Unfortunately, replacing R-22 in a large refrigeration system with an HFC substitute won't be easy... at least not a slam dunk. Depending upon your choice, you will need to one or more of the following: (1) replace the refrigerant oil with POE; (2) replace flow controls; (3) add compressor...
Perhaps one of my better publications, which happens to list popular refrigerants and their ASHRAE 34 safety group classifications. :-) http://www.sporlan.com/5-162.htm
The orifice equation should get you close:
m = Cf * A * (2 * gc * rho * deltaP)^0.5
where:
m = mass flow rate, lbm/sec
Cf = flow coefficient, 0.61 is appropriate for a flat plate orifice
A = orifice area, ft2
gc = gravitational conversion factor, 32.174 lbm-ft/lbf-sec2
rho = density, lbm/ft3...
You should have no problems with water hammer with the many step motor operated EEVs that are available. Pulsing solenoid valve type EEVs, however, can create water hammer if the conditions are correct as would any standard solenoid valve.
jpthiede, I'll assume evap temp (in/out) and cond temp (in/out) are air temperatures across the coil. With sample #2, are you comparing system operation at a 69°F ambient less the Articmaster, and 94.3°F with the ArticMaster? If so, the sample #2 numbers aren't particularly useful for...
My humble java psych calculator will properly handle "negative" altitudes within reason: http://members.socket.net/~aschoen/psychcalc.html.
Unfortunately with PMTHERM, altitude is selected from a combo box, and -1000 ft is the lowest value accepted. The psychrometric equations...
I'll assume you interested in suction line back to the compressor instead of the line from the low side receiver to the pump. You size the suction line using your design evaporator loads, and not the refrigerant flow thru the overfeed coil. The recirc ratio influences coil rating, but you only...
Theory:
A molecule in a vortex has increased velocity. This increased velocity has to result in either a lower pressure and/or a lower temperature. This would mean that the refrigerant enters the expansion valve with a combination of lower temperature and/or lower pressure.
jpthiede, you might...
Reynold’s number is a ratio of inertial flow forces to viscous forces within the fluid. Among other things, it is an indicator if the fluid flow is laminar or turbulent. A Reynold’s number of 2000 or less indicates laminar flow. Fluid particles in laminar flow move in straight lines. A...
Regarding point #3 postulated by jpthiede and questioned by ClydeMule, does adding a receiver to a system increase condenser and/or system capacity? One could make a safe assumption that it could increase condenser capacity, particularly if the system has a marginal condenser to begin with. If...
I could buy into an argument that liquid line temperature would level off at some point when overcharging a system, provided you get floodback as a result. This would be expected with a system using a restrictor as an expansion device.
If the system used a TEV, however, one could expect it to...
Overcharging a system will increase condensing pressure and temperature, condenser TD, and subcooling, but it will not necessarily lower liquid temperature. Problem here is increased condenser temperature will typically outpace increased subcooling. I think you're confusing increased subcooling...
Might I suggest a Sporlan RCZE-3-GA? Not many R-410A TEV are being sold thru Sporlan authorized wholesalers as of yet, so they will not likely have them in stock.
The assignment of zero enthalpy on a psych chart or refrigerant thermodynamic chart is arbitrary, and usually has nothing to do with true zero enthalpy, i.e., no usefully energy in the substance.
Since we are ultimately concerned with delta-h in our calculations, it make no matter where the...
Lowering condensing temperature will both lower the enthalpy of refrigerant liquid, and the pressure ratio across the compressor unit increasing its efficiency, provided the TEV is sized to handle the lower condensing pressure.
For any system employing a TEV, one can expect some capacity and...
Connecting multiple DX coils to a single condensing unit is done frequently, and to both air conditioning and refrigeration systems. Refrigeration systems with multiple evaporators will normally employ eprs (evaporator pressure regulators) when it is desired to operate the coils at different...
