Pressure enthalpy chart calculator9/2/2023 You may have even seen a pressure-enthalpy diagram before.Ĭharts like the one above show how changes in enthalpy correspond to changes in pressure throughout the system. In HVAC/R, we use enthalpy measurement to come up with the total heat change in a fluid, whether it's refrigerant, water, or air. Like most things, the scientific definition is as clear as mud. It's just a state function that depends only on the prevailing equilibrium state identified by the system's internal energy, pressure, and volume. (Note that the first few pressure values are in Vacuum inches in Hg.Enthalpy is easy. If you are working on an R-12 machine you are going to need to know your pressures. Most of these are through antique car collectors but there are other applications out there as well. Now, there are still some R-12 applications out there today. R-12 was banned in new automobiles and was replaced with by the HFC refrigerant we all know today as R-134a. At this point in time, in the early 1990’s, R-12 had seen the majority of it’s usage in automobile air conditioning. One of the first refrigerants to go was our friend R-12. The treaty aimed at phasing out all of these Ozone damaging refrigerants. Eventually a hole developed which caused the world to band together and create a global treaty known as the Montreal Protocol. This broken down chlorine would chip away at what’s known as the Ozone layer. In here the sun’s ultraviolet rays would break down the chlorine. You see if these refrigerants were vented into the atmosphere either through damage, mistake, or malfeasance the chlorine in these refrigerants would make its way up into the Stratosphere. It was in the 1980’s that a team of scientists discovered that these refrigerants did have a downside… and it was a big one. The world was being filled with CFC and HCFC refrigerants. So did the related refrigerants known as R-11, R-22, R-502 and many others. Its explosive growth continued over the years. Not more then thirty years later and you could find R-12 all over the world in all kinds of different applications. Only shortly after their invention these new refrigerants began to take the world by storm. It was during this partnership that we began to see the rise of artificial refrigerant classifications known as CFCs and HCFCs. Regardless of why these natural refrigerants weren’t working it was clear that the market needed a different kind of refrigerant. Sometimes it was flammability, toxicity, or operating pressure. All of the previous refrigerants like ammonia, propane, isobutane, and even carbon dioxide all had their own problems. It was in the 1930’s that the DuPont corporation teamed up with General Motors to come up with a safe, reliable, and cheap refrigerant. You see, R-12 is a CFC refrigerant and was one of the first artificially created refrigerants to see widespread usage. Even if you are not part of the industry chances are you have heard of R-12. R-12 is one of those classic refrigerants that nearly everyone has heard of before. This article aims at providing you with just that information. It will never fail that one of the first questions the pros ask the rookie is what is your subcool and what is your superheat? Having and understanding these numbers is key to figuring out what to do next.īut, these numbers won’t do you any good if you don’t know what refrigerant you are dealing with and what the refrigerant’s boiling point is at each pressure level. It doesn’t matter if you’re in Miami or in Fargo. I have heard stories of rookie techs calling some of the pros on their team for help on a system that they’re stuck on. It just becomes second nature after enough calls. Having these facts along with the saturation point, the subcool, and the superheat numbers for the refrigerant you are working on are essential when it comes to really understanding what is going wrong with your system.Īfter a visual inspection the very next step for the most seasoned technicians is pulling out their gauges and checking the pressure and temperature. One of the very first steps when it comes to diagnosing your home air conditioner, refrigerator, or even your vehicle’s air conditioner is understanding the temperature and the current pressure that your system is operating at.
0 Comments
Leave a Reply.AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |