Contract: EIE/07/069/SI Duration: October 2007 – March 2010Version: January 14, 2010 The effects of passive heating and cooling on the energy performance of buildings – CEN - calculation - procedures Anna Staudt and Hans Erhorn Fraunhofer Institute for Building Physics, Germany CENSE

slide 2 Outline The EU CENSE project General aspects of –Passive heating –Passive cooling Structural Measures Consideration of passive heating and cooling in the calculation of the CEN-standard EN ISO –Calculation of heat transfer –Calculation of solar heat gains –Unconditioned sunspaces –Opaque elements with transparent insulation

slide 3 The EU CENSE project (Oct March 2010) Aim of the project: To accelerate adoption and improved effectiveness of the EPBD related CEN- standards in the EU Member States These standards were successively published in the years and are being implemented or planned to be implemented in many EU Member States. However, the full implementation is not a trivial task Main project activities: A.To widely communicate role, status and content of these standards; to provide guidance on the implementation B.To collect comments and good practice examples from Member States aiming to remove obstacles C.To prepare recommendations to CEN for a “second generation” of standards on the integrated energy performance of buildings

slide 4 Brief introduction A brief introduction to the CENSE project and the CEN-EPBD standards is provided in a separate presentation:

slide 5 More information More information and downloads: Disclaimer: CENSE has received funding from the Community’s Intelligent Energy Europe programme under the contract EIE/07/069/SI The content of this presentation reflects the authors view. The author(s) and the European Commission are not liable for any use that may be made of the information contained therein. Moreover, because this is an interim result of the project: any conclusions are only preliminary and may change in the course of the project based on further feedback from the contributors, additional collected information and/or increased insight.

slide 6 General aspects of passive heating Solar energy – the base of passive heating –Solar heating ≠ Passive heating, when solar panels and mech- anical systems are involved –Passive solar heating = Direct heat gain of solar radiation Features of passive heating –Maximising solar heat gain –Minimising heat losses Schematic illustration of direct solar heat gain in an atrium with a glazed roof

slide 7 General aspects of passive cooling Features of passive cooling –Minimizing solar heat gain –Removing unwanted heat Principles –Thermal protection –Air tightness –Use of technologies cooling buildings without fossil energy consumption Thermo-active ceilings – Cold water flowing through the red coloured pipe serves as passive cooling

slide 8 Structural Measures Orientating the main facade southwards (see figure) Aiming at compactness Improving the building’s air tightness Improving the quality of the building’s envelope Avoiding thermal bridges (see figure) Increasing the building’s thermal mass Adapting the distribution of the rooms Effective planning and installation of ventilation devices

slide 9 EN ISO 13790: Calculation of heat transfer Heat transfer by transmission –Driven by the difference between internal and external temperature –Expressed by the overall transmission heat transfer coefficient –Influenceable by the envelope’s area, its thermal transmittance (U-value) and thermal bridges (see figures on the right) Heat transfer by ventilation –Driven by the difference between internal temperature and that of the supply air –Expressed by the overall ventilation heat transfer coefficient –Influenceable by the airflow rate

slide 10 EN ISO 13790: Calculation of solar heat gains Two main types of heat flow –Solar gains through building elements –Thermal radiation to the sky (mostly insignificant) –Overall heat flow = Solar gains - Thermal radiation Solar gains –Opaque elements - Indirect gains mostly insignificant –Glazed elements - Direct gains Influenceable by Product properties: g-value, U-value, frame area fraction Size and orientation Shading devices

slide 11 EN ISO 13790: Unconditioned sun spaces Two types of solar heat gains entering the conditioned space (see adjacent figure) –Direct solar gains through partition wall –Indirect gains from the heated sunspace –Solar heat gains = Direct gains + Indirect gains Calculation method accounts for positive and negative effects during heating and cooling season Simplifications possible (national level) –Conservative approximation treating the sunspace as any unconditioned adjacent space –Improved by simplified method with adjustment factor

slide 12 EN ISO 13790: Opaque elements with transparent insulations Developed to collect solar energy Positive in heating season, negative when cooling Transparent characteristic irrelevant regarding heat transfer by transmission

slide 13 More information On the website, several information papers are presented, the following being on the same topic or strongly related: On CEN standards related to calculation of energy use for heating and cooling : –P95: The different CEN-approaches for calculating the energy use for heating and cooling (Dynamic and quasi-steady-state method, holistic and simple approach) –P92: Information paper on EN ISO standard on energy use for heating and cooling: EN ISO (Energy performance of Buildings – Energy use for space heating and cooling) On key CEN standards to support the EPBD : –P87: Information paper on "How to integrate the CEN-EPBD standards in national building regulations?” –P88: Information paper on "Energy performance of buildings - Overall energy use and definition of energy ratings - Calculated energy rating”

slide 14 More information More information and downloads: Disclaimer: CENSE has received funding from the Community’s Intelligent Energy Europe programme under the contract EIE/07/069/SI The content of this presentation reflects the authors view. The author(s) and the European Commission are not liable for any use that may be made of the information contained therein. Moreover, because this is an interim result of the project: any conclusions are only preliminary and may change in the course of the project based on further feedback from the contributors, additional collected information and/or increased insight.