Programme for energy efficient schools, phase 2: Energy efficient ventilation in schools and participation in IEA Annex 36

IEA Annex 36: Educational buildings such as kindergartens, schools and universities display many similar design, operation and maintenance features in many countries. The two most noteworthy similarities amongst these building types are the high energy consumption and the necessity for retrofitting many buildings within this sector. However, studies have shown that during retrofit, energy saving measures are only rarely applied, because the decision-makers lack knowledge of investments and the efficiency of potential energy saving measures. The main goal of ECBCS Annex 36 is to provide the educational building decision-makers with sufficient data, information and tools to improve their learning and teaching environments by improving the energy efficiency of their buildings. This is the background for the development of an Energy Concept Adviser (ECA) for energy and financial retrofit measures that is useful during the planning and concept development phases for educational buildings. On the one hand to help the owner to find the most efficient energy saving measures and on the other hand to prevent that exaggerated expectations are raised. The ECA should be applicable during the entire retrofitting phase to ensure that both the calculated energy savings and financial success will be achieved after retrofitting. ECA is a tool that assists educational building decision-makers while the construction project is still in the design phase. This tool will improve new or existing buildings through the identification and calculation of potential energy savings. The ECA includes suggestions of energy systems to use and potential design concepts to be considered during the design phase. During the past six years, data have been gathered from all the 10 participating countries of the Annex 36. This electronic Internet-based tool incorporates an interactive source book of information, which includes design concepts, design advise, design and decision programs, and case studies. The tool has been translated into several languages. Ventilation: Heating and ventilation are the most energy consuming activities in Danish schools. But the quality of the indoor climate in a school and its energy consumption seldom correlate. Many schools do have a bad indoor climate and yet a high energy consumption. The purpose of this study is to identify ventilation systems for schools that will contribute to the up-holding of a good indoor climate at a minimal energy consumption. A further purpose is to demonstrate this by investigations in schools where the identified systems are being used. Based on visits and interviews with maintenance staff at approximately 20 schools, it was possible to identify seven promising ventilation systems for use in schools. The systems comprised three types of natural ventilation, windows with automated open-close function, fan assisted system with inlet air preheated in ducts in the ground, stack assisted systems with preheating of inlet air in dual-function convectors. Further-more the following types of balanced mechanical ventilation with efficient heat exchangers were included: mixing ventilation, displacement ventilation, displacement ventilation and presence controlled cut-off dampers for each classroom, classroom units with easily accessed on/off function. The school environment and expectations among students, parents and staff may imply limitations and directions on which systems that may provide the best indoor climate. By using one of the above principles and some of their combinations and avoiding other pitfalls in school design, energy savings of 30-50 % compared with average energy consumption may be achieved