Innovative RefurbishmentGarth House

10th June 2014

Bicester Town Council

Alex Towler – BioRegional

Project Manager

Adrian Kite - Ridge

Architect

Rajat Gupta

Oxford Brookes University

Innovative Refurbishment

1. TSB Competition2. Aims and Objective3. Design Team4. Project Programme5. Innovation 6. Internal Insulation7. Secondary Glazing8. Winter Ventilation9. Summer Ventilation10. Result

Innovative Refurbishment

Technology Strategy Board competition challenge to improve the energy efficiency of existing non-domestic buildings

through innovative refurbishments.

Funded by the Department for Energy and Climate Change (DECC)

R+D Project with potential for large scale roll out.

Aims and Objectives

Develop a holistic insulation solution for historic and non-residential buildings combining: internal insulation, secondary glazing and

ventilation strategy for both winter and summer modes.•30% cheaper than traditional methods•37% carbon reduction•58% energy reduction•Improvement in comfort both winter and summer•Minimal disruption to occupants•Use of multi skilled workforce•Monitor and evaluate before and after work

Ridge – Lead DesignerAdrian Kite

Architect – Post Graduate In Energy Efficient BuildingPassive House – low energy designer / TSB Retrofit for the Future

RIBA Conservation Register / Abingdon Council Hall Museum Grade 1 Listed

BioRegional – Project Co-ordinatorAlex Towler

Sustainability Consultant. BioRegional - An environmental charity with a focus on built environment and One Planet Living

Oxford Brookes University – Monitoring and EvaluationProfessor Rajat Gupta

Professor of Sustainable Architecture and Climate Change.Director of the Oxford Institute for Sustainable Development (OISD)

Director of OISD: Low Carbon Building Group

Dr Hu Du Lecturer in Architecture and Building Simulation

OISD: Low Carbon Building Group

Design Team

Kingerlee – Main ContractorLocal Oxford Contractor

TSB / Energy Reduction ExperienceOwn Natural Building Technologies

United House - WHISCERS licenseInternal insulation contractor

BISRIA – Project AssessorIan Orme

Technology Strategy Board Julie Meikle

Design Team

Monitored and Evaluated by Oxford Brookes UniversityWinter Issues

Heating system on continuously in winter - 24hrs / dayHeavy weight structure provides slow response time

Heating system is not zoned. TRV’s not utilised.

Wasted heat loss through walls, single glazing and ground floor.Summer Issues

Council Chambers overheatingConservatory heats up in summer with no opening lights

Sufficient windows not being opened

Existing Building

Competition for funding in two funding phases:•Nov 2012: Phase 1 Application– Innovation Concepts Selected•Phase 1 funding awarded - £20k•Feb – April 2013: Phase 1 Design phase – Desk top study

•Phase 2 funding awarded - £839k•August – Sept 2013: Detail Design•Dec 2013 – March 2014: Construction Period•March 2014 – March 2015: Monitoring Phase.

Project Time Line

Innovation

A 3D laser scanner measures the internal dimensions

of a room. The digital data is then downloaded to anoff-site cutting machine.

The machine cuts the insulation boards with great

accuracy. Software optimises the cut to minimise

wastage.

The boards are delivered to site as a kit and are then

fitted to the walls with the minimum of noise, mess

and disruption.

Internal Insulation• 70mm Kingspan K18 Kooltherm

Insulated plasterboard

• 25mm treated softwood batten on existing plastered walls

• Skirting replaced

• Retain existing window mouldings by stopping insulation before existing window

• Reduced heat loss through walls

• Reduced heat loss through draughts

Internal Insulation

Existing Panelling

Secondary Glazing

Secondary Glazing

Winter Ventilation

Mechanical Ventilation with Heat Recovery (MVHR)

Provides fresh air in winter when:

•windows are not opened sufficiently

•buildings are better sealed removing natural air changes

Provides tempered fresh air without effecting internal temperatures through draughts

MVHR Installation

Second Floor Works

Aerogel Insulation

• Spacetherm C from the Proctor Group• 10 mm areogel• 18mm chip board• K-value 0.014• U-value ca 0.4

Summer Overheating

• Summer overheating potential increases due to internal insulation

• Opening existing windows is key

• Cross ventilation is required

• Conservatory needs opening vents

• Council Chambers heat gain on both sides requires heat dump vents

Summer Ventilation

Summer Ventilation

Passivent

Internal cover grilleControllablemotorised louvre

External weather louvre

Aircool wall ventilator in masonry wall

Proposed Elevations

Result

Warmer in Winter with faster more responsive heating

More efficient use of the existing heating system

Comfortable in Summer with automated natural vent in the Council Chambers

Bright

Good air quality

Happy Occupants

User focused

1+ Years Monitoring Data

Existing building character retained

Handover and Training

Building performance evaluation and Energy modelling

• Pre-refurbishment BPE• Energy assessment • Environmental audit• Occupant feedback

• Modelling post-refurbishment building performance• Energy savings• Avoiding overheating risk in summer

• Post-refurbishment BPE

Objective of BPE

• Evaluate the performance of the refurbished building in terms of energy savings, overheating in summer and the effect of combined ventilation strategies.

• Measure the moisture content of insulation materials in winter.

• Identify the role of occupants in minimising energy use, from full time staff to visitors.

• Increase the understanding of the relationship between intended performance and actual performance in-use.

Pre-refurbishment BPE

BPE methodology

Energy consumption before refurbishment

kWh/m2

Actual gas consumption was calculated based on meter readings between 18/02/2011 and 02/04/2013; Actual electricity consumption was calculated based on readings between 21/07/2011 and 18/07/2013.

Monitoring of environmental conditionsTotal 315 occupied hours in 7 weeks

starting from 18 Feb 2013Office F10 Office F13 Office F19 Office F21 Office G25

Percentage of occupied hours above 24 oC

16% 12% 0% 7% 5%

Percentage within comfort range61% 82% 37% 24% 45%

Percentage of occupied hours below 21 oC

23% 6% 63% 69% 50%

• Strong contrast between the indoor temperatures in office F10 and others. Office F10 is electrically-heated while other offices heated through radiators connected to the gas boiler.

• Electric storage heater in office F10 was continuously on during monitoring period.

• Gas boiler heating system even ran during unoccupied periods such as night-time and weekends.

• CO2 levels (1200 ppm) tend to be higher than desired in office F13.

Thermal imaging surveys

• Heat loss through white pained wall

Feedback from occupants

• Occupants feel cold in winter and hot in summer; Temperature varies during day in summer;

• Air quality is draughty, smelly and stuffy in winter;

• Low overall satisfaction in both winter and summer;

Occupants comment: ‘The heat is never stable. It is either too hot or too cold.' ‘Some area is warmer than others’.

Predicting post-refurbishment building performance

Predicted energy savings

kWh/m2

11%

49%55%

Post- refurbishment BPE

Post-refurbishment BPE methodology(May 2014 - May 2015)

• Review of handover process and commissioning

• Fabric performance: air-permeability, thermography

• Remote monitoring of energy use, environmental conditions

(external and internal) and occupant interaction with windows

• Occupant satisfaction survey using BUS questionnaires

• Technical review of building and equipment performance

• Review of the performance and usability of controls

• Structured interviews with management

Remote monitoring of energy use and environmental conditions

Remote monitoring systems• Energy use (gas and electricity) and sub-metering (5-min data start

from 11/04/2014)

• Moisture levels in fabric (5-min data start from 25/03/2014)

• Temperature, relative humidity (5-min data start from 18/04/2014)

• Indoor CO2 levels as proxy for indoor air quality (5-min data from 26/04/2014)

• Open-close window sensors (from 26/04/2014)

• Heating usage behaviour using i-buttons on radiators (15-min data start from 26/04/2014)

Monitoring following data in every 5-minute

•Total gas usage

•Total electricity usage

•Electricity usage of MVHR and 2 electric water heaters

•Heat output from boiler for space heating

Heat meter and transmitter

Sub-electricity meter and transmitter

Electricity meter and transmitter

Gas meter and transmitter

Energy metering and sub-metering

Moisture monitoring systems

Environmental monitoring systems

CO2 logger

Temperature/RH sensor Solar radiation sensor

Temperature/RH logger

Behaviour monitoring: window opening and heating usage

Temperature logger on radiator

Windows opening logger

Innovative RefurbishmentGarth House

10th June 2014

Bicester Town Council