The project consists in recovering the heat contained in the exhaust air emitted by the exhaust nozzles of three annealing furnaces of a plant belonging to a well-known hollow glass production brand. This heat is used for the winter air conditioning of the automatic inspection department and of the executive and administrative offices and for cooling by means of a brand new absorption chiller a large electrical panels room.
To obtain recovery, three air-termination systems have been created, one for each furnace, each consisting (mainly) of an air/water heat exchanger. Through the heat exchangers, the heat contained in the exhaust air emitted by each oven is used to heat a flow of water in a closed circuit from 70 to approx. 85°C. The heated water supplies the heating terminals installed in the departments involved in the intervention.
The intervention aims to generate a saving of natural gas equal to the total demand in fact for heating the rooms described, the customer decided not to adopt standard heat generators, opting for a solution with heat recovery. Furthermore, part of the hot water produced thanks to the heat recovery system created is used to supply a lithium bromide absorber with a cooling capacity of 70 kW. Thanks to this last equipment it is now possible to cool a large electrical panel room at zero cost.
Results obtained:
- Thermal energy saving: 3.650.000 kWh/year
- Electrical energy saving: 200.000 kWh/year
- Primary energy saving: 376 Toe/year + 37 Toe/year
- Saving of natural gas: 450.000 scm/year
- CO2 not released into the atmosphere: 877 tons/year + 86 tons/year
- Payback intervention: about 24 months
The system has been equipped with a monitoring system able to measure and historicize the post-intervention consumption. This is essential for taking stock of and verifying the energy savings achieved.
The intervention has been analysed, designed and implemented by RENOVIS.