People walk through a water mist machine installed by the city to assist people in coping with the heat on a torrid day in Bucharest, Romania, on Monday. VADIM GHIRDA/AP

At an air conditioner factory run by Midea Group, a leading Chinese home appliance manufacturer, in the Shunde district of Foshan, Guangdong province, workers are putting in overtime to ramp up production of portable split air conditioners.

Portable split air conditioners made by Chinese home appliance manufacturers have become highly sought-after, trendy items in Europe, as temperatures in many European countries have broken historical records since late May.

"We are leveraging flexible manufacturing capabilities to quickly respond to demand for such air conditioners by European consumers," said Xiong Xueqin, sales director of Midea RAC Europe Region.

The units will be transported via China-Europe freight trains to meet demand during Europe's peak summer season, with a transit time of 15-25 days, according to Xiong. The railway shipment is about 25 days shorter than sea shipping.