Thermodynamic Analysis of Integrated Renewable Energy Systems for Sustainable Building Operation

Abstract

Increasing demands for energy, depleting hydrocarbon reserves, and accelerated climate change drive the need to look for alternative sources of energy. The residential housing sector is one of the main consumers of electrical power worldwide. This thesis aims to contribute to future conservation strategies by focusing on the feasibility and analysis of the integration of renewable energy systems, namely solar and wind power, with cooling and storage equipment, into tri-generation systems. These systems are to provide uninterrupted electrical power, heat and air-conditioning to residential units (villas) in the U.A.E., thus ensuring sustainable, grid-independent operation of the villas. Individual sub-systems are first modeled, verified and analyzed quantitatively and qualitatively through energetic and exergetic analyses respectively, after which three integrated system configurations are also analyzed and present worth analysis is conducted to determine which integrated system is most economical. It must be noted that results presented in this thesis cannot be generalized to all systems as they are for specific operating conditions and for the meteorological conditions of the chosen site in the U.A.E. From the results it can be seen that the integrated PV/T-WT [hybrid photovoltaic / thermal - wind turbine] system performs best during March when wind speeds are highest, the integrated PTSC-TEAS [parabolic trough solar collector - triple effect absorption] system performs better than the PTSC-DEAS [double effect absorption] system for daytime cooling, and the highest energetic and exergetic COPs, 1.77 and 1.7 respectively, are recorded for the combined PTSC-TEAS system during July when average energetic efficiency for the combined PV/T-CGVCS [clathrate generation vapor compression] system is also seen to be highest. The CGVCS is found to be a better thermal storage system than the HTS, its highest COP is obtained for a mass ratio of 2.5 and a maximum mass of 1980.2 kgs of clathrate is required for daily nighttime cooling during August. Lastly, the most feasible overall integrated option studied allows the villas to be completely independent of the grid, has maximum energetic and exergetic efficiencies of 0.38 and 0.201, and offers savings of AED 168,657 over the lifetime of the integrated system. The methods used and the results presented shall prove useful for researchers and decision-makers looking to investigate sustainable building operation options in hot and humid climates.