John Gelegenis

Determination of fixed expenses in central heating costs allocation: An arising issue of dispute

Purpose – The purpose of this paper is to investigate the reduction in efficiency of central heating systems of multi-family buildings when independent heating capability is offered to each apartment, to access the impact of the applied heating cost allocation (HCA) on this deterioration and suggest highly cost-effective ways (operation, control strategy, alternative HCA) of overcoming them at minimum cost. Design/methodology/approach – The paper reveals the problem of reduced efficiency in centrally heated multi-family dwellings through two case studies in real buildings, where data-loggers were installed and performance curve analysis was performed, in combination with detailed simulation. Findings – The paper finds that the enforcement of a suitable HCA regulation is a prerequisite to achieving energy savings in centrally heated multi-family dwellings. In addition the effects of dissimilarly heated apartments on the total energy demand and the significance of indirect heating and how these should be ch...

Optimum external wall insulation thickness considering the annual CO2 emissions

Increasing the insulation thickness in residential buildings leads to the reduction of operational CO2 emissions but simultaneously increases the embodied CO2 due to the insulation material. The environmentally optimum insulation thickness exists at a point where the total CO2 emissions are minimum. This work presents the optimum insulation thickness for external walls of different composition and orientation, for both the heating and the cooling period. Three different wall types and insulation materials are being presented. The dynamic thermal behavior of the external walls simulation is based on the heat conduction transfer functions method and using the hourly climatic data available for the city of Athens, Greece. The optimization methodology uses a single objective function approach, combining the simulation of the thermal behavior of external walls with an optimization algorithm. The results indicate that the optimum insulation thickness varies from 11.2 to 23.4 cm and is different for each orientation, wall type, and insulation material. In addition, the total annual CO2 emissions per unit area of the wall can be reduced by 63.2%–72.2%, depending on the insulation material and its position on the wall.

Energy engineering: an emerging discipline

Abstract: This chapter describes the emerging engineering discipline ‘energy engineering’, which is expected to contribute to the development of the sustainable energy supplies required by the global community. First the need to develop energy engineering education is documented, and its historical evolution is reviewed. Then energy engineering education at undergraduate and postgraduate levels are considered separately, and the characteristics of energy engineering syllabuses are identified. Finally, there is a discussion about possible perspectives for energy engineering.