CA EPBD III MEETING IN MALMÖ
October 10, 2013
REHVA nZEB
technical definition
– 2013 revision
Jarek Kurnitski
Professor, Vice-president REHVA
Tallinn University of Technology
Aalto University
jarek.kurnitski@ttu.ee
www.nzeb.ee
Federation of European Heating, Ventilation and Air-conditioning Associations
Presentation outline
1. REHVA nZEB technical definition
2. Implementation – some national examples
Federation of European Heating, Ventilation and Air-conditioning Associations
REHVA nZEB definition 2013
• Is intended to help the experts in the Member States in defining the
nearly zero energy buildings in a uniform way – so that local
conditions are taken into account, but the uniform methodology used
• Proposes a technical definition for nZEB buildings following EPBD
recast and Cost-optimal regulation
• Provides energy calculation framework and system boundaries
associated with the definition, prepared in the level of detail to be
suitable for the implementation in national building codes for the
primary energy and renewable energy ratio indicators’ calculation
Federation of European Heating, Ventilation and Air-conditioning Associations
EPBD recast established targets for
cost optimal and nZEB
• EPBD recast (2010/31/EU) requires that energy performance minimum
requirements are to be set with a view to achieving cost optimal levels using
a comparative methodology framework established by the Commission:
- Cost optimal performance level is defined as the energy performance in
terms of primary energy leading to minimum life cycle cost
• EPBD recast established the target of nearly zero energy buildings (nZEB)
for all new buildings (Article 9):
- By 31 Dec 2020, all new buildings are nearly zero energy buildings
- After 31 Dec 2018, public authorities that occupy and own a new building
shall ensure that the building is a nearly zero energy building
http://ec.europa.eu/energy/efficiency/buildings/buildings_en.htm
http://eur-lex.europa.eu/LexUriServ/LexUriServ.do?uri=OJ:L:2012:081:0018:0036:EN:PDF
Federation of European Heating, Ventilation and Air-conditioning Associations
EPBD recast – Nearly zero
energy buildings nZEB
• In the directive ‘nearly zero-energy building’ means a building that has
a very high energy performance. The nearly zero or very low amount
of energy required should be covered to a very significant extent by
energy from renewable sources, including energy from renewable
sources produced on-site or nearby.
 nZEB = very high energy performance + on-site renewables
• Definition of “a very high energy performance“ and “significant extent
of renewables” let for Member States
Federation of European Heating, Ventilation and Air-conditioning Associations
EPBD definition for energy performance
EPBD definitions (article 2):
•
‘energy performance of a building’ means the calculated or measured
amount of energy needed to meet the energy demand associated with a
typical use of the building, which includes, inter alia, energy used for
heating, cooling, ventilation, hot water and lighting
Other services
may or may not
be included in the
rating – included
in REHVA
definition
Federation of European Heating, Ventilation and Air-conditioning Associations
Energy flows to be covered by nZEB
definition for EPP calculation
Primary energy indicator EPP
EP 
EPP 
 i
Anet
E
del ,i
For thermal and electrical energy it applies:
Delivered – exported energy = energy use – on site renewable
Federation of European Heating, Ventilation and Air-conditioning Associations
f del ,i   Eexp,i f exp,i 
i
Anet
Some most debated questions in the
preparation of nZEB definition
• The order of demand reduction and RES measures?
– Equal treatment – may be decided on cost optimal bases (on site
renewable energy is inside the system boundary, i.e. is directly
subtracted from energy use)
– Was confirmed in the EC’s Cost-optimal regulations (No 244/2012).
Quote: “the RES-based active technologies enter into direct
competition with demand-side solutions, which is in line with the
purpose and intention of the cost optimal calculation to identify the
solution that represents the least global costs without discriminating
against or favouring a certain technology.”
• Which primary energy factors are to be used? The development of
national factors:
– EC’s Cost-optimal regulations requires the use of non-renewable
primary energy in the cost optimality assessment
– (in reality, national factors include energy policy, e.g. for renewable
fuels often in between of the total and non-renewable)
Federation of European Heating, Ventilation and Air-conditioning Associations
REHVA nZEB definition 2013
net zero energy building (net ZEB)
Non-renewable primary energy of 0 kWh/(m2 a).
net ZEB has exact
performance level of 0
kWh/(m2 a) primary energy
NOTE A net ZEB is typically a grid connected building with very high energy performance. A net ZEB balances its
primary energy use so that the primary energy feed-in to the grid or other energy network equals to the primary energy
delivered to ZEB from energy networks. Annual balance of 0 kWh/(m 2 a) primary energy use typically leads to the
situation where significant amount of the on-site energy generation will be exchanged with the grid.
nearly zero energy building (nZEB)
Technically and reasonably achievable national energy use of > 0 kWh/(m2 a)
but no more than a national limit value of non-renewable primary energy,
achieved with a combination of best practice energy efficiency measures and
renewable energy technologies which may or may not be cost optimal.
NOTE 1 ‘reasonably achievable’ means by comparison with national energy use benchmarks appropriate to the
activities served by the building, or any other metric that is deemed appropriate by each EU Member State.
NOTE 2. Renewable energy technologies needed in nearly zero energy buildings may or may not be cost-effective,
depending on available national financial incentives.
nZEB depends on national
conditions
Federation of European Heating, Ventilation and Air-conditioning Associations
nZEB def is based on detailed system boundaries
• System boundaries (SB) for energy need, energy use and delivered and exported energy
calculation. The last one may be interpreted as the building site boundary.
• Demand reduction measures can be distinguished from RE solutions in the energy use SB,
not in the delivered/exported energy SB
Federation of European Heating, Ventilation and Air-conditioning Associations
Example – nZEB Office building
• an office building in Paris
• a gas boiler for heating with seasonal efficiency of 90%
• free cooling from boreholes (about 1/3 of the need) is used and the
rest is covered with mechanical cooling
• for borehole cooling, seasonal energy efficiency ratio of 10 is used
and for mechanical cooling 3.5
• Ventilation system with specific fan power of 1.2 kW/(m3/s) will use
5.6 kWh/(m2 a) fan energy
• a solar PV system providing 15.0 kWh/(m2 a), from which 6.0 is
utilized in the building and 9.0 is exported to the grid
Federation of European Heating, Ventilation and Air-conditioning Associations
Example of nZEB office – primary energy
• Electricity use of cooling, ventilation, lighting and appliances is 39.8 kWh/(m2 a)
• Solar electricity of 6.0 kWh/(m2 a) reduces the delivered electricity to 33.8 kWh/(m2 a)
• Net delivered fuel energy (caloric value) is 4.2 kWh/(m2 a) and primary energy is 54 kWh/(m2 a)
Federation of European Heating, Ventilation and Air-conditioning Associations
RER system boundary
New element
in the system
boundary
• Thermal energy from ambient heat exchangers to be accounted (in the
delivered/exported energy calculation calculated with COP)
Federation of European Heating, Ventilation and Air-conditioning Associations
RER Equation
(based on total primary energy)
RERP 
E
i
E
i
ren ,i
   f del ,tot ,i  f del ,nren ,i E del ,i 
i
ren ,i
  E del ,i f del ,tot ,i   Eexp,i f exp,tot ,i 
i
i
where
RERP is the renewable energy ratio based on the total primary energy,
Eren,i is the renewable energy produced on site or nearby for energy carrier i, kWh/a;
fdel,tot,i is the total primary energy factor (-) for the delivered energy carrier i;
fdel,nren,i is the non-renewable primary energy factor (-) for the delivered energy carrier i;
fexp,tot,i is the total primary energy factor (-)of the delivered energy compensated by the exported energy for
energy carrier i;
Edel,i
is the delivered energy on site or nearby for energy carrier i, kWh/a;
Eexp,i is the exported energy on site or nearby for energy carrier i, kWh/a.
•
The renewable energy ratio is calculated relative to all energy use in the
building, in terms of total primary energy
•
Ambient heat sources of heat pumps and free cooling are to be included to
the renewable energy use system boundary
Federation of European Heating, Ventilation and Air-conditioning Associations
RER: Example of nZEB office
• The same input data as in previous example
Federation of European Heating, Ventilation and Air-conditioning Associations
System boundary for nearby RE
•
System boundary for nearby RE plants contractually linked to the
building (a share of the capacity/production can be linked to the building)
•
National legislation needed to allocate new RE capacity to the
building/developement with a long term contract
Federation of European Heating, Ventilation and Air-conditioning Associations
System boundary for multiple buildings
DELIVERED
ENERGY
Electricity
District heat
District cooling
Building n
Fuels
(renewable and
non-renewable)
Building 2
EXPORTED
ENERGY
Electricity
Building 1
SITE ENERGY
CENTRE
Building site boundary = system boundary of delivered and exported energy
Federation of European Heating, Ventilation and Air-conditioning Associations
Heating en.
Cooling en.
Summary: REHVA nZEB 2013
• ZEB, net ZEB, PEB and nZEB definitions
• A set of system boundaries to calculate:
– Energy need
– Energy use
– Delivered and exported energy
– Primary energy
– Renewable energy ratio
– Nearby energy production
– Sites with multiple buildings
• Load matching and grid interactions
• Worked examples
• National low energy and nZEB requirements/targets from
selected countries
Federation of European Heating, Ventilation and Air-conditioning Associations
Implementation – some national
examples
Latest updates of regulation – nZEB under preparation:
• Germany
• Sweden
nZEB definitions:
• Denmark
• Estonia
• Norway
Federation of European Heating, Ventilation and Air-conditioning Associations
Estonia
200
Primary energy, kWh/m2a
Towards nZEB:
• Roadmap of some
countries towards
nearly zero energy
buildings to improve
energy performance
of new buildings
• Many countries have
prepared long term
roadmaps with
detailed targets
• Helps industry to
prepare/commit to
the targets
150
100
50
0
Federation of European Heating, Ventilation and Air-conditioning Associations
2008
2013
2021
nZEB definitions
• European definitions based on EPBD recast:
– REHVA 2013 – REHVA has revised its nZEB technical definition
and set of system boundaries for primary energy indicator and RER
calculation in cooperation with CEN, soon available www.rehva.eu
– CEN is working with overarching EPBD standard prEN 15603:2013,
which will include calculation bases for primary energy and RER
• National definitions – Concerted Action CA EPBD (March 2013
data) has collected detailed information from 19 countries:
– of which six have their national application of the nZEB definition
included in a legal document (Cyprus, Denmark, Estonia, Lithuania,
Slovak Republic and France) – 9 countries Oct 2013 data
– six other countries have their application developed, but not yet
fixed in a legal document
– and the remaining seven countries have documented their current
plans
Federation of European Heating, Ventilation and Air-conditioning Associations
Situation with energy frames
• In most of countries, on site renewable energy production is
subtracted from delivered energy
• Differences in energy frames:
– primary energy not yet used in all countries
– Some countries (Germany, France) use reference building method,
fixed values in other countries
– Both simulation (Estonia, Finland) and monthly methods (Germany,
Denmark) used
• Inclusion of energy flows depends on country:
– Germany/residential – heating energy only (space heating, DHW and heating
of ventilation air)
– Germany/non-residential – cooling and lighting also included (appliances not)
– Denmark – appliances and in residential also lighting not included
– Sweden – appliances and user’s lighting not included (facility lighting incl.)
– Estonia, Finland, Norway – appliances and lighting included (all inclusive)
Federation of European Heating, Ventilation and Air-conditioning Associations
Energy frames, exported energy
• Exported electricity can be taken into account on annual basis
(full utilization), monthly bases (limited to the amount of the
delivered electricity each month and the rest of exported is not
accounted) or is not taken into account
• Full utilization (annual bases):
– Denmark, Estonia, net plus energy program in Germany
• Monthly bases:
– Germany, Sweden? (not decided)
• Not accounted
– Finland, Norway, Italy
• Most of energy frames not yet
ready to support exported energy
Federation of European Heating, Ventilation and Air-conditioning Associations
Development of primary energy
requirements for heating in Germany
Federation of European Heating, Ventilation and Air-conditioning Associations
Latest Swedish energy performance
requirements on delivered energy
Annual delivered energy use for heating, comfort cooling,
domestic hot water provision and other shared services in
the building (kWh/m2)
Climate zone
1 (north Sweden)
2 (middle Sweden)
3 (south Sweden)
Residential buildings with heating systems
other than electric heating
130
110
90
Residential buildings with electric heating
95
75
55
120 +
Commercial and similar premises with
heating systems other than electric heating
110 x (q − 0,35)
95 +
Commercial and similar premises with
electric heating
65 x (q − 0,35)
110 +
90 x (q − 0,35)
75 +
55 x (q − 0,35)
80 +
70 x (q − 0,35)
55 +
45 x (q − 0,35)
• Requirements for delivered energy use from the 1st of Jan 2013
• Previous building codes 2006 and 2009, nZEB definition 2015
Federation of European Heating, Ventilation and Air-conditioning Associations
Towards nearly zero energy buildings
Denmark
Characteristic
values
Maximum of
primary energy to
Residential buildings (houses,
hotels, etc.)
Non-residential buildings
(offices, schools, institutions
and other buildings)
Conversion factors Electricity
District heating
Energy
frame
2010
Energy
frame
2015
52.5 +
1650/A
in
kWh/m²a
71.3 +
1650/A
in
kWh/m²a
2.5
1.0
30 +
20
1000/A kWh/m²a
in
kWh/m²a
41 +
25
1000/A kWh/m²a
in
kWh/m²a
2.5
1.8
0.8
0.6
Federation of European Heating, Ventilation and Air-conditioning Associations
Energy
frame
2020
Towards nearly zero energy buildings
Estonia
Primary energy requirements for 9 building types (apply from Jan 9, 2013)
nZEB
A
kWh/(m2 a)
Low energy
B
kWh/(m2 a)
Min.req. new Min.req. maj.ren.
C (cost opt.)
D (cost opt.)
kWh/(m2 a)
kWh/(m2 a)
Detached houses
50
120
160
210
Apartment buildings
100
120
150
180
Office buildings
100
130
160
210
•
nZEB and low energy requirements officially given (not yet mandatory)
•
Conversion factors:
– Electricity 2.0
– Fossil fuels 1.0
– District heat 0.9
– Renewable fuels 0.75
Federation of European Heating, Ventilation and Air-conditioning Associations
Towards nearly zero energy buildings
Norway
Energy frame [kWh/m²y]
Building Code
TEK07 TEK10 TEK15 - Passive house
Residential
135
(detached house)
Residential
(office)
TEK25
TEK30
nearly
ZEB
Intermediate
Net
ZEB
130
80
120
115
(Heating: 15, Cooling: 0, DHW: 30)
165
150
75*
(apartment block)
Non-residential
TEK20
(Heating: 20, Cooling: 10, DHW: 5)
*
the low value is largely due to improvement in electrical appliances and adoption of demand
controlled lighting and ventilation, on top of envelope improvements. Furthermore, the low amount
of hot water required in offices makes the total energy need lower than for residential units.
•
Requirements for energy need for 13 building types
•
Energy balance is between energy need and delivered energy (generation
not included, HVAC-electricity and cooling included)
•
All inclusive energy frame (appliances, lighting and cooling included)
•
nZEB definition under development
Federation of European Heating, Ventilation and Air-conditioning Associations
How to compare min. requirements?
Detached house (CLIMA 2013 data)
• Recalculation from primary
energy to delivered energy
needed, which can be
compared in all countries
• The figure shows maximum
allowed delivered energy
without household electricity
(i.e. delivered energy to
heating, hot water and
ventilation systems) in each
country for fossil fuel or
electrical heating
Oil or gas boiler
Electrical heating
100
Max delivered energy, kWh/(m2a)
• 150 m2 detached house
considered
• Degree-day correction (base
17°C) to Copenhagen, energy
use for hot water heating 25
kWh/(m2a)
120
80
60
40
20
0
Denmark
Norway
Federation of European Heating, Ventilation and Air-conditioning Associations
Sweden
Estonia
Finland
Apartment and office buildings
with district heating
140
Apartment building
Office building
Max delivered energy, kWh/(m2a)
120
100
80
60
40
20
0
Denmark
•
Norway
Sweden
Estonia
Finland
Maximum allowed delivered energy for heating, hot water and
ventilation systems in apartment buildings and for office buildings
(lighting included) with district heating
Federation of European Heating, Ventilation and Air-conditioning Associations