Updated: Jun 20
What a warm pleasure to see you back on the Orisha blog!
The summer season is coming to an end and transitioning to more autumnal harvests. By the way, how was your season? Did you face any particular challenges? Did you have any good experiences? I would love to hear all about it! Don't hesitate to write me by email (firstname.lastname@example.org) or via our social media.
Anyway, the temperature is dropping, but we still need to keep all the buildings heated. In a winter climate, greenhouse production comes with its own set of challenges. Considering that the most popular crops require high temperatures, the energy bill goes up quickly.
Propane heating is notoriously expensive and not environmentally friendly. Many greenhouse growers are increasingly considering biomass heating.
You may be asking yourself, "But Sarah, what is biomass heating?"
In energy terms, biomass refers to any living mass from which energy is obtained through combustion or fermentation. In the case of greenhouses, a frequently used source of biomass is forest biomass. It comes in the form of logs, chips or wood pellets. This biomass is burned in a boiler.
"A boiler? I don't get it, Sarah, we usually use a furnace right?"
Well yes and no! There are generally two common mechanisms to help you heat your greenhouse: the equipment that heats the air, called a furnace, and the equipment that heats the water, called a boiler.
The wood is burned in the boiler to heat water.
The heated water is distributed to the greenhouse via a piping system.
The heat is transferred to the air either by radiation from the pipes or via a heat exchanger.
To optimize its life span, this kind of equipment should be checked annually and cleaned occasionally: take down the unit, clean its exterior surface, clean/inspect the seals, etc.
In this article as well as in parts 2 and 3, I will focus on two pieces of equipment in particular by presenting you the experience of its user:
The outdoor log boiler.
The outdoor wood chips boiler.
WHY CHOOSE BIOMASS HEATING?
Inexpensive or even free fuel.
Forest biomass is one of the easiest fuels to find. For free or for less. Many producers can find sources that offer them free wood (spoiler alert: this is the case with our two testimonials in parts 2 and 3)! Also, due to the low cost of fuel, the return on investment is quick when a large amount of energy is needed.
Low CO2 emissions
Compared to heating with fossil fuels, the long-term effect of biomass heating on the environment is limited, but still present. However, it should be noted that the key to keeping Co2 emissions low lies in implementing sustainable and responsible forestry.
The price of biomass heating equipment and its installation is quite high. We are talking about projects averaging around $30,000 and more. The initial cost is important, but it is a long-term investment that will last for at least twenty years.
You will need to ensure that you have at least 6 to 8 m² of space for the installation of the boiler and the storage of the wood.
Clean energy, but…
Although wood is considered renewable energy, it is not as renewable as solar or wind energy. It takes decades for the forest ecosystem to recover. In addition, burning wood can lead to high levels of particulate matter in the air. These particles have an impact on air quality and your respiratory tract. It is therefore important to make sure that you have an installation with a particulate filter
"It's great to know all this, Sarah, but where do I start?"
PLANNING MY PROJECT
Form of the fuel and its source
The shape of your fuel will have an impact on your final heating equipment. Some equipment will be more fickle with their fuels than others. Wood is the most common, but you may make a different choice depending on your needs and the fuels available in the vicinity. Here are some forms of fuel :
Construction and demolition debris (wood derivatives)
Agricultural waste (vegetable matter, seeds)
Waste from food processing
Here are some criteria to consider when choosing your fuel source :
Long-term supply and quality of fuel (uniformity, thermal value, ash content and moisture percentage, etc.)
Consider the current price and its variations for the future as well as the price of the equipment needed for this type of fuel.
Easy to manage on site
Everything related to storage, transportation of fuel to the boiler, the transformation of wood into chips or pellets, etc.
Choose your equipment To make your heating system profitable over the years, it is important not to compromise when choosing equipment. Buying new equipment will be expensive at the time, but will represent an investment that can last more than 20 years! Buying used equipment may be less expensive at the time, but it won't last as long and may cause surprise expenses over the years.
Also, make sure before you buy that your equipment is powerful enough to fully heat the space required. To evaluate the power of your unit, look at the British Thermal Units (BTUs). Boiler manufacturers can help you with this. An engineer specializing in biomass, heating systems or building heating will be your best resource! For boiler manufacturers or engineering references, don't hesitate to contact us.
Here are some relevant factors to consider when choosing and managing your storage space :
Size of the building
Your storage facility needs to be large; your biomass fuel can quickly become cumbersome. Calculate your needs based on the amount of energy required as well as the frequency of the supply.
Ideally, the storage building should be located near the boiler room to facilitate the transfer of fuel to the combustion vessel. The building should also provide easy access for delivery vehicles in all weather conditions. An efficient storage system will allow you to identify older fuel for use first. If you are using wood, I recommend that you save your best wood for the fall/winter seasons and use wet or deteriorating wood for the summer.
Moisture, especially in the wood, will be your worst enemy, so don't leave your biomass in the open air. It will be important that the storage place can protect from rain, wet soil and ensure that the wood can dry without accumulating moisture.
For storage safety, limit pile heights to less than 8 m and pile sizes to less than 1000 m3/tas. It is important to provide easy access for emergency vehicles at all times.
Find a way to dispose of or use the ash.
Ash remaining in the combustion chamber can be disposed of in a landfill or added as an amendment to the soil to improve its agricultural quality. Fly ash may be considered hazardous and should be disposed of with a filter. Simple as that!
LET'S COMPARE THE 2 EQUIPMENTS
I had the pleasure of interviewing two Orisha customers: Jaymie Thurler of Rutabaga Ranch (Ontario) and Frédéric Tremblay of Les Jardins d'Élisabeth (Quebec)! Jaymie has a log biomass boiler while Frédéric has a chip biomass boiler. They told me about their experience with this type of installation, the positive and negative aspects, the costs involved and much more! I leave you the pleasure of discovering their testimonies in parts 2 and 3 of this blog post on biomass.
Although similar, the wood log biomass boiler and the wood chip biomass boiler each have their particularities. The main difference between the two systems lies in their modulation capacity. The log boiler allows reducing the oxygen supply to the already-filled combustion chamber. The wood chip boiler allows to stop the addition of fuel: this avoids polluting combustion phases in the absence of heating demand.
Description of the equipment
Wood chip biomass boiler
The time invested in processing biomass (processing the wood cord VS chipping the wood) is less in the case of chips.
It is a precision instrument: measurement of quantity poured, measurement of the quantity of fuel not burned, automatic fuel pouring system, etc.
The chip system allows optimized use of the fuel. However, it is important to have a chip with low moisture content and a grain size that meets the specifications of the boiler manufacturer. In short, the fuel must be of good quality, unlike the log boiler which is less capricious in terms of fuel.
Storage structure and loading using a screw: that means less physical effort and time spent! The cycle can be programmed in advance according to the heating needs.
Biomass boiler with wood logs
Operates with less precision than the wood chip biomass boiler.
Less fickle about the type of biomass used as fuel!
Provides slow and efficient combustion
Regular and manual loading: this means time and physical energy dedicated to the task.
Just before concluding, I would like to specify that heating your greenhouse is an excellent approach, but does not guarantee the superior quality of your crops! To optimize your production, it is not enough to heat, but to control the climate inside your greenhouse. Each plant requires specific conditions to grow at its best, but it is not always easy to manage this climate control or to acquire the necessary expertise to do it without help. Automation is a solution to this problem. If you have any questions about automation, don't hesitate to contact our team!
I hope this blog post has been able to enlighten you, dear reader. Don't despair! This blog article is only part 1 of 3. In the next 2 parts, you will find Jaymie's and Frédéric's testimonials. They will tell you about their experience with their biomass boiler.
While waiting to see you in the next blog post, you can write to me by email or via our social media Facebook, Instagram and LinkedIn to share your opinion, your experience, your ideas for articles you would like to read or simply to tell me about your day if you feel like chatting! Rest well, and take care of yourself and those around you.
Take care of yourself and those around you!