THE PLANT at Riverside Park
Joe Watton & Toby Jefferies
THE PLANT
Proposal for a combined heat and power (CHP) community energy centre at Riverside Park, Bristol. -----
Special thanks to the following people for their ongoing support throughout this project:
Personal tutor
-
Toby Jefferies
Head of Year
-
Matthew Wickens
Environmental tutor
-
Anne-Marie Fallon
Landscape tutor
-
Tim Osborn
Structural tutor
-
Gennady Malishev
Tectonic tutor
-
John Griffiths
Workshop technicians
-
Owen, Steve and Miles
Energy consultant
-
Gary Watts
Glazing consultant
-
James Petrini
Common sense consultant
-
My Mother
I. Introduction
II. Proposal
III. Spaces
1. Aspiration
19. Site Response
39. Riverside Piazza
3. How it Works
21. Plan Development
41. Riverside Park
5. The Client
23. Upper Ground Floor Plan
43. Riverside Walk
7. The Brief
25. Lower Ground Floor Plan
45. Riverside Yard
9. The Site
27. Form Rationale
47. Main hall
13. Historic Context
31. River Elevation
49. Circulation
15. Current Context
32. Park Elevation
51. Classrooms
17. Future Context
33. Road Elevation
53. Canteen
34. Yard Elevation
55. Boiler Room
35. Long Section
57. Engine Room
37. Plant Section 38. Canteen Section
IV. Structure
V. Environment
VI. Regulations
VII. Reflection
59. Structural Strategy
73. Environmental Strategy
89. Part B
95. Design Evolution
61. Overview ISO
75. Occupancy and Ventilation
90. Part M
97. Things I’d Change
62. Structural Grid
77. Heating and Cooling
93. Part J
98. Summary
63. Construction Sequence
79. Passive Lighting
64. Materiality
81. Active Lighting
65. Detailed Short Section
83. Acoustic Strategy
67. Detailed Long Section
85. Operational Carbon
69. Upper Floor Details
87. Embodied Carbon
71. Lower Floor Details
I. Introduction 1. Aspiration 3. How it Works 5. The Client 7. The Brief 9. The Site 13. Historic Context 15. Current Context 17. Future Context
“
Critical to this nationwide construction of CHP energy centres is the willingness of local authorities to allow projects to be built in central locations within the urban plan, where heated water can be distributed most efficiently with minimized heat losses.
Limiting global warming to 1.5°C will require rapid, far reaching and unprecedented changes in all aspects of society.” Intergovernmental Panel on Climate Change Report on Global Warming of 1.5 °C
The government estimates that up to 20% of buildings would be eligible for connection to CHP energy centres by 2030, which would reduce the carbon footprint of the nation’s building stock by 6%.
The Plant is a new type of building for a new type of society.
“ With the impacts of climate change becoming more apparent every year, it is now crucial that global carbon emissions are brought under control and reduced to a level which does not cause the planet irreversible harm. One of the most promising areas for reducing carbon emissions is in the generation of energy for the operation of buildings.
By generating heat and power simultaneously, CHP can reduce carbon emissions by up to 30% compared to the separate means of conventional generation via a boiler and power station.”
Bristol City Council is leading the way, with a city-wide district heating network currently under construction - made possible in large part by the culture of environmental conscientiousness which already exists throughout the city. Other authorities have struggled to get such projects through because of a lack of public backing, so Bristol could be an ideal location for a project which breaks the typological mould of traditional infrastructure buildings, bringing energy into the heart of a new community whilst passively educating building users about clean energy and encouraging a culture which prioritises sustainability.
Department for Business, Energy & Industrial Strategy Combined Heat and Power Guidance
The heating and powering of buildings accounts for around 34% of the UK’s annual carbon footprint, with individual boilers used to provide heat and regional power stations used to deliver electricity.
1.
Framing the CHP generation process like an exhibit in a museum, The Plant will demonstrate that community life and energy infrastructure can be successfully intertwined, paving the way for a new generation of community-integrated power stations to be built across the UK.
Concept
Role
Usage
Community life and energy infrastructure coexisting in one building
Flagship for energy generation at the heart of the urban masterplan
Passively educating visitors as they inhabit the building
Supply
Demand
Resilience
Less heat lost through distribution due to central location of energy centre
Balance of residential and employment buildings to ensure maximum efficiency
Battery storage to harness surplus electricity at times of low demand
2.
How it Works
Plant visible through protected windows
Plant safe to expose to visitors
Combined Heat and Power Cogeneration
Heat delivered through backup boilers if CHP engines fail
Backup boilers Heat transferred to fresh water supply through building heat exchanger in substation or plant room
cooler water Steam
National gas network Natural gas
hot water
CHP engines
Residential customers
Thermal storage
The gas network is decarbonising over time by increasing the % of biofuel in the gas composition
Heated steam from CHP process run through coil to transfer heat to water in thermal store 420V Electricity
Commercial customers
Regional electricity distribution
Local electricity distribution
400,000V
15,000V
National grid Transformers
Electricity delivered through national grid if CHP engines fail
3.
4.
The Client Bristol Energy / Bristol City Council
£12m They have so far reinvested over £12 million into the community, helping to make energy more affordable for the most vulnerable people
In order to provide customers with savings on their fuel bills, Bristol Energy had to find the most efficient ways of producing and distributing heat and power, such as through CHP generation and district heating. As a result of these improvements, less energy is now wasted delivering each kWh the company provides. In turn, this means the carbon footprint of the energy is significantly reduced.
13.2% 13.2% of homes in Bristol were in fuel poverty in 2014, compared with the national average of 9.8%
Bristol UK
120,000 80
The company now have more than 120,000 customers, which represents over a quarter of the city’s population
76g Energy can be delivered at a carbon cost of only 76g CO2e per kWh, almost a third of the National Grid’s value of 208g CO2e per kWh
Cold homes lead to around 9,600 premature deaths every winter in the UK, or 80 people per day
Bristol Energy was set up by the City Council in 2015 to reduce rates of fuel poverty within the city and help the local economy
208g 76g Bristol Energy
5.
National Grid
ST PAULS Bristol District Heat Network
St Pauls Network at phase 1 of 3
LEGEND: Riverside Park Frome Gateway Heat network in development Proposed heat network Energy centre in development
ST JUDES Proposed energy centres The Plant at Riverside Park
Riverside Park is in the ideal location for an energy centre facilitating the extension of the city-wide heat network.
CABOT CIRCUS
Old Market Network at phase 1 of 3
City Centre Network in development
Under Bristol’s Local Plan review, Frome Gateway is set to be regenerated as a new mixed use neighbourhood, containing a balance of residential and nonresidential buildings. The Plant will supply heat and power to all new developments in the masterplan, as well as some existing buildings in St Pauls and St Judes.
Redcliffe Network at phase 1 of 3
QUEEN SQUARE Temple Network in development
TEMPLE MEADS
1:5000 @ A2
0
400m
The Brief Building Spaces and Users
Engine Room Restricted Plant
Support Spaces
Exhibition Plant
Community Facilities
Battery Room
Transformer Room
Plant visible through protected windows Boiler Room =100m2
Plant safe to expose to visitors
Heat Store
Heat Store
Circulation Reception
Staff Office
Store
WCs
Main Hall
Heat Store
Kitchen
Store
Exhibition Space Class Rm1
Class Rm 2
Group Rm 1
Break Space
Group Rm 2
Upper Ground Floor
7.
Lower Ground Floor
Heat Store
WCs
Community Desk
Circulation
Canteen
Community Groups
Operators & Engineers
Park Users
Youth groups, art classes, cultural groups, sport and music clubs...
Western Power Distribution and Bristol Energy
Passing cyclists and runners as well as those using the park
Organisations
Local Schools
Universities
Product launches, company meetings and networking events
Cabot Primary School and St Nicholas Primary School
Engineering students from UWE and the University of Bristol
8.
St Agnes Church
32 to Fro me
ST PA U L S
M
The Site
A
Riverside Park, St Judes
Jerusalem CGS
Falafel Cabot Primary
RIVERSIDE PA R K
B
School
Adoption
Clifton Catholic Diocese
The Plant will be a useful events space for school classes as well as serving as an educational venue for science trips to see the power plant equipment.
St Pauls Community
A widened footbridge passing over the M32 will promote urban connectivity and open the Community Sports Academy up to more customers from St Judes.
Sports Academy
Site Area 5000m2
Broad Plain Youth Club dBs Music
B
A4
03 2
to
Ci ty
Ce ntr e
A
Bristol
Broad Plain Youth Club will be rejuvenated alongside The Plant’s construction, creating a unified community hub to serve all age groups in Frome Gateway.
Wogan coffee will benefit from increased foot traffic coming about as a result of improvement works to the riverside path into the city centre.
ST JUDES
Wogan Coffee Roastery and Shop
e
m Fro ver
1:2000
Ri
0
100m
St Nicholas Primary School
Residential
Community
Commercial
Industrial
Section A-A 1:1000
Broad Plain Youth Club to be revitalised in tandem with the development of The Plant
Topography utilised to create raised community centre looking out over the surroundings
Pathway connecting St Judes and St Pauls altered to follow a part M compliant slope
Section B-B 1:1000
Treeline retained to provide noise and pollution buffer from the motorway
Larger pedestrian and cycle lanes introduced along the full length of the site
10.
Stone wall to be reduced in height as a means of opening the site up to the River Frome
Aerial view from South - site has good access to natural light, with little overshadowing
Aerial view from West - treeline acts as effective buffer from the road and should be retained
Aerial view from East - potential for direct connection between building and park
Aerial view from North - established footbridge access to St Pauls to be widened and improved
11.
View along riverside looking away from city
View of the park entry from the city end
View along path sloping down from footbridge to the river
View along riverside looking towards city
View of site from across Newfoundland Way
12.
Historic Context Site Identity Over Time
The area currently occupied by Riverside Park has a largely industrial heritage, and was only returned to being a green space in 1975 alongside the construction of the final stretch of the M32, from junction 3 to the inner city ring road. The first terraces on the site were built in the late nineteenth century, housing workers for nearby factories which were expanding rapidly along the river Frome at the time. Land adjacent to the site has retained its industrial character since the construction of the M32, with a chemicals manufacturer, a timber merchant and a scaffolding contractor still operating just across the river, within view of the proposed scheme. It is likely that these buildings will be relocated to sites further out of the city under the Frome Gateway area masterplan. If they do, The Plant could serve as a contemporary extension of the area’s industrial vernacular, its presence serving as a reminder of the site’s historic character for future generations.
Proposal Outline
Riverside Park Outline
1:2000 1844-1888 OS map at 1:2500, 1st Edition, Bristol City Council 0
100m
Redefining the Status Quo St Pauls and St Judes played a key role in redefining Bristol’s identity after the Second World War. Anti-racism protests and riots over the latter half of the twentieth century were some of the most significant in UK history, and brought about a tangible shift in the national attitude towards race equality.
1870
“In the 18th century, St Pauls was a favoured location for wealthy slave traders, which is seen in the Georgian architecture which still exists in the area. In the 1870s, Brooks Dye Works, on the edge of St Pauls became a major local employer which led to the construction of terraced houses in St Pauls” - St Pauls Unlimited Community Partnership, 2014.
1940
The area was heavily bombed during the Second World War though funding for redevelopment was focussed elsewhere in the city, causing house prices to drop over the following years.
1950
This cheap housing attracted many of the new overseas workers who had been allowed to immigrate as part of a government strategy to help fill shortages in the labour market.
1960
Police and locals facing off on Grosvenor Rd during the 1980 riot
Crowds outside the Black and White Cafe the morning after the riot
14.
A local African-Caribbean group organised a sixty day protest in response to the racist employment policy of the Bristol Omnibus Company. The policy was soon revoked, and the actions taken became a key stepping stone towards the Race Relations Act 1968.
1980
Growing drug problems during the 70s led to a police raid on the Black and White Café in April 1980. This prompted a riot where several hundred members of the local community showed their ill feelings for the authorities, leaving 19 of the raiding policemen in hospital.
2000
Gang culture, gun violence and drug problems continued until a mass police intervention in the early 2000s. The area is now undergoing a positive regeneration under the St Pauls Unlimited Community Partnership, though gentrification is starting to threaten the character of the area and must be managed.
2030
With an established track record of breaking the status quo to reshape national attitudes for the better, St Pauls could be the ideal location for the UK’s first community-centric energy centre, serving as a model for other councils to follow.
Current Context Challenges Facing the Community
“St Pauls, Stokes Croft, and Montpelier are now in the same league as infamously “trendy” parts of London such as Shoreditch and Dalston. In what is becoming a familiar sequence, these neglected areas have absorbed waves of artists and bohemians who settled in the cheap properties, then hipsters and yuppies arrived with their bakeries and coffee shops, and the areas are now moving quickly into the overpriced era of luxury eating and accommodation.”
“Any new development around here needs to acknowledge the problems we have in the community. If it's not educating young people and helping to get them out of drugs and off the street then it’s not worth building.”
- Shad and Dael, owners of Jerusalem Falafel
- Ajit Niranjan, The Bristol Cable
1.
2.
1. A number of homeless people currently use Riverside Park as a temporary home. High rates of local unemployment and rising house prices are likely to be contributing factors.
2. The park is predominantly a transitional space. High stone walls and railings separate visitors from the river.
3. Litter and graffiti are widespread between the back of the Youth Club and the disused sports court.
15.
3.
St Pauls
Bristol
All data taken from the Ashley Ward Statistical Profile 2019
4%
10%
People in unemployment
15%
8%
People with English as a second language
55%
38%
People who own their home
26%
20%
People in social housing
25%
36%
People renting from private landlords
16.
22%
14%
People who were victims of crime in the last year
48%
35%
People who feel anti-social behaviour is a problem
140
113
Number of criminal offences per 1000 people
Future Context Frome Gateway Masterplan
x 1000 The most recent revision of the Bristol Local Plan outlines the Council’s strategic development plans for the Frome Gateway area (Policy DS5):
x 500
“At least 1,000 new homes with a mix of types, sizes and tenures at densities and forms appropriate to achieving this figure.”
“Up to 500 student bedspaces in addition to the new homes.”
“Provision of workspace, providing for a range of employment uses, as part of mixed use development.”
“Provision of community facilities required to support the residential and student development.”
“The Frome Gateway area is the first point of arrival for many visitors to Bristol City Centre. Land in this area is generally underused for a central city location.” “Frome Gateway will be developed as a new mixed use neighbourhood. Development will create a mixed and inclusive community with a diversity of land uses providing opportunities to live, work, take leisure and access services.”
Development will include...
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“Green infrastructure and public realm enhancements including improvements to public open spaces within the area.”
17.
“New walking and cycling routes to connect the development to the city centre, surrounding neighbourhoods and the wider cycle network.”
Forces
Regeneration
Site
Reconnecting St Paul’s and St Judes and improving the route into the city
Reviving neglected local pocket parks alongside construction of substations
Floor levels following contours of the existing site terrain
Park
River
Yard
Opening the hall to act as an extension of Riverside Park
Providing views into the plant areas for passers by on the riverside path
Opening the community spaces to act as an extension of the Youth Club
18.
II. Proposal 19. Site Response 21. Plan Development 23. Upper Ground Floor Plan 25. Lower Ground Floor Plan 27. Form Rationale 31. River Elevation 32. Park Elevation 33. Road Elevation 34. Yard Elevation 35. Long Section 37. Plant Section 38. Canteen Section
ST PAULS
2
1
1
7 8
4
10
6
9
3
5
3
2 1:1000 0
50m
ST JUDES
Site Response Key Site Decisions
1. Retain existing treeline as buffer between Riverside Park and the M32/Newfoundland Way 2. Reconnect St Pauls and St Judes with wider, safer and more direct access across the M32, Riverside Park and the River Frome. 3. Widen and improve the path which follows the River Frome through the park to encourage more people to walk and cycle into the city rather than driving. 4. Locate all development towards the city centre end of the site, with the scale of the building decreasing towards the park to help it sit more comfortably within the open space. 5. Remove certain paths and trees to provide a large, uninterrupted green space within Riverside Park for play and recreation, as well as for events such as markets and festivals. 6. Access to the community canteen at the busy intersection of the primary circulation routes, with it positioned away from the other community facilities to preserve functionality during large events in the hall. 7. Access to the hall and classroom spaces from the path connecting the two communities who will use the building. 8. Riverside Yard to act as a vibrant communal urban space serving both the youth centre and the Plant, suitable for ball games, pop up markets and group games. 9. Riverside Walk to provide a peaceful green route into the city centre, with the River Frome landscaped and planted to encourage wildlife. 10. Riverside Piazza to serve as the main hive of activity around the building, with activities from the main hall spilling out and into the park.
20.
Plan Development Key Programme Decisions
M32
Restricted Plant
Exhibition Plant
Community Spaces
M32
Main Hall
Riverside Park
Restricted Plant
Entry & Canteen
Exhibition Plant
Community Spaces
River Frome
Main Hall
Entry
Riverside Park
Community Canteen
River Frome
Scheme Week 1:
Scheme Week 3:
Community areas raised onto mezzanine level to give views into plant, which is located at city centre end for easy access and maintenance.
Canteen moved to lower GF to retain usability when there are events on in the hall, and opens onto sunnier south-east facing piazza on the riverside.
21.
M32
Community Spaces
Restricted Plant
Exhibition Plant
M32
Entry
Community Spaces
Riverside Park
Restricted Plant
Main Hall
Exhibition Plant
Entry
Riverside Park Community Canteen
Main Hall
Community Canteen
River Frome
River Frome
Scheme Week 4:
Scheme Week 6:
Plant equipment made visible from the main site circulation routes, and community spaces given more privacy away from riverside walk.
Heat tanks positioned behind reception to highlight community centre entrance, with canteen opened into exhibition space on lower GF.
22.
4 8
8 7
6 5
11
10 9
9
Broad Plain Youth Club
Riverside Yard 0.0m
12
13
to City Centre
Riverside W alk 0.0m
-1.0m 0
10m
River Frome -5.0m
to St Pauls
1
3
3
Upper Ground Floor Plan 1:200 @ A3
Riverside Park approx 1:30 slope
2
Riverside Piazza +3.5m
1. Reception 2. Community hall 3. Thermal storage tanks 4. Staff office 5. Storage 6. Classroom (activity layout) 7. Classroom (teaching layout) 8. Group rooms 9. CHP engine exhaust flues 10. WCs 11. Breakout space 12. Void over engine room 13. Void over boiler room
to St Judes
24.
14 12 3a
3a
Broad Plain Youth Club
Riverside Yard 0.0m
15
13
to City Centre
Riverside W alk 0.0m
0
10m
River Frome -5.0m
8 9
9
2
Lower Ground Floor Plan
3b
1:200 @ A3
3b
1. Community canteen 2. WCs 10
1
3. a) CHP engine exhaust flues 4
5
b) Backup boiler exhaust flues 4. Bar 5. Kitchen 6. Kitchen store & bins 7. Outdoor seating 8. Community support desk 9. Thermal storage tanks 10. Exhibition space 11. Storage 12. Battery room
11
13. Boiler room 6
14. Transformer room 15. Engine room
7
to St Judes
26.
Form Rationale Shaping Factors
Heritage
Vernacular
With the Frome Gateway masterplan likely to see most of the warehouses and factories along the site moved to outer city locations, there is a risk that the area may lose touch with its industrial heritage.
By embracing the vernacular of the gabled shed roof and using weathered corten cladding to mimic the tones of rusted steel on adjacent buildings, The Plant will serve as a contemporary symbol of industry, preserving the role the site has played throughout Bristol’s history for years to come.
27.
Scale
Direction
The building sits on a physical threshold between the extensive urban forms of the city and the more intimate natural forms of Riverside Park. The Plant reduces in scale as it enters the park, both in its elevations and its roof heights, respecting the transition and becoming part of the open space.
The basic massing of the building and surrounding landscape shelters the accommodation from the road whilst enabling all other elevations to face out onto Riverside Park, Broad Plain Youth Club and the River Frome.
28.
A Cathedral to Sustainability Society ’s Gathering Places Over Time
Pre-War
Post-War
Pre-Extinction
Durham Cathedral, 1093
Eastland Shopping Centre, 1967
CopenHill, 2019
Belief in religion Cathedral to God
Belief in consumerism Cathedral to commerce
Belief in self-preservation Cathedral to sustainability
29.
Evoking the Sublime
1. Beacon A recognisable beacon around which the community can congregate: heat tanks reaching into the sky in the style of bell towers. 1
1 4
2. Exposure 4
5 3
Gradient of noise and exposure as visitors pass through the building: entry, pews, altar and choir stalls vs reception, exhibition, quiet plant and CHP engines.
5
3 3. Gallery A space to look out over events going on in the main volume: mezzanine in the plant acting in a similar way to the gallery level of a church.
2
2
4. Repetition
Cathedral to God
Recognisable structure: the repeating exposed glulam portal structure will have a similar spatial and material presence to the traditional gabled church roof style.
5. Meaning A building at the centre of community life, where people can go about their activities whilst uniting around something they all believe in: God vs sustainability.
30.
Cathedral to Sustainability
River Elevation 1:200 @ A3
0
10m
Park Elevation 1:200 @ A3
0
10m
32.
Road Elevation 1:200 @ A3
0
10m
Yard Elevation 1:200 @ A3
0
10m
34.
Long Section 1:200 @ A3
0
10m
36.
Plant Section 1:200 @ A3
0
10m
Canteen Section 1:200 @ A3
0
10m
38.
III. Spaces 39. Riverside Piazza 41. Riverside Park 43. Riverside Walk 45. Riverside Yard 47. Main hall 49. Circulation 51. Classrooms 53. Canteen 55. Boiler Room 57. Engine Room
‘The Big Idea’
Stage 1 - Curiosity The monolithic flues, heat tanks and other exposed plant equipment attract the interest of people using the community facilities, as well as those passing by along the road and Riverside Walk.
Stage 2 - Learning Those who were interested make a separate visit to The Plant to get a closer look at what’s going on inside the building and find out how the CHP generation process works.
Stage 3 - Awareness Riverside Piazza: After going through the exhibition space and gaining an understanding of low carbon energy, visitors are more engaged with issues relating to climate change, more able to make changes to reduce their own carbon footprints and more likely to encourage others to do the same.
The monolithic exhaust flues at the front of the building combine with the break in the glazed waffle slab to form a clear gateway into the community facilities. Walking between the flues and appreciating their scale will leave many visitors wondering what is going on inside the building and wanting to find out more.
39.
41.
Park Landscaping Spaces Beyond the Building
A Space for Recreation
A Space for Events
A Space for Exercise
Riverside Park will be opened up and made more level to create a space in which the new community can congregate to play ball games and other leisure activities. Events in the hall can spill out onto the park over the summer months.
The new expansive space in Riverside Park will also be able to host large outdoor gatherings such as open theatre and festivals, helping to reinforce The Plant’s pivotal role at the heart of the new Frome Gateway community.
Accessible outdoor gym equipment will be dotted along the Riverside path to encourage people of all mobilities to stay fit and healthy. The same equipment will be distributed around the district heating substation pocket parks to aid rejuvenation of the area.
A Space for Play
A Space for Stopping
A Space for Moving
A Space for Wildlife
Riverside Yard will stay open to enable the safe manoeuvring of large service vehicles, which will usually come in the morning. During the rest of the day the Youth Centre will spill out and appropriate the space with outdoor play equipment.
The improved stretch of the River Frome will be made a focal point of the development, with the existing high stone wall reduced in height to create regular viewing points along the river, and a stepped run of seating terraces in front of the building.
Riverside Walk will become a pivotal commuter route, with the variety of new planting and landscaped spaces creating a vibrant green pathway into the city centre. This will encourage people to get to work under their own steam rather than going by car.
Improvement works will be made along the length of the River Frome as it passes through the site, with added banks and meanders to break up the current and create more enriched habitats for a broader range of wildlife.
1
River Landscaping
2
1. The stepped ramp up to Riverside Piazza will be planted with native wildflower and grass species to encourage a more resilient ecosystem of insects and birds.
2. A new row of silver birches will provide shade for those on Riverside Walk during the summer months, whilst helping to filter early morning glare entering the building over the winter.
3. Benches will be carved into the new landscape to offer a stopping point where people can appreciate the river and the wildlife that surrounds it.
4. Banks and meanders will be added to the River Frome to vary the flow rate of the water, providing the platform for a broader range of plant and animal species.
3
4
43.
Riverside Yard Engaging the Youth Centre
Broad Plan Youth Club has been running for over a century, traditionally focussing on physical activities such as boxing and martial arts to teach discipline amongst young people in the community. Though this approach has undoubtedly benefited many, the Bristol Council statistical profile indicated that a number of local people feel youth violence is an issue, and that more options should be made available to young people who want to develop interests in areas away from violence. The Plant will act as an extension of the Youth Centre, offering spaces which are designed for learning and enabling them to engage in a wider range of non violent activities. The exposed plant equipment may inspire some to develop interests in physics and energy production.
Broad Plain Youth Club Riverside Yard will be a shared breakout space which enables both buildings to work as one, though it needs to be left mostly open to enable large vehicles to turn around in the site and access the engine room.
New axis of circulation to create a direct link between the Youth Centre and The Plant, indicated by a change in floor finish. Permanent activity zone containing outdoor leisure equipment which will be left out full time and made available to the public. Temporary activity zone to be cleared after each session so that delivery and maintenance vehicles are able to turn around safely.
45.
06:00
13:00
An early morning delivery of clean lubricant oil, used to ensure the steam turbine runs smoothly. The Plant’s manager from Bristol Energy comes out to coordinate the process.
The Youth Centre are having a family BBQ day, with children playing outdoor games in Riverside Yard using equipment wheeled out from their storage room.
46.
Gable Ridge Detail Prefabricated Roof Panels
Finish Screw-fixed standing seam corten cladding over the gable of the portal frame, with corten coping profile fixed to the ridge
Fabric 270mm SIPS panel with single 15mm OSB sheet on top side and double on lower side, taped on the inner leaf at corner junctions to ensure airtightness
Structure 800x250mm glulam portal with flitched steel plate connection and recess cut for ridge beam to provide longitudinal stability
48.
Heat Tank to Roof Junction 1:10 @ A3
1. 300x100mm curved channel section ringbeam 2. 20-40mm perimeter ballast
A
A
A-A
B
• • • •
District heating water supply Inner lining to tank manufacturer’s spec 100mm curved inner rigid insulation panels 20mm spacer with steel channel straps at 1m vertical centres to align with insulation • 100x50mm vertical steel channels • 200mm curved outer rigid insulation panels with waterproof finish • Perforated corten panels system at 2m vertical centres
2
1
B-B • • • • • • •
Sedum and wildflower mix Lightweight substrate Drainage layer with filter fleece Root barrier Waterproof membrane 270mm structural insulated panel Acoustic timber battens at 200mm centres with lighting fixtures between
B
49.
51.
Classroom Layouts 1:200 @ A3
Mode 1:
Mode 2:
Mode 3:
One teaching layout and one activity layout
Same layout in both rooms
Whole space open doing the same function
52.
Canteen Roof Detail Prefabricated Waffle Slab
Finish Pre-cast concrete pavers raised on pedestals to sit flush with double layer of toughened laminated safety glass, with both draining onto a waterproof breather membrane
Fabric 150mm rigid foamglass insulation with triple glazed panels in openings and channels cut out to create space for MVHR ducts
Structure 250mm lightweight concrete waffle slab sitting across two grid bays, with steel reinforcement bars running in both directions
54.
Riverside Facade Detail Prefabricated Wall Panel
Structure 800x250mm glulam portal with steel baseplate cast into concrete floor slab to create a rigid moment connection at the foot of the column
Fabric 2m band of triple glazing with automated openings 1.2m band of low-g polycarbonate panels 200mm rigid insulation with openings into engine room
Finish Timber framework acting as structural support for prefabricated wall panel, with glazing and polycarbonate being fixed in from behind.
55.
Plant Operation The CHP Process 9
7. Hot exhaust gases from the boiler are taken through the heat exchanger to preheat incoming fresh air, increasing the rate of complete combustion.
10. The backup boilers will lie dormant for most of their lifetime, producing steam to directly feed the heat tanks on rare occasions when the CHP engines fail.
8. After recycling the heat energy, exhaust gases are passed through a series of chemical converters and reducers in the basement to filter out harmful pollutants.
11. A large battery reserve will harness any excess electricity when the CHP engines are running at a surplus, and will conversely help bridge the gap at times of deficit.
9. Once filtered, the clean gases are taken a safe height above the public realm and released through the exhaust flues. 7
12. Stands exhibiting key parts from the equipment being used in The Plant, with explanatory text accompanying each to help visitors understand the process going on around them. 13. A full steam turbine removed from its acoustic housing and exposed for visitors to see.
5
14. Cycling machines hooked up to small scale generators for visitors to see how their human power output compares to the CHP generators.
1, 2 8, 11
3 4 10
13
6 1. Natural gas is fed into the boiler within the CHP engine and combined with preheated fresh air from the heat recovery unit above.
14 12
2. The combustion heats coils of water passing through the boiler, creating a jet of high-pressured steam. 3. Pressurised steam passes through the high, intermediate and low pressure turbine sets, causing the axial shaft to rotate.
5. Electricity is sent through the transformers to be stepped up to voltages suitable for local and national transmission.
4. The turning shaft is connected to a generator at the end of the CHP engine. Current induced in the turning rotor creates a usable potential difference.
6. Hot steam leaving the turbines is taken to the heat tanks through insulated pipes, and passes through another coil to transfer heat to the district heating water supply.
Getting sidetracked on the way to yoga
58.
IV. Structure 59. Structural Strategy 61. Overview ISO 62. Structural Grid 63. Construction Sequence 64. Materiality 65. Detailed Short Section 67. Detailed Long Section 69. Upper Floor Details 71. Lower Floor Details
Natural Materials The building will be supported by a frame of glue laminated timber portals and beams resting on the concrete slab and retaining walls beneath. The use of raw, elemental materials such as timber and weathered corten steel will respect the parkland setting and enable the building to feel more humane - breaking away from the sterile, grey vernacular most commonly associated with infrastructural buildings.
59.
Keeping it Simple Two basic extruded volumes contain the entire building. This simplicity of structure means that there are a very small number of material changes and resultant thermal bridges for a building the size of The Plant. With the long repeating structure, the construction, maintenance and disassembly of the building will be simpler and components are more likely to be recycled or reused at the end of its design life.
60.
Roof Finishes: Sedum roof build up over the community wing to encourage wildlife and give some green space back to the site. Standing seam corten wrapping over the gable of the portal frame.
Overview Exploded Isometric
Primary Structure: Glulam portal frame joined at minimal flitched connections and held in place by steel base plates cast into the concrete floor slab and retaining walls.
Upper Ground Floor: Acoustic dowel laminated timber floor supporting stud partitions internally, whilst prefabricated structurally glazed waffle slab panels provide a light-permeable base for Riverside Piazza.
Elevations: Groundworks:
All four façades of the building to have prefabricated panel systems fixed onto the outside of the primary structure, creating a continuous thermal envelope around the building’s surface.
Reinforced concrete floor slab and retaining wall sitting on a layer of rigid foam glass insulation and tanked up to ground floor level throughout to prevent the ingress of any moisture to the water-sensitive plant equipment.
61.
Structural Grid 1:400 @ A3 7.5m
10.5m
7.5m
7.5m
5.0m
250mm 400mm
Glulam roadside column 3.5 - 7.0m
Glulam hall undercroft column 0.0 - 3.0m
Glulam canteen undercroft column 0.0 - 3.0m
62.
500mm
250mm 400mm
Glulam portal column 0.0 - 7.0m
250mm 400mm
800mm
250mm
Reinforced concrete retaining wall -3.0 - 3.5m
Construction Sequence Build Stages and CDM Considerations
Foundations and retaining walls
Plant equipment and primary structure
Prefabricated wall and roof panels
Cladding and sedum roof
63.
1. Site surveyed and trial pits dug to assess the ground conditions, checking for any toxic or hazardous materials such as asbestos left from the demolition of buildings which previously occupied the site 2. Construction site boarded off, with diversion of public right of way clearly signposted and advance notices put up around the area to inform the public of the planned duration of the construction phase 3. Removal of existing hard landscaping and excavation of soil beneath to create space for basement and lower ground floor 4. Redistribution of the excavated material to build up levels around the site in accordance with the landscaping plan 5. Casting of insulated concrete floor slab and retaining walls, with openings created for the district heating pipelines and polyurethane movement joints around the plant equipment slabs to reduce vibration transmission 6. Crane delivered and erected on site, with the ground assessed for adequate stability beforehand 7. Primary plant equipment delivered to site and craned into position, left in its weatherproof enclosure until later in the construction 8. Primary glulam structure delivered to site and craned into position, fixed into receiver plates cast in the concrete floor slab and flitched together by the structural contractors. 9. Insulated wall and floor panels prefabricated off site to minimise on site hazards, then craned into position and fixed to the primary structure to complete the building’s continuous thermal envelope 10. Cladding, sedum roof and surface finishes applied to complete the weatherproof layer around the building 11. No facade window is more than 6.5m from the ground. During operation, these will be cleaned from outside using a water-fed pole system. The roof lights will be cleaned from the roof by workers with appropriate safety equipment.
Materiality Building Fabric Rationale Corten Steel
Construction materials for The Plant will be extracted, processed and manufactured in the UK wherever possible, helping the national economy whilst reducing the embodied carbon footprint of the buildng fabric.
Port Talbot Steelworks, South Wales A resiliet weathering metal which responds to the industrial heritage of the site whilst suiting the longlasting nature of the building. Raw steel will be processed at the Port Talbot steelworks using a high proportion of recycled steel and then sent to a corten manufacturer nearer to the site for the production of standing seam rolls and perforated panels.
Glue Laminated Timber Buckland Timber, Devon Using timber for the primary structure rather than concrete or steel will help the building to feel more humane, reinforcing the idea that infrastructural buildings can be integrated within the community.
Reinforced Concrete
The COâ‚‚ absorbed during the life of the softwood conifer will be sequestered in the building, helping to reduce its embodied carbon footprint. Like all components for The Plant, the glulam members will be no longer than the loadfloor of a common articulated lorry, meaning no special measures will need to be made for delivery, avoiding a potential source of high transport emissions.
Aberthaw Cement Plant, South Wales Though it has a high initial embodied carbon footprint, reinforced concrete construction will be the most durable and materially efficient way of supporting the various pieces of heavy equipment within The Plant
Bristol
64.
Cement for the grond floor slab and retaining walls will be produced in Tarmac’s Aberthaw plant just outside Cardiff, using reinforcement bars from Port Talbot Steelworks and recycled aggregates from demolition works in Bristol.
Detailed Short Section 1:125 @ A3
0
10m
66.
Detailed Long Section 1:125 @ A3
0
10m
68.
1 2
3 4 2 1 3 4
Classroom
Mezzanine
1. Drainage detail for corten runoff to corten manufacturer’s spec 2. Retaining wall brought to upper floor level with receiver base plates anchored into top surface for glulam columns to bear onto 3. Dowel-laminated timber floor with recessed members creating service channels for artificial lighting and sprinkler systems 4. Roxul (or equivalent) rigid stone wool drainage insulation layer around outside of retaining wall
1. 600mm grated steel access deck on raised pedestals for maintenance of skylight and green roof 2. Railing for automated rooflight shading canopy rollers 3. Timber worktop looking out across boiler room 4. AIR-board or equivalent acoustic polycarbonate partition to bring classroom background noise level below 35dB, in accordance with BB93 guidance
69.
3
3 1
2 1 2 4
Riverside Wall
Hall Entry
1. Concealed automated mechanical louvres to protect against morning glare and prevent overheating 2. Chain actuator opening triple glazed windows to control air supply for passive stack ventilation 3. Acoustic battens reduce reverberations in boiler room and hall whilst creating service channel over glulam portals 4. Fresh air inlet for back up boiler units
1. Triple glazed aluminium bifold doors on dual roller system allowing hall to open out onto the piazza and park 2. Sprung timber raised access floor on adjustable support pedestals 3. Prefabricated double sheet polycarbonate wall panel supported by timber framework
70.
2
1 2 1
3
3
Basement Walkway
Riverside Landscaping
1. Raised access deck over district heating pipelines and MVHR supply duct 2. Tanking around basement formed from Preprufe (or equivalent) membrane chemically bonded to underside of slabs and lapped over bituthene membrane outside retaining wall 3. Permeable drain pipe in bed of crushed stone at the base of compressed hardcore backfill
1. 1:15 slope with 2.5m landings to comply with part M requirements 2. Retaining walls backfilled with soil to grow native plant species and encourage wildlife along the river 3. Stepped retaining walls on type 1 hardcore made up of recycled aggregates from the demolition of the derelict sports court on site
71.
1 2
3
1
2
3
Plant Acoustic Plinth
Bar / Servery
1. Acoustic movement joint to reduce noise transmissions through vibration of the concrete floor slab 2. Reinforced concrete slab thickened beneath plant equipment to take the increased load 3. Micro piles combined with deepened floor slab to support additional load of plant equipment
1. 2 x 10mm toughened laminated safety glass 2. Obscured triple glazed unit forming a continuous thermal envelope with rigid insulation layer 3. Acoustic partition to reduce airborne noise transmission from the kitchen into the canteen
72.
V. Environment 73. Environmental Strategy 75. Occupancy and Ventilation 77. Heating and Cooling 79. Passive Lighting 81. Active Lighting 83. Acoustic Strategy 85. Operational Carbon 87. Embodied Carbon
Low Energy The simple roof profile improves the building’s form factor whilst requiring fewer material changes and complex junctions, meaning less heat is likely to escape through thermal bridging and infiltration. The lower ground floor is recessed into the bank to enable efficient site circulation, though this has the added benefit of sheltering the spaces adjacent to the retaining wall and reducing the amount of heat lost through their envelope.
73.
Passive Operation The building will operate passively for large parts of the year, with stack driven ventilation giving a sufficient air supply outside the winter months and the inhabited rooms orientated towards the south to minimize the amount of artificial lighting required. All active heating and cooling for the building will be delivered through a MVHR unit, with its sensor system feeding into a live building energy display board near reception to educate visitors about building energy consumption.
74.
Ventilation Strategy Air Changes by Space
The Plant will use a mechanical ventilation heat recovery unit (MVHR) to provide all spaces with a sufficient supply of fresh air throughout the year. Additional mechanical heating and cooling can be introduced to the supply during particularly hot or cold days where the air needs to be preconditioned. The MVHR unit will have an efficiency of 95%, meaning the large majority of outgoing heat will be recovered, substantially reducing the energy demand of the building during the heating season. It will run on the ‘low’ setting, with users able to increase the ventilation rate as required.
Ventilation Requirement High
Medium
Low
Fresh air supply
Exhaust air extract
Air changes per hour Zone
Boost
Middle
Low
Kitchen
25
10
4
Canteen
12
5
2
Plant areas*
10
4
2
WCs
10
4
2
Main hall
5
2
1
Classroom spaces
5
2
1
Circulation areas
5
2
1
Volume weighted building air changes per hour
*CHP engines and boilers will have separate direct supply of preheated fresh air
1.5ac/h 75.
MVHR
Through floor
Through wall/ceiling
Duct drop
winter preheating
summer cooling
Ventilation Losses: Reception/circ Reception/circ
Vv (ventilation volume) = 8489m3 neff (air changes per hour) = 1.5/h c (heat capacity of air) = 0.33 Wh/m³K Gt (degree hours per year) = 50 kKh/yr e (heat recovery unit efficiency) = 95% Q = 8489 x 1.5 x 0.33 x 50 x 0.05
60 40
Main Main Hall hall
Morning zumba
Classroom 11 Classroom Upper Ground Floor Spaces
Classroom 2 Classroom 2
Toddler group
10
15
Morning yoga
SEN class
Art group
Visiting school classes
Group Room Group room 11
Group room Room 2 Group 2
- 8.25 kWh/m2year Staff Office Staff office
40
Choir rehearsal
Youth group
15
20
Meditation classes
Martial arts
Evening fitness classes
10
20
20
Language drop in classes
After school club
Evening fitness classes
30
30
15 Morning yoga
30 Company conference
15
= 28,014 kWh/year ÷ 3395m2 treated floor area
5 Cleaners
80
Total ventilation losses:
Q = Vv x neff x c x Gt x e
5 people Gen. occupancy
2
8
6
Music lessons
Cultural groups
Board games club
4
8
8
Music rehearsals
Community support groups
University societies
1
2
1
Office work
Lunch
Office work
2
Breakout space Space Breakout
Gen. occupancy
Occupancy Gains: 2
WCs WCs
Gen. occupancy
Total no. occupied hours per day:
50
50 20
2138 hours Heat generated by the average person: 80W Total heat gained from occupants per day:
Canteen Canteen
Morning service
Lower Ground Floor Spaces
Kitchen Kitchen
Exhibition Exhibition space Space
50 20
General service
Lunch service
Evening service
General service
5
3
5
3
5
Morning service
General service
Lunch service
General service
Evening service
5
15
5
Morning occupancy
Daytime occupancy
Evening occupancy
171 kWh/day x 168 days per year in the heating season:
2
WCs WCs
Gen. occupancy
28,734 kWh/year ÷ 3395m2 treated floor area
+ 8.46 kWh/m2year
00:00 00:00
02:00 02:00
04:00 04:00
06:00 06:00
08:00 08:00
10:00 10:00
12:00 12:00
14:00 14:00
16:00 16:00
18:00 18:00
20:00 20:00
22:00 22:00
00:00 00:00
Projected occupancy profile for The Plant during an average weekday. A large proportion of the building’s heating will come through occupancy gains, as stale warm air from high occupancy areas is run through the MVHR to heat the fresh incoming air. 76.
Summer Operation Mixed Mode Conditioning
1. During the summer months the plant space will receive significant solar gains from the morning and early afternoon sun. Automated opening windows will run along the river facade with parallel automated roof lights along the ridge to allow hot air to escape through buoyancy driven stack ventilation.
3
1
2
2. All community rooms will have manually openable windows, with the stack effect in the plant room drawing air through to provide passive ventilation and cooling where necessary.
5 3
4
3. On overcast days when stack ventilation is less effective, the MVHR system will switch on fully to provide all fresh air for the building.
Section A-A
4. The undercroft spaces on the lower ground floor will have no windows on the retaining wall faces, so the MVHR will provide fresh air, supplemented with mechanical cooling where necessary. 5. Underfloor heating will run through all habitable spaces and will activate automatically when natural gains from sunlight, occupancy and plant equipment are not sufficient to maintain a comfortable internal temperature.
B 3 A B
4
5
Section B-B
A
77.
Winter Operation Minimizing Heat Losses
1. The low U-value thermal envelope, combined with the extensive earth sheltering on the lower ground floor, will mean The Plant loses far less heat through infiltration and thermal bridging than other buildings of a similar scale. This will significantly reduce the energy required to heat it during the winter months. 2. The MVHR system will deliver warmed fresh air through ducts in the wall and floor fabric, with extract points over areas such as the plant, hall and kitchen which are more likely to experience occupancy gains.
2
2
3 1
3
3. Underfloor heating will preheat the inhabited spaces each morning during winter, and will also be available during the day on occasions where natural gains from sunlight, occupancy and plant equipment are not sufficient to maintain a comfortable internal temperature.
Section A-A
B
A
2 3
B
Section B-B
A
78.
1
Passive Lighting Daylighting Strategies
The classrooms and other spaces on the roadside wing will receive secondary daylight from the solar core, supplemented by ambient daylight from their windows and artificial lighting where necessary.
Active lighting will become necessary in the late afternoon and into the evening as the treeline and form of the terrain means limited light will be available from the west.
Being recessed into the ground on the North side and fully exposed on the south, the building’s orientation minimizes heat losses through cooler north façades and makes the most of the available sunlight entering the site along façades with a south-facing aspect.
Summer sunpath
Winter sunpath Solar core
Midday sun position
Polycarbonate panels with a low g value allow light into the engine room whilst keeping it from overheating - something which is important for the effective functioning of the combined heat and power engines.
Minimal shading to the south and east of the site means there is high potential for natural light to illuminate the habitable spaces through the morning and early afternoon.
The upper row of triple glazing will allow light to reach deep into the plan, whilst the band of low g value polycarbonate below will moderate the sunlight to protect those nearer the facade.
The hall, boiler room and engine room will be finished with bright, reflective surfaces to act as a solar atrium, gathering a large amount of natural light from openings in the walls and roof throughout the day and passing it on to the community rooms on the more shaded side of the building.
Direct sunlight Diffuse/ ambient light Automated roller blind
Solar Gains: Total solar gains:
Q = ΣG x A x r x g G - average annual solar irradiation on surface (kWh/m²yr) A - area of opening, including frame (m²) r - reduction factor for dirt, shading etc g - fraction of solar irradiation transmitted Q = 9,312 kWh/year
Protection from Overheating The glulam columns and timber framework along the riverside facade will provide solar shading around the middle of the day when the sun is coming from the south and the building needs most protection from overheating.
÷ 3395m2 treated floor area
+2.81 kWh/m2year
Ambient daylight will still be able to enter from the east, preserving a good quality of light in the main hall and boiler room when combined with the effect of the roof lights.
Protection from Glare There is potential for the low morning sun to cause glare in spaces which look out to the east. Automated light sensitive roller blinds will be concealed between the structure and the curtain wall and will activate when a light sensor detects there is glare in the habitable spaces. Diffuse light will still be able to pass through the polycarbonate panels, giving sufficient illumination when combined with the roof lights.
80.
Indoor Artificial Lighting The exhibition space will receive little natural light, particularly towards the late afternoon and evening when the solar core is less bright. However, this low light level has been factored in to the design to complement the needs of the space. LED spotlights concealed in the DLT floor above will focus attention on the exhibited plant equipment to create an intimate atmosphere where visitors are able to be fully immersed in the displays before they move into the boiler room and see the CHP process occuring live in front of them.
81.
Outdoor Artificial Lighting After dark, the exhaust flues and heat tanks will be lit up to highlight The Plant’s presence as a central beacon to those passing through the area. The light level will fade into the night in accordance with the obtrusive light curfew for Frome Gateway set out by the Council. Along with the ambient light radiating out of the building, this will supplement primary illumination from recessed LED pavement lights along all paths through the site to create a safe and open nighttime environment which people feel comfortable to walk though after dark.
82.
Acoustic Strategy
Managing Sound Transmissions
The steam turbines in the combined heat and power engines have a sound output of around 80dB, brought down to 65dB by the system’s acoustic enclosure. This noise will be further reduced to 50dB by the concrete and polycarbonate cell acoustic wall containing the engine room. The background hum of the CHP engines will be just audible from the adjacent boiler room and hall, but not loud enough to disrupt any activities. The group rooms and classrooms need to be able to accommodate quiet activities whilst the main hall will be used for activities with lower noise sensitivity such as youth groups, exercise classes and community events. It is necessary to consider all paths the CHP engine’s sound could follow in order to prevent it from disrupting the usability of the community spaces (see opposite).
Source Room High noise output > 70dB Moderate noise output > 50dB
Receiving Room High noise sensitivity < 35dB Moderate noise sensitivity < 50dB
83.
Flanking
Airborne Transmission
Reverberation
An acoustic isolation joint runs around the outside of the CHP engine plinth to lessen the effect of vibrations passing to the main concrete floor slab and then through into the boiler room and other inhabited spaces.
A light-permeable acoustically insulated partition reduces the sound pressure level entering the classrooms to an acceptable 35dB, and provides secondary daylight from the boiler room and mezzanine.
50mm timber battens give the ceiling an irregular profile to diffuse sound waves, reducing reverberations whilst creating a passage over the glulam portals for services such as lighting and sprinkler systems to pass.
84.
Corten Roof and Walls:
Sedum Roof:
• Standing seam corten sheet • 25x50mm battens aligned with seams @ 937.5mm centres • 270mm SIPS panel with 15mm OSB on either side • 50mm service cavity (walls only) • 2x 12.5mm gypsum board
• • • • •
Area: 1341 m² U-Value: 0.08 W/m²K Heat Loss: 106.9 W/K
Sedum and wildflower blend Lightweight growing substrate Filter fabric & reservoir layer Waterproof membrane 240mm SIPS panel with 15mm OSB on either side • 12.5mm gypsum board • 50mm sq timber acoustic battens Area: 494 m² U-Value: 0.08 W/m²K Heat Loss: 39.4 W/K
Double Polycarbonate Layer:
• 2x 60mm 6 layer polycarbonate panel
Area: 190 m² U-Value: 0.35 W/m²K * Heat Loss: 66.9 W/K
Area: 233 m² U-Value: 0.09 W/m²K Heat Loss: 22.0 W/K
Waffle Slab Roof: • 25mm paving slab on drainage pedestal • Waterproof membrane • 150mm rigid foamglass insulation • 250mm reinforced concrete waffle slab
Area: 703 m² U-Value: 0.60 W/m²K Heat Loss: 421.8 W/K
Triple Glazed Openings:
Plant Access Door:
• • • • •
• 480mm aluminium sheet covering • 80mm lightweight insulation • 480mm aluminium sheet covering
6mm glazed panel 12mm argon cavity 6mm glazed panel 12mm argon cavity 6mm glazed panel
Area: 641 m² U-Value: 0.70 W/m²K * Heat Loss: 485.9 W/K
Area: 19 m² U-Value: 0.80 W/m²K Heat Loss: 15.2 W/K
Concrete Wall Panels:
Retaining Walls:
Concrete Floor Slab:
• 100mm reinforced concrete panel • 200mm rigid insulation • 50mm service cavity • 2x 12.5mm gypsum board
• 500mm reinforced concrete retaining wall • 300mm rigid draining insulation • Min 500mm recycled hardcore backfill
• 200mm reinforced concrete floor slab • 300mm rigid foamglass insulation • Min 500mm recycled hardcore backfill
Area: 738 m² U-Value: 0.10 W/m²K Heat Loss: 51.0 W/K **
Area: 2451 m² U-Value: 0.06 W/m²K Heat Loss: 101.2 W/K **
* Membranes not included in thermal calcs
Fabric Losses: Passivhaus Energy Criteria: Total fabric losses:
Q = Σ AiUi + Σ lk Ψk + Σ xj Σ AiUi (losses through component build ups) Σ lk Ψk (losses through linear thermal bridges) Σ xj (losses through point thermal bridges)
“The annual Space Heating Energy Demand is not to exceed 15 kWh per square meter of net treated floor area”.
Riverside Park Home to Britain’s first Passivhaus Energy Centre
The Plant will comply with the Passivhaus requirement, with 13.78 kWh per m²yr used to heat the building and up to 1.22 kWh per m²yr available to provide mechanical cooling over summer if necessary.
Building designed with near thermal bridgefree construction, meaning component losses can be taken as the total value.
Q = Σ AiUi = 1310 W/K x heating degree hours in Bristol for base temperature of 16°C: = 65,522 kWh/year ÷ 3395m2 treated floor area
Glazing Losses -8.14 kWh/m²yr
Underfloor Heating
- 19.30 kWh/m2year
+13.78 kWh/m2year
Appliance Gains:
Other Fabric Losses -11.16 kWh/m²yr
Solar Gains
Total appliance gains:
+2.81 kWh/m²yr
Q = ΣP + ΣA
Appliance Gains +2.50 kWh/m²yr
Σ P (heat given off by plant equipment) Σ A (heat given off by building appliances) = 8,488 kWh/year ÷ 3395m treated floor area 2
Ventilation and Infiltration Losses
Occupancy Gains +8.46 kWh/m²yr
-8.25 kWh/m²yr
+2.50 kWh/m year 2
Losses
Gains 86.
Embodied Carbon Using the Right Materials
Quality Shoe
Cheap Shoe
Quality Building
Cheap Building
Higher initial cost and use of materials
Initial saving on cost and materials
Higher initial cost and use of materials
Initial saving on cost and materials
Worn for exercise, work and going out
Only suitable for going out in, more shoes required
Used as power plant, cafe and community centre
Serves only one role
xn
x3 Quality materials, lasts for three years
Needs replacing each year despite less intensive use
Quality materials, lasts for three generations
x3 One pair of shoes, more comfortable to wear, less material required
Quality materials recycled at end of life
Nine pairs of shoes, less comfortable to wear, more material required
Knocked down and replaced after 30 years
xn One building, more benefit to the community, less material required
Quality materials recycled at end of life
Several similar buildings, less benefit to the community, more material required
Design for Disassembly End of Life Reuse
Accessible Connections All connections between building components to be physically and ergonomically exposed to enable access for disassembly at the end of the buildingâ&#x20AC;&#x2122;s design life. Mechanical fixings used instead of welding, casting and adhesives wherever possible, such as on the corten standing seam and glulam baseplates.
Repeated Components Widespread use of a small palette of standard components to maximise the scope of structures which could be made from the construction materials once disassembled. Prefabricated units employed wherever possible to minimize potential for connection errors on site.
Identification All building components to be labelled using a standard identification system informing the disassembly contractors of the material and its specifications. Crucial to the success of this is the production of an accurate set of as-built detail drawings and schedules once the construction is complete.
88.
VI. Regulations 89. Part B 90. Part M 93. Part J
Part B Compliance Fire Strategy
The Plant is designed with appropriate provisions for the early warning of fire. Full time members of staff will be trained to supervise evacuations and conduct an effective fire escape of all building users
Fire escape routes The community facilities at The Plant fall under the â&#x20AC;&#x2DC;assembly and recreationâ&#x20AC;&#x2122; category, meaning all spaces have been designed with travel distances no more than 45m to an exit or a fire protected lobby.
Fire protected lobby with 120 minutes fire resistance
Places of special fire hazard, all to be treated as compartments with 120 minutes fire resistance and maximum 18m escape distances. *The recommended escape travel distances will not be feasible in the basement, so a specialist fire consultant will be appointed to reach an engineered solution.
Boiler room containing the backup burner, switched on to deliver hot water supply only in the rare occasions (less than once per year) when the main CHP engines fail. A fireproof curtain will be lowered in these occasions to create a temporary compartment.
89.
Part M Compliance Accessible Design Features
There will be a circulation core at both ends of the building, each to contain a lift with internal dimensions greater than 1.1m x 1.4m and unobstructed manoeuvring space of 1.5m x 1.5m in front.
A single axis of circulation will connect all areas within the building, facilitating convenient orientation and wayâ&#x20AC;&#x2018;finding for building users. Circulation routes are a minimum of 1.8m wide, allowing wheelchairs to pass smoothly in all locations.
The monolithic heat tanks and exhaust flues will serve as a beacon to help visitors identify the building from afar.
Vehicular access
Once the building is in sight, the change in external floor finish and the timber boxing around each door will clearly identify the primary points of entry into the plant, hall and canteen.
At 30m wide, Riverside Yard has space to accommodate the turning circle of delivery and emergency service vehicles, minimising the need for reversing.
A series of 5m ramps at a 1:15 gradient, split by 2.5m landings, will run along the side of the building to give disabled visitors a route between the piazza and the riverside path. A 1:30 slope runs along the park for those who find the 1:15 too strenuous.
Deliveries and emergency services will access the site from the city centre end and will be able to move along Riverside Walk to reach the cafĂŠ entrance and the park beyond.
Donâ&#x20AC;&#x2122;t Forget About Me! Designing for Little People
91.
92.
Part J Compliance
Combustion Appliances and Fuel Storage Systems The Plant will expose as much of the technical equipment as possible to visitors and passers by, making the usually abstract process of energy generation more accessible to those using the building. Flues carrying gases around the equipment will be treated with a colour finish according to their role, and will be visible both inside and outside the building. Key components from within the various plant machines will be shown in isolation in the undercroft exhibition space to help visitors understand the stages of the process before they enter the boiler room observation space.
1. All natural gas service and installation pipes will be installed such that the fire resistance of the building is unimpaired. 2. Emergency control valves shall be located external to the building to preserve control over the supply in the case of a fire. 3. An adequate supply of fresh air will be delivered to the boilers, first passing through a heat exchanger unit to reach a higher temperature and better facilitate complete combustion. 4. Appropriate provision shall be made to detect and give warning of the release of carbon monoxide 5. Exhaust gases will be passed through a heat recovery unit after emerging from the boiler, increasing the amount of energy able to be derived from each unit of fuel. 6. Catalytic converters and other such plant equipment will be used to treat the exhaust gases and minimize the amount of harmful pollutants being released into the atmosphere. 7. The flues and heat tanks exposed to the public will be heavily insulated to reduce the risk of fire and to avoid burns to visitors. 8. Exhaust gases will be released sufficiently far away from areas open to the public such that they do not pose a risk to the health of visitors.
93.
Safe Operation
Protecting the Basement from Water
1 in 100 year flood level
Provision 1 - Waterproof Tanking
Provision 2 - Waterproof Enclosure
Provision 3 - Automatic Shutdown
A bituminous waterproof membrane will be chemically bonded to the underside of the concrete floor slabs, and run continuously around the outside face of the retaining walls, forming a watertight barrier emerging a minimum of 150mm above the lower ground floor, well above the 1 in 100 year flood water level.
Though the flood risk is low, there is a chance of breaks in the retaining wall or defective district heating pipes letting water into the basement. All plant equipment on the basement level will be housed in enclosures which are waterproofed up to 300mm, with service ducts and connections being similarly protected.
The basement level will be equipped with intelligent moisture sensor systems which are able to detect the ingress of water and automatically shut off the machines before any significant damage is done. In these cases the CHP engines will be shut off and all heat in the system will naturally escape through the exhaust flues.
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VII. Reflection 95. Design Evolution 97. Things Iâ&#x20AC;&#x2122;d Change 98. Summary
Design Process Evolution of the Scheme
1. Initial Concept
2. Exposure
3. Levels
Initial design concepts involved using the escaped heat energy from the thermal stores to create a vertical allotment suitable for growing tropical plant species, saving the transport emissions of importing them from overseas. I soon discovered that, unsurprisingly, the thermal stores are designed with very thick insulation so that such heat losses do not occur.
One early concept which endured was the idea of positioning the monolithic heat tanks in view of Newfoundland Way the main road entering Bristol from the north, acting as a beacon of sustainability to attract the attention of thousands each day whilst building Bristolâ&#x20AC;&#x2122;s image as a national leader in clean energy.
Much of the design stage was spent resolving the most effective way of traversing the 3.5m level change across the site, which would need to be as direct as possible to effectively connect St Judes and St Pauls whilst still complying with the maximum gradients set out in Part M of the building regulations.
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4. Earth Sheltering
5. Simplification
6. Acoustics
Given the size of the proposal and the natural slope across the site, it was decided that the park end of the scheme should be recessed into the Earth with its roof acting as an extension of the outdoor space, minimising the proposalâ&#x20AC;&#x2122;s impact the amenity value of Riverside Park for local people.
Once the consideration of detailed design elements began, it became clear that a more simple repeating roof structure would have many advantages over the eye catching but â&#x20AC;&#x2DC;function follows formâ&#x20AC;&#x2122; profile which had been suggested at the interim review stage.
An acoustic wall was added into the engine room when the noise output of the CHP engines was given more consideration. This wall ended up improving the scheme, with the resulting gradient of exposure from safe to dangerous plant creating a more dynamic and exciting journey through the building.
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If There Was More Time... Changes and Additional Features
?
1. Refine Riverside Yard
2. Detailed Substation Design
3. Relocation of Transformers
Although it was outside the scope of the brief, it would have been useful to look more closely at how Broad Plain Youth Club would have been rejuvenated under the Frome Gateway masterplan. Knowing the schedule of accommodation and floor layout would have meant a more specific and responsive approach could have been taken to the design of Riverside Yard, rather than the functional but rather generic design included in the proposal.
If the project was taken further, it would be interesting to develop a vernacular for the series of substations required to house the step down transformers and heat exchangers for any buildings being linked to the CHP network. Though such substations tend to be fenced off eyesores in neglected pockets of green space, the earth sheltering and material palette used at The Plant could be utilised to create a series of integrated satellite pocket parks, all embracing the same language of regeneration.
The spatial requirements of the high voltage transformer only became apparent once the basic programme had already been established. Though there are various strategies in place to ensure the safety of the transformer in all scenarios, it would in reality be more practical to relocate the transformers to an outbuilding on the upper ground floor level (eg at the back of Riverside Yard) where they can be more easily accessed by service vehicles.
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Reflection
I have thoroughly enjoyed the process of designing The Plant, all the way from early research into CHP systems through to the detailed design of the proposed building. The scheme embodies my views on what good architecture should be, working for people and for the planet, both now and in the future. It presents the community with a versatile series of spaces which, owing to their combined flexibility, should be resilient to change and remain useful for generations to come. Whilst serving as an effective platform for community life, the schemeâ&#x20AC;&#x2122;s primary objective is to act as a flagship for a new kind of building typology; one which, if adopted on a national scale, could represent a significant step towards addressing the issue of our time - reducing our carbon footprints to a level which the planet can sustain.
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