Screw refrigeration compressor unit
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Some discussions on screw refrigeration compressors: 1) Let’s talk about the throttle valve first. Why does the refrigerant cool down as it passes through the throttle valve, while its pressure also decreases? As pressure decreases, the boiling point also decreases. A lower boiling point inevitably leads to the vaporization of the refrigerant, and vaporization is an endothermic process; heat absorption necessarily results in an increase in temperature. Therefore, a decrease in pressure must lead to an increase in temperature – how is it possible to have both a decrease in pressure and a decrease in temperature at the same time (given the relationship between temperature and pressure for the refrigerant)? It is understandable that the medium’s pressure is reduced by the valve, due to the resistance exerted by the valve; but as for the cooling effect, it’s not easy to understand how a valve can cool something. Is it called a cooling valve?
The concept of throttling should lead to the introduction of another concept, namely the vaporization rate after throttling; another related concept is the subcooling of the fluid before/after throttling. For example, what would be the pressure difference during throttling when room-temperature water is at saturation conditions before and after throttling? lol
You mean that the pressure of the refrigerant decreases as it passes through the throttle valve; vaporization is an endothermic process, and during this process heat is absorbed from the cooling water, so the problem with the cooling water is resolved
Let’s raise the second question first to avoid forgetting it: 2) Are the principles behind screw refrigeration compressors (including ice makers and brine makers) the same as those of air conditioners and refrigerators, namely the Carnot cycle or the reverse Carnot cycle?
Third question: 3) To what extent should the pressure and temperature after the throttle expansion valve be reduced? During normal operation, if ice forms at the compressor inlet, does this indicate that the process parameters are not properly controlled, resulting in a waste of cooling capacity?
Fourth question: 4) Is the entire unit, as a closed system, always in a saturated state with both gas and liquid present? That is, does it meet the pressure and temperature chart for saturated R22?
This post was last edited by jmdc on 2018-10-21 at 10:25. Fifth question: 5) (Taking the ice maker in our workshop as an example), the high-pressure liquid refrigerant in the receiver is sprayed into the gas-liquid separator (the pressure inside the receiver should be higher than that inside the gas-liquid separator). Will vaporization occur due to this spraying, resulting in a decrease in the amount of refrigerant flowing from the bottom of the gas-liquid separator to the evaporator? Does this process (including the gas-liquid separator) cause some of the refrigerant to undergo a loop circulation? Why not remove the gas-liquid separator and connect the condenser directly to the evaporator?
How can you understand anything if you only talk about concepts without mentioning quantities? Assuming that a person with low income is considered poor and thus in need of **assistance**, receiving ****assistance means an increase in income; so how can such a person still be poor if their income has increased?
The entire system is sealed, so why do the levels of fluorine and oil decrease? What is the typical interval for adding fluorine and oil?