Specific factors affecting the cooling effect of air conditioning

Specific factors affecting the cooling effect of air conditioning

In the entire air conditioning and refrigeration system cycle process, the compressor plays a role in compressing and transporting refrigerant vapor and causing low pressure in the evaporator and high pressure in the condenser. It is the heart of the entire system; the throttle valve plays a role in the refrigerant. Throttling and pressure reduction effect and adjust the flow of refrigerant into the evaporator; the evaporator is a device that outputs cold capacity, the refrigerant absorbs the heat of the object to be cooled in the evaporator, so as to achieve the purpose of producing cold capacity; the condenser is the output Heat equipment, the heat absorbed from the evaporator and the heat converted from the work consumed by the compressor are taken away by the cooling medium in the condenser.

　　 The energy-saving management of air-conditioning is relatively weak, and energy waste is more serious. Only when operating in the best working conditions and conditions can the maximum cooling capacity of the air-conditioning be used to achieve the purpose of energy-saving air-conditioning.

Among the four major components of air conditioners, the compressor efficiency has been determined by the investment cost. Therefore, what are the specific factors that affect the cooling effect of air conditioners? Today, the editor of okmarts.com will analyze and analyze with you, and provide you with corresponding solutions. reference:

　　 One, the evaporation temperature of the refrigeration system

The refrigerant absorbs heat and evaporates into gas, which is sucked by the compressor, so that the pressure of the evaporator will not increase due to too much heated vaporized gas, which will increase the evaporation temperature, which will affect the cooling effect, and this temperature difference , Is combined with the investment cost of the air conditioner (to reduce the temperature difference, the circulating air volume of the air conditioner must be increased, and the evaporator of the air conditioner must be increased, resulting in an increase in the cost of the air conditioner), and the energy consumption cost during refrigeration work. In the computer room air conditioner, the evaporator adopts the direct evaporation type, and the temperature difference is 12～14℃. In fact, due to the influence of various undesirable factors, this temperature difference cannot be guaranteed. Sometimes it is above 20°C (ice on the evaporator), which increases energy consumption. Through calculation, when the condensing temperature is constant, the lower the evaporating temperature, the lower the cooling effect of the compressor and the higher the exhaust temperature. The refrigerant in the evaporator in the refrigeration system reduces its evaporation temperature by 1 degree. To produce the same cold capacity, the power consumption increases by about 4%.

　　 2. Wrong opening degree of expansion valve

　　 It is necessary to regularly measure the superheat of the expansion valve and adjust the opening degree of the expansion valve. Proceed as follows:

　　 1. Shut down. Insert the probe of the digital thermometer into the insulation layer at the return air port of the evaporator, ready to read the temperature T1 of the return air of the evaporator. Connect the pressure gauge to the tee of the low pressure valve of the compressor (air conditioners without low pressure valve such as HIROSS40UA, connect the pressure gauge to the connector on the evaporator), prepare to read the temperature T2 corresponding to the outlet pressure of the evaporator.

　　2. Turn on the compressor, let the compressor run for more than 15 minutes, and enter the normal operation state, so that the system pressure and temperature reach a constant value. The high-pressure pressure measured on site is 18Kg/cm2, and the high-pressure switch is always in the closed operation state, so it has little impact on the system and is not used for special treatment.

　　3. Read the temperature T2 corresponding to the evaporator outlet temperature T1 and the evaporator outlet pressure. The degree of superheat is the difference between the two readings. Note that these two readings must be read at the same time, because the expansion valve is a mechanical structure, and its action will cause changes in T1 and T2 at the same time.

　　4. The superheat of the expansion valve should be between 5-8℃, if not, adjust it.

　　 Specific adjustment steps:

　　①Remove the protective cover of the expansion valve;

② Rotate the adjusting screw 2 to 4 turns; (expansion valves of professional air conditioners generally adopt the pressure rod type and the loose gear type. The loose gear type uses a small gear to drive a large gear. The number of adjustment turns is relatively large. Generally, it can be adjusted. 2~4 turns; the number of adjustable turns of the pressure rod type is relatively small, 1/4 turn each time; the expansion valve of the O65 air conditioner adopts a loose gear type).

　　③After waiting for 10 minutes, measure the superheat again to see if it is within the normal range. If not, repeat the above operation. The adjustment process must be careful. (If the oil blockage of the expansion valve is serious, clean it with absolute ethanol, and then reinstall it; the expansion valve that has lost its regulating function should be replaced; when replacing, pay attention to the installation position and heat preservation).

　　 3. Condensing pressure of refrigeration system

　　 1. The air conditioner condenser is dirty

Computer room air conditioners generally use air-cooled condensers, which are composed of multiple sets of coils, and fins are added to the coils to increase the heat transfer area on the air side. At the same time, fans are used to accelerate the air flow to increase the heat transfer on the air side. effect. Due to the small distance between the fins and the continuous use of the air conditioner in the computer room for a long time, flying insects and dust stick to the condenser fins, so that the air cannot flow through the condenser in a large amount, and the thermal resistance increases, which affects the heat transfer effect and causes the condensation effect Decrease, the pressure on the high-pressure side increases, and the refrigeration effect is reduced, while more power is consumed. For every 1kg/cm2 increase in condensing pressure, power consumption increases by 6-8%.

Countermeasure: According to the environment of the air conditioner, according to the ash formation, the external unit of the air conditioner should be flushed regularly. The specific method is to flush the air conditioner condenser from the inside to the outside with a water gun or compressed air, and remove the debris and dust attached to the condenser. Hangzhou Telecom Branch flushes the outside units of the air conditioner in the computer room twice a year to ensure good heat dissipation and save a lot of energy.

　　2. Improper condenser configuration

Some refrigeration equipment companies are pursuing profitability and deliberately deploying small condensers to reduce the cooling effect of the air conditioner. This situation should be avoided during the air conditioner design. However, sometimes it may cause frequent high-pressure alarms of the air conditioner in summer and frequent flushing of the air conditioner outside It is of no avail, seriously increasing the workload of maintenance personnel.

　　Countermeasure: The fundamental solution is to replace a suitable condenser.

　　 3. There is air in the system

　　 If the air conditioner is not sufficiently vacuumed, the air will be mixed in when adding liquid carelessly. Air is harmful in the refrigeration system. It will affect the condensation and heat release of the refrigeration agent's steam, which will increase the working pressure of the condenser. For example, the condensation temperature at the time is 35 degrees, and the corresponding condensation pressure is 12.5kg/cm2 gauge pressure. , But the actual pressure of the pressure gauge may be 14kg/cm2, this extra 1.5kg/cm2 of air is occupied in the condenser (Dalton's law), due to the increase in the exhaust pressure, the exhaust temperature also increases, and the cooling capacity Reduce, increase power consumption, so the air in the high-voltage system must be removed.

　　Countermeasure: Perform air release operation. In the case of shutdown, vent the air from the exhaust port or the condenser plug for air venting.

　　Through the above means, the air conditioner can be ensured to work in the best condition, which not only reduces the failure rate of the air conditioner, but also can save 10% to 20% of energy in summer.