Solar energy has been dominating almost every conversation that we are having lately. It does not matter if we are sitting with family, friends, or colleagues because, at one point or another, solar power ends up becoming the topic of conversation. People did not know much about solar energy 10-20 years ago compared to now. Chances are that we probably already know someone that has solar panels installed in their home or building.
These are good conversations to be having because we need to have them. The planet is slowly dying, and switching over to clean, renewable energy sources like the sun can help save it. The sunlight that reaches us makes it possible for us to live and sustain light, and the energy coming from the sun at a single time is more than enough to meet the planet’s energy needs.
Of course, a lot of people tend to think that solar energy is only harnessed via solar panels, which is not entirely true. There are many different methods to harness solar power, and if you are interested in learning more about them, you can keep on reading below.
Some of the most evident technology includes photovoltaic technology, synthetic photosynthesis, solar thermal energy, solar buildings, and solar heating systems.
Active Solar vs. Passive Solar
All solar technology falls into two main categories, which are active solar and passive solar technology. The difference between the two lies in the process of harnessing, distributing, and converting to solar energy.
Photovoltaic and solar water heating methods that are used to collect solar energy fall into the category of solar techniques.
On the other hand things like placing a building’s position to get maximum sunlight yield, selecting materials that contribute and improve thermal mass, etc. fall into the category of passive solar power.
There are advantages the entire planet can make use of like the fact that carbon emissions will decrease globally, which means decelerating the rate of global warming, less worry about price fluctuations, and always having an abundant source of clean, free energy. This is something everyone can take advantage of being it a developed country, or an underdeveloped third world country, and so on.
Nuclear Fusion And The Sun
If you think about it, the sun is primarily a nuclear reactor as well, and all kinds of things are going on on the surface and the depth of the sun. Nuclear fusion happens to be one of the many processes that are predominantly happening in the sun.
The extremely hot temperature of the sun leads to hydrogen atoms breaking their bonds and coming apart, and then the nuclei of the hydrogen atoms fuse. As this goes on, there comes a point where four nuclei will end up fusing, and this leads to the development of a helium atom. As this is happening, some matter will be lost, and this loss of matter will end up releasing into space in the form of bright, radiant energy.
Only a small chunk of the sun’s energy reaches the planet, and that small amount of energy is more than enough to power the entire planet at once. Given how the sun is a source of free, unlimited energy, there is a lot that it can do for us right now and in the future. There is a lot of research being done in the field of solar power, and scientists and innovators are trying their best to make solar energy accessible and affordable for as many of us as they can.
A Look at Solar Collectors
As the name suggests, solar collectors will harness sunlight and then store it so that it can be used later. Of course, this is where things get a little complicated because a lot of people think that the sun reaches everywhere evenly, and that is not the case. The sun is not able to distribute energy evenly, and this is why some cities, countries, or geographical areas get more sunlight than others. Many things like the time, the weather, the latitude, the number of clouds present, etc. all play a role in the amount of sunlight being present in an area.
This is where solar collectors come in. You can find solar collectors in everything, like the seat covers or windows of a car if the car is left in sunlight. In this scenario the solar energy that is collected becomes heat, and this is why the car ends up heating up on the inside.
Of course, this is a pretty basic example, but a solar collector should have the following features:
- The solar collector has to be able to absorb sunlight.
- Sunlight should be able to pass through the collector.
- Any heat that is produced during the process should not escape.
- All sunlight that is collected needs to be converted into heat.
Since we are still on the subject of solar power, it is pretty evident that solar water heaters harness sunlight to heat water. Houses that happen to fall in lower topographical latitudes can take advantage of solar heating systems. There are primarily two main types of solar water heaters, and these are evacuated tube collectors, and glazed flat plate collectors.
The unglazed plastic variant is used for heating larger bodies of water like swimming pools. Currently, different countries are planning on increasing their solar water heater’s capacity, and countries like Cyprus and Israel are responsible for overusing these systems to meet 90% of their domestic water heating needs.
An Alternative For Heating And Cooling Systems
If we talk about the US, then commercial buildings alone consume up to 30% of the energy that is produced.
Energy consumption when it comes to both commercial and residential buildings are mostly because of heating, cooling, and ventilation systems. If we harness and use solar energy here, we can make a huge difference in the amount of non-renewable energy that we need. This is where we start talking about thermal mass as an alternative collector.
Thermal mass is actually not a new concept, and you will find that this was being used hundreds of years ago as well, and would be used to capture solar energy during the day and then subsequently emitted at night time. Some very common examples of thermal mass include cement, water, and stone.
Many factors can come into play when it comes to the performance of thermal masses like the choice of material, the size of the material, the amount of available sunlight, the weather, and so on. When thermal masses are placed and used correctly they can help to maintain and sustain the temperature of the space, and reduce the need for any other chilling or heating equipment.
A good example of using thermal mass in cold regions is through the use of a thermal chimney, which is a passive solar system that involves a long vertical tube that connects the external and internal surfaces of the building. When the chimney starts heating up, the air that is already present in the chimney starts becoming warmer, which leads to an updraft that will end up taking the air in the entire building.
Can Greenery Help?
Our choice of trees and plants can also end up improving the efficiency of our solar-powered heating and cooling systems. Where you plant your trees around and in a building can make a lot of difference. For instance, when placed correctly, the leaves can act as a natural shade during hot and summery weather. Similarly, they can also allow light to pass through during colder weather.
When thinking of planting trees, you need to think of tree type and its placement along the equator. For example, you cannot place deciduous trees on the area of the building that is facing the equator because they will end up affecting solar accessibility during the winters. What you need to do instead with these trees is place them on either the west and/or the east side of your building because they will be able to provide shade during the summer and at the same time, will not disrupt solar access as much during the cooler months.
Solar-powered cooking is not a new thing, and in fact, the oldest form of a solar cooker was constructed back in 1767 and was better known as a box cooker. Its setup involved two things, and that was a transparent cover and an insulated bowl. Box cookers worked well with cloudy weather, and could also perform between 90-150oC.
Another method of solar cooking involves panel cookers. The setup of a panel cooker involves an insulated bottle and a reflective panel, and this setup can reach up to the same temperature as a box cooker.
Lastly, another type of solar cooker that can be used is reflector cookers. A reflector cooker is slightly more complicated in terms of setup since it involves the use of different concentrating geometries to direct light on the cooking panel. These types of solar cookers need to be positioned according to the direction of the sun but can go up to a temperature of 315OC.
Thermal Energy Storage/ Molten Salt Technology
These two terms are used interchangeably because the process is the same for both; which is when thermal power is collected by the towers in a solar power plant. Molten Salt Technology can be used to create electricity during bad weather and at night as well, and this can be effectively used throughout the year as well.
Molten salt comprises a mixture of calcium nitrate, sodium nitrate, and potassium nitrate, forming a non-toxic mixture that is also fireproof.
Molten salt is already used as a heat transportation fluid for biochemical industries and metal-related businesses and industries as well.
As the mixture heats up, it remains fluid and can be moved to a hot storage container. This container can end up storing this thermal energy for up to a week. Super-heated steam generation is then done by taking the hot salt from the storage container and passing it through a steam generator, and this steam can then be used to power different plants like nuclear, coal, and oil plants.
Solar Power For Electricity Production
The process of converting sunlight into electricity is solar power. Now when it comes to converting sunlight, you can either do it indirectly through concentrated solar energy, or you can do it directly through the use of photovoltaic technology.
The concentrated solar power system involves the use of glass and a tracing system to collect and then concentrate a large sunlight area into a small beam.
Photovoltaic, on the other hand, involves the use of the photoelectric effect to convert sunlight into electricity.
It is believed that both CSP and photovoltaic use will increase over the years, and is estimated to increase up to 11% and 16% respectively. This is still a little newer than photovoltaic cells and can be traced back to the 1980s.
Photovoltaic is the recommended way to go, especially for residential buildings. As we mentioned before, the process involves the use of the photoelectric effect to convert sunlight into electricity. A lot of people do not know this but the first solar cells were made in the 1880s by a man named C.Fritts. This design was later improved on by a German engineer in 1931 where he ended up replacing copper oxide with silver selenide instead. In 1954, Daryl and Calvin improved solar cells further by using crystalline silicon.
Earlier on the efficiency of crystalline silicon was just 4-6%, however, thanks to modern innovation and research, we have now managed to bring it up to 40%.
When it comes to storing solar energy, it can be made possible via a good thermal mass system. We mentioned this already, but the most obvious choice of materials for thermal mass includes stone, water, and earth. When designed correctly, a thermal solar system can limit our heating and cooling needs significantly.
Two other materials that are also used for thermal storage systems are Glauber’s salt and paraffin wax, both of which are readily available and cheap materials.
Salts in general can store a large capacity of heat, can be used for residential heat storage needs, and is compatible with conservative power structures as well.
There is still a lot that is being done in the field of solar energy, and things will only get better with time. Solar panels are one of the best investments that you can make, so you should consider them, and even if you are not able to afford solar panels at this time, you can still opt for smaller solar-powered equipment like cookers, lights, and so on. These small things can become your inauguration into solar energy, and you can then decide where you want to go from there.