Sustainable Thermal Energy Generation at Universities by Using Loquat Seeds as Biofuel

Abstract

Global energy consumption has increased the emission of greenhouse gases (GHG), these being the main cause of global warming. Within renewable energies, bioenergy has undergone a great development in recent years. This is due to its carbon neutral balance and the fact that bioenergy can be obtained from a range of biomass resources, including residues from forestry, agricultural or livestock industries, the rapid rotation of forest plantations, the development of energy crops, organic matter from urban solid waste, and other sources of organic waste from agro-food industries. Processing factories that use loquats to make products such as liqueurs and jams generate large amounts of waste mainly in the form of skin and stones or seeds. These wastes are disposed of and sent to landfills without making environmentally sustainable use of them. The University of Almeria Sports Centre is made up of indoor spaces in which different sports can be practiced: sports centre pavilion (central court and two lateral courts), rocodrome, fitness room, cycle inner room, and indoor swimming pool. At present, the indoor swimming pool of the University of Almeria (UAL) has two fuel oil boilers, with a nominal power of 267 kW. The main objective of this study is to propose an energetic analysis to determine, on the one hand, the energetic properties of the loquat seed and, on the other hand, to evaluate its suitability to be used as a solid biofuel to feed the boilers of the heated swimming pool of the University of Almeria (Spain), highlighting the significant energy and environmental savings obtained. Results show that the higher calorific value of loquat seed (17.205 MJ/kg), is like other industrial wastes such as wheat straw, or pistachio shell, which demonstrates the energy potential of this residual biomass. In addition, the change of the fuel oil boiler to a biomass (loquat seed) boiler in the UAL’s indoor swimming pool means a reduction of 147,973.8 kg of CO2 in emissions into the atmosphere and an annual saving of 35,739.5 €, which means a saving of 72.78% with respect to the previous fuel oil installation. A sensitivity analysis shows that fuel cost of base case is the variable with the most sensitivity changing the initial cost and net present value (NPV).