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06-10-13, 09:26 AM | #1 |
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home made recuperator
Hello to all! Im a new guy here on forum reading great posts here and hoping later i can contribute some experience and knowledge...
Since recuperators or heat recovery ventilation units are very expensive plus none has all the features I want, I decided to build one on my own. Electronics will be done with arduino and additional sensors, if you are interested I will describe it in detail later. Heat exchanger will be aluminum counter flow,purchased for about 200$. Housing is also not a problem. I stucked with buying some affordable centrifugal EC fans. Fans should be EC type, with ball bearings and controllable rpm. As my house has 200 m2 my target flow is 300 m3/h max. Can you recommend some fans with goog price? I know some ebm which are used by SUN are good priced on ebay, but I am looking for centrifgal type, not axial. Any hint or info appreciated. Best regards from Slovenia! Damo |
06-10-13, 10:34 AM | #2 |
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Welcome to the site Damo!
I take it you've read this thread: http://ecorenovator.org/forum/conser...exchanger.html Its really long but contains tons of info including talk on fan selection.
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06-11-13, 06:13 AM | #3 |
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Hello Daox,
Yes, I've read it and still don't have an idea which fans to use, besides EBM. Somehave I have second thought on using axial type. Now I try to read long long thread from that Polish forum. Google translate is my friend. |
06-11-13, 04:21 PM | #4 | |
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Heat Recovery Ventilator
Quote:
I'm very interested in your fan controller and your whole heat recovery project. Please let us know how your project is proceeding. I am working on a similar project, also using an Arduino to control the fan, and the controller part of that project can be found HERE. Used high efficiency centrifugal fans can be found on ebay HERE. I was able to find very good EC fans at a very good price on ebay, you just have to keep coming back and looking. Good luck on your project. Sincerely, -AC_Hacker
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06-12-13, 01:26 AM | #5 |
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Hello,
I will keep posting here as the project will advance. For now here is initial schematics. CPU: Arduino Due Communication: Arduino Ethernet Shield, RS485 module Temp & Humidity sensors: DHT22 CO2 sensor: T6004 air flow sensor: MD0550 delta P: I2C sensor range 50 mbar Comments welcome. Last edited by damo; 06-12-13 at 02:05 AM.. |
The Following User Says Thank You to damo For This Useful Post: | Piwoslaw (06-29-13) |
06-12-13, 10:14 AM | #6 | |
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Quote:
Wow! You are making a very smart controller here! I have not worked with the DHT22, I did try the DHT11 and was not pleased with the accuracy. I next tried the SHT15 humidity and temperature sensor from Sensirion and now I am so confidant in its accuracy, that it has become the standard by which I compare all my other temperature and humidity measuring instruments. Also, regarding the T6004, I used the analog output from the T6004 to my Teensy(Arduino clone). It works very well, but from time to time I get readings that are extremely wrong, and require me to do a reset. On my thread, you will find a link to a document that explains the serial protocol for the T6004. It was a bit too complex for me, but if you can figure it out, I would like to use that approach, too. I am interested to know how your air flow sensor works for you. I decided that I was more interested in how the fresh air flow affected the CO2 levels and humidity levels than what the air flow was. Maybe your idea is better. Your idea to measure delta P is a very good one. How will you measure this? I ordered a pair of barometric sensors, one for indoor air pressure, one for outdoor air pressure, that should be able to resolve whether a door or window is open. This could be used to turn off the fans on the controller. It might also be possible to do this by monitoring the current draw of the fans. I like the idea of adding Ethernet to the device, but I'm not sure how useful it would actually be. I had thought of this, but I decided that I wanted my controller to simply do its job, it did not need to tell the world what it was doing. I admit that, in the past, I have been lacking in vision. Good luck with your project, take lots of photographs, that really helps other people understand what you are doing. Sincerely, AC_Hacker
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06-14-13, 03:52 AM | #7 |
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Hello,
DHT22 are more accurate than DHT11 and a lot cheaper than Sensirion SHT. As I read they are stable, so some offset error is easily corrected by software. Thanks for info about T6004, I will include power control so in case of erratic reading I can reset it. I also saw some cheat CO2 sensor, but I can't remember where. As of dP sensor I plan to use I2C sensor from HYB. My wife sells them so I guess it shouldn't be a problem to get one free sample . I use hydronic floor heating, but also have a fireplace installed in the living room. I use it from time to time to get that good warm feeling in the winter. To prevent smoking the house and possible CO build up, I need a small positive pressure in the house. I plan to control suction fan speed and inake fan will follow by just balancing the pressure differential. At least that is in theory. I haven't try flow sensor yet. I want to measure flow 0-100%, not in real values. Maybe these sensor will have no use, but I will plan them in the mainboard anyway. Ventilation will be based on timer and house air humidiy. Since in the house live only 4 people, humidity build up is more problem than CO2. So CO2 meter will be there just for show-off Ethernet will be used for reporting data to COSM (now Xively). Also future plan is to build a graphical web page with all current data/settings. RS485 is for remote wired LCD and keypad. For now I am still in selecting hardware components. best regards, Damo |
06-14-13, 01:38 PM | #8 | |
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This does sound interesting. I have tried to guess what sensor you are describing. Would THIS be the one you have in mind?
I was considering something like this to be able to measure how leaky my house is. Quote:
This sounds like a very interesting project! I am interested to see how it develops. Best, -AC_Hacker
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06-19-13, 02:32 AM | #9 |
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Hello again,
in mean time I ordered some parts for controller: Arduino Mega and temp. & humidity sensors DHT22. Still looking where to get a good deal on CO2 sensors, store from ACHacker's link don't offer them anymore. Absolutely I will take humidity and also CO2 sensor into ventilation strategy. I also got a good deal on a EBM fans DV6424 - got 2 pcs for $45, shipping included. I excpect them to drive on low power (low voltage + low PWM) I assume they won't be too loud. Next is ordering a heat exchanger, which will be counterflow aluminium type Klingenburg GS35-300. Price is about $200 + shipping, which seems to be a good deal too. Also I am looking how to solve a bypass hatch. Pressure sensors - I don't know exact model number yet, I guess 50mbar will be sufficient range. I prefer digital (I2C), but analog will also do. Another idea came into my mind - how to harvest heat energy from fireplace's chimney? Chimney is an insulated stainless steel, but in upper story I have made a chamber about 40x40cm x 2.5m, and inside is uninsulated chimney. Originally I planned to ventilate this chamber and thus heat up a staircase, but it turned out that this is not necessary. Anyway this chamber is now sealed and I wonder how to transfer heat to ventilation system without mixing air. Thinking of some kind of heat pipe, but have no idea if I could transfer some serious power (1-2 kW). Last edited by damo; 06-20-13 at 03:28 AM.. |
06-22-13, 01:53 PM | #10 | |
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Quote:
Also, keep in mind that you will have condensation that you will need to deal with... I had a problem with PWM modulation sound. I couldn't hear it, but it was driving my girlfriend crazy. If you are a truly awesome programmer, you will be able to raise the PWM frequency to a point higher than human hearing. (and tell me how you did it) Either that or get a girlfriend with bad hearing. Best, -AC
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I'm not an HVAC technician. In fact, I'm barely even a hacker... Last edited by AC_Hacker; 06-22-13 at 02:00 PM.. |
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