With advances in technology, more and more machines, products, and vehicles -created continuously. However, due to those inventions, more and more resource such as electricity, petroleum and water will be consumed. Besides, the progress of medical science extends human's life expectancy and increases population rapidly, especially in China and India. The two big countries, where there are more than 1 billion people, have higher birth rate because the progress of industry and economy improve the quality of life. Unfortunately, natural resources are not unlimited, but will be exhausted and the cost higher. Therefore, now the most essential topics for every country are how to lower the energy cost and how the make the use of natural resources sustainable. As a result, the use of as hydroelectric power, wind power, nuclear power were improved. Applications like diesel vehicle, battery electric vehicle, fan, water spray fan and variable-frequency air conditioner, are used to reduce energy consumption and carbon emission.

As the development of industry and the improvement of quality of life progress, waste gas and water pollute our earth seriously. Earthquake and tsunami happening. in Japan even affected USA which on the other side of Pacific Ocean. Sandstorm in China also made Taiwan suffer. Volcanic eruption in Iceland made transportation in Europe chaotic. Therefore, the butterfly effect pushes most of countries to make new policies based on energy saving and carbon reduction. The weirdness of climate change and the happening of natural disaster make people start to think of how to protect our planet and save our nature. Kyoto Protocol, the first protocol to the United Nations Framework Convention on Climate Change, was officially signed in 1997, and there were more other conferences about environmental protection held in the world.

Electricity consumption in China increases a lot, especially in summer. Shenzhen city, where Pronology Inc. locates , is full of factories. The electricity consumption is usually extremely high, and policy of electricity limitation is always adopted in summer. The limitation is on once a week at least, but sometimes it is two to three days a week. The extremely huge consumption of electricity results from the heavy use of air conditioner in summer. And the electricity price increases accordingly. Factories have to find the solution to decrease the electricity cost as they don't have enough money to cover. Therefore, Pronology Inc. started to substitute water spray fan for air conditioner from 2008.

Water spray fan consists of water spray and fan. Its principle is to put the water into spray device by the engine cyclically; fan facilitates indoor thermal convection. Its electricity consumption is only 10% of the air conditioner. Air and water are used to lower the temperature in the condition of open space. Progress of technology brings several disease. For example, people now easily catch a cold in summer because of the lower indoor temperature; and the skin are made dry when staying for a longer time in airtight space.

Again, the concept of natural environment protection is valued in people's mind. Green buildings, green food, and bicycle have become popular in society. Every extremity is a fault, which is an eternal theory in the universe. Therefore, how to not only make human healthy with the development of technology, but also make our nature sustainable for the next generation, is what we should deeply think of.