Less refrigerant used

Here is claim:

Quote:

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10.1.1 Specific features
(1) Less refrigerant charge amount due to use of double phase refrigerant flow system. The total refrigerant charge amount has been
reduced by more than 50%.

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That is MHI Comercial series Heat pump non-inverter air-conditioner ceiling recessed type single split system
And here is refrigerant diagram:

http://farm4.static.flickr.com/3636/...bf8990_o_d.png

Could someone explain how this works and what is function of these marked parts in this refrigeration circle in both heating and cooling mode, since I found it difficult to understand?

And this is another variance:

http://farm4.static.flickr.com/3540/...da173f_o_d.png

I guess in cooling mode part2 is for oil return from accumulator.
Part 1 is for "flash gas+ liquid" injection in suction line if discharge temp. (thermistor Th-d) becomes too high.
Part 3 is to increase sub cooling. In this case after the capillary tube we have less capacity decrease.
Part 4 is used in heating mode to prevent outdoor heat exchanger frosting (thermistor Tho-R)
P.S. All above is IMHO

Quote:

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Originally Posted by narkom

I guess in cooling mode part2 is for oil return from accumulator.
Part 1 is for "flash gas+ liquid" injection in suction line if discharge temp. (thermistor Th-d) becomes too high.
Part 3 is to increase sub cooling. In this case after the capillary tube we have less capacity decrease.
Part 4 is used in heating mode to prevent outdoor heat exchanger frosting (thermistor Tho-R)
P.S. All above is IMHO

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Ok, thanks. That seams explain function of parts, but I am eager to know how is achieved that 50% less refrigerant in system.

Is it really like this? Have you compared the refrigerant charge with Daikin or ME units charge for the same capacity?

Quote:

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Originally Posted by narkom

Is it really like this? Have you compared the refrigerant charge with Daikin or ME units charge for the same capacity?

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1,1 kg of R22 for heat pump of 5,7kW cooling capacity.

Bare in mind that this is model from 2000 year or earlier.
Same size and year Fujitsu 1,7kg of R22.

ME charges 2.2 kg for heat pump of 5.4kW.
I guess MHI with 1.1 kg has minimum sub cooling in condenser. Note that they give only 20m height difference for 208 and 258 units.
ME gives 40m.
So no miracle at all))

Quote:

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Originally Posted by narkom

ME charges 2.2 kg for heat pump of 5.4kW.
I guess MHI with 1.1 kg has minimum sub cooling in condenser. Note that they give only 20m height difference for 208 and 258 units.
ME gives 40m.
So no miracle at all))

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You don't telling me that ME comes already charged for 40m?;)

ME has a large suction accumulator and comes already charged for 30 m.
MHI is charged for 5 m.
Concerning "double phase refrigerant flow'
I read that the
condensed high pressure refrigerant is reduced in pressure by the capillary tubes in the outdoor unit. This results in a “two-
phase refrigerant” of reduced pressure in the liquid section of the piping. The density of this two-phase refrigerant is 1/3~
1/2 of that of the high pressure liquid refrigerant, and thus is required in smaller amounts . As a result,
the length of the piping can be extended further, and the effects of height differences are reduced.

Quote:

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Originally Posted by narkom

ME has a large suction accumulator and comes already charged for 30 m.
MHI is charged for 5 m.
Concerning "double phase refrigerant flow'
I read that the
condensed high pressure refrigerant is reduced in pressure by the capillary tubes in the outdoor unit. This results in a “two-
phase refrigerant” of reduced pressure in the liquid section of the piping. The density of this two-phase refrigerant is 1/3~
1/2 of that of the high pressure liquid refrigerant, and thus is required in smaller amounts . As a result,
the length of the piping can be extended further, and the effects of height differences are reduced.

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From what i see in these diagrams that is different only in heating mode, in comparison with regular units, since in cooling mode, regular units also have two phase flow.

Do you have ME refrigerant diagram of simmilar unit for comparison?

Quote:

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Originally Posted by nike123

Do you have ME refrigerant diagram of simmilar unit for comparison?

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http://www.mrslim.com/UploadedFiles/...C%20PUH-EK.pdf
The same circulation system.

Quote:

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Originally Posted by narkom

http://www.mrslim.com/UploadedFiles/...C%20PUH-EK.pdf
The same circulation system.

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Thanks Narkom! It is same principle.

Here I see bypass valve. What is its purpose here?