Russdl Posted March 1, 2020 Share Posted March 1, 2020 Has anyone heard of these Komfovent MVHR units? Does anyone have any experience of them? https://www.komfovent.com/en/business/rhp/ They have a Rotary Heat Exchanger, I've never heard of that before but they sound quite clever but is it really just one more thing to go wrong? Plus a little bit of cooling/heating. What does the collective wisdom think of these units? Link to comment Share on other sites More sharing options...
dpmiller Posted March 1, 2020 Share Posted March 1, 2020 BPC have started selling them so they must be OK. Rotary is normally used in big commercial units Link to comment Share on other sites More sharing options...
Jeremy Harris Posted March 1, 2020 Share Posted March 1, 2020 Rotary vane heat exchangers are common in larger, commercial, heat recovery systems. They can work well, but don't tend to outperform other types of heat exchanger. It looks as it these units have a heat exchanger efficiency of 80%, plus a heat pump, a bit like the Genvex unit we have. Our Genvex uses a plate heat exchanger, with an efficiency of about 88% (varies from ~83% to ~92%) Link to comment Share on other sites More sharing options...
Russdl Posted March 1, 2020 Author Share Posted March 1, 2020 Just now, dpmiller said: BPC have started selling them That's where I first saw them, I thought they were very reasonably priced until I dug deeper/scrolled further and actually looked at the price of the RHP model which is quiet reassuringly expensive. Link to comment Share on other sites More sharing options...
Russdl Posted March 1, 2020 Author Share Posted March 1, 2020 1 minute ago, Jeremy Harris said: They can work well, but don't tend to outperform other types of heat exchanger. There blurb says that one of the benefits of the Rotary Heat Exchanger is that it won't freeze up even at -30 outside which means the unit doesn't have to defrost and let cold air past the heat exchanger in the process. Link to comment Share on other sites More sharing options...
Jeremy Harris Posted March 1, 2020 Share Posted March 1, 2020 No combined MVHR and exhaust air heat pump should ever freeze up, really. Certainly our Genvex doesn't, and that uses a normal plate heat exchanger. It's really hard to see how any heat exchanger could ever get both cold enough, and moist enough, to freeze up, as it's always being heated by the outgoing air from the house, which will typically be well over 20°C. Incoming air that's well below freezing will also be pretty dry, as most of the water vapour will have already condensed out. Hitting the warmed heat exchanger isn't going to cause any small amount of residual water vapour to condense. Link to comment Share on other sites More sharing options...
Russdl Posted March 1, 2020 Author Share Posted March 1, 2020 @Jeremy Harris How do the 'specs' of the Komfovent compare to your Genvex? Are they much the same? Link to comment Share on other sites More sharing options...
Jeremy Harris Posted March 1, 2020 Share Posted March 1, 2020 Just now, Russdl said: @Jeremy Harris How do the 'specs' of the Komfovent compare to your Genvex? Are they much the same? The Genvex we have is the GE Premium 1L, which has the following spec: GE PREMIUM 1 1L Iss 7.pdf The closest Komfovent unit to this seems to be the RHP 400, but the data sheet seems a bit sparse: RHP_400_V_EN.pdf The prices seem roughly similar, at around £5k, from what I've been able to glean from a quick search. Link to comment Share on other sites More sharing options...
Stones Posted March 1, 2020 Share Posted March 1, 2020 I do know someone who fitted a 'domestic' rotary unit (not sure of make). They really struggled to see anything above 60% efficiency, and no end of tinkering with control settings helped. They had been steered down that route on the basis of the larger air handling capacity of the rotary unit compared to a fixed HE core. 1 Link to comment Share on other sites More sharing options...
Russdl Posted March 1, 2020 Author Share Posted March 1, 2020 7 hours ago, Jeremy Harris said: The prices seem roughly similar, at around £5k So it would seem to be a similar product but without the ‘name’ for similar money. That makes one wary. Thanks for the feedback. 8 hours ago, dpmiller said: BPC have started selling them so they must be OK Does one follow the other? I know BPC have a good reputation here. Link to comment Share on other sites More sharing options...
Eric Posted June 13, 2020 Share Posted June 13, 2020 @Russdl did you go for a Komfovent unit? I have just received a quote from BPC for a new build & it’s for a Komfovent R500. I can’t find much information on them, they look fairly industrial! The unit is huge, heavy & has 250mm ducting. Link to comment Share on other sites More sharing options...
Russdl Posted June 13, 2020 Author Share Posted June 13, 2020 @Eric I’m still sat firmly on the fence however the unit I was looking at was the RHP 400 V which sounds like an altogether different machine to the one you are describing. Information on the RHP 400 V is not exactly voluminous it has to be said. Link to comment Share on other sites More sharing options...
joth Posted June 14, 2020 Share Posted June 14, 2020 Side comment: during the current pandemic the recommendation is to turn off recirculating ventilation systems and any using rotary heat exchangers, due to a minute risk of a virus being transferred from the extract to the inlet feed via the rotor. Normal heat exchangers (including enthalpy exchangers) are fine. These rules are all for large commercial buildings, fairly irrelevant for a single home but I found it interesting anyway. 1 Link to comment Share on other sites More sharing options...
PeterW Posted June 14, 2020 Share Posted June 14, 2020 22 hours ago, Russdl said: @Eric I’m still sat firmly on the fence however the unit I was looking at was the RHP 400 V which sounds like an altogether different machine to the one you are describing. Information on the RHP 400 V is not exactly voluminous it has to be said. Most of the documentation is online here https://www.komfovent.com/en/product/rhp-400-v-2/ Not sure if its clear if it comes with or without the separate controller..?? Lossnay does a similar thing - you can either control it in a "dumb" way using NV switching or use one of their controllers. Link to comment Share on other sites More sharing options...
Adsibob Posted January 24, 2021 Share Posted January 24, 2021 On 01/03/2020 at 08:42, dpmiller said: BPC have started selling them so they must be OK. Rotary is normally used in big commercial units I asked BPC to quote me for a MVHR system for my home and I was offered a Vent Axia Sentinel Kinetic Plus B or a Komfovent Domekt R-450-V. The former has a 5 yr warranty and the latter only has a 1 year warranty. Ever since a mate at management consultancy McKinsey told me that his job was to advise companies how to save money by reducing the longevity of their components so that the machine they manufactured failed shortly after the warranty period expired, I've placed a lot of weight on the warranty period of anything I buy. One solitary year is very poor! I've also never rated Vent Axia as a particular impressive fabricator. At least one it comes to their extractor fans, they are pretty basic. Link to comment Share on other sites More sharing options...
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