Navitron Renewable Energy and Sustainability Forum

WIND TURBINES => Direct Heating Systems => Topic started by: billi on October 28, 2018, 03:25:38 PM



Title: solar air heater flow rate
Post by: billi on October 28, 2018, 03:25:38 PM
Hi there

Am having a fan running to push warm air from a conservatory    as a temporarry  setup , but cannot find the airflow  specs for that model , its about 8" propeller diam and says about  20 watt ...., does the tric  ... and heats the whole house today  at temps outside about 5  degrees

Would like to take one glass panel out of the window and fit  a fan idea with a termostat , found these  and they would fit  (2 of them )  if they deliver what is described it sounds the job 200 m3 per hour then ..... what do you think  ,  would the airflow of the temporarry one be much higher ?
https://www.technikcoach.de/en/silent-belueftungseinheit-fuer-ut-rack-und-rfa?fbclid=IwAR1V7VIlO_c4Jk85857LqDgvDADXA5uJ5tuXSjeeM4ECP9YEErjGSMlQDmE

fan details here

https://www.blacknoise.com/site/en/products/noiseblocker-it-fans/nb-blacksilentfan-series/120x120x25mm.php


Title: Re: solar air heater flow rate
Post by: rogeriko on October 28, 2018, 04:49:49 PM
Those are just computer fans. Go to any computer repair shop and they will give you a bunch for free, then you can try them. They will not move as much air as the big one.


Title: Re: solar air heater flow rate
Post by: knighty on October 28, 2018, 07:00:36 PM
just check how many watts the motors are... for a fan watts = air moved

you big one is 18watts, those little ones are 1.8watts

what size do you need?


Title: Re: solar air heater flow rate
Post by: billi on October 28, 2018, 07:16:36 PM
..... not as easy  i am afraid ,  some  bathroom vents have lot more watt but much lesser air flow than some computer fans , but i think they have to  move air through longer pipes .... so might  need more pressure to overcome

Hmm ...... but if i have a look at the  established air collectors  than the big one of those with 6m2  collector area has about 250 m3 airflow ..... but i guess here as well  air has to be pushed through pipe lenght

 so i guess i  try to find something  with at least 200 m3  as  the greenhouse  should create   more heat  with about  25 m2 glass roof and wall




Title: Re: solar air heater flow rate
Post by: skyewright on October 29, 2018, 10:31:28 AM
Any chance of allowing (controllable) high & low (height)  vents between the house & conservatory, then just letting convection do it's thing to transfer & mix the air?


Title: Re: solar air heater flow rate
Post by: MeatyFool on October 29, 2018, 01:32:40 PM
This!

https://en.wikipedia.org/wiki/Trombe_wall

Meatyfool..


Title: Re: solar air heater flow rate
Post by: billi on October 29, 2018, 01:55:00 PM
A Fan is  needed to push the warm air fast into the rooms , without the fan and the window to the room open , the greenhouse heats up a lot  and cause the fan is  having a thermostat it will decide itself when to start and stop , so one has not to worry too much of heatloss  back into the greenhouse , cause window is closed then and the fan inbuilt into the window  gets a flap



Title: Re: solar air heater flow rate
Post by: skyewright on October 29, 2018, 02:06:10 PM
A Fan is  needed to push the warm air fast into the rooms , without the fan and the window to the room open , the greenhouse heats up a lot  and cause the fan is  having a thermostat it will decide itself when to start and stop , so one has not to worry too much of heatloss  back into the greenhouse , cause window is closed then and the fan inbuilt into the window  gets a flap

Even with a fan (at high level), a low level return flap to let colder house air into the greenhouse would help improve circulation (& make life easier for the fan, so it could work more efficiently?).

Edit to add:

PS. I just noticed that it was 24-25C in our conservatory, so I've opened the door & windows between here & there, and internal doors. I'll close when it gets down to 21-22C. For us at least 2-3 degrees difference seems adequate to encourage pretty effective heat distribution into the house. I can see the temps from my computer if I wish, but once you've been doing it for a few years you can get a reasonable idea from just being 'aware'. One of the joys of working from home...  :)