Heat recovery systems
Heat recovery is the re-use of waste heat arising from a production process that would otherwise be lost, and which allows reduction of energy consumption. AGC Glass Europe has so far installed heat recovery systems in four plants.
Cuneo (Italy) and Osterweddingen (Germany)
At its Cuneo plant (Italy), AGC Glass Europe invested in an electric power generation system with the aim of reducing indirect emissions of CO2 and also lowering costs for electricity. The system generates power by taking the waste heat of the flue gas from the glass melting furnace and converting it into electricity. This works via an Organic Rankine Cycle (ORC) module that uses organic oil with a low boiling point (instead of water as in a steam turbine generator). The system produced 7088 MWh in 2019.
Our plant in Osterweddingen (Germany) is also equipped with a heat recovery installation. This installation produces electricity and steam, both being reused in the plant. The system produced 10,529 MWh in 2019.
The Roccasecca plant (Italy) is equipped with a heat recovery system for heating its warehouse.
This system recovers the heat from waste hot air from a cooling tunnel located nearby the warehouse. Compared to other solutions (e.g. conventional heaters), this system avoids any additional gas consumption and so has no impact on the total amount of CO2 emissions released by the plant. This system makes it possible to recuperate about 580 MWh per year.
Heat recovery from the lehr at f|glass for greenhouse
Since December 2017, f|glass supplies its waste heat to the neighbouring greenhouse. The waste heat from the closed cooling circuit from the furnace, the tin bath and the steam turbine cooling is supplied to the greenhouse. Heat exchangers were installed and an 800 m pipeline was laid. f|glass supplies an average of 8 MW of heat at 52°C. The main technical challenge was to install the heat exchanger without disrupting the continuous glass production.
By passive delivery of heat to the greenhouse, thermal energy will be withdrawn from the closed cooling circuit, especially in the winter months. It also helps to reduce the running time of the ventilators of the FinFan which in turn cuts energy consumption.
With a view to continuously improving the ecological footprint of glass production, there are other projects planned related to the greenhouse. These include rainwater collection and supply (potential of up to 33,000 m³ rain water from 70,000 sq.m roof) and supplying gaseous CO2. In addition, heat recovery from the annealing lehr is planned for the future.
Cogeneration unit at Fleurus plant (Belgium)
The Fleurus automotive glass plant (Belgium) installed in 2013 a gas-fired cogeneration unit which produces two types of energy: electricity and heat. This system has energy efficiency of more than 90%.
The gas consumed by the co-generator is used 36% for electricity production, 32% for heating water, 18% for heating oil at 220°C, 2% for hot air production, and 2% for pre-heating de-ionised water.
Each of these “by-streams” is utilised in the plant itself. For example, electricity is used for mechanical power and lighting, hot water goes to the washing machines, and heat oil is used within various processes such as the autoclave, the PVB stretching, the back furnace, etc.
Thanks to this system, the Fleurus plant saved around 320 tonnes of CO2 in 2019.
More and more plants installing photovoltaic panels
AGC Glass Europe is committed to in-plant electricity generation through the installation of photovoltaic (PV) panels.
The first photovoltaic panels were installed at the Osterweddingen plant (Germany) and Cuneo plant (Italy) in 2009 and 2010. Since then, other photovoltaic projects have been introduced at many other sites. In 2018, AGC Glass Europe boosted its capacity by 1,200 kWp (an increase of 16%) by installing two additional large-scale PV panels at the Lodelinsart plant and Technovation Center. The total output of the photovoltaic installations reached 9,509 MWh in 2019.