nzeb progress including energy efficient HVAC solutions in Central and North Europe

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1 WS 11: CCHVAC REHVA, 24 May 2016, Aalborg nzeb progress including energy efficient HVAC solutions in Central and North Europe Jarek Kurnitski Professor, Vice-president REHVA Tallinn University of Technology Aalto University

2 REHVA nzeb Task Force TF prepared nzeb technical definition and set of system boundaries for primary energy indicator and RER calculation in 2011 in 2013 it was revised in cooperation with CEN, resulting in REHVA Report No:4 Input to EPB Overarching standard pren ISO/DIS :2015 (expected 2016) TF is following nzeb technical, regulatory and policy progress Latest, ongoing analyses on RE contribution and RER indicator based on data from 8 nzeb office and school buildings across the EU

3 Energy flows to be covered by nzeb definition for EP P calculation Primary energy indicator EP P EP P E A P net Edel, i f del, i Eexp, i fexp, i i A net i For thermal and electrical energy it applies: Delivered exported energy = energy use on site renewable

4 EP and RER calculation needs 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

5 US DOE Site Boundary for ZEB Accounting Launched Sept 15,

6 Screening of energy frames and nzeb in 2013 by REHVA 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 uses 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) RES (on site renewable energy production) is not accounted in all countries or is accounted differently

7 Towards nearly zero energy buildings Indicator Denmark Energy frame 2010 Energy frame 2015 Energy frame 2020 Maximum of primary energy to Primary energy factors Residential buildings (houses, hotels, etc.) Non-residential buildings (offices, schools, institutions and other buildings) /A in kwh/m²a /A in kwh/m²a /A in kwh/m²a /A in kwh/m²a 20 kwh/m²a 25 kwh/m²a Electricity District heating

8 Towards nearly zero energy buildings Estonia Primary energy requirements for 9 building types (apply from Jan 9, 2013) nzeb Low energy Min.req. new Min.req. maj.ren. A B C (cost opt.) D (cost opt.) kwh/(m 2 a) kwh/(m 2 a) kwh/(m 2 a) kwh/(m 2 a) Detached houses Apartment buildings Office buildings nzeb and low energy requirements officially given (not yet mandatory) Primary energy factors: Electricity 2.0 Fossil fuels 1.0 District heat 0.9 Renewable fuels 0.75

9 nzeb requirements summary 4/2015 Primary energy and % of minimum EP requirements are used as nzeb EP indicator in most of countries The range of values varies remarkably from positive energy buildings up to 270 kwh/m 2 /y primary energy: from to 20 kwh/m 2 /y to160 kwh/m 2 /y in residential buildings, but usually targets aim at 45 kwh/m 2 /y or 50 kwh/m 2 /y Values from 25 kwh/m 2 /y to 270 kwh/m 2 /y are reported for nonresidential buildings with higher values given for hospitals. Remarkable differences caused mostly due to different energy uses included, but the methodologies/input data have an effect and evidently there are differences in the ambition level nzeb primary energy values show a reduction by factor of 1.6 in Estonia and by 2 in Denmark compared to current EP minimum requirements of office buildings (reduction of 40-50%)

10 REHVA nzeb TF case study buildings FRA SUI Location Type Data Heating Cooling Renewable Dijon, Free cooling + Office Measured Biofuel PV France chiller Gland, Office Simulated GSHP Boreholes PV Switzerland NL1 Hoofddrop, the Netherlands Office Simulated GSHP GSHP BioCHP+SC FIN Helsinki, Finland Office Simulated District heat Boreholes PV NL2 Haarlem, the Netherlands Primary school Simulated, hourly GSHP GSHP PV+SC SWE1 Stockholm, Sweden Office Simulated, hourly District heat Boreholes Wind SWE2 EST Helsingborg, Sweden Rakvere, Estonia Office Office Measured, hourly Simulated, hourly GSHP Boreholes PV District heat Open wells PV

11 Older nzeb case studies Buildings 1-4 are nzeb office buildings in France, Netherlands, Switzerland and Finland Reported in REHVA Journal (3/2011, 2/2012, 5/2012)

12 nzeb Task Force latest buildings (5-8 in the Table) DSK-II school, Haarlem, the Netherlands Väla Gård office building, Sweden Construction year m 2 Extra nzeb cost 250 /m 2 estimated Construction year m 2 Extra nzeb cost 230 /m 2 estimated General description Energy performance Primary school with zero energy consumption, meaning the total amount of energy used for the building itself on an annual basis is roughly equal to the amount of renewable energy produced on site. Net-zero energy building without accounting small power equipment loads, achieved with large on-site PV, heat pumps and energy wells. Entré Lindhagen office building, Sweden General description Energy performance Skanska office in Helsingborg. A nzeb office building, energy consumption is nearly zero or plus including tenant power over the year. LEED certified Platinum. Net zero energy building (small power equipment loads accounted) or plus energy building w/o small power, achieved with extensive on-site PV, ground source heat pump and boreholes. Rakvere Smart Building Competence Centre office building, Estonia Construction year m 2 Extra nzeb cost 55 /m 2 estimated (w/o wind farm investment) Construction year m 2 Extra nzeb cost /m 2 estimated General description Energy performance Skanska head office, Nordea office nzeb building, energy consumption 55 % less than code requirement, building demonstrates low speed ventilation and Skanska Deep Green Cooling, a ground cooling system without heat pump or chiller. Triple Leed Platinum. For core and shell, for Skanska interior design, for Nordea interior design. Net-zero energy building (small power equipment loads accounted) without accounting district heat, achieved with nearby wind farm, district heating and boreholes. Nearly zero energy building if the share of wind farm is not accounted. General description Energy performance Estonian first nzeb office building, primary energy consumption 60 % less than code requirement, building demonstrates smart building automation systems. Nearly zero energy building (small power equipment loads accounted), achieved with on-site PV, district heating and energy wells.

13 Delivered, on-site and nearby generated, and primary energy FRA SUI NL1 FIN NL2 SWE1 SWE2 EST Heating 10,5 6,0 13,3 38,3 20,5 32,2 10,0 25,0 Cooling 2,4 6,7 3,3 0,3 3,2 1,3 0,5 2,0 Fans & pumps 6,5 8,1 17,5 9,4 11,8 13,2 3,0 9,7 Lighting 3,7 16,3 21,1 12,5 12,5 16,5 12,6 11,3 Appliances 21,2 26,8 19,2 19,3 5,0 16,9 12,6 18,5 On site electricity -15,6-30,9-73,8-7,1-36,5-39,0-19,6 Nearby electricity -47,9 BioCHP fuel 184 Exported heat -50,0 Primary energy Primary energy factors nren ren tot Biofuel District heat Electricity

14 nzeb buildings Mass & built form FIN Compactness Ympäristötalo, and deep span office building, achieved with Finland, 2011, inner courtyards No 1 nzeb covered with office in Finland insulated roofs NL2 DSK-II school, Haarlem, the Netherlands, net-zero building, 2014 SWE1 Entré Lindhagen office building, Sweden, 2014, Triple Leed Platinum SWE2 Väla Gård office building, Sweden, 2013, Net-zero (or Energy Plus w/o small power) EST Rakvere SBCC office building, Estonia, 2014, Estonian first nzeb office Technical solutions (5-8) Functions on North and West façade, where solar load is after school day Large building of m 2 Compact massing, roof slope for PV Compact massing, the building is attached to the existing building Façade design Carefully sized windows, South façade is double skin façade with integrated PV and solar shading Fixed Louvre system on the South façade Automated shading, behind outer single glass of double skin or fixed blinds External automated blinds, carefully sized windows, 1/3 of building has fixed horizontal blinds Double façade with automated solar blinds (W), fix shades (S), HVAC, lighting and controls Low pressure DCV and CAV ventilation, occupancy and photocell controlled dimming Low pressure DCV ventilation, floor cooling and heating, LED lighting Low speed ventilation, occupancy and photocell controlled dimming DCV ventilation, medium-temp. radiator heating, occupancy and photocell controlled dimming CAV and DCV ventilation, occupancy and photocell controlled dimming Energy supply On-site RES and storage District heating Borehole cooling = zero energy cooling, PV system (roof and South façade) + battery storage Two open wells Energy wells, solar for energy storage collector for hot and heat pump water, and PV for heating and cooling District heating Borehole cooling = zero energy cooling, nearby wind farm share Ground source heat pump for heating and cooling District heating, two energy wells for cooling Extensive solar PV system and free cooling from ground source Open energy wells for cooling = zero energy cooling and PV system

15 Helsinki, Environmental Centre Ympäristötalo (Kurnitski REHVA Journal 2/2012)

16 Ympäristötalo, Environment Centre of City of Helsinki, Finland Construction year m 2 Extra nzeb cost /m 2 General description Energy performance Environment Centre building Ympäristötalo shows the best energy performance of an office building ever built in Finland. Total primary energy use of 85 kwh/(m 2 a) including small power loads is expected to comply with future nearly zero energy building requirements not given yet. The building is also highly cost efficient, nzeb related extra construction cost was only of 3 4%. Nearly zero energy building (small power equipment loads accounted) achieved with on-site PV, district heating and boreholes.

17 Key solutions Compact massing Window to wall ratio 23 % South facing double facade with integrated PV (60 kw/570 m 2 providing 17% of electricity use) District heating Air conditioning with balanced ventilation, heat recovery and chilled beams Cooling is 100% free cooling from boreholes: 25 boreholes each 250 m depth 15/20 C cooling water dimensioning for AHUs and chilled beams Jarek Kurnitski

18 Key HVAC-solutions Large mechanical rooms on the top floor and low pressure ductwork Specific fan power of main AHUs kw/(m 3 /s) Heat recovery (wheels) temperature ratio %

19 Integrated ventilation and AC with free cooling Air handling unit TE a) TC TC Supply TE Chilled beam Return Cooling water from boreholes a) Room controller TC TE Room Supply ME TE Thermostat Return District heat substation CAV for cellular and open plan offices, DCV for other rooms Active chilled beams in offices and passive chilled beams for other rooms for 24 h cooling (max cooling need 40 W/m2)

20 Heat recovery from toilets no separated exhausts Separated exhaust fans replaced with a small 0.5 m³/s air handling unit with rotary heat exchanger Supply air to toilets, heat recovery of 80%

21 Room conditioning and lighting Active chilled beams (CAV) in offices Lighting fittings of T5 fluorescent lamps with 7 W/m² installed power Occupancy sensors and photocell controlled dimming used in larger rooms, and occupancy sensors in cellular offices

22 Energy performance Major differences compared to Central Europe: much more heating (almost by factor 10) only slightly less cooling more lighting electricity Net energy Delivered Energy Primary need energy carrier energy kwh/(m 2 a) kwh/(m 2 a) factor, - kwh/(m 2 a) Space and ventilation heating 26,6 32,2 0,7 22,6 Hot water heating 4,7 6,1 0,7 4,3 Cooling 10,6 0,3 1,7 0,5 Fans and pumps 9,4 9,4 1,7 16,0 Lighting 12,5 12,5 1,7 21,3 Appliances (plug loads) 19,3 19,3 1,7 32,7 PV -7,1 1,7-12,0 Total

23 DSK-II school, Haarlem, the Netherlands Construction year m 2 Extra nzeb cost 250 /m 2 estimated General description Energy performance Primary school with zero energy consumption, meaning the total amount of energy used for the building itself on an annual basis is roughly equal to the amount of renewable energy produced on site. Net-zero energy building without accounting small power equipment loads, achieved with large onsite PV, heat pumps and energy wells.

24 Väla Gård office building, Sweden Construction year m 2 Extra nzeb cost 230 /m 2 estimated General description Energy performance Skanska office in Helsingborg. An nzeb office building, energy consumption is nearly zero or plus including tenant power over the year. LEED certified Platinum. Net zero energy building (small power equipment loads accounted) or plus energy building w/o small power, achieved with extensive on-site PV, ground source heat pump and boreholes.

25 Rakvere Smart Building Competence Centre office building, Estonia Construction year m 2 Extra nzeb cost /m 2 estimated General description Energy performance Estonian first nzeb office building, primary energy consumption 60 % less than code requirement, building demonstrates smart building automation systems. Nearly zero energy building (small power equipment loads accounted), achieved with on-site PV, district heating and energy wells.

26 Entré Lindhagen office building, Sweden Construction year m 2 Extra nzeb cost 55 /m 2 estimated (w/o wind farm investment) General description Energy performance Skanska head office, Nordea office nzeb building, energy consumption 55 % less than code requirement, building demonstrates low speed ventilation and Skanska Deep Green Cooling, a ground cooling system without heat pump or chiller. Triple Leed Platinum. For core and shell, for Skanska interior design, for Nordea interior design. Net-zero energy building (small power equipment loads accounted) without accounting district heat, achieved with nearby wind farm, district heating and boreholes. Nearly zero energy building if the share of wind farm is not accounted.

27 Terminal pressure drop ventilation (Gräslund REHVA Journal 3/2011) 1-2 step larger ducts and AHUs No need for silencers and most of dampers extremely simple system CAV, but demand controlled with terminal dampers (meeting rooms etc.) SFP=1,3 kw/(m 3 /s) and heat recovery efficiency of 80%

28 Conventional vs. terminal pressure drop ventilation

29 Key performance specification for nzeb (Virta et al. REHVA GB 16 HVAC in sustainable office buildings) Unit Low energy Nearly zero energy SFP of air handling unit kw/m 3 /s < 2.0 < 1.5 Heat recovery efficiency % > 60 > 80 Demand controlled ventilation meeting rooms all spaces Installed lighting power W/m 2 < 10 < 5 Lighting control time, daylight time, daylight, occupancy U-value of window W/K,m 2 < 1.2 < 1.0 g-value of window < 0.7 adaptable (seasons) Solar shading yes automated Infiltration (q 50 ) m 3 /h,m 2 < 1.5 < 0.6 Share of renewable energy % > 10 >20 Some indicative values for key low and nzeb energy design criteria in cold and temperate climates

30 Technical book on nearly zero energy buildings Springer p. for decision makers, engineers, construction clients etc. Worked examples: calculation of delivered, exported and primary energy, and RES contribution Five case studies of nzeb offices show alternative technical solutions and to draw some general design rules based on completed nzeb Early stages design process and architectural competitions control of design streams in scoping and conceptual design 30