Innovative Refurbishment Garth House 10 th June 2014

Innovative Refurbishment Garth House 10 th June 2014 Bicester Town Council

Alex Towler – Bio. Regional Project Manager Adrian Kite - Ridge Architect Rajat Gupta Oxford Brookes University

Innovative Refurbishment 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. TSB Competition Aims and Objective Design Team Project Programme Innovation Internal Insulation Secondary Glazing Winter Ventilation Summer Ventilation Result

Innovative Refurbishment Technology Strategy Board competition challenge to improve the energy efficiency of existing nondomestic 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 nonresidential 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

Design Team Ridge – Lead Designer Adrian Kite Architect – Post Graduate In Energy Efficient Building Passive House – low energy designer / TSB Retrofit for the Future RIBA Conservation Register / Abingdon Council Hall Museum Grade 1 Listed Bio. Regional – Project Co-ordinator Alex Towler Sustainability Consultant. Bio. Regional - An environmental charity with a focus on built environment and One Planet Living Oxford Brookes University – Monitoring and Evaluation Professor 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 Contractor Local Oxford Contractor TSB / Energy Reduction Experience Own Natural Building Technologies United House - WHISCERS license Internal insulation contractor BISRIA – Project Assessor Ian Orme Technology Strategy Board Julie Meikle

Existing Building Monitored and Evaluated by Oxford Brookes University Winter Issues Heating system on continuously in winter - 24 hrs / day Heavy 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 overheating Conservatory heats up in summer with no opening lights Sufficient windows not being opened

Project Time Line Competition for funding in two funding phases: • Nov 2012: Phase 1 Application– Innovation Concepts Selected • Phase 1 funding awarded - £ 20 k • Feb – April 2013: Phase 1 Design phase – Desk top study • Phase 2 funding awarded - £ 839 k • August – Sept 2013: Detail Design • Dec 2013 – March 2014: Construction Period • March 2014 – March 2015: Monitoring Phase.

Innovation A 3 D laser scanner measures the internal dimensions of a room. The digital data is then downloaded to an off-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 • 70 mm Kingspan K 18 Kooltherm Insulated plasterboard • 25 mm 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

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

Second Floor Works

• Spacetherm C from the Proctor Group • 10 mm areogel • 18 mm chip board • K-value 0. 014 • U-value ca 0. 4 Aerogel Insulation

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

Passivent External weather louvre Controllable motorised louvre Internal cover grille 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 k. Wh/m 2 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 conditions Total 315 occupied hours in 7 weeks starting from 18 Feb 2013 Percentage of occupied hours above 24 o. C Percentage within comfort range Percentage of occupied hours below 21 o. C Office F 10 Office F 13 Office F 19 Office F 21 Office G 25 16% 12% 0% 7% 5% 61% 82% 37% 24% 45% 23% 6% 63% 69% 50% • Strong contrast between the indoor temperatures in office F 10 and others. Office F 10 is electrically-heated while other offices heated through radiators connected to the gas boiler. • Electric storage heater in office F 10 was continuously on during monitoring period. • Gas boiler heating system even ran during unoccupied periods such as night-time and weekends. • CO 2 levels (1200 ppm) tend to be higher than desired in office F 13.

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 11 % k. Wh/m 2 49 % 55 %

Post- refurbishment BPE

Post-refurbishment BPE methodology • Review of handover process commissioning (May 2014 and - May 2015) • 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 CO 2 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)

Energy metering and submetering 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 Gas meter and transmitter Electricity meter and transmitter Subelectricity meter and transmitter Heat meter and transmitter