Some questions on 30GX-207 air cooled chillers

[abcxyz5]

Hi

I am quite new to this field and industry and currently handling this type of chiller.

We have daily recording on several parameters of the chillers and some of them are like :

1) Saturated suction pressure / temperature
2) Saturated discharge pressure / temperatuer
3) Discharge superheat
4) Motor temperature
5) Gas discharged temperature
6) Oil pressure
7) Oil differential pressure
8) Economizer Pressure

Ive tried to find what's the normal values or range that I should expect in normal operations in its manual but couldn't find one. Anyone knows where can I find them?


Secondly, what does the oil differential pressure means ?And what does it for?


thirdly, i tried to find what's the function of the economizer and how does it works. But couldnt find any resoruces expect at youtube by indians. But I cannot understand their language unfornately.

Thank you so much!

[seanf]

Hi

I am quite new to this field and industry and currently handling this type of chiller.

We have daily recording on several parameters of the chillers and some of them are like :

1) Saturated suction pressure / temperature
2) Saturated discharge pressure / temperatuer
3) Discharge superheat
4) Motor temperature
5) Gas discharged temperature
6) Oil pressure
7) Oil differential pressure
8) Economizer Pressure

Ive tried to find what's the normal values or range that I should expect in normal operations in its manual but couldn't find one. Anyone knows where can I find them?


Secondly, what does the oil differential pressure means ?And what does it for?


thirdly, i tried to find what's the function of the economizer and how does it works. But couldnt find any resoruces expect at youtube by indians. But I cannot understand their language unfornately.

Thank you so much!

Saturated suction temperature should be about 5-8 degC below the water/glycol outlet temperature.
Saturated discharge temperature should be about 8-15 degC above condenser air inlet temperature.
Discharge superheat could be anywhere between about 20K and 50K or even more.
Motor temperature, not sure.
Gas discharge temperature probably about 70 degC.
Oil pressure, not sure.
Oil differential pressure, not sure.
Economizer pressure, not sure.

The values vary depending on the cooling load, ambient temperature and what capacity the chiller is running at.

Oil differential pressure - is the amount of difference in pressure between the oil at two points in the oil circuit. Different manufactures use different reference point, like
(oil pressure at the outlet of the oil pump) - (compressor oil sump pressure)
or
(oil pressure before oil filter) - (oil pressure after oil filter)
ect...
The oil differential pressure is used as a safety device, so if theres a problem with the oil supply to the compressor its shut down.

The economizer - Its a heat exchanger used to cool further the liquid refrigerant that comes from the condenser, to try and increase the chillers efficiency. It uses some of the liquid refrigerant from the condenser outlet, to be used to cool the rest of the liquid refrigerant that gets sent to the main heat exchanger that chills the water/glycol.

Compressor economizer port - Is an inlet to the compressor, where the pressure is higher than the main suction pressure. It allows you to have three pressures in the system, the suction pressure, the economizer pressure, and discharge pressure.

[abcxyz5]

Hi

Thanks for your reply

1) I believe the outlet temperature is the leaving water temperature?

2) Is the condenser inlet equivalent to ambient temperature?

3) The values that you provide, is it average values over all compressors and system?

For example, if the leaving water temperature is 11.1 degC, system A SST is 11.1 and system B SST is 12.3, is the 5-8 degC the difference for each system with 5he LWT or the difference between LWT with average of the two system?

4) Does the value that you provide is applicable for all types of chillers?

[seanf]

Hi

Thanks for your reply

1) I believe the outlet temperature is the leaving water temperature?

2) Is the condenser inlet equivalent to ambient temperature?

3) The values that you provide, is it average values over all compressors and system?

For example, if the leaving water temperature is 11.1 degC, system A SST is 11.1 and system B SST is 12.3, is the 5-8 degC the difference for each system with 5he LWT or the difference between LWT with average of the two system?

4) Does the value that you provide is applicable for all types of chillers?

1. Yes the outlet temp is the leaving water temp.

2. Yes the condenser inlet is the temperature of the air being pulled into the condenser, normally the ambient temp.

3. If your chiller has two separate systems A and B, then look at each one individually for the refrigerant parameters.

Link to R134a pressure temperature chart -> https://www.fsw.uk.com/sites/www.fsw.uk.com/files/r134a-pressure_temperature_chart.pdf

The SST is the temperature the refrigerant boils at.
If you had a leaving water temp of +11.1 degC, youd probably see a SST of about +4 degC, for R134a that gives you a suction pressure of about 34psig.

eg.
Leaving water temperature: +11.1 degC
SST: +4 degC (equivalent pressure: 34psig)
Suction gas temp: +11.0 degC
Suction superheat: +7 degC

4. The values are roughly what you should expect to see for chiller that has an air cooled condenser and a DX (dry/direct expansion) type evaporator. The values are also roughly what you would see for most other air cooled, DX evaporator refrigeration system.