- First large commercial “urban turbine”
- Energy generatedby wind turbine stored in the form of ice
- Received a Royal Institute of British Architects award for architectural excellence
- 191,000 sqft. facility
- Historical structure
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Built in the late 1960’s the PJ Carrol Building, on the Dundalk Institute of Technology (DkIT) campus, in Dublin, Ireland, originally opened in 1970 serving as a cigarette factory. This historical and architecturally protected factory building is said to be one of the finest examples of Miesien architecture in Europe. The factory consists of 191,000 sqft, 118,000 sqft of which was refurbished in 2010 when DKIT purchased the structure to facilitate a college expansion project. The large factory area would be air-conditioned by ice-based thermal energy storage in order to make more efficient use of an on-campus wind turbine.
“This installation provides the perfect example of how buildings can be used to even the peaks and troughs created on the national grid by the addition of wind resources,” said Edel Donnelly, Building Services Engineer at BDP.
This case study shows that energy storage can help smooth out the electricity grid demand profile and allow more renewable wind energy to be available to the grid.
Due to increases in student population and energy consumption, DkIT was facing rising utility expenses and quickly approaching its maximum electrical capacity. These factors inspired a plan to incorporate renewable energy into the campus’s power generation. In 2005, DkIT commissioned the first large commercial “urban turbine” in Ireland and the first large commercial wind turbine on a college campus in the world. Wind energy would produce zero polluting emissions and capitalize on an inexhaustible resource. Ireland is known to have one of the best natural resources available in Europe in terms of wind generation potential and is currently producing about 10 percent of its electrical energy needs from wind. However even though wind in Ireland is bountiful, the inconsistent nature of wind resources meant that excess electricity was being wasted when demand was lower than the energy produced. During times of peak demand the energy generated by the turbine was not sufficient to meet the needs of the college. Alternatively, potential savings existed if the campus could address the underutilized wind turbine power generation at night.
With the campus nearing maximum capacity, DkIT needed a solution that could store excess energy to even load factors, reduce utility costs and provide micro-grid stability and utilize the night load, while maintaining the historical integrity of the PJ Carroll Building.
During the design process the Building Design Partnership (BDP), an international, interdisciplinary practice of architects, designers, engineers and urbanists, recommended the use of CALMAC’s IceBank® energy storage technology in order to smooth the load curve that was fluctuating from the inconsistent addition of electricity from the wind turbine.
“The installation went without any problems. The start up and testing was also quite smooth. BDP’s recommendation to take advantage of capturing excess wind energy by using CALMAC’s IceBank® tanks has really helped to maximize the use of renewable energy on campus,” said Christian Maas, Building Services Technical Officer at DkIT.
The thermal energy storage tanks provided a way for the campus to capture the excess energy from the renewable energy resource that up until that point had been wasted due to a lack of demand. With the energy storage and chiller cooling units installed in an underground room adjacent to the building, the architectural integrity of the building remains intact.
Excess wind energy that is created by the campus turbine gets stored in the thermal energy tanks in the form of ice. If there is excess wind energy the chillers can run day or night and recharge the IceBank tanks as necessary. Full charge of the energy storage, while not necessary to cool the building, takes four hours. If the building management system detects that there is sufficient available electricity from the wind turbine and the IceBank tanks require charging, the chillers can run during the day and at the same time charge the energy storage tanks. On the other hand, if the campus electrical demand increases to the point where there is insufficient wind energy and the tanks need charging, the building management system enables control routines that allow the heating and cooling temperature set points in rooms to decrease or increase and therefore consume less energy and avoid a utility fine for the college.
“The installation went without any problems. The start up and testing was also quite smooth,” said Christian Maas, Building Services Technical Officer at DkIT. “BDP’s recommendation to take advantage of capturing excess wind energy by using CALMAC’s IceBank® tanks has really helped to maximize the use of renewable energy on campus.”
According to Edel Donnelly, Building Services Engineer at BDP, “this installation provides the perfect example of how buildings can be used to even the peaks and troughs created on the national grid by the addition of wind resources.”
The wind turbine generated 40% of the campus energy requirements, which included 16% of the Carrol building’s load including the air-conditioning system. While the amount of wind energy generated is substantial, due to its intermittent nature, the wind resource is not always available to match the peak grid loads. Add the fact that the air conditioning system was calculated to represent 45% of the anticipated electrical loading in the Carrol building and you have a real challenge with how best to manage the fluctuating renewable energy supply so that occupants are kept cool and comfortable at all times.The incorporation of thermal energy tanks solved the problem of meeting peak grid loads consistently by storing the wind energy.
With energy storage and wind energy, DkIT was able to lower the campus’ dependence on traditional energy resources such as coal by almost 50%. Consider that coal accounted for 45 percent of total energy-related CO2 emissions worldwide in 2011. Lowering use of fossil fuels is an important component of any energy management strategy. In addition to lowering the environmental impact, thermal energy storage lowered energy costs. From August 26, 2011 to May 14, 2012, DkIT was able to save nearly 8,000 dollars over using a non-energy storage system.
Calculations have revealed that the wind turbine in combination with the IceBank energy storage tanks can cover 96 percent of the chiller load.4 Cooling demand within the building is lower than originally simulated and the thermal energy storage tanks are able to meet demand without reaching full capacity. With 64,000 sq.ft. still unoccupied, the utilization of energy storage is projected to increase over the next couple of years.