liquid overfeed system design guide

[US Iceman]

I forgot to ask a question lana. Why was this thread started in the hydrocarbon forum? Just curious.

Are you thinking of using a liquid overfeed system on a hydrocarbon system? That would be interesting, but no reason it could not be done.

[lana]

I forgot to ask a question lana. Why was this thread started in the hydrocarbon forum? Just curious.

Are you thinking of using a liquid overfeed system on a hydrocarbon system? That would be interesting, but no reason it could not be done.

Actually yes. I would like to know about liquid overfeed system with "*****".
As I mentioned, I maybe never ever use this system in real life but I must know how to design it .

Cheers

[lana]

I forgot to ask a question lana. Why was this thread started in the hydrocarbon forum? Just curious.

Are you thinking of using a liquid overfeed system on a hydrocarbon system? That would be interesting, but no reason it could not be done.

My mistake, sorry.
I meant Halocarbon "*****".

If necessary please change the section.

Thanks

[US Iceman]

If I understand you correctly, lets assume 4:1 circulation rate for the evaporators.

Why not give this a go on your own, and I'll watch what you do and comment when necessary.

This type of system was one of the hardest for me to figure out for the same reasons you were looking for a design guide.

The best way to learn, is to do... Answers fought for are remembered far longer than answers given.

[lana]

Why not give this a go on your own, and I'll watch what you do and comment when necessary.

This type of system was one of the hardest for me to figure out for the same reasons you were looking for a design guide.

The best way to learn, is to do... Answers fought for are remembered far longer than answers given.

HI,
I lost you there. What do I do?

[Josip]

Hi, Lana

This type of system was one of the hardest for me to figure out for the same reasons you were looking for a design guide.

The best way to learn, is to do... Answers fought for are remembered far longer than answers given.

-30°C/+35°C in one stage? It is possible but not too much economical

No subcooling of liquid entering into separator vessel!? What about economizer?

What about defrosting of evaporators?

You expect answers but here you have additional questions But...don't give up

Why not give this a go on your own, and I'll watch what you do and comment when necessary.

Best regards, Josip

[lana]

Hi Josip,

-30°C/+35°C in one stage? It is possible but not too much economical

I know, I just want to start from a simple system then complete it as I go ahead.

My first question is this : Do we have to select the compressor with capacity (200kW in this example), te=-40°C and tc=35°C? Or other parameters must be taken into account?
If the capacity is high for one compressor, then can we use parallel arrangement?

Thanks for comments.
Cheers

[Samarjit Sen]

We have just completed a project for an Ice Cream Hardening Room where the Room Temperature is being maintained at - 35 Deg. C. The refrigeration compressors being used are Dorin single stage semi hermetic compressor. We have installed DTC in both the compresssors. The refrigerant being used is R 22. We brought the Room Temperature down to - 40 Deg. C, but our client wanted to set the temperature at - 35 Deg. C. The capacity of each compressor is 12 kw at - 45 Deg C Te and 40 Deg C Tc.

The plants are running very well. The Evaporators are from Heatcraft Larkin.

The DTC system adopted is vapour injection to the compressor head.

This is just for information.

[Josip]

Hi, Lana

Hi Josip,

I know, I just want to start from a simple system then complete it as I go ahead.

My first question is this : Do we have to select the compressor with capacity (200kW in this example), te=-40°C and tc=35°C? Or other parameters must be taken into account?
If the capacity is high for one compressor, then can we use parallel arrangement?

Thanks for comments.
Cheers

All new projects are connected to requirements/wishes and ability to fulfill them and you as design engineer are in between. You just start to dance with the wolfs

Generally the capacity of compressor/s must be little above the required one but more important is to install good condenser (maybe with one heat exchanger for sanitary water) to obtain lower and constant condensing pressure.

Regarding the number of compressors I prefer always to install more units (screws for full load and piston for reduced load in parallel work) because we need to have spare compressor to obtain reliable work. It depends on type of plant.

An example: for continuous freezing tunnel we can provide one/two screws for full capacity (one is/can be standby, depending how important is to have freezing tunnel to run in any time), but with cold store is much better to use mixed compressors with different capacities i.e. the same compressor you can use for tunnel or for cold store but with possibility to switch the system.

In your case maybe is not bad idea to think about two stage system -40°C/-10°C (-40°F/14°F) first stage and -10°C/+35°C (14°F/95°F) the second stage with 3 compressors. One for first stage , one for second stage and one connected to both system we use to call this one Jolly.

This way is of course more expensive, but this is only one idea.

Let's see some other suggestions

Best regards, Josip