Contract: EIE/07/069/SI Duration: October 2007 – March 2010Version: July 7, 2009 Calculation of the integrated energy performance of buildings EN 15316: Heating systems in buildings Method for calculation of system energy requirements and system efficiencies Heating system operating conditions and multiple generator operation Theo Thijssen TNO Built environment and geosciences The Netherlands

slide 2 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 3 Brief introduction A brief introduction to the CENSE project and the CEN-EPBD standards is provided in a separate presentation:

slide 4 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.

FITTING INTO THE CALCULATION SCHEME slide 5 EN EN HEATING COOLING VENTILATION DHW LIGHTING EN EN EN EN EN EN EN EN XX EN EN EN EN SERVICES BUILDING NEEDS EMISSION &DISTRIBUTION LOAD DISPATCHING OVERALL PERFORMANCE GENERATION Operating conditions

Flow and return temperature of heat transporting medium Flow rate of heat transporting medium Heat demand On-off cycling / load control Generator room temperature Source conditions

Calculation of heating system temperatures Calculation procedure (EN chapter 8) Calculate emitter average temperature Take into account distribution circuits effects Maximum flow / average return at distribution collectors level Take into account generation circuits effects slide 7

Total effect slide 8 TEMPERATURE LEVELS CAN BE QUITE DIFFERENT AT EMITTERS, DISTRIBUTION HEADERS AND GENERATION LEVEL

Detailed information on water temperature calculation The following slides include some examples about the detailed calculation of water temperature all along a heating system slide 9 SKIP DETAILED INFORMATION ABOUT WATER TEMPERATURE CALCULATION SKIP DETAILED INFORMATION ABOUT WATER TEMPERATURE CALCULATION

Emitters temperatures, example 1 slide 10 Typical hydraulic connection for constant flow rate variable temperature operation (heating curve) Temperature and flow rate pattern

Emitters temperatures, example 2 slide 11 Typical hydraulic connection for variable flow rate variable temperature operation (thermostatic valves) Temperature and flow rate pattern, Including the effect of a 70 °C max flow temperature setting

Emitters temperatures, example 3 slide 12 Typical hydraulic connection for intermittent flow rate constant temperature operation (room thermostat) Temperature and flow rate pattern, This operation mode can be combined with a heating curve

Emitters temperatures, example 4 slide 13 Typical hydraulic connection for intermittent fan constant flow rate and temperature operation (fan-coil) Temperature and flow rate pattern,

Mixing valve distribution circuit Emitter connection through a mixing valve. Typical for central control or for lower temperature emitters. Distribution network temperature is the same as emitters temperature Flow rate before the mixing valve is less than in the emitters.. slide 14 Nominal 1 80/60 Nominal 1 80/60

By-pass distribution circuit Emitter connection with a by-pass Typical for the connection of HVAC hot heat exchanger or single pipe circuits. Distribution network losses increase when the emitter power is reduced. Flow rate in the network is greater than required by the emitters causing higher auxiliary energy needs. slide 15 Nominal 1 80/60 Nominal 1 80/60

Boiler connections slide 16 DIRECT CONNECTION INDEPENDENT FLOW RATE CONNECTION

slide 17 INDEPENDENT FLOW RATE CONNECTION Higher flow rate in the boiler  return temperature to the boiler is higher than distribution return temperature Such operating condition would prevent condensation INDEPENDENT FLOW RATE CONNECTION Higher flow rate in the boiler  return temperature to the boiler is higher than distribution return temperature Such operating condition would prevent condensation 34,8 kW

Operating conditions generator flow and return temperature flow return Generator efficiency depends on return and flow temperature Some generators will show greater dependency than others

Operating conditions demand Generator must fit the building Large generator in small home = low part loads = decreased efficiency

Operating conditions on-off cycling / load control T flow time on/off modulating

Operating conditions Generator room temperature Heated spaceUnheated space 10 °C20 °C Generator Losses Recovered Unrecovered

Operating conditions source conditions Source temperature (°C) COP

Actual full-load performance curves slide 23 Hot sink (water) temperature °C

Multi generator operation Fraction of demand per generator Operation mode Load distribution Temperature levels Configuration of the installation

Multiple generators demand fraction 0 % 100 % ?? % Gen 2Gen 1 η Gen 1 η Gen 2 Two generators with different efficiencies Total system effiency depends on distribution of the heat demand:

Multiple generators operation mode & load distribution Outside temperature Cumulative hours (a) (b) (c)

Multiple generators temperature levels Gen. 1 flow return Gen. 2 Gen. 1 flow return Gen. 2 Serial Parallel Different configurations resulting in different temperature levels for both generators

Multiple generators configuration of installation Space heating Boilers Circulation loop Hot water Circulation loop = increased losses Temperature level circulation loop depends on function: Only space heating Also sanitary hot water Higher temperature level = decrease of generator performance

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.