The sky-high price and high cost of solar air conditioning.

Researchers and engineers have been working on developing machines that use solar energy to cool rooms. However, it can never compare with the traditional plug-in air conditioning box. According to the evaluation of Germany Voss solar energy information consulting company Solid, the total output of newly installed electric air conditioners is as high as 250,000 MW every year, and only a small part of them are environmentally friendly air conditioners. "So far, this new technology is not economically feasible," said Oskar Wolf, an expert in solar refrigeration technology at Solid. Energy regeneration refrigeration system needs 24-30 cents per kilowatt hour, which is twice the cost of traditional air conditioning.

The cooling liquid evaporated by heat is condensed and sprayed on the heat exchanger, and then evaporated again. The evaporated heat energy is used to extract the moisture in the air, and the air continues to flow into the heat exchanger to be cooled, finally bringing coolness to the room.

Wolf said that the problem is that even such a small machine 15kW needs a lot of electricity and high temperature as high as 100 degrees Celsius. In addition, it is difficult to calibrate solar energy and refrigeration systems. "It took us a long time to master this technology."

However, the market for clean and environmentally friendly air conditioners is quite huge. According to the forecast of the International Energy Agency (IEA), due to the impression of climate change, the demand for air conditioning in Europe will increase by more than 10% by 2020. Solar refrigeration equipment can meet these needs, while avoiding increasing carbon dioxide emissions and helping to reduce the negative impact on the climate. At the same time, it can also reduce the noon power consumption peak, which is conducive to ensuring the stable work of the transmission network.

The German government provides health subsidies for users who buy and install environmentally friendly air conditioners. At the same time, Germany's Fuxing Credit Bank will also provide up to 30% investment sponsorship for enterprises with solar panels over 40 square meters.

For example, subsidies are provided for adsorption refrigeration equipment. Bernd Hebenstreit, sales manager of EAW solar panel manufacturer in East Germany, said: "We are looking for opportunities to talk to the national environmental department." Similar movements have taken place all over Europe. The EU renewable energy directive implemented on May 1 2009 mentioned the expectation of popularizing this technology. Member States should adopt laws and regulations to promote the use of solar refrigeration, heating and air conditioning.