The Hong Kong Polytechnic University will come up with the fourth-generation Nano solar panel in August, noted Sina.com. It will not only reduce thickness by 70% to 1.5 mm but also increase about 30% of conversion efficiency in order to provide air conditioning to solar vehicles better.

In 2009, Eric Cheng, a professor of Department of Electrical Engineering at the Hong Kong Polytechnic University, developed the first-generation roof-top solar air-conditioning system to reduce carbon emissions in tons per year for pilot-run taxies and light buses.

However, as first-generation system soaked up the sun for six hours, air-conditioning could only be supplied for half an hour. A bus driver which drove the earliest light bus equipped with the system indicated, air-conditioner was usually broken during the summer and it could be very hot inside the bus. Cheng pointed out there was a huge improvement for the third-generation system – after soaking up six hours of sun, air conditioning can be supplied for six hours.