/kloc-at the beginning of the 9th century, Sadi karnot, a French scientist, put forward the theory of Carnot cycle for the first time in 1824, which became the origin of heat pump technology. 1852, British scientist L.Kelvin put forward the idea that refrigeration device can be used for heating, and inverse Carnot cycle can be used as heat pump for heating. He was the first to put forward a formal heat pump system, which was called "heat multiplier" at that time. After that, many scientists and engineers did a lot of research on heat pump, which lasted for 80 years.

19 12 Zurich, Switzerland, successfully installed a set of heat pump equipment with river water as the low-level heat source, which is the early water source heat pump system and the first heat pump system in the world. The heat pump industry developed rapidly from the 1940s to the early 1950s. Household heat pumps and industrial building heat pumps began to enter the market, and heat pumps entered the initial stage of development.

Since the 1970s, the heat pump industry has entered a golden age, and countries all over the world attach great importance to the research of heat pumps. For example, the International Energy Agency and European countries have made large-scale heat pump development plans, and new heat pump technologies are emerging one after another, and the uses of heat pumps are constantly being explored, which are widely used in air conditioning and industrial fields and play an important role in energy conservation and environmental protection.

2 1 century, with the appearance of "energy crisis", the price of fuel oil suddenly rose. The improved and mature heat pump has re-entered the historical stage and become the most valuable new energy technology at present because of its characteristics of efficient recovery of low-temperature environmental heat energy, energy saving and environmental protection.

The former International Thermal Energy Agency set up an international heat pump center and heat pump scheme to promote and coordinate the application and development of heat pump technology in all countries in the world. The governments of the United States, Canada, Sweden, Germany, Japan and South Korea have issued special official guidelines to promote the social application of heat pump technology.

Compared with the development of heat pump in the world, the research of heat pump in China started 20-30 years later. After the founding of New China, with the arrival of a new upsurge in industrial construction, heat pump technology began to be introduced into China. After entering the 2 1 century, the rapid urbanization of China coastal areas, the growth of per capita GDP, the 2008 Beijing Olympic Games and the 20 10 Shanghai World Expo have stimulated the development of the air-conditioning market in China and promoted the more and more extensive application of heat pumps in China. The development of heat pump is very rapid, and the research of heat pump technology is constantly innovating.

Since the start of 200 1 heat pump, after five years of cultivation, China's heat pump industry has begun to shift from the introduction period to the growth period. The rapid development of heat pump industry, on the one hand, benefits from energy shortage, making the advantages of heat pump energy saving more and more obvious, on the other hand, it has a lot to do with the participation of many forces in promoting industrial technological innovation.