Strange glycol loop behavior

[Miriam]

The primary (I haven't checked the secondary yet) glycol loop in the CSM behaves strange since about a month: evap out temp stays constantly at about 35°F, no matter what you do. You can even go to extremes and bypass the radiators while the evap is deactivated: it stays stubbornly at 35°. Even more interestingly, the other temps don't go over the top in this config, instead it settles down to about 75°F radiator inlet temp and seems to be happy with that -which is, from my rudimentary understanding of thermodynamics, impossible.

 

[n72.75]

Do you remember which version this started with? We will take a look at it.

 

[Miriam]

Unfortunately, no. But I have a feeling that it started this month, if thats any help...

 

[n72.75]

I made a fairly substantial systems update on November 2, which changed the way that vapor pressure and enthalpy of vaporization were calculated. But during testing I actually noted that the ECS glycol got a bit warmer on ascent. We flew 3 full missions before merging the update so I'm inclined to think that it was something later causing this. Our CSM ECS is not super accurate at the moment, with respect to the system drawings, unlike the LM. This will get a major update eventually.

 

[rcflyinghokie]

Yeah those glycol temps are just kind of cheaty right now, the CSM ECS is getting an overhaul but as long as I can remember that primary glycol temp has stayed around 35 or so. I wouldnt worry about it now as the overhaul should address this and many other issues.

 

[STS]

I made a fairly substantial systems update on November 2, which changed the way that vapor pressure and enthalpy of vaporization were calculated. But during testing I actually noted that the ECS glycol got a bit warmer on ascent. We flew 3 full missions before merging the update so I'm inclined to think that it was something later causing this. Our CSM ECS is not super accurate at the moment, with respect to the system drawings, unlike the LM. This will get a major update eventually.

Did I fly that on Apollo 7? I didn´t saw any strange behaviour on the ECS... Not sure I flew with the ECS update...

 

[n72.75]

Did I fly that on Apollo 7? I didn´t saw any strange behaviour on the ECS... Not sure I flew with the ECS update...

I think you were one version behind intentionally. Less bugs to find that way.