The effects of passive heating and cooling on the energy performance of buildings CEN calculation pr

1
The effects of passive heating and cooling on the
energy performance of buildings CEN -
calculation - proceduresAnna Staudt and Hans
Erhornanna.staudt_at_ibp.fraunhofer.de,
hans.erhorn_at_ibp.fraunhofer.de Fraunhofer
Institute for Building Physics, Germany

• CENSE

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 13790
• Calculation of heat transfer
• Calculation of solar heat gains
• Unconditioned sunspaces
• Opaque elements with transparent insulation

3
The EU CENSE project (Oct. 2007 - 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 2007-2008 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
• To widely communicate role, status and content of
  these standards to provide guidance on the
  implementation
• To collect comments and good practice examples
  from Member States aiming to remove obstacles
• To prepare recommendations to CEN for a second
  generation of standards on the integrated energy
  performance of buildings

4
Brief introduction

• A brief introduction to the CENSE project and the
  CEN-EPBD standards is provided in a separate
  presentation

5
More information

• More information and downloads www.iee-cense.eu

Disclaimer CENSE has received funding from the
Communitys Intelligent Energy Europe programme
under the contract EIE/07/069/SI2.466698. 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.
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
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

Thermoactive ceilings Cold water flowing
through the red coloured pipe serves as passive
cooling
8
Structural Measures

• Orientating the main facade southwards
  (see figure)
• Aiming at compactness
• Improving the buildings air tightness
• Improving the quality of the buildings envelope
• Avoiding thermal bridges (see figure)
• Increasing the buildings thermal mass
• Adapting the distribution of the rooms
• Effective planning and installation of
  ventilation devices

9
EN ISO 13790Calculation 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 envelopes 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

10
EN ISO 13790Calculation 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

11
EN ISO 13790Unconditioned 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

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

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 13790
  (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
•  

14
More information

• More information and downloads www.iee-cense.eu

Disclaimer CENSE has received funding from the
Communitys Intelligent Energy Europe programme
under the contract EIE/07/069/SI2.466698. 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.