@thesis{thesis,
		author={Astuti  Elly Dwi and Sudirmanto  Sudirmanto},
		title ={Pengaruh nilai kalor batu bara terhadap efisiensi boiler unit 1 PLTU Suralaya},
		year={2020},
		url={http://156.67.221.169/3211/},
		abstract={A boiler is an equipment to convert water into steam by heating the water using coal. Coal is a fossil fuel from remained ancient living things that are still on earth. The longer coal is stored on earth, the higher the temperature. Coal is classified based on its rank such as lignite, bituminous, and sub-bituminous coal which each of them has different heat values. Lignite coal has 3000-4611kcal/kg of heat value, bituminous coal has a heat value of 58333-7777kilocalories/kg while sub-bituminous coal has 4611-5833kcal/kg heat value. The greater the heat value, the higher the efficiency in the boiler. In this thesis, the author calculated the efficiency of the boiler from April to June 2020. In April, the efficiency is 81.069% with a heat value of 4562 kcal/kg, In May, the efficiency is 81.908% with 4952kcal/kg of heat value, whereas in June the efficiency is 81.974% with a heat value of 4669kcal/kg. From the result, it is obtained that the efficiency value affects the heat losses. The more heat losses occur, the lower the efficiency value obtained.}
		}