Direct Statement Of The Compressor
Direct statement demands the use of refrigerants with a boiling point sufficiently low to provide desired temperature in the evaporator. At the same time, refrigerants must be sealed at a reasonable pressure of the ambient air or water at normal temperatures. These requirements limit the lowest temperature that can be reached by direct the staging method. Practical lower limit of temperature is approximately 130F (90C) with the use of R-22, R-507, and from -90F (-68C) with R-717 (ammonia). The temperature cascade staging is usually required.
Intercoolers Intercoolers are devices used in the direct setting of the system to decrease the saturation temperature and pressure liquid refrigerant leaving the condenser and the suction of the steam entering the higher stage of the compressor. In any of the refrigeration process, refrigerant vapor is supeAeated during the compression process. With the direct production of cooling (cooling) of the refrigerant vapor between the stages of compression is necessary to avoid overheating higher stage compressors.
If the refrigerant vapor is not cooled before entering the next stage of compression, an excessive temperature will result, increases with each subsequent stage.
Large temperature differential between the last stage of the capacitor and the first-stage evaporator also leads to a significant flashes on the account device. Cooling liquid refrigerant between stages reduces these heavy losses in the cooling effect and tlie spacer accompanying increase in the volume of vapor diat must be processed low levels. Three types of coolers used in direct formulation of the design of the system are described below.
Three common methods of refrigerant vapour suction and cooling of liquid refrigerant in the direct development of systems. This type of device is called an open or flash intercooler, because the high temperature of the refrigerant from the higher stage condenser mixtures with a low temperature of the steam from the first stage of the compressor. This mixture reduces the temperature of the liquid inside tlie spacer measuring device, as some of the hot liquid flashes saturation temperature corresponding to the intercooler pressure. EC reset vapor low steps also desuper-sharp, as the bubbles through the saturated liquid intercooler. Saturated suction pair of first-booster) stage compressor is mixed with the flashed steam in the intercooler before flowing into the second stage of the compressor. These processes reduce cooling loss in the efficiency and throughput experienced by a phased compressor systems. Speed pair of open type intercooling, should not exceed 200 feet (61 m/min). Spacious area of separation is in the intercooler to ensure proper segregation of pairs of liquid drops, preventing the loss of fluid in the higher stage of the compressor.
Some of the advantages of open type intercooler are its simplicity, low cost and ability to reduce the temperature of the liquid refrigerant to saturation temperature corresponding to die interstage pressure. The refrigerating effect has been consumed in the coolant interstage temperature is economically higher stage suction pressure than it would be at a lower level of suction pressure, further improve the overall efficiency of the system. Therefore, the cooling fluid in the intercooler, reduces the power on ton, and the volume of requirements to low levels. The main disadvantage of this type intercooler-diat that reduces the pressure of the liquid at the inlet of the metering device intermediate pressure. This differential pressure requires that the dosing valve be too large to be able to pass enough liquid in the bottom of the differential pressure. This strategy reduces the efficiency, the metering device to change the overheating of the evaporator. Another disadvantage of this design is that the low temperature, low pressure of the fluid leaving the intercooler cannot be hypothermia. Therefore, there is a tendency, at which the fluid flash in the liquid line between the intercooler and the evaporator. For this reason, in the liquid line size with a minimal pressure drop...