Authors: Magdalena Hajdukiewicz, postdoctoral researcher and adjunct lecturer, and Jamie Goggins, senior lecturer and chartered engineer, NUIG
Energy provides safety, comfort and mobility to people and is essential for industrial, commercial and societal growth. However, generation and consumption of energy emit greenhouse gases and various air pollutants, and issues such as waste generation and oil spills are associated with various fuels. All of those factors have a negative impact on the natural environment and global climate.
Human-induced climate change is occurring globally and has already made a significant impact on the environment and society, due to increased levels of greenhouse gases. The building sector is responsible for 40 per cent of total final energy consumption and 36 per cent of total CO2 emissions in the EU [1].
In Ireland, primary energy use in the building sector is associated with heating/cooling and lighting of buildings. In 2011, energy use in buildings accounted for 41 per cent of primary energy supply in Ireland [2].
On May 19, 2010, the European Union (EU) adopted the Directive 2010/31/EU [3], which aimed to reduce energy consumed by buildings. Member states are requested to adopt a methodology for calculating the energy performance of buildings (energy performance certification). The objective of the Directive 2010/31/EU is to ensure all new buildings are almost zero-energy consumption buildings by the end of 2020.
In order to meet the requirements posed by the EU and, thus, reduce the environmental impact of buildings, energy efficient measures must be taken into account when designing new and retrofitting old buildings. Reducing energy consumption and CO2 emissions in buildings through energy efficient technologies (particularly ensuring satisfactory thermal performance of building fabrics) would significantly reduce primary energy consumption by buildings.
The building fabric is the envelope of the building which includes walls, floors, roofs, windows and doors. The choice of the building fabrics strongly influences the quality of indoor environments. A proper design of the building envelope minimises the heat loss and maximises the use of solar heat gains on cold days, while maintaining the building cool on warm days.
Thermal mass can be an effective solution in delivering optimal indoor conditions in buildings, by reducing indoor temperature fluctuations. Moreover, when combined with other energy efficient solutions, such as a passive solar design, thermal mass can significantly reduce the energy consumption in buildings.
Concrete is a long-lasting building material that does not require any maintenance, replacement or application of toxic paints or preservatives. Moreover, the thermal capacity of concrete leads to thermal stability and thus offers considerable energy savings and good quality of indoor environment. Hence, concrete is the primary construction material in most of the sustainable developments in Europe [4].
According to the Irish Concrete Society and Irish Concrete Federation: "Exposed concrete acts as a thermal moderator preventing rapid thermal swings, greatly reducing the need to cool office buildings, which is typically the biggest running cost. Only 10 per cent is related to the construction of the building. Designing with energy in mind can reduce in-use energy costs by up to 75 per cent and greatly reduce carbon dioxide emissions [5]."
The need for new solutions to control the environmental and energy performance of energy efficient buildings led to the collaboration between the National University of Ireland (NUI), Galway and the small medium enterprise (SME), Oran Pre-Cast Ltd. based in Oranmore, Galway. Oran Pre-Cast is one of the largest and most progressive indigenous pre-cast manufacturers in Ireland.
The company manufactures quality precast concrete products for industrial, commercial and domestic applications, guaranteeing the highest standard of their structural and environmental performance. The Informatics Research Unit for Sustainable Engineering (IRUSE) at NUI Galway is the research group providing a unique expertise in the multidisciplinary area of energy efficiency in buildings, focusing on different aspects of energy simulation, building information modelling (BIM) and novel measurement frameworks.
Through the expertise in precast manufacturing process and numerical simulation (whole building simulation, computational fluid dynamics, reduced order modelling), access to the demonstration buildings, live weather monitoring [6] and access to high-end structural and environmental laboratories (Engineering Building at NUI Galway [7]), IRUSE and Oran Pre-Cast provide the complete real-time, experimental and numerical data sets describing structural and environmental performance of buildings and building components, e.g. [8].
Oran Pre-Cast manufacturing process allows for mechanical and electrical products to be embedded in the structure. Oran Pre-Cast and NUI Galway have vast experience in embedding structural (electrical resistance and vibrating wire strain gauges) and environmental (thermistors) sensors in its precast systems, both at the precast manufacturing and in situ stage.
Two industrial scale demonstration buildings (Engineering Building and Institute for Lifecourse and Society at NUI Galway) provide real-time monitoring of the structural and environmental performance of Oran Pre-Cast prefabricated systems.
Combining building information modelling (BIM), structural/energy/environmental simulation results and physical measurements from the sensors embedded in the operating buildings (Figure 1), allow investigating structural, thermal, acoustic and air tightness properties of the building structure and control their influence on indoor environments.
This is done with a motivation of (i) better prediction of indoor environmental conditions; (ii) healthier, more comfortable and productive indoor environments; and (iii) reduced/optimised energy consumption in buildings.
[caption id="attachment_22819" align="alignright" width="300"]
Figure 1. Overall methodology for the research collaboration[/caption]
It is vital that consideration is given to the structural, environmental and energy aspects in operating buildings. This should be done through the combination of the advanced building design tools, high technology manufacturing processes and ‘real-time' monitoring in operating buildings, leading to safe, healthy and comfortable environments for the occupants of energy efficient and sustainable buildings.
*The collaborative research between NUI Galway and Oran-Precast Ltd. has been funded through:
- Irish Research Council and Oran Pre-Cast Ltd. Enterprise Partnership Scheme (2013-2015);
- European Commission Horizon 2020 programme (2015 – 2018) as part of the Built2Spec project ‘Tools for the 21st century construction site’.
For more details contact:
Dr Magdalena Hajdukiewicz. Email:
magdalena.hajdukiewicz@nuigalway.ie or Dr Jamie Goggins. Email:
jamie.goggins@nuigalway.ie
References
[1] EU, “Official website of the European Union,” 2014. [Online]. Available: http://www.europa.eu.
[2] SEAI,
Energy in Ireland 1990-2011. Dublin, Ireland: Sustainable Energy Authority of Ireland, 2012.
[3] European Commission, “The Directive 2010/31/EU of the European Parliament and of the Council of 19 May 2010 on the energy performance of buildings,” Official Journal of the European Union, 2010.
[4] IPCA, “Precast concrete: Frames guide,” Dublin, Ireland: Irish Precast Concrete Association, 2005.
[5] ICS and ICF, “The new concrete standards: An introduction to EN 206-1,” Drogheda, Ireland: Irish Concrete Society and Dublin, Ireland: Irish Concrete Federation, 2004.
[6] IRUSE, “IRUSE weather website,” 2014. [Online]. Available: http://weather.nuigalway.ie/.
[7] NUI Galway, “Engineering Building,” 2012. [Online]. Available: http://www.nuigalway.ie/new-engineering-building/.
[8] M. Hajdukiewicz, D. Byrne, M. M. Keane, and J. Goggins, “Real-time monitoring framework to investigate the environmental and structural building performance,”
Build. Environ., vol. 86, pp. 1–16, 2014.