Node-Webkit is a desktop runtime for Windows, Mac and Linux. The newest release -- NW 0.11.X "includes" (or, "is based on") Chromium 38, which means that NW apps are fully Web Component compliant with no polyfills - including no need for webcomponents.js. There is no need to "install Polymer with Bower." Simply include
in your app's head and you are good to go -- just pull in any Polymer components you want to use, or create your own.
Node-webkit is an open source equivalent of Adobe Air, Sencha, TideKit, etc. It may suit your use-case, but be aware that it is a full runtime environment. It includes a complete node.js environment and a complete V8 javascript interpreter (a "browser in a box"). Even the smallest NW Desktop App will produce a ~50 MB stand-alone executable file, (or require the user to have Node-webkit installed).
It is a fantastic (and largely overlooked) Open Source project.
Jonathan Dodd ( Windows Desktop App Creation with node-webkit )