Cement
Production of cement accounts for nearly 5% of human global emissions. 1 tonne of cement production results in 960 kg of CO2
Biofuels
There is simply not enough agricultural land in the world to replace fossil fuels with biofuels. We will need to use them efficiently, as well as using other sources of power.
Textiles
The production of textiles requires land, energy and water. We need to use these resources efficiently when we design a textile product. Some textile products can help us reduce waste and save energy. More..
What is the problem?
What is the problem?
There are 30 million vehicles on the road in the UK. Each mile a small petrol car travels releases 280 g of CO2 and for a small diesel car 190g of CO2 is released. Driving 2400 miles is the equivalent to the total carbon footprint of the average person in the developing world.
Figures from WRI
Solar hot water system diagram.
Whatever the type of collector used if it is higher than the cylinder, the water in the transfer loop will need to be pumped. Usually the water in the transfer loop is not allowed to mix with the water that will come out of the taps. This is so anti freeze can be added to the water in the loop so water will not freeze and damage the plate on cold nights. The heat is transferred to the tap water by a coil of pipe inside the hot water cylinder. This is called an indirect system.
Most systems have a Control module for the pump. There are at least two sensors which detect the temperature of the water flowing to the plate and temperature flowing back. The simplest systems will switch the pump on if the return temperature is higher. More advanced systems will also control the speed of the pump for maximum efficiency.
