Low Evaporating Temp TXV

[nadeem.usmani]

How to set TXV temperature in Brazed Plate Heat Exchanger. I am assembling a chiler for water temperature of 34 degree F. The temperature range printed on TXV is from -49 to +50 F 

[Sandro Baptista]

What kind / brand is your TXV?

[nadeem.usmani]

It is Danfoss TEX2 for R22

[Sandro Baptista]

What's the evaporating temperature and superheating that is concern to the selection of the plate heat exchanger?

[nadeem.usmani]

The target Evaporating temperature is 35 F or 2 C. Not sure about superheat
What kind of design chanes required for different evaporating temperatur like very low temperature freezers for ice cream hardning

[Sandro Baptista]

The target Evaporating temperature is 35 F or 2 C. Not sure about superheat


Please inform about the inlet and outlet water temperature.

[nadeem.usmani]

Sorry for late reply The detail of the chiller is as following

It is a water chiller for a Bakery

Ref Capacity 10 ton
Tank Capacity 90 gal
Water Circulation 30 gal / min
Delta Temp 10 C
Required wter temp 2 C
Water Draw from tank 30 gal after every 20 miniuts

I think I have made a mista to ask you the design Evap temp of 2 C or 34 F. I think it should be some where minus 5 C (to achive 2 C water)

[chemi-cool]

What is the PHE capacity?
The TXV size has to fit that capacity regardless the evaporting temp. When you get this info, you can determine the condensing unit size, Or you can check your 10 ton refrigeration unit capacity at -5C and then work out the TXV size and PHE capacity at your required water flow and leaving temp.

Remember that water freezez at 0C so you might need to add some glycol but that will decrease the unit capacity.

[Sandro Baptista]

That's right chemi-cool. But you have to keep in mind that the "size" of the TXV is also affected by the evaporating temperature. Lowering the evaporating temperature less capacity it allows considering the same superheat.

[nadeem.usmani]

My basic question is still there
How to lower the evap temp setting of TXV
The way I understand the factory setting is @ 7 C
How to make it -5 C

[icecube51]

watch out for the low temps in your plate evap. remember the 4°C fase change of water!!

if yore flow is not strong enough.....sh...t will happen

Ice

[Sandro Baptista]

My basic question is still there
How to lower the evap temp setting of TXV
The way I understand the factory setting is @ 7 C
How to make it -5 C

Why do you say it came 7ºC. The valve adjust itsel to new dynamic conditions. The thing you can some how adjust is the superheat but even so it can vary depending of the moment liquid demand.