Backup control temperatures

[jmaguire1]

So there's a few different temperature thresholds we can care about in cases where you have a heat pump and backup. The naming can be a little confusing between all of them:

• BackupHeatingSwitchoverTemperature: This is for systems with separate backup. Think a HP where an existing furnace is kept in place for backup. Below this temperature, only the backup can run. Above this temperature, only the heat pump can run.
• CompressorLockoutTemperature: The minimum temperature a heat pump can run at. Below this, only the backup runs. Above this, both the backup and heat pump may run at the same time.
• MaximumBackupTemperature: I don't think this one is in HPXML yet, but a max temperature at which the backup can run. Above this temperature, the backup will never turn on. Below this, backup and HP may run at the same time. I asked Kendall to add this in backup control to dos #146.

This issue might be helpful: NREL/OpenStudio-HPXML#1273.

Right now we can parse in "BackupHeatingSwitchoverTemperature", but I think we're using it like it's "CompressorLockoutTemperature"? See where we parse this here: https://github.com/kendallbaertlein/OCHRE/blob/1a4998d0e0d24ca4fd4ee32b35d3b01b1138f316/ochre/utils/hpxml.py#L860