Greenway

 

 

  30°C plus Autumn day here a good test fro the cooler in anger   70 Liter bin a tank and a 750LPH bilge pump

 Ventilation Control System Finished  Map to the following dashboard in Hubitat Independent control of 6 fans. Two boost fans individual relays and same 25Khz speed demand 

 Speed Control added to ERV heat exchanger fans and a recirculation/bypass valve between the inlet and exhaust fan. Flower pots hot glue and tie wraps the corner stone of any ventilation system.  Its a throttle valve in a manifold between the inlet and exhaust fan plenums. Fan speed is set using the existing Wemos D1 R2 which can output 25Khz accurately to drive the PWM fan speed demand signal. Code changes to the ERV DAS and the ERV Controller and related Hubitat drivers, now renamed,  Ventilation Controller as it manages the boost fans for the zones. Drivers Some testing with no pipes connected showing the blockage effect of the heat exchanger core Exhaust fan only recirculate open 100%

  As ever on a budget waste not want not approach. mostly stuff I had in stock Code ERV Code Six individually fused channels Power board shown in place. 35 Amp Hall effect current sensor. Driver code here  ERV Code Dashboard for ERV fan control and testing      Six controlled channels with 25Khz PWM fan speed control The first layer of the system. Two Arduinos one for control one for networking, Code here  ERV Code

  Simple loft fan rule

  New dual rotor fans slower and quieter, lower power with better static pressure. Testing shows these to be as good in terms of flow as the faster fans but with more static pressure. I suppose they are designed for use in ducting in a car.  ERV Sensors looking good revised location to get them, deeper into the airflows. All looks good, there is a throttle valve on the bypass now with a single servo. After testing the 4 port valve is not good enough it seems, no surprise. I'm looking at a simple bypass mode with a mixed fresh and conditioned inlet stream.

  Two 40 Watt fans inline 40cm diameter 4mSec at 150mm outlet .Parts total cost NZ$60 

 

 

 

 Matt Resinger on youtube has a lot of videos about the subject. He’s a custom home builder, so he does favor the more expensive materials. But he’s also very focused on making sure things last a long time. I find a lot of his stuff interesting. Here’s one where Matt talks ERV vs HRV Here are a couple This Old House videos on the ERV subject: Seeing it work with smoke bombs A discussion on indoor air quality

I do want to increase the maximum flow rate for the inlet so an additional fan in the inlet filter should help overcome the blockage in the filter its self and heat exchanger core. New filter fan to be placed in the inlet duct. Its in a Sistema box that fits the following filter almost perfectly Features: Double-layer activated carbon filter cloth High filtration efficiency High dust holding capacity Good temperature Resistance Economical, practical and easy to install   There is an additional mesh filter to catch larger debris like leaves  Airflow Sound level

A bit or research and it seems a plenum on the outlet of the heat exchanger seemed worth a try. 60 Litre Plenum on the vent side. Seems to make the vents more balanced measuring the flow I can regulate the rate more evenly with one vent having less effect on the others, I'm going to add a presure sensor to the chamber see if there is any pressure in it I noticed coupling between room vents. e.g. I set one room and move to the next then recheck the first vent and its flow rate was changed. I was never happy with all those Y junctions, a very poor manifold design I suspect. As an added bonus its made the vent even quieter too. It works well within a range I can set the vent flows independently of one another, also the living room and office flows are much improved which have the longest ducts. The flow at the office and living room are 50% higher if needed now which is great for working at home. The office got warm and sticky in the past, not anymore. More Photos Sound test My refere

  Measured Mass Flow in Exhaust Port of ERV  4.4 mS through 15cm duct = 0.0777 m/sec3  so 165m3 is removed in 35 Minutes DAS Reports 0.102 mean with the pitot tube in the exhaust duct 

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