I have a customer who is thinking about correlating HVAC data in Splunk. They are also interested in correlating weather data and access card readers to correlate employee traffic and weather with energy usage. Anyone done this before?
Most of the apps you will find will be "IT oriented" I doubt you'll find prebuilt things for this use case. But at the end of the day, Splunk is just a database, you can fill it with any data you want as long as you can retrieve them. If for example your sensors write their output in a file, then it's super easy to import them and start building dashboards. If they have REST API's it will require some tweaking but you can easily get them as well. Anyway you can always add some "middleware" in the form of a python script or whatever that your Splunk can use to get the data.