Entering the new century, central air conditioning has become a common feature in ordinary households. More and more people choose to live, work, entertain and shop in the environment of central air conditioning. With the development of the economy and the improvement of people's living standards, buildings equipped with central air conditioning have sprung up like mushrooms, appearing in every corner of urban and rural areas. Ensuring the normal operation of central air conditioning and providing users with a healthy, comfortable, safe and civilized indoor environment; in view of the current situation where there is a relative shortage of talents and the operation quality of central air conditioning is generally poor, the society urgently needs a large number of skilled professionals with high quality; in order to solve the problem that major and secondary vocational schools lack teaching and experimental equipment for central air conditioning, our company has invested a large amount of money and successfully developed the BR-221B type central air conditioning experimental equipment applicable for teaching by professional engineers.