Ventilation and Lighting Studies

I want to incorporate the modern light pipe design into a traditional wind catcher aesthetic. The brick of the wind catchers ties in with the brick aesthetic of the surrounding buildings of Cambridge. Modern architecture in Cambridge uses a very small material palette - brick and masonry, but in contemporary ways. I hope to achieve this with the aesthetic of the wind towers. The towers fit neatly into the 1400mm grid of the site, and are proportioned as three 1400mm cubes stacked on top of each other; where the top cube contains the air vents.

In the centre of the tower will be a reflective tube so light will bounce back and forth before it illuminates the spaces below:

The stack effect will help draw fresh air in and expel warm air, due to the temperature differences between the  air outside and the air in the subterranean depository. The blue arrows show fresh air, red arrows the stale air from underground; and the yellow arrows show light bouncing down the light pipe:

Geology & Site Constraints

For this section of group work, we researched bore hole data from the east of the site, just behind the library, to learn about the geology of the site:

0-1.2m below the turf is just topsoil, man made, this layer soaks up drainage from the site. Beneath the layer of topsoil is 3m of sand and gravel, composed mainly of fine particles of flintstone, chalk and limestone. A 2m layer of clay lies below this, which is fairly soft so pile foundations would be required to pierce into the calcareous mudstone (the supporting ground). The borehole data stopped at -20m, but I presume the mudstone layer continued below this.

The most interesting we discovered was the large amount of fossils that have been found in Cambridge, in the layer of mudstone. These are all marine fossils, indicating that Cambridge and The Fens region of Eastern England was at one time in history (we think the cretaceous era) submerged under water.

 

 

We researched the feasibility of construction on site, which with such a large site was quite straightforward. Construction vehicles have good links to the site from Grange Road,  less than 2 miles from the motorway.

 

 The diagram below is to scale, and shows:

Red rectangle indicates size of maximum (single) portacabin.

Blue rectangle indicates maximum size of lorry on UK road.

Orange circle shows maximum turning circle for the lorry (vehicle must be able to drive inside the orange doughnut shape). 

Green shape is the access/servicing road to the University Library, and must not be obstructed in construction.

Wind and Water Analysis

The prevailing wind on the site comes in mainly from the south-west. The wind is channeled around Robinson College west of the site creating high wind speeds on Grange Road, between my site and the college. The south west is the windiest part of my site and the north west is the least windy.

 Turbulence and Pressure

Arrows show prevailing winds from the south west. Turbulence is located in areas where high and low pressure meet, in this case in areas of difference in height or temperature (i.e. next to buildings)

Wind is sucked down into the site after kings College School and the surrounding trees, and up again over the Solar Trees and the Real Tennis Club.

Since warm air is less dense and creates less air pressure, it will rise, whilst cold air is denser and creates greater air pressure, so it will sink. When warm air rises, cooler air will often move in to replace it, so wind often moves from areas where it's colder to areas where it's warmer. The greater the difference between the high and low pressure or the shorter the distance between the high and low pressure areas, the faster the wind will blow. This is shown by rotating arrows in my diagram above.

Water Analysis.

The image below shows the nearest body of water, a small stream 40m north of the site. The stream is shallow and even in a record 100-year flood (shown in light blue) its flooding does not affect my site. Cambridge's irrigation initiative has drastically reduced the flooding levels of the River Cam and all of its tributaries (like the one below). The direction of the stream (flowing east towards the main River Cam) is shown in my model.

 

 Tributary

River Cam Context

Lighting, Ventilation & Volumetric Experiments

Keeping the environmental conditions underground suitable is extremely important for the map depositary. I wanted to provide natural ventilation, by using traditional wind towers, similar to ones seen in Accordia housing, by FCB Architects.

I also wanted to create a consistent aesthetic by designing the two buildings either side of the wind catchers and light pipes. I built a simple volumetric model illustrating this. I located the exhibition space on the crossroads, to promote the gallery as best I could on site. The positioning also keeps the height of the building away from the solar panels to the north:

The large blocks are the two buildings - the public and private buildings. The intermediate sized blocks are light-wells above the underground reading rooms; and the smaller blocks are the wind catchers. 

I treated the site plan as a canvas, placing the sculptural towers in a way that created public spaces in between.

I then thought to rearrange the elements on their side to provide seating. These seats could incorporate light-wells to naturally light the corners of the labyrinth below:

The composition of elements makes more sense when overlaid onto one of my earlier labyrinth. The wind catchers and light-wells are strategically placed over certain places within the labyrinth. These models are purely volumetric, diagrammatic, but will help form an idea of organisation structure on the site:

Map Depositary Ideas

To start off designing the 'labyrinth' I split the site into a grid of 1400x1400mm - a size large enough for an A0 filing cabinet and room for structure around it. 

I wanted the labyrinth to feel random, not at all organised. To create a random layout, I started off simple... flipping two coins. Whichever side heads was on dictated whether the path went left or right. If the two coins ended up both heads, or neither heads, the path continued straight on. The path was 2800mm wide, i.e. wide enough for two map cabinets to be wheeled past each other.

This process was lengthy but created very random layouts. After browsing for a map, members of the public would meet a librarian at the lift and follow them into the labyrinth to collect their map. The void areas in the map would be reading rooms, where people could study the cartography.

To inspire the aesthetic, I watch the film 'Labyrinth' (1986). One thing I noticed was the use of brick throughout the entire labyrinth. This consistent use of the same material helps the monotonous feel, and the maze-like effect, helping the characters become lost inside. Another thing I noticed was the use of artificial lighting in the underground tunnels, providing (in this case) specific lighting for the film.

I did numerous lighting experiments, and settled on two final lighting strategies.

1) Lighting in sections, fitting in with the grid structure.

2) Lighting in the end of each corridor, above each corner.

I think both are successful, and could be used together. For instance, natural lighting via a light pipe above each corner in the labyrinth, and motion sensitive lighting meaning that once you head towards the end of the corridor, lights above guide you through. The monotonous approach means that at a subterranean crossroads each direction would look equally spooky.  

I also considered a completely brick structure, similar to underground wine cellars; but decided the steel structure helped dictate the grid layout. Wine cellars are a common form of underground storage and provided some interesting lighting studies, as did converted nuclear shelters and tunnels. Lighting in subterranean environments is extremely important, and there are a number of places to provide lighting:

 

Design - Initial Ideas

I wanted to design from the inside out. The librarian at Cambridge University Library informed me that the ideal map storage conditions would be in flat, horizontal trays. The environmental conditions would, ideally be between 16 and 19 degrees Celsius. 

I thought the best way of achieving suitable environmental conditions would be to build underground. A bore hole/ geology study showed that after a layer of topsoil, the ground is mainly clay underneath the site.

In section, I plan to have two buildings, either side of the solar panels. The brief stated two building functions - a public building for a map gallery/exhibition and browsing; and private areas for staff, cartographers and deliveries. I read this as two buildings, one either side of the solar panels on the north of the site. 

In plan, the two buildings would have stairs/lift access down to the subterranean levels, where the map storage would be organised in a maze-like grid. I like the idea of needing a map to find your way around a map depositary. 

In section along the corridor, the map storage could be built into the structure. The lighting could come from above and the map cabinets could be placed into purposely-sized vaults:

Isometric view of the parti diagram. My basic concept is two buildings connected by an underground network of map storage. 

Technology: Solar Studies

I used my sketchup model to create solar studies showing the site in different times of year: 

Typical Spring/Summer morning. The site is under minimal shade from the University Library on the east:

Typical Spring/Summer midday. The site is under no shade:

Typical Spring/Summer afternoon. The site is under from the slightest shade from the west:

Typical Autumn/Winter midday. The site is under minimal shading from the row of trees to the south:

Typical Autumn/Winter afternoon. The site is under shading from trees to the south and Robinson College from the east:

Typical Autumn/Winter morning. The five-storey library cast long shadows over the east of the site:

The diagram below shows the area of most solar gain in summer, highlighted in orange. The solar panels are located in the area of most solar gain to optimise electricity production for the library. The grey shows the areas of least solar gain:

The diagrams below, collected from the Met Office, show that the south-east and Cambridge gets more sunlight than the rest of the UK. The maximum temperature recorded in Cambridge was 36.5 degrees Celsius, so all of this heat would be felt on site.