Objective
This project demonstrates the technical and economic feasibility of using solar energy as a source of heat for industrial water required at 70 deg C for washing sheets of glass in a laminated safety glass production line. Covering two shifts, about 14 000 litres of water are used. The energy savings are estimated at 9 TOE per year and the payback time is 8 years (or on a 15 year life cycle basis, the energy produced is cheaper than electricity).
Water used in the glass washing process was heated by resistance heaters. The system under investigation uses high efficiency CORTEC solar collectors which have a number of advantages in this application:
-much higher heat output than that plate collectors at all operating temperatures, and an estimated 69% efficiency at an operating temperature of 70 deg C.
-a reliable source of energy; essential to any industrial process
-satisfactory resistance to weathering and chemical agents due to the pyrex glass pipes which make up these collectors.
In this application the innovation is in the use of this type collector for an industrial process. Regarding the hot water requirements, a number of assumptions regarding the dimensions of the plant have been advanced, bearing in mind the following points:
- during the month of August, the solar plant cannot be used, because the factory is closed for annual holidays.
- to avoid the solar plant being over-dimensioned for the summer period - thatis, to avoid most of the energy captured during the summer months being wasted - the design ensures that the solar energy supplies only a percentage, albeit high, of the annual energy requirement. Obviously, during the winter months, the plant will in any case only provide the energy needed for pre-heating the water.
- the user requires hot water five days a week.
- in order to design the heat storage system correctly, account therefore had to be taken of the need to store the energy captured during non-working days (Saturday and Sunday).
A small storage system would result in the water becoming too hot.
On the other hand, too big a storage system would not produce the desired temperature; moreover, it has to be remembered that such plant would also cost more.
This configuration supplies 30-40% of the required energy from November to February and 100% in July.
- Cortec solar collectors with vacuum-sealed pipes, selective surface installed at ground level on a concrete plinth.
- Thermally-insulated, 10 000-litre thermal storage, consisting of two 5 000-litre tanks.
- Plate-type heat-exchanger.
- Pumping group, consisting of twin electro-pumps, complete with intercepting and filtering equipment.
The estimated "turnkey" cost of the above, is estimated at lit. 90 mil
Topic(s)
Call for proposal
Data not availableFunding Scheme
DEM - Demonstration contractsCoordinator
20123 Milano
Italy