placed in front of the majority of the condenser tank cars, however, parts of heat, air conditioning system capable of the tube, a rapid manner, air in the vicinity of the tube spread. During the distillation, the liquid gas or vapor into the condenser apparatus is referred, however, all of the condensers of gas or vapor using heat carried away operation. Automotive condensers is a refrigerant into the evaporator, the pressure is reduced, the high pressure gas into low-pressure gas, a process to absorb heat, the evaporator surface temperature is low, then by a fan blowing cool air can be condensed out from the compressor is a high pressure, high temperature refrigerant, cooled to a high pressure, low temperature and then vaporized through the capillary tube, to an evaporator in the evaporator.
1. The types and characteristics of the condenser
Cooling medium condenser according to their different, can be divided into water-cooled, evaporated, air-cooled, water spray condenser four categories.
(a) water-cooled condenser
it is a water-cooled condenser as a cooling medium, water temperature away heat of condensation. Circulating cooling water is generally used, but the systemThe need to cool a cooling tower or the pool. Water-cooled condenser according to the different types of structures can be divided into a vertical shell and tube type, horizontal shell and tube water cooled condenser according to the different types of structures can be divided into a vertical shell and tube type, horizontal shell telescopic tube and other common shell and tube type condenser.
1, vertical shell and tube condenser
known as a vertical shell and tube condenser vertical condenser, water cooled condenser which is a currently widely used in ammonia refrigeration system . Vertical condenser mainly by the shell (barrel), tube sheet and tube bundle so on.
The refrigerant vapor from the steam inlet into the cylinder at a height of 2/3 of the gap between the bundle, the high temperature refrigerant vapor and an outer water cooling pipe inside the tube by heat exchange through the wall, so that the refrigerant steam is condensed to a liquid and gradually flows to the bottom of the condenser, the liquid outlet pipe flows into the reservoir. The endothermic water tank into the lower portion of the concrete, the water pump and then into the cooling tower through the cooled recycling.
To make the cooling water can be evenly distributed to each nozzle, the tank equipped with a condenser with a top plate and the water absorbed in the tube bundle with the upper portion of each nozzle with a deflector chute, so that the cooling water to the inner wall of the film-like layer of water flow down the pipe, both to improve the heat transfer and the effect of saving water. Further, the housing is also provided with a vertical condenser, pressure equalizing tube, pressure gauge, relief valve and vent pipe fittings and the like, so as to connect the respective lines and equipment.
The main features
vertical condenser is:
1. Since a large high velocity flow of cooling, so that a high heat transfer coefficient.
2. Vertical installation footprint, and it can be installed outdoors.
The cooling water flow and the flow rate through the large, so the requirement for water quality, water generally can be used as cooling water. The
4. The tube easy to remove scale, and the refrigeration system operates without stopping.
The coolant temperature rise in the vertical condenser but generally only 2 ~ 4 ℃, logarithmic mean temperature difference is generally about 5 ~ 6 ℃, so that a large amount of water. And since the device is placed in the air, the tubes susceptible to corrosion, leaks easily than found.
2, horizontal shell and tube condenser
horizontal vertical condenser with a condenser and housing structure similar, but there are many differences in general, mainly the difference is that the horizontal placement and multiple water flow housing. LieOutside the condenser tube ends of each plate with a closed end cap, casting a trap is designed interfitting ribs, the entire tube bundle is divided into several groups on the tube cap. So that the cooling water into the lower portion of the end cap, flows sequentially through each tube group, and finally flows out from the upper end cap of the same process, and from 4 to 10 to the return. Doing so can enhance the flow rate of cooling water in the pipe, thereby increasing the heat transfer coefficient, and also allows high temperature refrigerant vapor enters the heat exchange between sufficient cooling water tube bundle with the inner tube from an upper portion of the intake pipe housing.
The condensed liquid flows into the liquid outlet pipe from the lower portion of the reservoir tube. In another end to end of the condenser cover also has a permanent air vent and drain cocks. When the exhaust valve in the upper part, put into operation in the beginning of the condenser open to the air discharge cooling water pipe in the cooling water to flow unimpeded, remember not to be confused with the vent valve, so as to avoid accidents. Exhausted within the cooling water in the water when the faucet turn on the water for the condenser disabled, to avoid water freezing in winter due to the cracking condenser. Some remains the same as the intake system and other devices connected to the housing a horizontal condenser, a liquid equalizing pipe, vent pipe, valve, pressure gauge and discharge fittings and tubing fittings.
horizontal condensers are widely used not only to ammonia refrigeration system, freon refrigeration system can also be used, but its structure is slightly different. Horizontal ammonia condenser cooling pipe with smooth seamless steel pipe, and a cooling tube of the condenser is generally used freon horizontal low rib brass. This is due to the lower coefficient of heat because of freon. Notably, some freon refrigeration units generally does not have a reservoir tube, using only the bottom of the condenser is provided at least several rows of tubes, serving as the reservoir with the cylinder.
Horizontal and vertical condenser, in addition to the two different distribution and placement of water, the water temperature and the water are not the same. Vertical condenser cooling water along the inner wall downstream of gravity *, only a single stroke, so to obtain a sufficiently large heat transfer coefficient K, it is necessary to use large amounts of water. Horizontal and condenser with cooling water pump to the cooling pipe, it can be formed into a multi-line program condenser and the cooling water flow can be sufficiently large and the temperature rise (Delta; t = 4 ~ 6 ℃). Therefore, a small amount of horizontal condenser cooling water can be obtained a sufficiently large K values.
However, the flow rate is excessively increased, the heat transfer coefficient K value is increased little, while cooling water pump power consumption is significantly increased, the flow rate of the cooling water of the condenser the ammonia and generally horizontal about 1m / s for the should, Horizontal condenser cooling water flow rate of freon use 1.5 ~ 2m / s. Horizontal Condenser high heat transfer coefficient, a small amount of cooling water, compact structure, easy operation and management. However, the cooling requirements of good water quality, cleaning and scale inconvenient, but also difficult to find a leak.
The refrigerant vapor enters from above the cavity between the inner and outer tubes, the outer surface of the inner tube is condensed, the liquid bottom of the outer tube downstream turn, flows from the lower end of the reservoir. Cooling water enters the condenser from below, sequentially flows through the tube from an upper part of each row, and the refrigerant in countercurrent mode. Advantage
Such a condenser is the heat transfer coefficient of simple structure, easy to manufacture, and because the tube is single condensation medium opposite to the direction of flow, so the heat transfer effect, when the water flow rate of 1 ~ 2m / s when up 800kcal / (m2h ℃). The disadvantage is that large metal consumption, and when a large number of longitudinal tubes, a lower tube filled with more liquid, the heat transfer area can not be fully utilized. Further compactness difference, difficult to clean, and require a lot of connection elbow. Thus, this condenser has been rarely used in the ammonia refrigeration system.
(b) Evaporative Condenser
heat
evaporative condenser cooling water mainly in air evaporation and absorption of the latent heat of vaporization is performed. Press the air flow can be divided into a suction and pressure feed type. In this type of system relies on the cooling effect of the condenser further evaporation of the refrigerant in refrigeration systems to cool the generated refrigerant vapor of the heat transfer partition wall on the other side, which causes condensation liquefaction. Evaporative condenser consists of a cooling tube group, water supply equipment, ventilator, and the flap housing and other parts. Serpentine group seamless steel cooling pipe coils made of bent groups, packed in rectangular cabinets made of thin steel sheet.
has a top or sides of the box fan, cooling water circulation tank serving as the bottom housing. When working evaporative condenser, the refrigerant vapor from the upper portion into the serpentine group, the condensation heat in the tube and flows into the liquid outlet pipe from the lower reservoir. Cooling water from the circulating pump to the sprinkler, the spraying of the steering wheel from the surface of the tube group of serpentine coil group through the inner tube wall absorbed the heat of condensation to evaporate. Provided in the side or top of the box fan coil force air passing from bottom to top, to promote the evaporation of water and the water evaporated away.
wherein, when the fan is mounted on top of the tank, the suction side serpentine group located on the suction fan is referred evaporative condenser, And referred to as the wind turbine installation at both sides of the housing, the fan positioned serpentine group outflow-side pressure feed type evaporative condenser, the intake air uniformly through the serpentine group, so the heat transfer effect, but in the fan run under hot and humid conditions, failure-prone. Although pressure feed air through serpentine tube group is not uniform, but a good fan motor operating conditions. Characteristics
evaporative condensers:
1, as compared with the DC supply of water-cooled condenser, water savings of about 95%. However, when compared to water-cooled condenser and a cooling tower in combination with the water almost.
2, compared with the water-cooled condenser and cooling tower system combination, both almost condensation temperature, evaporative condenser but compact structure. With the air-cooled or water-cooled condenser DC supply compared to its relatively large size.
3, as compared with air-cooled condenser, which is low condensing temperature. Especially more pronounced in dry areas. Run throughout the year, the winter can be air-cooled work. Compared to the DC supply water-cooled condenser, the higher the condensation temperature.
4, condensing coil corrosive, easy to scale the outer tube, and difficult to maintain.
on the total, the main advantage of evaporative condenser water consumption is small, but the high temperature cycle, the condensing pressure, difficult to clean scale, strict requirements for water quality. Especially suitable for dry, dehydrated areas, should be in the open air circulation places to install, or installed on the roof, shall be installed indoors.
(c) air-cooled condenser
The air-cooled condenser as a cooling medium is air, the air temperature rise away the heat of condensation. This condenser is suitable for extremely dry or not the water supply situation, common in small Freon refrigeration unit. In such a condenser, the refrigerant discharged air heat is taken away. Air may be natural convection, the fan may also be used as a forced flow. Such a location for a condenser-based refrigeration apparatus freon inconvenience or difficulty in the water.
(iv) watering Condenser
composed mainly of heat exchange coil, leaching tank so on. The refrigerant vapor from the lower portion of the steam inlet into the heat exchange coil, the cooling water flows from the top of heat exchange coil slot leaching tank, into a film downwardly absorb condensation heat, water, natural convection of the air, Since the evaporation of water, the heat of condensation heat is carried away portion. The cooling water is heatedIt flows into the tank, and then recycled after cooling tower, or a portion of the water drain, and the additional portion of fresh water poured into the tank. The condensed liquid refrigerant flows into the liquid reservoir. Watering condenser water temperature is in the air and the water evaporated away the heat of condensation. Such condensers mainly for large and medium-sized ammonia refrigeration system. It can open-air installation can also be installed below the cooling tower, but avoid direct sunlight. The main advantages of the water spray condenser is:
1, simple structure, easy manufacture.
2, when the leakage of ammonia is easy to find, easy maintenance.
3, easy to clean.
4, low water quality requirements.
The disadvantages are:
1, the low heat transfer coefficient
2, high metal consumption
3, large area
2 condenser refrigeration principle
[123. ] in refrigeration systems, an evaporator, a condenser, a compressor and a throttle valve in the refrigeration system are the four essential elements, the general principles of the condenser cooling is sucked to the compressor from the evaporator of the lower pressure the refrigerant vapor, and then lower the vapor pressure of the compressor to a higher pressure of steam compression, the volume of the steam is reduced, the pressure increases, so that the pressure rises into a condenser, condensed in a condenser after the high pressure fluid into, the throttle valve after the throttle, becomes lower pressure fluid, and then into an evaporator, absorbing heat in the evaporator is evaporated into low-pressure steam, so as to achieve the refrigeration cycle.
1,
a vapor compression refrigeration principle
single-stage vapor compression refrigeration system, a refrigerant pressure isCompressor, condenser, evaporator and throttle four basic components. Sequentially connecting duct between them, form a closed system, refrigerant circulates continuously through the system, the state change, to exchange heat with the outside world. After the working process after the basic principle of the cooling system, the liquid refrigerant absorbs heat of the object to be cooled in the evaporator, the low-temperature low-pressure vaporized into steam, is sucked into the compressor, compressed into high-temperature high-pressure steam into a condenser, the condensed vessel to a cooling medium (water or air) heat, condensed into high pressure liquid, throttled to a low temperature and pressure through the throttle valve of the refrigerant entering the evaporator again absorbs heat of vaporization, the purpose of circulating refrigerant. Thus, the refrigerant in the system via evaporation, compression, condensation, expansion four basic processes a complete refrigeration cycle.
in refrigeration systems, an evaporator, a condenser, a compressor and a throttle valve in the refrigeration system are essential four pieces, which were cold evaporator is a conveyance device. In which the refrigerant absorbs the heat of the cooling object to effect cooling. Compressor is the heart, plays a suction, compression, transport refrigerant vapor action. Condenser heat is released device, the heat absorbed in the evaporator together with the heat transformed compressor work together to transfer the cooling medium taken away. Throttle refrigerant from throttling effect, while controlling and adjusting the amount of refrigerant flow into the evaporator liquid system is divided into two parts and the high pressure side and low pressure side. The actual cooling system, in addition to the above-described four pieces, often some auxiliary equipment, such as a solenoid valve, a dispenser, a dryer, collector, fusible plug, pressure controller and other components, which are running in order to improve economy, reliability, and security and settings.
2,
Main components constituting the cooling system
The air conditioner in condensed form can be divided into: two kinds of air-cooled and water-cooled, depending on the purpose can be divided into single-cold and cooling and heating type two, regardless of which type of configuration is a combination of the following main components made.
The main components of a refrigeration system has a compressor, a condenser, an evaporator, an expansion valve (or capillary, subcooling control valve), a four-way valve, double valve, check valves, solenoid valves, pressure switches, melting plug, the output of the pressure regulating valve, pressure controller, storage tank, a heat exchanger, collector, a filter, a dryer, an automatic opening and closing, valves, plugs, and other injection components.
The main components of the electrical system with a motor (compressor, a fan, etc.), operation switch, an electromagnetic contactor, chain relay, an overcurrent relay, the thermal overcurrent relay, a temperature controller, humidity control, temperature switches (except cream, and the like with preventing freezing). Compressor crankcase heater, water relays, computer boards, and other components.
by a control system composed of a plurality of control means :
- The refrigerant controller: expansion valve, a capillary tube.
The controller of the refrigerant circuit: the four-way valve, check valve, double valve, a solenoid valve.
The refrigerant pressure controller: a pressure opening and closing, the output of the pressure regulating valve, the pressure controller.
Motor protector: overcurrent Thermal over-current, temperature relay.
Temperature regulator: Temperature-position, temperature scale.
Humidifiers: Bit humidity regulator.
Defrost Controller: switching defrost temperature, the defrost relay, a variety of temperature switches.
Cooling water control: relay without water, water regulating valves, pumps and the like.
Control Alarm: over-temperature, super-wet, undervoltage and fire, smoke alarm.
Other control: indoor fan, the outdoor fan speed controller.