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Oil Flow Design for a Sanden TRSE07 with oil separator

microHydro on Mon November 22, 2010 5:30 PM User is offline

When sizing the piping for a system using a Sanden TRSE07 with oil separator, do I need to consider minimum velocities to move oil through the system, or does the oil separator eliminate this restriction?

NickD on Tue November 23, 2010 9:05 AM User is offline gives the design information for test data. Scrolls have the advantage of being pistonless not requiring oil for the wobble nor piston rings, so the scroll can be bypassed, only the armature bearings require oil, too back that can't seal those off with a separate oil reservoir, thus the system wouldn't even to recirculate useless oil.

Always a better way to doing stuff. Already done in a good two stage vacuum pump also using a vane type pump, technology already exists. Compressor has fittings to be matched up with the tubing, pretty well determined for you, unless you plan on using adapters.

ice-n-tropics on Tue November 23, 2010 1:53 PM User is offline

The TR w/ internally integrated separator has a OCR (oil circulation ratio = oil weight/(ref wt + oil wt)) reduced from 3% varying up to 8% (W/o sep) to approx 1.5% (w/sep).
Internally (in and out of the crankcase) the OCR is the same w/ or w/o sep.
Note that Jacob shows a calorimeter on page 9 and 11 which calculates BTU & COP based on refrigerant mass flow w/ properties in and out of evap and compares result to within 5% with psychometric air side properties and condensed water in and out of the evap. This is referred to as a Secondary Calorimeter by ASHRAE and IMACA.

Nick, Thanks for posted attachment. The fixed and orbiting scrolls have rubbing /scuffing contact as their flanks touch/contact and require lube at their interface.
Oil traps in the plumbing are a negative, even w/ oil sep.
PAG separates from ref in the low pressure/ cold components of the A/C system, not much at higher temps.
Plumbing dia becomes more important in the plumbing between the evap out and the comp in to maintain a high enough velocity to carry most of the separated oil back to the comp in.

Yote Slayer, note page 16 concerning nuisance hunting (unstable refrigerant mass flow) with a IVD when the TXV is oversized (or not cross charged). IVD low displacement needs refrigerant expansion flow control equivalent to a small system or else the TXV will hammer between totally closed and relatively wide open and louver temps which spike 25 deg or more.
A cross charged TXV has 2 different refrigerants pushing on the diaphragm and results in no superheat at low displacement and normal superheat at max displacement of the IVD. This prevents dangerous low oil return during long term operation at minimum displacement. With a OT system oil return is not a problem.

Isentropic Efficiency=Ratio of Theoretical Compression Energy/Actual Energy. How To Air Condition Your Hot Rod

Edited: Tue November 23, 2010 at 1:55 PM by ice-n-tropics

microHydro on Tue November 23, 2010 2:52 PM User is offline

Thanks for your knowledge. It's cool to see that you both studied the bayyouk Sanden presentation. I had thought that its data might help me better understand the operating point for a TRSE07. It's too bad that they didn't attach their raw data.

Nick: I'll need to adapt my piping to the TRSE compressor. It looks like I can buy a model 4918 or 4919. What is the fitting called which adapts to either of those compressors? How would your recommend adapting them to copper tubing?

hotRodAc: So I'll need to design the piping for oil circulation at a 1.5% OCR. Does the OCR give me an oil charge volume? What is IVD?

ice-n-tropics on Tue November 23, 2010 7:00 PM User is offline

OCR doesn't give oil charge volume because additional oil hides in the crankcase and cold surfaces and oil traps
IVD = internally controlled variable displacement vs. external control (electronically via PWM.)


Isentropic Efficiency=Ratio of Theoretical Compression Energy/Actual Energy. How To Air Condition Your Hot Rod

NickD on Wed November 24, 2010 6:40 AM User is offline

If the compressor is mounted on the engine, refrigerant neoprene hoses are used, what I meant by an adapter is either to go to a larger or smaller size tubing, but not that many size choices in refrigeration. Tim can make your hoses or you can buy a crimping kit.

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