Cian Molloy reports that an energy retrofit cladding system developed by Cork Institute of Technology, Kingspan and AMS may give a new lease of life to dozens of institutional buildings built in the 1970s.
All public buildings must be near-zero energy buildings (nZEB) by 2018, according to the 2010 European Performance of Buildings Directive (EPBD). However, this is indeed a tough task, because many of Ireland’s public buildings predate the building regulations, have insufficient insulation and consume high amounts of energy.
Ireland’s Buildings are Worst CO2 Emitters
In terms of CO2 emissions, Ireland’s buildings score the worst in Europe, producing over 120 kg of CO2 per m2 of useful floor area – that is more than a 100 times worse than the best performer, Norway, and 10% worse than the second worst performer, the Czech Republic.
It is not surprising that industry analysts are predicting that, retrofitting Irish buildings to cut down their energy consumption is going to be the most important growth area in the near future. The only benefit is that the energy retrofit will offer valuable business to the construction industry that has now experienced five years of successive decline in activity.
So how will energy retrofit systems work and what kind of benefits can it bring? Cork Institute of Technology (CIT) is presently working on a Zero2020Energy project as a learning exercise for industry, colleges and students. This project demonstrates that the performance of existing facades can be easily and considerably enhanced.
The Department of Education and Science and research partners, AMS and Kingspan have funded an innovative, high-performance integrated window system that has been specifically designed for the existing facade at CIT’s buildings in Bishopstown. In addition to this, a new therm-strip curtain wall system that supports the windows and a cladding system based on Kingspan’s pre-existing 125 mm Benchmark system have also been developed.
There was a significant difference in building performance: The CIT buildings had an average U-value of 2.4 W/m2K and air infiltration levels were at 14.77m3/hour/m2, before the energy retrofit. The average U-value has come down to 0.36W/m2K and air infiltration is at 1.76 m3/hour/m2 at a pressure of 50 Pa following the retrofit. In addition, the retrofit has the potential to extend the lifetime of the buildings for at least another three decades.
As the pilot project is only a test-bed for the redevelopment of the original site, only 290 m2 was required out of the 19,190 m2 that the original buildings occupy. In fact, the project is exclusively designed in a modular fashion to offer ‘plug and play’ capability for research in building energy systems and in sustainable energy.
The target audience is primarily students and researchers but the target audience goes beyond that to include the college authorities whose aspiration is to create a zero energy campus by 2020. This project seeks to demonstrate than an increased capital investment in an energy retrofit can result in an estimated 75% reduction in operational energy consumption with the remainder being met by on-site renewable energy production.
Paul O’Sullivan, Project Leader and Lecturer, CIT School of Mechanical and Process Engineering
A major part of the project was the learning element to demonstrate to Undergraduate Students and Post-graduate Researchers the various energy efficiency and insulation measures carried out in a real-world setting in comparison to how they were to behave in theoretical surmise. In order to realize this, CIT used an array of wireless sensors delivered by Instrument Technology Ltd (ITL) to monitor CO2, relative humidity and temperature levels.
“We provided a wireless environmental monitoring system from Hanwell Instruments, which comprises a number of these sensors, a base station and the software needed to record data, monitor it, analyse it and to have an alarm system where necessary,” said ITL’s technical director Peter Keane, “The sensors are measuring temperature, relative humidity and CO2 levels and are currently producing 1,000 data sets.The sensors are placed inside and outside the building and are, for example, used for monitoring and comparing, say, the surface temperature on the inside and the outside of a quad-glazed window or for comparing the temperature of the surface of the first floor ceiling and the temperature of outer surface of the roof slab. Additionally, there are sensors within the composite walls measuring variances in temperature and humidity within the walls themselves.”
O’Sullivan informed that the sensors are specifically developed to be used repeatedly and flexibly. He said: “Even the sensors placed within the buildings walls are easily accessible and removable so that they can be reused in the future as we tweak the system we have developed, or as we test a completely new retrofit solution or for an undergraduate or postgraduate to use in a sustainable energy or a building materials research project.”
Energy Retrofit for Original Buildings
The refurbished area has been decoupled from the existing heating system with the area now heated by an air-to-water heat-pump fitted on the roof. The low-temperature hot water for the radiators is adequately warm for the occupants’ requirements because of the high-level of insulation. This is completely different from the poorly-insulated, draughty original buildings, which are served by a single radiator system operated on a time clock without any temperature controls in any of the blocks or in any individual space inside the blocks.
O’Sullivan added that as the energy retrofit is extended across the campus, the living lab will be able to integrate other renewable energy sources such as vertical wind turbines, a micro combined heat and power (CHP) plant and photo voltaic panels in due course.
The refurbished buildings are home to the Medical Engineering Design and Innovation Center (MEDIC) and The Centre for Advanced Manufacturing and Management Systems (CAMMS), the two CIT campus companies. Since this area is used for offices and not for lecture halls involving large numbers of students ventilation and CO2 build-up is not a major concern as it might otherwise be. The energy retrofit, however, does integrate natural ventilation that is controlled directly by the occupants with the glazing system fitted with manually-adjustable, insulated louvers that offer single-side ventilation.
The use of adjustable interstitial blinds helped reduce over-heating, including solar radiation and glare, in the summer. A separate set of louvers that enables purging of the structure with cold night air is also controlled by the BMS system. As a result, the temperature of the uncovered thermal masses in the refurbished spaces is also lowered.
ACE Control Systems have installed this BMS system. The company manufactures and designs state-of-the-art HVAC and building energy management systems with offices located in London, Dublin and Cork, where it is receiving most of its business from Irish companies that have expanded their operations into the UK because of the decline in construction activity in the country.
Noel Brennan, ACE Control Systems director, said, “This particular BMS had to work with a lot of third party interfaces and controls, so it had to be able to handle several different protocols. It is also fitted with an energy usage dashboard, which gives a very clear picture of how well the building is working.”
O’Sullivan said, “What we have founded is that continuing education is now a much more important part of energy conservation. Now that we are using far less energy heating the building, someone forgetting to switch of a desk lamp or a PC makes a real difference to the overall energy consumption figures!”
The project has been a great success so far. Kingspan Sales Director Ger Higgins said,“We’ve worked regularly with AMS over the years; in fact our relationship goes back a long way, developing integration of their window systems with our architectural panels. The Benchmark Karrier Panel System is a unique insulated panel that has been specifically designed and tested to support the Benchmark ranges of facades. The system provides excellent weather resistance, thermal, acoustic, fire and structural performance. The Benchmark Karrier Panel System is a metal-faced insulated panel that makes the building watertight, removing the façade from the critical path and enabling internal fit out to start sooner.
The system easily incorporates a range of facades which includes ceramic granite (which was used on this building), natural clay tiles, natural and pre-finished metals, colored and mirrored glass, cementitious boards and a range of natural and manufactured timber.
In addition to improving the performance of the building at CIT, I think the facade improves the look of the building architecturally, particularly the deeper reveals on the windows. We were delighted to work with a public body like CIT to develop a solution to reduce energy consumption and CO2 emissions. Refurbishment is likely to be a more viable and more cost effective alternative to complete redevelopment in the short to medium term.”
Originally, they were looking at fixing the new facade to the existing wall of the building – but the facade was too heavy for that to work so we designed a curtain wall system that was capable of supporting the window and the cladding system. The facade was installed by Wesco aluminium from Ballineen in West Cork and that company has been extremely impressed at the ease at which the system goes together to give a modern, clean look, but also a top-of-the-range sustainable energy-efficient facade.
Pat O’Hara, Sales Director, AMS
AMS was established in 1990 as Architectural and Metal Systems. With a staff of 110 people and has numerous patents covering innovations in window technology. The company invested in a 1,800 ton aluminum extrusion press, two years before which according to O’Hara made the company win many businesses overseas, especially in the manufacture of lighting and signage.
The Department of Education and Science has taken a keen interest in the CIT Zero2020Energy project, because the pilot can be extended across the entire CIT campus and it also offers the potential to be employed at eight other IoTs where the building stock is almost similar to that at CIT: i.e., they consist of four two storey buildings built between 1970 and 1977.
At a total cost of about £7.129 m (€9 m), these 36 buildings were constructed in 1969 prices, for what were then called the regional technical colleges (RTCs). These Institute of Technology buildings, built from uninsulated precast roof panels and concrete wall, with 6 mm clear single-glazing on the windows, pre-date the building regulations and feature ‘a very poorly performing thermal envelope with a very high level of air infiltration’.
They are cold and draughty in winter and overheat in the summer. As a result, they are expensive to heat and you wouldn’t be allowed to build them to their current standard today. And it is not just these IoT buildings, there are plenty of secondary schools that were built before the building regulations came into force and which are performing poorly.
The question is: what are you going to do with them? One option is to demolish and build again, but we have shown that retrofitting is an alternative, cheaper, solution.
In terms of returnon- investment, the savings made in the reduction in energy consumption and CO2 emissions is probably not enough to justify the capital cost of the retrofit – but when you consider that you are prolonging the life of existing buildings and avoiding the cost of building new ones, then the cost is quite justifiable.
Paul O’Sullivan, Project Leader and Lecturer, CIT School of Mechanical and Process Engineering
This information has been sourced, reviewed and adapted from materials provided byHawell SOlutions Ltd.
For more information on this source, please visit Hanwell Solutions Ltd.