Dick van Dijk
MS Applied Physics
Senior advisor TNO
Leeghwaterstraat 44, NL 2628 CA Delft, The
Team leader set of EPB standards related to
Msc Civil Engineering
TNO, Heat Transfer and Fluid Dynamics; team
Co-team leader EPB standards related to CEN/TC
Linda Hoes - van Oeffelen
MSc Built Environment (Building physics)
TNO, Heat Transfer and Fluid Dynamics; team
Co-team leader EPB standards related to CEN/TC
EN ISO 52016-1 presents a coherent set of calculation methods
at different levels of detail, for the (sensible) energy needs for the space
heating and cooling and (latent) energy needs (de)humidification of a building
and/or internal temperatures and heating and/or cooling loads, including the
influence from technical buildings systems, control aspects and boundary
conditions where relevant for the calculation. EN ISO 52016-1 is
currently in a final drafting stage.
Keywords: energy performance of buildings, EPB, EPB
regulations, heating need, cooling need, thermal balance, indoor temperature,
heating load, cooling load.
CEN Mandate M/480  a comprehensive series of European (CEN) and
international (CEN & ISO) standards is at an advanced stage of development.
The series is called the "set of EPB standards" and aims at the international
harmonization of the methodology for the assessment of the overall and partial energy
performances of buildings. The first issue of the 2015 REHVA journal focused on
the EPB standards. Article  contained a broad overview of the subset of EPB
standards on the energy use and the thermal performance of buildings and
article provides further information on one of this subset, namely the standard
EN ISO 52016-1, which is being developed in ISO/TC 163/SC 2/WG 15.
EN ISO 52016-1 , accompanied by the
technical report CEN ISO/TR ISO 52016-2 , contains a (new)
simplified hourly calculation method and a monthly calculation method for the
calculation of the (sensible) energy need for heating and cooling and the
(latent) energy need for (de)humidification. This standard cancels and replaces
EN ISO 13790:2008.
Additional applications covered in the hourly
method of EN ISO 52016-1,
with specifically adapted boundary conditions,
simplifications and input data, are:
of internal temperatures, e.g. under summer conditions without cooling or
winter conditions without heating;
of design heating or cooling load.
The calculations are done per so called "thermal
zone", a concept that is introduced in EN ISO 52000-1
. It is up to national or regional choice to calculate different zones separately
or thermally coupled. The main reasons for choosing for uncoupled zones is the
lack of reliable input data on the heat exchange properties (thermal
transmission, air circulation and ventilation) between zones plus the impact of
variable user behaviour.
The effect of specific system properties can also
be taken into account, such as the maximum heating or cooling power and the
impact of specific system control provisions. This leads to system-specific
loads and needs.
monthly calculation method
The hourly and the monthly method in EN ISO
52016-1 are closely linked: they use as much as possible the same input data
and assumptions. And the hourly method produces as additional output the key
monthly quantities needed to generate parameters for the monthly calculation
method. This means that a number of (nationally) representative cases can be
run with the hourly method and from the key monthly quantities the monthly
correlation factors can be derived (see ).
This article focuses mainly on the hourly
With the hourly calculation method, the
thermal balance of the building or building zone is made up at an hourly time
interval. The method is a specific application of the generic method provided
in EN ISO 52017-1 .
The hourly method in EN ISO 52016-1 is more
advanced than the simplified hourly method given in EN ISO 13790:2008. The
main difference is that the building elements are not aggregated to a few
lumped parameters, but kept separate in the model. This is illustrated in Figure 1.
a) Improved hourly method (and similar for monthly method) in EN ISO
b) Simplified hourly method in EN ISO 13790:2008
Figure 1. Improved hourly method in EN ISO 52016-1
(a) compared to simplified method in EN ISO 13790:2008 (b).
This makes the method more transparent and
more widely usable, e.g. because:
there is no worry about how to
combine e.g. the heat flow through the roof and through the ground floor, with
their very different environment conditions (ground temperature and ground
inertia, solar radiation on the roof);
the thermal mass of the building
or building zone can be specified per building element and there is no need for
an arbitrary lumping into one overall thermal capacity for the building or
the mean indoor surface
temperature (mean radiant temperature) can be clearly identified and distinct
from the indoor air temperature.
Only the standard writers will have to
introduce extra data: hourly operation schedules and weather data. On the other
hand, the standard writers don't need to prepare tables with pre-calculated
factors (on operation of blinds, effect of solar shading, etc.).
The main goal of the hourly calculation method
compared to the monthly method is to be able to take into account the influence
of hourly and daily variations in weather, operation (solar blinds,
thermostats, heating and cooling needs, occupation, heat accumulation, etc.)
and their dynamic interactions for heating and cooling. This limited goal
enables to avoid the need for extra input to be supplied by the user compared
to the monthly calculation method (with national/regional options for slightly
more detailed data).
The hourly climatic data are given in EN ISO 52010-1
and the hourly and daily patterns of the conditions of use (operating
schedules) are given in the relevant other EPB standards.
Unambiguous but flexible
All EPB standards follow specific rules to
ensure overall consistency, unambiguity and transparency.
All EPB standards also provide a certain
flexibility with regard
to the methods, the required input dataand references to other EPB standards,
by the introduction of a normative template in Annex A and Annex B with informative default choices. Also EN ISO 52016-1 offers different options, at various levels, that are open for choice at
national or regional level. This enables to take into account differences due
to national or regional climatic conditions, regulatory context and policies,
building tradition and status of technology (current, for new buildings; and
past, for assessing existing buildings). This is particularly important because
of the application in the context of building regulations, e.g. for energy
performance (EP) rating, EP certificates and EP requirements. See also the
parallel article on EN ISO 52003.
with the common template for all EPB standards, a spreadsheet has been prepared
for demonstration and validation. This spreadsheet shows an overview of all input
hourly and monthly
calculation procedures and an overview of all output variables.
In the previous REHVA Special on the EPB
standards  the many links of EN ISO 52016-1 with other EPB
standards were introduced. Special attention in this respect has been paid to testing
the link with the procedures to calculate the thermal transmission through the ground
floor, taking into account the inertia of the ground. These procedures
are given in EN ISO 13370 , for monthly or seasonal calculation
methods, but also for hourly calculation methods (based on dynamic simulations
as described in ). Because of the dynamic, time dependent interactions,
these procedures were also integrated in the spreadsheet for EN ISO 52016-1.
With minor adaptations in EN ISO 13370 compared to the current
published version, the calculation procedures of EN ISO 13370 have
been proven to work as intended as input for the monthly and hourly building
calculations of EN ISO 52016-1.
The hourly calculation procedures on the thermal
zone level have been validated by using relevant cases from the so called
BESTESTseries. The BESTEST cases are well established since
decades (several IEA ECBCS annexes and IEA SHC tasks), widely used worldwide,
well described (e.g. ASHRAE 140, ) and regularly extended with additional
cases. The successive series of test cases are also very powerful as diagnostic
tool. Renowned institutes participate in the set-up of the test cases. The
calculation results of several renowned software tools are available for
comparison. Examples of input data for BESTEST cases are available for several
building simulation tools and within different ICT environments.
The "drawback" of the BESTEST series
is that there is no single reference "true" result and no acceptance
criteria. The hourly calculation procedures in EN ISO 52016-1 are
fully described ('prescribed'). This means that the results of the test cases
should be the same for all users, if the same input data and boundary
conditions are used. So there is no need to validate application of
EN ISO 52016-1. As a consequence, the test cases and the results are
presented in the standard, not to validate
the method, but to enable a verification
by others (e.g. software developers).
Of course, as part of the development of this standard, it is interesting to compare the
results with the results available from the renowned software tools; some
results are presented below.
The same BESTEST cases are also used for the
validation of the procedures in EN ISO 52010-1, to calculate the
distribution of solar radiation on a non-horizontal plane based on measured
hourly solar radiation data on a horizontal surface. These results are
presented in a parallel article. The results of that calculation, the hourly
irradiation at vertical planes of different orientation, are input for the
validation tests of EN ISO 52016-1.
Figure 2 shows the geometry of the test room.
Figure 2. BESTESTS: Geometry of the test
The following cases were selected:
Table 1. The selected BESTEST cases with case
heating and cooling
heating and cooling
No heating and cooling (free float)
Note that the selected BESTEST test cases do
not include for instance:
Ground floor heat transfer coupled
Thermal coupling between two or
The effect of thermal bridges.
Sunspace or other thermally
Solar shading by external
obstacles (distant, remote or from own building elements).
Complex control patterns (e.g.
weekend interruption of mechanical ventilation and/or heating and cooling
and/or solar shading, etc.; night time ventilation as free cooling, heat
recovery by pass, …)
The ground floor heat transfer was tested
separately, as described above. In the selected BESTEST cases the heat transfer
is decoupled from the ground. The other features may be tested analytically or
require dynamic links with system related calculation standards.
The composite Figure 3 provides
the main results of the Case 600 and 600FF. Note that the climate is Denver
(Col., USA), with quite cold but sunny winter and warm and sunny summer.
Figure 3. BESTESTS: Main results for
Case 600 and 600FF, EN ISO 52016-1 compared with the available 9
It also has to be taken into consideration
that not each software program whose results are available for the comparison
use nowadays state-of-the-art algorithms (in that sense these are not reference
results). This is because these base cases of the BESTEST series were created
and tested many years ago.
technical report CEN
ISO/TR ISO 52010-2 provides
background information, explanation (including examples) and justification
(including more validation cases).
EN ISO 52016-1,
currently in a final drafting stage, presents a coherent set of
calculation methods at different levels of detail, for the (sensible) energy needs
for the space heating and cooling and (latent) energy needs for (de-)humidification
of a building and/or internal temperatures and heating and/or cooling loads,
including the influence from technical buildings systems, control aspects and
boundary conditions where relevant for the calculation.
possible at national or regional level to accommodate the specific national or
hourly calculation method is more powerful than the simplified method in its
predecessor EN ISO 13790:2008. It still requires no more input data
from the user than the monthly method. The method has been successfully
validated using relevant BESTEST cases.
information will become available in the accompanying technical report,
CEN ISO/TR 52016-2 .
would like to acknowledge the contributions of the other experts in the team
that is responsible for the preparation of EN ISO 52016: Dirk Van Orshoven (DVO, Belgium), who significantly contributed to the updating of the
monthly method, Gerhard Zweifel, who developed the application for
design cooling load calculations and contributed to the setup of the latent
heat calculation (including link with the EPB ventilation and cooling system
standards under CEN/TC 156), Matjaž Zupan (Planta, Slovenia) for preparing calculation
examples and running tests and José L. Molina (Universidad de Sevilla, Spain) and Francisco José Sánchez de la Flor(Universidad de Cádiz, Spain) who developed the solar shading
calculation procedures for EN ISO 52010 and EN ISO 52016.
would also like to acknowledge, for their valuable input and comments, all the
active experts in the ISO and CEN working groups to which the preparation of
these standards has been assigned, as well as all the commenters who have
 Mandate M480, Mandate to CEN, CENELEC and
ETSI for the elaboration and adoption of standards for a methodology
calculating the integrated energy performance of buildings and promoting the
energy efficiency of buildings, in accordance with the terms set in the recast
of the Directive on the energy performance of buildings (2010/31/EU) of 14th
 D. van Dijk, M. Spiekman, D. Van Orshoven,
W. Plokker, Subset of EPB standards on the energy use and the thermal
performance of buildings and building elements The REHVA European HVAC Journal,
Volume: 52 Issue: 1 January 2015.
 EN ISO 52016-1, Energy performance of
buildings — Calculation of the energy needs for heating and cooling, internal
temperatures and heating and cooling load in a building or building zone — Part
1: Calculation procedures (in preparation; title subject to revision;
submission of FDIS to final ballot expected in 2016).
 CEN ISO/TR 52016-2, Energy performance of buildings — Calculation
of the energy needs for heating and cooling, internal temperatures and heating
and cooling load in a building or building zone —Part 2: Explanation and
justification of ISO 52016-1 and ISO 5207-1 (in preparation; title subject
to revision; submission to Committee Approval expected in 2016).
ISO 52017-1, Energy performance of buildings — Calculation of the energy needs
for heating and cooling, internal temperatures and heating and cooling load in
a building or building zone -- Part 1: Generic calculation procedures (in
preparation; title subject to revision; submission of FDIS to final ballot
expected in 2016).
ISO 52000-1, Energy performance of buildings — Overarching EPB assessment –
Part 1: General framework and procedures (in preparation; submission of FDIS to
final ballot expected in 2016).
ISO 13370, Thermal performance of buildings — Heat transfer via the ground —
Calculation methods (in preparation; submission of FDIS to final ballot
expected in 2016).
ISO/TR 52019-2, Energy performance of buildings (EPB) — Hygrothermal
performance of building components and building elements — Part 2: Explanation
and justification (in preparation; submission to Committee Approval expected in
standard 140, Standard Method of Test for the Evaluation of Building Energy
Analysis Computer Programs, 2014.