NZEB in Estonia, new buildings and major renovation

1. NZEB in Estonia, new buildings and major renovation Jarek Kurnitski 22.10.2019

2. Estonian energy performance regulation The energy performance requirement of buildings is based on primary energy use that is the only requirement (since 2008) and therefore allows very flexible design and construction Energy performance requirements are linked with EPC classes (NZEB = A) The NZEB requirements have been in place since 9th of January 2013 but were detailed in Nov 2018

4. Estonian energy performance regulation – latest version/NZEB MKM no 63 regulation 01.01.2019 Minimum requirements for energy performance 2. MKM no 58 regulation 21.01.2019 Methodology for calculating the energy performance of buildings 3. MKM no 36 regulation 21.01.2019 Format and procedure of issuance of energy performance certificates

5. Estonian system boundaries One of the most advanced energy frames with full utilization of on site and nearby renewable energy, but not exported energy Follows REHVA NZEB definition and systemboundaries Lighting&Appliances included in EP-value, i.e. calculated≈measured

6. REHVA system boundaries

7. Example of energy performance calculation (GSHP) Primary energy: EPP = 0.4*0.9 + 40.2*2.0 = 80.8 kWh/(m2 a) (Exported energy is not taken into account)

8. Estonian regulation – EP Compliance assessment • For all buildings except detached houses, energy performance calculation shall be based on dynamic building simulation • There is no official simulation tool, but requirements are specified for commercial simulation tools, which mainly refer to validation according to relevant European, ISO, ASHRAE or CIBSE standards, IEA BESTEST or other equivalent generally accepted method • Dynamic simulation is not required in two cases: • Detached houses may use an alternative compliance assessment method based on simple energy calculator • In the major renovation of residential buildings without cooling, monthly energy calculation methods are accepted • Simulation based energy calculation methodology allows to simulate energy needs and to calculate systems with post-processing, or alternatively the systems may be included in the simulation (heat recovery always needs to be included in the simulation) • There are no limitations for technical systems to be taken into account; generally accepted calculation methods should be used (European standards, etc.) or tabulated values of common systems losses/efficiencies given in the methodology may be used if not calculated in detailed fashion

9. Estonian regulation – Summer thermal comfort • If no coolingis installed, a dynamic temperature simulation in critical rooms isrequired in order to comply with summer temperature requirements (25°C + 100 °Ch in non-residential and 27°C + 150 °Ch in residential buildings during three summer months simulated with TRY) • An exception for detached houses, there the compliance may be alternatively shown with tabulated values for solar shading, window sizes and window airing (4 key performance values) Temperatureexcessover 27 °C

10. Transition to nZEB 01.01.2019 Low energy building is a building that is built with energy efficiency and renewable energy solutions in the technically reasonable fashion and that is not expected to generate on-site electricity from a renewable energy source. 01.01.2020 Nearly zero energy building is a building that is built with energy efficiency and renewable energy solutions in the technically reasonable fashion. NZEB must achieve the low energy building requirement (EPC class B) without on-site electricity generation.

11. General public reaction to nZEB – both negative and positive

12. 2018 updates for the energy performance requirements EPC class A = NZEB, for major renovations EPC class C is required EPC class B is to be achieved without on-site electricity generation New weighting (primary energy) factors: • electricity 2.0; • district heating 0.9; • efficient district heating 0.65; • renewable fuels 0.65; • district cooling 0.4; • efficient district cooling 0.2; • fossil fuels 1.0.

13. 2018 updates for the energy performance requirements Exceptions for nearly zero energy buildings on-site electricity generation (if no space in the roof or shadings limit generation below 70% of optimal) Exported energy is not any more accounted in EP-value On-site RES can serve more than one building/building site – nearby RE generation enabled, but needs to be directly connected to the buildings (cannot be transported via medium/low voltage grid or district heating network)

14. Energy performance requirements – Primary energy EPP “current” means 2013; Final requirements are marked as “New”

15. Energy performance certificates Calculated EPCs and EPCs based on real metered use will become more close – methodology, process and metering updated to provide tools to bridge the gap between calculated and measured EP EPC must be issued before the building permit, but an updated calculated EPC must be issued for the use permit application After 2 years of operation EPC based on metered energy use will be issued

16. Apartment building example Small building and compactness not best possible – relatively high heat losses Reference building used in NZEB requirement testing Cost optimal solutions: External wall U=0.14, roof U=0.12, external floor U=0.14, windows U=0.9 (overall), building leakage rate q50=1.5, heat recovery ventilation with single dwelling units having electrical reheating coils and rotary heat exchangers of 80% temperature ratio

17. Apartment building example – energy use Calculated without PV to check the EPC class B requirement – achieved with district heating and ground source heat pump For heat pumps 80% power sizing is used DHW, lighting and appliances are regulated values To achieve NZEB/class A=105, 15 kWh/(m2 a) PV production is needed with DH (18 with GSHP) at default 55% usage rate in the building [16/2.0/0.55=15 kWh/(m2 a)]

18. Nearly zero energy Apartment building constructions Construction examples from an existing apartment building “redesigned” to nZEB level External wall thickness remained same - λinsulation 0.33 → 0.24 W/mK External wall Roof External floor

19. Typical ventilation systems in dwellings Single-family house New apartment building Heat recovery decentralized ventilation, rotary heat exchangers often used Electrical reheating coils in residential buildings (preheating coils avoided)

20. Residential buildings are divided into nine Energy Performance Certificate classes • Class A+ marks the highest energy efficiency and class H the lowest level • Energy performance requirement for the new apartment buildings is in the range of class A…B • Energy performance requirement for major renovation corresponds to class C • Existing apartment buildings locate mainly in the EPC classes F or G Energy performance classification Deep Renovation Concepts

21. Estonian nZEB converted to Germany German NZEB/EPC includes delivered energy of HVAC Lighting, appliances and primary energy factors are not considered – major differences compared to Estonia Estonian apartment building example results roughly: • German A+ with ground source heat pump • German A with air to water heat pump • German B with district heating or gas boiler Many limitations: • Climate differences, domestic hot water use and also many other differences in input data and methodology are significant and are not adequately taken into account in this comparison → All variants likely to be German NZEB, but only the district heating and GSHP variant Estonian NZEB → German regulation is not ready (or too easy) for heat pumps

22. Estonian renovation concepts Centralized supply and exhaust ventilation system with heat recovery, ductwork installation in the insulation layer and radiator heating Single room ventilation units not accepted Depending on the building, may achieve EPC class C or B

23. Estonian renovation concepts Ventilation radiators with exhaust heat pump heat recovery EPC class C (less effective heat recovery because of electricity use of the heat pump)

24. CONCLUSIONS Effective district heating roughly equals with GSHP with Estonian new primary energy factors EPC class B requirement has to be achieved without on-site electricity generation Typically PV-production is needed for NZEB (except in single-family houses smaller than 220 m2) Exported energy is not any more accounted in EP value Nearby RES is enabled, as RE system may serve more than one building (mostly for area development) Requirements are very challenging for gas boiler