Refrigeration
After the liquid refrigerant absorbs the heat of the object being cooled in the evaporator, it vaporizes into high-temperature and low-pressure steam, which is sucked into the compressor, compressed into high-pressure and high-temperature steam, and then discharged into the condenser. In the condenser, it flows to the cooling medium (water or air). ) releases heat, condenses into high-pressure liquid, is throttled into low-pressure and low-temperature refrigerant by the throttle valve, and then enters the evaporator again to absorb heat and vaporize, achieving the purpose of cycle refrigeration. In this way, the refrigerant completes a refrigeration cycle through the four basic processes of evaporation, compression, condensation, and throttling in the system.
The main components are compressor, condenser, evaporator, expansion valve (or capillary tube, subcooling control valve), four-way valve, compound valve, one-way valve, solenoid valve, pressure switch, fuse plug, output pressure regulating valve, pressure It consists of controller, liquid storage tank, heat exchanger, collector, filter, dryer, automatic switch, stop valve, liquid injection plug and other components.
electric
The main components include motors (for compressors, fans, etc.), operating switches, electromagnetic contactors, interlocking relays, overcurrent relays, thermal overcurrent relays, temperature regulators, humidity regulators, and temperature switches (defrosting, preventing freezing etc.). Composed of compressor crankcase heater, water cutoff relay, computer board and other components.
control
It consists of multiple control devices, which are:
Refrigerant controller: expansion valve, capillary tube, etc.
Refrigerant circuit controller: four-way valve, one-way valve, compound valve, solenoid valve.
Refrigerant pressure controller: pressure switch, output pressure regulating valve, pressure controller.
Motor protector: overcurrent relay, thermal overcurrent relay, temperature relay.
Temperature regulator: temperature position regulator, temperature proportional regulator.
Humidity regulator: Humidity position regulator.
Defrost controller: defrost temperature switch, defrost time relay, various temperature switches.
Cooling water control: water cutoff relay, water volume regulating valve, water pump, etc.
Alarm control: over-temperature alarm, over-humidity alarm, under-voltage alarm, fire alarm, smoke alarm, etc.
Other controls: indoor fan speed controller, outdoor fan speed controller, etc.
refrigerant
CF2Cl2
Freon 12 (CF2Cl2) code R12. Freon 12 is a colorless, odorless, transparent and almost non-toxic refrigerant, but when the content exceeds 80% in the air, it can cause suffocation. Freon 12 will not burn or explode. When it comes into contact with an open flame or the temperature reaches above 400°C, it can decompose into hydrogen fluoride, hydrogen chloride and phosgene (COCl2) that are harmful to the human body. R12 is a widely used medium-temperature refrigerant, suitable for small and medium-sized refrigeration systems, such as refrigerators, freezers, etc. R12 can dissolve a variety of organic substances, so ordinary rubber gaskets (rings) cannot be used. Chloroprene elastomer or nitrile rubber sheets or sealing rings are usually used.
CHF2Cl
Freon 22 (CHF2Cl) code R22. R22 does not burn or explode. It is slightly more toxic than R12. Although its water solubility is greater than R12, it may still cause "ice jam" in the refrigeration system. R22 can partially dissolve with lubricating oil, and its solubility changes with the type and temperature of lubricating oil. Therefore, refrigeration systems using R22 must have oil return measures.
The corresponding evaporation temperature of R22 under standard atmospheric pressure is -40.8°C, the condensation pressure does not exceed 15.68×105 Pa at normal temperature, and the cooling capacity per unit volume is more than 60% greater than that of R12. In air conditioning equipment, R22 refrigerant is mostly used.
CHF2F3
Tetrafluoroethane R134a (ch2fcf3) code R13 is a non-toxic, non-polluting and safest refrigerant. TLV 1000pm, GWP 1300. Widely used in refrigeration equipment. Especially in instruments with high refrigerant requirements.
type
steam condenser
This kind of condensation of steam condenser is often used to condense the final secondary steam of the multi-effect evaporator to ensure the vacuum degree of the final effect evaporator. Example (1) In a spray condenser, cold water is sprayed in from the upper nozzle, and steam enters from the side inlet. The steam is condensed into water after full contact with the cold water. At the same time, it flows down the tube, and part of the non-condensable vapor may also be brought out. Example (2) In a packed condenser, the steam enters from the side tube and comes into contact with the cold water sprayed from above. The condenser is filled with porcelain ring packing. After the packing is wetted by water, the contact area between the cold water and the steam is increased. , the steam condenses into water and then flows out along the lower pipeline. The non-condensable gas is extracted from the upper pipeline by the vacuum pump to ensure a certain degree of vacuum in the condenser. Example (3) Spray plate or sieve plate condenser, the purpose is to increase the contact area between cold water and steam. The hybrid condenser has the advantages of simple structure, high heat transfer efficiency, and corrosion problems are relatively easy to solve.
Boiler condenser
Boiler condensers are also called flue gas condensers. The use of flue gas condensers in boilers can effectively save production costs, reduce the exhaust gas temperature of the boiler, and improve the thermal efficiency of the boiler. Make the boiler operation comply with national energy conservation and emission reduction standards.
Energy conservation and emission reduction are the key and guarantee for the transformation of the economic development model outlined in the national "Eleventh Five-Year Plan". It is an important symbol for implementing the scientific outlook on development and ensuring sound and rapid economic development. Special equipment, as a major energy consumer, is also a source of environmental pollution. Important sources, the task of strengthening energy conservation and emission reduction of special equipment has a long way to go. The Outline of the Eleventh Five-Year Plan for National Economic and Social Development established that reducing total energy consumption per unit of domestic production by about 20% and reducing total emissions of major pollutants by 10% are binding indicators for economic and social development. Boilers, known as the "heart" of industrial production, are a major consumer of energy in our country. High-efficiency special equipment mainly refers to heat exchange equipment in boilers and pressure vessels.
The "Boiler Energy Saving Technical Supervision and Management Regulations" (hereinafter referred to as the "Regulations") came into effect on December 1, 2010. It is also proposed that the boiler exhaust temperature should not be higher than 170°C, the thermal efficiency of energy-saving gas boilers should reach more than 88%, and boilers that do not meet the energy efficiency indicators cannot be registered for use.
In a traditional boiler, after the fuel is burned in the boiler, the exhaust gas temperature is relatively high, and the water vapor in the flue gas is still in the gaseous state, which will take away a large amount of heat. Among all types of fossil fuels, natural gas has the highest hydrogen content, with a mass percentage of hydrogen of about 20% to 25%. Therefore, the exhaust smoke contains a large amount of water vapor. It is estimated that the amount of steam generated by burning 1 square meter of natural gas is The heat taken away by the paper is 4000KJ, which is about 10% of its high heat output.
The flue gas condensation waste heat recovery device uses lower temperature water or air to cool the flue gas to reduce the temperature of the flue gas. In the area close to the heat exchange surface, the water vapor in the flue gas condenses, and simultaneously realizes the release of the sensible heat of the flue gas and the latent heat of water vapor condensation. Release, and the water or air in the heat exchanger absorbs heat and is heated, realizing heat energy recovery and improving the thermal efficiency of the boiler.
The thermal efficiency of the boiler is improved: the theoretical flue gas volume produced by 1NM3 natural gas combustion is about 10.3NM3 (about 12.5KG). Taking the excess air coefficient of 1.3 as an example, the flue gas is 14NM3 (about 16.6KG). If the flue gas temperature is reduced from 200 degrees Celsius to 70 degrees Celsius, the physical sensible heat released is about 1600KJ, the water vapor condensation rate is taken to be 50%, and the latent heat of vaporization released is about 1850KJ. The total heat release is 3450KJ, which is about 10% of the low-level calorific value of natural gas. If it is taken as 80 % flue gas enters the heat energy recovery device, which can increase the heat energy utilization rate by more than 8% and save nearly 10% of natural gas fuel.
Split layout, various installation forms, flexible and reliable.
As the heating surface, the spiral fin tube has high heat exchange efficiency, sufficient heating surface, and small negative force on the flue gas side system, which meets the requirements of ordinary burners.
risk factors
