topbanner.gif
September 26 2017 14:37:09
Login
Username

Password



Not a member yet?
Click here to register.

Forgotten your password?
Request a new one here.
Navigation
bullet2.gif HOMEROASTERS.ORG
bullet2.gif Active Forums
bullet2.gif FORUM INDEX
bullet2.gif Downloads
bullet2.gif News
bullet2.gif Forum FAQ
bullet2.gif Contact Me
bullet2.gif Photo Gallery
bullet2.gif Search
bullet2.gif User's Voice
Forum Threads
Newest Threads
bullet2.gif flatpicker and home ...
bullet2.gif 1kg drum roaster build
bullet2.gif The Kaldi Home Roaster
bullet2.gif Bread Maker - 1.5 lb
bullet2.gif Vacuum appropriate f...
Hottest Threads
bullet2.gif Building a drum r... [146]
bullet2.gif Bobby M15's drum [76]
bullet2.gif Baby George Forem... [53]
bullet2.gif 500g (hopefully) ... [34]
bullet2.gif Big Price Drop on... [29]
Donate to HRO
Please enter your site username (if you have one) and your email address (required) to be sent with this donation for tracking and contact purposes.


Site Username
If you don't have a site username, just enter "Guest"


eMail Address **REQUIRED**

Users Online
bullet2.gif Guests Online: 1

bullet2.gif Members Online: 0

bullet2.gif Total Members: 5,037
bullet2.gif Newest Member: Vutran
BotSlap Panel
bullet2.gif Last check: 09/26/2017 14:23
bullet2.gif Slap count: 0
bullet2.gif Last checked ID: 6147
View Thread
Who is here? 1 guest(s)
 Print Thread
HOW MUCH ENERGY DO YOU USE?
oldgearhead
The calculation used for loads fitting a Mason jar (430-440 grams) has proven very good: (95-garage ambient in C = % on time of the heater). Because I use % on time instead of PID temperature control the energy used per batch is very easy to calculate power converted to energy used:
2/24/2017 - Temperature in the garage was 70F (95-21C = 74%), 1147 watts x 3.412 = 3916 BTU/hr.
Divide by 5 to see how much was used in 12 minutes = 783 BTUs/batch.
3/01/2017 It was 20F colder today (95-13C = 82%) on time or 1271 Watts equals 1271 x 3.414 = 4339 BTU/hr x 20% = 868 BTU/batch.

These, energy used, calculations are over two times the theoretical number of 350 btus/pound set forth by Michael Sivetz in his first book "Coffee Processing Technology". We know from further reading that recycling 204C commercial fluid-bed roasters did not get much better than 1200 btus/pound.

First crack was a very repeatable nine minutes and thirty seconds and my delta T appears variable from 134F to 229F and the final temperature was 412F at 11.5 minutes. I am sure the delta T is not that variable because the cool beans influence the reading on the temperature probe mounted only 1.5 inches below them. However, the temperature rate-of-rise is rather dependent on the blower speed adjustment, but it is ever increasing during each roast.

My roaster mixes ambient air directly with the hot air exiting the top of the roast chamber and introduces it to the blower inlet. Inlet temperatures range from 150F to 180F. The spa-used, two-stage, flow-through, vac blower has been used twice a week for more than five years.
oldgearhead attached the following image:
dsc_0095_9.jpg

No oil on my beans...
 
coffeeroastersclub
OGH, here is something I always wanted to ask you. What percentage do you think is recycled air? Do you have the ambient air inlet located at the bottom of the mix box and the final outlet on the very top? This is where I get confused due to negative (?) air pressure at the final exit? Positive air pressure at the ambient inlet?

Len
"If this is coffee, please bring me some tea but if this is tea, please bring me some coffee." ~Abraham Lincoln
 
http://www.coffeeroastersclub.com
oldgearhead
The volume of air being pulled down through the inlet pipe is 16.5-17.5 SCFM and it's temperature is 150-180F. At a standard ambient air temperature of 68F that is about 100F increase, or about 25%...The pipe marked with the red tape is the inlet air supply. Ambient air is available under no positive or negative pressure..I need to update my photos, the chaff collector was removed years ago..
oldgearhead attached the following image:
dsc_8386_10.jpg

Edited by oldgearhead on 03/15/2017 12:17
No oil on my beans...
 
coffeeroastersclub
Is there exhaust air also in that area? I guess I am not visualizing the air circulation pattern.

Len
"If this is coffee, please bring me some tea but if this is tea, please bring me some coffee." ~Abraham Lincoln
 
http://www.coffeeroastersclub.com
oldgearhead
Please you look at the image I posted above, you will notice the top of the unit hinges down, covering both the inlet and RC outlet pipes. The 'box' is open at the back, unless it is below freezing, then it is baffled. Any positive pressure inside the 'box' is exited out through the small, former. water door. If you are familiar with commercial pour-over brewers you will get the picture.
The temperature drop across the roast chamber is controlled by insulating it during 30-50F garage temperatures..It will not be fun today, roasting in 40F ambient with an un-insulated roast chamber. However, I will post the energy used BTUs/batch later. I will also record the temperature drop across the roast chamber. It is 17F this morning so I'll wait till afternoon...

No oil on my beans...
 
coffeeroastersclub
I think I get it now. So any positive exhaust pressure in that upper boxed chamber would cause the exhaust to exit the slitted vents in the upper box?

Len
"If this is coffee, please bring me some tea but if this is tea, please bring me some coffee." ~Abraham Lincoln
 
http://www.coffeeroastersclub.com
oldgearhead
No, not the slotted vents, they are sealed with insulation. The 'water' door used to add add water when it was a brewer. Located on top of the 'box'..
oldgearhead attached the following image:
dsc_9153-2.jpg

No oil on my beans...
 
oldgearhead
3/16/2017- The garage temperature was a cool 8C (46F) and this was not good for the temperature drop across the un-insulated glass roast chamber with an average drop of 87F. I like to keep it below 60F. The % output setting was 95-8 = 87% or 1550 x .87 = 1384 watts.
Load was 454 grams of Rwanda Kiru Lake from Happy Bean.
Energy used = (1348 x 3.414)/5 = 920 btus/pound.
The shrinkage was 454-388 = 66 grams or 14%.
I would call the resulting roasted beans a City roast. I prefer City+. But the cracks around 10 minutes were very hard to hear, so I ended the roast at exactly 12 minutes and 407F.

No oil on my beans...
 
Jump to Forum:
Similar Threads
Thread Forum Replies Last Post
Big energy coffee@ 7~11 Member Photo's, Blogs, Websites and Pod Casts 4 05/30/2012 19:56
Coffee losing market-share to energy drinks? Books, Magazines, Blogs and Articles 7 11/17/2010 02:56
Energy to raise coffee bean temp? Roasting Coffee 12 07/22/2010 09:16
Member Poll
What is your usual batch size for roasting?

6oz

8oz

9 to 10oz

1lb to 1.5lb

2 to 3 pounds

over 3 pounds

You must login to vote.
Shoutbox
You must login to post a message.

JackH
09/26/2017 06:06
Welcome Vutran

JackH
09/26/2017 06:05
welcome2 ayuh22

JackH
09/25/2017 07:41
Welcome John Grossi

JackH
09/25/2017 07:40
welcome2 AEtherus

allenb
09/23/2017 07:49
mraphael Welcome

JackH
09/22/2017 13:26
Welcome Shangri-Brah

JackH
09/22/2017 13:23
welcome2 farmer coffee

JackH
09/21/2017 02:24
Welcome jawjatek

allenb
09/19/2017 17:50
sandbf Welcome

JackH
09/17/2017 12:59
welcome2 tultulini

JackH
09/16/2017 13:10
Welcome russ

allenb
09/16/2017 11:27
nickso Welcome

allenb
09/16/2017 11:25
daustin Welcome

allenb
09/16/2017 06:46
kerfboy welcome to forum

JackH
09/15/2017 02:31
welcome2 coffeeismagick