EMB145 captain reported on climb out with one air conditioning pack deferred; the other pack failed....

Narrative:

Aircraft had MEL of pack 2. While climbing out pack 1 valve closed (advisory message) and would not remain open after following QRH procedures; rendering us with no air conditioning or pressurization systems found by searching the EICAS for cabin altitude climb rate. We contacted ATC; stopped the climb approximately FL180; started a descent; and started a return to ZZZ. In troubleshooting the problem; pack 2 was able to provide pressurization and cooling during our descent as temperatures in cockpit and cabin were high. Utilized pack 2 although it was MEL. During the logbook review; the pack was MEL because of the valve closing; and a reason why I attempted to operate it and see if it would assist us in our situation. Due to the quick action of the flight crew; the cabin altitude was never out of tolerances and the only discomfort was temperature for passengers and the delay; as we were down to ten thousand feet very quickly. CRM was a great part; as the entire crew was able to return the aircraft safely to the ground in minimal time.

Original NASA ASRS Text

Title: EMB145 Captain reported on climb out with one air conditioning pack deferred; the other pack failed. Captain reported crew ran QRH procedure and used deferred pack to provide pressurization and cooling on return to departure airport.

Narrative: Aircraft had MEL of Pack 2. While climbing out Pack 1 valve closed (advisory message) and would not remain open after following QRH procedures; rendering us with no air conditioning or pressurization systems found by searching the EICAS for cabin altitude climb rate. We contacted ATC; stopped the climb approximately FL180; started a descent; and started a return to ZZZ. In troubleshooting the problem; Pack 2 was able to provide pressurization and cooling during our descent as temperatures in cockpit and cabin were high. Utilized Pack 2 although it was MEL. During the logbook review; the Pack was MEL because of the valve closing; and a reason why I attempted to operate it and see if it would assist us in our situation. Due to the quick action of the flight crew; the cabin altitude was never out of tolerances and the only discomfort was temperature for passengers and the delay; as we were down to ten thousand feet very quickly. CRM was a great part; as the entire crew was able to return the aircraft safely to the ground in minimal time.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

Attributes
ACN	1478540
Time
Date	201709
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Aircraft 1
Make Model Name	EMB ERJ 145 ER/LR
Operating Under FAR Part	Part 121
Flight Phase	Climb
Flight Plan	IFR
Component
Aircraft Component	Air Conditioning and Pressurization Pack
Person 1
Function	Captain Pilot Not Flying
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Total 5000
Events
Anomaly	Aircraft Equipment Problem Less Severe Deviation - Procedural MEL

EMB145 captain reported on climb out with one air conditioning pack deferred; the other pack failed. Captain reported crew ran QRH procedure and used deferred pack to provide pressurization and cooling on return to departure airport.