CoolSim 5.4.180 preview 12

The desktop build of October 19, 2026, with 11 changes. It is built on CoolSim 5.4.180.

Changed

Can make a model solve to a different answer than before.

The Room Editor no longer lifts turning-vane cooling units

In a room with no raised floor, every OK in the Room Editor raised each cooling unit with a turning vane by one more vane height, with no limit: on one of our test models, each OK put five units another 0.6 m (2 ft) off the floor. The preview raises a unit only if it or its vane would be below the floor, and only that far, so further OKs move nothing. A unit raised by an earlier build stays where it is: set its height in its editor.

The Room Editor re-fits the room on every OK

In CoolSim 5.4.180, OK in the Room Editor skipped the step that fits objects to a changed floor, ceiling or plenum and works out rack, server and PDU airflows again for a changed air density. On one of our test models, 107 racks kept airflows worked out for the old density, 10% off by mass; on another, two blocks stayed inside a plenum that had been removed. The preview runs that step on every OK, as CoolSim 5.4.177 did.

A typed air density reaches the solver

A room switched from altitude to a typed air density kept sending the density worked out from the altitude, with the altitude: one of our tests typed 1.1025 kg/m³ and sent 1.058 kg/m³ at 1,500 m. The preview sends the density you typed.

A Frontflow PDU stands on a solid floor

CoolSim lifts Upflow and Downflow PDUs 6 in off a solid floor. A PDU switched to Frontflow kept that lift and floated, and earlier previews lifted new Frontflow PDUs too. The PDU editor’s OK now takes the lift off and says so. A height you set to exactly 6 in yourself looks the same, so the message says how to put it back.

A cable cutout stays inside the room

A Start Point or Size typed past the room walls was sent where it was: one of our tests sent a cutout 305 m (1,000 ft) along a room 15 m (50 ft) long. The Cable Cutout editor’s OK now moves it inside, trims it if it is larger than the room, and says so.

Baffles placed by end points reach into a raised floor

In a raised-floor room, the baffle editor reset a negative End Point Y to 0, so a baffle placed by its end points could not go down into the supply plenum. With end points it now accepts down to the bottom of the plenum; with a size the lowest is still 0.

New

Run Simulation warns before a run would drop something

After the hidden-objects check, Run Simulation now warns when CRAC Parameter Variation will not run (a cooling unit is not on the Supply Temperature cooling method, or has both fan and coil off, so only the baseline case would solve), when perforated tiles are in a room with no raised floor (they would be sent as vents through the floor), and when a cable cutout saved earlier reaches past the room walls. Choose OK to run as it is, or Cancel to go back and change the model.

Preview 12 also comes in CoolSim 5.4's classic look

A second installer gives the same preview 12, with every change above, in CoolSim 5.4’s grey Windows style: its fonts, buttons, toolbar icons, splash screen and 3D view colors. Windows the previews rearranged keep their new layout in the old colors. Both install CoolSim 5.4 Preview, so installing one replaces the other.

Improved

The Room Editor says what it changed

In a room with no raised floor, OK removes a plain cooling unit’s plug fan, because there is no plenum for it to sit in. It did that without a word before; now a message names the unit. When raising a unit to stand its vane on the floor uses up its ceiling extension, the extension is removed and a message says so.

The Groups report counts every member

Group members whose names start with a digit or hold spaces or punctuation dropped out of the group’s totals in the report. The solve was not affected.

A PDU's plug fans follow its inlets and outlets

A PDU with plug fans gets one fan for each inlet or outlet you set in the editor. CoolSim 5.4.180 kept the count from before, so the 3D view could show more or fewer fans than openings. Plug fans are drawn in CoolSim only and do not change what is sent to the solver.

Something working differently?

Tell us your CoolSim version and what you did. We’ll tell you which change it is, and what it means for your model.

Ask about a change