Greenway

I think I'll build one of these https://woodgears.ca/dust_collector/impeller.html Credit  https://woodgears.ca/ I need to cost this out properly I suspect the valves will push the cost up to high might bi simpler to build a fan What about this This might be better and more compact The valves I want a booster exhaust air mover that can say exchange all the air in the house in 15 or 20 minutes The calculation above shows I can do this with one or two 75cm gym ball lungs. So the idea is make a rolling diagram or ball compressor from 2 NZ$12 gym balls and a windscreen wiper motor. So 45 decrees of travel in 2.5 seconds? A wiper motor can do that but the Torque needed at a radius of say 50cm would be?????? Hard to say these is virtually no air pressure however the ball has significant wall thickness best discovered by experimentation,. I think. Torque needed to excerpt 2kg of thrust at 50cm is approximately 9.81 Nm unsurprisingly, or 1kg/Meter. Can a wiper motor deliver 1kg at a half me

4 port fan working

  After a few experiments I decided I wanted the following options for the input air source. 1) Fresh air from roof top. Function as a vanilla balanced ERV ventilation system, all exhaust air passes through the heat exchanger, all incoming air is warmed by the heat exchanger. 2) Loft air, typically warmer if the Sun is out even on a cold day. Reduce need for heating during the day. 3) Fresh Air bypassing the heat exchanger to reduce the need fore running the heat pump on sunny days when the air temperature is still quite low. 4) Block all four ports to prevent air moving from convection or an open window raising or reducing air pressure in the room. So the four port valve was born. ts got a dual drive now which works really well. The wooden gear was inspired by the Marble Machine i have toughened the teeth with Epoxy now which make it quite substantial.

 Looking at the specifications of propitiatory systems it seems that the fans are nothing special. They typically use Axial flow fans with AC voltage motors around 60 Watts seems suitable for our house. In order to allow me to do this without an electrical certificate my system is entirely 12 volt.  The fans I have are pretty quiet to so it seems like win win to me less that US$30 each for the 60 W devices and US$16 for the boost fans. Computer fans are a good low cost option. Quiet long lived and they have built in speed controllers too. I am using two fan types in the system. I bought them cheapef than this Specifications : -- Size: approx. 120*120*38 mm -- Voltage: 12(V) -- Blast Capacity: 280.38CFM -- Current: 5.0A -- Rotate Speed: 7500CPM(r/min) -- Noise Level: 64DBA -- Wind Pressure: 24.60 mmH2O -- Bearing: High precision double ball bearing -- Operating Temperature: -10℃ ~ + 70℃ -- Storage Temperature: -40℃~+70℃ -- Power range: Plus or minus 15% of rated power supply -- Insulati