Meaningful exploitation of waste heat

Energy consumption and CO2 emissions can be substantially reduced at the Bell sites in Oensingen and Zell. This is confirmed by what is known as "pinch analyses". The results of these analyses can be used to implement measures to enhance sustainability.

Where cold is generated, heat is automatically produced. A basic principle known to everyone who owns a fridge. In private households, very little of this heat is produced. Big cooling systems, on the other hand, generate a considerable amount of heat that can be meaningfully used elsewhere. For example, to heat up water for cleaning or to support the heating system. But first we need to know where and at what temperatures the heat is generated. A pinch analysis can help with this. As a systematic approach to improving energy consumption, it provides data about heat output and temperatures and uses the results to calculate the options for optimisation. This method was used to measure the heat output in Oensingen from May 2015 to July 2016, while the same tests were run in Zell until the end of 2016.

"Previously, we've seen from various studies that there's potential for improvement and savings at both manufacturing plants. With the pinch analyses, it is now possible to precisely identify the respective areas and implement the required measures," explains Roger Peier, project manager for Sustainability, Energy & the Environment at Bell. "The economic aspect isn't the only thing that's important to us. We can also improve the footprint of the plants in respect of environmental protection and resource efficiency – fully in keeping with the sustainability strategy of the Bell Food Group."

In Oensingen, the current use of the waste heat generated by the western chiller and the ventilation system was optimised during the course of the project. The analysis also identified other measures that could be sensibly implemented, such as building an additional CO2 heat pump to warm the domestic hot water to 90 degrees.

"The analysis in Oensingen confirmed the potential that was previously suspected," reports Roger Peier. "We can now use the available data to study the proposals and make sure that new acquisitions are precisely tailored to our local circumstances."

Before 2016, several conversion projects were carried out at Zell. When these were finished, the time was right for harmonising all areas by way of a system-wide pinch analysis. As the first measure derived from this analysis, a high-pressure heat pump was built in 2017. It uses the waste heat generated by the chillers to heat the water for the heating system to 90 degrees. The analyses were carried out by DM Energieberatung in Brugg. Bell's Sustainability team was responsible for the implementation. It worked closely with the plant managers, technical managers and heads of the Heating, Ventilation and Air Conditioning (HVAC) department.