ARC E-Newsletter 2/21/25: Wow! Tom Reed Forced Draft TLUDS Are Great!
Aprovecho Research Center
Wow! Tom Reed Forced Draft TLUDs Are Great!
The Tom Reed Alpha Limited Forced Draft TLUD stoves (India)
These six-inch and four-inch in diameter FD-TLUD stoves are powered by two AA batteries and are well known to be inexpensive and clean burning. The smaller stove was the “high combustion efficiency” stove used in a 2015 Round Robin test series at Regional Testing and Knowledge Centers. As shown, the Tom Reed stove uses two crossed pieces of metal as pot supports.
The four inch in diameter ARC Round Robin test results were:
As a part of a recent Osprey stove improvement project, ARC added a stainless steel Winiarski stovetop to the smaller and larger Alpha Limited stoves that increased thermal efficiency and resulted in reductions of PM2.5 in the larger stove. The added stovetop seemed to encourage the injected, horizontal secondary air jets to more powerfully cover the top of the fuel?
Winiarski stove top
With the addition of the SSM Winiarski stovetop, (6mm pot supports and flat perimeter to accommodate a pot skirt) the larger Alpha Limited stove became a very clean burning TLUD. The ISO PM2.5 Tier 4 is less than 62 mg/MJd. The Tier 5 (an inspirational goal for PM2.5) is less than 5 mg/MJd. In a single test, the improved larger Alpha stove achieved 6mg/MJd for PM2.5 after burning for 94 minutes at 4.6 kW.
- Thermal efficiency_w_char 58%
- firepower_w_char_high power 4.6 kW
- CO_useful_energy_delivered_ 1 g/MJd
- PM_useful_energy_delivered 6 mg/MJd
- PM mass time 1 mg/min
- time_to_boil_high power 9.4 min (5 liters in SSM SuperPot)
- ISO TIERS
- Tier_efficiency_w_char Tier 5
- Tier_CO_useful_energy_delivered Tier 5
- Tier_PM_useful_energy_delivered Tier 4
The thermal efficiency in the smaller diameter Alpha Limited stove was improved but the PM2.5 was not reduced when adding the Winiarski stovetop. The smaller stove ran for 26 minutes on 0.4 kg of Douglas fir pellets.
- Thermal efficiency_w_char_ 56%
- firepower_w_char_high power 2.6 kW
- CO_useful_energy_delivered_ 1 g/MJd
- PM_useful_energy_delivered 30 mg/MJd
- PM mass time 3 mg/min
- time_to_boil_high power 25.6 min (5 liters in SSM SuperPot)
- ISO TIERS
- Tier_efficiency_w_char Tier 5
- Tier_CO_useful_energy_delivered Tier 5
- Tier_PM_useful_energy_delivered Tier 4
The following list describes the features in the larger Tom Reed Alpha Limited FD-TLUD. Perhaps, adapting these hole sizes and air pressure, etc. to other stoves might result in reductions of emissions while increasing thermal efficiency?
- Diameter of 13 Primary Air Holes (mm) 2.5
- # Secondary Air Holes 36
- Diameter Secondary Air Holes (mm) 4/7
- Chamber Diameter (mm) 155
- Chamber Area (mm^2) 487
- Distance between Secondary Air Holes (mm) 13.52
- Secondary Air Pressure (in H2O) 0.095
- Secondary Air Pressure w/ Blocked Primary Air holes (in H2O) 0.11
- SSM Stovetop Hole Diameter (mm) 105
- SSM Stovetop Hole Diameter / Cross Sectional Area 0.677
Give it a try?
Tell us what happens?
*Read more about Dr. Tom Reed and his work in our Newsletter Archive.*
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