Hello everyone,
I'm a relatively new ecorenovator. Concerning this site it is. I've been working on my house for a number of years now and probably considered a bit of a geek by many people, but it's nice to see I'm not the only one!!
I've read the whole thread from AC-Hacker about building a heat pump, a little in the conservation section and this thread. It took me a few days...
I have a house that's CO2-neutral (including the electric car BMW i3). The house was built in 1987 including a balanced ventilation system with heat recovery (1 cross flow hx). So it should be OK. But the efficiency I measured was approx 65%. This is only based on measured temperatures. So not including moisture effects. So in reality it could be a bit off the real value.
I thought about improving (or replacing) my system to achieve a better efficiency. However I'm also concerned about the AC-fans I have. To my opinion DC fans must be much more efficient, especially because in normal conditions (medium flow) my AC-fans run with a high "slip" (percentage of difference between the rotational speed of the fan and of the rotational speed of the electrical/magnetical field). This is achieved by a series capacitor.
But thinking about my centrifugal fans, I wondered about the fact that in this thread I almost all the times am reading about small axial fans. In my opinion generally the combination of hx, filters, ducting etc. requires a dp that most axial fans don't produce.
Of course I've seen the efficiency calculations (based on temperatures) in this thread and they sometimes looked impressive!
But I wonder if someone really did flow measurements. I fear that in many installations the efficiency might be OK, but the flow is just far below what's required. Normally in Europe we calculate these installations with 30m3/hr per person and some minimum values for toilet and bathroom.
Just curious about the measured flows. Anyone?
If you want to see details about our house and how we achieved CO2-neutrality, take a look at our site. It's in Dutch, but Google translate can help (although sometimes the translations are funny/odd).
The title means: No more energy bill. Here it is:
geen energierekening meer: energieneutraal woonhuis fam. Kriegsman Ootmarsum - Rekening energiebedrijf 2013