If you assume a normal flow rate of 382m³/hr that's 106 l/S, which seems a bit high to me. Split between two units that's about 53 l/S each. If you look at the Appendix Q figures for the Brink Renovent Excellent, then the closest figure is 51 l/S where the SFP per unit is 0.79 W/l/S and the heat exchanger efficiency is 86%. Bear in mind this is without ducting, so the true figures will be worse, but that applies to any MVHR.
In terms of running cost, with an SFP of 0.79 per unit, then at the assumed normal flow rate of 106 l/S total you're looking at about 84 W continuous power consumption, or just over 2 kWh per day. In practice the power consumption will be a bit higher than this, because of the duct losses and also because the MVHR will be at a boost setting some of the time.
It's worth looking around at some others and comparing the performance figures, as there is a fairly wide variation. I'd be inclined to not over-size the MVHR units too much, as some have a higher SFP when they are run at low fan speeds (although doing this does tend to make them run more quietly).
I'd also double check the ventilation requirement against the actual house volume and air change rate per hour, or perhaps design for building regs minimum ventilation rates (given in table 5.1b in Part F), as I think you may be designing for a ventilation rate that is a bit higher than needed, which will push up your running costs.
Edited by jsharris, 18 August 2013 - 03:44 PM.