Space heating emission systems EN 15316-2.1: Emission and control Bjarne W. Olesen International Centre for Indoor Environment and Energy Technical University of Denmark bwo@byg.dtu.dk This presentation will explain the content of the standard

Outline The EU CENSE project Scope of the Standard Heat emission systems German method French method Example This is the outline of the presentation, which also include a short description of the CENSE project

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 The CENSE project is active since 2007. All activities are related to the EPBD-related CEN-standards, where EN15251-2.1 is one of them

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

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/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. Which you can easily access at the CENSE home page

Use of EN15316-2.1 The calculation method is used for the following applications: Calculation of the additional energy losses in the heat emission system; Optimisation of the energy performance of a planned heat emission system, by applying the method to several possible options; Assessing the effect of possible energy conservation measures on an existing heat emission system, by calculating the energy requirements with and without the energy conservation measure implemented. The standard can be used for different applications

Scope of EN15316-2.1 Standardise the required inputs, the outputs and the approach used in the calculation method, in order to achieve a common European calculation method. The energy performance may be assessed either in terms of the heat emission system efficiency or in terms of the increased space temperatures due to heat emission system inefficiencies. The methods are based on the analysis of the following characteristics of a space heating emission system, including its control: non-uniform space temperature distribution; emitters embedded in the building structure; control accuracy of the indoor temperature. The standard include two different approaches

Scope of EN15316-2.1 The energy required by the emission system is calculated separately for thermal energy and electrical energy in order to determine the final energy, and subsequently the corresponding primary energy is calculated. The calculation factors for conversion of energy requirements to primary energy shall be decided at a national level. The thermal energy and electrical energy (auxiliary) is calculated seperately

Energy performance of heat emission systems Calculation concept and building-system boundaries for heating EN15316-1 Input to the calculation is the net energy demand of the building and output is the required energy delivered by the distribution system

Heat energy losses of heat emission They are calculated as: Qem,ls = Q em,str + Q em,emb + Q em,ctr [J] (1) where: Qem,str heat loss due to non-uniform temperature distribution in Joule (J); Qem,emb heat loss due to emitter position (e.g. embedded) in Joule (J); Qem,ctr heat loss due to control of indoor temperature in Joule (J). Non-uniform temperature distribution in a space, emitter position and the efficiency of the room control will be taken into account

Method using efficiencies of the emission system Qem is the additional loss of the heat emission (time period), in J QH is the net heating energy (time period) (EN ISO 13790), in J; fhydr is the factor for the hydraulic balancing. fint is the factor for intermittent operation (intermittent operation is to be understood as a time-dependent option for temperature reduction for each individual room space); fradiant is the factor for the radiation effect (only relevant for radiant heating systems); ηem is the total efficiency level for the heat emission in the room space This method is using efficiencies and based on a method used in German national standards

Total efficiency level ηem where ηstr is the partial efficiency level for a vertical air temperature profile; ηctr is the partial efficiency level for room temperature control; ηemb is the partial efficiency level for specific losses from the external components (embedded systems). Total efficiency where input values can be found in annexes

Emission factors Default values for the different efficiencies and factors can be found in an informative annex to the standard. Some of these values are based on real data from experiments and/or computer simulations, while others are based on a consensus Factor for intermittent operation fint : Radiator = 0.98 Floor heating = 0.97 Factor for radiation effect: frad = 1.0 Other factors like intermittent operation (night set-back etc. ) and radiation effect. The radiant effect is mainly taken into account in industrial premises with radiant heating systems

Factors for hydraulic balancing Benefits will be given depending on the level of hydraulic balancing

The table show an example of input values for efficiency

The table show an example of input values for efficiency

Examples Radiator external wall; over-temperature 42.5 K; P-controller (2 K) ηstr = (ηstr1 + ηstr2 )/2 = (0.93 + 0.95)/2 = 0.94 ηctr = 0.93 ηemb = 1 ηem = 1/(4 – (0.94 + 0.93 + 1)) = 0.88 Floor heating - wet system (water); two-step controller; floor heating with minimum insulation ηstr = 1.0 ηemb = (ηemb1 + ηemb2 )/2= (0.93 + 0.95)/2 = 0.94 ηem = 1/(4 – (1.0 + 0.93 + 0.94)) = 0.88 Oen example of calculated total efficiency for a radiator and a floor heating system

Single family house House with either radiators or floor heating used in the following example

Net Energy for the house EN ISO 13790 Net Energy-House Building 20 40 60 80 100 120 140 160 180 Venice Brussels Stockholm kWh/m2 DHW Heating Calculation of building net energy (demand) according to EN ISO 13790

Heat losses in the heat emission system Example of calculation of the additional heat losses for different combinations of heat emitters and control method

Floor heating extra insulation Heat losses in the heat emission system Residential ΔT ηstr1 ηstr2 ηemb ηctr ηstr ηem Stockholm Qem Brussels Venice Qh = 141,85 Qh = 87,55 Qh = 66,42 kWh/m² Radiators (boiler) 70/55/20 P(2K) 42,5 0,93 0,95 1 0,94 0,88 18,4 11,4 8,6 P(1K) 0,90 15,6 9,6 7,3 PI 0,97 0,92 12,8 7,9 6,0 Radiators (boiler) 55/45/20 P (2K) 30 0,89 17,0 10,5 8,0 P (1K) 0,91 14,2 8,8 6,6 11,3 7,0 5,3 Radiators (Heat Pump) 50/35/20 22,5 0,96 0,955 16,3 10,1 7,6 13,5 8,3 6,3 10,6 5,0   ηemb1 ηemb2 Floor heating P-control 35/28 PI-control Floor heating extra insulation 0,99 No downwards loss 9,9 6,1 4,6 7,1 4,4 3,3 Example of calculation of the additional heat losses for different combinations of heat emitters and control method. The last three columns show the heat losses in kWh/m2 depending on the energy demand (net-energy) in three locations

Method using equivalent increase in internal temperature The equivalent internal temperature, θint,inc taking into account the emitter, is calculated by: where: θint,ini initial internal temperature (°C); Δθstr spatial and vertical variation of temperature; Δ θctr control variation. Input values for different emission systems and controls can be found in the annex. The alternative method also called the French method

Method using equivalent increase in internal temperature The influence of an equivalent increase in internal temperature due to losses from the heat emission system may be calculated in two different ways: 1. By multiplying the calculated building heat demand, QH, with a factor based on the ratio between the equivalent increase in internal temperature, qint,inc, and the average temperature difference for the heating season between the indoor and outdoor temperatures for the space: Qem = QH · ( θint,inc / (int,inc - e,avg) ) [J] 2. By recalculation of the building heat energy requirements, according to EN ISO 13790, using the equivalent increased internal temperature as the set point temperature of the conditioned zone. This second approach leads to better accuracy. Method using equivalent increase in internal temperature

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/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.