Estimation of Energy Savings and CO₂ Reduction from the Use of Regional Renewable Energy for an Air Conditioning System at University

Abstract

The use of renewable energy was considered as likely to be effective in achieving an environmentally friendly campus in the medium and the long term. Kyoto University commenced an experimental project involving the use of regional renewable energy in early 2011. The main aim of this study was to clarify the energy savings and CO₂ reduction achieved in this project by the use of regional renewable energy . Solar heat and the energy from burning wood pellets produced by forest thinning were used as renewable energies in this project. These energies were used as a partial energy source for an air conditioning system in a building in the Uji campus, which is one of the campuses in Kyoto University. From the results, the fossil-derived energy savings and CO₂ reduction were estimated to be 1,729 GJ/yr and 119 t-CO₂/yr, respectively. This implied that a reduction of 53.7% of fossil-derived energy consumption and 55.7% of CO₂ emission could be achieved by modifying the existing air conditioning system. The uncertainty analysis indicated that the results of the estimation ranged widely according to the change in the running load of the air-conditioning equipment. The practical and operational aspect of this project needs to be taken into account through actual monitoring, and further evaluations of other environmental impacts or the cost-benefit performance are needed.