Related EU Projects

This research project aimed to determine the heating and cooling potential of aquifer thermal energy storage (ATES) systems in the Mediterranean climatic zone. The project was carried out in greenhouses at the Cukurova University, Adana, during 2005-2006. For this purpose, two plastic greenhouses, each having an area of 360 m², were used. One of them was heated and cooled by an ATES system. In the second one, conventional heating and cooling systems were used. The inside and outside temperatures of the greenhouses, as well as ground water and exchanger water temperatures were recorded throughout the experimental period. Tomato crop was grown in both greenhouses and plant growth and fruit yield were measured. Energy costs of the greenhouses (fuel oil for the conventionally heated greenhouse and electricity for the ATES system) were also calculated. Consequently, these two systems were technically and economically compared.

The collected data showed that ATES systems have good potential for climatisation, both for heating and cooling, of greenhouses in the Mediterranean climatic zone. Between October 20^th and April 10^th, the inside temperature of the ATES system heated greenhouse was never below critical level (120 ℃) and thanks to this performance, the ATES greenhouse never used any fuel oil. On the other hand, temperature fluctuations in the ATES greenhouse were less than the conventionally heated one. The energy cost saving with ATES for heating was about 70% in comparison with the conventionally heated (with fuel-oil) greenhouse. With respect to tomato yield, the greenhouse that was heated by the ATES system resulted in approximately 20% more yield than that in the conventionally climatised one.

Turgut, B., Dasgan, H., Abak, K., Paksoy, H., Evliya, H. and Bozdag, S. (2009). AQUIFER THERMAL ENERGY STORAGE APPLICATION IN GREENHOUSE CLIMATIZATION. Acta Horticulturae, (807), pp.143-148.

In the year 2000, a system that uses solar energy in combination with Aquifer Thermal Energy Storage (ATES) was being designed. Its aim was to conserve a major part of the oil and electricity used for heating or cooling the Cukurova University, Balcali Hospital in Adana, Turkey. The general objective of the system was to provide heating and cooling to the hospital by storing solar heat underground in summer and cold in winter. As the main source of cold energy, ventilation air at the hospital and surface water from the nearby Seyhan Lake was to be used.

Paksoy, H., Andersson, O., Abaci, S., Evliya, H. and Turgut, B. (2000). Heating and cooling of a hospital using solar energy coupled with seasonal thermal energy storage in an aquifer. Renewable Energy, 19(1-2), pp.117-122.

The aims of this project were:

• To obtain practical experience from the establishment and operation of a low temperature heat storage system in a limestone aquifer, in connection with a district heating system; and
• To demonstrate the possibilities of commercial use of this type of aquifer in heating systems in combination with heat pumps.

The waste heat from a nuclear research reactor was used as a heat source for a 2.2 MW heat pump that was connected to a district heating system. The temperature of this waste heat was between 40°C and 45°C. However during normal operation, approximately three times as much waste heat was available as it could have been utilised by the heat pump. The nuclear reactor used to close down for 5 days every 4 weeks and during this period heat was being supplied by the combustion of oil. The idea was to store surplus heat from the reactor in a limestone aquifer and extract this heat during periods of reactor shutdown. Two main wells 100 metres apart were used, one for injection of the heated water, and the other one for extraction. The extracted water was expected to be at a temperature of around 30 °C. Two further wells were drilled for measurement purposes and equipped with temperature and pressure transducers that were connected to a computer system.

In this project, the extension of the existing cooling capacity was realised with an Aquifer Thermal Energy Storage (ATES) instead of a conventional chiller. Compared with a chiller, the use of ATES reduced the electricity consumption for cooling by 50%. Moreover, the heat that was extracted from the ventilation supply air in summer was stored in the aquifer to be utilised in winter for (pre)heating ventilation air. The integration of the ATES system in the installation with 2 chillers enabled also short-term cold storage in summer. Therefore, the risk of cold shortage due to climatic influences (warm summer and/or mild winter), was compensated for without costly investments in extra chiller capacity. Furthermore, the combined use of the aquifer system for seasonal cold and heat storage, as well as short-term cold storage made the system more profitable. Consequently ATES can also be attractive for smaller projects with existing cooling systems that have to be extended. Therefore, this will enlarge the market potential for ATES. For instance, in the first half of summer 1994 (April, May, June and July) the storage delivered 256 MWhth (megawatt hours of heat) cold and 82,000 kWhe (kilowatt hours of electricity) were saved. No additional cooling was applied thanks to the lower temperature in the cold storage.

The project demonstrated:

- That the required extension of the cooling capacity in the hospital can be realised by storage or "winter cold" in a sand-layer (aquifer) in the soil, and that such a storage system can be integrated in the existing cooling system.

- The technical and economical feasibility of combined seasonal cold and heat storage in an aquifer for cooling and (pre)heating ventilation supply air.

- And the advantages of using the aquifer for short time storage of cold that is loaded at night with the available chillers, thus creating extra facilities for energy management and compensating for risks of cold shortage due to climatic influences.