No abstract

The high volume of waste produced by both industry and society is common in almost all cities. For this reason, it is necessary to control the increase in the volume of waste and its implications for the environment. The scenario used in this research is to design a power plant that can be used to control the increase in the volume of waste, namely PLTSa (Waste Power Plant). PLTSa uses organic waste from trash to generate clean, renewable energy, powering communities, and reducing emissions. At the PLTSa, the organic waste is fed into a digester tank, where it is converted into methane by bacteria. The gas is then sent to the waste power plant, which generates 0.9 MW of power. The PLTSa supports the Indonesian government’s plan to increase electricity in the country by 35,000 MW from 2015 to 2019, and for 25% of that electricity to be generated from renewable sources. The government’s plan was in response to a shortage of electricity generation capacity as demand in the country grows. The data analysis method used to analyze the research data is an analysis using the IPCC Inventory software and the LFGcost-Web Landfill Gas Emission Model (LandGEM). Data analysis results in the form of projections of biogas potential and electrical energy will be used to build PLTSa. Waste-to-energy generation is being increasingly looked at as a potential energy diversification strategy, especially in Indonesia and PLTSa (Waste Power Plants) in several cities in Indonesia.

The refrigeration and cooling systems activated by waste heat and renewable energy sources can achieve high energy efficiency. In this paper, a performance investigation and working fluid choice for an ejector refrigeration cycle (ERC) activated by renewable energy source are conducted. In the ejector mathematical model, the mixing process through the ejector constant-area section is supposed to be constant-pressure process. The performance of some selected hydrocarbons, hydrofluoroolefins, hydrofluoroethers, and hydrofluorocarbons refrigerants in the ERC is examined and compared. The behaviour of the ejector is represented by the ejector area ratio (EAR) and entrainment ratio (), whereas the cycle performance is represented by the coefficient of performance (COP). The impacts of some selected operating parameters as the condenser, evaporator, and generator temperatures on the ejector behaviour and cycle performances are also examined. The results show that the best ejector behaviour and cycle performance are achieved with the highest critical temperature dry refrigerant, i.e. cyclopentane under all examined operating conditions. From energy efficiency and environmental issues viewpoints, cyclopentane can be considered the most appropriate refrigerant amongst all examined working fluids. However, additional precautions should be taken against its flammability. The highest COP value, the corresponding ω, and the needed EAR using cyclopentane are 0.81, 1.03, and 17.3, respectively with a condenser temperature of 25 ºC and the typical values for the remaining operating parameters.