BPE Case Study - Lyndhurst Crescent, Swindon Gupta.pdf · BPE Case Study - Lyndhurst Crescent,...

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BPE Case Study - Lyndhurst Crescent, Swindon Professor Rajat Gupta Oxford Institute for Sustainable Development, Oxford Brookes University [email protected] Building Better Buildings Conference, Bristol 3 rd February 2016

Transcript of BPE Case Study - Lyndhurst Crescent, Swindon Gupta.pdf · BPE Case Study - Lyndhurst Crescent,...

Page 1: BPE Case Study - Lyndhurst Crescent, Swindon Gupta.pdf · BPE Case Study - Lyndhurst Crescent, Swindon Professor Rajat Gupta Oxford Institute for Sustainable Development, Oxford Brookes

BPE Case Study - Lyndhurst

Crescent, Swindon

Professor Rajat Gupta Oxford Institute for Sustainable Development, Oxford Brookes University

[email protected]

Building Better Buildings Conference, Bristol

3rd February 2016

Page 2: BPE Case Study - Lyndhurst Crescent, Swindon Gupta.pdf · BPE Case Study - Lyndhurst Crescent, Swindon Professor Rajat Gupta Oxford Institute for Sustainable Development, Oxford Brookes

• BPE studies of domestic, non-domestic,

(new-build and refurbishment) over 15

years.

• Flagship PGT module on POE: 12 years

• Case studies investigation of building

performance to understand cause and

effects.

• Period of investigation: construction

stage through to in-use

• Socio-technical research using mixed-

methods approach.

• Externally-funded research:

• Innovate UK

• Research Councils (EPSRC/ESRC)

• EU Horizon 2020

• Industry

Low Carbon Building GroupBPE research portfolio

http://architecture.brookes.ac.uk/res

earch/lowcarbonbuilding/

Page 3: BPE Case Study - Lyndhurst Crescent, Swindon Gupta.pdf · BPE Case Study - Lyndhurst Crescent, Swindon Professor Rajat Gupta Oxford Institute for Sustainable Development, Oxford Brookes

Involvement in Innovate UK BPE programme

Appointed by Innovate UK

as building performance

evaluator to provide

technical advice and peer

review at the project and

programme level.

Meta-study on characteristics

and performance of MVHR

systems

(with Glasgow School of Art and

Four Walls Ltd.)

Funded by: Innovate UK Building Performance Evaluation programme

Page 4: BPE Case Study - Lyndhurst Crescent, Swindon Gupta.pdf · BPE Case Study - Lyndhurst Crescent, Swindon Professor Rajat Gupta Oxford Institute for Sustainable Development, Oxford Brookes

Our new BPE research booklet summarises our research in this area.

http://architecture.brookes.ac.uk/research/lowcarbonbuilding/resources/lcb

g-bpe-booklet-2015.pdf

Page 5: BPE Case Study - Lyndhurst Crescent, Swindon Gupta.pdf · BPE Case Study - Lyndhurst Crescent, Swindon Professor Rajat Gupta Oxford Institute for Sustainable Development, Oxford Brookes

Structure of presentation

• Context: case studies and methodology

• Findings from BPE study elements

• Assessment of fabric performance and services

• Handover procedures and user guidance

• Usability of controls

• Monitoring of actual energy use

• Monitoring of indoor environmental conditions

• Occupant feedback from interviews and surveys

• Wider lessons

Page 6: BPE Case Study - Lyndhurst Crescent, Swindon Gupta.pdf · BPE Case Study - Lyndhurst Crescent, Swindon Professor Rajat Gupta Oxford Institute for Sustainable Development, Oxford Brookes

Context: case study and methodology

Page 7: BPE Case Study - Lyndhurst Crescent, Swindon Gupta.pdf · BPE Case Study - Lyndhurst Crescent, Swindon Professor Rajat Gupta Oxford Institute for Sustainable Development, Oxford Brookes

Phase 1:

Post-construction &Initial occupancy

Nine-month study (2011)

• Capture ‘as built’ performance of

building envelope and compare it to

‘as designed’.

• Evaluate handover process.

• Map initial occupant reaction of

occupants (amenity, comfort levels,

understanding of systems).

Overview of BPE study

To broaden our understanding of actual energy performance of low-carbon homes

and close the feedback loop between design intent and outcome.

Phase 2:

In-use & Post Occupancy evaluation

Two year study (2012-2014)

• Assess overall energy use and

provision of comfort.

• Detailed analysis of usability,

effectiveness and robustness of

micro-generation.

Page 8: BPE Case Study - Lyndhurst Crescent, Swindon Gupta.pdf · BPE Case Study - Lyndhurst Crescent, Swindon Professor Rajat Gupta Oxford Institute for Sustainable Development, Oxford Brookes

Fabric testing

Thermographic survey

Air-tightness test

Co-heating test

U-value test

Commissioning review of services and systems

Commissioning checks of systems and services

MVHR tests

Review of handover process and occupant guidance

BPE methodology

Page 9: BPE Case Study - Lyndhurst Crescent, Swindon Gupta.pdf · BPE Case Study - Lyndhurst Crescent, Swindon Professor Rajat Gupta Oxford Institute for Sustainable Development, Oxford Brookes

Energy monitoring and assessment

Smart metering and sub-metering

DomEarm & benchmarking

Monitoring of environmental conditions

Temperature

Relative Humidity

CO2 Levels

Window opening

Occupant studies

Occupant satisfaction survey using BUS

Interviews and walkthroughs with occupants

Activity logging and thermal comfort diaries

BPE methodology (Phase 2 BPE)

Page 10: BPE Case Study - Lyndhurst Crescent, Swindon Gupta.pdf · BPE Case Study - Lyndhurst Crescent, Swindon Professor Rajat Gupta Oxford Institute for Sustainable Development, Oxford Brookes

• Completed in March 2011.

• Owned by Swindon Borough Council

• Code Level 5 certification, SAP rating A

• Combination of optimized airtight

building envelope and use of

renewables

• Built in one construction phase by

applying hempcrete cast into a timber

frame.

Case study background

Page 11: BPE Case Study - Lyndhurst Crescent, Swindon Gupta.pdf · BPE Case Study - Lyndhurst Crescent, Swindon Professor Rajat Gupta Oxford Institute for Sustainable Development, Oxford Brookes

13 Code Level 5 houses

for social rental in Swindon

• 1 end-terrace, 5bed, 9 persons

• 3 end-terrace, 3bed, 6 persons

• 3 mid-terrace, 3bed, 6 persons

• 6 mid terrace, 2bed, 4 persons

Case study development: Lyndhurst Crescent

Page 12: BPE Case Study - Lyndhurst Crescent, Swindon Gupta.pdf · BPE Case Study - Lyndhurst Crescent, Swindon Professor Rajat Gupta Oxford Institute for Sustainable Development, Oxford Brookes

House 6

Case study homes

House 7

Phase 2:

• House 5: mid-terrace, 2bed

• House 11: mid-terrace, 2bed

House 5

House 11Phase 1:

• House 6: mid-terrace, 3bed

• House 7: end-terrace, 3bed

Page 13: BPE Case Study - Lyndhurst Crescent, Swindon Gupta.pdf · BPE Case Study - Lyndhurst Crescent, Swindon Professor Rajat Gupta Oxford Institute for Sustainable Development, Oxford Brookes

House 6 House 7

Phase 1 Phase 2

House 6 House 7 House 5 House 11

Area m2 140 140 94 94

Typology3storey, mid

terrace

3storey, end

terrace

two-storey, mid

terrace

two-storey, mid

terrace

No. of

bedrooms3 bed 3 bed

2 bed

(One adult & two

children,

24h

occupancy)

2 bed

(Two adults &

two children,

24h occupancy)

Case study homes

House 5 House 11

Page 14: BPE Case Study - Lyndhurst Crescent, Swindon Gupta.pdf · BPE Case Study - Lyndhurst Crescent, Swindon Professor Rajat Gupta Oxford Institute for Sustainable Development, Oxford Brookes

Construction details & design performance

Main construction elementsDesign U-value

W/m2K

Ground Floor Screed over insulation on beam and block 0.12

Roof Tile on timber 0.15

Walls Rendered hempcrete cast into timber frame 0.18

Windows Timber frame, double glazing, low-e 1.4

External door Wooden 1.6

Page 15: BPE Case Study - Lyndhurst Crescent, Swindon Gupta.pdf · BPE Case Study - Lyndhurst Crescent, Swindon Professor Rajat Gupta Oxford Institute for Sustainable Development, Oxford Brookes

Services & specifications

Main heatingNIBE Fighter heat pump air-to-water. Heat pump load or weather

compensation. Underfloor heating coils

Heating

controlsTime and temperature zone control

Hot water From primary heating system. Immersion present

Solar water

heatingNu-Heat solar panel. South oriented

VentilationMechanical extract from kitchen and bathroom, fresh air supply in

other rooms, connected to the ASHP.

Renewables 4kWp photovoltaics

Target air

tightness (m3/hm2 @50Pa)

2

Page 16: BPE Case Study - Lyndhurst Crescent, Swindon Gupta.pdf · BPE Case Study - Lyndhurst Crescent, Swindon Professor Rajat Gupta Oxford Institute for Sustainable Development, Oxford Brookes

Findings from the BPE study:

Fabric tests, services and systems

Page 17: BPE Case Study - Lyndhurst Crescent, Swindon Gupta.pdf · BPE Case Study - Lyndhurst Crescent, Swindon Professor Rajat Gupta Oxford Institute for Sustainable Development, Oxford Brookes

Air permeability tests

• Measured AP values were well above the design target of 2m3/h.m2

suggesting heat losses due to air leakage paths.

• Air leakage paths were revealed behind / below various skirting boards,

windows, electrical cupboards.

• House 11: Air-permeability did not meet UK Building Regulation

(10m3/h.m2)

Phase 1(2011)

Phase 2(2013)

Page 18: BPE Case Study - Lyndhurst Crescent, Swindon Gupta.pdf · BPE Case Study - Lyndhurst Crescent, Swindon Professor Rajat Gupta Oxford Institute for Sustainable Development, Oxford Brookes

Thermal Imaging

• Air leakage through door and

window frames, window sills.

• Heat loss through exposed

wall

• Cold spot identified on wall.

• Air leakage around door

frames.

• Thermal bridging across

threshold.

• Air leakage through window

frame

Page 19: BPE Case Study - Lyndhurst Crescent, Swindon Gupta.pdf · BPE Case Study - Lyndhurst Crescent, Swindon Professor Rajat Gupta Oxford Institute for Sustainable Development, Oxford Brookes

• At the time of the inspection, the

installed systems remained to be

finally commissioned.

• Exhaust air heat pump (EAHP) and

heating system were not fully

commissioned.

• EAHP fan speed set very high.

• Underfloor heating system out of

operation on the first floor and

related control circuit disconnected.

• Uninsulated primary heating

pipework.

• Use of MVHR system during

sanding activities resulted in highly

contaminated filters with dust

particles.

Review of commissioning

Page 20: BPE Case Study - Lyndhurst Crescent, Swindon Gupta.pdf · BPE Case Study - Lyndhurst Crescent, Swindon Professor Rajat Gupta Oxford Institute for Sustainable Development, Oxford Brookes

MVHR testing

Methodology

• The airflow of all extract and vents were measured in

both houses.

• Measurements were taken on 2nd July 2013 for House

5 and on 16 April 2013 for House 11.

Findings

• The tests revealed great discrepancy between the

supply and extract rates.

House 5 House 11

Low rate (l/s) High rate (l/s) Low rate (l/s) High rate (l/s)

Extract

rates15.9 16.1 33.9 39.5

Supply rates 28.1 29.9 47.8 51.1

Supply & extract rates

balance ratio-113.21% -70.11%

Page 21: BPE Case Study - Lyndhurst Crescent, Swindon Gupta.pdf · BPE Case Study - Lyndhurst Crescent, Swindon Professor Rajat Gupta Oxford Institute for Sustainable Development, Oxford Brookes

• Heating room thermostat had

oversimplified arbitrary line scale

without labelling or numbering.

• Red light indicating whole system

operation rather than room

status.

• Masterstat without indication of

system response (no light,

sound, temperature indication).

• Room and master thermostats

had significantly different

displays and approaches.

• Not clear annotation. User

needed to experiment.

Room thermostat

Usability criteria Ranking Poor Excellent

Clarity of purpose

Intuitive switching

Labeling and annotation

Ease of use

Indication of system response

Degree of fine control

Review of control interfaces

Page 22: BPE Case Study - Lyndhurst Crescent, Swindon Gupta.pdf · BPE Case Study - Lyndhurst Crescent, Swindon Professor Rajat Gupta Oxford Institute for Sustainable Development, Oxford Brookes

Design team interview and handover

• Weak communication between

contractor, and specialists and

poor feedback to design team.

• Hempcrete drying delayed the

handover process and affected

appearance of external walls.

• Inexperience of local

contractor hindered delivery of

the innovative design

expectations.

• Handover was graduated but

home user guide was not ready

during the induction tour,

resulting in inadequate user

knowledge concerning

systems’ operation and control.

Page 23: BPE Case Study - Lyndhurst Crescent, Swindon Gupta.pdf · BPE Case Study - Lyndhurst Crescent, Swindon Professor Rajat Gupta Oxford Institute for Sustainable Development, Oxford Brookes

Energy monitoring

& assessment

Page 24: BPE Case Study - Lyndhurst Crescent, Swindon Gupta.pdf · BPE Case Study - Lyndhurst Crescent, Swindon Professor Rajat Gupta Oxford Institute for Sustainable Development, Oxford Brookes

Total electricity use (Sept 2013-Aug 2014)

Page 25: BPE Case Study - Lyndhurst Crescent, Swindon Gupta.pdf · BPE Case Study - Lyndhurst Crescent, Swindon Professor Rajat Gupta Oxford Institute for Sustainable Development, Oxford Brookes

Total carbon emissions (Sept 2013-Aug 2014)

Carbon factor (kgCO2)

Electricity: 0.517

Gas: 0.198

Page 26: BPE Case Study - Lyndhurst Crescent, Swindon Gupta.pdf · BPE Case Study - Lyndhurst Crescent, Swindon Professor Rajat Gupta Oxford Institute for Sustainable Development, Oxford Brookes

Annual energy costs (Sept 2013-Aug 2014)

Cost estimated as

£ 0.1146p /kWh

Page 27: BPE Case Study - Lyndhurst Crescent, Swindon Gupta.pdf · BPE Case Study - Lyndhurst Crescent, Swindon Professor Rajat Gupta Oxford Institute for Sustainable Development, Oxford Brookes

Breakdown of energy by end-use

0 20 40 60 80 100 120 140 160 180 200

Case C2

Design estimate (SAP)

Case C1

Design estimate (SAP)

House 11

House 5

Design estimate (SAP)

Energy by end uses (kWh/m2/annum)

Space Heating Hot Water Fans and Pumps Lighting Cooking

Electronics Refrigeration Wet appliances Small power Other

32% unregulated

35% unregulated

21% unregulated

22% unregulated

SAP tends to

underestimate

heating and hot

water loads

(REGULATED)

& does not take into

account cooking and

appliances use

(UNREGULATED)

Page 28: BPE Case Study - Lyndhurst Crescent, Swindon Gupta.pdf · BPE Case Study - Lyndhurst Crescent, Swindon Professor Rajat Gupta Oxford Institute for Sustainable Development, Oxford Brookes

Heat pump efficiency: Degree days

• Heat pump electricity use in House 11 follows temperature variations more

closely, resulting in more efficient performance.

• Baseload heat pump electricity use for hot water: House 5 (300kWh),

House 11(200kWh)

Page 29: BPE Case Study - Lyndhurst Crescent, Swindon Gupta.pdf · BPE Case Study - Lyndhurst Crescent, Swindon Professor Rajat Gupta Oxford Institute for Sustainable Development, Oxford Brookes

Environmental monitoring and

feedback from occupants

Page 30: BPE Case Study - Lyndhurst Crescent, Swindon Gupta.pdf · BPE Case Study - Lyndhurst Crescent, Swindon Professor Rajat Gupta Oxford Institute for Sustainable Development, Oxford Brookes

Living room temperatures (Min, mean, max)

• House 11 generally 1-2oC cooler than House 5.

• Temperatures in House 11 more variable due to different air-permeability

levels and heating patterns

• Temperatures within comfort levels.

• House 11 cooler in summer due to high air-permeability levels.

Page 31: BPE Case Study - Lyndhurst Crescent, Swindon Gupta.pdf · BPE Case Study - Lyndhurst Crescent, Swindon Professor Rajat Gupta Oxford Institute for Sustainable Development, Oxford Brookes

Internal temperature distribution

House 5

Living room: 30% of the time

temperatures range between 24-26oC,

and 2% of the time they range

between 26-28oC.

Bedrooms: 75% of the time

temperatures range between 22-24oC,

13% of the time they range between

24-26oC and 2% of the time they

range between 26-28oC.

House 11

Living room: 14% of the time

temperatures range between 24-26oC,

and 3.3% of the time they range

between 26-28oC.

Bedrooms: 27% of the time

temperatures range between 20-22oC,

16% of the time they range between

22-24oC.

Page 32: BPE Case Study - Lyndhurst Crescent, Swindon Gupta.pdf · BPE Case Study - Lyndhurst Crescent, Swindon Professor Rajat Gupta Oxford Institute for Sustainable Development, Oxford Brookes
Page 33: BPE Case Study - Lyndhurst Crescent, Swindon Gupta.pdf · BPE Case Study - Lyndhurst Crescent, Swindon Professor Rajat Gupta Oxford Institute for Sustainable Development, Oxford Brookes

Indoor CO2 concentration

House 5

• Living room: 72% of the time

CO2 levels range between 500-

1000ppm, and 2.5% of the time

they range between 1000-

1500ppm.

• South bedroom: 78% of the

time CO2 levels range between

500-1000ppm, 3.8% of the time

they range between 1000-

1500ppm.

House 11

• Living room: 83% of the time

CO2 levels range between 500-

1000ppm, and 1.6% of the time

they range between 1000-

1500ppm.

• North Bedroom: 75% of the

time CO2 levels range between

500-1000ppm, 15.6% of the time

they range between 1000-

1500ppm.

Page 34: BPE Case Study - Lyndhurst Crescent, Swindon Gupta.pdf · BPE Case Study - Lyndhurst Crescent, Swindon Professor Rajat Gupta Oxford Institute for Sustainable Development, Oxford Brookes
Page 35: BPE Case Study - Lyndhurst Crescent, Swindon Gupta.pdf · BPE Case Study - Lyndhurst Crescent, Swindon Professor Rajat Gupta Oxford Institute for Sustainable Development, Oxford Brookes

BUS survey• Respondents feel facilities

provided meet their needs

well.

• Lighting level overall is one of

the most appreciated aspects

of the dwellings.

• Temperatures during winter

are generally regarded as

quite comfortable.

• Summer temperatures are

regarded as less comfortable.

• Air quality is considered to be

quite satisfactory during

summer but less so during

winter.

Page 36: BPE Case Study - Lyndhurst Crescent, Swindon Gupta.pdf · BPE Case Study - Lyndhurst Crescent, Swindon Professor Rajat Gupta Oxford Institute for Sustainable Development, Oxford Brookes

Energy and water consumption

• High electricity bills. Not satisfied with heat pump performance

Occupant satisfaction

• House 5: not pleased with open plan kitchen and appearance

• House 11: very pleased with the design, layout and overall appearance

Ventilation system (mechanical ventilation and heat recovery)

• Not sufficient training on operation of MVHR

• Noise and draughts coming from MVHR.

Heating system

• Confusion about daily/seasonal operation of heat pump.

• House 5: complained for having little control over heating.

• Not sufficient guidance during the induction.

• No direct instructions in Home User Guide about operation of heating

system.

Home User Guide & Induction process

• Home User Guide very long and hard to understand

• Information included in the guide was not always accurate

Feedback from occupants

Page 37: BPE Case Study - Lyndhurst Crescent, Swindon Gupta.pdf · BPE Case Study - Lyndhurst Crescent, Swindon Professor Rajat Gupta Oxford Institute for Sustainable Development, Oxford Brookes

Wider lessons

Page 38: BPE Case Study - Lyndhurst Crescent, Swindon Gupta.pdf · BPE Case Study - Lyndhurst Crescent, Swindon Professor Rajat Gupta Oxford Institute for Sustainable Development, Oxford Brookes

Modelling tools: When modelling building energy use at the

design stage, potential issues of underperformance and occupant

behaviour need to be considered, otherwise there is a risk of

under-estimating energy use.

Documentation: ‘As built’ energy models (and commissioning

records) should be enforced to check if dwellings are built as

designed, and any changes in design or procurement are

captured.

Detailing: Careful detailing (robust details) to avoid thermal

bridging and achieve designed air-permeability rates. Rapid

diagnostics onsite and better communication between design

team, builder and sub-contractors is required given the inter-

dependencies in building performance.

Commissioning: Seasonal commissioning needs to be

encouraged for technologies such as heat pumps and MVHR

systems.

Wider lessons

Page 39: BPE Case Study - Lyndhurst Crescent, Swindon Gupta.pdf · BPE Case Study - Lyndhurst Crescent, Swindon Professor Rajat Gupta Oxford Institute for Sustainable Development, Oxford Brookes

Ventilation strategies: MVHR was adopted for achieving a high

code compliance without considering the expectations and habits

of occupants. Balance between air-tightness and ventilation should

be achieved otherwise indoor air quality may get compromised.

Guidance and training: Simple and clear guidance and handover

procedures on seasonal operation tailored to the needs of

occupants (gender, age, technical ability)

Control interfaces: Usability of control interfaces influence

occupant interaction. Controls to be accessible and clearly labelled

with an indication of system response that is rapid and detectable.

Building monitoring: Retrofitting monitoring kit is neither

particularly easy nor cheap. Building designers should design in

monitoring kit into building space anticipation of BPE studies.

Monitoring kit should be integrated within low carbon technologies.

Benefit of BPE: Without the BPE study, many of these problems

would have gone un-noticed and developed into serious issues.

Feedback loops are vital for continuous learning and improvement.

Wider lessons

Page 40: BPE Case Study - Lyndhurst Crescent, Swindon Gupta.pdf · BPE Case Study - Lyndhurst Crescent, Swindon Professor Rajat Gupta Oxford Institute for Sustainable Development, Oxford Brookes

http://architecture.brookes.ac.uk/research/lowcarbonbuilding/

Thank you!