What is the cooling and heating principle of central air conditioning?

The structure of central air conditioning system is shown in Figure 5- 1. According to its working principle, it can be divided into four parts: refrigeration unit, cooling water tower, external heat exchange system and cooling fan. The functions of each part are as follows:

Figure 5- 1 Structure of Central Air Conditioning System

1. Refrigeration pump 2. Fan coil 3. Expansion tank 4. Cooling water tower 5. Cooling pump 6. Condenser 7. evaporator

(1) refrigeration unit

It is used to dehumidify the circulating water leading to each room and change it into "frozen water" after heat exchange inside the unit.

(2) Cooling water tower

It is used to receive the water with heat pumped by the cooling pump and provide cooling water for the water chiller after cooling.

(3) External heat exchange system

The external heat exchange system consists of a chilled water circulation system and a cooling water circulation system. Among them, the function of chilled water circulation system is to pump chilled water from refrigeration unit to refrigeration pipeline through refrigeration, and exchange heat in each room to reduce the temperature in the room; The function of the cooling water circulation system is to pump the cooling water from the cooling water pump to the water tower through heat exchange, cool it in the water tower to reduce the humidity and temperature, and then send it back to the refrigeration unit, so as to circulate continuously and take away the heat released by the refrigeration unit.

(4) cooling fan

There are two kinds of cooling fans: indoor fans and cooling tower fans. The indoor fan is installed in the room that needs cooling, and is used to blow cold air cooled by chilled water into the room, so as to accelerate the indoor air flow and make the temperature drop faster and more evenly. The cooling tower fan is used to cool the spray water entering the cooling tower. The fan generates wind speed and radiates heat to the atmosphere, so that the water temperature entering the tower drops rapidly.