I wish…Blender could render without the model being open. It takes up ram being open when it could be allocating it to the rendering. And yes, I have 96 gigs of ram. But I have a rendering going right that is using 92 gigs with the model open. In the rendering window, it says peak memory 30,593 MB. So at the most, I guess that means the rendering is only needing 30 GB of ram? I am almost in a jam here. If I could close the model, I could save about 20 gigs of ram space. Command line rendering is a pain plus there is no preview.
It seems like you have to use command line rendering, how else could you render the scene without opening Blender.
Try this script.
My suggestion is…Open Blender, send the rendering…Close Blender. Render continues with a preview. Similar to how Maxwell Render works. Maxwell opens a separate application to handle the renderings once they are sent from the main application.
I remember discussing this with some other Blender peeps on Twitter once. The conclusion we all came to is that somebody should write an addon that mimics this functionality (essentially, saving a copy of the .blend, then calling a new Blender instance from the command line to render it). And that writing this addon shouldn’t be difficult.
Nobody has since made this addon though. 
I think there was something like that from a japanese guy, it´s called scramble addon, man this was a huge addon and many things of it are now implemented in Blender.
There was this panel called background rendering, I think this should do what you guys expect.
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―(“Properties” Area > “Render” Tab > “Render” Panel)
[LIST] -
―(Background Rendering)
[LIST] - ―(Renders current blend file from command line)
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