A must-know classic primer for refrigeration people!

First, the basic knowledge of the central air conditioning
1, what is the refrigerant, its working principle?
In the cooled object and the environmental medium between the transfer of heat, and ultimately the heat from the cooled object to the environmental medium of the refrigeration machine in the refrigeration cycle of the working material. The working principle is that the refrigerant absorbs the heat of the cooled material in the evaporator and evaporates.
2.What is the refrigerant carrier and what is its working principle?
The refrigeration unit of the cooling capacity to be cooled medium medium material. Such as commonly used air conditioning chilled water, which is cooled down in the evaporator, and then transported over long distances to cool the object to be cooled.
3, what is sensible heat?
That is, without changing the form of the material and cause its temperature change of heat is called sensible heat. Changes in sensible heat can be measured with temperature measuring instruments.
4, what is latent heat?
Does not change the temperature of the substance and cause changes in the physical state (also known as phase change) of the heat is called latent heat. Latent heat change can not be measured by temperature measuring instruments.
5, what is the dynamic pressure, static pressure, full pressure?
When selecting an air conditioner or fan, the three concepts of static pressure, dynamic pressure, and full pressure are often encountered.
Static pressure (Pi): Due to the irregular movement of air molecules and the pressure generated by the impact on the pipe wall is called static pressure. Calculation, the absolute vacuum for the calculation of the zero point of the static pressure is called absolute static pressure. Atmospheric pressure as the zero point of the static pressure is called the relative static pressure. Air conditioning in the static pressure of the air are relative static pressure. Static pressure above atmospheric pressure is positive, below atmospheric pressure is negative.
Dynamic pressure (Pb): the pressure generated by the air flow, as long as the air flow in the duct has a certain dynamic pressure, the value is always positive.
Full pressure (Pq): full pressure is the algebraic sum of static and dynamic pressure: Pq = Pi + Pb. The full pressure represents the total energy of 1 m3 of gas. If atmospheric pressure is the starting point for calculation, it can be positive or negative.
Second, the classification of air conditioning
1.According to the purpose of use, air conditioning can be divided into which categories?
Comfort Air Conditioning: Requirements for the appropriate temperature, comfortable environment, temperature and humidity of the regulation of precision without strict requirements for housing, offices, theaters, shopping malls, gymnasiums, automobiles, ships, airplanes and so on.
Process air-conditioning: the temperature has a certain degree of regulation accuracy requirements, in addition to the cleanliness of the air should also have higher requirements. It is used in electronic device production workshop, precision instrument production workshop, computer room, biological laboratory and so on.
2.According to the way of air treatment, which categories can be divided into?
Centralized air-conditioning: air treatment equipment is concentrated in the central air-conditioning room, and the treated air is sent to the air-conditioning system of each room through the air duct. Applicable to large areas, room concentration, the room heat and humidity load is relatively close to the place of choice.
Semi-centralized air conditioning: both the central air conditioning and air handling end device air conditioning system. This system is more complex, and can achieve a high degree of regulation accuracy. It is suitable for workshops and laboratories that have high requirements for air precision.
Localized air conditioning: each room has its own equipment to deal with air conditioning, such as split air conditioners. Can also be centralized by the pipeline to the hot and cold water fan coil air conditioner system, each room as needed to regulate the temperature of the room.
3, according to the cooling capacity can be divided into which categories?
Large air-conditioning units: such as horizontal assembly shower type, table cooling air-conditioning unit, used in large workshops, movie theaters and so on.
Medium-sized air-conditioning units: such as water chillers and cabinet air-conditioning units, applied to small workshops, computer rooms, venues, restaurants and so on.
Small air-conditioning units: split air-conditioners, used in offices, homes, guest houses and so on.
4.According to the amount of fresh air, air conditioners can be divided into which categories?
DC system: the air handled by the new air, sent to the rooms into the heat and humidity exchange discharged to the outdoors, there is no return air duct.
Closed system: the air conditioning system handles all the air recirculation, without supplementing the fresh air system.
Mixed system: air conditioner air handled by the return air and fresh air mixed.
5, according to the air supply speed classification?
High-speed system: the main air duct air speed 20-30m / s.
Low-speed system: the main air duct wind speed of 12m / s or less.
Third, the common terminology of air conditioning
1, nominal cooling capacity
Unit time, the air conditioner in the nominal refrigeration conditions from the space area or the room excluded from the heat, called the nominal cooling capacity.
2, nominal heat
Unit time, the air conditioner in the nominal heating condition to the space area or room heat release.
3.Energy Efficiency Ratio (EER)
The size of the cooling capacity per unit of motor input power. Is a reflection of the air conditioner cooling operation of the cooling capacity and cooling power ratio, unit W / W.
4, performance parameters (COP)
Refrigeration compressor performance parameters COP value, that is: the unit shaft power of refrigeration.
5, commonly used air conditioning units of measurement and conversion:
A kilowatt (KW) = 860 calories (Kcal/h).
A big card (Kcal/h) = 1.163 watts (w).
1 Cooling Ton (USRT) = 3024 Kcal/h.
One cold ton (USRT) = 3517 watts (w).
Fourth, common air conditioning unit
1, water-cooled chiller
Water-cooled chiller belongs to the central air-conditioning system in the refrigeration unit part of the refrigerant carrier for water, known as chiller, and condenser cooling for the use of room temperature water heat transfer cooling to achieve. Therefore, it is called water-cooled unit, and water-cooled unit is called air-cooled unit, air-cooled unit of the condenser by the forced ventilation with the outdoor air heat transfer to achieve the purpose of refrigeration.
2.VRV system
VRV system is the refrigerant flow variable system. Its form for a group of outdoor units, by the function of the machine and constant speed machine, variable frequency machine. Through the parallel outdoor unit system, the refrigeration pipeline is centralized into a pipeline system, which can be easily matched according to the capacity of the indoor unit.
A maximum of 30 indoor units can be connected to a group of outdoor units, and the capacity of the indoor units can be adjusted within 50% to 130% of the capacity of the outdoor units.
3.Module Unit
In the VRV system based on the development of heat to come, modular machine will change the traditional Freon pipeline into a water system, the indoor and outdoor units will be merged into a refrigeration unit, the indoor unit is changed to fan coiler. The cooling process is realized by utilizing the heat exchange of the carrier refrigerant water. Module machine can be automatically adjusted according to the requirements of the cold load to start the number of units to achieve a flexible combination of this name.
4.Piston chiller
Piston chiller is the realization of the refrigeration cycle of piston refrigeration compressor, auxiliary equipment, emergency accessories compactly assembled together specifically for the purpose of air-conditioning cold use of the overall refrigeration device. Piston chiller single refrigeration from 60 to 900KW, suitable for small and medium-sized projects.
5.Screw chiller
Screw chiller is a large and medium-sized refrigeration equipment to provide chilled water. Commonly used in national defense research, energy development, transportation, hotels, restaurants, light industry, textiles and other sectors of the air conditioning, as well as water conservancy and power projects with chilled water. Screw chiller is a complete refrigeration system composed of screw refrigeration compressor, condenser, evaporator, and self-control components and instruments. It has a compact structure, small size, light weight, small footprint, easy operation and maintenance, smooth operation and other advantages, and thus gained wide application, its single refrigeration capacity from 150 to 2200KW, suitable for medium and large-scale projects.
6.Centrifugal chiller
Centrifugal chiller is a centrifugal refrigeration compressor and supporting evaporator, condenser and throttle control device and electrical table composed of the entire chiller, single cooling capacity from 700 to 4200KW, which is suitable for large, extra-large-scale projects.
7.Lithium bromide absorption chiller unit
Lithium bromide absorption chiller to thermal energy as the driving force, water as refrigerant, lithium bromide solution as an absorbent, to produce refrigerant water above 0 ℃, can be used as an air conditioner or production process cold source, lithium bromide absorption to thermal energy as the driving force, common direct-ignition, steam, hot water type of the three categories, its cooling capacity ranges from 230 to 5,800KW, suitable for medium-sized, large, very large-scale projects.
Fifth, the central air conditioning unit classification
Central air conditioning unit is the core part of the central air conditioning system. Reasonable selection of units for a central air conditioning project is critical. On the cooling (hot) water unit cooling method and structure classification, can be divided into the following types.
Six, refrigeration and air conditioning 20 core components
1.Compressor
Is the core of the entire air conditioning system, but also the source of system power. The power of the entire air conditioning, all provided by the compressor. Compressor according to the compression method, volumetric compressor can be divided into two categories of piston and rotary. Specifically: piston, slide, screw, scroll, centrifugal, rotary.
2, condenser
Role is to compressor discharge of high temperature and high pressure refrigerant superheated vapor cooling into liquid or gas-liquid mixture. Can be divided into water-cooled, air-cooled, water and air mixed cooling three types.
Water-cooled condenser: The heat of the refrigerant in the condenser is taken away by the cooling water. The cooling water can flow once or be recycled. When circulating, a cooling tower or cooling pool is required. Water-cooled condenser is divided into several types such as shell and tube, casing type, plate type and spiral plate type.
Air-cooled condenser: The heat released by the refrigerant in the condenser is taken away by the air, and the refrigerant is condensed in the tube. There are natural convection air-cooled condenser and forced convection air-cooled condenser in this type of condenser. Usually, air-cooled condensers are also called air-cooled condensers.
Water and air cooling type: the heat released by the refrigerant in the condenser is taken away by the cooling water and air at the same time, and the cooling water absorbs the latent heat of vaporization when it is evaporated outside the tube by spraying, so that the refrigerant in the tube is cooled and condensed, so the water consumption is less.
3.Evaporator
The role of the use of liquid low-temperature refrigerant in the low-pressure evaporation, into vapor and absorb the heat of the cooled medium, to achieve the purpose of refrigeration. Types of evaporator: evaporator according to the different cooling medium, divided into cooling liquid refrigerant, cooling air or other gases of the two types.
Cooling liquid refrigerant: tank type (immersed) evaporator (including vertical tube type, spiral tube type, snake type), plate evaporator, spiral plate evaporator, shell and tube evaporator (including horizontal evaporator, dry evaporator) and so on.
Cooling air evaporator: air-conditioning Fin Evaporator, freezing and refrigerating air-air cooler (chiller) and tube evaporator.
4.Throttling mechanism
Make the condenser out of high-pressure liquid throttling pressure reduction, so that the liquid refrigerant in the low pressure (low temperature) vaporization and heat absorption. Therefore, it is to maintain the condenser for high-pressure, evaporator for low-pressure important parts.
Throttling components according to the form, can be divided into Capillary Tube and expansion valve, capillary tube used in smaller refrigeration equipment, such as refrigerators installed in the condenser and evaporator between the capillary tube that is one of the throttling mechanism.
Expansion valve used in larger refrigeration equipment, in large and medium-sized devices in the application of the throttle mechanism for the throttle valve, commonly used throttle valve there are three kinds of, namely, manual expansion valve, float valve and thermal expansion valve, the last two kinds of automatic adjustment of the throttle valve. Expansion valves can be divided into electronic expansion valves and thermal expansion valves according to the type of expansion.
5.Gas-liquid separator
Installed at the inlet end of the compressor, mainly to prevent the return of the compressor low-pressure low-temperature vapor carrying too many droplets, to prevent the liquid refrigerant into the compressor cylinder, to prevent liquid shock, the separator also has a filter, back to the oil, liquid storage and other functions.
Gas-liquid separator should be noted when using:
1, as close as possible to the compressor;
2, in the reversing system, the gas-liquid separator should be installed between the reversing valve and the compressor;
3, the correct installation of the inlet (from the evaporator) outlet (go to the compressor suction port);
4, must be installed upwards;
6, fan
Fans are AC single and three-phase induction motors combined with impellers. Fans are divided into axial flow fans and centrifugal fans.
Fans include two series of fixed-speed and variable-speed. Fans are divided into metal air blades, plastic air blades and metal cast air blades, etc., and there are various leaf types.
7.Liquid Reservoir
Refrigeration system in the high-pressure reservoir (also known as liquid storage cylinder) is installed in the condenser and the expansion valve between the form of liquid storage device has a variety of unidirectional and bidirectional points; there are vertical and horizontal points. Its function can be summarized in several aspects:
Store condenser condensate: avoid condensate in the condenser accumulates too much and make the heat transfer area become smaller, affect the heat transfer effect of the condenser.
Adapt to the evaporator load changes on the demand for supply: in the evaporation load increases, the supply also increases, by the liquid storage tank of the liquid replenishment; load becomes small, the need for liquid volume also becomes smaller, excess liquid stored in the liquid storage tank.
As a liquid seal between the high and low pressure sides of the system: because the liquid outlet pipe is inserted under the liquid surface, it prevents the vapors and non-condensable gases on the high pressure side from entering the low pressure side. At the same time, the reservoir also plays the role of filtration and noise reduction.
8.Oil separator
Installed between the compressor and condenser, it works as follows: compressor exhaust is a mixture of refrigerant and lubricating oil, through the oil separator of the larger cavity deceleration, foggy oil will be gathered in the impact of the surface, when the aggregation into a larger oil droplets, flow to the bottom of the oil separator, and through the oil return device back to the compressor.
9.Gas-liquid separator
The gas-liquid separator is installed at the air inlet of the compressor. The gas-liquid separator prevents the compressor from damaging the compressor by liquid shock caused by the liquid refrigerant sucked into the air inlet of the compressor.
10.Filter drier
The role of the filter is to prevent the refrigerant contains water or magazines into the refrigeration system. When the high temperature liquid from the condenser into the expansion valve, the temperature of the liquid will drop dramatically, generally below zero, then if the system contains water, due to the expansion valve through the cross-section is very small, it will be prone to the phenomenon of ice blockage, affecting the normal operation of the system.
11, four-way reversing valve
Four-way reversing valve for central air conditioning, unit air conditioners and other heat pump air conditioning systems, it is used to switch the flow path of the refrigerant to achieve the purpose of cooling and heating.
12.Water pump
It is a tool used to accelerate the flow of water in order to enhance the effect of water heat exchange in the heat exchanger.
13.Water flow switch with
For the control of the fluid flow in the pipeline or cut off the flow protection, when the fluid flow reaches the set value, the switch automatically cut off (or turn on) the circuit.

Xinxiang Yukun Refrigeration Technology Co. is a production and sales of refrigeration two apparatus parts and sheet metal products, mainly engaged in condenser, evaporator, heat exchanger, reservoir, filter drier, fin evaporator (condenser), Stamping Parts, sheet metal parts, aluminum tubes for refrigeration, etc.

Our company has always had strict quality control standards in the market of refrigeration and heat exchange equipment, focusing on providing customised services to our customers. Not only do we have high requirements for the selection of raw materials, but we also keep up to date with the latest production processes and have high testing standards.

Our company mainly produces products for:Fin Evaporator.Fin Type Condenser.Capillary Tube. Coolant Reservoir.Plate Reinforcement Parts. Stamped Parts .Aluminum Tube.Instrument Testing Equipment.

Supermarket Refrigeration Show Case Copper Condenser Coil
1. OEM or ODM can be accepted
2. Fin type: Louver or corrugated
3. Be customerized according to samples and drawings.
4. High quility and low price and energy saving 60% (CE, RoHS, EMC and ISO9001 certification) The CD series products can be used in Various specificantion Condensing Units .
They are air cooled heat exchangers for refrigeration system. They are divided in 4 group:CD,CDC,CDS and CDV.All the products have been tested on 2.8MPa air leakage,and the system is disposed of pollution,applicable to R22,R134a,R404A,R407C systems.

Our company mainly produces products for:Fin Evaporator.Fin Type Condenser.Capillary Tube.Aluminum Coolant Reservoir.Plate Reinforcement Parts.Stamped Parts.Aluminum Tube.Instrument Testing Equipment.
Supermarket Refrigeration Show Case Copper Condenser Coil
1. OEM or ODM can be accepted
2. Fin type: Louver or corrugated
3. Be customerized according to samples and drawings.
4. High quility and low price and energy saving 60% (CE, RoHS, EMC and ISO9001 certification) The CD series products can be used in Various specificantion Condensing Units .