Click to edit Master title styleEstonian cost optimal calculation and implementation in the code

14.03.2013 CA-EPBD III Madrid

Jarek KurnitskiProfessor, Tallinn University of TechnologyVice-president REHVAjarek.kurnitski@ttu.eewww.nzeb.ee

Presentation outline

Estonian cost optimal calculations:• conducted as a financial calculation in 2011

Implementation into building code:• cost optimal energy performance minimum reqs. for new

buildings and major renovations apply from Jan 9, 2013

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 (must for Cost Optimal)

• Differences in energy frames:

– primary energy not yet used in all countries (must for Cost Optimal)

– 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) (must for Cost Optimal?):

– 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

Estonian Cost Optimal: Seven step systematic procedure (Kurnitski et al. Energy and Buildings 43 (2011)

1. selection of the reference building/buildings2. definition of construction concepts based on building

envelope optimization for fixed specific heat loss levels (from business as usual construction to highly insulated building envelope in 4 steps)

3. specification of building technical systems 4. energy calculations for specified construction concepts5. post processing of energy results to calculate delivered,

exported and primary energy 6. economic calculations for construction cost and net present

value of operating cost7. sensitivity analyses (discount rate, escalation of energy

prices and other parameters)

• All this steps are independent, iterative approach not needed for residential buildings, because of the specific heat loss method used

• Worked well for residential, non-residential buildings less predictable

Reference buildings – proposed by the society of Estonian architects, 3 out of 6 buildings shown

9.11.2011

Jarek Kurnitski

Pre-optimized building envelopeThe specific heat loss coefficient includes transmission and infiltration losses through the building envelope and is calculated per heated net floor area:

Construction concepts

DH 0.42 “Nearly zero”

DH 0.58

DH 0.76

DH 0.96 “BAU”

Specific heat loss coefficient H/A, W/m2K

0.42 0.58 0.76 0.96

External wall 170 m2

20cm LECA block, plaster + 35cm EPS-insulation U 0.1 W/m2K

20cm LECA block, plaster + 25cm EPS-insulation U 0.14 W/m2K

20cm LECA block, plaster + 20cm EPS-insulation U 0.17 W/m2K

20cm LECA block, plaster + 15cm EPS-insulation U 0.23 W/m2K

Roof 93 m2

Wooden beams, metal sheet, 80cm min.wool insulation, concrete slab U 0.06 W/m2K

Wooden beams, metal sheet, 50cm min.wool insulation, concrete slab U 0.09 W/m2K

Wooden beams, metal sheet, 32cm min.wool insulation, concrete slab U 0.14 W/m2K

Wooden beams, metal sheet, 25cm min.wool insulation, concrete slab U 0.18 W/m2K

Ground floor 93 m2

Concrete slab on ground, 70cm EPS insulation U 0.06 W/m2K

Concrete slab on ground, 45cm EPS insulation U 0.09 W/m2K

Concrete slab on ground, 25cm EPS insulation U 0.14 W/m2K

Concrete slab on ground, 18cm EPS insulation U 0.18 W/m2K

Leakage rate q50, m3/(h m2)

0.6 1.0 1.5 3.0

Windows 48 m2

U-value glazing/frame/total

4mm-16mmAr-SN4mm-16mmAr-SN4mm Insulated frame

0.6/0.7 W/m2K 0.7 W/m2K

4mm-16mmAr-4mm-16mmAr-SN4mm Insulated frame

0.8/0.8 W/m2K 0.8 W/m2K

4mm-16mm-4mm-16mmAr-SN4mm

1.0/1.3 W/m2K

1.1 W/m2K

4mm-16mmAr- SN4mm

Common frame 1,1/1,4 W/m2K

1,2 W/m2K

g-value 0.46 0.5 0.55 0.63

floor

iaappjjii

floor A

VcρnlAU

A

H

DH 0.42 “Nearly zero”

DH 0.58

DH 0.76

DH 0.96 “BAU”

Ventilation rate l/s, specific fan power SFP, temperature efficiency AHU HR

80 l/s, SFP 1.5 kW/(m3/s), AHU HR

85%

80 l/s, SFP 1.7 kW/(m3/s), AHU HR

80%

80 l/s, SFP 2.0 kW/(m3/s), AHU HR

80%

80 l/s, SFP 2.0 kW/(m3/s), AHU HR

80%

Heating capacity, kW 5 6 8 9

Cooling capacity, kW 5 5 5 8

Net energy need kWh/(m2 a) Space heating 22.2 36.8 55.1 71.5

Supply air heating in AHU

4.1 5.7 5.7 5.7

Domestic hot water 29.3 29.3 29.3 29.3

Cooling 13.6 11.1 9.2 15.0 Fans and pumps 7.9 8.8 10.0 10.0

Lighting 7.3 7.3 7.3 7.3

Appliances 18.8 18.8 18.8 18.8 Total net

energy need 103.2 117.8 135.5 157.7

Energy simulations

• Results of the detached house as a function of insulation level (construction concepts) and heat source

• From left to right from passive house building envelope to BAU

Energy cost data used (2011 data)• Electricity 0.0983 €/kWh + VAT (20%)• Natural gas 0.0395 €/kWh + VAT (20%) (consumption over 750

m3/year)• Pellet 0.033 €/kWh + VAT (20%)• Heating oil 0.0717 €/kWh + VAT (20%)• District heating 0.0569 €/kWh + VAT (20%) (Tallinn, natural gas boiler)

• Escalation 2% (in base case)• Discount rate 3% (in base case)• In sensitivity analyses:

Escalation 3% and discount rate 3% Escalation 1% and discount rate 3%

Incremental cost calculation• Construction cost calculation for energy performance related works and

components included: thermal insulation windows air handling units (without ductwork) heat supply solutions (boilers, heat pumps etc.)

• Labour costs, material costs, overheads, the share of project management and design costs, connection fees, and VAT were included in the energy performance related construction cost

• Global energy performance related cost was calculated as a sum of the energy performance related construction cost and discounted energy costs for 30/20 years (res./non-res.), including all electrical and heating energy use

• As the total construction cost was not calculated, the global incremental cost was used (relative to the business as usual construction):

floor

refg

floor

idiaI

g A

C

A

iRCCC

30

1,

Global incremental cost calculation: “Gas boiler” cases

• The global cost included, first divided by net heated floor area of 171 m2 • The values of the reference building (DH 0.96) subtracted

Global energy performance related cost included in the calculations, net present value, € DH 0.42 DH 0.58 DH 0.76 DH 0.96 (ref.)Building envelope (thermal insulation and windows, structures not incl.) 30602 26245 21167 17611Ventilation units (ductwork not included) 5474 3445 3445 3445Condensing gas boiler (distribution system not included) 6917 6917 6917 6917

Solar collectors 6m2 4479 4479 0 0Connection price: Gas 2455 2455 2455 2455Energy cost for natural gas, NPV 10100 14063 22208 26196Energy cost for electricity, NPV 20081 20081 20407 21422Global cost included in the calculations, NPV, € 80108 77685 76599 78047

Global incremental energy performance related cost included in the

calculations, relative to the reference building, net present value, €/m2 DH 0.42 DH 0.58 DH 0.76 DH 0.96 (ref.)Building envelope (thermal insulation and windows, structures not incl.) 75,9 50,5 20,8 0,0Ventilation units (ductwork not included) 11,9 0,0 0,0 0,0Condensing gas boiler (distribution system not included) 0,0 0,0 0,0 0,0

Solar collectors 6m2 26,2 26,2 0,0 0,0Connection price: Gas 0,0 0,0 0,0 0,0Energy cost for natural gas, NPV -94,1 -70,9 -23,3 0,0Energy cost for electricity, NPV -7,8 -7,8 -5,9 0,0

Global incremental cost included in the calculations, NPV, €/m2 12,0 -2,1 -8,5 0,0

-50

0

50

100

150

100 150 200 250Glo

bal i

ncre

men

tal c

ost (

NPV

), €/

m2

Primary energy, kWh/(m2 a)

Gas

Pellet

AWHP

GSHP

Electric

Oil

DH

BAUref.

Cost optimals with <2 €/m2 difference

Example of cost optimal: Estonian detached house3% discount rate and 2% escalation (Kurnitski et al. Energy and Buildings 43 (2011))

• AWHP – air to water heat pump, GSHP – ground source heat pump, DH – district heating• W/o PV, 4 insulation levels from left to right: 0,42, 0,58, 0,76 ja 0,96 specific heat loss H/A • H/A 0,42 ja 0,58 are calculated with solar collectors• nZEB +239 €/m2 construction cost (PE = 40 ), W/o PV +93 €/m2 (PE = 80)

nZEB

Cost optimal

Min.req.

-50

0

50

100

150

100 150 200 250Glo

bal i

ncre

men

tal c

ost (

NPV

), €/

m2

Primary energy, kWh/(m2 a)

Gas

Pellet

AWHP

GSHP

Electric

Oil

DH

Results without solar collectors

• With or w/o solar collectors? Calculate both with and without solar collectors!

• Cost optimality depended on energy source: with reasonably cheap gas, it was optimal to increase the insulation thickness by one step instead of solar collectors

Breakdown of the global cost componentsExtra global cost < extra investment cost

• Extra global cost is less than extra investment cost, because of reduced energy use• Improvement from DH 0.76 to DH 0.42 means extra investment cost of 15 943 €

corresponding to 6757 € NPV in GSHP case

30602

26245

21167

17611

5474

3445

3445

3445

9373

9373

9373

9373

4479

4479

0

0

10100

14063

22208

26196

20081

20081

20407

21422

0 20000 40000 60000 80000 100000

DH 0.42

DH 0.58

DH 0.76

DH 0.96

NPV, €

Gas

Building envelope

Ventilation units

Gas boiler

Solar collectors 6m2

Energy cost for heating

Energy cost for electricity

30602

26245

21167

17611

5474

3445

3445

3445

15542

15542

15542

15542

4479

4479

0

0

7496

10189

16356

19067

20081

20081

20407

21422

0 20000 40000 60000 80000 100000

DH 0.42

DH 0.58

DH 0.76

DH 0.96

NPV, €

Ground source heat pump

Building envelope

Ventilation units

Ground source heat pump

Solar collectors 6m2

Energy cost for heating

Energy cost for electricity

Apartment building

AB 0.23 “Nearly zero”

AB 0.32

AB 0.43

AB 0.52 “BAU“

Specific heat loss coefficient H/A, W/m2K

0.231 0.315 0.431 0.521

Heating capa-city, kW (te -21oC) 46 52 59 65

Cooling capacity, kW

48 50 51 70

Net energy need kWh/(m2 a) Space heating 7.1 13.0 21.9 28.4

Ventilation heating

4.7 6.6 6.9 7.0

Domestic hot water 35.6 35.6 35.6 35.6

Cooling 11.3 9.9 8.6 14.5 Fans and pumps 8.9 9.9 11.6 11.6

Lighting 7.0 7.0 7.0 7.0 Appliances 22.3 22.3 22.3 22.3 Total net

energy need 96.9 104.3 113.9 126.4

Apartment building3% discount rate and 2% escalation

-50

0

50

100

150

90 110 130 150 170Glo

bal i

ncre

men

tal c

ost (

NPV

),

€/m

2

Primary energy, kWh/(m2 a)

Gas

Pellet

AWHP

GSHP

Electric

Oil

DH

Office building

OB 0.25 “Nearly zero”

OB 0.33 “Low”

OB 0.45

OB 0.55 “BAU“

Specific heat loss coefficient H/A, W/m2K

0.245 0.334 0.454 0.548

Heating capa-city, kW (te -21oC)

151 160 172 181

Cooling capacity, kW

155 156 160 193

Net energy need kWh/(m2 a)

Space heating 5.8 11.4 21.9 29.0

Ventilation heating

2.8 4.1 6.2 6.4

Domestic hot water

7.4 7.4 7.4 7.4

Cooling 32.9 30.9 28.9 37.8

Fans and pumps

7.3 7.9 10.9 10.9

Lighting 18.9 18.9 18.9 18.9

Appliances 23.7 23.7 23.7 23.7

Total net energy need

98.8 104.3 117.9 134.1

-50

0

50

100

150

90 110 130 150 170Glo

bal i

ncre

men

tal c

ost (

NPV

),

€/m

2

Primary energy, kWh/(m2 a)

Gas

Pellet

AWHP

GSHP

Electric

Oil

DH

Office building3% discount rate and 2% escalation

Distance from cost optimal to nZEB

Investments needed for nZEB in the reference detached house:• +16 000 € investment in GSHP case led to 75 kWh/(m2 a) primary

energy• + 5 kW solar PV installation with about 25 000 € investment (2011 data)

• Results in about nZEB=40 kWh/(m2 a) primary energy

• Distance to nZEB the reference detached house :

41 000 € extra construction cost

239 €/m2 extra construction cost – (2011 data)

(W/o PV +93 €/m2)

• In the reference apartment and office buildings:

80-90 €/m2 extra construction cost (2011 data)

Cost optimal solutions – main principles

Building envelope:

- External wall U=0.14…0.17 (small/large building)

- Window U=0.8

- Roof and external floor U=0.09…0.14

Technical systems:

- Specific fan power of ventilation SFP=1.7…2.0

- Heat recovery 80% (possible also with exhaust air heat pump/ventilation radiators)

- Lighting <12 W/m2

- Hydronic heating (electrical not possible)

- Free cooling loop in the cooling system

Architectural preconditions:

- Reasonable compactness

- Solar shading

- Controlled window to wall ratio (“glass building” needs double skin)

Implementation into the regulation

Energy frame based on primary energy Exported energy in the energy frame Lighting&Appliances included, i.e. calculated ≈ measured Dynamic simulation required for non-residential

• Implementation was possible by just adjusting primary energy requirements, given for 9 building types

• Primary energy reqs. improved by about 20-40% depending on building type and energy source (some adjustments in the standard use of buildings and PE factor of electricity)

• Safety margin of 10 to 15% was generally applied to cost optimal primary energy

• Cost optimal regulation in force since Jan 9, 2013 both for new buildings and major renovation

Estonian system boundaries

Federation of European Heating, Ventilation and Air-conditioning Associations

REHVA system boundaries

Estonian regulation VV No 68: 2012implemented nZEB and cost optimal

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/(m2 a) kWh/(m2 a) kWh/(m2 a) kWh/(m2 a)

Detached houses 50 120 160 210

Apartment buildings 100 120 150 180

Offi ce buildings 100 130 160 210

• nZEB and low energy requirements officially given together with cost optimal minimum reqs (not yet mandatory)

• Conversion factors:

– Electricity 2.0

– Fossil fuels 1.0

– District heat 0.9

– Renewable fuels 0.75

Estonian regulation• VV No 68: 2012 – Minimum requirements for energy performance• MKM No 63: 2012 – Energy calculation methodology• Compliance assessment:

For all buildings equipped with cooling, energy performance calculation shall be based on dynamic building simulation

Requirements are specified for simulation tools, which refer to relevant European, ISO, ASHRAE or CIBSE standards, IEA BESTEST or other equivalent generally accepted method.

For residential buildings without cooling, monthly energy calculation methods may be also used.

An exception is for detached houses, which have an alternative compliance assessment method based on tabulated specific heat loss values

• Summer thermal comfort: If no cooling installed, a dynamic temperature simulation in critical rooms

required 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 is for detached house, there the compliance may be alternatively shown with tabulated values for solar protection, window sizes and window airing

How to compare min. requirements? Detached house (1/2013 data)

• Recalculation from primary energy to delivered energy needed, which can be compared in all countries

• 150 m2 detached house considered

• Degree-day correction (base 17°C) to Copenhagen, energy use for hot water heating 25 kWh/(m2a)

• 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

0

20

40

60

80

100

120

Denmark Norway Sweden Estonia Finland

Max

del

iver

ed e

ner

gy,

kW

h/(

m2a)

Oil or gas boiler

Electrical heating

Apartment and office buildings with district heating (1/2013 data)

• Maximum allowed delivered energy for heating, hot water and ventilation systems in apartment buildings and for office buildings (lighting included) with district heating

0

20

40

60

80

100

120

140

Denmark Norway Sweden Estonia Finland

Max

del

iver

ed e

ner

gy,

kW

h/(

m2a)

Apartment building

Off ice building