The flow rate is necessary because, as I pointed out, a long test is required (several days contemplated). There is no pump, because the cooling water will be supplied from a domestic tap. There will be a sight glass in the supply line to watch for entrapped air. The output of the heat exchanger will be collected in buckets on a digital scale, and the flow meter data will be periodically checked against level marks on the bucket with a stop watch.
By using a heat exchanger, any questions about the steam quality in the primary circuit are made moot. The single-phase power will be measured simultaneously with two instruments, a PCE830 and a Tektronix PA1000. All the data, including the scale readings will be streamed in real time, with live video if bandwidth permits.
Much of what you see as complexity has been adopted in direct response to criticisms here and elsewhere of other validation tests. All these details are included in our published test plan, which I encourage you to read and think about in the context of possible objections that could arise if they were not included. We intend to establish an incontrovertible minimum COP for the system, to the best of our abilities and resources.
You can run a test using differential measurement for any length of time. Just empty the barrels after each measurement and start again. This will also show that the AURA can be cycled many times without loss of capability or damage.