Designed to Lead Built to Last

Process Heat Recovery

Glasgow Waterfont Buildings ventilated by SigmaEPD

Sigma Heat Recovery

Commercial and industrial processes use a large amount of heat energy. During these processes heat energy is extracted and dumped into the atmosphere along with unusable gases.

This energy can be reused to heat auxiliary processes and spaces. The patented SigmHRV system can recover and reuse energy that would otherwise be lost. The heat exchanger is able to perform in harsh commercial and industrial environments such as kitchens and processing plants without clogging.

The systems are bespoke to meet the needs of individual clients.

Process Description

The SigmaHRV operates on a counter-flow principle i.e. Dirty air is extracted from the process and passed through sealed passages in the heat exchanger. At the same time fresh cold air is also passed through adjacent passages.

The hot air stream gives up heat to the cold air stream. The dirty cooled air is exhausted to atmosphere. The fresh heated air is used in other parts of the process. Both air streams are made to flow counter to each other along a torturous turbulent path without cross contamination.

Core Benefits
  • In this trial the heat exchanger was able to rise outside air temp by 20°C-30°C degrees
  • Energy Saving
  • Money Saving
  • Smaller temperature fluctuations
  • 100% fresh air (This unit has a processing capacity in excess of 4000m3/h see data attached)
Patented Technology
  • Food Processing
  • Industrial Processes
  • Smoking rooms
  • General ventilation
  • Commercial Kitchens
  • Counter flow heat recovery
  • Anti-clogging
  • Self-cleaning
  • Low fouling rate


Devro (Scotland) Ltd have an ongoing commitment to reducing our environmental impact through reduction in our energy consumption.

We have been working with Sigma Engineering over the last year to trial a heat recovery unit on a process application at our Moodiesburn site. The trial was put in place to evaluate not only the heat exchanger performance but also to see how it coped with our waste heat stream that is laden with oils. We have tried on many occasions in the past to utilise this waste heat. However, all normal heat exchangers fouled up within weeks of installation.

The current trial has been ongoing since summer 2010 and therefore has seen both summer & winter conditions. We have installed on-line monitoring to our BMS system which has shown throughout the trial that the heat transferred has not changed significantly at around 10 kw. It has also shown that the heat transfer surface has not fouled significantly. We are now looking at a full project design.

Jim Goodwin

Facilities Project Engineer
Devro (Scotland) Ltd

Devro PLC