1
summary The Central St. Giles case study was the starting point of the investigation regarding strategies of refurbishing the city and improving the quality of life in urban environments and buildings. Clear lessons carried from that study, provided a vehicle for design explorations where concepts that were found to be working on the existing precedent were applied in the design process. In addition, the project focused on creating a future vision of the city, where lifestyle trends and developments in the technology of domestic appliances were reviewed. As a result, a courtyard which functions as “room in the city� is proposed, enclosed by a free running building which houses a mixed office and residential use.
3
PROJECT BRIEF
PRE-DESIGN STUDIES
STRATEGIES
British Museum
Urban Analysis
ord St New Oxf
DENSITY
The plot ratio aimed for will be 5:1 or 4:1 from 20.000m² to 17.000m²
3 Bedroom 25% PROGRAMEE
Residential 60%
2 Bedroom 35% 1 Bedroom 20%
Proposed urban connection
Site
Convent Garden Existing Building
Solar Availability 00
14:
00
0
13:0
12:
Studios 20% Offices 30%
N
Commercial 10% Sun availability in the site in spring equinox at lunchtime
MATERIALS
ENERGY
Low embodied energy materials will be choosen
The building will be free running and 50% of its’ energy consumption from appliances will be offseted
Carving process respecting the passive zone
SHOE BOX
Daylight Simulations
Thermal Simulations Addition of top floors in order to increase density
BUILDING DESIGN
PERFORMANCE Typical summer day
Typical summer night
Typical winter day
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Acknowledgements Rodolfo Pedro Augspach would like to acknowledge the Architectural Association School of Architecture for the bursary he was awarded to attend the A.A. S.E.D. MArch course 2011-2012. Meital Ben Dayan would like to acknowledge the Architectural Association School of Architecture for the bursary she was awarded to attend the A.A. S.E.D. Msc course 2011-2012. The entire team would also like to thank the entire SED teaching staff for their support throughout the course.
Table of Contents
Introduction 07 Overview 08 Lessons from term 1 project 14 Predesign Studies 16 Design Proposal 28 Design Verification 40 Conclusions 58
7
Introduction The project took shape with the help of a process starting with the lessons learnt from the Central St. Giles case study. This was accompanied with the application of tools taught in the graduate programme which provided a vehicle for design explorations. The aim was to achieve design solutions that contribute to quality of living in cities while subsequently embracing the issues of urban morphology, transportation and the built form that focuses on housing and the home-work environments.
The project addressed strategies for refurbishing the city through the contribution of the proposed building and outdoor area to the urban fabric and connections. .
Key objectives of this project:
Bioclimatic techniques for heating, ventilation, cooling and lighting were adopted. In the winter, importance was given to minimise heat loss and allow for solar gain while during the summer the use of high thermal mass with night time cooling was adopted.
- To improve the quality of life and environmental conditions in cities A comfortable outdoor space was created, a ‘Room in the City’, a place to stay in that could accommodate different activities. In addition a new urban connection was established aimed to revive less successful urban areas.
- To develop the architecture of sustainable environmental design
The facade design is responsive to the different orientations and to the internal spaces requirements and they incorporate means for occupants adaptive opportunities. The postion of the different functions was chosen according to their requirements. Lastly, the overall form of the building is responding to the site conditions according to the pre design studies that were carried out and the objectives set in the brief.
Adaptive opportunities for occupants thermal and visual comfort were provided through manual control of shutters, shading devices and all openable windows.
- To achieve independence from nonrenewable sources
Photovoltaics positioned on the roof of the building are able to offset the energy consumption of most of the residential units and part of the offices.
Central St Giles project that was studied in the first term was used as a precedent and the functional and environmental improvements from the lessons learnt have been illustrated.
The adaptation to changes in occupancy and outdoor climate and simulations for different predicted conditions were simulated in order to establish the robustness of the design as shown in the design verification chapter. Renewal energy resources were used to cover the residual loads for all the residential units. Finally the use of materials for this proposal was selected to reflect and retain the characteristics of the neighbourhood while giving importance to the use of lower embodied energy materials.
- To demonstrate transparency in the process as well as the outcome of design
The inputs used and assumptions that the design is based on are clearly described throughout the report.
9
1 – OVERVIEW
Other Council’s Camden Council
Figure 1: London Region with its respective council boundaries
Town Centre’s Neighbourhood Centres Central London Frontages Growth Areas Tottenham Court Road Growth Areas
Figure 2: The growth areas as per the Camden concil’s strategy
The Term 1 project, Central St. Giles, lies within the Camden Borough of London. For this term’s project, the team aimed to choose a site within the vicinity of Central St. Giles in order to have the opportunity to work on a proposal in the same context and implement the lessons learned from the previous term. Camden Borough is situated in central London (figure 1). And hence it plays a prominent role in London’s future growth. This is indicated in the proposed London Plan. For the years 2010-2026, the council predicts an increase in the residents population of 18% (approximately 36,000 inhabitants). In order to meet the increasing population requirements, Camden aims to provide 815 new homes per year as part of its plan. The council identified five growth areas for intensification (figure 2). Within them 60% of the future residential demand is to be met. As part of the objectives for the development of the growth areas the council aims to minimise social polarisation and secure a mixed and inclusive community by providing a range of housing in different sizes. The chosen site for this project (21 New Oxford St) is a part of the same growth area as Central St Giles; Tottenham Court Road Growth area (figure 3) and is situated in a strategic location within walking distance from cultural, retail and leisure centres as shown in figure 3. Figure 3: The Tottenham Court Road growth area amongst prominent and thriving destinations. 10
Weather Data
NEW OXFORD STREET
The weather data used for the design proposal was collected from Kensinsgton & Chelsea weather station located 5.7km from the site as shown in Figure 3. The readings for the field measurements in respect to the wind were corroborated with data obtained from the weather underground website (http://www. wunderground.com). For all other simulations a weather file was generated with Meteonorm 6.1 using the weather data from the Kensington & Chelsea weather station in London which has readings for a 10 year period ranging from 1996 to 2005. Figure 4, shows the mean temperature for this weather data along with the global radiation classified into direct and diffused radiation.
KENSINGTON / CHELSEA WEATHER STATION
This will be the source of data for all future references to weather data, unless otherwise noted.
Comfort Model For the purpose of this research the comfort bands and zones are calculated using the following two models: Figure 3: Image Showing the relation between the site and the Kensington / Chelsea Weather Station in London Source: After Google Earth
1 - De Dear’s equation, taught in the MArch/Msc programme of Environmental Energy Studies at the Architectural Association. The equation is here presented: Tn = 17.8 + 0.31 Tm Where, Tn = Comfort temperature as per De Dear Tm = Monthly mean temperature A comfort band is then plotted using a +- 2.5 K difference for 90 per cent acceptability and a +- 3.5 K difference for 80 per cent acceptability. 2 - the EN15251:2007 equation, taught in the MArch/Msc programme of Environmental Energy Studies at the Architectural Association. The equation is here presented: Tn = 18.8 + 0.33 Trm
Global Solar Radiation Direct Solar Radiation Figure 4: Graph Showing the monthly diurnal temperature and solar radiation averages, classified into direct, diffused and global radiation. Source : After Kensington and Chelsea weather station data in London generated with Weather tool 2011
Where, Trm = weighted running mean of the daily external temperature A comfort band is then plotted using a +- 3 K difference for a normal level of expectation for new buildings and renovations for 90 per cent acceptability. 11
1 – OVERVIEW
rd St New Oxfo
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St
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Figure 5: Satellite view of the chosen site Source: Googlearth Listed Buildings
Location
Conservation Areas
British Museum
Site
The site, 21 New Oxford Street, is geographically located in a central part of London and has a Latitude of 51°31’00.53”N and a Longitude of 0°07’27.93”W (figure 5). At present it is occupied by an abandoned building and is bounded by New Oxford Street, Museum Street, High Holborn and Dunn’s Passage. New Oxford Street and High Holborn streets are busy vehicular routes. Museum Street has a low volume of cars and pedestrian and Dunn’s passage is a pedestrian alley which is closed for access at both ends.
Camden Boundary
Council
Lincoln’s Inn Fields
Crossrail Station
The site is part of a small pocket of buildings that are not in a conservation area, and are not listed, as shown in figure 6. The building is positioned in close proximity to numerous prominent destinations as the British Museum, Seven Dials, Covent Garden, Oxford St shopping area, Cross rail station and Holborn (figure 7).
Covent Garden Seven Dials
In terms of views from the north the site is in a potential landmark position in respect of the view south from the British Museum. From the east the site lies in a prominent position with respect to existing views of Centre point and from the west the site can be seen as a backdrop to Centrepoint. Figure 6: Plan showing the listed buildings and conservation areas. 12
Figure 7: Plan showing the pedestrian routes to prominent destinations.
Figure 8: Street level view.
Figure 9: Views of the building from street level at different corners of the street.
Existing Building The existing building is a brutalist style building that was constructed by the old Ministry of Works between 1961 and 1969. It functioned as a sorting office until the early 1990s when it’s operation was stopped and the building was abandoned. Its current neglected appearance diminishes the public realm and the adjacent Bloomsbury Conservation area (Camden Planning Brief, 2004). The building plot ratio is 7.2:1 with floor area of 29,000 m2 and site area of 4000 m2 (figures 8, 9 and 10) Figure 10: Views from inside the building. 13
1 – OVERVIEW
14
Figure 11: Diagram of the Brief 15
2 – LESSONS FROM TERM 1 PROJECT
Figure 12: Views of the Central St. Giles development. Source: Renzo Piano Building Workshop
The project that was studied by the team in Term 1 was Central St Giles development by Renzo Piano Building Workshop. As mentioned in the introduction, this study was used as a base for the proposed design in this report and the team aimed to implement the following lessons that were learned as part of the design. Allow for transient activity connecting the neighbouring destinations Central St Giles form was designed according to its urban setting. The five public access points to the courtyard are oriented in relation to the urban context and create views through the site and crossing paths from the different prominent destinations adjacent to the site. In this way St Giles courtyard acts as a connection between formally disconnected areas (figure 13). Maintain visual permeability at the ground level
Figure 14: Visual permeability from within the courtyard.
The ground floor in Central St Giles is 6m height and almost fully glazed. This design creates visual permeability between the square and the surrounding streets and even from one side of the building to the other (figure 14). The visual connection encourage activity within the square as well as pedestrian crossing the site. Maximise solar access in the courtyard Although St Giles courtyard is relatively small and the building is high. Through the positioning of opening in the building form and lower height of the southern wing of the building, good solar availability is achieved in the courtyard during lunchtime. This contributes to achieving comfortable conditions in the courtyard and creates an attractive outdoor space (figure 15). Figure 13: Pedestrain access from the St. Giles to neighbouring destinations. Source: Renzo Piano Building Workshop 16
Figure 15: Solar access into the courtyard during lunch time.
Lux Protect the courtyard from high wind speeds Through the field studies that were carried out, comfort analysis and simulations it was observed that wind speed has a very significant effect on the comfort in the square. It was found that with low wind speed of 0.5 to 1 m/s comfortable conditions could be achieved throughout most of the year in the square. Figure 16 shows how the courtyard is protected from the prevailing winds. Maximise light with higher reflectance within the courtyard The use of a finish with a high reflectance in the courtyard (light grey terracotta tiles) created an even distribution of light and good lighting levels in the courtyard. A simulation of the light level using Radiance as shown in figure 19 demonstrates it. Achieve good solar control on the south facing elevations Figure 16: CFD simulation for southwest wind illustrating lower wind speeds in the courtyard. Source: Ecotect Analysis 2011 + Winair
Figure 19: Illumination levels in the courtyard due to the light colour facades.
During the studies of the apartment it became apparent that the south oriented apartment overheat and requires and that overhang shading would be very efficient in preventing solar gains in the summer when they are not wanted as shown in figure 17. Attain an adequate window to floor ratio The apartments in St Giles development have a high window to floor ratio resulting in higher heat loss and an uneven distribution of daylight. Through a series of simulation a lower ratio was established. Figure 18 shows the north apartment daylight distribution with 28% window to floor ratio. Allow for ventilation in the corridor areas of the residential block As part of the studies that were undertaken the team observed a significant overheating in the circulation corridor between the apartments. This occurred due to the corridor being surrounded by apartments, good air tightness of the building and internal gains in the corridor from lighting and the central heating system with no ventilation. The team concluded that ventilation is required in order to achieve comfortable conditions. Figure 20 shows is a schematic section showing the overheating of the corridor. Ventilation strategies should take into account the disturbing noise levels The apartments overlook vehicular streets with high noise levels. As a result it created uncomfortable conditions for the occupants and a conflict when opening the windows for natural ventilation requirement.
Figure 17: Solar protection from South. Source: Ecotect Analysis 2011 + Radiance
Figure 18: Daylight factors for an appropriate galzing ratio. Source: Ecotect Analysis 2011 + Radiance Figure 20: Corridors unventilated. 17
3 – PREDESIGN STUDIES
British Museum
N um
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ord St New Oxf
Freemason Square
Urban Strategy
Seven Dials ur
Dr yL
As described in the overview, the site is located in a very central area of London within walking distance to a large number of attractions as Seven Dials, the Covent Garden area, the British Museum, Bloomsbury, Oxford St and Holborn, having access to touristic, leisure, cultural and retail centres.
n
Once the site was selected the team conducted visits to the site and studied the urban context through maps, analysis, studying of Camden Planning Brief for the site and the Camden Plan for the Tottenham Court Road Growth Area. Figure 21: Urban context
Figure 22: Pedestrian activity
Figure 23: View from the British Museum
Figure 24: Museum St. South part
However as a result of the urban study and analysis it became apparent that despite this very central location the site itself has very little pedestrian activity and is in fact a clear barrier between the successful pedestrian areas of Bloomsbury and Covent Garden. As shown in figures 21, 22 and 23, Museum St to the north of the site is characterised by small shops and cafes with people walking and sitting outside. This activity was observed to take place even in cold weather conditions in the winter. Similarly the southern part of Drury Lane to the south of the site has small shops and cafes as well as pedestrian activity. The Square in front of the Freemasons Hall at the south part of Drury Lane was observed in all the visits the team made, and was deemed as particularly successful in terms of pedestrian activity with people sitting outside even in January. In contrast, south Museum St adjacent to the site has almost no pedestrian activity. As shown in figures 24 and 25 It is characterised by blocked facades of buildings that are not in use, such as a parking building and a hotel with a closed facade to the street. In addition New Oxford St and High Holborn St are forming an urban barrier with high volume of cars and complicated pedestrian crossings. 18
Figure 25: Museum St. South part
um
se Mu
Visual connections were identified as a strong potential of the site and were used to create an urban link between Bloomsbury and Covent Garden through a new outdoor space.
St
ord St New Oxf
Site Designated Growth Area Proposed urban connection View lines ur
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Active pedestrian areas Inactive pedestrian areas
Figure 26: visual connections
Visual Connection There is no active pedestrian link between the British Museum and the site. There is also no connection between the Covent Garden area (through Drury Lane) and the site. Nevertheless, there are very strong visual connections between the three as shown in figure 26. There is a clear view from the northwest corner of the site towards the British museum and the southwest corner of the site has also a good visual connection towards Drury Lane (figures 26 and 27). These visual connections were identified as a strong potential of the site and one that can be used to create an urban link between Bloomsbury and Covent Garden areas through a new outdoor space. Figure 26 shows the proposed connection and the square. To complement this urban strategy, it is proposed to turn Museum street to a pedestrian street (it is partially pedestrian at present as shown in figure 27) simplifying the pedestrian crossings in New Oxford St and High Holborn St. Figure 27: Museum Street. North part
Figure 28: Connection between the British Museum and the site 19
3 – PREDESIGN STUDIES
Cloudy
Outdoor Studies - Comfort As established in the project brief (see figure 1) a “room in the city” is a goal to be achieved by the design, in order to promote outdoor life. The team has decided on giving as much importance to the outdoors as to the indoors instead of having the former be just neglected or resultant spaces. This resulted in the courtyard being designed on parallel with the building shape. Therefore, a constant compromise had been maintained as the courtyard was carved out of the existing building. To do this procedure, guidelines had to be established.
Partly Cloudy
January
February
March
April
May
June
January
February
March
April
May
June
50 40 30 20
Sunny
10
%
60 ° 50 °
London’s oceanic climate (see Climate chapter) is not too harsh, so encouraging the use of outdoor spaces is something achievable. With the Court at Central St. Giles as a starting point (see lessons learnt from St. Giles), a few guidelines have been established:
40 ° 30 ° 20 ° 10 °
- Wind protection should be guaranteed - Solar access has to be permitted
This is the case when a sedentary activity is encouraged, such as eating, or meeting outdoors. Therefore, the first thing to be done is establish the potential of the different days on the users of the space. The first graph in figure 29 shows the sky conditions, if solar access is to be permitted, the number of sunny days in relation to overcast days has to be known, as this is a matter that escapes the grasp of the design. The first thing noted by the team was how the second half of the year has a greater tendency for sunny days than the first half, whilst the partly cloudy conditions remain around 40 % of the time through most of the year. On a second graph, in figure 30, the solar altitude (profile angle) at 13:00 hours has been plotted in order to know the maximum obstruction angle for each month. The hour has been chosen because the activity to be encouraged is lunch. The Azimuth angle for that hour is from 190° to 210°, as shown in figure 33, depending on the day of the year. Naturally, given that London is on the northern Hemisphere, the sun is higher towards the middle of the year, but due to it’s high latitude of 51°, in the winter months it gets to as low as 15° at 13:00 hours. Overlaying these two graphs together results in considerable predesign knowledge, for instance, on the first graph it shows that November has a predominancy of sunny days over cloudy days, yet, the solar angle is so low that it might not be too feasible to allow for solar access.
400 300 Direct Solar Radiation Available Diffused Solar Radiation
200 100
W/m²
35 Comfort Band High Limit
30 25
Neutral Temperature Comfort Band Low Limit P.E.T. Sunny Areas
20 15 10 5 0
P.E.T. Shaded Areas
-5
°C 20
July
August
September
October
November
December 50 40 The next step was to quantify the possibilities or advantages of the solar access. For this purpose, the diffused and direct solar radiation have been plotted in a third graph in figure 31, accounting for the total global radiation. Diffused solar radiation is the one that is not radiated directly from the sun, but rather from the dome itself. Therefore, to calculate the available diffused solar radiation in a plot, the height of the surrounding buildings or building has to be known, resulting in a sky view mask. Because this graph is meant as a predesign tool, the sky mask for the Court at Central St. Giles has been used (figure 34). As a result, the diffused solar radiation shown in this graph is that incident, which falls in the piazza, at 13:00 hours, calculated with ecotect.
30 20 10
% Figure 29: Sky conditions at 13:00 hrs during the different months Source: After Satel-light 60 ° 50 ° 40 ° 30 ° 20 ° 10 ° Figure 30: Solar altitude at 13:00 hrs during the different months Source: After Ecotect
Figure 33: Azimuth for latitute of 51° Source: After Ecotect
To determine the effect of the solar radiation on the actual comfort of the occupiers the Physiological estimated temperature has been calculated (P.E.T.) using Rayman, for an obstructed spot and an unobstructed one at 13:00 hours throughout the year shown here in (figure 32). This provides an idea of how much a person’s comfort is influenced by the sun, along the different months of the year. Because one of the premises of the team is to guarantee wind protection, a constant wind speed of 0.5 m/s has been maintained for the calculation. Afterwards, a comfort band has been calculated using De Dear’s equation for indoor comfort, in order to draw a comparison. This band is for 80% acceptability (5k) plus an adjustment in width given that people outdoors enjoy a substantial range of possibilities for adaptive comfort, such as having a cold or hot drink, moving from a shaded or protected area into a sunny or non protected area, or even, move indoors.
400 300 200 100
W/m² Figure 31: Solar Radiation during the different months divided in incident diffused and available direct Source: After Ecotect 35 30 25 20 15 10 5 0 -5 July
August
September
Figure 34: Sky view mask for St. Giles Court (Source: Ecotect)
The vertical reading of all these graphs can therefore provide for an assessment of how likely it is to use an outdoor space on a given month of the year. As an example, it has been established that November has more sunny days than overcast, but it was unlikely for the sun to be unobstructed at this month because of it’s low solar altitude on regards to the plot. When looking at the final graph (figure xx) it becomes clear that the effort of allowing a 20° sun to penetrate is just not worth it, because although there are more sunny days available, that solar radiation is not enough to raise a subjects perception of temperature above 14°C. This means that even when solar access and wind protections are provided for, there are still a few months which have low dry bulb temperatures which make it impossible to enjoy a meal outdoors.
Height: 1.75 m. Weight: 75 kg. The conclusion of the overlay of all these graphs is that the maximum Age: 30 obstructed angle should be 30°. This will allow for solar access in the months of Gender: male March to October, which have the days with the strongest likelihood of providing Activity: 80 W the external conditions required for outdoor comfort, and because the solar Clo: 0.6,1.2,2.2 altitude angle of 30° is considered as high enough. Air Velocity: 0.5 m/s
October November December °C Figure 32: Yeary P.E.T. for sunny and shadded areas Source: After Rayman 21
3 – PREDESIGN STUDIES
00
00 12:
0 13:0
14:
Together with sun availability, protection from the wind was identified as a main factor in the London climate in order to achieve comfortable conditions outdoors for a longer span of time.
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Outdoor Studies - Sun availability
Figure 35: Sun availability in the site in spring equinox at lunchtime
Having the importance of sun availability established in the comfort analysis (see “Outdoor studies - comfort”) and as part of the lessons learned from the Term 1 project investigation. It was identified that achieving comfortable conditions during lunchtime is particularly important since it is the time when people can be encouraged to be outdoors. With the high volume of offices in the area and in the proposed building as well as the touristic activity together with the residents, lunchtime has a large potential for successful outdoor activity provided comfortable conditions are achieved.
March 21 9:00
March 21 13:00
March 21 16:00
June 21 9:00
June 21 13:00
June 21 16:00
Dec 21 9:00
Dec 21 13:00
Dec 21 15:00
Preliminary assessment of the sun available in the site was carried out using Ecotect. Figure 35 shows the shadow range in the spring equinox between 12.00pm and 2.00 pm. It can be seen that during this time, the sun is unobstructed for most of the site area. Figure 36 shows the sunpath in the site throughout the year at 9.00 am, 1.00 pm and 4.00 pm. These hours were chosen in relation to the predicted future activity in the square. For a mixed used development of residential, offices and retail, the start of the working day (9.00am) and the afternoon (4.00 pm) were identified as important times in addition to lunchtime (13.00) as discussed above. It can be seen that sun is available in the square throughout most of the year except for the winter months. The main overshadowing is created by the hotel building to the south west.
Figure 36: Sun availability in the site throughout the year without the existing building 22
New Oxford
St
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tel
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Outdoor Studies - Wind Analysis
t
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Figure 37: Air velocity spot measurements on Jan 15 between 12.00 and 12.30 pm
Together with sun availability, protection from the wind was identified as a main factor in the London climate in order to achieve comfortable conditions outdoors for a longer span of time. Figure 39: North wind Simulation using C.F.D Source: Ecotect Analysis 2011 + Winair
The team carried out field studies and measured the air velocity in the site on Jan 15 between 12.00 and 12.30 pm. During this time the wind directions were North and North-North West at 6 m/s according to weather underground data for Kensington weather station. Figure 37 shows the measurement results. High air velocities were measured in New Oxford St and High Holborn St. In addition turbulences were observed in Museum St as a result of downdraft wind from the Hotel building. As the prevailing wind in London is from the southwest a computer fluid dynamic simulation was carried out using Ecotect Analysys + Winair for Southwest wind (figure 38). It can be seen that with the existing building, Museum St is protected from the wind. The team estimated that this is due to the location of the hotel and parking building to the west of the site and the south elevation of the existing building blocking the wind from this direction. In order to verify the results of the simulation, simulations for North and North - Northwest winds were carried out as well and compared to the field studies measurements. (Figures 39 and 40). It can be seen that the simulations are showing similar results to the field studies. The team concluded that it is important to keep the protection from the south in the proposed building shape. A second conclusion is that some protection from downdraft winds caused by the hotel building should be provided as part of the proposal.
Figure 38: South - West wind Simulation using C.F.D Source: Ecotect Analysis 2011 + Winair
Figure 40: North - West wind Simulation using C.F.D Source: Ecotect Analysis 2011 + Winair 23
3 – PREDESIGN STUDIES
The Existing Building The existing building was completed in 1961 and was used as the UK mail sorting Office. It is vacant and boarded since the early 1990’s. (Camden Planning Brief, 2004). As shown in figure 41 the building has a deep plan and it includes eight floors and a basement. The first four floors have a floor to floor height of approximately 6 m with some mezzanine areas and the upper four floors are 2.8m high. The building has a concrete structure and single glazing curtain wall facade. Between the summer and February 2012 an alternative theatre group used the building as a theatre venue. Thanks to their collaboration the team was able to access the building and evaluate the building from the inside (figures 42, 43). During this visit the team was able to appreciate the 6m height spaces and their potential as well as the general state of the building. In addition the team examined former planning applications that were submitted to the Camden Council. All three were for a change of use proposing to retain the building (submitted 1995, 1998, 2000).
Figure 41: Existing building structure
The Camden Planning brief also suggests it as a viable option. Based on these and as the building contains a large amount of concrete the team aimed to retain as much as possible from the existing building while creating a naturally ventilated and lit building and a quality outdoor space. Figure 42: Existing building internal view 24
Figure 43: Existing building internal view
3rd Floor
Indicative Passive Zone Existing floor
2nd Floor
Proposed mezzanine floor
1st Floor
Ground Floor
Figure 44: Indicative passive zones shown on existing building section and proposed mezzanine floors
Passive zones As the existing building has a deep plan of approximately 60m, a preliminary study of the potential to naturally ventilate and use of daylight was carried out. According to Baker (Baker, Et Al, 2002) a ratio of 1:2 between the top of the window height and the depth of the floor will allow for a good illumination by daylight as a rule of thumb. This ratio will also indicatively allow for good natural single sided ventilation (Baker, 2007). Using this ratio the existing buildings floor and section were analysed. Two options were examined: the original 5.8m height floors and a mezzanine division of 2.8 m height. Figures 44 and 45 show the size of the indicative passive zones in plan and section. Figure 45: Indicative passive zones shown on existing building ground floor plan 25
3 – PREDESIGN STUDIES
Thermal Simulations - Residential Units The thermal simulations that formed part of the predesign studies for residential units aimed to define the amount of glazing area for each facade according to the orientation. They also served to verify the depth of the plan previously defined by the passive zone studies in regards to the natural ventilation strategy and daylighting. The first step was modelling in TAS a “shoe box” apartment using the 5.80m floor to ceiling height of the existing building as shown in figure 45. The “shoe box” is meant to represent a typical typology of a 45.00m ² one bedroom apartment, with the kitchen and living room integrated in a unique space in the lower floor and the bedroom located in the mezzanine (see one bedroom typology). In order to achieve a better accuracy in the results, the model was divided in 2 zones, one for the upper floor and another one for the lower floor where different internal conditions were set. The adjacent apartments at the same floor as well as the one above and below were assumed to have the same internal conditions as the apartment that was investigated and therefore were not zoned.
Passivhaus Institute Internal Gains Scenarios (Appliances + Lighting):
Internal gains Considered in the Shoe Box Simulations:
Figure 45: TAS thermal simulation model with colours indicating the different zones (Shoe box).
Kitchen/Living room: 4.0 W/m² Bedroom: 2.1 W/m²
The “shoe box” was initially tested for the recommended window to floor ratio of 25% for the south orientation and 15% for east, north and west (Yannas, 1994). The results showed that the apartment in all the orientations could easily perform as free-running in the winter and still provide comfortable conditions for its occupant, with temperatures most of the time close to the upper level of the comfort band. This way the team realized that the improvements in the current materials, insulations and overall air tightness could allow an increase in the glazing area of the apartments in order to provide for better views and daylight conditions.
1. The St Giles apartment is located at the corner of the block having therefore larger exposed wall area (gross area: 41m² against 26 m² of the shoe box) and therefore higher heat losses. 26
Constructions:
Windows: Glass: Low-emissivity double glazing with a solar transmittance in the vicinity of 0.70 and U-value of 1.77 W/m2K. Glass + Night Shutter(Wood layer 40mm thickness): U-Value 1.0 W/m2K Frames: U-Value 2.2 W/m2K Exposed Walls: U-Value 0.25 W/m2K
Infiltration rate: 0.20 ACH Occupancy Hours: Weekdays: 19:00 - 09:00 Weekend: 19:00 - 12:00
Fresh air supply: 30m ³/hour/Person Thermostat: 20 °C for Living and bedroom 9 hours/day. Setback Value: 18 °C
Figure 46: Daylight factor simulation for a shoe box with 45 ° obstruction angle. Source: Radiance,
Heating Loads Kwh/m ²/year
The next simulation was run only for the north orientation which receives less incidence of solar radiation along the year, therefore being the most challenging scenario to achieve independence of conventional space heating. The window to floor ratio tested was 30%, which is the same as the one proposed by the group for the improvements in the north facing apartment of Central St. Giles. A thermostat was set to 20 °C during 8 hours/day with a setback value of 18 °C. The result shows that the energy consumption for space heating is around 1 kwh/m ²/year which was considered a fairly low value. Next, the results were compared to a one bedroom apartment analysed in the Central St. Giles case study (figure 49), which has the same floor area, glazing area and occupancy patterns. The constructions and internal conditions were changed in order to be the same as the “shoe box”. In this case the heating load was 4 Kwh/m ²/year. This fact drew the team’s attention, and a more rigorous analysis of the plan configuration of both residential typologies led to 2 conclusions that explained the 400% heating load difference among the two apartments:
Figure 48: Shoe Box Dimensions.
6 5 4 3 2 1 30%
40%
50%
Window to Floor Ratio North Orientation Apartment
Figure 47: Annual heating loads according to the different WFR (north facing shoe box).
Figure 49: St. Giles North Apartment - TAS model
°C
W/m ² 2. Lower temperatures and higher heating loads were found in St. Giles apartment bedroom when compared to the living room( average of 2°C lower). This was also confirmed by the data loggers’ measurements. On the other hand, apart from decimals variations the temperature in both zones of the shoe box remained the same under free running conditions. This shows that the plan layout of the double height typology, where the bedroom has no exposed walls and is located right above the kitchen area, can be beneficial in terms of reducing the heat loss, by taking advantage of the heat gains generated by the kitchen and living room appliances. From this lesson the team also learned that apartments located in the corners of the building block, with more area of exposed wall, must have a lower window to floor ratio in order to achieve a better energy performance.
Figure 50: TAS simulation for the north facing shoe box in a typical winter week (04/01 - 10/01). Free Running
°C
W/m ²
In order to define a threshold, other simulations for higher window to floor ratios were also run for the north facing orientation. As seen in the figure 47, the results show that above the 30% ratio, the annual heating load increases considerably reaching 5 Kwh/m ²/year when the ratio is 50%. Since the goal is to do away with conventional space heating, and having verified trough radiance that a 30% window to floor ratio can provide good provision of daylighting for habitable rooms (figure 46), it was considered a reasonable threshold to be set. Taking into account the fact that the heating loads are lower for other orientations which are more exposed to direct solar radiation, the team established the same ratio (30%) as a threshold also for east, west and south facing units in order to achieve completely free running apartments. The south orientation which has the best energy balance could still have larger glazing areas without compromising the performance of the apartments, however excessive glazing areas could generate other issues to solve such as: privacy, glare, and a requirement for larger amounts of shading devices. Figure 50 shows the temperatures in the north facing “shoe box” bedroom, under free running conditions in a typical week of January which is the coldest month. It is possible to realize that the temperatures during all the hours are within the comfort band for 90% acceptability, resulting from the EN 15251 equation. This way it is clear that having the thermostat set to 18°C (24hs) the annual heating loads would be 0. For the summer simulations, a south facing orientation was chosen to represent the worst scenario, since it is the most exposed to direct solar radiation. The first step of this simulation was to use overhangs as solar protection and to provide ventilation during the low occupancy hours (09:00 – 19:00) in order to avoid the noise. As seen in the figure 51 this ventilation strategy is enough to keep the temperatures in the comfort zone in a typical week in August which is the hottest month. This way it is possible to assume that this strategy works well for the entire cooling season. Bearing security issues in mind, the windows were only tilted (0.3 aperture factor).
Figure 51: TAS simulation for the south facing shoe box in a typical summer week (09/08 - 15/08). Free Running 27
5.8m
3 – PREDESIGN STUDIES
m
8m
10
12m Figure 52: Daylight Factor Analysis.
Figure 54: North Facing Shoe Box TAS model.
Thermal Simulations - Offices The pre design studies for the offices had the purpose of defining the best orientation and location for the working environments considering the existing building structure that would be refurbished. The depth of the plan in regards to daylighting and the ventilation strategy was also considered as relevant factors as well as the window design. The analyses process started defining a “shoe box” using the 5.8 m floor to ceiling height of the existing building which would have only one exposed wall and this wall apart from the 900mm sill, would be fully glazed in order to maximize daylight. The daylight maximization is desirable since the first floor of the existing building has an obstruction angle of 45 °. The figure 52 shows daylight factor simulations for a overcast sky with 6000 lux since these external light levels are exceeded for 80% of the working hours in London( Randall,T 2006). In this case an average of 5% daylight factor is enough to provide internal daylight levels of at least 300 lux for most of the working year (CIBSE Daylighting Design and Window). It is possible to realize through the simulations that large window panes are creating good conditions of daylight in the first 8 meters of the room, being a good area for placing the working stations. On the other hand, the last 4 meters have daylight factor levels between 2% and 3%, which will be more appropriate for transitional areas or other functions that do not require such high levels.
W Figure 53: Office Gains in a Typical January Day (North Orientation) Internal gains considered in the Shoe Box simulation: Appliances: 16 W/m ² Lights: 11,5 W/m ² Occupants: 10 W/m ² source: ASHRAE
Infiltration rate: 0,20 ACH Fresh air supply: 30m ³/hour/Person Occupancy: 08:00 - 18:00
28
Figure 55: South Facing Shoe Box TAS model.
°C
W/m ²
Figure 56: TAS simulation for the north facing shoe box in a typical winter week (04/01 - 10/01). Free Running
°C
Figure 57: TAS simulation for the south facing shoe box in a typical summer week (09/08 - 15/08). Free Running
W/m ²
The thermal simulations conducted for a typical week of January took into account the internal heat gains recommended by ASHRAE, and just the minimum provision of fresh air required. The constructions are the same specified previously in the residential unit simulations. The shoe box was oriented due north (figure 54), for the purpose of verifying how the offices would perform under free running conditions with very low solar gains. The results here presented in the figure 56, shows that even with such a large glazing area, the high internal gains due to appliances, lights and occupants (figure 53) are helping to create good internal temperature conditions within the defined comfort band, eliminating the necessity of space heating. Another simulation was run for the same shoe box facing due south. The results show that in the same week, in a less cloudy day the effect of direct solar radiation would raise the temperatures above the comfort band (see appendix). This could easily be controlled by increasing the ventilation; however the team concluded that in this case the solar gains are not useful and could be better for the residential units. This way one can also conclude that offices can be obstructed without compromising their heating energy performance. For the summer the single sided ventilation was the only strategy tested in the thermal simulations, considering that if efficiency can be achieved with this method, then the offices would perform even better in a cross ventilation scenario. The shoe box was orientated due south and overhangs were used in order to provide a proper solar control, as shown in the figure 55. The problem of noise was one of the main concerns in regards to the ventilation, since the building site is located in a central area of London. This way the first strategy was to open the first two levels of windows (up to the height of 2,1m) for an aperture factor of 0.3, during the non-occupancy hours (19:00 – 07:00). The upper windows were not open for being considered of difficult access and control for the occupants. The existing concrete slab of the building was exposed in order to couple the thermal mass with the occupied space. As seen in the figure 57 this strategy alone was enough for keeping the temperature in the comfort zone for all the days in a typical week of the hottest month. The figure also shows that the first working hour of the day might have the temperature below the comfort band as a result of the night time cooling. This gave an indication that the windows should have been closed at 6:00, two hours before the people started entering the building.
29
4 – DESIGN PROPOSAL
The aim of the formal design process was to create a building that could be naturally ventilated and lit while retaining as much as possible from the existing structure
Figure 58: Existing building
Design Proposal - Formal exploration The aim of the formal design process was to create a building that could be naturally ventilated and lit while retaining as much as possible from the existing structure as explained in the previous chapter. It was equally important to create a ‘room in the city’, an outdoor space that is comfortable most of the year and that can be used as a place to stay as well as to pass through. Finally it was important that the building and the outdoor space together will enhance the urban fabric and urban connections in this area according to the urban analysis and strategy (as detailed in the predesign studies).
83%
Figure 59: Existing building without the top floors
N
Figure 58 shows the volume of the existing building. The first step was to remove the top floors as shown in figures 59 and 60. The top floors have in the opinion of the team little architectonic potential, their volume is relatively small (17% of the building) and furthermore without removing them it will become difficult to make a significant intervention that will achieve the goals stated above. In the following images, to the left is a bar showing the floor area of the proposed building as a percentage of the original building floor area. The percentage of floor area that will be demolished is shown in red. In response to the urban strategies that were identified, an open outdoor area was created following the view lines from the British Museum (figures 61, 62).
British Museum Existing Building Proposed Square
63%
Figure 61: Carving through view lines upon the British Museum 30
Figure 60: Existing Building. Source: After Google Earth
View lines
Figure 62: Views and connections to the British Museum and Covent Garden
24m N
Sun availability at lunchtime
12m
52%
Figure 63: March 21 Shadow range 12:00-14:00
Figure 64: Passive zone depth
13900 m² 13900 m²
To be demolished Proposed building
29000 m² 15100 m² Existing Building
Figure 63 Option
21500 m²
Figure 66 Option
The location of the cut was determined according to the pre design studies of solar availability in the square (See outdoor studies - Comfort). As shown in figure 63 this shape allows for direct sun in most of the outdoor area during lunchtime in March. Deriving again from the pre design studies this allows for sun availability throughout most of the year. (See appendix for yearly sunpath). The edge of the south wing was cut further to allow for more sun in while the south elevation remained the same length in order to maintain the protection from the wind.
13900 m²
18000 m²
Final Proposal
Figure 65: Density analysis
74%
Figure 66: Top level Addition
62%
Figure 67: Proposed building south elevation. Computer Generated Image
According to the passive zone areas that were established in the pre design studies the building was further carved in order to achieve naturally ventilated and lit spaces (figure 64). The north wing is intended for using the existing 6m floor height and the south wing is intended to combine mezzanine floors of 3m height and therefore it is narrower in plan. This carve was also done in order to create a more enclosed outdoor space but one that is still open and connects with the urban context so different types of outdoor spaces are created within the site allowing for different activities to happen.
As shown in figure 65 the area of the proposed building with this form is 15,100 sq m. This area was considered too low in relation to the density level that the team considered appropriate for such a central urban location and as defined in the design brief. Therefore additional five top floors were added of 3m height and with a narrow plan of 12 m (figure 66). These floors are positioned to the north and therefore do not affect the sun availability in the square. In terms of the urban impact the effect on the building and New Oxford St to the north is minimal as the extension is not significantly higher then the existing building. Furthermore the function of these buildings is offices which are less sensitive to reduction in the direct sun. The impact on the street to the east of the site is more significant (Dunnes passage) as it is very narrow. Therefore as shown in figure 68 the upper floors extension was sloped towards the east and south and the building was carved slightly more on the east side to widen it, creating a place that is more usable and better lit. The sloping responded as well to the scale of the urban block and to the overall urban context and height of adjacent buildings as shown in figure 67 .
Figure 68: Sloping of the top floors 31
4 – DESIGN PROPOSAL
Figure 69: Retail. Ground Floor
Figure 70: Offices. 1st -3rd Floors
Figure 71: Residential. 1st -8th Floors
FORD ST
NEW OX
Overall Building Retail
Programme distribution
8%
Residential Units
1400 m ² 3 Bed 28% 90 m ²
The positioning of the different functions within the scheme (residential, offices and retail) was determined according to their characteristics and requirements as derived from the pre design studies and the brief. The offices with typically higher internal gains and with lower tolerance to glare and direct sun were positioned to the north within the 6m original floor height (figures 70 and 72). The 6m height allows for a higher and larger area of glazing that is beneficial in terms of daylight provision to the office where higher levels of light are required. The high ceiling also provides a larger volume of air which helps with meeting the high fresh air requirements through a lower ventilation rate thus reducing the heat loss through ventilation. A 12m height external space was created to the south of the north wing (figure 71). Due to the provision of this space and the narrow plan of the offices (in relation to the 6m height floors) both cross ventilation and single sided ventilation could be used. This flexibility helps to meet the acoustic requirement, creates an efficient night time ventilation and makes the design robust to future change in occupancy, appliances and climate.
32
Residential
53%
9300 m ² 2 Bed 32% 80 m ²
Residential
Offices
18% 3100 m ²
Offices Cores T NS
External space
R BO
GH
HI
Figure 72: Programme distribution
L HO
N
Circulation & Services
8%
1400 m ²
Basement
13% 2300 m ²
Total
18000 m ²
Figure 73: Floor area distribution
1 Bed
24% 45 m ²
Studio
5% 30 m ²
Figure 74: Residential area distribution
3m
3m
The residential units are located in the south wing, the west part of the north wing and the upper four floors (figure 71). As shown they occupy all of the south facades and most of the west facades. The residential units are characterised by lower internal gains (in comparison to office space), by a wider range of acceptable light levels (a minimum of 1% DF in bedrooms is acceptable in bedrooms according to CIBSE Daylighting and Window Design) and by a higher potential for adaptive opportunities (due to a lower number of occupants per unit and flexibility of moving within the space). Furthermore the direct sun is perceived as an amenity especially in colder days in London. This makes the residential units more suitable to be positioned to the south and west facades. A combination of 6m and 3m height spaces are provided in the apartments using the existing building structure to create quality spaces that are well lit and ventilated in the living areas.
6m
6m
6m
The 12m height external space that is provided in the north wing is located between the offices and residential units and could be accessed by both. As offices and residents have typically inverted occupancy times the external shared space could be used for a larger amount of time. The roof of the south wing (figure 74) also offers an external space that could be accessed by both functions. The ground floor is occupied by retail which has typical higher internal gains. It is recessed and thus protected from the sun. Similarly to the offices, the double height of the existing building allows for higher daylight levels and larger air volume thus reducing the ventilation rate required. The retail functions can use the external spaces in the square for outdoor eating and other activities as well as the prominent position on New Oxford St and High Holborn St.
Figure 75: Building Section
33
4 – DESIGN PROPOSAL
Cafes / Restaurants Retail Residential lobbies New
Office lobby
Oxfo rd S t
Services
Museum St
es Dunn ge passa
Ground Floor As shown in figure 76, the ground floor offers a combination of cafes, restaurants, residential lobbies and the office lobby. New Oxford St and High Holborn St facades were divided to accommodate a relatively high number of shops and cafes, continuing the successful uses that exist in the north part of Museum St and designed to attract people from these streets into the square. This combination has the potential to intensify the activities on these street, the square as well as creating permeability through the ground floor in terms of visual connection and access, as seen in the lessons from St. Giles. The residential lobbies are accessed from the square providing a more protected entrance and the office lobby main access is from New Oxford St to the north. The office lobby could also be accessed through the adjacent cafe providing an opportunity to combine both (this combination was observed by the team in the term one case study project in St Giles). Positioning the security of the offices to the back of the space allows for the lobby to be used as a retail space as well as allowing public access to it and encouraging a mix of activities in a wider range of hours.
n lbor h Ho
Hig
Figure 76: Ground Floor and Landscape design 34
St
Figure 78: Science Museum, London
Landscape Design Figure 79: High Line, NY. Source: http://www.oudolf.com
Figure 82: Summer 12:00. View from the Square towards north.
The landscape design as shown in figures 82 and 83 is a combination of water bodies and vegetation. As references Piet Oudolf designs of High Line garden in New York (figure 78) and the plants used in his design of Pottersfield garden in London (figures 80-81) were looked at. The columns of the existing building in the demolished part are used as lighting at the same height as the ground floor. Deciduous trees located in the square will provide some shaded areas in the summer contributing to a diverse space with different conditions. Permanent benches and tables are scattered in the courtyard to create public spaces for sitting, gathering or eating outdoors.
Figure 80: Pottersfield, London Source: http://www.oudolf.com
Figure 81: Pottersfield, London Source: http://www.oudolf.com
The ground floor and landscape are designed to facilitate the connection and crossing axis between the British Museum and Covent Garden area (as explained in the Urban Strategy chapter), while providing a comfortable place to stay where different activities may happen at different times of the day and year. For example a bookshop on the northeast corner could have workshops and lectures indoors or use the square. Restaurants and cafes can use the outdoor space of the square in different times and people from the offices, residential or adjacent buildings could buy lunch in the grocery shops and use the benches and tables in the square to eat outdoors. Additionally the square and crossing area could accommodate events as food markets or exhibitions, due to its closeness to the British Museum and Museum street. Figure 83: Equinox 12:00. View from the Square towards east. 35
4 – DESIGN PROPOSAL
Figure 84: Circulation Areas
Private Residential Office / Private Residential Affordable Residential
First Level Floor plan (figure 86) The building has four cores, which make up for most of the circulation areas of the floor plan (figure 84). These are interrupted by extending typologies in order to avoid the use of extended corridors. These cores are divided into affordable, social and private housing (figure 85). This subdivision is a consecuence of building requirements and social responses. All the corridors are ventilated, and are coupled with the outdoors, except for the core to the north east. Along the first three double height levels, this core is not ventilated, but it is in an open plan, after these levels, it is used as a residential core, and it is coupled with the outdoors. It is at this level that the garden for the offices is placed, in order to allow for more ventilation strategies, better daylight, and an outdoors area for the workspaces.
36
Figure 85: Different cores divided into
Figure 86: First level floor plan
0
5
10
Figure 88: Mezzanine level, showing double heights.
Offices Three Bedroom Two Bedroom One Bedroom Studio
Mezzanine Level Floor Plan (figure 87) This level is at a middle height between the existing first and second levels. In figure 88 one can see the actual “footprint� of this level overlaid on top of the building shape. This is a testimony that all of the units have a double height at this level, except of course for the studio apartments. This use of the existing floor slabs permits for higher daylight factor values, because the obstructions for this level where above 25%. At a first glance, one can see that density for this level is quite low, but as seen in figure 89, the office part, which is double height makes up for half of the floor plan area. In this same figure one can identify the different typologies used. Figure 87: First mezzanine level floor plan
0
5
10
Figure 89: Typology distribution
37
4 – DESIGN PROPOSAL
Typologies The different units where designed bearing in mind the structural grid of the existing building. The idea is for the units to be as “open as possible” having as few obstructions to the light as possible. This also allows for a “formal” play , by placing all the fixed uses together, creating systems that incorporated bathrooms, kitchens, and in some cases stairs. This creates a space division between “service” and “served” areas, where the later are protagonists of space. By suffering less internal subdivisions these main areas are perceived as bigger, and natural light can be exploited more efficiently
27%
28.8%
All of the typologies have been designed along with their facade closely relating back to their window to floor ratio. This ratio had to be kept below 30% in all cases. The window to floor ratio is given as a percentage along with the facade of each typology. Studio Typology: (figure 90) The kitchen and bathroom system has been placed to one side leaving an open plan unobstructed. The kitchen has been placed close to the window for ventilation and daylight purposes.
One Bedroom typology: (figure 91) This typology breaks down the bathroom, keeping a toilet in the main level, and the bathtub on the upper one, close to the wardrobe. This does not prove to be just functional, but also, light would not be needed for morning showers, and privacy issues are resolved through the use of the different levels. In the north facade of the south wing, this typology varies slightly, extending the living room area by moving the window all the way up to the facade. It has no balcony, because it is north facing, and therefore it would have never had sun. This also reduces further the window to floor ratio. This unit type is also used on the first levels of the north wing, but the bedroom level in that area is one metre deeper.
0
1
2
Figure 90: Studio typology and elevation 38
Figure 91: One bedroom typology and elevation
28.5%
Two Bedroom Typology: (figure 92) This is very much like the studio apartment, keeping the bathroom, kitchen and staircase system together against a wall again creates an open space plan, for better light distribution. It is two modules wide in the lower level, and three on the upper one, therefore these units are placed in groups of two along with a studio apartment, which takes up the two modules at the entrance level. In the facade, one can see how the two units are connected through the master bedroom, and below these two, is the studio apartment.
0
1
2
Figure 92: Two bedroom typology (South Wing), and elevation 39
4 – DESIGN PROPOSAL
27.8%
Two Bedroom Apartment - Single Height: (figure 93) This is the typology used for the upper floors, where the double height was no longer a requirement, because the facades were no longer obstructed. Because it is single height and has two bedrooms, the hallway could not be avoided, so it was placed in the darkest area. The kitchen is again forming a system with the bathroom and is placed closer to the window. The bathtub in master bedroom is placed outside the bathroom in order for it to be lit by natural light.
0
1
2
Figure 93: Two bedroom, single height typology and elevation 40
28%
Three Bedroom Typology: (figure 94) It is basically an extension of the two bedroom typology, which uses the extra module at the entrance level to allocate the third bedroom. The upper level grows into the corridor in a stepped manner, forcing this typology to be placed back to back to each other. Closets and bathrooms are kept to the back in order to give privilege other more important areas.
0
1
2
Figure 94: Three Bedroom typology and elevation 41
5 – DESIGN VERIFICATION
North Wind Direction: Polar wind blows from this direction.
Wind Simulations (figure 95) Wind simulations have been carried out throughout the design process for for the predominant southwest wind. On a later stage, for the design verification, wind simulations have been run for all directions to determine to which was the shape most vulnerable to, as wind, blows from everydirection at any given time.
West Wind Direction: Predominant wind in the Summer time.
In all simulations, the Court at Central St. Giles has also been ploted because it is assumed that it is a fairly well protected area. This enabled the team to draw comparissons between one and the other, in order to understand the magnitude of the turbulence. It is quite complicated to simulate wind simulations in urban areas because a lot of factors come into play. Therefore, this is not a tool to establish wind speeds on any given point when wind blows from a certain direction. However, this effectively shows where wind speeds are more likely to be higher or lower, by simple comparisons. In all wind simulations the scale has remained the same, which means that the gradual darkening of the blue means exactly the same increment in air velocity in all simulations. All wind simulations are for turbulence at 1.5 metres high, and the cell spacing is of 10m. x 10m. x 5 m. (x, y, z).
42
South West Wind Direction: Predominant wind year long.
Looking again on figure xx for the predominant wind direction simulation, it can be read, that there is very low turbulence in the court of Central St. Giles, and the same can be said for the propossed outdoor space. However, just as easily, one can see how wind speeds are higher in High Holborn Street, to the south, and become even higher still further to the east, close to centre point. When wind blows from the west, there’s more turbulence in both courts, but still, barely noticeable in comparison to High Holborn or even New Oxford Street’s. This contrasting high wind speeds in the surrounding streets will create a greater perception effect on passers-by who will feel lower wind speeds in the courtyard.
South Wind Direction: More frequent in Autumn than in Spring.
When carrying on with the simulations, it becomes evident that northern wind directions start to become a problem for the pedestranized Museum street between New Oxford and High Holborn. Nevertheless, it is only a problem inside the courtyard when wind blows from the east. This wind is not downdraft wind. In conclusion, the simulations suggest that there is higher turbulence in the overall proposed area than in the existing court of Central St. Giles. Nevertheless, the proposed courtyard is twice the size of that of St. Giles, and there’s still an area as big as that, which is protected regardless of where the wind comes from, in the inner part of the proposed courtyard.
Figure 95: Wind Rose for 13:00 hrs throughout the year and wind simulations from all directions. Source: After Ecotect Analysis 2011 + WinAr, and Weather tool. 43
5 – DESIGN VERIFICATION
Outdoor Design Verification P.E.T was calculated for the proposed courtyard, for the time of the year that was deemed as having external conditions which allowed for the use of outdoor spaces. For all the parametric P.E.T. studies, the following personal data was used: Height : 1.75 m. Weight: 75 kg. Age : 30 Gender : male The activity is sitting down, and for that, a metabolic rate value of 80 W. has been adopted. It may be considered as high, but it was adopted as such because the activity should involve having lunch, which would increase the metabolic rate as digestion happens. The Clo value will be given for each season, as this changes from one to the other, but remains the same for the day. The global radiation and air velocity in each case will be given bellow each figure along with the final P.E.T. result, as these are the variances which show the degree of the adaptive comfort possibilities the users enjoy. These variances will represent someone moving from a shaded area to a sunny one, or a protected area to less protected one. For the solar radiation, values have been calculated using the Ecotec Analysis 2011 software (see appendix). For the wind, speeds of 0.5 m/s and of 1 m/s have been simulated.
Spring 13:00 hours. (figure 96) External Conditions: Dry bulb temperature: 14.8°C Relative Humidity: 48% Octas: 2/8 Clo: 1.2 On the Spring equinox the overall P.E.T. is quite low, but because of the influence of the sun’s direct solar radiation, people will tend to cuddle in the solar patch which offers more than a 5°k difference in comparison to shaded areas. Being the Spring equinox, the time when the sun is at it’s lowest angle in the whole spring, this is not a problem, because as of this point it will start to be higher and it will emit higher radiation values.
44
Shaded, protected areas: Wind Speed : 0.5 m/s Global Radiation : 57 W/m ² P.E.T. : 10.4°C
Shaded, less protected areas: Wind Speed : 1 m/s Global Radiation : 57 W/m ² P.E.T. : 9.7°C
Figure 96: P.E.T. Studies for a Spring Equinox at 13:00 hrs
Sunny, protected areas: Wind Speed : 0.5 m/s Global Radiation : 280 W/m ² P.E.T. : 16.2°C
Sunny, less protected areas: Wind Speed : 1 m/s Global Radiation : 280 W/m ² P.E.T. : 14.3°C
Spring 17:00 hours. (figure 97) External Conditions:
Shaded, protected areas: Wind Speed : 0.5 m/s Global Radiation : 23 W/m² P.E.T. : 8.7°C
Shaded, less protected areas: Wind Speed : 1 m/s Global Radiation : 23 W/m² P.E.T. : 8.1
Figure 97: P.E.T. Studies for a Spring Equinox at 17:00 hrs
Sunny, protected areas: Wind Speed : 0.5 m/s Global Radiation : 142 W/m² P.E.T. : 12°C
Sunny, less protected areas: Wind Speed : 1 m/s Global Radiation : 142 W/m² P.E.T. : 10.7°C
Dry bulb temperature: 13.6°C Relative Humidity: 48% Octas: 2/8 Clo: 1.2 Given that the day became even cooler, there’s going to be less people in the courtyard, and although the sun’s intensity decreased substantially, people are still going to try and sit in the sun patches, and if possible in the protected areas, which will be further in, as long as the wind doesn’t blow from the east. (see wind simulations). 45
5 – DESIGN VERIFICATION
Summer 13:00 hours. (figure 98) External Conditions: Dry bulb temperature: 24.1 Relative Humidity: 46% Octas: 1/8 In the summer there’s going to be plenty of people outdoors given a good day. Umbrellas could be used to offer more adaptive opportunities. The sun floods the courtyard at 13:00 hours. Reading the P.E.T., one can effectively how people in protected areas to the sun will be quite hot, but may be willing to tolerate such exposure while enjoying the sun. In any case, moving to the shade will achieve a P.E.T. drop of about 5°K, a significantly higher difference when comparing moving from an area of 0.5 m/s wind speed to one of 1 m/s. 46
Shaded, protected areas: Wind Speed : 0.5 m/s Global Radiation : 104 W/m² P.E.T. : 21.2°C
Shaded, less protected areas: Wind Speed : 1 m/s Global Radiation : 104 W/m² P.E.T. : 20.3°C
Figure 98: P.E.T. Studies for a typical summer day at 13:00 hrs
Sunny, protected areas: Wind Speed : 0.5 m/s Global Radiation : 322 W/m² P.E.T. : 26.6°C
Sunny, less protected areas: Wind Speed : 1 m/s Global Radiation : 322 W/m² P.E.T. : 24.6°C
Summer 17:00 hours. (figure 99) External Conditions: Shaded, protected areas: Wind Speed : 0.5 m/s Global Radiation : 62 W/m² P.E.T. : 15.4°C
Shaded, less protected areas: Wind Speed : 1 m/s Global Radiation : 62 W/m² P.E.T. : 14.6°C
Figure 99: P.E.T. Studies for a typical summer day at 17:00 hrs
Sunny, protected areas: Wind Speed : 0.5 m/s Global Radiation : 251 W/m² P.E.T. : 20.5°C
Sunny, less protected areas: Wind Speed : 1 m/s Global Radiation : 251 W/m² P.E.T. : 18.6°C
Dry bulb temperature: 18.9°C Relative Humidity: 58% Octas: 3/8 As the day draws to an end, and the air temperature is cooler, shaded and windy areas start to become less desirable, nevertheless, in the sun the P.E.T. is quite high. The sun still has an effect of about 5°k, while the wind’s effect is almost 2°k, and it is felt higher in the sun, than in the shade. 47
5 – DESIGN VERIFICATION
Figure 100: Office plan view in a overcast sky day and daylight factor analysis.
Indoor Design Verification - Offices Daylight Studies Following the findings from the predesign analysis of the shoe box, the offices are located in an area of the building which is obstructed most of the year, having one of the main facades oriented due north, towards New oxford Street and the other main facade facing Duns Passage. In order to take advantage of the double height, a mezzanine was created to house the common and more flexible areas such as the hot desks and the Cafe (figure 100). The garden which receives direct sun light from March to October has the potential of being a succesful transitional space, which could be used as a working area for meetings, etc. The garden can also be accessed from the corridor of the adjacent residential block and can be used by them during the weekends or after the working hours. This garden also ventilates the core for these dwellings. As seen in the figure 101, the tall windows provide good daylight distribution with a uniformity ratio (DFmax/DFmin) of around 4 on the workplane (700mm above the ground), which stays well below the suggested threshold of 10 ( Baker, N 2002). In addition, an average Daylight factor of 5% is found in most of the working areas (figure 101), which guarantee a minimum of 300 lux at 80% of the working hours. This way, artificial light is assumed to be used only for a few hours during the winter (early in the morning and evening), when it is unavoidable. 48
Figure 101: Office plan daylight factor distribution. Sky Conditions: 6000 Lux Source: Radiance
Thermal Simulations
Figure 102: Office plan view in typical winter day.
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Figure 103: TAS simulation for the office in a typical winter week (04/01 - 10/01). Free Running
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In the thermal simulations, a typical floor plan was modelled and it was set a single zone for the entire plan, considering that the internal layout will be organized in an open plan configuration (see appendix). The same constructions and internal conditions as the shoe box were used (see pre design studies chapter), apart from the U-value of the glass that was improved from 1,77 W/m2K to 1,28 W/ m2K (Double Glazing, Argon Filled). This change in the specification is based on the fact that this glass was already used in the St. Giles project (2010), and this building is being refurbished aiming a good performance for at least the next 50 years. Also it is important to highlight that the offices don’t rely on the solar gains to achieve comfortable free running conditions in the winter, so in this case the lower U-Value will only increase the thermal performance of the working environment. As Shown in the figure 103, the resultant temperature of the office plan is within the calculated EN 15251 comfort band for 90% acceptability during all the hours of the day, eliminating the necessity of using space heating. However a lower appliances scenario was also tested, considering that in the next few years the appliances will become more efficient and the use of laptops will be more frequent. The LED lights can also reduce the lighting gains by up to 35%. In this case the temperature was lower than in the current scenario. Nevertheless during the occupied hours it stayed within the comfort band. In order to do a more accurate verification concerning the comfort conditions especially in the first hour of the day, a thermostat was set to 18°C during the occupied hours (08:00 – 19:00). The heating load turned out to be almost negligible. In the case of the appliances becoming even more efficient than the considered scenario, a heat recovery system could be installed which would offset the residual heating load. 49
5 – DESIGN VERIFICATION
Figure 104: Office plan view for a typical summer sunny day.
Indoor Design Verification - Offices Ventilation Strategies In the summer, the garden plays an important role in the ventilation strategy. During daytime the area facing New Oxford Street, which is a heavy traffic road, can be ventilated just through the garden which faces the courtyard while having the north facing windows shut (figure 104), avoiding this way noise and pollution. In addition the windows facing duns passage which is a quieter and more protected area can be opened, allowing cross ventilation. During night time, the lower level windows facing the garden are shut for security purposes, however the cross ventilation can be achieved by opening the window of the mezzanine (figure 105).. Figure 105: Office plan view for a typical summer night. 50
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The figure 106 shows the resultant temperatures in the office area during a typical week of August which is the hottest month. The temperature in the offices stay within the calculated comfort band during the working hours, proving that the ventilation strategy is efficient. During the hottest hour of Saturday (11/8), it is possible understand clearly the effect of the thermal mass, when the resultant temperature indoor is lower than the outdoor temperature. Also it is important to highlight that in the simulations the offices were assumed to be unoccupied during the weekends.
Figure 106: TAS simulation for the office in a typical summer week (09/08 - 15/08). Free Running
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Considering that in the next years extreme temperatures are likely to be more frequent due to climate change, another simulation was run with the purpose of verifying the thermal performance of the offices in a probable future scenario (figure 107). In order to simulate this scenario, the hottest days registered in the climate data used, were chosen to represent what would be the future extreme temperature conditions. It was also assumed that a change in the occupancy patterns could generate higher internal heat gains. This meaning, the density of the working area could increase from 10 m ²/person to 8 m ²/person. The results show that it is possible to keep the temperatures in the same comfort zone by increasing the ventilation since London has a relatively mild climate even during the summer. This way the temperature indoor will follow the temperature outdoors. In the simulations, the ventilation was meant to be increased by opening all the windows that are located in the same level as the working desks during day time, apart from the windows facing New Oxford Street that were keept shut in order to maintain the acoustic comfort. In days when the temperature outdoor could rise above the comfort band, other adaptive measures could be applied by the occupants in order to restore the comfort. A good example is mentioned by Baker (2002), when the comfort temperature could be reduced by 3°C, if the business suit ( clo value1.0) was replaced by a pair of shorts and tee-shirt (clo value 0.3). This way, one can also assume that in future scenario companies will be more aware about these issues, being therefore more flexible in regards to dress codes and adaptive opportunities.
Figure 107: TAS simulation for the office in the hottest summer days (18/08-20/08).
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5 – DESIGN VERIFICATION
Indoor Design Verification - Residential Daylight Studies To carry out the design verification for the daylight performance of the residential units, two typologies were selected namely the 1 Bedroom apartment and the 3 Bedroom apartment. In both cases the simulations were done considering the obstructions and their respective orientations so as to get a reading for the least ideal scenario. These daylight studies were simulated to verify the findings from the shoebox study carried out during the pre design studies. The 1 Bedroom apartment comprises a window to floor ratio of 25%. Figure 108 illustrates the daylight simulations for the lower level of the 1 Bedroom apartment clearly indicating that on an average the entire floor achieves a good daylight penetration, with the minimum daylight factor of 2.0% in the kitchen, which is the minimum value as per the BS8206 Code of practice. The living room is sufficiently lit with a daylight factor of 5.0+% near the opening and 3.0% in the centre of the room as opposed to the minimum of 1.5% recommended. Figure 109 shows the upper level where 1.5% daylight factor was achieved, which is higher than the minimum of 1.0% prescribed for bedrooms by the standard. Thus the simulations show the apartment is more than sufficiently lit except for the kitchen which achieves the lowest daylight factor prescribed by the standards.
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Figure 108: Daylight factor simulation for the lower floor of the 1 Bedroom apartment.
Figure 109: Daylight factor simulation for the upper floor of the 1 Bedroom apartment.
Figure 110: Daylight factor simulation for the lower floor of the 3 Bedroom apartment.
The 3 Bedroom apartment comprises a window to floor ratio of 28% facing the South West orientation. Figure 110 illustrates the daylight simulations for the lower level of the 3 Bedroom apartment. The living room achieves a daylight factor ranging from 5.0+% to 3.0%, similar to the case in the 1 Bedroom apartment. The kitchen has a daylight factor of 2.5% and most of the bedroom achieves 2.0%, higher than the minimum specified by the BS8206. Figure 111 shows the daylight factor values for the upper floor which comprises of two bedrooms. Both the bedrooms have daylight factors ranging from 4.0% to 1.5% while the staircase obtains a 2.5% daylight factor. In this case it is clearly observed that the 3 bedroom apartments are sufficiently day lit.
Figure 111: Daylight factor simulation for the upperf loor of the 3 Bedroom apartment. 53
CH 5 – DESIGN VERIFICATION
Indoor Design Verification - Residential
Figure 112: Apartments view for a typical winter sunny day.
Thermal Studies As shown previously in the daylight analyses, the one bedroom and three bedroom apartments are the typologies chosen to be simulated thermally in order to predict the performance of the units with different occupancy conditions and orientations. The one bedroom flat faces northwest and the three bedroom one faces southeast. Both typologies have a window to floor ratio below 30%. The same internal gains and construction materials as the shoe box were used in the simulations (see predesign studies chapter), apart from the glass of the northwest facing apartment which has its U-value improved from 1,77 W/m2K to 1,28 W/m2K (Double Glazing, Argon Filled) in order to offset the low heating loads found in the pre design simulations. An additional change from the shoe box was the addition of a heat recovery system, with the purpose of reducing the heat loss. In this case the fresh air required will be provided in the same temperature as the internal air. Based on the research done for Central St. Giles the team defined different occupancy patterns for each kind of typology. This way, the one bedroom apartment is meant to be occupied by a young professional, which usually stays at home only between 19:00 - 09:00. On the other hand, the three bedroom apartment is assumed to be occupied by a 4 people family with 2 children, where the high occupancy hours are between 19:00 – 08:00 (4 people), and after 15:00 when the kids come back from school (3 people), Figure 113: Apartments view for a typical winter night. 54
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Figure 114: TAS simulation for the one bedroom apartment in a typical winter week (04/01 - 10/01). Free Running
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Different window components were employed to allow adaptive opportunities so that the occupants can interact with the building in order to achieve visual and thermal comfort without using artificial heating and cooling. The figures 112 and 113 show that in the northwest facing apartments, internal shutters where used with the purpose of reducing the heat loss during night time through the glazing elements and also to create a darker environment in the bedroom by blocking the outdoor lights. On the other hand, in the southeast facing apartment the night shutters are external and during day time when they are opened, they also exert the function of an overhang, which is an effective shading device that blocks the direct solar radiation in the summer when the sun is in a higher angle and allows the direct solar radiation in the winter when the sun is lower in the sky. The figure114 shows a TAS simulation for the one bedroom flat in a typical January week. An average of 20°C was found, which is in the middle of the comfort band calculated for 90% acceptability using the EN 15251 equation. However a low appliance scenario was also tested with intention of checking the robustness of the design in possible future conditions. In this case the internal gains considered for the kitchen and living room were 2.1 W/ m² (lowest scenario specified by the PHI) and 1.6 W/m² (25% lower than the current scenario). The temperatures found were slightly lower; however they are still above 18°C confirming that the apartment could still operate in free running mode. A bedroom of the southeast facing apartment was also tested with the same internal conditions. As shown in the figure 115, the average temperatures are not as high as the ones found in the northeast facing flat simulations, since the prevailing sky conditions along this week are cloudy or overcast, meaning that during these days the apartments receive more diffused radiation rather than direct.
Figure 115: TAS simulation for a bedroom of the three bedroom apartment in a typical winter week (04/01 - 10/01). Free Running 55
5 – DESIGN VERIFICATION
Figure 116: Apartments view for a typical summer sunny day.
Indoor Design Verification - Residential Ventilation Strategies During the summer different strategies of ventilation were adopted with the intention of increasing the occupant’s range of opportunities to deal with noise pollution, and thermal comfort. The most challenging situation was concerning the apartments facing High Holborn Street which is a road characterized by its heavy traffic. In this case, it was assumed that the bedroom would have low occupancy during day time, being ventilated during those hours (figure 116), allowing this way the windows to be shut during night time (figure 117). On the other hand the kitchen and the living room area which are considered to be occupied for at least one person during day time, could take advantage of the thermal mass (concrete slab) and be ventilated only during night time (22:00 – 08:00). Figure 117: Apartments view for a typical summer night. 56
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Figure 118: TAS simulation for a bedroom of the three bedroom apartment in a typical summer week (09/08 - 15/08). Free Running
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The figure 118 shows that the average temperature of the bedroom during a typical august week is around 25°C, which is 3°C lower than the upper level of the comfort band. This data confirms that the daytime ventilation strategies and the solar control (overhangs) are being efficient. In the living room and kitchen area, shown in figure 119, even with higher internal gains and higher occupancy, the night time cooling strategy is providing comfortable temperatures during the occupancy hours. In addition the thermal inertial reduces the peak temperature of the hottest day (11/8). A future scenario with higher external temperatures was also simulated (see appendix), and it was found that in those conditions, the living room area must also be ventilated during most of the daytime, in order to achieve comfortable temperatures. In this case the physiological cooling effect provided by the air movement is not being considered, however it is known that it could reduce considerably the occupant’s physiological temperature by increasing the rate of sweat evaporation from the skin. According to Givoni(1994), such comfort ventilation is desirable even when the temperature outdoor is higher than the indoor, this way the threshold of comfort can be shifted upwards. In addition, the broad range of adaptive opportunities that can be applied in residential units (e.g clothing adaptation, moving from one room to the other, etc.) have an important role in increasing the occupants satisfaction with the environment.
Figure 119: TAS simulation for the kitchen of the three bedroom apartment in a typical summer week (09/08 - 15/08). Free Running 57
5 – DESIGN VERIFICATION
Materials The materials chosen for the building have relatively low embodied energy values and maintain the character of the building with the surrounding neighbourhood and streetscape. Figure 120 illustrates the materials used for the design proposal with their respective embodied energy values. Since the development is partly refurbished, a portion of the existing building shall be demolished, leaving behind a certain volume of concrete waste as shown in Figure 121. The approximate volume of concrete demolished is 6500m3 and the volume retained is 7100m3 giving a 52% volume of concrete being retained. Hence the team decided to recycle as much as possible from the demolished portion of the existing building. The waste concrete is crushed and then will be reused as an aggregate along with a virgin aggregate for the new concrete in the construction. The crushed concrete shall also be used for the landscaping elements and the pavements within the development. Approximately 30% of the waste concrete gets recycled while the remaining has to be taken away. To prevent the transportation of the remaining waste concrete, the debris shall be filled in that part of the existing basement which shall not be part of the new development with a volume measuring 6000m3, illustrated in Figure 122. Brick is used in a smaller part of the facade as it has a higher embodied energy than concrete. This is due to its higher embodied energy value and to maintain the architectural character and texture of the building. The external concrete block wall will be finished with paint containing natural resin emulsions. These paints appear as conventional petrochemical emulsions but are free from any solvent and are biodegradable (Smith, P. 2005). The shutters on the facade are to be made of timber since it has a lower embodied energy of 10 MJ/kg as opposed to aluminium (155 MJ/kg) and steel (20 MJ/kg) shutters (Hammond, G. 2011). The particular type of timber selected is Sweet Chestnut and belongs to the hardwood species of timber that are locally grown in the UK. They have a medium texture, good durability and are extremely resistant (Wooley, T. and S. Kimmins 2000).
Figure 120: Facade materials.
Volume of existing concrete Volume of demolished concrete
Area of Basement not to be used Area of Building
Figure 121: Graph comparing the amount of concrete demolished. Figure 122: Plan showing unused basement area left from existing building. 58
Renewable energy sources The need for offsetting any residual load in the proposal was one of the key objectives for the team. The residual loads can be broadly classified as energy required for the electrical appliances and lighting needs followed by the need of hot water for domestic purposes. This was achieved by the use of Photovoltaic/ Thermal Panels, a combined assembly of a PV module, for the conversion of electrical energy and a high efficiency flat plate solar collector for the conversion of thermal energy. Figure 124 illustrates a PV/Thermal (PV-T) array which consists of a photovoltaic module to convert light into electricity and a copper heat exchanger on the back to capture the remaining solar energy. The electrical load was calculated based on a situation for a typical apartment with the respective appliances and lighting equipment available in the present scenario as shown in Table 1. The roof of the building would receive a global radiation of 1150 kWh/ m2/y obtained from the Satel-Light website (www.satel-light.com) at an angle of 30째 from the horizontal. Since the roof receives almost no obstruction of sunlight the roof was the ideal location to affix the PV-T panels. The northern portion of the roof was demarcated for placing the panels covering almost 75% of the roof with an area of 1500m2(figure 123). The annual energy production was then calculated with a panel efficiency of 17% using the equation (Max Fordham & Partners 1999) as follows: Annual Energy Production = Global radiation x panel efficiency x 0.95 x correction factor at 80% x accounting loss factor at 90%
PV-T Panels on the roof of the building Roof of the building
With this area, panel efficiency and global radiation the annual energy production was calculated to give 200,700 kWh/year while the electrical energy production calculated, as seen in Table x, is 190,000 kWh/year. Hence the electrical load for the residences are met with the PV-T panels with the present scenario while the hot water demand is provided by the thermal energy generated from the panels. The residual loads for the offices could not be met with the current scenario however in the future scenario,up until 2050, enough progress would be made to achieve panels with a higher efficiency and more energy efficient appliances which would then offset the residual loads for the offices and residences.
Figure 123: Roof plan with the position of the PV-T panels
Figure 124: Arrangement of a PV-T Panel (Source: Smith, P. 2005)
Table 1: Estimated electric loads for a typical residential unit.
1 Calculated by the addition of the yearly electric consumption of all the appliances in a typical appartment multiplied by the number of apartments in the development. 2 Calculated by the addition of the yearly electric consumption of all the lighting equipment in a typical appartment multiplied by the number of apartments in the development.
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6 – CONCLUSIONS
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Figure 125: Conclusion Diagram 61
6 – CONCLUSIONS
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The experience of realizing this project left the team with quite a few findings. A “room in the city” can be achieved throughout most of the year by just protecting from the wind and guaranteeing solar access. Efforts for providing solar access in the winter times are simply not justified, because although it is a considerable amenity, it will not be enough to encourage the use of outdoor areas. This encouragement proves to be important since it has a social agenda provoking more social interaction through chance encounters, and an environmental agenda, since people outdoors do not require the use of electricity as a general rule. A free running building can be achieved in London with an appropriate shape which should not be deep planned. This is true as long as the use of low U-value materials is implemented. The energy requirements for running the appliances in the residential areas are offset by the photo voltaic thermal solar (pv-t) panels provided, nevertheless, these are not enough to offset the office consumption. This could indicate that more renewable energy sources should be explored. However, the efficiency of the pv-t’s is becoming increasingly higher. The language of sustainable architecture is one that proves to be symbiotic with it’s surrounding. It is not deterministic, there’s no linear path to a design, but different strategies should be weighed against each other and their different combinations in order to add more quality through different aspects of comfort. The envelope plays a major role environmentally which should provide guidelines for the aesthetics. Adaptive opportunities should be made available and very clear for the occupiers in order to properly compete with conventional strategies such as turning on a switch. One final finding was that even in London’s climate, orientation is not of a significant importance when dealing with materials with relatively low U-values, and keeping the window to floor ratio below 30%. Actually the increase in window size proved to be more of a problem for overheating than for heat loss, due to the high heat gains in unprotected openings.
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References Baker,N. And K. Steemers (2002). Daylight Design of Buildings. James & James Science Publishers. Baker, N.V. (2009). A Handbook of Sustainable Refurbishment: Non – Domestic Buildings. Earthscan, London. Building Regulations(2006). Part F. Ventilation. Published by NBS for the Office of the Deputy Prime Minister. Camden Planning Brief (2004). CIBSE (2006). Guide A. Chartered Institution of Buildings Services Engineers, London. CIBSE (1999). Lighting Guide LG10. Daylighting and Window Design. Chartered Institution of Buildings Services Engineers, London. Augspach, Ben Dayan, Deotarase, Pinto de Oliveira Cotta, (2011) Central St. Giles Report. Fordham, M. Et al (1999) Photovoltaics in Buildings: A Design Guide. DTI. Givoni,B. (1994). Passive and Low Energy cooling of Buildings. Van Nostrand Reinhold. Hammond, G. and C. Jones (2011) Inventory of Carbon & Energy (ICE)’ V2.0.Sustainable Energy Research Team (SERT) of the University of Bath Hegger et al.(2007). Energy Manual. Sustainable Architecture. Edition Detail. Roaf, S. (2003) Ecohouse 2: A Design Guide. Architectural Press. Smith, P. (2006) Architecture in a climate of change: A guide to sustainable design. Architectural Press. Szokolay, S. (2003 / 2008). Introduction to Architectural Science.The basis of sustainable design. Architectural Press. Wooley, T. and S. Kimmins (2000) Green Building Handbook: Volume 1: A Guide to Building Products and their Impact on the Environment. Spon. Yannas,S. (1994). Solar Energy and Housing Design. Volume 1: Principles, Objectives, Guidelines. AA publications
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