[TRNSYS-users] Controlling Multiple Heat pumps and Stages

[Fred Betz]

I am trying to stage four 50-ton heat pumps on incrementally, but I don't know if I can do that with the Type 1221.

There is a control signal for the 1st stage and the 2nd stage of the heat pump. (Incidentally, from a past post about not getting more output from the 2nd stage of the heat pump. You have to set the 1st stage to 25 tons and the 2nd stage to 50 tons. Not 25 and 25.)

I know there is an input for # of heat pumps turned on. However, I would like to be able to turn the stages on individually. Therefore, HP1 starts at stage 1, turns on stage2, and then HP turns on stage 1. My understanding is that if HP1 has stage 1 and 2 turned on , HP2 will have both stages turned on as well.

In the past I piped the heat pumps (type668) up individually and controlled the valves to divert the flow appropriately. Do I still have to do this for Type 1221?

Does the scale factor account for this? For example, if I turn on both stages of HP1 and want 1 stage of HP2, do I set the scale factor to 1.5?

Is there a fancy controller already written for this, or do I have to create the logic myself?

Please advise,

Fred

Fred Betz  PhD., LEED AP
Sustainable Systems Analyst



AEI | AFFILIATED ENGINEERS, INC.
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P: 608.236.1175 | F: 608.238.2614
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