HOW TO HEAT A GREENHOUSE WITH SOLAR PANELS ?

Exploiting natural resources to make industrial processes more ecological is the flag of agricultural technology these days. At the moment, solar panels are not among those devices which are unrelated to greenhouses or crop fields. Solar power is used to create clean energy to heat a greenhouse. Besides heating solar panels are also used to power automatic irrigation systems, lighting, or anything else that is powered by 110V or 220V. Believe it or not, the world is slowly changing to become a better place! If you want to be part of the change, stay with us, and learn how to heat a greenhouse with solar panels.

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Greenhouses are useful, but not magical

Have you ever wondered what happens to a plant when it does not get enough sunlight and heating? The answer seems too obvious to even ask. Since we were children, we have been taught that plants, without any lighting or heating, die because they cannot perform photosynthesis, they are not capable of producing ATP. In simple words, they are not able to create cellular food that keeps them healthy and strong. But what would you think if I told you that plants do not necessarily have to be exposed to the sun to grow? Hold it right there… You have now my attention.

To begin with, let’s talk about the role of greenhouses: what will it be like to live in a world that is entirely adapted to your needs? A world where it is as cold, hot, or humid as you need to grow up healthy and strong. Luckily for some plants and animals, that is not as far from the truth. At least for a tomato or paprika, that fantastic world has a name: greenhouse.

Greenhouses are enclosed spaces that meet special conditions to ensure that plants grow and bear fruit regardless of the season. For decades, greenhouses have been the most incredible and simple agricultural invention. They keep food protected from extreme temperatures and environmental conditions that are too hostile to them. However, greenhouses are not magic. The potential for uncontrolled greenhouse decreases when there is not enough sunlight or when the winter season arrives. Fortunately, for both greenhouses and plants, technology is advancing, and today it is possible to take natural resources and store them for later use. In a word ( two actually), solar panels.

How do solar panels work?

Although it seems like an innocent question, the answer can be a bit complicated. Today, there are different types of technology applied to solar panels, and each of them works differently. However, we will concentrate on explaining how solar panel technology applied to greenhouses works. In other words, photovoltaic technology.

Solar panels are systems capable of converting solar energy into electric current, capturing it through photovoltaic cells. Contrary to what many believe, they do not need a beautiful radiant sun to produce energy. A set of solar panels can produce electricity even on cloudy days, as it does not require direct sunlight.

Let’s see how this process works, step by step. The first step is the most obvious: sunlight falls on the panels and produces direct current electricity. This direct current travels wild and uncontrolled through a wiring system to an inverter, which transforms it into alternating current. That is to say, the one that moves everyday devices such as hair dryers or charges the battery of your mobile phone.

This system is very similar to the one used by electricity companies to bring electricity to homes and businesses, but… it is totally free! Or at least, for now. We are still waiting for the fees you are surely willing to pay for the sunlight.

There are several companies that even pay solar panel users to use the surplus electricity they produce.

That certainly sounds good, doesn’t it?

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Can they be used in greenhouses?

Well, that all sounds pretty interesting, but what does it have to do with greenhouses and crops? Very much, actually. Greenhouses are great for conserving the heat and warming the environment, but if you want to keep your production of, for example, tomatoes all year round… a simple greenhouse is not going to be enough.

Until a few years ago, agricultural companies used to use oil-fired boilers to produce energy. However, today’s high oil costs and their effects on the environment have forced these companies to use other alternatives. Currently, many universities and agricultural companies are beginning to change the type of electricity they use to cause less environmental impact and conserve the beautiful blue planet we live on. An incredible example is NEIKER-Tecnalia.

NEIKER is a public institution of the Basque Autonomous Community, Spain. It focuses on research and innovation projects that seek to incorporate technology into agriculture to make it more efficient, clean, and environmentally friendly. Since 2009, they have been working on a system that incorporates solar energy to power their greenhouses.

In one of their experimental farms, located in Redio, they work on an unusual and incredible project: they grow tomatoes all year round, using only solar energy. According to Patrick Rigar, the project director, if this type of energy were not available, it could only be cultivated during the months between May and October. An unproductive period of time, compared to all that could be cultivated over the course of a whole year!

To heat a greenhouse, they use energy from solar panels. In this experimental greenhouse, worthy of any mad scientist, researchers are constantly testing to find the best way to keep plants warmed up.

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Basically, they work with two modalities. The first is to heat only the roots of the plants so that a good amount of energy is saved, but the overall temperature of the greenhouse is not maintained the same way. On the other hand, they also work heating the greenhouse as a whole, but at the expense of consuming even more electricity.

Setting up a 250 Watt Solar Panel based Heating System

Here is a simple Example on How you can heat your Greenhouse:

The video should give you a clear understanding of how to setup up a greenhouse heater using solar panels. The most important thing that you need to consider is the size of the heating system that you install in your greenhouse. For a small greenhouse (8×8 feet) a 250-450 watt electric heater would do the job. I think for most of the people 250-watt heater will do just fine. If you need the exact wattage for your greenhouse, you can ask us by posting a question in our Forum.

Things that you will need for setting up your solar panels powered greenhouse heater:

Solar Panel Kit:

You will need to buy a solar panel kit, if you are planning to build 250-watt solar heater (which works best for most of the people), you should buy 500 Watt solar panel kit. I highly recommend the ACOPOWER Solar kit (See its current price), this is one of the best deals you can find on Amazon.

This kit uses an MPPT controller, which is efficient than the PWM controller and it also provides cables and connectors for connecting the solar panels to the charge controller. They have provided a diagram that you can follow to connect the solar panels to the charge controller.

Heater Options:

For heaters, you have two options. 1) Use 12 volt DC heater and connect it directly to the charge controller. 2) First, convert 12 volt DC into 110 volts AC and connect it to the AC heater. Both of these options have benefits and drawbacks. Let’s discuss them in detail.

12 Volt DC Heaters:

You can directly connect a 12-volt heater to the charge controller without buying anything else. However, there is a limited number of DC heater and a lot of users have problems with commercial DC heaters. RoadPro RPSL-681 is considered to be one of the best DC Heater, however, this heater has low user appreciation.

You can always build a DIY heater for your greenhouse. There are a large of tutorials on YouTube for building a 12 DC Heater.

110 Volt AC Heaters:

An alternative option is to use a 250 watt AC Heater and connect it to the charge controller through a DC to AC inverter. If you choose this option you will also be able to use other 110 Volt appliances like AC Fans, Bulbs, etc in your greenhouse.

You can by Brightown 250 Watts heater and connect it to BESTEK 500W Power Inverter DC. The input of the inverter should be connected to the output of the charge controller.

I personally, like this option because you can not only use the power for heating but you can also use it for lighting and ventilation as most of the light and appliances are AC compatible.

Batteries Backup:

You can use 100 Ah Lead Acid battery (I recommend using Universal Power Sealed Lead Acid Battery ). One 100 Ah, 12-volt battery (it is equal to 1200 watt-hour) will give you a backup of 4.8 hours if you run 250-watt heater. You can add more batteries in parallel and increase the backup time for your solar panels based heating system.

Important Notes:

If you decide to expand the system in the future by adding more panels, you will have to replace the charge controller to a bigger one that can support the required current. You can always post a question in on our Forum and we will be there to guide you.

For a greener, more beautiful and happier world

If there is one thing that all human beings agree on, it is that we want to preserve this beautiful planet for a long, long time. And to this end, it is time to stop using technology at the service of destruction and turn it into a vehicle for creating, preserving, and diversifying.

Are you interested in this topic?

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We want to know how passionate you are about agriculture, leave us a comment and share with us what you know about solar energy and its use in greenhouses! Ask questions, let’s debate! This is how we will continue enriching this article every day.

 

28 thoughts on “HOW TO HEAT A GREENHOUSE WITH SOLAR PANELS ?”

    • Based on your greenhouse specs. A 1000 watt solar panel array would do a perfect job. But keep this in mind that during the day the sun will almost do the job for you. You have to store this energy and heat your greenhouse during the night.

      Reply
      • Hello, I am building a 6×6 greenhouse in Wisconsin. Where the average winter temperature is ~7F plus or minus 5F, that is -13C plus or minus 3C, from January to February.

        What size heater should I get. I also have two 100 watt solar panels, would that be enough?

        Reply
        • I think 2 panels with 100 watts will do the job of heating for your greenhouse during the day. However, during the night you must have a backup heating plan for your greenhouse. Furthermore, I would recommend using good insulation for your greenhouse. if these conditions are satisfied a 200-400 watt heater will do the job for you.

          Reply
  1. I have a greenhouse in the arctic and would like to know more about how to heat economically. Tonight it will be 3-C and it is only July 9th so I am in need of information as soon as possible.

    Reply
    • 1. Add Compost in your greenhouse. It will keep on decomposing and will also heat your greenhouse.
      2. Add water drums in your greenhouse at the back wall. Paint it black. it will absorb sun energy and radiate it during the night.
      3. Use solar panels to heat the greenhouse during the day.
      4. If you can store the solar energy in batteries then it would be great. You can heat your greenhouse during the night as well.
      5. If you want to save more energy. You can dig the floor of your greenhouse. Add large spacious rocks at the bottom. and install segereage tubing going into one end of the greenhouse and coming out from the other end, Blow air from one end using a fan. During the day the rocks underneat will heat up and during the night the will radiate energy. So the temperature of your greenhouse would almost remain constant.

      Reply
  2. I’ve got a 14 X 24 foot greenhouse and want to at the very least run all my lights, misters and heat mats with solar. In the future perhaps I can augment the propane heater with solar energy. I’ve also got the perfect set-up for solar panels. The greenhouse was constructed on the south side of a detached garage, so the roof faces south. I am a solar rookie and would love to get advice on just about everything pertaining to harnessing solar energy!

    Reply
    • Wow. You have a large greenhouse. You can definitely shift all of the functionality on to solar energy. Solor energy has no running cost. But there is one problem. It requires alot of batteries to save this solar energy. and as you know batteries are costly

      Reply
    • Yeah, I was a little busy. For 8×10 greenhouse 600 watts are enough. So Just buy 2 solar pannel with 12 volt DC Heater. If you cannot find a 12 volt heater. Buy an inverted and Buy an AC heater which is very common. You can find all of these things in your local market. or you can also buy it from Amazon

      Reply
    • 1. You have to heat your greenhouse.
      2. You have to add Led Grow lights, to extend your lighting time.

      1.1 You can Add Compost in your greenhouse. It will keep on decomposing and will also heat your greenhouse.
      1.2. Add water drums in your greenhouse at the back wall. Paint it black. it will absorb sun energy and radiate it during the night.
      1.3. Use solar panels to heat the greenhouse during the day.
      1.4. If you can store the solar energy in batteries then it would be great. You can heat your greenhouse during the night as well.
      1.5. If you want to save more energy. You can dig the floor of your greenhouse. Add large spacious rocks at the bottom. and install segereage tubing going into one end of the greenhouse and coming out from the other end, Blow air from one end using a fan. During the day the rocks underneat will heat up and during the night the will radiate energy. So the temperature of your greenhouse would almost remain constant.

      2.1 Provide almost 10 hours lighting. If during the winter the sunlight is just for 6 hours. Then provide your plants with 4 hours of artificial lighting.

      Reply
  3. yes, I very much want to learn how to heat my 2 greenhouses with solar panels so I can supply crops year around such as potatoes, cabbage, broccoli, turnips, and other cold-weather foods.

    Reply
  4. Greetings!

    Your article was very inspiring. I am looking at building 4 greenhouses at 33’x13’x7.5′. What kind of system would I need to get these powered up to grow hemp? Its season on in NJ. I am looking into the compose. How can we get that started? The rocks, how big of rocks should we put underneath? Its like a geotherm system? very interesting and will save alot of the electricity by providing more heat in the winter time.

    Reply
  5. Good day

    I want to have a greenhouse of about 3 Hectares with solar grids/Panels. What size of Solar panels do I need and approximatry how much will it coast me. please advice . Thank you so much for the beautiful article it was indeed helpful.

    Reply
    • 3 Hectares is a huge space and I will not recommend installing solar panels for such a greenhouse because it will cost you way much. You should install solar panels only if you have automated vents, or for lighting etc. You should use a Solar Air heater and ground air heat transfer system (GAHT) system for heating your greenhouse. You can always join our forum and ask questions there.

      Reply
  6. Good day
    Where and how do i get the solar panel system for growing my Canabis in South Africa during this winter time as we want plough all year round?
    Thank you.

    Reply
    • On large scale using a solar panel for heating your greenhouse is not a great way to go because it will cost you loads and loads of money. I would highly encourage you to take your time and provide your greenhouse with perfect insulation. PLz, search GHAT systems, Heat mass, Heating a greenhouse for free. YOu will get cool ideas that will help you lower your heating costs.

      Reply

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