Hot Gas By-pass

larry_16

Just need a reveiw why do you use hot gas by-pass on a chiller?

Empire_2

Bypass

In some applications it is used to unload the compressor. In affect it cuts it capacity by a given percentage. Example as the load in the chiller barrel aproaches it set point the by pass will be energised dumping the hot gas vapor into the suction line thus raising the suction pressure cutting its capacity by just a-little. Since the suction pressure increases to maintain a constant pressure or not allow the suction to get to lo. It all depends on what you want to do with it. Some hot gas bypass is used for defrost. Usually in lo tenp refrigeration.

It's been a while, I hope this helped. Eugeen can clairify.

larry_16

thanks

Thanks Mike that's what I thought it was for but couldn't remember when I was asked I know hot gas in a low temp refigeration system is for defrost but I don't deal with it much outside that applacation. Anyway, the solenoid is energized the whole time the unit is calling for cooling so I think it is for capacity

Eugene Silberstein 3

Mike is Right

Capacity control and to prevent the chiller barrel from freezing.

Empire_2

One additional note

You said that the solenoid is energised the whole time. Depending what solenoid you have (wether is powered on temp drop or rise) It really should only bypass when the temps or pressure are getting lower. On a warm day, the compressor should be fully loaded until temps drop. It loads, unloads loads unloads.... Not that fast but I think you get the picture.

larry_16

right mike

It does have a cpacity control after the solenoid and that is why it is energize when running. We were just looking at it today. I have a new guy working with me and he was asking me about it, then thinking about it, and getting the conformation made me relize what was going on. Sometimes it hard to jump back and forth too. Right now I am still thinking mostly about heating, not cooling at this time of year.

Thanks again for all your help guys,

larry