1. Gerhard ZWEIFEL HSLU / Switzerland gerhard.zweifel@hslu.ch
Ventilation for buildings - Calculation of room temperatures and of load and energy for buildings with room conditioning systems EN 15243
Gerhard ZWEIFEL
HSLU / Switzerland

2. Outline The EU CENSE project Scope of the Standard
Calculation method-classes
General calculation scheme
HVAC systems overview
Important technical features
Verification
Informative annexes
This is the outline of the presentation, which also includes a short description of the CENSE project

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 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
The CENSE project is active since All activities are related to the EPBD-related CEN-standards, where EN15243 is one of them

4. Brief introduction
A brief introduction to the CENSE project and the CEN-EPBD standards is provided in a separate presentation:
Several documents are available from this project

5. More information More information and downloads: www.iee-cense.eu
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.
Which you can easily access at the CENSE home page

6. Scope of the standard
Covers system related aspects for buildings heating, cooling, humidification and/or dehumidification needs
For the ventilation reference to EN 15241and EN 15242
Based on results from EN ISO calculations of building energy demand
For temperature and load calculation reference to EN ISO and EN 15255
Key issue: possible to use any calculation method
especially including hourly simulations
as long as general requirements are fulfilled
Main driving force: variety of systems in the HVAC domain is very large
no general method is able to cover all types of systems
The standard has a quite large scope including non EPBD related design issues. It adresses buildings which need not only heating, but also cooling and/or humidification/dehumidification. It cevers all system related aspects of these buildings, but references other standards where appropriate. It does not impose a specific calculation method.
It also includes the latent load and energy calculation, since this is nowhere else covered.

7. Calculation method - classes
Type BhSh
Possible to take into account hourly interactions between building behavior and system behavior
Example: VAV system
Type BmSh
When system behavior is not dependent on building behavior
System behavior calculated on hourly values before building calculations
Type BmSm and BhSm
System behavior calculated by averaged monthly, seasonal or annual values
Using statistical analysis based on hourly calculation for typical climates, configurations etc.
Commonly used category: based on the frequency distribution of hourly outdoor air temperature and/or humidity
Combined with hourly or monthly / seasonal building calculations
BhSh or BmSh
SYSTEM
LAT
CALCU­
ION
Hourly
Monthly seasonal annual
BUILDING
BhSh
BhSm
CALCULATION
Monthly seasonal
BmSh
BmSm
Several categories of calculation methods for buildings and systems and their combinations are defined

8. General calculation scheme
In a general calculation scheme, the basic requirements for the calculation, i.e. the processes which it has to cover, are illustrated: losses and auxiliary energy needs at different stages.

9. HVAC system overview CODE SYSTEM NAME
DOES NOT ALWAYS INCLUDE HEATING PROVISION AND MAY BE USED WITH SEPARATE HEATING SYSTEM (INCLUDING ROOM HEATERS WHICH MAY BE WITHIN TERMINALS)
DOES NOT INCLUDE INTEGRAL PROVISION OF VENTILATION AND MAY BE USED WITH SEPARATE (COOLED) VENTILATION SYSTEM A
All-air systems A1
Single duct system (including multi-zone) A2
Dual duct system A3
Single duct, Terminal reheat A4
Constant Volume (with separate heating)  A5
Variable Air Volume (with separate heating) B
Water-based systems B1
Fan coil system, 2-pipe B2
Fan coil system, 3-pipe B3
Fan coil system, 4-pipe B4
Etc….
Since system calculations depend on the system types and the variety of the systems is large, an overview of systems is given. The table in the standard is much longer, only a part is shown here.

10. Important technical features
The important technical features influencing the energy conspumtion of systems are related to the system types. Only a part of the very extensive table in the standard is shown here. This is used to check if a calculation method covers all the required features of a system type (see verification step 1 below)

11. Verification Key requirements Two step verification approach proposed
Credibility:
mechanisms technically sound and results plausible
Discrimination:
rating should be better for systems and buildings clearly more energy-efficient.
Repeatability:
Different users should get essentially the same results for the same building
Transparency:
Straightforward to check data used and execution of the procedure
Two step verification approach proposed
The standard gives general requirements on a verification process for calculation methods.

12. Verification steps Step 1: Define required characteristics
check that the method appears to provide them
Step 2: Verification of calculation accuracy
Reference to several techniques for verifying calculation methods (table)
Application decided on a national basis
If verification technique used -> results obtained to be stated
HVAC system area: only few validation tests from research projects are ready to use for application in standards available
still a lot more research needed
Two main steps for a verification are proposed. Step 1 is a check whether all elevant aspects of a system are covered in a calculation method. Step 2 adresses the calculation accuracy, but there is still lack of available validation tests.

13. Informative annexes Reference to the Energy Diagnosis Reference (EDR)
Dutch methodology to verify performance of calculation procedures
still under development
systematic approach to verification of calculation methods
referring to different validation tools and standards
Example methods given for many specific aspects
Impossible at this time to define single common method due to the variety of approaches in use in the different countries
Often building regulations refer to National standards, impossible for those countries to change
One or two more generations of standard revisions needed to get to a closer harmonization.
This standard is the first step in this direction.
There is a large number of mostly informative annexes in the standard. For the calculation of specific system parts like losses and auxiliary energy demand of chilled water distribution and generation, emission losses, auxiliary demand for heat rejection systems etc. example methods from national standards are given.

14. More information More information and downloads: www.iee-cense.eu
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.