The concept of HVAC includes heating, ventilation, and air conditioning, therefore it has a broader concept 

compared to central air conditioning. The heating system consists of a heat source, heat dissipation equipment, 

heat transmission pipelines, control components, etc. Its technical function is to input heat energy into the space, 

compensate for its heat loss, and meet the indoor temperature requirements. The ventilation system is 

composed of ventilation fans, inlet/outlet or return ports, purification devices, air ducts, and control components. 

Its technical functions include ventilation and air exchange, heatstroke prevention and cooling, improving indoor 

environment, and preventing internal and external environmental pollution. The pressure and temperature sensors 

developed by Longlv Electronics for the HVAC industry have been recognized by well-known enterprises such as 

Yuanda and Shuangliang.