Diary Entry - March

The highlight of this month was a two day residential trip to the eco-cabins at the Centre for Alternative Technology, Wales. The centre is located in the beautiful Dulas valley at the Southern tip of Snowdonia National Park and is designed to educate people about sustainable development and energy use. The students stayed in the purpose built cabins on site which are designed to be self sustaining. The cabins have an electricity system which is independent of the National Grid and they use a combination of photovoltaic cells, wind and water turbines. A diesel generator was available to provide additional power if needed but it was out of order so the students had to ensure they managed their usage !! Students were able to monitor the energy inputs and outputs within each Eco-cabin by using the custom built 'Cabins Monitoring Board'. The monitor also included information regarding  the heating/hot water system, it showed the power left in the storage batteries, the solar energy level, the current windspeed, plus inside and outside temperatures. Wood could be weighed before burning and the gas used for cooking was also measured. The information has been used by the group to look at renewable energy data, weather patterns, usage patterns by different individuals, the energy required for heating (as compared to electricity) and detailed calculations on the efficiency of the turbines and solar cells.

A key aspect of sustainable development is the use of water and waste management. The cabins have therefore been designed with this in mind, incorporating water consumption monitors and low flush toilets. A compost toilet to minimise water consumption and waste processing as the cabins are not connected to a mains water or sewerage supply. The used water is passed through a natural reed bed sewage system containing a variety of plant and animal life, before returning safely to the environment. CAT itself has 7 acres of interactive and educational displays, offering practical ideas and information on environmentally sound practices. The site had working displays of wind, water and solar power, low energy ecological buildings, organic growing and low water sewage systems. Students took part in a guided tour of the centre and had a wind turbines workshop which involved them choosing the size, number and shape of blades for a turbine and testing it's speed in a wind tunnel.

The students who went on the trip have now become far more aware of the fact that they take energy supplies for granted and have become more conscious about saving energy in their everyday lives. They intend to share some of this information on the schools Virtual Learning Environment and to organise an evening where they can showcase their work to parents and the community in May They have been able to use some of the ideas they have experienced to evaluate and improve on their original home designs.

Students have also been continuing to build their Eco-homes and started to research, using primary and secondary research methods, environmentally friendly ways of furnishing, painting and adding appliances to their homes.

Model solar water heaters have been designed, built and tested and the heaters are small enough that the designs can be added to the student's homes. The pupils have learnt some basic scientific principles about insulation, the movement of the Earth in relation to the sun and the movement and absorption of heat. They have estimated the cost of installing this particular type of equipment into a full size home and were surprised by the fact it is much less expensive than solar cells used to generate electricity. The main findings were that the angle needs to be between 30 and 50 degrees from the horizontal, the pipes work best if they are matt and black and that the collector keeps heat in if it is insulated. When the pipes were placed beneath a glass or perspex windows they got hotter as there was no air movement to cool the pipes thus improving the designs.
In order to ensure that the materials used in the model homes will stand up to the rigours of all external factors, students have been devising ways of testing materials. The students have brainstormed ways of protecting their homes against flooding, extreme heat and cold, wind and UV light and they hope to trial some of these ideas in April after a visit from a materials scientist who will help the students devise fair tests that meet their aims. 

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