Essential knowledge of air conditioning HVAC (Part 1)

Refrigerant: Refrigerant is the refrigerant, is the refrigerant system to complete the refrigeration cycle of the working medium. The refrigerant absorbs the heat of the cooled object in the evaporator and evaporates, and the heat is transferred to the surrounding air or water in the condenser and condensed into a liquid. The refrigerator achieves the purpose of refrigeration by means of the state change of refrigerant.

Cooling capacity: The heat absorbed by the low-pressure side refrigerant in the evaporator per unit time when the air conditioner is running. The commonly used unit is W or KW.

Heat pump heat: air conditioner for heat pump heating operation (heat pump auxiliary electric heater should run at the same time) unit time into a confined space, room or area of heat.

Fan coil unit: set the common heat exchange equipment in the central air conditioning system, composed of fin tube and fan, etc., the carrier refrigerant flows through the fan coil unit (inside the tube) and the air at the tube heat exchange, so as to cool the air. Fan coil units are air cooling equipment.

Coefficient of performance: The ratio of the amount of refrigeration (heat) produced in the refrigeration (heat) cycle to the electrical power consumed by refrigeration (heat) is the coefficient of performance. For cooling, it is called energy efficiency ratio, denoted by EER; for heating, it is called performance coefficient, denoted by COP.

Secondary coolant: Secondary coolant is an intermediate medium used in indirect cooling systems to transmit the amount of cold. After the carrier refrigerant is cooled by the refrigerant in the evaporator, it is sent to the cooling equipment to cool, absorb the heat of the cooled object or environment, and then return to the evaporator to be cooled by the refrigerant again, so as to achieve the purpose of continuous refrigeration.

Water-cooled chiller unit: Water-cooled chiller unit belongs to the refrigeration unit part of the central air conditioning system. Its carrier refrigerant is water, which is called the chiller unit. The cooling of the condenser is realized by the heat exchange and cooling of water at room temperature, so it is called the water-cooled unit. The opposite of the water cooler is called the air cooling unit. The condenser of the air cooling unit achieves the cooling purpose by forced ventilation and heat exchange of the air in the room.

Cooling tower: A special device for cooling water with the help of air, usually installed on the top of a building. In refrigeration, electric power, chemical and many other industries. Hot cooling water discharged from the condenser and other equipment is recycled after cooling by the cooling tower.

Modular machine: it will change the traditional Freon pipeline into water system, the indoor and outdoor units into refrigeration units, indoor units into fan coil units. The cooling process is realized by using the heat transfer of secondary refrigerant water. The modular machine is named because it can automatically adjust the number of starting units according to the requirements of cooling load and realize flexible combination.

Multi - line: multi - line is not the traditional sense of central air conditioning, the traditional sense of central air conditioning is water into the fan coil, multi - line is directly through the fluorine into the fan coil. Therefore, the pipeline is destined to be not too long, and the energy loss of the multi-line in the pipeline is larger than the machine, if the pipeline leakage of the multi-line, many times can not be maintained.

Frequency conversion multi - line is not all compressors are frequency conversion, generally only a compressor is frequency conversion, the other is fixed frequency. Multi - line pipeline system is more complex control system is more complex.

Modular machine and screw machine, multi-line difference: modular machine and screw machine are water system, that is, from the main machine is frozen water, for indoor end wind disk and other equipment for refrigeration. The multi-line is a fluorine system. The refrigerant (R22 or R410a refrigerant, etc.) comes out from the main engine. The end of the refrigerant is also connected with the fluorine pipe. Similar to a drag a household air conditioning unit, but into a drag more, and add frequency conversion (DC frequency conversion or digital scroll frequency conversion) technology.

The difference between air cooling machine and water cooling machine: air cooling machine refers to the host heat dissipation by fans, water cooling machine is only the host heat dissipation by water. The air cooler has compact structure, no special room and simple maintenance. The disadvantage is that refrigeration and heating is greatly affected by climate, and the energy efficiency ratio is slightly lower than that of the water cooler. Water cooler generally needs a special room, with cooling tower, the system is slightly complex, the maintenance is slightly complicated, most can not heat, the advantage is that the cost is lower than the air cooler, the energy efficiency ratio is slightly higher than the air cooler.

Energy efficiency ratio: the energy efficiency ratio of an air conditioner is the ratio of nominal cooling capacity (heat production) to operating power. The mathematical expression of EER and COP is: EER= cooling capacity/cooling consumption power COP= heating production/heating consumption power. The higher EER and COP, the lower energy consumption of the air conditioner and the higher performance ratio.