Reducing Transformer Losses

As opposed to what?

If their point of use is 120V single phase loads and 208V single and 3 phase loads, how else would you propose doing it?

By specifying one larger, more efficient transformer and wiring the 120/208 from that unit.

I have not seen or measured the units in place yet (just see them on a drawing and not enough info to calculate efficiency), but I understand the smaller units can be inefficient (both in terms of electrical power loss, and heat output). Just trying to wrap my head around the issue of so many transformers before my site visit.

A retail space that large is going to have large HVAC loads. I bet there are many 600V three phase motors in use on those units. Also... it is a good bet, that most of the lighting systems are 347V, which is the phase to neutral voltage on a 600V system.

Yes there are numerous motors and lighting circuits using higher voltage. Most of that will have to stay, we're taking a look at other electrical draws to see what might be able to be reduced.

If you can afford the energy for a system that uses a 600 volt 1000 amp three phase feeder you can also afford the few extra KWh's a day that the 12 transformers are consuming.

To me this sounds like one of those typical middle manager projects that just comes down to someone trying to justify their job by spending a lot of company money to save a little because it looks good on paper.

Yes they can afford the extra energy. They are quite profitable now. But they are also a national chain with over 500 stores and more opening every few months or more frequently. We don't know what the transformers are drawing, so we asked.

We are consultants and don't have to justify our job. We've been helping this chain with HVAC for the better part of 30 years, and they want us to look into electrical energy issues now.

The chain is aiming for large energy reductions by 2015, and aiming for net zero operational energy on their stores by 2020. They will be rewarded in the market for making the effort, because it does 'look good on paper'.

Construction and engineering is greatly held back by the attitude of 'we've always done it this way' and 'it's not worth trying'. Granted sometimes that attitude makes sense, but most of the time, questioning the assumptions leads to better designs for the clients.

Let me see if I have this right:

Your company is a consulting firm, and you are consulting a forum for advice?

If electrical engineering is not your field of expertise, then you need to consult a firm that is, or hire an Electrical Engineer .There are too many variables and unknowns in your question, and I doubt there is enough room on this forum to give a detailed analysis of the situation.

My first impulse reaction would be to investigate load-shedding and peak load management strategies, and lighting efficiencies,as these generally give a quick ROI.