SteamyTea Posted October 13, 2021 Share Posted October 13, 2021 12 minutes ago, ProDave said: 50Pa is only 5mm H2O on a manometer. Hard to read with any accuracy but you will get an idea. An inclined manometer may be more accurate. Pick another fluid. https://www.engineeringtoolbox.com/fuels-densities-specific-volumes-d_166.html Link to comment Share on other sites More sharing options...
dpmiller Posted October 13, 2021 Share Posted October 13, 2021 IIRC manometer fluid for the sensitive inclined filter loss gauges is basically white spirit with dye in. Link to comment Share on other sites More sharing options...
Jenki Posted October 15, 2021 Share Posted October 15, 2021 On 13/10/2021 at 08:05, SteamyTea said: Have you used a manometer? Then worked out the pressures. Anyone know what calculations are needed? I understand you seal up and put the fan on and regulate the fan speed to get a differential pressure of 50Pa. What I don't understand is how you work out the air change. Is that related to the speed of the fan and the extraction rate of the blades? Or is it using an aneometer and cone similar to balancing MHRV? I can see the benefits of rigging up a DIY test after the airtight membrane is installed. It would be better if I could get some figures as well.? Link to comment Share on other sites More sharing options...
ProDave Posted October 15, 2021 Author Share Posted October 15, 2021 What I did is used an anemometer to measure the speed of airflow flowing past the fan to achieve equilibrium at 50Pa. then knowing the area of the fan you calculate the volume of air flowing past the fan in a given time and that Vs the volume of the house gives you ACH. Just a case of scaling to get airflow units and volume of house units the same. So if you want ACH calculate the volume of air flowing past the fan in an hour, and compare that to the total building volume. 1 Link to comment Share on other sites More sharing options...
SteamyTea Posted October 15, 2021 Share Posted October 15, 2021 1 hour ago, ProDave said: What I did is used an anemometer to measure the speed of airflow flowing past the fan to achieve equilibrium at 50Pa. then knowing the area of the fan you calculate the volume of air flowing past the fan in a given time and that Vs the volume of the house gives you ACH. Just a case of scaling to get airflow units and volume of house units the same. So if you want ACH calculate the volume of air flowing past the fan in an hour, and compare that to the total building volume. What I would do. Just take several readings across the diameter of the fan and take the average airflow. Link to comment Share on other sites More sharing options...
dpmiller Posted October 15, 2021 Share Posted October 15, 2021 the flow would be too turbulent for the average anaemometer to deal with IMO Link to comment Share on other sites More sharing options...
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