Understanding Solar Collectors
Hello everyone, today we are going to look at solar collectors. So what is these solar collectors means? The solar collectors are collecting solar radiation and providing the heat energy. So simply we can say the solar collectors are transforming the solar radiation into heat energy. So this is the the solar collectors is look like. So I didn't see these uh solar collectors in uh in Sri Lanka and I have seen these solar collectors in Australia and uh some other countries. So reason why we in Sri Lanka we are not using much of hot water for our daily consumption, daily purpose, so the solar collectors are not famous in Sri Lanka because of this reason. But if industries they want to uh have a hot water for some processing needs, they may recommend to install the solar collectors. I mean it's recommended to install the solar collectors rather than installing the solar panels.
Solar Collectors vs. Solar PV Panels
First thing we have to understand that what is a difference between the solar PV photovoltaic panels and the solar collectors. We have been studying about solar panels for last 6 months. So solar photovoltaic panels uh we know already that it convert the solar radiation into direct electricity. I mean is a is a way of producing the direct electricity. So is a simply is a way of producing the electricity. But solar collector is only produce thermal energy. We don't produce electricity. We just produce thermal energy. In other words, we are storing the thermal energy which is available in the sun. Sun is emitting radiation, so it's already is hot. The the the energy is available. We we collecting that energy, the thermal energy and store it in the water or any other liquid, anything. So it's simply the beauty of solar collector is, there's no the conversion losses in in solar panels. So there are a lot of um energy losses when uh generating electricity. Then we have to transform DC current into AC current. Then we have to use it in our house.
Why Use Solar Collectors?
Simple you can imagine that uh you want to get a hot water. So what you're doing? You are using the the water heater, hot water heater. In in my house we have a hot water heaters. So we uh pluck in into the electric electric uh uh supply and uh get the water heater um get heated. So what are the energy conversion here? We are generating electricity from solar panels. Then the solar panels electricity DC current has to be converted into AC current through the inverter. Then the current coming to our house. So the wiring losses and the conversion losses and the efficiency losses all included. At the end we are getting the hot water. So rather than doing this, but the the recommended way is to install the solar collector. So solar collector directly can heat your water. Simply, solar collectors directly can heat your water without creating or generating electricity. So there is no process of generating electricity, just the process of heating the water. So the the the use of solar collectors provide alternative for traditional domestic water heating. So this a simple purpose is to domestic hot water heating.
Types and Applications of Solar Collectors
As I said earlier, in Asian houses and Sri Lanka and Indian houses we don't use much of the water heating because we are in the hot country, hot weather uh country. But the people who are living in the cold weather, London, Canada, and some season in Australia, they need a hot water and they the the heating of the the environment like the room heating. So those uh purpose they using the solar collectors.
Overview of Collector Types
So so what are the types of solar collectors? The flat plate collectors, there are four types. So first one is flat plate collectors, evacuated tube collectors, line focus collectors, and point focus collectors. We'll look at one by one. Uh first we will look at one then the next video we will look at the others in a separate videos. So first is the first one is a flat plate collectors.
Flat Plate Collector Design
So the collectors are simply metal boxes that have transparent glazing as a cover on top of the dark colored absorber plate, usually copper or aluminium is a good conductor. So what is happening here? We simply we are sending the cold water here and we're getting the hot water from the collector. This is a flat plate collector. What is happening? This is a pipe here, the like a water the pipes. But the the beauty is here, there's a glass plate. So there's a glass plate that's covering all these internal tubes. So these are the internal tubes passing the water or you can use a liquid or anything to heat up. So this the plate is covering this. So this this uh entire structure within this uh uh glass plate, so covered with a insulated minimum. So the bottom of the side is covered with the insulators because we don't want to uh release the heat to atmosphere. So the idea is that the the glass plate going to absorb the heat, whatever possible it can absorb the heat solar radiation through the solar radiation and pass it to these tubes. These are the tubes. Then these tubes will generate the hot water. So this is the idea.
Key Components and Operation
So so if you go deeper into the the the structure of uh the uh this appliance of uh water flat plate collectors, it has a transparent screen, that's a glass screen usually, usually is a glass screen. So transparent green so that's because it has to absorb the solar radiation. That's why we have this transparent screen. Then the black absorber. This is the absorber. There's a plate we keep here to absorb all the heat. It has to there a black plate, the black color because it absorb more heat. So absorb all the heat and transform into the fluid tubes. These are the tubes. This is a the front view of the tubes. So this is the uh fluid tubes, fluid or water. So so this uh black absorber, this black absorber transfer all the collected heat energy, thermal energy into the water passing through these tubes. Then the water get heated. So we got the hot water. So the output is a hot water.
Main Components of a Flat Plate Collector
The main components are the transparent cover, the glass, and absorber plates, that's a black color, the absorber plate, and the tube carrying heat fluid. These are the tubes and these are the tubes carrying the fluid, and insulated. The bottom we have to have insulation because otherwise the heat will remove from the bottom of the tube. So we don't want the heat heat to come out like this. So we put the the insulation, thermal insulation in the bottom side of the the setup, we can say setup or the appliances. Okay, then the casing. This is an casing. So this is the structure of the flat plate collector.
Practical Applications
This is another good picture, the very nice picture. So um solar collectors collect, capture solar energy and uses that energy to heat water in the home for bathing, washing, heating, can even use for heat outdoor swimming pools. So that's why we said like in um is mostly used in developed countries like Australia, Canada, London because they using the uh hot water for bathing, they use hot water bath, washing, they use a hot water and they need a heating of uh the house. Heating of the house is important for during the winter season. So that's why the flat plate collectors are very famous. However, for Sri Lankan context or Asian context it is applicable for many industries where they use hot water for many processes. Some food industries, factories, the many industries they using hot water. And here, if you look at here, this is a cold water in. They have the pipe, the big pipe it has a water cold water in. Then it's connected, the pipe is connected here. And at the end another pipe is there, it's kind of setup we can have a different way of setup. And this uh pipe uh collect all the hot water coming from all each pipes, tubes or pipe of tubes and bring it a hot water out. So this is a and the glass screen, the glass screen is kind of glass material. And the back sides uh absorb a plate and the insulations, everything is insulations in the back sides, in the bottom with insulation and here absorber plates. So all these elements are there.
So uh that's all for today. So the application point of view, hot water, the the the solar collector is used to produce hot water, used to produce heat, used to store heat. So wherever you need, simple in simple way if you want to install wherever you need hot water for your process instead of having the solar panels, you can have a solar collectors because solar collectors directly uh make the uh make the hot water or produce thermal energy. Thank you very much. Please subscribe this channel and continue support.
Flat Plate Solar Collector | Technical Specifications
| Feature | Detail |
|---|---|
| Primary Function | Collect solar radiation and transform it into thermal energy (heat). |
| Energy Output | Thermal energy (hot water, heat); no electricity generation. |
| Transparent Cover | Usually glass screen; absorbs solar radiation and passes it to tubes. |
| Absorber Plate | Dark colored (black), typically copper or aluminium (good conductor); absorbs heat from solar radiation. |
| Fluid Tubes | Internal tubes (pipes) carrying water or other liquid; fluid is heated by absorber plate. |
| Insulation | Located at the bottom and sides; prevents heat loss to the atmosphere. |
| Casing | Metal box enclosing all internal components. |
| Typical Use | Domestic hot water heating, room heating, industrial process heat, swimming pool heating. |
| Efficiency | No conversion losses (electrical to thermal) compared to solar PV + water heater systems. |
Frequently Asked Questions
What is the primary function of a solar collector?
Solar collectors collect solar radiation and provide heat energy, transforming solar radiation into thermal energy. They are designed to heat water or other fluids without generating electricity.
How do solar collectors differ from solar photovoltaic (PV) panels?
Solar PV panels convert solar radiation into direct electricity, which can then be used or converted to AC for household use. In contrast, solar collectors only produce thermal energy (heat) and do not generate electricity. Their main purpose is to heat water or other liquids directly.
What are the main components of a flat plate solar collector?
The main components of a flat plate solar collector include a transparent cover (usually glass) to absorb solar radiation, a dark-colored absorber plate (often copper or aluminum) to efficiently capture heat, fluid tubes that carry water or a liquid to be heated, insulation at the bottom and sides to prevent heat loss, and an outer casing that encloses all these components.