The weather can sometimes be unpredictable and even when you can predict the weather; you can’t always have the right weather suitable for your crops. To help counter this problem, a greenhouse was invented in the early years. A greenhouse is an enclosed structure with walls and roof made out of transparent material like glass. In this structure, plants that need regulated weather condition are grown. Greenhouses are mostly used to regulate light, warmth and air to suit your exotic plants.
Heating of greenhouses can be very expensive because the regulation of heat and light can consume a great deal of power. One way to heat up your greenhouse is by using solar energy. We will be writing about how to heat a greenhouse with solar panels in this article and we are sure that you will learn a great deal from it.
Types Of Solar Panels For Greenhouses
There are different types of solar panels that can be used for greenhouses and each of them has their benefits. In the subsequent paragraphs, we will be writing about them.
Monocrystalline Solar Panels
The monocrystalline solar panel is made from a material called the single crystalline silicon. These panels are unique and this is because of their dull, dark colour and cylinder-like shape. With an efficiency level of 15% to 20%, these panels are the most efficient type of solar panels which means that you will be saving a lot of money by investing in these types. Also, their efficiency also means that you do not need a large space for you to have the required amount of energy for your greenhouse.
Another advantage of the monocrystalline solar panel is that they last very long. This is evident due to the fact that most manufacturers place a 25-year warranty on them. This means that after a single purchase, you won’t have to worry about buying another for a long time. Finally, they are ideal for cloudy areas as they can convert any ray of sunshine into energy fast. So, if you are thinking of how to heat a greenhouse with solar panels, then you should consider a monocrystalline solar panel.
As you know, there will always be a downside to most appliances and the disadvantages of the monocrystalline solar cells are listed below:
- They are very expensive and not everyone will be able to afford them.
- The silicon material is usually wasted when cutting during manufacturing. This is probably the reason why it is so expensive.
- The solar cells’ performance drops as the temperature increase. Although, this is insignificant compared to the loss other solar panels suffer.
Polycrystalline Solar Panel
Polycrystalline cells are different from monocrystalline cells in so many ways and some of which include the fact that it does not need its sides cut out. The silicon of the panels is melted in order to form square shapes which means that there is less loss of silicon during production. In addition, the efficiency of these panels is around 13% to 16% which means that they are not as efficient as their monocrystalline counterpart. The polycrystalline solar panels also work better in hotter temperature which makes it a good option for those living in hotter climates.
Some of the disadvantages of the polycrystalline solar panel include:
- It is not as efficient as the monocrystalline solar panels
- It requires a large amount of space due to its lower output rate. With these solar panels, you will have to buy more to get your desired energy output.
Thin Film Solar Panels
The thin film solar cells are manufactured by adding lots of thin layers of photovoltaic cells together to place one single module. The thin film solar panels differ according to the materials used in bringing them together. Generally, there are 4 types of materials that can be used and they are; Amorphous silicon, organic PV cells, copper indium and cadmium telluride. The efficiency rate for the thin film solar panels is between 7% to 12%. This is quite low compared to other types of solar panels but scientists/researchers are already working on getting their efficiency by up to 16%.
Benefits Of Using Solar Panels To Heat Up Your Greenhouse
Thinking of what you stand to gain from learning how to heat a greenhouse with solar panels? Then you need to read the points highlighted below.
Absence Of Toxic Emissions
One of the most important benefits of using solar panels to heat up your greenhouse is that you are making use of pure energy. With solar energy, you are assured that there are no toxic gasses which can affect the growth of the plant being emitted by the power source. With this, you are not just protecting your plants but also the planet too.
Effective Temperature Control System
Other sources of energy might need an additional temperature control system to enable the plants in the greenhouse to thrive. Using solar panels to generate heat for the greenhouse, on the other hand, gives you a choice to stop the solar panels from heating up the greenhouse. This act can easily be done by adjusting the settings of the solar panel. In addition, you can install solar panels with sensors that can automatically open vents in case of overheating of the greenhouse.
Using solar panels in a greenhouse is cost effective compared to other sources of energy. Whilst the initial setup cost might be expensive, but the cost benefit you will derive from the investment will definitely ensure you get your money’s worth in the long run.
How Solar Powered Greenhouses Differ From Regular Greenhouses
Solar greenhouses are different in different ways and these differences will be highlighted below.
- Solar powered greenhouses make use of heat storing materials which helps it retain the heat derived from solar energy. This feature ensures that the heat generated for the greenhouse is used effectively and efficiently.
- Solar powered greenhouses also make use of a large number of insulation materials to aid the sunshine available for use. This is particularly useful for areas where there is no direct sunlight.
Heat Loss And Heat Transfer In Greenhouses
To get the best crop production result, greenhouses must be heated at all times. A good solar heating system must provide an adequate and uniform temperature for the greenhouse. Also, the heating system must not emit harmful materials which might impede the production of the crops. There are different types of ways to heat the greenhouse but using solar energy remains one of the best ways.
When setting up a solar heating system for greenhouses, you should consider the occurrence of heat loss. Heat loss occurs through different modes of heat transfer which are: convection, conduction and radiation. When these modes are calculated and combined, the heat needed for the greenhouse can be determined. To put this in simple terms, when these 3 factors are considered, you will get an idea of how much heat your greenhouse needs.
Convection Heat Transfer
This can be described as the physical movement of both warm liquid and gas to a cooler environment or area. When heat loss by convection happens in a greenhouse, it is usually through oxygenating or airing. One thing to note is that heat loss through convection is not just about the movement of air but by the movement of water vapour too. Evaporation of water in greenhouses combines to absorb energy which often leads to heat loss or heat transfer.
Radiation Heat Transfer
Radiation heat transfer usually happens between two bodies or materials that are not touching each other. Heat radiation is often reflected, transmitted or absorbed in a straight line. You must understand that all objects release this radiant heat and the heat radiation varies in different objects. To reduce this radiant heat energy, you should surround the target object with a non-transparent barrier. This barrier will ensure that the radiant heat is reflected back to the source of the heat. Also, ensure that the absorption rate of this barrier is low in order to prevent it from heating up too much which might affect other objects outside.
Conduction Heat Transfer
Conduction of heat happens through objects having direct physical contact. How objects conduct heat depends on the area, type and properties of the objects. To reduce heat transfer by conduction, you should insulate the objects that easily conduct heat. This can be done by placing thermal conductors or insulators like rubber and wood on the object.
Glazing Of Greenhouses
When trying to ensure that the heat generated by solar panels for your greenhouse remains in the greenhouse for long, you need to glaze the greenhouse. Glazing involves covering or layering your greenhouse walls and roof with materials like glass, poly film and polycarbonate to keep the heat inside. This is especially important for cold periods like winter or raining season.
Heating up greenhouses with solar panels is very beneficial and apart from the fact that it is cost-effective, you also get to preserve the planet in the process. We also wrote about heat transfer and heat loss. Remember to always consider heat loss when trying to figure out the required heat you need your solar panels to produce. Also, never forget the importance of glazing because of what use is heating up the greenhouse when the heat can be lost easily. Finally, we hope you found this article on how to heat a greenhouse with solar panels helpful. And we are sure you will put all the information in this article to good use.