Thanks for the feedback. Either way I need to give a report on why it will work or not work. Does anyone know of this being documented before or examples of it. Below is from a consultant I am working with. This is what he knows of these type of systems:
It is a well understood fact that there are significant losses in conversion of PV power to AC when all is said and done between the inverter the transformer, the diodes, etc there is a good 10% loss of efficiency. A high quality intelligent DC to DC converter probably has less than 2% losses. At night a high quality intelligent power supply, basically a rectifyer with a transformer and some electronics, is also quite efficient ,so it would take over when the solar goes down. We would need these to be located centrally in the building (or have multiples of them) so that the losses in the 12V wiring are small.
As for outlets we can use the new aircraft standard which is available for most if not all laptops, cellphones etc. We can then order our task lights with the same plugs which would make them difficult to steal. The task lights will be slightly cheaper as they do not require their own power supply.
Speaking of power supplies most of those used presently are quite dumb, they do not modulate their output dependent on demand, so their only fluctuation in energy use is due to the inductive effect in their transformers, a small amount. That alone could pay for the system in less than two years.
So here is what I think we could do. We could estimate the actual savings in a rough order of magnitude. From your end the additional work is the design of the system, the specification of the DC to DC converter, the AC to DC power supply and the specification of the 12V wiring and outlets. The client should decide whether to have the 12V outlets on the furniture system (which would require a bit of coordination) or directly on the raised floor in a monument or recessed pocket.
I do not think this is that difficult, we did a similar design for a building that unfortunately never got built, but at that time we did not have the airline standard. That has simplified things quite a bit.
Ideally, we can monitor this and keep a log of what the uses are and we could then estimate the savings. In addition, for those who worry about EMF apparently they believe DC is much better than AC (I do not subscribe at all to those worries, my feeling is that if EMF was such a danger the difference between the death rate of office workers today and 50 years ago would be statistically spectacular).
Any comments? Thanks.
