OK, interesting, I think this is the first time I see 24V DC non-latching valves. The user manual seems to refer to both 24V DC and 24V AC coil voltage, I assume this means two different types of solenoid?
Anyways, if you’ve already invested in the DC valves, you can modify the OpenSprinkler circuit by replacing the triacs with transistors like MPSA14. You won’t need the flyback diode any more because all current versions of OpenSprinkler have per-channel transient voltage suppressor (TVS) or MOV (these serve as surge voltage protectors). You can also use a relay board in conjunction with OpenSprinkler, but it will be much more bulky.