BUILDING CASE STUDY EDUCATING ENGINEERS
Passive design elements: building envelope
• Size/mass • Built form • Shape • Materials • Ventilation • Location • Orientation etc
eg, user controls
eg,
automatic controls
Reactive design elements: building services
• Fuels • Type of systems • Size of systems • Plant controls • Plant effi ciency • Operating regime etc
eg, window controls
Human Factors
• Comfort requirements • Occupancy regimes • Management and maintenance
• Activity • Access to controls etc
Interactive elements
External factors, eg, climate
load while generating 450 kW of heat. The CHP is set to run only when the electrical tariff makes it cost effective to operate. Heat from the unit is fed into the main heating header. When heat is not needed, surplus heat is fed to the university’s swimming pool through the campus heat network. Additional heat for the hot water calorifi ers
comes from a small solar thermal system, installed as a teaching aide. ‘We looked at the possibility of meeting the hot water demand for 1,300 people entirely from solar, but it was not cost effective in Galway,’ Mooney explains. However, when combined with the CHP
unit, the solar system will generate suffi cient heat to meet the (reduced) summer hot water demand. In winter, the university’s 950 kW biomass
boiler provides the main source of heat for the air handling units, chilled beams, hot water calorifi ers and low-pressure hot water radiator system. The radiator circuit serving the teaching rooms and offi ces has been sized to run at a condensing temperature of 65C fl ow/45C return to maximise the energy effi ciency of the system. The biomass boiler is supplemented by
Key factors that infl uence energy consumption
In summer, these rooms will be naturally ventilated until the internal temperature rises above 25C, then active chilled beams with mechanical cooling will operate and maintain the room below 24C. In winter, the windows have been designed to open by 5% to supply fresh air, while the perimeter chilled beam units will supply heat. ‘From our dynamic thermal modelling I
think the space will be naturally ventilated for most of the year,’ says Mooney.
Heating strategy Unsurprisingly, heat for the building comes from a variety of sources. A 350 kWe gas- powered CHP unit meets part of the electrical
CIBSE branch Republic of Ireland
The CIBSE Republic of Ireland branch, chaired by Derek Mowlds and comprising an active and dedicated committee, delivers a number of additional services locally to CIBSE members in Ireland. The committee arranges
a host of interesting CPD events throughout the year in a number of locations, covering a wide range of technical and related topics in engineering and the built environment. The branch also promotes
32 CIBSE Journal January 2012
a philosophy of integration in design and, to that end, collaborates with other institutions on particular events, such as Green Building Week, with the Irish Green Building Council and the BIM awareness programme with CITA.
They host an annual conference in Croke Park, which attracts members nationwide, and includes speakers from the UK and further afi eld.
Recently, CIBSE Republic of Ireland collaborated with the Dublin Institute of Technology to publish the Journal of Sustainable Research and Design, which was formally launched on 24 November and is available for download at
http://eleceng.dit.ie/sdar/ SDAR_Journal_Sept_2011.pdf
For further information, visit
www.cibseireland.org or email
derek.mowlds@pmgroup-
global.com
two 1,048 kW gas-fi red boilers generously sized to enable them to take over from the CHP when it is being maintained. In addition, a geothermal system connected to bore holes provides heat to an underfl oor heating system in the building’s atrium. The cost of daytime electricity means the geothermal system will run solely at night to preheat the concrete fl oor. ‘In addition to the CHP and biomass
systems, we investigated as many sustainable systems as possible, but the payback for the technologies was beyond our fi ve-year threshold,’ Mooney explains. The building has been designed to use
about 54% less energy and to emit 37% less CO2 than similar buildings, based on CIBSE Guide F: Energy effi ciency in buildings. The students will be able to check the building’s performance through monitoring the power consumption of different electrical loads such as lighting, computing and HVAC equipment – which means that up to 1,100 students could be checking to ensure the building is performing as planned. CJ
● CIBSE Guide F: Energy effi ciency in buildings is available online to CIBSE members for free through the Knowledge Portal. It can also be purchased in hard copy (by both members and non-members) at a discount of 75% by using the code GVFJAN. A new edition of the guide will be published in the fi rst quarter of 2012. Visit
www.cibseknowledgeportal.co.uk
www.cibsejournal.com
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