Energy Systems Engineering

In this study, grape pomace was dried in an infrared film dryer at 40, 45 and 50 °C surface temperatures to investigate the effects of heat transfer mechanism (natural and forced convection) and homogeneous drying on specific energy consumption, drying rate and drying time. Also, energy and exergy efficiencies were calculated. The average specific energy consumption values were calculated as 5.90, 4.49 and 4.07 kWh/kg in natural convection (Group 1) and 11.90, 11.32 and 11.81 kWh/kg in forced convection (Group 2), respectively. The maximum energy efficiency was observed as 54.71% at 45 °C in Group 1. Energy efficiencies at the experiments in Group 1 were found to be nearly 10% higher than Group 2. The maximum exergy efficiency was observed as 38.46% at 50 °C in Group 1, and the average exergy efficiency values for Group 1 and 2 were calculated as 34.84% and 33.76%, respectively. Group 2 experiments provided a faster drying process as expected. However, although forced convection was...

Interest in renewable energy sources is growing when economic values such as air pollution, climate change and external dependency on the environment are considered in the process of depletion of fossil fuels. Despite of energy supply security ensuring thanks to availability of renewable energy resources, they can not respond instantly. Therefore they are used together with non-polluting or electricity sources such as electricity. In this study, the number of planar solar collectors was changed between 2 and 10, and the coverage ratio of the solar energy in the heating system, coefficient of the performance and the performance factor of the system were examined via POLYSUN simulation program.

The current paper proposes a novel multi-generation system, integrated with compound parabolic collectors and a biomass combustor. In addition to analyzing the comprehensive system in a steady state, the feasibility of using nanofluids as heat transfer fluids in the solar cycle and their effect on the overall performance of the system was studied. The multi-generation system is generally designed for generating electricity, cooling, freshwater, drying, hot water, and hydrogen, with the help of six subsystems. These include a double stage refrigeration system, an organic Rankine cycle, a steam Rankine cycle, a dryer, a proton exchange membrane electrolyzer, and a multistage flash distillation system. Two types of nanoparticles (graphene, silver), which have various high-quality properties when used within ethylene glycol, were chosen as absorbing fluids in the solar cycle. The performance parameters of the base case thermodynamic analysis and some of the variable parameters were calc...

Abstract Solar air collectors are integrated into the air source heat pump in order to increase the performance of the heat pump in cold climate regions. The evaporator air is heated by solar air collectors. In this study, two different types of solar air collectors which were textile based solar air collector and flat plate solar air collector were used. The thermal energy stored in the tank during the day was used to heat the room at day and night. The thermal storage tank was heated using three heating systems, textile based solar assisted air source heat pump (TSAHP), flat plate solar assisted air source heat pump (FSAHP) and air source heat pump (ASHP). In this study, energy, exergy and economic analysis of three different heating systems were performed. COP values increased by 32% in TSAHP and 21% in FSAHP compared to ASHP. Addition of solar air collectors to the ASHP heating system has been shown to improve thermal storage tank performance. Total exergy efficiency values were calculated as 14.4%, 13.4% and 11.3%, for TSAHP, FSAHP and ASHP heating systems, respectively. Levelized cost of heating of novel type system (TSAHP) ($/kWh) was 11.8% lower than conventional ASHP.