But it cannot waste the heat that is not produced.- as you believe; or not? If the efficiency was indeed so low, who has paid the huge electricity bill? It could be as high as 85 million kWh- how much does this cost in Florida? peter
On Sun, May 15, 2016 at 3:39 PM, Jed Rothwell <jedrothw...@gmail.com> wrote: > I mentioned that an HVAC engineer estimated that the Rossi device heat > transfer efficiency is probably low. This is called the AFUE (annual fuel > utilization efficiency). Typical AFUE are: > > 56 to 70% for old furnaces > 80 to 83% for mid-range efficiency > 90 to 99% for advanced, high efficiency heaters > > http://energy.gov/energysaver/furnaces-and-boilers > > The thing is, the HVAC engineer said that as a heater, Rossi's gadget is > poorly designed. It should be at the low end of the scale. I am out of my > depth here, but as I recall, the reasons were: > > A heater should have low surface area. Most are large cylinders to reduce > surface area. This heater is series of small square boxes, which has the > most surface area per unit of volume. > > This boiler has external pipes running from one box to the next, outside > the boxes. Every pipe radiates heat, even if they are insulated. > > The path from the fluid inlet to the outlet should be as long as possible, > and convoluted. With each box in this heater, the water goes in and comes > right out, in a short path. In a boiler the "fluid" is either the water you > want to heat, or in a fire tube boiler, it is the hot combustion product > gas. See: > > > http://www.spiraxsarco.com/Resources/Pages/Steam-Engineering-Tutorials/the-boiler-house/shell-boilers.aspx > > This is why I estimate the heat transfer efficiency is ~70%. The other 30% > would be waste heat released inside the shipping container. This is only a > very rough estimate by me. I suppose it could be higher given the > insulation. But I doubt that it higher than the low end of today's the high > efficiency heater. That would be 90%. So, a 1 MW heater will have between > 100 and 300 kW of waste heat. > > - Jed > > -- Dr. Peter Gluck Cluj, Romania http://egooutpeters.blogspot.com
