Saint-Gobain Gyproc Bålsta TIPCHECK

Two objectives with TIPCHECK: reducing energy consumption and CO2 emissions

Gypsum plants can be extremely energy-intensive like most manufacturing industries. Insulation is an effective solution to optimize energy-consumption, and at the same time relatively easy to implement. In addition, thermal insulation not only reduces our energy consumption but also the corresponding greenhouse gas emissions.

Like other Saint-Gobain entities, such as Saint-Gobain PAM, GYPROC has decided to reduce its own environmental impact thanks to the TIPCHECK energy auditing tool, by implementing  the best thermal insulation for its  plant in Bålsta (Sweden).

The objective of this TIPCHECK energy audit, conducted by Saint-Gobain ISOVER certified TIPCHECK engineers, was to determine the energy losses of the dryer and its surroundings (hot air feed).

Heat losses in the dryer

Burners warm up air which is then pushed through the air duct system to the dryer. Inside the dryer this air is heating up the gypsum boards in order to evaporate the water content inside the product.

Dryer (walls and bottom)

On the walls, there two different situations were observed:

• Well insulated doors/hatches
• Poorly insulated or uninsulated structure

For doors and hatches, the insulation may be left as it is, except in some areas where the insulation has been removed for maintenance and not replaced as per design conditions.

Detail after maintenance (Zone 1, right)

Detail before maintenance (Zone 1, left)

The whole structure around each of the ‘doors’ (64 per side) proved to be uninsulated. The space between doors is in principle small, but is a real thermal bridge*. When summing up the total surface area this represents - almost 30 m² – we quickly understand that this cannot be neglected.

Same reasoning for the large bolts: there are 144 bolts in all, with a total radiative surface of 3m² and a fairly high temperature (around 90 ºC).

The bottom part of the dryer is also poorly insulated or completely uninsulated which is why heat losses through the bottom of the dryer appear to be quite high.

Detail bottom part of the dryer

Air duct system and burners

The whole duct is insulated with 150 mm of stone wool (80 Kg/m3 is assumed for the calculations) in three layers of 50 mm. The duct itself is well insulated and no major losses were detected.

There is nevertheless a good opportunity for improvement by insulating all the compensators, currently uninsulated.

Detail of duct compensator

The burners are already insulated, but they still show a fairly high surface temperature. This could be improved by installing insulation on top of the burners.

Detail of the burners

Transforming energy loss into energy saving

As a conclusion of this TIPCHECK audit, the following annual savings potentials offered by better technical insulation could be highlighted:

The insulation solutions offered by Saint-Gobain ISOVER (using mainly U TECH Roll 4.0) have the right balance between investment and savings :

• Investment costs (SEK): 1.194.064 (€ 108.424)
• Expected payback: between 8 and 9 months

The analyzed dryer and ducts will be upgraded in 2023. This has been validated and included in the plant’s technological budget.

* A thermal bridge is an area where the heat transfer is higher than in the surrounding areas