If you believe that a greenhouse gets warmer because of back
radiation then you are wrong and I will explain to you how greenhouses
really work, they work due to convection and only convection.
The educational establishment, teach greenhouse effect wrong from first principles and it just goes to show how little they and the Carbon Alarmists, whom all do nothing much other than bang on about the devastating effects of Carbon Dioxide actually know. They then go on to claim that global warming, which caused by greenhouse gases is a man-made threat and how this in turn drives devastating climate change which will one day wipe us all out. How many years have they been predicting the end of the world now? I’m actually not sure, it’s been so long.
Greenhouses DO NOT work because of Back Radiation.
This is the sort of backwards drivel which is being taught to students worldwide. You should be aware that this is a non-sense.
The current “completely wrong” consensus theory goes something along the lines like this:-
So, how does a greenhouse actually works when it is present within an atmosphere?
Figures 1.2 How a Green House Actually Works – Convective Currents
Convective Cooling of the Surface, causes warming of the air as it contacts the ground.
You see what actually happens, the air inside a greenhouse is subjected to a powerful convection current. This means that air which is touching the surface of the warmed floor has heat conducted to it from the floor, cooling the floor but warming the air. This causes this bottom layer of air to warm, as it warms, its density decreases because gases expand when they are warmed because they have more energy. This causes the air to rise within the greenhouse and cooler, denser air above it to drop.
Just imagine pouring some oil and dropping a coin into a bottle of water. The dense coin falls to the bottom but the less dense oil, floats on the top, this is what is happening inside the greenhouse. This cooler air drops to be in-contact with the floor, which in turn gets warmed, rises and continues the cycle.
The first lot of air, which was warmed, when it falls back to the surface, is warmer than when it first started the cycle, it is warmed again, but to an even higher temperature than before and it is this process of heat cycling which causes the temperature of the air to rise dramatically within greenhouses.
This convection current helps spread warm air around the greenhouse and transfers heat to all the objects within the room, including the external surfaces, these external surfaces prevent the air from escaping the greenhouse.
If there was no roof to the greenhouse, the warm gases would escape and the greenhouse would rapidly cool-down, in fact this is a known method of cooling a greenhouse, you just open up the vents and feel the temperature drop.
This process is also occurring outside the greenhouse, however, outside the greenhouse there is no barrier preventing the air from rising, so the air rises miles high and so cools much more before it comes back down again. Inside the greenhouse however, the air only rises a short way, before cycling back down. This is why the air inside the greenhouse is much warmer than the air outside a greenhouse.
So to summate:-
Greenhouses work because of trapped Convection currents not trapped radiation.
I hope this helps put you on the right path and helps you start to see how you may have been misled, by the left leaning educational establishment, if they have failed to educate on how greenhouses actually work. I believe they do this to disempower people.
My next Illumination, will show how it is a complete nonsense, from a mechanical thermodynamic radiation point of view, to think a greenhouse would cause radiation warming. I will show, how a plate in space is warmer, when compared to a plate in space with a greenhouse on it (with no air), which is cooler and I will explain why that is.
Source
The educational establishment, teach greenhouse effect wrong from first principles and it just goes to show how little they and the Carbon Alarmists, whom all do nothing much other than bang on about the devastating effects of Carbon Dioxide actually know. They then go on to claim that global warming, which caused by greenhouse gases is a man-made threat and how this in turn drives devastating climate change which will one day wipe us all out. How many years have they been predicting the end of the world now? I’m actually not sure, it’s been so long.
Greenhouses DO NOT work because of Back Radiation.
The current “completely wrong” consensus theory goes something along the lines like this:-
- Visible solar energy warms up the ground passing unabsorbed through the transparent glass.
- The ground emits infra-red radiation.
- The infra-red radiation is sent out into space.
- The glass blocks this, is warmed by the infra-red, and in becoming warmed, returns a portion of IR back to the surface that otherwise wouldn’t have been returned, hence increasing internal temperatures of the greenhouse.
- They then say, this is the “Greenhouse Effect”
So, how does a greenhouse actually works when it is present within an atmosphere?
Figures 1.2 How a Green House Actually Works – Convective Currents
You see what actually happens, the air inside a greenhouse is subjected to a powerful convection current. This means that air which is touching the surface of the warmed floor has heat conducted to it from the floor, cooling the floor but warming the air. This causes this bottom layer of air to warm, as it warms, its density decreases because gases expand when they are warmed because they have more energy. This causes the air to rise within the greenhouse and cooler, denser air above it to drop.
Just imagine pouring some oil and dropping a coin into a bottle of water. The dense coin falls to the bottom but the less dense oil, floats on the top, this is what is happening inside the greenhouse. This cooler air drops to be in-contact with the floor, which in turn gets warmed, rises and continues the cycle.
The first lot of air, which was warmed, when it falls back to the surface, is warmer than when it first started the cycle, it is warmed again, but to an even higher temperature than before and it is this process of heat cycling which causes the temperature of the air to rise dramatically within greenhouses.
This convection current helps spread warm air around the greenhouse and transfers heat to all the objects within the room, including the external surfaces, these external surfaces prevent the air from escaping the greenhouse.
If there was no roof to the greenhouse, the warm gases would escape and the greenhouse would rapidly cool-down, in fact this is a known method of cooling a greenhouse, you just open up the vents and feel the temperature drop.
This process is also occurring outside the greenhouse, however, outside the greenhouse there is no barrier preventing the air from rising, so the air rises miles high and so cools much more before it comes back down again. Inside the greenhouse however, the air only rises a short way, before cycling back down. This is why the air inside the greenhouse is much warmer than the air outside a greenhouse.
So to summate:-
Greenhouses work because of trapped Convection currents not trapped radiation.
I hope this helps put you on the right path and helps you start to see how you may have been misled, by the left leaning educational establishment, if they have failed to educate on how greenhouses actually work. I believe they do this to disempower people.
My next Illumination, will show how it is a complete nonsense, from a mechanical thermodynamic radiation point of view, to think a greenhouse would cause radiation warming. I will show, how a plate in space is warmer, when compared to a plate in space with a greenhouse on it (with no air), which is cooler and I will explain why that is.
Source