Closed loop heating system selection requirements for refrigeration oil
Closed-circulation heating system is a certain requirement for refrigerating oil due to different occasions and refrigerants during use. What should LwanA closed-loop heating system pay attention to when selecting refrigerating oil?
Closed cycle heating systems such as chemical stability and oxidation resistance, moisture and mechanical impurities, and insulation properties. The flash point of a refrigerating oil is the temperature at which the lubricating oil is heated to the point where it ignites when it comes into contact with the flame. The flash point of the refrigerating oil used in the closed loop heating system must be 15 to 30 ° C higher than the exhaust gas temperature to avoid burning and coking of the lubricating oil.
The closed loop heating system oil temperature is generally maintained between 45 and 60 ° C. If the oil temperature has been unstable and slowly rising, it indicates a fault. If the oil temperature is too low or too high, it will deteriorate the lubricating oil. At the same time, it often indicates the arrival of the fault. The key to the pressure of the refrigerating oil is the difference in oil pressure. The oil pump does not oil because of various reasons, that is, the oil pressure difference cannot be established. The oil pressure depends on the structure of the compressor.
The requirement of the refrigeration oil of the closed cycle heating system is that the temperature at which the frozen oil is cooled to stop flowing under the experimental conditions is called the freezing point according to factors such as freezing point and viscosity. The freezing point of the refrigerating oil used in the closed loop heating system should be as low as possible (such as R22 compressor, the refrigerating oil should be below -55 °C), otherwise it will affect the flow of the refrigerant and increase the flow resistance, resulting in poor heat transfer. s consequence.
An important parameter in the characteristics of the refrigeration oil viscosity of closed-circuit heating systems. Different refrigerants should be used to select different refrigerants. If the viscosity of the frozen oil is too large, the mechanical friction power, friction heat and starting torque will increase. On the other hand, if the viscosity is too small, the desired oil film cannot be formed between the moving parts, so that the desired lubrication and cooling effect cannot be achieved.
The closed cloud heating system has a cloud point of the frozen oil. When the temperature is lowered to a certain value, the temperature at which the paraffin starts to precipitate in the frozen oil and the lubricating oil becomes turbid. The cloud point of the refrigeration oil used in the closed loop heating system should be lower than the evaporation temperature of the refrigerant, otherwise it will cause the throttle valve to block or affect the heat transfer performance.
Different closed-loop heating system manufacturers have their own requirements for the selection of refrigeration oil. Users can choose the corresponding refrigeration oil according to their working conditions and models.