I wrote a device handler for the Zigbee based eCozy Thermostats produced in Germany (http://ecozy.de/en). These thermostats / TRVs use the Zigbee HA profile and integrate quite well into SmartThings.
With this device handler you can pair the eCozy thermostats directly with the ST hub without the need of the eCozy Central Unit. Although the Central Unit does have some nice features and using the Smartphone App gives you a nice UI to configure things, a ST integration allows you to integrate eCozy into your home automation. One useful use case for me was that I can use external window sensors to control the thermostat when a window opens or closes. The eCozy thermostats have an integrated “Open Window” feature. But, in my case they didn’t sense the open windows unless I opened them totally wide and I wanted them to stop heating even if my window is open a little bit.
So, I hope you enjoy my device handler. This only pairs to the hub and gives a few settings (Celsius/Fahrenheit, Display locking and temperature calibration from -2.5 to +2.5 degrees correction). I will also code a SmartApp that adds the ability to load heating schedules into the thermostat as well as grouping them in rooms and merge settings across those thermostats. I will also add the external window sensor capability that is a bit limited in the current standard automation in ST (e.g. I would like to keep a manually set heat set point instead of a static definition that will overwrite my previous manual change or the ability to automate based on groups of sensors, for instance as long as one sensor is open keep all thermostats in the room off etc.).
But for now, here is the device handler.