A group of secondary students from Cheung Sha Wan Catholic Secondary School won the Hong Kong Student Science Project Competition recently with an environmentally-friendly house. Their project was also first runner-up in the Applied Science Category of the 40th National Primary and High Schools Science Fair held in Taiwan in March. This summer, the group will fly to Singapore to participate in the second Asia-Pacific Economic Co-operation Youth Science Festival. The house uses a thermoelectric converter to maintain a constant internal temperature. As an electric current runs through the converter, one side will absorb heat (cooling) while the other side will release heat (heating). A solar panel and incinerator that burns plant material help to provide environmentally-friendly electricity for the converter. Additional energy can be stored in a lead-acid battery which would supply energy to the converter at night. The group of Form Six students were Tang Ho-yin, 18, Jeffrey Lee Chi-wai, 18, Cheung Pak-ki, 17, Chan Cho-lit, 17, and Au Yat-fung, 17. Cho-lit, the chairman of the school's physics and electronics club, said the house was the result of trial and error. 'In class, we didn't have to consider outside factors that would influence the result. But in practice, we encountered many difficulties. 'For example, how do you make automatic curtains and ensure the solar panels collect the maximum amount of sunlight? All these things are not taught in class.' Although the house was environmentally-friendly and the converter twice to three times more durable than air-conditioners, production costs at this stage were high. 'Therefore the house cannot be widely used unless there is a way to lower the costs,' Cho-lit said. Chi-wai said he enjoyed the process of invention and nothing else could provide the satisfaction that science did. 'Isn't it amazing to develop a real model from an idea? Every invention from a light bulb to a microwave oven starts from the imagination. 'I love science because it is very relevant to our daily lives.' Yat-fung said: 'Perhaps I am the kind of person who doesn't like to memorise things. 'The arts also requires creativity. But I prefer science because it is more objective and rational.'