Furthermore, the optimization of insulation thicknesses and solar energy systems for 5 m3 biogas reactor were carried out for two different cities for three different climatic zones in Turkey. In this study, solar heated biogas plants were reviewed. One of the methods is to use solar energy to increase the reactor temperature. In regions with extreme temperature variations, for instance in Turkey, the biogas plant should be built with heating system. Therefore, biogas plants without heating system work only in warmer regions for the whole year. Temperature is an important factor that may affect the performance of anaerobic digestion.
Diurnal thermal efficiencies (ηcol24) of 22% have been measured, but values of 39% have been identified as achievable in the longer-term development of presented ICSSWH. Annulus thermal diode heat transfer coefficients of around (Ufr) 35 W/m²K in forward mode and 2 W/m²K in reverse mode have been demonstrated. The importance of augmenting heat transfer across the annulus cavity has been demonstrated with improvement of the cold-start daily collection efficiency from around (ηcol) of 20% (no HTF), to > 55% when the annulus is evacuated to remove non-condensable gases and form a liquid–vapour phase change thermal diode. A balance between performance and physical/operational considerations is necessary to ensure that new and practical design solutions (in materials, fabrication and assembly) can be formulated to improve the performance of the ICSSWHs within the limits of commercial reality. The energy performance evaluation and characterisation of different prototype designs under solar simulated experimental conditions has been conducted and the subsequent parametric analysis presented. This paper introduces the design evolution of new horizontal cylindrical ICSSWH prototypes developed at Ulster University that use novel, patented double vessel, thermal diode features (to enhance heat retention during non-collection periods) achieved by incorporating a liquid–vapour phase change material (PCM) with a very low pressure annular cavity. However, during non-collection periods they are affected by higher heat loss characteristics when compared to standard solar collector systems.
The results showed that under a range of operating conditions the proposed system has a potential to degrade various feedstocks at a faster rate resulting in improvements in yield for different operating conditions.Įxisting Integrated Collector Storage Solar Water Heaters (ICSSWHs) are typically simple and low-cost devices that combine heat collection and storage functions in one unified vessel. The effect on the acidification process was also investigated by monitoring the batch pH, COD and volatile fatty acid concentration. An experimental programme determined the operational characteristics of the SAAD design covering the aspects of solar heating and its influence on batch AD process. The proposed system is based upon a conceptual Solar Accelerator Anaerobic Digester (SAAD) design developed at the University of Ulster and TERI’s Enhanced Acidification and Methanation (TEAM) developed by The Energy and Resources Institute (TERI), India. In this paper a new hybrid system is proposed. These issues can be addressed by developing small-scale locally applied systems/processes that can be improved by increasing the temperature of the biomass slurry to enhance the process rate. The wide scale application of anaerobic digestion (AD) technology has been limited in colder climate regions as these systems can be adversely affected by low ambient temperatures, leading to a cumbersome digestion of the waste and longer hydraulic retention time resulting in reduced biogas yield.
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