Advantages, classification, and composition of central air conditioning (recommended collection)

Central air conditioning system – advantages:

Economical and energy-saving:

The host is controlled by a microcomputer, the fan coil unit at the end of each section can adjust the temperature by itself, and the interval can be closed when there is no one, and the system is automatically operated according to the actual load.

Environmental protection:

The whole system is a closed pipeline system, which can avoid the pollution of the system by impurities such as mold and dust, so that the environment is fresh and beautiful, especially suitable for the use of high-end villas, high-end apartments and office buildings.

Space-saving:

The main engine is small in size, does not have a computer room, does not need to occupy the equipment layer, reduces the investment in public facilities and civil engineering, and the indoor end is hidden in the ceiling, which is easy to cooperate with the decoration of the house.

Personalize:

The central air-conditioning system takes the interval as a unit to meet the needs of users in different sections, and the indoor end installation adopts a hidden method, which does not affect the aesthetics of the room, does not occupy the indoor space, and adapts to the individual needs of users.

Simplified management:

The separate control system for different sections is owned by the user, and the property rights relationship is clear, which can simplify the management of air-conditioning facilities.

Raise the grade:

The central air-conditioning host can avoid damaging the overall appearance of the building, so that users can fully enjoy the high-end comprehensive environment while improving product quality and mass sales grade.

Ease of Investment:

According to the development of mass merchandising, the air conditioning system can be invested in phases and batches, and the grade of mass merchandising can be improved, so the capital turnover is fast, and the funds are effectively used for further development.

Central air-conditioning system - household classification

1. Duct machine:

A fixed-frequency outdoor unit, a fixed-frequency indoor unit, send hot and cold air to each room through the air duct, can easily introduce outdoor fresh air; it is easier to humidify the air and other centralized treatment, it is a cheap machine, the noise of each room is reasonably designed to increase by only 1~3 decibels, the bedroom does not have to hang the ceiling, each room can be higher than the temperature set by the main thermostat, the temperature is controlled, there can be a certain proportion of energy transfer, to achieve the effect of energy saving and speeding up the cold and hot speed of air conditioning.

The local noise of the indoor unit is large, and the actual measurement is between 42~52 decibels according to the different installation conditions on site, which is very professional in design and installation requirements.

Second, one tow multi-unit:

1. Fixed frequency multi-connection

Concentrate the split air conditioner into an outdoor unit, at most there are three compressors in one tow three, and the refrigerant system is independent; change the surface-mounted wall-mounted indoor unit to a hidden type; the difficulty of introducing fresh air is a deformation of the split air conditioner, and the noise of the fan in the bedroom should increase by 7~14 decibels from low to high, and the maximum is 50 decibels. Each bedroom needs to add a ceiling with a length of more than 1.2m, a width of 0.6m and a height of 0.3m, and a manhole is required, and each internal machine needs to have a condensate discharge pipeline.

The refrigerant system is independent, but there is a common point in the circuit part, such as the failure of the external fan, the external unit temperature probe, the pressure protection or the local short circuit of the electrical appliance, the whole set of machines will not be able to operate.

2. Fixed and frequency conversion are more than one delay

Among them, there are 1~2 inverter compressors or 1 fixed frequency compressor, and there is radio frequency interference on the circuit, which has an impact on the computer. Manhole fresh air introduction ceiling and condensate are the same as multi-line, the design of the branch device of the fluorine pipe is reasonable, the upper and lower floors share one machine, the pipeline requirements are higher, and it is easy to have the situation that the effect of the end of the machine is too poor when it is fully opened.

3. Hot and cold water machine:

Fixed frequency hot and cold water machine or inverter hot and cold water machine

With the downsizing of large central air conditioners, the condenser is changed from water-cooled to air-cooled, and hot and cold water is pumped to the fan coil unit. The introduction of fresh air, manholes, ceiling condensate discharge, and noise indicators are the same as those of the multi-unit. However, the hot and cold water pipes were added, and due to the large temperature difference, the sealing problem was prominent, and the water leakage caused great damage to the decoration. In addition, large central air conditioning evaporators are regularly cleaned and pickled, and there is no good solution for household cold and water heaters, and the efficiency of cold and heat exchangers will be greatly reduced when used for a long time. If it can be combined with a central water treatment system, the above difficulties can be overcome.

The use of air conditioning in a single room, the fan coil unit in other rooms has hot and cold water pipes flowing through, which will also produce energy consumption; it is more popular to use solenoid water valve to close the water channel; in addition to the cost factor, it will also make the local water flow rate too high, resulting in the problem of noise.

Central air conditioning system – how it works

The basic working process of the cold (hot) water unit is:

The outdoor refrigeration (hot) unit cools the cold (hot) medium water (or heats it up), and then the cooled refrigerant (hot) water is transported by the water pump to the fan coil unit installed indoors, and the fan coil unit adopts the local return air to exchange heat with the indoor air to achieve the purpose of indoor air treatment. 　　

The basic working process of the air duct (road) unit is:

During cooling, the outdoor refrigeration unit absorbs the refrigerant vapor from the indoor unit, compresses and condenses it, and then delivers the liquid refrigerant to each indoor unit. During heating, the outdoor refrigeration unit absorbs the refrigerant vapor from the condenser and delivers the steam refrigerant to each indoor unit after compression, and the indoor unit sucks in the air through the return air outlet arranged on the ceiling, carries out heat exchange and sends it into the air duct (channel) installed in the ceiling of each indoor room, and transmits air to each indoor room through the diffuser on the air outlet. The air duct (road) is designed with a fresh air valve and an exhaust air door, which can replace the air in a certain proportion to ensure the quality of indoor air. 　　

The basic working process of the inverter one-to-multiple unit is:

During cooling, the outdoor refrigeration unit absorbs the refrigerant vapor from the indoor unit under pressure

Central air-conditioning systemThe central air-conditioning system delivers liquid refrigerant to each indoor unit after shrinking and condensing. When heating, the outdoor refrigeration unit absorbs the refrigerant vapor from the condenser and compresses it to deliver the steam refrigerant to each indoor unit. Each indoor unit is arranged on the ceiling by concealed installation. The air is sucked in through its return air outlet, sent in after heat exchange, and then the treated air is sent back to the room by means of local return air from the air supply outlet.

The unit is controlled by a microcomputer in terms of energy regulation, and the inverter compressor of the outdoor unit automatically adjusts the working state of the compressor according to the changes of indoor cooling and heating loads to meet the requirements of indoor cooling and heating loads.

Central air-conditioning system – commercial system

Single-cool:

The hot and humid air in the room is inhaled, and the water vapor in it is condensed through the evaporator, and then the dry and cool air is sent into the room to cool down and reduce humidity.

Hot & Cold:

It can not only cool down and reduce humidity, but also heat and heat. The heating method can be divided into heat pump type and electric heating type. When the heat pump air conditioner is heating, the outdoor air temperature must be above 5°C to work normally. 　　

Window:

It is a combination of air conditioning, refrigeration, ventilation and control systems. 　　

Mobile:

The difference between it and window air conditioners is that it adopts a water-cooled method, and the condensate is discharged through a hose, which can be moved indoors at will without installation.

Segment formula:

It consists of an indoor chassis and an outdoor chassis, which combines compressors, condensers and axial fans in the refrigeration system. 　　

Inverter air conditioner:

It is composed of computer-controlled inverter and inverter compressor, which uses inverter control technology to make the air conditioner automatically select the refrigeration, heating and dehumidification operation mode according to the ambient temperature, so that the room can quickly reach the required temperature in a short time, and in the state of low speed and low energy consumption with a small temperature difference fluctuation, to achieve fast, energy-saving and comfortable temperature control effect.

Water-cooled:

By the indoor coil, the outdoor unit can be a water-cooled screw or a cooling belt (this is also a single cooling type), not to mention the east and east of the unit, you should know the four major components. 　　

Air-cooled:

The indoor coil unit, the outdoor unit is an air-cooled screw or module unit. 　　

The central air conditioning system is composed of a series of moving equipment (such as pumps, fans and compressors) that drive fluid flow, various types of heat exchangers (such as fan coil units, evaporators, condensers and intermediate heat exchangers, etc.) and pipes (such as air ducts, water pipes and refrigerant pipes) and valves connecting various devices. The system can generally be divided into the following five cycles:

1. Indoor air circulation;

2. Cold water circulation; 　　

3. Refrigerant circulation; 　　

4. Cooling water circulation; 　　

5. Outdoor air circulation.

Central air-conditioning system - the main component equipment

1. According to the medium used to bear the indoor heat and humidity load, it can be divided into:

1. Full air system

2. Whole water system

3. Air-water system

4. Refrigerant system

2. According to the concentration of air handling equipment, it can be divided into:

1, Centralized

2, Semi-centralized

3. According to the source of the treated air, it can be divided into:

1. Sealing ceremony

2, DC type

3. Mixed type (primary return air, secondary return air)

The main components of the equipment are: air conditioning host (cold and heat source), wind cabinet, fan coil unit and so on.

In essence, it is composed of three parts: air handling equipment, air conveying equipment, and air distribution device. In addition, there is a cooling system, a heating system and an automatic adjustment system.

Air Thermal and Humidity Treatment EquipmentAir thermal and humidity treatment equipment is mainly used to heat, humidify, cool, dehumidify and other treatments of air.

1) Water spray chamber. It is no longer used in civil buildings, but it is still widely used in air conditioners in textile mills and cigarette factories whose main purpose is to regulate humidity.

2) Surface heat exchanger. Coolers, heaters, and steam coils are collectively referred to as surface heat exchangers.

a. There are two types of coil surface heat exchangers: plain tube type and rib tube type. According to different processing methods, ribbed tubes can be divided into wound tubes, string tubes and rolled tubes.

In order to facilitate the use and maintenance, shut-off valves, check valves, filters, balance valves, pressure gauges and thermometers should be installed on the cold and hot coal pipelines. Steam regulating valves and traps are also installed on the steam lines of the steam heater. In order to ensure the normal operation of the surface heat exchanger, an air exhaust device (such as vertical and horizontal exhaust valves) should be set at the highest point of the water system, and a drain valve and a blowdown valve should be provided at the lowest point.

b. Electric heater. It has the advantages of compact structure, uniform heating, stable heat and convenient control. However, electric heaters use high-grade thermal energy, which is only suitable for use in some air conditioning units and small air conditioning systems. In large-scale air-conditioning systems with high requirements for constant temperature accuracy, electric heaters are also commonly used to control local heating or as final heating.

There are two types of electric heaters commonly used: bare wire type and tubular type.

In order to ensure safety, the following requirements must be met when designing and installing electric heating systems, especially when using bare wire electric heaters:

(1) The electric heater should be located in the air duct, and try not to put it in the air conditioner.

(2) The electric heater should be interlocked with the blower.

(3) The metal air duct where the electric heater is installed should be well grounded.

(4) The insulation materials of the air ducts within 0.8m before and after the electric heater shall be insulated non-combustible materials.

(5) The connecting flange between the air duct and the front and rear air ducts of the electric heater shall be lined with heat-resistant non-combustible materials.

(6) For the electric heater concealed in the air duct of the ceiling, a manhole should be opened on the ceiling relative to the position of the electric heater.

(7) An over-temperature protection device should be installed in the air duct behind the electric heater.

3) Commonly used air humidity treatment equipment.

Air humidification methods generally include water spray humidification (wet film humidification), high-pressure steam humidification, ultrasonic humidification, far-infrared humidification, etc. The mixing process of using a steam boiler to turn water into steam and air is an isothermal humidification process.

a. Isothermal humidification.

(1) Steam nozzle and dry steam nozzle.

(2) Dry steam humidifier.

(3) Electric humidifier.

b. Enthalpy humidification equipment. Humidifiers that spray water directly into the air in air-conditioned rooms include compressed air sprayers, electric sprayers, and ultrasonic humidifiers.

c. Humidification of the air.

(1) Refrigeration dehumidifier. It is more appropriate to use a refrigerated dehumidifier in a place where both humidification and heating are required. In places where there is a large amount of indoor humidity and heat, it is best not to use a refrigeration dehumidifier.

(2) Chlorination process rotary dehumidifier. Chlorinated rotary dehumidifiers use a special type of hygroscopic paper to absorb moisture from the air.

d. The most commonly used adsorbent in solid moisture absorption in air-conditioning engineering is silica gel.

After the silica gel loses its moisture absorption ability, it can be heated and regenerated, and the regenerated silica gel can still be reused.

Central air-conditioning system - the composition of the central air-conditioning system

1. Chiller:

This is the "refrigeration source" of the central air conditioner, and the circulating water leading to each room is "internally exchanged" by the chiller and cooled down to "cooling water".

2, Cooling water tower:

It is used to supply cooling water to chillers.

3. External heat exchange system:

Consists of two circulating water systems –

1) Chilled water circulation system

It is composed of a refrigeration pump and a chilled water pipe. The chilled water flowing out of the chiller is pressurized by the chiller pump and fed into the chilled water pipeline, and the heat exchange is carried out in each room, taking away the heat in the room, which is the temperature drop in the room.

2) Cooling water circulation system

It is composed of a cooling pump, a cooling water pipeline and a cooling tower. The chiller carries out heat exchange, which is the water temperature cooling at the same time, and a large amount of heat will be released. This heat is absorbed by the cooling water, which is the temperature of the cooling water increases. The cooling pump presses the heated cooling water into the cooling tower, where it exchanges heat with the atmosphere, and then sends the cooled cooling water back to the chiller. This continuous cycle takes away the heat released by the chiller.

4. Cooling fan:

There are two scenarios:

Indoor fans. It is installed in the room that needs to be cooled, and is used to blow the air cooled by chilled water into the room to accelerate the heat exchange in the room.

Cooling tower fans. It is used to reduce the water temperature of the cooling tower and accelerate the heat dissipation brought back by the "return water" into the atmosphere.

Central air-conditioning system - the dragging of the central air-conditioning system

1. Chiller dragging system

2. Refrigeration pump dragging system. It consists of several water pumps.

3. Cooling pump dragging system. It consists of several water pumps.

4. Drag system of fans (including indoor fans and cooling tower fans).

Central air-conditioning system - equipment analysis

1. The working principle of central air conditioning softened water equipment:

Since the hardness of water is mainly formed and represented by calcium and magnesium, cation exchange resin (water softener) is generally used to replace Ca2+ and Mg2+ (the main components of scale formation) in the water, and with the increase of Ca2+ and Mg2+ in the resin, the efficiency of resin in removing Ca2+ and Mg2+ gradually decreases.

When the resin absorbs a certain amount of calcium and magnesium ions, it must be regenerated, and the regeneration process is to rinse the resin layer with the salt water in the salt box, replace the hardness ions on the resin, and discharge the resin out of the tank with the regenerated waste liquid, and the resin will resume the softening and exchange function.

Since the hardness of water is mainly formed by calcium and magnesium, the principle of sodium ion exchange softening treatment is to pass the raw water through the sodium cation exchange resin, so that the hardness components Ca2+ and Mg2+ in the water are exchanged with the Na+ in the resin, so as to adsorb Ca2+ and Mg2+ in the water and soften the water.

2. Process flow and brief introduction of central air-conditioning softened water equipment:

The operation process of the general control valve is: operation, backwashing, salt absorption, slow washing, salt tank replenishment, and positive washing.

There are five processes: work (sometimes called permeate water, the same below), backwashing, salt absorption (regeneration), slow flushing (displacement), and fast flushing. All processes of different water demineralized water plants are very similar, but there may be some additional processes due to differences in actual processes or the need for control. Any sodium-ion-exchange-based water demineralized water plant is developed on the basis of these five processes (where a fully automated water softener plant adds a brine reinjection process).

Backwashing: After working for a period of time, the equipment will intercept a lot of dirt brought by raw water on the upper part of the resin, and after removing these dirt, the ion exchange resin can be completely exposed, and the regeneration effect can be guaranteed.

Salt absorption (regeneration): that is, the process of injecting brine into the resin tank, the traditional equipment is to use a salt pump to inject the brine, and the automatic equipment is to use a special built-in ejector to suck the brine (as long as the water has a certain pressure).

Slow rinsing (displacement): The process of slowly rinsing all the salts in the resin with raw water at the same flow rate after the resin has been passed through the resin.

Quick rinsing: In order to thoroughly rinse the residual salt, the resin should be rinsed with raw water at a flow rate close to the actual work, and the final water of this process should be soft water that meets the standard.

3. Overview of central air-conditioning softened water equipment:

The automatic water softener equipment is gradually upgraded on the basis of the domestic mechanical water softening equipment, absorbing the characteristics of negative pressure salt suction and water replenishment of imported valves, integrating solenoid valves, plane multi-way valves, microcomputer controllers, salt suction jets, brine flow transmitters, Soft water flow transmitter and other components, all parts have been molded, the valve body material is made of high-strength engineering plastic injection molding, the valve adopts ceramic seal, the controller has adopted LCD screen Chinese humanized display and operation, especially the use of salt water flow transmitter and soft water flow transmitter, as long as the corresponding operating parameters are set according to the raw water hardness at the factory, the stable operation of the equipment can always be guaranteed, and the softened water quality and low salt consumption can be guaranteed.

4. Product features of central air conditioning softened water equipment:

1) The new microcomputer controller controls the equipment to automatically carry out the process of water supply, backwashing, salt absorption, regeneration, and positive washing, which can realize unmanned management.

2) The continuous and stable water supply can be automatically regenerated at regular intervals and constant flow rates to ensure the production of high-quality softened water.

3) Reasonable and compact structure, integrated exchange tank and control valve, saving installation space and further improving operation reliability.

4) The multi-functional brine system can automatically dissolve salt, absorb salt, and adjust the liquid level of salt solution to ensure reliable automatic regeneration.

5) The uniform water distribution system can provide a uniform water flow in the tank, ensure the efficient use of resin, and prevent the loss of resin.

6) Low energy consumption: the water volume of self-produced water is <3%, the salt consumption is < 100 g/mol, the power consumption is 10W~40W, and the power consumption is equivalent to 3% of the mechanical water softening equipment.

7) Flexible design and selection, optional time and flow control mode; One use and one backup, alternate regeneration; Double-tank continuous water supply and other operation modes.

5. Technical indicators and work requirements of central air-conditioning softened water equipment:

Inlet water pressure: 0.18~0.6Mpa

Operating temperature: 5~45°C

原水硬度：≦8mmol/L

Mode of operation: manual/automatic

出水硬度:≦0.03mmol/L

Regenerant: Nacl (large-particle industrial salt)

Playback method: Backflow playback

Exchanger: 001×7 strong acid cation exchange resin

Control mode: time/flow

Power supply: 220V/50Hz

6. Application range of central air conditioning softened water equipment:

Automatic water softener: It can be widely used in steam boilers, hot water boilers, exchangers, evaporative condensers, air conditioners, direct combustion engines and other systems to soften the make-up water. It can also be used for the treatment of domestic water in hotels, restaurants, office buildings, apartments and other domestic water, as well as the treatment of softened water in food, beverage, wine, laundry, printing and dyeing, chemical, pharmaceutical and other industries.