The Rocket Woodstove Forum

Woodstove development using rocketstove technology
 
HomeHome  PortalPortal  GalleryGallery  FAQFAQ  SearchSearch  MemberlistMemberlist  RegisterRegister  Log in  

Share | 
 

 DIY Rocket Cookstove

View previous topic View next topic Go down 
AuthorMessage
greenenergyexperimenter



Posts : 20
Join date : 2013-12-04

PostSubject: DIY Rocket Cookstove   Fri Jan 24, 2014 1:51 pm

I just built a really simple rocket cookstove to help a couple online friends of mine (pretty much the only friends I have lol) to get their feet wet. Here's a video of it in case some of you are interested:



Please note that I had to adjust the feed shelf to look like this:



So far, I've used it to boil a pot of water. It needs a little more tweaking to reduce sooting the bottom of the pan. I also need to time how long it takes to bring it to a boil, so I can determine the BTU output.

Hope you all like this simple stove!
Back to top Go down
gadily
Moderator
Moderator


Posts : 1400
Join date : 2013-12-08

PostSubject: Re: DIY Rocket Cookstove   Sat Jan 25, 2014 12:55 am

heres a few to view and consider





with vortex





gasifier



Back to top Go down
Hitchhiker



Posts : 246
Join date : 2013-12-26
Location : nomad

PostSubject: Re: DIY Rocket Cookstove   Sat Jan 25, 2014 10:52 am

They are fun. Thanks for sharing, green.
Back to top Go down
greenenergyexperimenter



Posts : 20
Join date : 2013-12-04

PostSubject: Re: DIY Rocket Cookstove   Sat Jan 25, 2014 12:59 pm

Thanks for the feedback! I have seen most of those designs. I moved from the cans because I'm tired of my favorite campstoves burning out on me :)I'd have went with a casting like my rocket stove boiler uses, but I don't think it would be durable enough on the go. Hopefully the exhaust elbow will last as long as I hope it will.

I've got some data gathered on this stove. I want to compare it against the claims made by commercial rocket stove manufacturers. Here's a quick and dirty burn video:



By throttling the feed dow a bit, you can avoid soot buildup and increase the heat transfer efficiency by a huge margin. I'd be glad to do a video on that if any of you are interested. Of course, a pot skirt would do magic too.
Back to top Go down
caotropheus
Subscribers
Subscribers


Posts : 333
Join date : 2013-10-07

PostSubject: Re: DIY Rocket Cookstove   Sat Jan 25, 2014 3:06 pm

Nice test. Only by measuring and weighting and counting we can thoroughly control our experiment conditions and improve our designs and stove efficiencies. We have the same small pocket scale, interesting my scale measures in grams  Very Happy 

What is that device you plug the thermocouple to? can you give us more details, what is the temperature range that it measures?

thanks
Back to top Go down
greenenergyexperimenter



Posts : 20
Join date : 2013-12-04

PostSubject: Re: DIY Rocket Cookstove   Sat Jan 25, 2014 3:20 pm

Thanks! Lol on the scale, mine can measure in grams, grains, oz, etc. Handy little device.

The thermocouple is plugged into a digital multimeter and with the right thermocouple, it can read 1500 degrees. The thermocouple I have goes up to 1000.

I did an interesting experiment tonight. The stove drafts most strongly on the topside of the feed tray. I like to consider this the primary air feed. It drafts on the underside, but not as strongly. This gives us a secondary air feed to further clean up the combustion process.

By sticking the probe halfway in the secondary air feed, I measured an air temperature of 160*F. To raise this temperature, I slowed the flow of air and increased the surface area it contacted by using a bit of stainless steel scrubber pad. Not packed solid, just enough to create a "maze" the air would have to pass through. I placed the probe in the center of it so it would not touch any solid stove surface or the scrubber pad.

I then made some interesting observations. First, as expected, the air temperature in the same region increased by a lot. This temperature ranged from as low as 316*F to as high as 589*F. This temperature fluctuated according to the cleanliness of the burn. If I shoved the fuel to the back, the flame became orange and yellow, and the secondary air temperature dropped. If the fuel was pulled back and the exhaust turned to clear, the temperature of the air shot all the way up to 589*.
Back to top Go down
caotropheus
Subscribers
Subscribers


Posts : 333
Join date : 2013-10-07

PostSubject: Re: DIY Rocket Cookstove   Sat Jan 25, 2014 4:18 pm

Again experimentation and measurement is the key. To run our tests we need anemometers to measure air speed and a kit to measure composition of exhaust gases, like Rocket Booster adopted a system used to tune car engines.

Where do you buy those thermocouples? do you get an accurate reading when touching the surface of the steel? Do they have a lifespan? how do you set the multimeter to measure temperature?
Back to top Go down
greenenergyexperimenter



Posts : 20
Join date : 2013-12-04

PostSubject: Re: DIY Rocket Cookstove   Sat Jan 25, 2014 4:50 pm

When shopping for thermocouples, I normally look for the K-type, though this is specific to the meter. This multimeter happened to have that feature, all of my other ones don't.

You can purchase one here: http://www.amazon.com/AGPtek-Channel-Digital-Thermometer-Thermocouple/dp/B0084JQL1Q

This one can display some pretty large temperatures. It can also measure temperature differentials, which comes in real handy when calculating efficiency.

You can get an accurate reading of surface temperatures. It works well in liquids too. I was going for air temperature, which is why I centered it away from surfaces in my test.

They do have a limited lifespan. It is easy to check them by immersing them in ice water or boiling water. Some meters can be calibrated in this fashion.
Back to top Go down
jameshookway

avatar

Posts : 126
Join date : 2013-12-12
Location : Sheffield UK

PostSubject: Re: DIY Rocket Cookstove   Sat Jan 25, 2014 7:29 pm

I bought mine from Ebay it came with two probes. I also bought a third stainless steel probe. The same as this one

http://www.ebay.co.uk/itm/K-Type-Thermocouple-Probe-50-C-to-300-C-for-Digital-Thermometer-UK-seller-/151040923285?pt=UK_BOI_Electrical_Test_Measurement_Equipment_ET&hash=item232abd9695
Back to top Go down
Mr. Heater

avatar

Posts : 116
Join date : 2013-12-09
Location : Northern Illinois

PostSubject: Re: DIY Rocket Cookstove   Sat Jan 25, 2014 8:10 pm

I have worked with Extech dataloggers in the past. Here is a Reed temperature datalogger. Data is stored to a SD card.  Data can be imported into Excel for graphic analysis.

Pricey, but reasonable compared to other data logging systems.

http://www.amazon.com/Reed-SD-947-4-Channel-Thermocouple-Thermometer/dp/B008S0I75E/ref=cm_cr_pr_sims_t



http://www.extech.com/instruments/categories.asp?catid=66
Back to top Go down
Hitchhiker



Posts : 246
Join date : 2013-12-26
Location : nomad

PostSubject: Re: DIY Rocket Cookstove   Sat Jan 25, 2014 9:08 pm

Maybe I missed it, what did you use to cut the paint can? Snips?
Back to top Go down
greenenergyexperimenter



Posts : 20
Join date : 2013-12-04

PostSubject: Re: DIY Rocket Cookstove   Sun Jan 26, 2014 1:17 am

I started the cut with a drilled hole and finished with aviation snips.
Back to top Go down
greenenergyexperimenter



Posts : 20
Join date : 2013-12-04

PostSubject: Re: DIY Rocket Cookstove   Wed Jan 29, 2014 12:03 pm

So here's another litte thing I tried with the stove:



Not a optimal setup, but worked pretty good for being made with bits from my scrap bin.  Very Happy
Back to top Go down
Hitchhiker



Posts : 246
Join date : 2013-12-26
Location : nomad

PostSubject: Re: DIY Rocket Cookstove   Wed Jan 29, 2014 12:27 pm

What type of sealant is at the base of the feed tube?

Would adding warm air to the top of the flame increase the efficiency of combustion?
Back to top Go down
greenenergyexperimenter



Posts : 20
Join date : 2013-12-04

PostSubject: Re: DIY Rocket Cookstove   Wed Jan 29, 2014 12:57 pm

I used a bit of furnace cement around the base of the feed tube and again at the top of the riser to hold the perlite in.

Perlite makes a pretty good insulation. The hottest parts of the outer paint can are around 200*F. If I was smart, I'd have made bigger gaps between the inner L tube and outer paint can to better insulate. Use a little more furnace cement to isolate them. Guess I can still do that.  :shock: 

A secondary air source at the top of the flame just might affect efficiency. I've been experimenting with a simple heat exchanger under the feed shelf to better heat combustion air. My results are not 100% conclusive.

I could always take a couple 3/8" iron pipe nipples and a 90* elbow to build a secondary air injector. Cap off the end that goes into the heat riser and start with a small hole and increase in size or number to find the best amount of air to add. In fact, I think that'll be my next thing to try.
Back to top Go down
Sponsored content




PostSubject: Re: DIY Rocket Cookstove   

Back to top Go down
 
DIY Rocket Cookstove
View previous topic View next topic Back to top 
Page 1 of 1
 Similar topics
-
» New rocket Stove
» Turbo Rocket stove
» My first rocket stove space heater
» Fan Use With Rocket Stoves
» My friend had a dream with rocket exploding

Permissions in this forum:You cannot reply to topics in this forum
The Rocket Woodstove Forum :: Main :: Rocketstoves (ideas and research members only) :: Show us your stove-
Jump to: