White Paper 2/5: The Heat Recovery Paradox

Heat recovery from exhaust air is one of the most effective energy measures available to property owners, and in most buildings it should be a natural choice. In commercial kitchens, it is often left out. That decision is usually well founded. Grease in the exhaust air clogs both the heat exchanger and the protective filter in front of it, leading to frequent filter changes, difficult cleaning and a real risk of downtime. For many, the investment simply becomes hard to justify.

Ozone and UV are often seen as part of the answer. In 2019, RISE tested both in a rig simulating a heavy grease load, measuring how much grease still reached the filter ahead of the exchanger. The effect was smaller than many had hoped: around 13 percent less mass load with UV and around 4 percent with ozone. At high grease loads, the researchers saw limited potential for these technologies alone to make heat recovery cost-effective.

In the second part of this five-part series, we look at why heat recovery is so often left out of commercial kitchen ventilation, what the research tells us about today's cleaning technologies, and the balance property owners have to strike between energy efficiency and robustness.

Read White Paper 2/5 →