OPPTRE

energioppgradering av småhus itre til nesten nullenerginivå

Economic and Energy Performance of Heating andVentilation Systems in Norwegian Detached Houses
renovated towards NZEBVegard Heide, Laurent Georges
Energy and Process Engineering Department, NTNUIEA HPT TCP National workshop, Oslo, 10th of May 2022

Economic and Energy Performance of Heating and Ventilation
Systems in Norwegian Detached Houses renovated towards NZEB
•Research within the OPPTRE project••••Context:••••

OPPTRE led by SINTEF supported by the RCN
Deep energy-retrofit of Norwegian single-family detached houses“Energy renovation of detached wooden house towards nearly ZEB”

The building envelope has been upgraded significantly
Energy measures on envelope and HVAC should ideally be analyzed
together in a holistic way
In practice, design on the envelope decided first and the HVAC solution
is selected in a second step

Research question:••

Compare performance of different HVAC all-electric solutions in termsof life cycle costs (LCC) and energy efficiency
HVAC solutions are based on heat pump technologies

Methodology• Two houses from the OPPTRE architecture competition used as case• “Hus-i hage”, Malvik, 1957
• “1+1=3”, Kristiansand, 1972
• Different size, shape, construction year• One has cold attic and studio apartment• Different HVAC combinations are evaluated• Detailed building performance simulations••••

Using IDA ICE software
Multi-zone for realistic energy coverage factor
System SPF compared with literature
NS-NSPEK 3031 input data

• Economic assessment••

NS-EN 15459-1:2017
Uncertainty in investment costs

Parameters for calculating the economic performanceParameter
Calculation period (TC) [years]
Inflation rate [%]Real discount rate [%]Electricity price [NOK/kWh]Value20231.5

Investment costs• Most LCC analysis do not consider
uncertainty on investment costs• In scientific publications• Collection of costs from several references• Costs of current Norwegian market• Most of the costs were collected directlyfrom suppliers, building companies or theirwebpages• Where this was not possible, generic costs
from reports and statistics were used

• Creating a cost range• Min, mean and max values

Master thesis spring 2021: Bianca Kjellberg and Sondre Valstad JohansenMaster thesis spring 2022: Håkon Selstad ThingbøBuilding envelope
Defined 3 different insulation levels• TEK10• OPPTRE: close to proposals in architecture competition• PASSIV: passive house requirement for components
Parameter

Unit

From the architecture competition in OPPTRE

Existing
Kristians.

Existing
MalvikTEK10

OPPTREPASSIVU-value external wallW/(m².K)

0.45

0.44

0.22

0.18

0.11

U-value roof

W/(m².K)

0.5

0.3

0.18

0.14

0.08

U-value basement wall to groundW/(m².K)

0.87

3.5

0.33

0.2

0.11

U-value external floor

W/(m².K)

0.54

4.3

0.3 (4.3*)

0.18 (4.3*)

0.11

U-value internal walls

W/(m².K)

0.47

0.6

0.47

0.47

0.47

U-value windows and doors

W/(m².K)

2.6

2.6

1.6

1.0

0.8

Normalized thermal bridge value

W/(m2.K)

0.07

0.07

0.7

0.5

0.3

h-1

6.0

6.0

3.0

1.5

0.6

Infiltration*U-value 4.3 in the Malvik house

Heating and ventilation packages• Combinations• Heating (SH and DHW)
• Ventilation• Heat pump type••••Air-to-air (A2A)
Air-to-water (A2W)
Ground source (GSHP)
Compact: balanced
mechanical ventilation
with heat recovery
integration in HP unit• Extract air heat pump(EAHP)

Combination

Space-heating (SH)

Hydronic
DHW
distribution
Electric boiler

Ventilation

BalVent

Electric panel heaters, electric floor heating in bathroom.

A2A

Air-to-air heat pump in living room.
Electric panel heaters, electric floor heating in bathroom.

-Electric boiler

Balancedmechanical

A2Asolar

Air-to-air heat pump in living room
Electric panel heaters, electric floor heating in bathroom.

-Solar collectors

Balancedmechanical

A2W

Air-to-water heat pump.

Yes

Air-to-water HP

Balancedmechanical

GSHP

Ground source heat pump (GSHP) where the borehole heatexchanger should be created.

Yes

GSHP

Balancedmechanical

CHP-

Compact HP

CHPcomb

Compact heat pump unit for ventilation air heating.
Electric panel heaters, electric floor heating in bathroom.
Compact heat pump.*

Yes

Compact HP

Balancedmechanical*
Balancedmechanical*

EAHPDHWElectric panel heaters, electric floor heating in bathroom.

-EAHP

Extraction
mechanical

EAHPcomb

Extract air heat pump (EAHP).

Yes

EAHP

Extraction
mechanical

Balancedmechanical*The simulated version can also use outdoor air as heat source when heat from ventilation extract is not sufficient.

Heat pump efficiency

Energy coverage factor of the heat pump in both houses.

• Energy coverage factor• For space-heating and DHW• Uncertainty for A2A heat pump
due to heat distribution andoccupant behaviour• High coverage obtained usinghydronic distribution (floor
heating or/and convectors)• Seasonal Performance Factor (SPF)• System SPF (SPF4)• Higher for high coverage factor

Seasonal performance factor for heat pump system in both houses

Heat pump efficiency• Compare SPF in cold climate from literature• Some studies from warmer climate (Germany, Ireland)
Hp typeStudy

Air-to-air

Air-to-water

Ground source

Compact
Extract air

Numb. of HP

Building

Location

SPF low

Field, mon5

Detached

SwedenField, one year

5

Field mon.

SPF highYear

Author2.1

2009

Lidbom et al (31)Sweden2.1

2010

Nordman et al (32)

Swed. Switzerl. Scotl.

3.1

3.3

2016

Nordman et al (33)Field mon.

70

Detached

Germany

2.1

4.2

2017

Miara et al (34)

Field mon.

7

Detached

Switzerland

2.83.52021

Kuster et al (35)Field mon.

3

Detached

Ireland

2.5

5.0

2021

O Donovan (36)Switserl. Scotland

3.3

4.7

2016

Nordman et al (33)Field mon.
Field mon.

81

Detached

Germany

2.2

5.4

2017

Miara et al (34)

Field mon.

3

Detached

Canada

2.7

3.8

2021

Abdel-Salam et al(37)Field mon.

6

Detached

Switserland

4.3

4.9

2021

Kuster et al (35)Field mon.

1

Detached

Ireland

1.7

2.4

2021

O Sullvan et al (38)Field/sim.

1

Detached

Germany

1.8*

2.2*

2021

Shirani et al (39)

Field mon.

3Sweden

1.4

1.7

2005

Sakellari and Lund.(40)Multi-fam.

Estonia

1.91

2.09

2018

Thalfeldt et al (41)Multi-fam.

Finland3.7

2021

Pylsy and Kurnitsk(42)Sweden1.43

2021

Saini et al (43)Simulations
Field mon.

2

Field mon.

1

Investment of HVAC combinations• Investment for energy measureson building envelope significantly
more expansive

Specific investment costs for Kristiansand house• But contribute to indoor
environmental quality• Three ranges of investment• Lower: BalVent, A2A,EAHPDHW• Medium: A2Asolar, CHP,
EAHPcomb• Higher: A2W, CHPcomb, GSHP

Specific investment costs for HVAC combinations

Payback time
• Reference is the extract
mechanical ventilation withdirect electric heating• Scenario• Baseline• Economic support fromgovernment not included• Payback time trends• Above 10 years• Below 20 years for most low
investment combinations• Around 20 years for medium
investment combinations• Above 20 years for highinvestment combinations

Payback time
• Strongly influenced by the electricity price• Higher prices make most payback times < 20 years

Electricity price: 1 NOK/kWhElectricity price: 2 NOK/kWhGlobal costs

Kristiansand (1+1=3)
OPPTRE-target• Scenario• Baseline• Economic support fromgovernment not included• Global costs trends• Not influence by insulation level• Uncertainty on investment
important• Low investment combinations
leads to lower global cost
• Medium investment
combinations also have lower
global costs but with a significant
decrease in energy use• High investment combinations
have higher global costs (< 1000NOK/m²) but even lower energyuseHigh invest

Medium invest

Low invest

Red: TEK10 Blue: OPPTRE Green: PASSIVE

Global costs• Scenario• Baseline• Economic support fromgovernment not included

OPPTRE-target

Malvik (Hus-i-hage)• Global costs trends• Not influence by insulation level• Uncertainty on investment
important• Low investment combinations
leads to lower global cost
• Medium investment
combinations also have lower
global costs but with a significant
decrease in energy use• High investment combinations
have higher global costs (< 1000NOK/m²) but even lower energyuse

Red: TEK10 Blue: OPPTRE Green: PASSIVE

Global costs• Strongly influenced by the electricity price• With higher electricity prices (2.0 NOK/kWh)• Combinations with medium investment have lowest total costs• Compact combi heat pump (CHPcomb) has low total costs with 55 to 72 kWh/m².year electricity use
Kristiansand, Electricity price 1.0 NOK/kWh

Kristiansand, Electricity price 2.0 NOK/kWhHydronic system already existing

Costs when hydronic
distribution system isalready existingSpecific investment costs for HVAC combinations, with hydronic distribution existing.

Hydronic system to be installed

Specific investment costs for HVAC combinations. Baseline case.

Costs when hydronic
distribution system isalready existing

Hydronic system already existing

Hydronic system to be installed

Red: TEK10 Blue: OPPTRE Green: PASSIVE

Effect of new power tariffs
New proposed power grid tariffs and oldtariffs are analysed for Glitre, Elvia andNettselskapet.

Power cost (NOK/month)Power limit (kW)510ExistingNo limit

2Glitre energi

135

135

135

Elvia

115

130

Nettselskapet

365

62.5

1520167

208

208

190

280

375

470

187.5

431675919

Monthly peak power based fee for the analysed grid tariffs, based on maximum hourlyaveraged power for preceding month.

Results:• Power tariffs induce lower total energycosts• New tariff makes little difference• Difference between companies larger thaneffects of changing to new tariff

Total specific energy costs for Kristiansand house over 20 years, with different electricity tariffs. GSHP infilled and A2A shaded.

Conclusions• For the deep-retrofit scenarios considered, the relative performance between HVAC solutions is notaffected much by the insulation level.
• Many solutions with medium and higher investments have a payback back time close to the technicallifetime of the equipment, meaning 20 years which is critical.
• The higher the insulation level, the longer the payback time

• Global costs• Uncertainty on investment costs is important and affects the relative performance between HVAC solutions. The
span in investment costs for HVAC investments result in significant spans in global costs.
• Solutions with lower investment costs often lead to lower total costs but higher energy use.
• However, solutions with a medium investment cost lead to a significant reduction of the energy use for a small
increase of the total costs. Improvement of the cost effectiveness of these technologies (reduced investment
costs, grants) would unlock a large energy saving potential.

• Hydronic system enables a higher energy coverage factor, leading to a higher system SPF. However,hydronic system is seldom installed in most existing Norwegian wooden houses. This penalizes
technologies like ASHP and GSHP.
• Introduction of new grid tariffs in Norway to limit peak power will not have a large impact on costeffectiveness of HVAC solutions and their relative performance.
• The governmental grants have currently a limited impact on the relative cost performance of HVAC
solutions.

THANK YOUveigar.heide@ntnu.no, laurent.georges@ntnu.no

Energy upgrading of wooden dwellings
to nearly zero energy level