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Case: Recapturing excess heat from a food production unit


Food production units often have large air flows with high temperature in the process air. In order not to risk costly downtime due to clogging, recycling and reuse of excess heat in the exhaust air is often not carried out. However, if you succeed in recovering this waste heat, it can be returned as a supplement to ventilation, hot water or other process-specific heat-demanding equipments.

The challenge

Preventing heat waste is a great way to reduce the heating cost and lower CO2 emissions from production facilities in the food industry. But, until now, high concentration of grease, soot and moisture in the excess air has made it impossible, or at least, very expensive.

The solution

Lepido is an industrial heat exchanger, developed and built in Sweden. It can recapture excess heat from
the ventilation in industrial processes. The patented set up of coils allows the particles (and the hot air) to
pass through the heat exchanger without getting stuck.


In this project, the Lepido was installed as part of the exhaust air duct, where the air stream is heavily contaminated with soot and grease due to the duct serving the high-intensity production line. The recovered heat is fed back to the supply AHU serving the production line via a run-around heat exchange circuit, which means there is no risk of transfer of odours, or of the heat exchangers clogging up with particles.

Project data

This data is based on a project delivered in 2022. It is a food production unit, and the recaptured excess
heat is returned to the production facility supply air. 

Type: Production unit for food production
Airflow: 9,7 m3/s
Air temp: 40°C
Pollutants: Grease, soot & moisture
Return: 9,7 m3/s supply air to production facility
Model: 2 x L50 (1100x1800x900 mm)
Set temperature: +16°C
Need: 355 kW
Operating hours: 20 h/day
Energy need: 616 600 kWh/year
Lepido Heat exchange effect: 288 kW
Energy recovery: 614 900 kWh/year


The recovered excess heat in this project covers 99% of the demand for heat in the production facility. Annual energy savings is 614 900 kWh per year.

The building parameters also allowed the Lepido solution to offer great installation simplifications as the energy recovery functionality could be decentralized from the main technical room – saving vast stretches of both ducting and piping installations. The possibility to place the Lepido close to the actual production line also greatly simplifies maintenance, reducing time and cost.

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Exhibit : Graph showing the recovered energy in green and the total required energy in red – Lepido covers 99% of the required energy for this site

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Exhibit: Service hatches installed before and after the heat exchanger

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Exhibit: Drain connection, removing water both from condensation during operation and any excess water used during cleaning/maintenance