Charge compensator alternative

[reds007]

Hi,

does anyone know of alternative to using a charge compensator for heat pumps?

[Brian_UK]

Correctly sized accumulator?

[Magoo]

Can your please clarify what is actually a charge compensator.

[Brian_UK]

Can your please clarify what is actually a charge compensator.

I had to do some reading up myself

Copied from an Emerson bulletin---
http://www.hvacrinfo.com/cope_ae_bulletins/TAE1331.PDF

Charge compensator's: Charge compensator's are devices that store excess refrigerant during
the heating operation of a heat pump with a TXV refrigerant control.

Unlike an orifice, a TXV will not allow excess refrigerant to flood back to the compressor. This means that the excess system refrigerant will either have to back up in the indoor coil during heating, causing high head pressure, or be stored in a charge compensator until needed.

A charge compensator is normally a hollow vessel with only one opening that is attached to the vapor line. The shell is usually attached to the outdoor coil or has a line from the outdoor coil running through it for extra cooling during heating and to drive the refrigerant out during A/C operation. Again the size is dependent on how much refrigerant has to be removed from the system throughout the system operating map.

One point that is often overlooked is that this vessel contains liquid under fairly high pressure during heating. At the beginning of defrost, as the vapor line becomes the suction line leading directly into the compressor, most of the liquid refrigerant from the charge compensator is dumped directly into the compressor shell. Considering many hundreds of defrost cycles, this might have an adverse effect on the compressor.

A better design would be a charge compensator that can meter refrigerant back to the compressor at an acceptable rate. This design could take the form of a standpipe inside the
compensator with a small liquid return orifice at its base. A passing criteria for this design would be a compressor bottom shell temperature at least 5°F (2.7°C) warmer than the suction line or saturated suction pressure.

[Grizzly]

Brian.
I have learned some more today.

Thanks for the info.

Grizzly

[Magoo]

Thanks Brian, good research and reply