This page is an automatic translation to Chinese of CCAT rocket stove.This translation is distributed in the hope that it will be useful, but without any guarantee of accuracy.Read more...

这种改进的燃料炉或火箭炉是加州理工洪堡分校Engr305的最后一个项目。该项目的目标是为加州理工洪堡校区的校园适当技术中心建造一个示范火箭炉。火箭炉将成为改进燃料炉技术和开发的范例;参观该中心的学生和公众将了解世界各地改进燃料炉的设计、功能和需求。

火箭炉还将使该中心的居民能够使用传统的生物质做饭，减少他们对石油能源的依赖。重要的是要注意，火箭炉是为世界各地依赖生物质作为烹饪燃料的人口设计的。在发达国家使用火箭炉是没有必要的。使用现代烹饪方法的发达国家不会面临与传统烹饪方法相关的健康和环境问题。改进的燃料炉由Daniel Moyer和Tyler Jones设计，制造和测试。

人们越来越依赖生物质作为烹饪燃料，从而阻碍了现代烹饪方法的下一步。发展中国家的人们想要与美国郊区相同的现代、自清洁、对流、下吸式炉。许多人认为现代烹饪方法更合适。现代烹饪方法在燃料转化方面是有效的，并且产生的大气颗粒较少，但是对石油的依赖阻碍了现代烹饪方法的适用性。

改进的炉灶是解决三座岩石火灾对环境和社会的负面影响的尝试。改进的炉灶可提高燃料消耗效率并减少释放到室内烹饪环境中的污染。改进的燃料炉设计采用金属外壳和绝缘材料围堵火。改进的燃料炉改善了传热和燃料燃烧，从而产生了高效清洁燃烧的木炉。

设计

设计原则

1. 一个结构良好的火箭炉将允许空气流通。考虑到这一点，为空气提供均匀的通道非常重要。烟囱、燃烧室和裙部间隙都应具有相同的横截面积。
2. 除非氧气循环，否则火会窒息。在建造燃烧室时，有必要为燃料提供一个架子。这样，新鲜空气将被拉到燃烧的燃料下面。
3. 烟囱应该很短，刚好到达锅上方。这允许热气体更快地流过系统。
4. 热量将从燃烧室辐射出来。为了提高效率，请在腔室周围进行绝缘。

材料

用于建造火箭炉主体的材料由回收的金属桶制成。一个旧的柠檬油罐被修剪成适当的尺寸，成为我们的锅裙。隔热燃烧室由在当地陶器用品店购买的陶瓷隔热砖组成。腔室由 3 号不锈钢金属镀层固定在一起，并用 8/<> 英寸硬件固定。用于建造火箭炉的硬件包括机器螺钉、螺母、垫圈和钣金螺钉;我们使用的所有硬件都是从当地的五金店购买的。

物料清单

施工步骤

1

方形燃烧室由绝缘砖砌成。砖块是用锯切割和成型的。使用耐热腻子作为密封剂。

2

Fig 2.1: Metal Bracket

A metal bracket supports a sheet metal case that holds the combustion chamber in place. The metal was cut out with tin snips and fastened with screws at the edges.

3

Fig 1.2: Combustion chamber inside the barrel

Drill and tin snips are used to cut a square out of the barrel corresponding to the dimensions of the metal casing. The casing for the combustion chamber fits into the hole, protruding on both sides.

4

Fig 1.1: Metal Case

The casing is firmly secured to a metal beam that stretches across the barrel. This beam is secured on both sides with L brackets.

5

Fig 2.2: Barrel filled with Vermiculite

Vermiculite is poured into the barrel in order to insulate the combustion chamber. This insulation fills the space between the chamber and the barrel and is filled as high as the top of the chamber.

6

Fig 3: Sheet metal shelf

At the top opening of the combustion chamber we constructed a metal shelf. This shelf is circular and perfectly fits inside of the barrel. It has a square cut in it corresponding to the top opening of the combustion chamber. This allows for gasses to pass through, but seals them off from the bottom half of the barrel. The shelf is secured firmly to the outside of the barrel with L brackets and screws.

7

Fig 4.1: Skirt

In the top half of the barrel, we constructed a skirt. This skirt surrounds the cooking pot, leaving a small gap on the bottom and the sides. The skirt was constructed out of a can. We used tin snips to cut a square opening in the bottom to channel the hot gasses. The top of the can was cut completely open with a Sawzall. The skirt is fastened to the shelf with screws and washers.

8

Fig 4.2: Skirt inside barrel

The pot is inserted into an opening in the top of the barrel. Here we have cut out a circle with tin snips and then carefully bent the metal down at a right angle using square pliers and a mallet. This way the pot is extra sealed and the opening for it is not jagged or sharp.

9

Fig 5.1: Lid

Fig 5.2: Complete Rocket Stove

We cut a hole out of the upper side of the barrel and fastened a circular metal chimney over the hole using screws.

10

Fig 6: Stainless steel pot

To use our rocket stove, burn fuel inside the combustion chamber and set the pot inside the skirt.

Testing

Testing is essential to rocket stove projects. Testing should happen throughout the entire life of a stove project. The evaluation of improved stoves helps determine if the model is marketable, whether production costs are as low as possible, and if improvements are needed. "Careful testing of stoves has resulted in a more accurate understanding of how to make a better stove. Without experimentation and testing, the development of a stove is based on conjecture". Technical advances in energy efficiency alone will not ensure success. Stove programs must be complemented by appropriate project design, implementation and proper institutional support. Without proper testing, stove programs will have unrealistic expectation of the efficiency of improved stoves. Stove programs can overestimate the efficiency of improved stoves when tested in a controlled lab setting. Improved stoves never do as well in real households. "The fuel savings that can be attained in a laboratory often have little relationship to savings possible under field conditions"^[1]. Many stove programs in controlled lab settings achieved a 75% reduction in fuel consumption. After examination of early stove programs, fuel efficiency expectations of improved stoves have been substantially reduced. "Most people in the stove community now agree that a 50% decrease in fuel consumption should be considered a major achievement and that should be content with a savings of 25% or even less".^[1] Laboratory settings can be valuable with designing and initial testing of improved stoves; testing in field conditions can ensure the final product is built and designed correctly. Producing a stove design that adheres and conforms to local culture is vital in ensuring a successful stove program.

Types of testing

In testing our stove, we wanted to find out how long it would take to boil water and how much wood was being used. We also inspected the ashes to determine if the wood was fully combusted. Ultimately we did three types of tests.

1. We boiled water from a cold start and from hot start. Hot start means that we started the test when there was already wood burning. The starting temperature for the water was sixty three degrees.
2. We maintained a boil for 30 minutes. We did not start the clock until all of the wood that initially brought the water to a boil had burned out. This gave us more accurate results.

Results

1. It took 13 minutes and.36 pounds of wood to heat four liters of water 108 ^oF. This was done from a cold start (nothing burning initially). The starting temperature was 62^oF and the final temperature was 170^oF.
2. From a hot start, it took 10 minutes and.56 pounds of wood to heat the same volume of water 149 ^oF. The starting temperature was 63 ^oF and the final temperature was 212 ^oF.
3. From a hot start, it took 11 minutes and.72 pounds of wood to heat six liters of water 146 ^oF. The starting temperature was 64 ^oF and the final temperature was 210 ^oF.
4. To keep six liters of water boiling for half of an hour it took.18 pounds of wood. The starting temperature was 212 ^oF and the final temperature was 210 ^oF.

Conclusion

The results of our testing demonstrated that the project was a success. The first thing that we noticed was that the air circulation is excellent. We never had a problem getting enough air into the fire or with having smoke back out of the combustion chamber. This makes starting a fire very easy. Also, we were happy to see that there were hardly any ashes left over. The wood burned hot and combusted completely. Although the top of the stove gets hot when the fire is burning fast, the vermiculite does a very good job of insulating the bottom part. The lower half of the stove never got too hot to touch and the very base never even got warm. Once a fire is going, it must be tended regularly. As well as adding new wood as the fire burns, it is important to constantly push burning pieces all the way into the chamber. Our stove is very efficient. To cook spaghetti in our stove would require roughly one pound of wood and would take only a few minutes longer than a regular stove. By using a lot of wood and creating a big flame, it is possible to boil water quickly. With less wood, the same amount of water can be boiled but it takes longer. It takes a lot of wood to heat water initially, but to keep it boiling requires very little wood. One pound of wood would keep six liters of water boiling for about two and a half hours. When our stove is burning, the pot and the skirt get a lot of soot. Periodically, it will be necessary to clean this soot out.

In building a rocket stove, we learned some important things. First, it would be possible to construct this type of stove using only recycled materials. The hardware would be the most difficult to find. It would also be possible to construct our rocket stove with out the use of power tools. We could have used a hammer and spike instead of a drill. We also could have used a hacksaw instead of a Sawzall. We only used this tool once, to cut the skirt out. As we anticipated, the top of the stove got hot. If our stove was placed inside of another barrel and insulated, it would be more user-friendly. Personally, I would rather deal with the hot surface than to put more work into the stove. In a situation where there were children using the stove, the hot metal could be dangerous. The one thing that our stove lacks is a shelf for extra long pieces of wood to rest on while they are combusting.

Populations around the world are going to continue to use biomass fuel for the indefinite future. The use of improved stoves can help control the external costs to both the environment and human society. "It seems inevitable that an increasing amount of biomass fuel will be bought and burned in purchased stoves".^[1] Fuel savings may not be the driving factor in the adaptation of improved stoves. Improved stoves work because they make cooking quicker, safer, and cleaner. Improved stoves protect children from the dangers of burns from the open fire, reduce respiratory diseases, and burn clean and free of soot.

September 2011 update

Logan Ward and Erik Rasmussen

On September 11, we visited the rocket stove at CCAT to check on how it's doing and update the page a little. The stove is in decent condition but there are a few areas that the stove could be improved. The rocket stove has gone through a few very minor changes since its creation. Recently, it received a fresh paint job. Also, the chimney has been lengthened considerably. As you can see from previous pictures, the original chimney was rather short. The new chimney is much taller and has a cap on the top. We also left a laminated informational piece to hang around the chimney and let people know what the rocket stove is and information about rocket stoves in general.

Updated testing

We met up with Dan and tested the stove. It appeared as if the stove hadn't been used in quite a few years.

• The first step was to wash the cookpot
• Then, we gathered pieces of kindling 1' to 1.5' long. The kindling weighed a total of.44 lbs
• After that, we filled the pot with water and placed it in the skirt
• Next, we started burning the pieces of wood in the combustion chamber. We also added dead grass to the kindling.
• The water came to a rapid boil within 7 minutes and 25 seconds.
• The water's temperature was measured at 150 degrees Fahrenheit.

We observed a few problem areas. The vermiculite used to insulate the combustion chamber is old and could be replaced. Also, there are small gaps between the combustion chamber and the metal case of the barrel, which may have decreased the concentration of the heat around the pot and the low temperature of the boiling water. These gaps could easily be filled in by some kind of heat resistant sealant. Also, it was unclear if the addition of the longer chimney improved the flow of gasses or not. As noted earlier the chimney should be short, reaching just above the cookpot so the lengthened chimney might have actually hindered the flow of gases. Also, the bricks in the combustion chamber may need some replacing as well. If this stove was being consistently used, it would probably be a good idea to address these concerns as you would want your stove in prime running condition.

October 2014 update

Updated by Jacob Carroll-Johnson and Carlos A. Sanchez

It looked like the rocket stove has not been used in quite some time. Reasons for not using the rocket stove is easy of use. Its difficult to light and once it is lit it's hard to stay lit. The bottoms of pots get scorched. It also becomes very smokey when using. The weather has taken its toll on it. I was bummed out that we couldn't test it out and see actual results. We are planning on going back to do some testing and see how it compares with when it was first built.We will post results once we run some tests.

We proceed with the analytical analysis. The first thing that we noticed was the smoke flute and the laminated information were gone. Rust has taken its toll on the stove.The top and bottom have taken the most hit from it. There are some holes from the rust going all the way through the top. So the top will soon need to be replaced. The bottom also has been affected. It appears that the rust has eaten the metal, and is now really thin at the bottom. No holes yet but maybe in the near future. There doesn't seem to be much continuity of the rocket.Moving on to the combustion chamber. The heat resistant sealant that was used to seal the ceramic bricks is almost completely gone. The bottom brick is also in bad shape. When we wiggled the bottom brick we saw that only one big chunk moved. We also noticed that the back part of the combustion chamber had cracks.

See also

• Aprovecho Research Center
• Larry Winiarski's Rocket Stove
• WaterPod Rocket Stove

References