Proceedings of ECOS 2009 22 nd International Conference on Efficiency, Cost, Optimization Copyright © 2009 by ABCM Simulation and Environmental Impact of Energy Systems August 31 – September 3, 2009, Foz do Iguaçu, Paraná, Brazil PARAMETRIC STUDY AND SEASONAL SIMULATIONS OF A SOLAR POWERED ADSORPTION COOLING SYSTEM Onur Taylan, otaylan@metu.edu.tr Derek K. Baker, dbaker@metu.edu.tr Department of Mechanical Engineering, Middle East Technical University, 06531 Ankara, TURKEY Bilgin Kaftanoğlu, bilgink@atilim.edu.tr Department of Manufacturing Engineering, Atilim University, 06836 Incek, Ankara, TURKEY Abstract. Models of solar-thermal powered adsorption cooling systems with and without heat recovery developed in TRNSYS and results from steady-periodic and seasonal simulations are presented. A normalized model is presented and used to process the seasonal TRNSYS results to investigate the coincidence between the solar-supplied cooling power and cooling load as the relative sizes of the cooling system and storage are varied. The normalized model yields a seasonal solar fraction and seasonal loss fraction (the excess solar-supplied cooling lost to the environment due to insufficient storage). Simulations were run for a zeolite-water adsorbent-refrigerant pair. Hourly weather data for Antalya, Turkey, were used for the transient simulations. Basic trends in performance were investigated as the following parameters were varied: system type (with or without heat recovery); incident radiation; maximum and minimum bed temperatures; condensation temperature; difference between condensation and minimum bed temperatures (bed excess temperature); bed’s dead mass; collector type (flat plate vs. evacuated tube); cooling tower type (wet vs. dry); cooling system size; and, storage size. Results for the conditions explored include the following. Steady-periodic simulations show that the system’s COP decreases with decreases in radiation and increases with minimum bed and condensation temperatures. Increasing the excess bed temperature increases the system’s COP. Systems with an evacuated tube collector and wet cooling tower give higher system COP’s than systems with a flat plate collector and dry cooling tower. The increase in system’s COP due to decreasing the bed’s dead mass and adding heat recovery is quantified. The solar fraction increases and the loss fraction decreases with increases in storage capacity, and both fractions decrease with increases in maximum bed temperature. The required evacuated tube collector area is smaller than the flat plate collector area while the required mass of adsorbent is independent of collector and adsorption cycle types. Keywords: adsorption, air conditioning, cooling, simulation, solar 1. INTRODUCTION Turkey is a developing country and like other developing countries has a rapidly growing electricity demand. In 2007, approximately 81% of Turkey’s electricity demand was met by thermal sources (coal, lignite, fuel oil, LPG and natural gas) of which 61.2% was natural gas. Most of this natural gas was imported, which leads to energy security concerns (TEĐAŞ 2007). The remaining 19% of Turkey’s electricity demand was met by hydro, geothermal, wind, and other resources. According to Turkish Electricity Transmission Corporation’s projections (TEĐAŞ 2008), electricity demand will exceed supply in 2014. Therefore, within Turkey there is an acute need for new energy supplies that are domestic and sustainable. One reason for Turkey’s increasing electricity demand is increasing cooling loads, especially on Turkey’s Mediterranean coast where summers are long and hot. The city of Antalya is situated on this coast and electricity shortages are common during the summer due to large air conditioning loads. Antalya also has a large tourism industry with many luxury resorts. These resorts typically use conventional vapor-compression air conditioners to meet their cooling demand and are assumed to be one of the major reasons for the electricity shortages. The motivation for this research is to investigate technologies that could reduce the electricity demand for cooling in Antalya. Thermal powered cooling systems such as solar-thermal powered adsorption cooling cycles could be used to reduce the electrical load associated with cooling. Like other Turkish Mediterranean cities, Antalya has large solar resources. This study is performed to assess the feasibility of using solar energy to drive thermal powered adsorption cooling systems using synthetic zeolite-water as the adsorbent-refrigerant pair and located in Antalya, Turkey. Synthetic zeolite is chosen as the adsorbent since Turkey has large natural zeolite resources that can be engineered, and water is chosen as the refrigerant since it is environmentally benign. Adsorption cooling is well established but does not have much market penetration. In the literature many reviews of adsorption cycles exist (Dieng and Wang 2001; Meunier 2001; Sumathy et al. 2003). Furthermore, there are several studies on adsorption cycles that investigate the effects of parameters on the system energy performance (Sward et al. 2000; Liu and Leong 2005; Khan et al. 2007). This work builds directly on previous studies (Baker 2008; Baker and Kaftanoğlu 2008) in which thermodynamic models were developed for adsorption cooling cycles with no thermal regeneration and maximum thermal regeneration between two spatially isothermal beds. Specifically, these previously developed adsorption cycle models are integrated with existing solar component models in TRNSYS (The Transient