Building solutions for improving energy efficiency
Pilot Project in Athens Kessariani Arch. Dionysia Triantafyllou, Region of Attica Province of Athens
2nd Junior HIGH SCHOOL of Kessariani The 2nd Junior HIGH SCHOOL of Kessariani, located at the North-East of the centre of Athens and next to the mountain of Imittos, as a part of a school complex next to a highly dense urban area in the Greek capital, has been chosen mainly because of its energy consumption measured, but also because of the difficulties and - or possibilities for retrofitting and improving its energy efficiency. Being a small size public school building, built and managed by the Greek School Building Organisation, and having a typical organisation of two wings of classrooms, with a central corridor in the middle, the building has completely different problems from the 1st TECHNICAL HIGH SCHOOL (EPAL) of Kessariani examined as the 1st pilot project. Therefore, we find that it can give many directions in how to manage with different problems concerning the energy consumption and buildings’ retrofitting, being also an interesting pilot project. The school is located in a typical middle to low incomes urban area of Athens, rather dense, with 6-7 storeys residential buildings. The climate is typical in Athens and the greater Attica region, and it is characterised by mild winters and hot dry summers. Throughout the year, temperatures average at: • summer 32º Celsius • autumn 23º Celsius • winter 12º Celsius and • spring 20º Celsius The particular school is also privileged by the advantage of the neighbouring Kessariani park, which provides good ventilation and fresh air to the entire neighbourhood, keeping temperatures almost 2 degrees lower during the hot summer days. Rainfall is mainly during the winter and
annual rainfall levels are not high. The main energy consumption problems identified at the school were focused on the building’s envelope. Major problems causing energy consumption had to do with heat losses through badly or non-insulated surfaces. External walls and reinforced concrete elements, roof, doors and windows need revision in terms of thermal losses and U values. The wing of classrooms oriented towards the North-west is totally different in terms of solar gains and losses from the one oriented South-east, and this affects definitely the indoor comfort. Energy consumption on lighting is very high. Natural light in most classrooms is either causing glare or is insufficient for covering the depth of the classrooms. There should be a completely different policy in terms of managing openings and shadowing. The building has a good potential for natural ventilation, but the flap widows at the corridors are not used at all for that purpose. The main measures proposed were costevaluated, as low, medium and high cost, and their effectiveness according to the relative cost. In order to be realistic, and taking under consideration the fact of the economic crisis that the country is going through, the measures proposed to be taken are rather the ones that fall under the low or medium cost categories. In the particular school, the measures proposed are the following: a. Insulation of external walls, inclined roofs, flat roof b. Creation of new openings, towards the South, were this is feasible, in order to assure better cross ventilation to as many classrooms as possible. Redesigning of the
-South oriented- big skylight. c. Creation of green roof surfaces. d. Installation of light-shelves at the Northwest façade in order to improve lighting conditions – visual comfort on the inside. e. Installation of shading devices at the windows of the South-east façade, will not only provide shadow during the summer and prevent classrooms from overheating, but also better distribution of natural lighting (and consequently visual comfort) inside the classroom. f. Installation of PV panels at the South-west façade of the building g. Construction of a pergola with deciduous plants, to the South East façade which will provide shadow during the summer months, preventing classrooms from overheating during the summer, allowing at the same time penetration of air and sun in a filtered way. During the winter and rainy days, the students will have the possibility to go outside for their breaks (staying inside is not good because of CO2 concentration and bad ventilation). h. Installation of ceiling fans i. Redesigning the “heated areas” map of the building, by reducing the thermal load as possible. j. Replacement of existing heating system with an autonomous system by wing and by floor, fitted with thermostats k. Integrated management and control l. Possibilities regarding the future of this school building are highly appreciated, given the fact that energy consumption and indoor comfort will be radically improved. Certainly, the best part of this work is the knowledge gained in designing ecological buildings in the future and retrofitting the existing ones.