A project has been developed by engineering students in Seville to create a new bus shelter where the temperature will be between 22 and 28°C lower than the surrounding air temperature, even if it is 42°C and the ground is at 50°C, which is often the case in the city in high summer.
The team from the University of Seville’s School of Engineering (ETSI) has created an ‘intelligent’ bus shelter capable of detecting when there is a user waiting and activating its thermal conditioning system. In a study entitled ‘Thermal conditioning of short-term stays. Radiant solution in a bus stop in Seville’ published in Science Talks, the scientists explain that the shelter has an underground tank where waste water is stored. This is connected to roof of the shelter, where sensors and solar panels are installed, by a radiant element that replaces the standard glass. The water tanks cool at night and when the water is transported through the radiant element, it produces a significant drop in temperature.
José Sánchez, an industrial engineer from the Energy Engineering department of ETSI, said: “With this water we can ensure that the canopy is between 22°C and 29°C even if the thermometer reads 45°C and the ground is at 50°C”. He added that the system ‘is not like an air conditioner, which produces cold air; rather, the structure of the bus stop itself emits coolness, as happens with refrigerators.’
It is also a self-sufficient installation, he points out, as it only consumes 10% of the energy it produces and the water tank will only have to be changed once during summer, meaning no increase in the cost of the bus stops. “The design is the same as that of conventional stops and will have the same cost,” José said.
Although ETSI has been working on the project since 2016, next year will be the first when one of the bus stops will be installed for public use, with preparatory work already underway.
The invention is not the first time that a cooled shelter has been proposed. In 2020, French advertising display specialist JCDecaux proposed its Natural Cooling bus shelter as a solution to the issue of urban heat islands as part of a range of more modern, innovative bus shelters. JCDecaux’s solution used evaporative cooling, hot air entering the shelter flowing through a wet honeycomb-shaped panel and being cooled naturally by evaporation. The shelter included a tank to gather rainwater from the roof and a system to pipe the water to the cooling module, and fans blow the hot air through the wall on a still day and towards users waiting in the shelter. Solar panels provided power, a real-time control system enabled the shelter to detect weather conditions and human presence in order to function efficiently and only when required, and rainwater was harvested to make the system self-contained.
The company said that tests confirmed the system’s ability to reduce the temperature by between 4°C and 7°C to 36°C and 50% humidity. It is unknown whether any of these shelters were installed or are still in use.