Be0898 201415 johnston

Ellison Building, City Campus

Building Design & Performance Critique BE0898 W10030207

Proposals for refurbishment – Ellison Building, Northumbria University.

I have decided to pursue the refurbishment option for the Ellison building as I believe this would potentially allow the university to achieve the goals of improving environmental performance and user satisfaction with the minimum of disruption and reduced risk of having to find temporary teaching spaces for lectures/seminars.

In its current form, many areas of the Ellison building have a number of flaws which may inhibit it from achieving its potential in both usability and environmental performance. Many of these are symptomatic of buildings constructed in the same period throughout the 60’s & 70’s. While the concrete structures high thermal mass which can offer many benefits, the poor quality of insulation and the poor air tightness associated with these older buildings results in a relatively average energy performance rating of grade D. The proposals contained will suggest ways in which these qualities can be improved on a much shorter works program than an alternative new build program. The bulk of this work could be carried out over the summer break period minimizing the disruptions to students & staff.

The blocks of the building seem to be built to a variety of different specifications and refurbished at different periods over its lifespan. While some blocks have composite cladding systems & modern windows, others have much of their original concrete/stone cladding & single glazing. Ventilation is often carried out through the placement of vents in the window areas so the air tightness performance of much of the building, block A in particular, is likely to be very poor. The building also makes heavy use of heating & air conditioning units. This is again symptomatic of poor thermal performance. During daylight hours the solar gain on the heavily glazed areas equipped with single glazing would heat the rooms to the point they would require air conditioning to cool them. These same areas would likely require heating when the solar gain was more limited. Reducing these fluctuations in energy gain & loss to the ambient surroundings is critical to ensuring the space is as efficient & user friendly as possible.

External envelope.

Of the blocks, only Block D has a modern composite cladding system in place with double glazed windows. These represent a much high performing fabric than the systems in place elsewhere in the building. There are a number of systems which could be employed to upgrade the other blocks to look more in line with Block D & help the building meet Part L of the building regulations. This would also have the added benefit of making the entirety of the Ellison building look more integrated than in its current fragmented form.

The placement of modern glazed curtain walling systems incorporated into the cladding system could also improve the lighting quality of the building while reducing the need for electrically operated lights during daylight hours. Some of these systems such as those which incorporate “lowe coatings” (Dow Corning, no date) can achieve a high thermal performance and reduce the heating loads on buildings when compared to traditional glazed systems. This is of particular importance on those parts of the building exposed to sunlight, as not only the thermal loss through these windows would be considered, but the gain which could lead to increased use of mechanical cooling would

need to be taken into calculations. These methods would represent a significant alteration to the building as in most cases the faรงade would be almost entirely removed leaving only the structural elements behind. As an alternative, a much less invasive method would be to fix composite cladding panels to the external leaf of the building. This would increase the thickness of the walls and would likely require the replacement of the window systems, but as these are likely to be replaced anyway with any major refurbishment works, this should not be an issue.

On the south east faรงades, PV panels as sun shades could also be employed. The use of some of these rooms is often inhibited by light entering the glazed areas causing the blinds to require drawing and artificial lights being turned on inside. A brise soleil incorporating PV panels could offer the dual purpose of energy generation along with making the spaces usually subject to higher intensity sunlight to remain at a much more usable and comfortable level, much like the campus east building. These could also be mechanically operated if required to further maximise the energy generation, or the focus could be on the light intensity measured behind the system.

The roof areas are also underutilised with much of the traditional flat roof taken up with only external air conditioning ductwork. Many of these areas could be utilised for rainwater harvesting systems or PV panels without impacting causing unsightly visual qualities for the building users or public. Any methods to take advantage of rainwater capture for none potable uses would require associated works for pipework and storage somewhere on site. These could potentially be placed in the soft landscaped areas beneath the public open spaces enclosed by the building. Although these may be impractical to meet the water needs for the entire building, it would go some way to reducing the operating costs for the building in the future along with increasing its environmental performance. It also has the added benefit of adding and additional quantity of storm water retention, reducing the amount of water as run off which potentially contributes to localised flooding.

Another option for the roof areas would be to employ a green roof system. These can offer high performance for thermal insulation while having the added benefit of promoting bio-diversity. A commonly used example of this involves the Rolls Royce Factory (alumasc, 2014). This factory employed a large sedum roof which incorporated a rainwater harvesting system. The roof was so successful at promoting the biodiversity of the area it is home to a large number of rare UK ground nesting birds during breeding months. They are also very low maintenance as the sedums do not grow taller than a few inches in height. During extended dry periods, these systems may require some general maintenance in the form of watering to ensure the mats do not dry out and become damaged.

Insulation to external walls may also be improved by the fixing of insulation boards to the internal walls. While this is less effective than modern insulation as part of a cavity wall system, it will help improve heat retention to the building. A downside to this would be a slight reduction to room size by the thickness of the new insulation panel/plasterboard thickness, but in some of the rooms there should be space to accommodate this as these spaces are already compromised by the PCC columns which form the buildings structure (see below)

Column directly in front of seat in lecture theatre.

The improvements to the windows would also help in relation to air tightness. At present the current windows are prone to draughts as they do not form a particularly good seal. The single glazed units also do not perform particularly well with sound insulation, which can affect the overall usability of the room. Given the nature of the building, acoustic insulation would be highly beneficial to allow lectures, seminars & exams to be carried out without distraction to the occupants by the surrounding traffic.

Large single glazed units Heating & Electrical Much of the heating and power supplied to the Ellison building originates from traditional methods.

There are currently some more modern & energy efficient installed but these do not contribute to the energy requirements for the building and are primarily for demonstration purposes e.g. the CHP unit in laboratory areas. The building currently has a number of plant areas dedicated to power generation, air conditioning & extraction for the laboratory areas. While these extraction units would likely have to remain, the power & air conditioning requirements may be able to fit within the current plant areas. Space could also be made available by reducing the air conditioning requirements to the building. A passive ventilation system could be employed to some of the areas serviced by the large open stairwells to the circulation areas. These areas could also be controlled by a building computer control system which would actuate the windows depending on the internal climate conditions for that area. Monitoring the buildings statistics & usage also has the added benefit of engaging with the building users and encouraging them to be aware of their impact on building energy use. Systems such as these were employed on a project at Aykley Heads, Durham called The Rivergreen Centre. (Rivergreen, 2015) The combination of these in conjunction with a biomass boiler system heavily reduced the reliance on power & heat generation from fossil fuels.

Combined heat and power systems offer much higher efficiency rates when compared to separate traditional power and electrical systems. These systems make use of latent heat generated with power which is usually lost to the surrounding areas. Evaluations of these systems have shown a much higher efficiency rating than separate systems servicing the same space.

Typical CHP Efficiency Comparison (Energy International, 2014) If a large enough unit could be fitted, a much higher proportion of the buildings heat & power usage could be generated in this way. The higher efficiency would allow for the reduction of energy bills, but also contribute to a much more modern and efficient image for the university. Other methods which are currently employed on site on a small scale could also potentially be expanded to contribute to the overall building power & heating requirements.

The low carbon generation of this method can be further enhanced when selecting the fuel type to be used. CHP units can make use of biomass further reducing the reliance on traditional fossil fuel generated energy. These fuel sources are usually sourced from responsibly managed woodland which is grown specifically for the purpose of fuel, or from waste products.

As previously mentioned much of the roof space is currently underutilised. Subject to approval by planning, other forms of low or zero carbon energy generation methods could be employed via the installation of wind turbines & air source heat pumps.

Turbines are often labelled as unsightly and may not be accepted by planners for an inner city building such as Ellison, but air source heat pumps may be hidden behind louvres in a plant room.

This would hide the condensers and potentially making them a much more attractive option. A problem to consider would be condensation. Given the heat differential in air and the latent humidity, condensation and icing on the units can become a problem potentially preventing them from working. Dehumidifiers may be employed to try and counter this, but again this requires the space reducing the area available for energy generation.

For wind power, the building would likely require a large number of smaller turbines, or a small number of rather large turbines to contribute a significant proportion of the electrical requirement.

Also given the city location, there are many buildings surrounding which could act as a wind break, potentially disrupting the airflow and therefore the energy generation potential for this sytem. For these reasons this option may not be particularly practical.

Ground source heat pumps may also provide renewable energy source but a low visual impact.

Much like the rainwater attenuation systems, these can make use of the already present outdoor

areas and often only require a few feet of excavation. These work by making use of a closed system which contains a condenser & an evaporator. Refrigerant is then piped around the system and the temperature difference allows for a heat transfer to take place. This allows for the heat to be taken out of the ambient environment and used elsewhere. Likewise the system can be reversed to remove heat and return it to the surrounding ground. While these systems do not require deep excavations, they can benefit from them. The borehole method allows for deeper excavations to be used. Ground source heat pumps work most efficiently when the ambient temperatures are relatively warm in the winter and relatively cold in the summer. Temperatures in excavations often remain much more constant and at around 10m, only differ by a few degrees across the year. This allows the refrigerant in the system to have a cooler area to lose heat in the summer and a warmer area to take heat from in the winter. These may come with their own problems considering the nature of an inner city environment. Underground sewers, service tunnels and underground rail cross the city beneath the surface. During the construction of city campus east, a large sewer was struck by an auger resulting in significant damages and delays. Given the depth of the bore holes required for the ground source pumps, ground investigation would need to be quite detailed to ensure these are safe to carry out.

Internally, electrical fittings could also be improved to enhance the overall usability of the building.

The use of LED lights represents a higher initial capital cost, but lower operating costs due to reduced electrical consumption. This allows for a reduction of the whole life cost of the building along with reducing the requirement for energy generation.

Finishes Egg crate ceiling tiles in suspended ceilings will allow the benefits of an exposed concrete ceiling for thermal absorption & retention to be realised without exposing the likely poor quality concrete finish which would be present given the age of the building (1999, Gold CA & Martin AJ p51). It would also allow for the retention of the current recessed lighting systems in areas where these were already installed, meaning only the bulbs may require replacement. This as discussed above could be replaced with LED bulbs reducing the electrical loading on the building supply.

One major disadvantage identified which is much harder to remedy in a refurbishment option is the circulation of occupants around the building. At present the buildings contain one main corridor through the central area which at busy times can become very congested. Given the concrete structure is fixed in these proposals it would be increasingly difficult to improve this without encroaching on the teaching spaces which would not be desired. This is a symptom of the building being designed at a time when the number of students was likely much lower, or less emphasis was placed upon efficient occupant traffic. This was a consideration in favour of demolition and rebuild over refurbishment, but ultimately I felt the demolition option would result in a much more expensive project, with extensive disruption to teaching & research programs.

A combination of the suggestions above would improve the overall energy performance of the building, along with a more comfortable environment for the occupants. The improved energy

performance coupled with a large increase in energy generation from renewable sources should also allow for a vastly cheaper operating cost & improved whole life costs. These would likely come with a significant capital outlay at the beginning of the project, but would also help improve the image of the university by resulting in a much more modern building for students.

An added benefit of combining the technologies would be reduced electrical and heating supply loads which would allow any proposed energy generation sources to be of a much more practical size compared to those required to satisfy the current energy consumption. One important aspect to consider would be the overall design of the building and how these systems communicated and complimented each other. Ensuring the building is as efficient as possible from the outset and the systems employed to generate energy are suitable is paramount. If these are calculated incorrectly the building may have to revert to much more energy intensive ‘backup’ methods of power & heat generation to ensure the demand can be met at peak times.

The design must also be carefully considered to avoid the building components from negatively affecting the surrounding area. A prime example of this was found after construction of the ‘Walkie Talkie’, or 20 Fenchurch St in London, where the reflective glazing system coupled with the convex nature of the external skin caused a point on the street to be the focus off the suns energy on hot days. This resulted in damage to people’s vehicles and property in this area. (The Daily Mail, 2013)

References Gold CA, Martin AJ (1999) Refurbishment of Concrete Buildings - Structural and Service Options..

Bracknell, Berkshire: Oakdale Publishing.

Rivergreen Developments. (2014) The Rivergreen Centre, Available at: http://rivergreendevelopments.co.uk/placestowork.htm (accessed Feb 2015) Energy International (2014) No Picture Name, Available at: URL http://www.energyinternational.co.uk/CHPCalculator.htm Downloaded: Feb 2015 Dow Corning. (No date) Thermal Modelling Comparison of Typical Curtain Wall Systems, Available at: http://www.dowcorning.com/content/publishedlit/qb_a_thermal_modelling_comparison_of_typica l_curtain_wall_systems_1.pdf (Accessed: Feb 2015) http://www.theconstructionindex.co.uk/news/view/gecco2-secures-micro-certification-schememcs-installation - GSHP picture Alumasc Roofing Ltd (2014) Rolls Royce Factory, Available at: http://www.alumascroofing.co.uk/projects/commercial/rolls-royce-factory/ (Accessed: Feb 2015).

The Daily Mail (2013) Now the Walkie Talkie is Melting Bicycles, Available at: http://www.dailymail.co.uk/news/article-2409710/Walkie-Talkie-building-melting-bicycles-Lightreflected-construction-City-skyscraper-scorches-seat.html (Accessed: Feb 2015)

Reading List Gold CA, Martin AJ (1999) Refurbishment of Concrete Buildings - Structural and Service Options..

Bracknell, Berkshire: Oakdale Publishing.