Bitzer condenser

[ronaldo9]

Hi Guys

Wondering can anybody shed some light on a bitzer condensing unit I came across today. I didn't get much time at it so this was just a quick observation.

Bitzer condenser serving a small 3 to 5 degree coldroom. The condenser had some after market alterations. The condenser coil had a second coil mounted on the outside. A stat was set up on the discharge so when the condenser temp got too high a solenoid would bring this second coil into play.

Also the compressor was set up to constantly run. They welded a T piece into the liquid line. They fitted a solenoid to this that when energized would feed an TXV which was piped into the suction . So basically the compressor would constantly run but once the room was at temp it would just be spinning its wheels.

Like I said I didn't get much time with this.

What benefit would there be to having the compressor constantly running?
Why have the second condenser coil? This was done at install so it wasn't something fitted after the fact


Any ideas ?

Cheers

[Rob White]

.

2 things I think??

First if the 2nd condenser is on a solenoid (mag valve) is the mag valve on the inlet or the outlet of the cond?

It sounds like a bodge by somebody who had high pressure issues in the past and put this second Condenser on.

In the past I have bodged a water pipe feeding water spray into a cond to help in high ambient conditions but it
was a short term bodge until a new condenser could be ordered and installed (it lasted 5 years ).

The liquid injected into the suction?? Are you sure the comp is not on a LP switch pump-down cycle and the liquid injection to suction, is used for cooling?


Compressors don't like stopping and starting, in-fact most comps only have a maximum of 6 starts an hour.
There is a school of thought that keeping the compressor running 24 hours a day and then controlling the capacity is a lot more efficient than stopping and starting the compressor.

Horses for courses but in my experience single system systems on a LP pump-down cycle is normal.
Capacity control is better with multiple circuits or different operating temps.

Rob

.

[al]

It sounds like a stability chamber set up, hot gas injection when no cooling load to keep compressor running, is there humidity and temperature control in the room?