Briefly describe the composition of a compression chiller and its working principle

The gas compressed by the compressor is first placed in the condenser.

is cooled to the cooling water.

or air) to release heat, and then flow through the recuperator to be further cooled by the reflux gas, and enter the expander adiabatic expansion, the pressure and temperature of the compressed gas drop at the same time. When the gas expands in the expander, it does external work and becomes part of the input work of the compressor.

At the same time, the expanded gas enters the cold box and absorbs the heat of the cooled object, that is, to achieve the purpose of refrigeration. After that, the gas flows back through the heat recuperator, exchanges heat with the compressed gas, and then enters the compressor to be compressed.

1. The composition of the compressor refrigerator.

The compressor refrigerator is a refrigeration unit that uses the characteristics of endothermic evaporation and exothermic condensation of refrigerant to realize through compressors and other devices. It is mainly composed of compressors, condensers, expansion valves and evaporators.

Second, the working principle of the compressor refrigerator.

The working principle of the compressor chiller is to use the state change of the refrigerant in different environments to complete endothermic evaporation and exothermic condensation, so as to achieve the purpose of temperature reduction.

1.Compressor.

The compressor is the core part of the compressor chiller, and its function is to compress the low-pressure refrigerant into a high-pressure refrigerant, and increase the evaporation temperature of the refrigerant, so that the refrigerant takes away more heat when it evaporates. Common compressors include piston compressors, screw compressors and centrifugal compressors.

2.Condenser.

The condenser is another important component in a compressor chiller. Its function is to dissipate heat from the high-temperature and high-pressure refrigerant, make it condense into a liquid state, and discharge the heat out of the machine through radiators and other means. Common condensers include air condensers and water-cooled condensers.

3.Expansion valves.

Expansion valves are a critical part of controlling the flow of refrigerant. Its function is to flow the high-pressure refrigerant into the low-pressure area through the orifice, so that the pressure of the refrigerant is reduced, and the temperature is reduced. Common expansion valves include thermal expansion valves and electric expansion valves.

4.Evaporator.

The evaporator is the last component of the compressor chiller. Its function is to evaporate the refrigerant at low pressure, thereby absorbing the surrounding heat and achieving the refrigeration effect. Common evaporators include air-cooled evaporators and water-cooled evaporators.

3. Advantages and disadvantages of compressor refrigerators.

The advantages of compressor chillers are good refrigeration effect and large cooling capacity. However, its disadvantage is that the loss of refrigerant is large, and the noise and resonance phenomena generated during operation are also obvious. In addition, the maintenance and maintenance of compressor chillers is more complex and requires professional technicians to operate.

According to its principle, compressors can be divided into volumetric compressor and speed compressor.

The volumetric type is divided into: to Sui Qiaoshan duplex compressor, rotary compressor; Speed compressors are divided into: axial compressors, centrifugal widening and shrinking machines.

and mixed-flow compressors. ——Tilingte compressor.

The steam compressor is the key equipment for the thermal system to increase the temperature and pressure of the steam generated by compression. The function is to pressurize and heat up the low-pressure (or low-temperature) steam to achieve the temperature and pressure requirements required by the process or engineering. The overall composition of the steam compressor is relatively complex, mainly composed of three basic units: compression system, steam cooler and lubrication system.

The steam generated in the reboiler (evaporator) is passed through an embedded droplet separator to remove part of the liquid from the steam before entering the steam compressor or the corresponding steam consumption point. The process can be designed with an uncompressed steam bypass to automatically control the production requirements for different vapor pressures and temperatures or to prevent maintenance in the event of a compressor failure.

2. Compression system.

The compression form of the steam compressor is a single-stage centrifugal compressor driven by an integral gear unit, depending on the principle. According to different needs, the form of compressor is also different, and the common ones are roots compressor (positive displacement type), centrifugal compressor (speed type), etc.

3. Steam cooler.

The steam cooler is a specially designed nozzle that is installed in the **steam pipe. Vapor in flow atomizes as much water as possible into steam. The flow of water to the cooler is controlled by the temperature of the steam behind the cooler.

4. Lubrication system.

The lubrication system consists of an oil tank, two parallel water-cooled coolers, a set of parallel oil filters, and two oil pumps. The main oil pump is a progressive cavity pump that is driven directly by a low-speed gear shaft. The standby oil pump is driven by a motor and is used at start-up.

An oil cooler is a tubular heat exchanger in which oil flows. An oil mist eliminator and an electric heater are installed on the oil tank, and the lubricating oil is pumped from the oil tank to the gearbox through the oil cooler and oil filter, and the temperature of the oil is regulated by the temperature controller of the oil cooler bypass. There is a differential pressure indicator on the oil filter to detect contaminants in the filter.

5. Steam compressor form.

Depending on the direction in which the fluid passes through the steam compressor impeller, the equipment in question is referred to as an axial, mixed-flow, or centrifugal compressor. The most suitable compressor type depends on the operating conditions of the application. The key parameters are the temperature rise that needs to be achieved and the flow rate of the steam to be compressed.

Among the various refrigeration methods, compression refrigeration is the most commonly used, accounting for more than 90%. The principle of compression refrigeration is to use a refrigerant (a substance) to boil and absorb heat at low temperatures, because the temperature during boiling and heat absorption is lower than the temperature of the refrigeration object, the heat of the refrigeration object is transferred to the refrigerant, and the temperature of the refrigeration object is reduced. The compressor does work to increase the temperature and pressure of the refrigerant after heat absorption (higher than the ambient temperature).

At this point, the refrigerant can transfer heat to the environment. Then, by throttling and depressurizing, the refrigerant is boiled again at low temperatures to absorb heat. Constant cycle refrigeration.

The basic components of the first section of the vapor compression refrigeratorThe vapor compression refrigerator is composed of four main components: compressor, evaporator, condenser and throttle valve. These components are connected into a closed circuit through pipelines, in which the refrigeration working fluid-refrigerant circulates and continuously changes the state, so as to achieve the purpose of refrigeration. The compressor is a machine that inputs energy from the outside to complete the compression of the refrigerant from low pressure to high pressure, and is divided into piston type, centrifugal type, screw type, rotary type and other types according to its structure type and working principle.

The book has at the bottom of page 112

According to the principle of refrigeration and compression, the root oak can be divided into: volume type and speed type. （）

a.That's right. b.Mistake.

Correct Answer: a

1. The working principle of the piston compressor: The piston compressor is one of the earliest compressor designs, but it is still the most versatile and very efficient compressor. The piston compressor moves the piston forward in the cylinder through the connecting rod and crankshaft.

If only one side of the piston is used for compression, it is called a single-acting type. If both the upper and lower sides of the piston are used, it is called a double-acting type. Piston compressors are very versatile.

It can compress air or gas with little to no changes. Piston compressors are the only designs capable of compressing air and gases to high pressures for applications such as breathing air compressors. Configurations of piston compressors can range from single-cylinder configurations for low-pressure, small-volume applications, to multi-stage configurations capable of compression to very high pressures.

In a multistage compressor, the air is compressed in stages, increasing the pressure step by step.

2. The working principle of the rotary screw type patting air compressor: the rod air compressor belongs to the positive displacement compressor, and its piston adopts the form of a screw; This is the most predominant type of compressor used today. The main components of the screw compression element are the convex rotor and the concave rotor, which move close to each other, so that the volume between them and in the cavity gradually decreases.

The pressure ratio of the screw type depends on the length and shape of the screw and the shape of the exhaust port. The screw element is not equipped with any valves, and there are no mechanical forces that create an imbalance. As a result, it is possible to operate at high shaft speeds and to accommodate both high flow rates and small external dimensions.

3. The working principle of rotary sliding vane air compressor. Sliding vane compressors are driven directly at very low speeds (1450 rpm) using traditional, proven technology and offer unmatched reliability. The rotor is the only continuously running component with several slots cut along the length with sliding vanes that slide across the oil film.