Dual source heat pump with high seasonal performance factors, near

13kgs of R410a? Geez. Some countries are attaching huge levies to R410a with a view to economical phase out so I’m surprised R454b wasn’t used because this product won’t be around for long with that stuff in it (considering it’s a new product). What’s the nominal output? (13kg: 50kW?)

You could very easily achieve a similar result by venting EA just in front of the ODUs intake side. Does a similar job. Bear in mind the gains are slight. If a commercial office building needs 50kW to heat 500m2 (ish), the exhaust air is likely about 350 l/s (ish) for sufficient ACHs and FA per occupant (ish) whilst the ODU fan would need to pull something like 4,000 l/s (ish). So if you exhaust air at 20°C and the ambient air is -5°C, it might raise the temperature 2°C or so. Which DOES make a difference to efficiency, but if you look at those COPs they are not that impressive. HOWEVER: most heatpumps start needing to enter defrost cycles at approx 3°C which is kind of an averagely cold UK morning and where heatpumps dip in efficiency – using this feature in this condition you can delay the need for defrost slightly which is how to maximize the feature.

But you can achieve the result by building design rather than a patented product. (By the way, a long time ago I actually studied mech eng at the Uni of Hull myself. I now work as an engineer for a global HVAC manufacturer of heatpumps myself. x)