Crib net resemble the mosquito net used at home, only crib Tent is meant for the babies and have a lot more functions than just a mosquito net.Baby mosquito net protect your child from mosquitoes and various insects both indoors and outdoors. Mosquitoes may carry threatening diseases, and a net may be the first line of defense between your child and a mosquito bite.
VALUABLE TEXTILE CO., LTD is a comprehensive modern enterprise integrating manufacturing and sales. Since its establishment in 2016, the company has risen rapidly in the Home Textile industry with its professional technical ability and mature craft production level. Valuable Textile Co., Ltd. is a manufacturer which focus on producing different kinds of indoor and outdoor mosquito nets,bed canopy, baby canopies, kid play tents. Every year, VALUABLE exported to over 20 countries and up to 2,000,000 pieces of products to the whole world.
Baby Mosquito Net,Baby Cot Netting,Crib Net,Stroller Net,Crib Tent Valuable Textile Co., Ltd. , https://www.valuablecanopies.com
Analysis of air conditioning design from compressor performance curve
In the refrigeration industry, the compressor has become the heart of the air conditioner. The design of the air conditioner is good or bad. The index of air conditioning performance can be achieved. The determination of the temperature of each key point of the air conditioning system is inseparable from the compressor. However, the performance of each manufacturer's compressors is different, and the effect is quite different. Therefore, as an air-conditioning designer, learn to see the compressor performance curve, is the most basic design entry lessons, today, the refrigeration express for everyone to analyze the performance curve of a variable-frequency dual-rotor compressor.
The compressor is a two-rotor DC inverter compressor. The compressor characteristics are 1: the minimum evaporation temperature of the press is -10 °C, and the transition period can be as low as -20 °C. This compressor is a high pressure chamber compressor.
Question 1: As shown in the figure, why is the low frequency phase a diagonal line, what is the problem?
Question 2: As shown in the figure, why is the high frequency stage a diagonal line, what is the problem?
Question 3: What are the reasons for limiting the minimum evaporation temperature?
Question 4: Why are the compressor exhaust temperatures required for different frequency platforms?
It can be seen from the characteristic diagram that this is not the specified operating range, but the characteristic graph. Since the DC inverter compressor is actually a speed regulating DC motor, it follows the law of the DC motor. Due to the physical properties of the refrigerant, the inverter compressor has an initial current (less than this current is only the start of the compressor, but does not reach the increased pressure), beyond which the compressor outlet pressure gradually increases. This period is a constant torque process (flat in the middle).
When the current (motor speed) reaches a certain value, the temperature is lowered by the evaporating temperature limit.
Limiting the evaporation temperature is not very easy, the characteristics of each compressor are limited, and the outlet parameters are constant.
In addition to the strength considerations, the operating range of the compressor mainly considers two factors: 1. Motor power and cooling of the motor to prevent the motor temperature from being too high; 2. For the compressor that supplies oil by differential pressure, the suction and exhaust pressure difference exists. Minimum limit.
Problem 1: In the low frequency phase, the compressor gas flow rate is low. If the pressure difference is higher than a certain value, the volumetric efficiency decreases, the displacement decreases, and the motor is insufficiently cooled, so it is necessary to limit the exhaust pressure;
Question 2: In the high-frequency phase, the motor power is mainly considered. The same evaporating temperature, the exhaust pressure and the high power are large, so it is necessary to limit the discharge pressure, and the discharge pressure is reduced as the rotational speed increases;
Problem 3: Limiting the evaporation temperature may also consider the cooling flow rate. The lower the evaporation temperature, the smaller the mass flow rate. Of course, the compressor's own evacuation capacity is also limited;
Question 4: For compressors that use a suction-cooled motor, the inspiratory point of the true elementary volume is after the motor, not the compressor suction port. At low frequencies, the refrigerant flows to the suction point after cooling the motor due to the small flow. The temperature is high and the exhaust gas is high, and the temperature of the suction port is the same. For such compressors, the exhaust gas temperature will be higher when the load is generally the same.
At the beginning of the general design, the scope of use will be limited and confirmed by testing. For high-pressure chamber compressors, if the exhaust gas temperature is too high, the lubricating oil will change color or even crack and carbonize. Generally, the oil temperature is 10~20 °C higher than the exhaust temperature. For high-pressure chamber compressors, the exhaust gas temperature is too high, which makes the motor easy to demagnetize.