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CO2 enrichment for higher yields using Ecotechnics controls

PostPosted: Fri Oct 25, 2013 9:31 am
by teetee
Hi,

I found this very informative article to explain the use of CO2 in an indoor set up.
I must credit RPsmoke on Bubbleponics for the research on this and the next post. After that, I will show my set up.

Taking Advantage of CO2 Enrichment
by Isabelle Lemay, agr. and Melissa Leveille


Optimal photosynthesis, generally resulting in maximal growth and yields, is just one of the many benefits of CO2 enrichment in the garden. In order for your plants to really enjoy effective CO2 enrichment, it is important to do it the right way. The following article suggests different tricks to ensure these advantages are fully accessible to your plants.

Choosing an appropriate enrichment method for the garden

Certain criteria must be taken into consideration when choosing a source of CO2, such as the price, the impact on the garden’s climate and potential toxicity. However, bottled CO2 and combustion generators are the most effective and common way to enrich your garden.

The importance of CO2 distribution in the cultural environment

Once the ideal CO2 source is identified, the positioning of the equipment must be carefully studied to make sure the plants absorb the precious CO2 at maximum capacity. According to some research, the best results are obtained by injecting CO2 in the upper third part of the plants where photosynthetic activity is at its highest.

CO2 movement in the air

Several factors influence CO2 movement in the air, including some relatively simple physical principles. When these principles are understood, it is possible to foresee CO2 movement in the garden, and control it directly toward the leaf area.

The first factor to consider is CO2’s weight. At ambient temperatures, CO2 tends to drop as its weight is heavier than the air’s weight (composed mainly of nitrogen and oxygen). For example, at 77°F, CO2 weighs 66 ounces per three feet cubed in comparison to 42 ounces per three feet cubed for the air. This means that CO2 will naturally go down to the ground. A second physical factor that influences CO2 movement is the temperature. Hot air tends to rise and cold air descends; this is also true for CO2. This is why the cold CO2 from the bottle will normally go down while the hot CO2 generated by combustion will rapidly rise up to the ceiling.

The diffusion principle is also responsible for CO2 movement. Diffusion is simply explained by the fact that gas tends to take up as much room as possible. Generally, it will direct itself from a location where its concentration is elevated to another where its concentration is lower. Although this principle is applicable to CO2, this gas does not travel very far by simple diffusion.
The air movement also influences significant CO2 displacement in the garden. In fact, CO2 follows the air path, which can be created with a fan.

Here is an example to summarize the above statements. A garden is enriched with a regulated CO2 bottle. After the injection, CO2 tends to drop (weight and temperature) and then moves in the air towards the locations that are less concentrated (diffusion). Once CO2 is diffused in the air, it does not stay on the ground but instead follows the rising movement of the hot air (temperature and air movement).

Effective distribution systems

Regardless of which enrichment method is being used, good CO2 distribution in the garden is important so your plants can absorb it properly. To obtain a homogeneous CO2 concentration in the garden, it is beneficial to inject it at different locations. To do so, use several CO2 generators with average power in one room instead of one high flow rate unit. This same principle is also applicable to CO2 bottles. With bottled CO2, which tends to drop due to its weight and the temperature, it is logical and favorable to inject it lightly above the plants or directly at their third upper part. When CO2 comes from combustion, the generator’s location may vary; wherever it is, hot CO2 will rise up towards the ceiling anyway. However, it is important to avoid installing the generator directly on the ground to protect it against water damages or close to the ceiling to avoid fire hazards. Whatever the source is, it is beneficial to place it far from an exhaust fan to avoid wasting CO2 outside.

Not only is it important to install CO2 sources in strategic locations, it is also recommended to use rotating fans to create air movement that quickly directs CO2 towards the plants. For bottled CO2, simply placing a fan near the gas outlet will move and distribute CO2 evenly around the room and the plants (figure one). For CO2 generators, a ceiling fan can be used to mix CO2 in the air and to bring it down to the plants’ level (figure one).
Using fans is also really effective in renewing the air and CO2 around the plants. In just a few minutes, leaves can absorb all the available CO2 around them. Because this gas moves really slowly by diffusion and only on a short distance, ventilation is essential to provide the plants with a proper and stable concentration for their growth.

In the case of bottled CO2, another ingenious and simple system is to connect a perforated plastic tube to the regulator and install it above the plants. CO2 will then be vaporized trough the small holes and homogeneously distributed near the plants (figure three). It is easily possible to pierce the holes on the tube by placing it under water while injecting CO2. The holes’ size and location will determine the CO2 distribution.

A controller combined with an effective distribution system will maintain a precise and stable CO2 concentration in the garden. Like all other equipment, the controller must be installed at a logical location to be effective. It is only the CO2 sensor that has to be placed at a location representative of the concentration around the plants. Depending on the controller’s model, the sensor might be inside or outside the controller’s enclosure. It is best to install it in the center of the garden at a height that is equivalent to the upper third part of the foliage. This way, CO2 concentration will be steady near the plants and will perfectly fulfill their needs!

A good application of the advices mentioned above will surely have a positive impact on your yield’s quality and quantity. However, other aspects have to be taken into consideration for ensuring optimal plant growth and avoid wasting CO2.

Good climate management

In order to fully benefit from CO2 enrichment, all of the environmental parameters must be well managed. It is important to perfectly master your plants’ needs on every level—temperature, relative humidity, lighting, CO2 concentration, etc. The moment one of these parameters is no longer ideal, it becomes an obstacle to plant growth. In a garden enriched with CO2, it is important to consider that the best temperature for plants will be slightly higher than usual.

Effective gardening with CO2 requires careful planning and appropriate choices of equipments and layout, all based on the plant’s needs and the garden type. A predetermined plan for a perfect distribution system does not exist; the ideal plan varies for each cultural environment and is established according to a strict analysis of the location. Finally, the best CO2 enrichment system will only be effective if all of the plant’s needs are satisfied!
:grin:::::

Re: CO2 enrichment for higher yields using Ecotechnics contr

PostPosted: Fri Oct 25, 2013 9:45 am
by teetee
Wind, Earth, Water or Fire: Which CO2 Are You?
by Erik Biksa


There is little debate over the fact that increasing carbon dioxide (CO2) levels in the growing environment will increase growth rates, give bigger yields and reduce overall cropping time. There is varying information on what levels are optimal in different growth phases, for the type of crop and even in varying nutrient programs. Carbon dioxide can be supplied with wind (fresh air), earth (natural fermentation or bio-activity), water (liquid CO2; compressed gas) or fire (gas fired CO2 generators). Each method of delivering CO2 to crops has its own unique qualities, capabilities and with some methods, even limitations.

Growers who want to have the most productive gardens and biggest yields will first take the time to create an optimal and controllable growing environment for their crop. Only then will the grower be able to realize their crop’s full potential with carbon dioxide enrichment. The benefits attainable by supplementing CO2 levels in the growing environment will largely be determined by how accurately and how steadily the grower can maintain the elevated levels of CO2. There are also practical considerations which include cost, level of skill required and the overall controllability of the existing growing environment

Wind

For the best results when supplementing carbon dioxide, the growing area should be able to function as “sealed” as possible. I have been discussing CEA (controlled environment agriculture) methods for many years now. In short, a “sealed” or “perfect” grow room has minimal to no outside air exchanges.
The wind method of delivering CO2 to crops is found in traditional in/out style, mechanically vented gardens. By supplying a constant flow of fresh air through the canopy from outside air, then exhausting it out, CO2 is supplied at ambient (low) levels.

In this method, the highest levels of CO2 you can hope to achieve are ambient levels - the average CO2 level of outside air before it becomes depleted of CO2 by the crop for growth. Average ambient CO2 levels range from 350 to 650 ppm (parts per million). While this is sufficient to sustain average growth and flowering rates, for high yielding crops that produce at faster rate you will need more. To do so, the environment has to be enriched with additional levels of CO2. Enriched levels become defeated with constant air exchange as the CO2 is sucked out of the room (usually to ventilate heat away). This is why to achieve maximum yields with CO2 supplementation the grower needs to run a tighter or sealed environment.

The easiest way to construct a CEA environment is to use an air-conditioner instead of a vent fan in the grow room for cooling purposes. There are specialty air conditioners available that are highly suited for use in grow rooms. Otherwise, simple air conditioners, even “window bangers” can be modified for use in a sealed growing environment with carbon dioxide supplementation. Besides being able to maintain higher and more precise levels of CO2 in the growing atmosphere, the grower will have precision control over the grow room’s most important parameter - temperature.

To reduce electrical costs by cutting down on the frequency of cycling by the AC, growers can install or continue to use their air-cooled lighting systems. These still keep the environment “sealed” because the hot air removed by the reflectors from the lamps is sealed off from the growing environment by the protective glass. This helps to keep the additional CO2 in the room where it belongs, while removing heat from the largest source in the grow room - the lamps.

If an air-conditioner isn’t possible, go with the air-cooled reflectors and a “smart” environmental controller, such as the unit featured in this article. This way, the exhaust fans won’t need to empty the air out of the room as often to evacuate heat when using air-cooled lighting. The air cooled shades will keep most of the heat out of the grow room.
The exhaust fan(s) will only cycle on when the temperature or humidity set-points are exceeded. The “smart” feature of the controller will stop your CO2 enrichment from running (tank/regulator or gas fired generator) when the exhaust cycles, saving you from wasting money generating valuable CO2 that is being exhausted out with the hot air. This way, the air-cooled lighting will take away most of the heat, and the exhaust fan will need to cycle much less frequently, affording the grower a window to boost CO2 above ambient levels, greatly improving yields and growth rates. When the exhaust does cycle, you won’t be wasting valuable CO2 thanks to the integrated controller.

Earth

So now that we have discussed wind, let’s move onto earth. How does one get CO2 from earth? Well the truth is, decomposition and fermentation produce carbon dioxide, and are responsible for a portion of our ambient CO2 levels here on earth. While this method can produce some additional levels of CO2 in growing environments, it’s typically limited to being effective for very small scale gardens and less intensive growing environments.

There is little or no control as to the level of CO2 that is produced and dispersed by these natural processes, and the output of CO2 will vary through the biological process producing the CO2. To raise CO2 levels past ambient into the growth excelling 1000 to 2000 ppm range, you will need a very tightly sealed environment and will likely have to replenish your source of bio-carbon dioxide frequently. Also, to generate a significant and sustained amount of CO2 for the crop, you will likely need a large volume of the bio-materials used to create the process in the grow room. Unless you have a boundless room, the space in the growing room is more productively filled with plants. For example in a three foot squared grow tent, you will need to devote about 25 per cent of your floor area to a fermentation bucket or carboy going the route of fermentation to boost CO2 levels. However, note that using LED lights to decrease ventilation requirements and a five gallon primary fermentation tank in a three foot squared hydro hut allowed the author to achieve 2800 ppm of CO2 during the primary fermentation, which lasts just a few days. During the secondary fermentation, average levels were 900 ppm of CO2, lasting for about 10 days.

There are some innovative products that use a natural composting process to deliver small, but continuous amounts of CO2 to gardens. These can help to improve growth rates in smaller tightly sealed gardens. However, they are not controllable, and do not produce large amounts of CO2 on demand.

Most plants will not use carbon dioxide during the dark cycle, so the CO2 generated through Earth methods is somewhat wasted, although it is of no harm to plants to supply CO2 during the dark cycle.

Water

Moving up the ranks of effective CO2 supplementation for bigger yields, we arrive at water. For our purposes water will embody liquid carbon dioxide or compressed gas used in CO2 supplementation. Typically, this is supplied by either 20 pound or 50 pound tanks that contain liquid CO2/compressed gas. The tanks alone will not provide the increased garden performance levels that CO2 offers.

If you choose to increase your yields and growth rates with liquid/compressed CO2 tank, you will need a high quality “REG set-up,” which consists of a precision regulator/flow gauge and an industrial solenoid valve. The unit featured in this article is of extremely high quality and is relatively inexpensive when comparing to high-output gas fired CO2 generators. The flow rate is completely adjustable and gives the grower a visual indication that there is pressure in the tanks (you haven’t run out of gas) and indicates when the gas is flowing and at what rate. The little ball that floats in the set-up tells you exactly at what rate the gas is leaving the tank; allowing growers using timed CO2 to make more precise calculations. It’s fun to watch too!

You will either need a timer that controls both the frequency and duration of CO2 injections from the tank, or a carbon dioxide level sensor/controller unit to activate the solenoid in the REG set-up. The “smart” CO2 controller featured in this article allows growers not using infrared CO2 level monitors to dose CO2 into the growing atmosphere at controlled intervals and amounts. There are plenty of articles that describe how to perform the relatively simple calculations that will tell you how much gas to release to achieve the desired CO2 ppm level in the growing atmosphere. The grower needs to know their flow rate, desired CO2 levels and the volume of the growing area. The calculation will tell the grower how long the CO2 needs to be emitted and how often (duration and frequency) Remember that “smart” integrated controllers will shut off CO2 if exhaust systems are active; saving your CO2 for better use.

If you run a sealed environment, you will get the most out of your CO2 set-up by controlling CO2 levels with an infrared CO2 monitor. This allows the grower to create exacting levels of CO2 in the plant environment efficiently, taking the guess work out of CO2 supplementation. Prices vary, and are dependent on the number of features and level of control you desire. Some units allow you to control more than one REG or generator from the same unit (dual probes), while others may use “fuzzy logic” to improve efficiency. Always make sure that the unit you choose can be serviced by the factory or place of purchase. CO2 monitors are expensive precision instruments that may require re-calibration or fine-tuning from time to time.

Overall, bottled CO2 gas is relatively safe to use; make sure you use the beverage grades and avoid welding grades as they contain impurities. The CO2 emitted from tanks adds no additional heat or significant humidity to the growing area versus gas fired generators. The gas is relatively easy to disperse through the plant canopy. Simply connect one end of the specialty tubing supplied with your REG set-up to a strategically positioned oscillating fan(s), and the other end to the REG set-up. Plug the REG into your CO2 sensor, timer or integrated environmental controller, and your plants can begin to grow at accelerated rates and give you bigger yields. Bottled CO2 released is heavier than most air and can settle, so it needs to be kept stirred and blowing across the plant’s leaves during the light cycle with fans.

Bottled CO2 works great for smaller well sealed grow areas with minimal air exchanges. It does require frequent replacement, which means lugging large heavy gas cylinders that look like missiles here and there. The cost of adding CO2 to the growing environment is highest using bottled CO2 amongst wind, earth, water and fire methods described here. The initial equipment purchase costs are moderate, especially if using a timed systems; it’s the frequent replacement of the heavy tanks that becomes costly and laborious. If you have never tried using CO2 in your garden before, a tank, good quality REG and integrated controller are an easy and less expensive way to give it a try. Look for a controller that can also accommodate an infrared ppm sensor so that when you are ready to upgrade, you can still use your existing equipment. Your plants will begin to grow at accelerated rates, so pay extra attention to your watering and feeding methods.

Fire

As we move to fire in our CO2 enrichment hierarchy, consider fire to be a friend and beneficial elemental state, although not to be toyed with or taken lightly. Gas-fired CO2 generators are our fire in the scheme of yield boosting CO2 supplementation.

To supplement CO2 levels in the growing environment, CO2 generators or “burners” ignite fossil fuels such as natural gas (NG) or propane (LP) to create a highly clean and efficient combustion to burn oxygen out of the air and produce carbon dioxide in abundance as a result of the fire process. The combustion also creates warmth and moisture in the air. In sealed environments running with air-conditioners, the extra moisture in the air is welcome to help keep humidity levels at optimum, as ACs tend to de-humidify the air when operating. In greenhouses or cooler months, the additional heat generated can be welcome, while in most situations it will require cooling by AC. Cooling the growing area with exhaust fans defeats fire as an efficient means to supplement CO2 levels for plant growth; unless the exhaust fans cycle infrequently, including when the burner is operating.

CO2 burners have been around for some time and the newer models are quite safe to use when operated as specified by the manufacturer. Never use a NG burner on a LP supply or vice versa. When installing, inspect all joints and lines for leaks by brushing with a soapy solution and looking for air bubbles. Always keep propane tanks outdoors, and not inside. Long hoses are available to supply burners from tanks outdoors.

A high quality CO2 burner, such as the one featured in this article, is recommended. The first generation(s) of CO2 burners helped early growers get bigger yields. However, by today’s standards, they are fire-breathing dragons of yore. Modern CO2 burners use electronic ignition systems instead of standing pilot lights. This saves on gas used for combustion, and creates an additional level of safety. Do not use just any source of flame to try and create CO2 in your growing environment. The results could be deadly; you are literally playing with fire. Modern CO2 burners like the one pictured in this article have oxygen sensors, tip-over shut-offs and many other features that allow them to be used in closed environments with a relative level of safety.

The flame produced by high quality specialty CO2 generators is pure blue, indicating that few impurities will be released with the CO2 during combustion. Flickers of orange or yellow in the flame indicates the combustion process is inefficient, and may produce gases like carbon monoxide (CO), which can be very harmful or even deadly to you. If combustion is “dirty” or inefficient, ethylene gas may be produced, and just a few ppms of it can harm or kill your crop.

For some growers, using water-cooled heat exchangers in conjunction with their CO2 burners helps to reduce cooling requirements in the growing area associated with the extra heat generated during combustion to produce CO2. They tend to run through quite a bit of water for cooling in a drain to waste cooling system, or require large volumes of water and tanks that need to be cooled if you are running a “closed” liquid cooling system.

For the most efficient and trouble free CO2 enrichment set-up, a high quality CO2 burner and infrared monitor/controller is recommended if you are gardening on any kind of scale. While fire is not the least expensive route to take, once set-up and installed, you will just need to refill the propane tank (kept outdoors) occasionally. Better yet, if you have natural gas available to you, buy a NG gas CO2 burner, and have a qualified technician install a gas supply directly to the burner that has an on/off valve in the supply for safety. From there, all you will need to do is try and keep up with the accelerated growth rates of your crop!

Conclusion

So, what kind of CO2 do you rely on to help determine your yield levels? If you are at the wind level, consider moving up to earth or water; you will notice a big difference in your rate of production. If you are a professional, or even a hobbyist looking to get bigger yields and reduce cropping times, fine-tune or upgrade your set-up to the water or fire level; once you have, you will never look back. Remember that to get all the benefits associated with elevated CO2 levels, all of the parameters in your grow should be at optimal levels first. As you start to incorporate CO2 into your game, take the time and possibly even a little extra expense to do it right. This way, all you are left to do is to try and keep up with accelerated growth rates that can drive your crop to bigger yields.
:grin:::::

Re: CO2 enrichment for higher yields using Ecotechnics contr

PostPosted: Fri Oct 25, 2013 10:53 pm
by teetee
CO2 ENRICHMENT GUIDE


Carbon dioxide (CO2) is used by plants in photosynthesis, or the conversion of water, atmospheric carbon dioxide and light in the plant's chloroplasts into food energy (simple carbohydrates), with oxygen as a byproduct. Resins and saps in the plants stems and branches then transmit this food around the plant to promote growth, reproduction and prevention of disease.

Photosynthesis stops at night, thus plants do not use CO2 during the night, or lights-out stage. Although enrichment of the atmosphere during the night cycle will not harm the plants, efficient CO2 systems are regulated so that when the lights go out, CO2 emissions stop.

Ambient air at sea level contains approximately 350-500 ppm of carbon dioxide. Higher altitudes and rural locations typically have a lower presence of CO2, while lowlands and urban areas have a higher presence. CO2 can be measured, in parts per million (ppm) of air, using an inexpensive devices available in hydroponics and garden shops.

It is thought that many plants evolved in a prehistoric atmosphere containing much higher levels of CO2. Because of this phenomenon, plants today are able to process much more CO2 than they are normally exposed to. Most gains in the rate of plant growth, higher yields, and stronger, healthier plants are made at CO2 levels 3 to 4 times the normal atmospheric level of 350 parts per million. Most plants don't grow much faster in levels greater than 1500ppm, and depending on variety, plants can be damaged in atmospheres containing more than 2000ppm CO2. Low levels of CO2 (below 200) have been show to halt vigorous growth, even when all other conditions are ideal. Because of this, any enclosed space requires replenishment of the internal CO2 as it is used by plants, either from ventilation or from CO2 supplementation.

Temperature, humidity, and CO2 concentrations form a triangular relationship in a greenhouse or indoor grow. If all 3 factors are not in equilibrium, there is a risk to the plant in terms of stunted growth, toxicity, or death/disease.

Standard growing conditions typically include concentrations of CO2 at 300-500 ppm, temperatures between 65-80°F, and relatively low humidity (20-40% rH).

Studies have shown optimal growth and yields at 90-95°F, 1,500 ppm CO2, 45-50% relative humidity, 7,500-10,000 lumens/square foot of light, and vigorous air movement both above and below the canopy. CO2 enrichment under 80°F, under 7500 lumens/sf, or above 50% humidity is NOT recommended because plants will not be conducting photosynthesis quickly enough to benefit from the enrichment.

Internal air movement in the grow room is critical to CO2 enrichment. Carbon dioxide is a slightly heavier molecule than other molecules floating around in the gaseous mixture we call air. Thus, CO2 enrichment without air movement will result in the gas settling out of the atmosphere before it has a chance to reach the plants. High temps and humidity without air movement can also encourage mould and bacteria growth.

To calculate the amount of Carbon Dioxide needed to enrich a room to 1500 ppm, first calculate the volume of the growing space. For instance, an 10x8 foot room with an 10 foot ceiling would contain 800 cubic feet of space. Determine the CO2 needed to enrich to 1500 ppm in a room with ambient CO2 of 300ppm (ie adding 1200ppm) by multiplying the volume of space by .0012.

800 x .0012 = 0.96

Thus, 0.96 cubic feet (or rounded up to 1 cu ft ) of carbon dioxide will be needed to enrich this room at 1500 ppm. That would be 27 Litres in the UK.

The rate at which carbon dioxide needs to be replaced is purely a function of how much ventilation the space receives and how many plants are consuming CO2 in the grow space. Only testing monitoring will ensure CO2 levels remain somewhat constant. Grow rooms that rely heavily on external ventilation to control temperatures or smell should not consider CO2 enrichment, because any gas introduced to the space will be blown out as quickly as it's created. A sealed room that relies on no external ventilation is ideal for CO2 enrichment. Since the ideal temperature for CO2 enrichment is much higher than normal, growers who employ this technique will need much less ventilation (if any).

For those who still want or need external ventilation, CO2 enrichment will only succeed if exhaust and enrichment are timed and set on opposing cycles. For instance, in a flowering room an exhaust fan timed to operate during the night would not conflict with CO2 enrichment during the day, when plants can use the additional gas. In vegetative growth rooms, the fans and enrichment would need alternating cycles to make enrichment worthwhile. For those growers using unregulated sysems, CO2 output should be adjusted for both speed and volume to make up for the exhaust.

There is some anecdotal evidence that charging nutrient solutions with seltzer cartridges will encourage plant growth in some hydroponics systems. The CO2 is released into the atmosphere as a byproduct of nutrient movement in the hydro system. This method has not been scientifically proven, nor would not be effective in aeroponic systems where nutrients are largely contained in separate tubs from the leaves and branches of the plant. Spray ring and ebb/flow systems may have the best potential for success with this method.

I have also seen good reports posted regarding the use of seltzer as a foilar spray twice a day as the CO2 in the seltzer can be absorbed directly into the leaf. Club Soda contains more sodium and may clog the stomata and should be avoided. It is advised to wash the leaves with straight water after 2-3 applications. One factor regarding the use of Seltzer water is that humidity levels are raised. You must vent during the dark cycle to prevent the raised humidity causing mould and increased internode length. I wouldn't have a clue what Seltzer is in the UK, but I think simple carbonated water or sodastream water might come close, Club soda is much the same with added salts and minerals... Perrier etc. The other factor to remember is to switch off lights or spray away from lights when using it.

METHODS OF CO2 PRODUCTION

Tanked CO2

Tanked CO2 is by far the most reliable and controllable method of CO2 enrichment. Bottled CO2, usually available from welding supply and bottled gas vendors, is metered out via regulators and solenoids. It is possible to very finely regulate the amount of CO2 in the atmosphere using technologically advanced digital regulators. In many areas, licenses or permits are required to obtain bottled compressed gasses due to safety regulations. In the UK, CO2 is used in the food and drink trade (beer lines), in aquariums or for MIG welding. The CO2 supplied for welding is not as pure as the aquatic and food grade cylinders. Searching around on google will locate your nearest CO2 supplier, I found BOC potentially useful but then found some hydroponic shops that are wising up to CO2 and who can supply and refill cylinders no questions asked. If that's not possible where you live, you could have a word with a friendly pub landlord and 'borrow' a CO2 cylinder from them. CO2 is also used in Aquariums to keep live plants and various creatures alive. A bit of fake interest in aquatics can also get a no hassle CO2 cylinder. I was lucky enough to have a 3kg cylinder posted to me from an Aquatic shop. PM me if you need details.

Advantages
-Very fine control of CO2 using regulators
-Easy to automate, hassle free once set up

Disadvantages
-High initial cost of equipment
-Logistics of delivering and returning heavy bottles to a secure grow area
-The tank becomes a deadly projectile in a catastrophic failure, or can cause a significant and dangerous explosion in a fire.
-Rapid, unexpected release of CO2 can cause over-enrichment and asphyxiation of room occupants.
-Permit/license requirements may make bottled gas difficult to obtain

Combustion

Fuels such as ethyl alcohol, natural gas, or propane produce CO2 as a byproduct of combustion. Burning of one pound of clean burning heating fuel will produce 3 pounds of carbon dioxide gas, 1.5 pounds of water vapor, and approximately 22,000 BTU of heat.

Devices which help attract and kill mosquitoes in outdoor yards use propane fuel tanks to create carbon dioxide. The insects are attracted to the CO2, which in nature is an indication of a food source. These devices burn propane in a tightly regulated, low temperature combustion chamber. Although these would probably be the lowest temperature application of this method, any indoor storage of propane, natural gas or other bottled, explosive gasses is highly discouraged.

Ethyl alcohol (available as denatured alcohol in hardware stores) is a readily available material and can be safely burned indoors in small stoves or lamps. Ethyl alcohol is also the primary reactive component of Sterno and similar gel fuels.

In our sample room 10"x8"x10", would need to burn around 8 ounces of ethyl alcohol per day (a little more than a cup) to enrich a completely sealed room. The amount of CO2 needed (and thus fuel) would increase with any supplemental air changes. There is some evidence that active combustion can help control odors in enclosed spaces.

Coleman stoves, bunsen burners, portable propane space heaters, and other similar devices are all potential sources of carbon dioxide as long as they are used safely.

Advantages
-Inexpensive to set up, depending on method chosen.
-Heat can be beneficial if temps are low, such as in a cold basement grow room.
-Output can be regulated by size of flame
-Can provide slight odour control.

Disadvantages
-Open flames in enclosed spaces create a fire hazard
-Additional heat produced by combustion adds to heat already produced by HID lighting.
-Can be difficult to burn enough fuel to achieve optimal enrichment without adverse side effects, such as carbon monoxide.
-Indoor storage of bottled fuels is potentially dangerous.

Fermentation

It is widely known that CO2 is a byproduct of fermentation. CO2 is the gas found in bubbly beverages, such as champagne and beer. The same process that "carbonates" these beverages can be harnessed to create CO2 for a grow area. A pound of sugar will ferment into approx. 1/2 lb of ethyl alcohol and 1/2 lb of CO2. A room 10"x8"x10" would need just over 1lb of CO2 per day. This means that about 50 lbs of sugar will be used over 6 weeks (assuming that not all sugar is completely converted to alcohol).

To get the process started, mix a pinch of yeast, 12 ounces of warm water and a half-cup of sugar and keep warm and covered until bubbles form in a day or so. Use this mixture to inoculate the main bin.

To create a yeast bin mix, dissolve 3 lbs of sugar per gallon of boiling water. Cool the mix to 80°F before adding the yeast. Locate a container with a tightly fitting lid. The lid should be equipped with a hose to direct CO2 gas towards a fan for distribution into the space. Increased air pressure in the bin will force the gas out of the hose.

Both canister and lid should be thoroughly cleaned with hot soapy water and rinsed well before use. Start off the bin a little more than half full (10 gallons of water and 30 lbs of sugar). Every week, add another gallon of water and 3 lbs of sugar. The yeast bin must remain at 80-85°F for the reaction to continue.

To monitor activity and prevent contaminants from entering the bin, create a fermentation lock by placing the end of the hose into a glass of distilled water. The bubbling water will be an indicator that there is still a reaction in the bin and prevent bacteria from entering the bin through the hose.

Our bin will need to be completely replenished every 6 weeks, or when the bubbling slows. A simple taste test will tell if the bin needs replenishing. If the taste is sweet, there is still sugar in the water and the reaction should continue. If the taste is dry like wine, the bin is mostly alcohol and should be replenished. Some growers preserve a cup of liquid from the old bin and use to inoculate the new bin, however if an infestation is starting to occur, this can contaminate an otherwise fresh bin with bacteria. It's just as easy to inoculate with new yeast as above, and extra yeast stores easily in the refrigerator for months. Corn sugar (available at wine making shops) is a less expensive fermentation medium than regular cane sugar. Other fermentation mediums can be used depending on materials cheaply and readily available to the grower. Corn syrup, maple sap, even old fruit juice can be fermented, although with increased odours and more waste cleanup when the bin is refreshed.

Advantages
-Easy to create with simple materials
-No safety dangers
-Inexpensive materials when purchased in bulk (sugar)
-Ethyl alcohol byproduct can be siphoned off and burned in alcohol lamps for supplemental CO2 enrichment

Disadvantages
-Difficult to regulate
-Fermentation can produce odours
-Large yeast bins are heavy and hard to move.

Dry Ice

Dry ice is nothing but carbon dioxide in its solid form. Dry ice is commercially available nearly everywhere for industrial, medical, and theatrical (fog machine) applications. One pound of dry ice is equal to 8.5 cubic feet of gaseous CO2. Create a CO2 chamber by poking holes in the sides and top of an insulated box, foam cooler, or similar container that can insulate the material from human skin and plants. The box also helps insulate the solid ice so that it vaporizes more slowly. Ideally it should take an entire day for the chunk of ice to vaporize, although smaller chunks may need to be added at intervals through the day to maintain 1500 ppm.

Some growers place their containers of dry ice directly over grow lights. The falling CO2 bathes the plants beneath them and also helps control temperatures from hot lights.

For our 800 CF grow room, about 1.3 lb (0.6kg) of dry ice per day would be needed to keep CO2 at 1500 ppm. At £3-4 per kilo, dry ice would be a very cost effective solution. Storage of dry ice in a home freezer will slow it's vaporization, but dry ice is hard to store ahead because doesn't have a long shelf life. Not many homes have freezers capable of maintaining -109°F.

Advantages
-Inexpensive, widely available material
-Easy to construct and maintain
-No risk of catastrophic failure
-Dry ice has slight cooling effect

Disadvantages
-Impossible to regulate evaporation
-Must be used immediately - has no shelf life
-Can harm skin if handled without gloves.

Soda/Acid

Baking soda and acetic acid solution, such as white vinegar (5% acetic acid), will bubble and foam when mixed. The bubbles produced are carbon dioxide. Unfortunately, large quantities of materials are required to produce carbon dioxide adequate for enrichment, making this solution viable only for very small closet grows.

To produce 1.25 lb of CO2 every day for our 800 cu ft test grow room, we would need to mix about 2.5 lbs of baking soda with 5 gallons of 5% acetic acid vinegar. As you can see, the costs for baking soda and vinegar would add up quickly. For a small closet or cabinet operation, it may be a workable solution though. A small drip setup can be placed on a top shelf of the closet, with the CO2 cascading down onto the plants (so long as it's not sucked out by vent fans).

Mixture of appropriate amounts of vinegar and baking soda will quickly fill a small room to acceptable enrichment levels. From there, a simple drip irrigation system can be created to steadily regulate CO2 levels, using a reservoir of white vinegar suspended over a tub of baking soda. A hose with a small pinhole is a good way to create a steady regulated drip. Calibrate the drip with a pushpin or small nail until the hole allows the desired amount of vinegar to drip through in a 24 hour period. An added bonus to this method comes from baking soda's odour neutralizing effect when left open to the air.

For slightly larger operations, 1 lb of carbon dioxide can be created from 2 lbs of baking soda and 1/2 gal of 33% muriatic acid, which is an chemical additive used in swimming pools. Although this is more cost effective, it is still more expensive than some of the other methods mentioned. Muriatic acid (a.k.a hydrochloric acid) is also highly caustic which can cause serious chemical burns if mishandled.
There are commercially available machines which produce CO2 this way, by mixing baking soda with muriatic acid using mechanized agitators. These units do not have regulators, solenoids, or pressurized compartments to store gas during the off cycle. Any jug made from plastic that can withstand a caustic material such as muriatic acid would be equally effective.

Advantages
-Easy to set up with simple, readily available materials.
-No risk of catastrophic failure
-Slight odour control benefit from baking soda.

Disadvantages
-Difficult to regulate during off cycle
-Can take a long time to build up a proper CO2 enrichment
-Materials can be expensive over time unless purchased in bulk.
-Some chemicals can be caustic.

Breathing

The natural breathing of air by people is also a way to contribute carbon dioxide to an enclosed space. This is the reason why people say that talking to your plants makes them healthy, even HRH Prince Charles is a fan... he is basically a portable CO2 generator (with a nice suit and a fancy crown). Some quick calculations show that one person breathing can actually provide a significant amount of CO2. Although the total lung capacity is approximately 7 litres, the natural tidal volume (each normal breath at resting) is about 0.5 litres (5000 cubic centimeters) per breath.

To convert cc to cubic feet, multiply by 3.531 x 10^-5

0.00003531 x 5000 = 0.17655 cubic feet of air

Since each breath made at a rest is 5% carbon dioxide:

0.17655 cu ft air x .05 = .0088275 cu ft of carbon dioxide
5000cc x 0.05 = 250 cc CO2
And since a person breathes approximately 14 times per minute at rest:

.008275 x 14 = 0.123 cubic feet of CO2 per minute.
Our room requires 1cubic foot of CO2 to reach 1500 ppm, which it will attain after only 8 minutes of normal breathing. However, that enrichment is quickly absorbed by the plants. Assuming that we require 1 lb (8.5 cu ft) of CO2 per day for our 800 cu ft grow room:

8.5 cu ft / 0.123 cu ft per minute = 69.1 minutes

Thus to enrich our room to 1500 ppm day, one average sized person would need to spend approximately 70 minutes per day in the grow room assuming the room was completely sealed. Spending this much time at once could elevate carbon dioxide to unhealthy levels, but several stops in the grow room spaced out during the day (perhaps 35 minutes in the morning and 35 minutes in the evening) would keep CO2 concentrations elevated to optimal levels.

Of all the methods mentioned, breathing for CO2 enrichment is free and requires no special tools, additives, equipment, or skills, apart from those required too make and smoke a joint. Breathing produces no unhealthy byproducts or hazards. Most gardeners spend a good amount of time in a grow area looking over the plants for bugs/disease, pruning them, mixing nutrients, admiring, etc. Entry to the room should minimize CO2 loss, through an airlock for example. As long as the space is well sealed and the air is vigorously circulated, normal breathing could produce all the C02 needed to enrich a small to medium sized room if it's visited and tended daily. One of the other supplemental methods can make up for times the gardener is away from the room for extended periods oftime. Working in any enclosed space requires caution and alertness to avoid asphyxiation.

Advantages
-Requires no tools, equipment, or setup
-Free
-Byproduct of being in the garden working

Disadvantages
-Multiple stops into the garden daily are required
-Slight risk of asphyxiation from being in an enclosed space too long
-Entry to room without an airlock will eliminate any gains.

Cost & Security Benefits of CO2 Enrichment

Plants in a CO2 rich environment can withstand and need much higher temperatures to derive any benefit. Inversely, CO2 enrichment can help mitigate ventilation and air conditioning challenges in grow rooms, common challenges faced by growers looking to minimize costs and maximize security.

Ventilation to the outdoors is a weak link in any secure grow operation. Exhaust to the outdoors can be detected by close neighbours, especially for growers in townhomes and apartment complexes. In many areas, a tip from a neighbour and detectable smell to the local constable or sheriff could constitute "probable cause" to get a search warrant. CO2 enrichment eliminates the need for excessive exhaust and thus the need for this breach in your security.

The primary operating cost of a residential grow operation is electricity. Reliance on high intensity discharge lights, fans, humidifiers, and pumps for hydroponic systems can nearly double a residential electric bill. Cooling a hot grow area to 75-80°F for normal growing adds another important but potentially expensive challenge. In many older homes, this could require additional electrical circuits, since each standard (15 amp) residential circuit should only power devices totaling about 1500 watts. CO2 enrichment eliminates the need for additional cooling above what's needed to maintain 95°F.

Notes & Warnings

CO2 is widely considered to be a "greenhouse gas", which is thought to be responsible for trapping the sun's radiation in the atmosphere and causing global warming. Commercially available CO2 is the by-product of industrial applications which reclaim gas that would have escaped into the atmosphere anyway. CO2 produced from combustion, fermentation or other means further increases the amount of CO2 in the atmosphere, albeit minutely. Enrichment with reclaimed CO2 is a more environmentally responsible method, however it is also the most expensive and logistically difficult.

Although CO2 is not a deadly gas, it's presence in an enclosed space can deplete the atmosphere of oxygen needed for human occupation, causing asphyxiation. Signs of asphyxiation include weakness, lethargy, dizziness and loss of consciousness. If a grower notices any of these signs for any reason, immediately leave the room and go to a safe space. If these signs then subside, the CO2 in the grow room is too highly concentrated and should be vented immediately.

Many of the methods described in this guide can be harmful or fatal if used improperly. The grower should use extreme caution when using any volatile compound, flame, or hazardous material. Consider emergency situations when designing your system. For instance, bottled gasses will explode or become deadly missiles when punctured or heated by fire. Fuel vapours in the atmosphere can explode suddenly from electrical arcs, open flames, even static electricity. Asphyxiation resulting in unconsciousness and death can occur quickly when a room is over-enriched. If you suspect any form of danger, get to safety first. No plant, CO2 system, or even a whole house is worth a human life.
:grin:::::

Re: CO2 enrichment for higher yields using Ecotechnics contr

PostPosted: Sat Oct 26, 2013 10:02 am
by teetee
That was a lot of theory, but hopefully from a different point of view, and with any luck, there's something for everyone to try there.

I went for a bottled gas set up, as I have built a climate controlled wardrobe, and wanted to be able to 'dial in' as many of the growing parameters as possible for the maximum yield. The cabinet is detailed in another thread on this site.
viewtopic.php?f=9&t=380

My Hydro shop is very well stocked, and had a variety of solutions. There were plenty of different fan controllers,some more sophisticated than others split into two main groups, one group were primarily for extraction purposes, the other group had other functions, such as humidity control, and more importantly, CO2 controls.

Ecotechnics make a fan controller and 2 separate CO2 controllers.
The 1st controller is the Ecotechnics Unis controller, which is a simple piece of kit that you can enter your room size, and it will dispense the correct amount of CO2. Unfortunately, it doesn't measure ambient CO2 levels, so it just keeps on pumping out CO2 based on ambient CO2 levels of 300ppm, even if the reality is much higher. It keeps on dosing even if the fans are venting, resulting in wasted CO2.
The Unis kit with fan controller and gas regulator is £304.

The 2nd controller is the Ecotechnics Evolution. The controller can operate with or without the CO2 sensor and can be used either with bottled CO2 gas or with a gas burning CO2 generator. In addition to this the controller can be interfaced to most external thermo/hygrostats for improved environmental control for rooms from 1 m3 to 999m3.
This kit includes the Evolution N.D.I.R. CO2 Sensor witch uses non-dispersive infrared sensing technology for fast accurate CO2 monitoring. This sensor is highly accurate and also highly affordable being less than half the price of similar products on the market.
The full Evolution kit is about £750, and includes the Ecotechnics fan contoller, N.D.I.R. CO2 sensor, and Ecotechnics gas regulator.
P1030682.JPG

P1030683.JPG

P1030680.JPG
The blue ball is the CO2 sensor, and the microphone shaped thing is the temp and humidity sensor.


Another brand of CO2 controller is the AutoGrow IntelliClimate Controller with 6 Relay Boxes and one CO2 sensor. The IntelliClimate considers itself to be the ideal climate controller for grow rooms of all sizes. It controls temperature, humidity, lights and CO2 in a unified way to obtain the best possible growing climate. It does all this while minimizing waste of CO2 and electricity. A PC interface provides a new level in user friendliness allowing growers to easily choose the components they are using, set the parameters for use and design their own data logging. Once they have selected the components they are using (fans, air conditioner, CO2, dehumidifier, humidifier, fogger, multiple light banks, outside temp sensors, intruder alarms), there are three choices :

1.AutoSet by Scheduling – This is the most accurate to use option. You simply click on the scheduling tab and fill in the boxes with light on/off times, day and night temperatures, acceptable humidity and CO2 requirements. You can lay out your entire crop cycle in one sitting, with the IntelliClimate changing your settings in accordance with your schedule.

2. AutoSet by Growth Stage – As your plants mature from seedlings into full vegetative growth and then into harvest, you simply click on the “growth stage” pull down menu and choose between five different growth stages: Cutting, Vegetative, Early Flowering, Late Flowering and Pre-Harvest. The IntelliClimate is pre-programmed, utilizing years and years of commercial greenhouse climate control experience.

3. Manual – This setting is for growers who like to tweak their settings on a regular basis, responding to the most current grow room conditions. In this setting, you decide your light timing, temperature settings, humidity settings and CO2 ppm manually, giving you the ability to change it easily.

Once you have the basic set up done, the IntelliClimate will do the rest for you. It costs £1500, and requires the Gas regulator to be purchased separately.

The 3rd and final brand available is the Harvest-Master pro Plus Climate Controller inc CO2.

It has temperature, humidity and CO2 sensors and provide 16 outputs to control lights, exhaust fans, CO2, cooling/Air Conditioner, heating, humidifier, dehumidifier and more options of your choice including intruder alarms and pH dosers. It can also send updates to your mobile phone.
It will call you for an alarm condition - overheating, low water / nutrient levels, or for intruders. (Available in countries with GSM networks only).
It can call you back with current Temp., Humidity, CO2 level, Day/Night time and what devices are operating.

The Harvest-Master "Pro Plus " Controller costs £1550 as a basic, requiring the CO2 regulator to be bought separately.

I would love to have had the Harvest-Master or the Intelliclimate, but as the Ecotechnics was half the price, and looked very user friendly, so I made it my choice. Not a bad choice but already I am aware of a few limitations:

1. It is not possible to set lights out and mimic lower temperatures at night.
2. The CO2 controller has a daylight sensor which means the unit HAS to be positioned inside the grow area. Some growers prefer not to have electric controls inside the grow area for numerous reaons such as prevention of shock, reduced reflective surface available etc... In the end I was lucky enough to have my esteemed buddy Godzilla make me a custom LED to mimic daylight for my CO2 sensor.

Anyway, All I had to do was decide how to distribute the CO2 in my cabinet. CO2 is an acidic gas, and as a result, can erode some plastics, meaning normal PVC tubing cannot be used. I sourced some FEP (fluorinated ethylene propylene) tubing with an 8mm indernal diameter, to fit the nozzle on the regulator. I made a loop of tubing using an 8mm T connector and had a hose trailing off the T piece to the regulator and gas cylinder. I punched 4mm holes (using a punch designed to make 4mm holes in irrigation systems) in the loop to allow the gas to escape. Finally, I made the loop tight enough to grip around my Helios light, so that the CO2 is dispersed over the canopy of my plants.
P1030679.JPG
Zoom in and you will see small holes on the inner aspect of the clear plastic tube that runs around the perimeter of the Helios light. On the right is the T connector with the black flexible hose running up and out of the cabinet back to the gas cylinder

I used the more flexible black tubing to connect the loop to the regulator, it was too thick to make neat holes in for the distribution, and as the FEP tubing was thinner and clear, it seemed a better choice inside the grow chamber. The white cable is the electrical connection from the controller to the solenoid on the regulator, this simply opens and closes the valve to allow gas to flow. I positioned the cylinder outsiide the cabinet to the side, behind my water chiller (the black pipes in the foreground are from the chiller).
P1030687.JPG

To redistribute any CO2 that had settled at the bottom of my cabinet, I placed a 9" fan (quieter than the 6"clip fans) on the floor pointing upwards.
P1030685.JPG

This is how the Ecotechnics system is wired up:
ecotechnics set up.jpg


Configuring the system is quite easy, you set the room volume, the level of desired CO2 and select various options regarding fan cycles, and away you go.
I found that by disabling the humidity control there was less venting, which improves the economy of my precious gas.
Being a small, closed environment, I initially had issues about maintaining temps in the 80s as I needed almost constant extraction to keep the temps from hitting the 90s. With CO2, I need temps in the 90s anyway, so using CO2 means less need for venting.

I will carry on using the Ecotechnics system for a while then upgrade. Who knows, someone might bring out a control set up with a timelapse camera and oxygen sensors etc (come on Godzilla mate!).
:grin:::::

Re: CO2 enrichment for higher yields using Ecotechnics contr

PostPosted: Sat Oct 26, 2013 12:28 pm
by ledbud
very good info teetee bro.
:cool: :grin:::: :grin:::::