Central air conditioning can be divided into the following three main types.
1, the wind pipe system
Air pipe system to the transmission of air medium, the principle of large and large central air conditioning system, the principle of the same. It makes use of the outdoor unit to generate cold / heat, from the indoor return air (or return air and wind mixing) gamma cooling heat treatment, sending people to indoor eliminate the air conditioning cold / heat load.
Compared with other domestic small central air conditioning type, the initial investment of the wind pipe system is small. If the fresh air, the air quality can be greatly improved. But the air transmission and distribution system of the air pipe system occupies a larger space in the building, generally requires a larger storey. And it uses a unified way of sending wind, in the absence of the end of the variable air volume, it is difficult to meet the different room air conditioning load requirements. And the end of the variable air volume will make the initial investment in the entire air-conditioning system greatly increased.
2, cold / hot water unit
The conveying medium of the cold and hot water unit is usually water or glycol solution. It through the outdoor host produce air conditioning cold / hot water, by piping system conveying to the interior of the terminal device, in the terminal device of the cold / hot water and indoor air for heat exchange, produce cold / hot air, thereby eliminating the cooling load of the air-conditioning room. It is a kind of air conditioning system which produces cold and heat, but it is dispersed to handle the load of each room.
The indoor terminal device of the system is usually a fan coil unit. Currently fan coil generally can regulate the rotating speed of the fan (or through the bypass valve adjustment after the amount of water in the coil), so as to adjust the supply of indoor cold / heat, so the system can of air-conditioned rooms each were individually adjusted and meet the needs of the various rooms of different air conditioning, and the energy saving is also good. In addition, due to the cold / hot water unit of the transmission and distribution system is very small, it is generally not limited by the height of residential. However, such systems are generally difficult to introduce fresh air, so the air conditioned room is usually closed, its poor comfort.
3, VRV system
Variable refrigerant flow (VariedRefrigerantVolume (VRV) air conditioning system is a kind of refrigerant air conditioning system, it with refrigerant for conveying media, outdoor host by the lateral compartment heat exchanger, compressor and other refrigeration accessories, terminal device is formed by direct evaporation type changing heat exchanger and the fan of the indoor machine. An outdoor machine can transport the refrigerant liquid to a plurality of indoor units through a pipeline. By controlling the compressor circulating mass of refrigerant and into the interior of the change of the refrigerant flow heat exchanger can be timely to meet the indoor cold and heat load requirements of the VRV system with energy-saving, comfortable, stable operation and other advantages, and each room can be adjusted independently, can meet the needs of different rooms for different air conditioning load. But the system control is complex, the material, manufacturing process, welding and other aspects of the requirements are very high, and the initial investment is relatively high.
Cleaning of condenser tube of central air conditioner:
In general, not by the processing unit because of scale, corrosion, pollution, mainly bring negative influence to the whole refrigeration system:
1) reduces the heat transfer effect of the condenser, which leads to the increase of the pressure in the pipe, the motor current of the compressor is increased, the running time is prolonged, and the power consumption is increased significantly.
2) can not give full play to the role of cooling water, increase water consumption.
3) due to the rising of the temperature of the exhaust temperature, a part of the oil vaporization, continue to boost the safety of the circulatory system.
The refrigeration world authoritative scientific body PhilipKotz show that central air-conditioning condenser dirt, scale directly reduce the heat exchange rate and the cooling capacity, condensing tube as long as there is the existence of 0.3 mm thick scale, will lead to heat exchange loss of 21%; there is 0.6 mm thick scale heat transfer losses amounted to 34 per cent; 0.9 mm thick scale existing heat loss of 44%. Cooling capacity decreased sharply, and the current load increased. In order to avoid unnecessary losses, it is very necessary and timely to clean the central air conditioning system.
The status quo: the current domestic cleaning technology is relatively backward, can not solve the power problems caused by scale, dirt from the root. Domestic cleaning methods mainly for the human and chemical treatment. The human is with rod and cleaning brush in the condenser, the scale and dirt off. This cleaning method can only be a temporary solution to the problem, with central air-conditioning to restart, new scale and dirt and immediately, and will of the pipeline caused by wear and tear. Chemical treatment is to discharge and add medicament to inhibit scale based and use most of the scaling characteristics of acid soluble to transformed into soluble salt, adding a certain amount of corrosion inhibitor. Keep cleaning liquid repeatedly to insoluble in acid salts of scour and make it fall off, in order to cleaning. And the cleaning method of the biggest problem is that, due to the complexity of the composition and structure, especially for long-term accumulated to completely remove the difficulty and cost are not very high. In addition, emissions and additive effect is limited, after a period of time nevertheless to be shutdown for maintenance. The cleaning methods can only delay and reduce the scale formation rate, with the passage of time, scale will eventually form.