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Hi,
I want to model a system which activates heat pumps (Type 793) sequentially in case the temperature of different zones drops below a certain amount and the need for heat exceeds the amount that a single heat pump can provide. How can I do it?
Thanks
Shams
@shamsoddinghiami Do you want to control the sequential activation off of a zone temperature, or off of the total desired load?
If you want multiple on/off signals from a monitored temperature (signal device 1 ON when the temperature drops below 20 C, device 2 ON when the temperature drops below 19 C, etc.), you can use any of the multi-stage differential controllers in the TESS Controllers library. Types 1502/1503 allow up to 100 sequential stages with different setpoints for each stage. The user can define whether prior stages should stay on or turn off when a new stage comes on. Types 970/971 are similar to Types 1502/1503, but allow the user to specify individual deadbands for each stage, as well as minimum run-time or time delays before starting/stopping each new stage. If you're monitoring multiple zone temperatures, you may need an equation block to calculate the minimum/maximum temperature of all zones first, then send that value to the controller.
If you want to control a central plant of devices based on the total desired load, you can use the staged device controller (Type 910) in the TESS Controllers library. The staged device controller is given a total desired value (total load to supply) as an input at each time step. It will run device 1 until its part-load ratio exceeds a user-specified threshold, then add a second device and share the load equally between the two until both device's maximum part-load ratio is exceeded and a third is brought online, and so forth.
