Conference-Full-text
A techno-economic analysis for an integrated solar PV/T system with thermal and electrical storage – case study
(2015-08-03) Athukorala, AUCD; Jayasuriya, WJA; Ragulageethan, S; Sirimanna, MPG; Attalage, RA; Perera, ATD
A hybrid photovoltaic/thermal (PV/T) system is having the capability to convert solar energy to both electricity and thermal energy simultaneously and these systems can use to accomplish the energy demand of buildings. Performance analysis of such systems becomes essential to design PV/T systems matching with the operating conditions. It is essential to extend the energy flow analysis used in this regard considering economic limitations especially for urban applications. In this study a practical method to accomplish the energy demand of a building from a PV/T system is proposed and evaluated through a thermo-economic model. The performance of the PV/T collector is analyzed under different operating conditions in Sri Lanka. The responses of energy storage and local grid according to demand variations of the building are evaluated considering the economic aspects. Life cycle cost of the PV/T system is computed to assess the economic viability of harnessing energy from solar energy. Furthermore, the capability of deploying PVT technique and the potential to harvest solar energy in Sri Lanka is evaluated through conducting case studies for different locations.
item: Conference-Abstract
A techno-economic analysis for an integrated solar PV/T system with thermal and electrical storage — Case study
Athukorala, AUCD; Jayasuriya, WJA; Ragulageethan, S; Sirimanna, MPG; Attalage, RA; Perera, ATD
A hybrid photovoltaic/thermal (PV/T) system is having the capability to convert solar energy to both electricity and thermal energy simultaneously and these systems can use to accomplish the energy demand of buildings. Performance analysis of such systems becomes essential to design PV/T systems matching with the operating conditions. It is essential to extend the energy flow analysis used in this regard considering economic limitations especially for urban applications. In this study a practical method to accomplish the energy demand of a building from a PV/T system is proposed and evaluated through a thermo-economic model. The performance of the PV/T collector is analyzed under different operating conditions in Sri Lanka. The responses of energy storage and local grid according to demand variations of the building are evaluated considering the economic aspects. Life cycle cost of the PV/T system is computed to assess the economic viability of harnessing energy from solar energy. Furthermore, the capability of deploying PVT technique and the potential to harvest solar energy in Sri Lanka is evaluated through conducting case studies for different locations.
item: Conference-Abstract
A Techno-economic analysis for an integrated solar PV/T system with thermal and electrical storage – case studyt
Athukorala, AUCD; Jayasuriya, WJA; Ragulageethan, S; Sirimanna, MPG; Attalage, RA; Perera, ATD
A hybrid photovoltaic/thermal (PV/T) system is having the capability to convert solar energy to both electricity and thermal energy simultaneously and these systems can use to accomplish the energy demand of buildings. Performance analysis of such systems becomes essential to design PV/T systems matching with the operating conditions. It is essential to extend the energy flow analysis used in this regard considering economic limitations especially for urban applications. In this study a practical method to accomplish the energy demand of a building from a PV/T system is proposed and evaluated through a thermo-economic model. The performance of the PV/T collector is analyzed under different operating conditions in Sri Lanka. The responses of energy storage and local grid according to demand variations of the building are evaluated considering the economic aspects. Life cycle cost of the PV/T system is computed to assess the economic viability of harnessing energy from solar energy. Furthermore, the capability of deploying PVT technique and the potential to harvest solar energy in Sri Lanka is evaluated through conducting case studies for different locations.