Obviously, for any given absorber situation( the area of absorber, the amount of sunlight energy hitting it, the degree to which it is insulated from the environment against natural buoyant convection and heat loss due to air motion from wind, the emissivity of it's surface etc.) the higher it's temperature the more energy you lose to the environment. So we need to look at the function of solar input, ambient temperature, windspeed, emissivity etc. and then take the function which describes the temperature of the heat engine's input that maps to it's efficiency of converting said heat to electricity, mulitply the two for a function describing net energy output at a given absorber temperature, and then solve to find the optimum temperature at which to operate the absorber. In other words during a less sunny day you might net more electricity if you actually operate the absorber/boiler at a lower temperature than 500 degrees. This does not seem to have been done in the white cliffs project although maybe it was done with control systems with searching algorithms or I missed that part.

It appears that collector efficiency was quite good even at low insolation levels, but would probably be lower for the solar fire due to lower concentration ratio, which was about 175 for this thing.

it is clear from table xvi on page 253 and onwards that maintenance is a major issue for this thing even after the initial issues were worked out, including several days downtime per year , new pistons and all kinds of stuff as things wear out on it, and the cost must be substantial. Components need to be replaced after several thousand hours! That's not long really. In the case of biomass the assumption is that it is running almost all the time, so that is a couple times a year.

cost 163,000 for actual electricity generation stuff and collectory use energy output and compare with soalr panels , need to adjust for inflation etc. too that was in 88 assuming 2.3% that is equivalent to $280,000 eyeballing from the figures, in columbia missouri they get about 7 sun hours a day in snew south wales (http://www.livingin-australia.com/sunshine-hours-australia/) so 210 per month average so multiply by 10% for cheap solar panels, 21 kWh for a 1 kw array assume $2 per watt, to produce the 1880 kWh per month in april you would need $179,000 of solar panels. However this is a prototype system. But again maintenance is going to kill you most likely. Also they may have been raising the grade of heat using the oil fired boiler so that 1880 figure might be too high etc. However there is clearly promise here for maintenance free stirlings.


if people in this community are to earn $250 an hour the maintenance issues are even worse.

this is in australia where there is craploads of sun 7 sun hours per day vs 4.73 in missouri, biomass is that much more favorable in missouri therefore.

all the auxiliary stuff consumes a ton of energy as shown in table xIII page 219 from 10 to 20 percent of total , transmission losses are large, none of which are a problem for stirlings,

figure 79 seems to have a mistake, it is assumed that the pumping losses are taken directly out of the steam energy but they are not, they are taken from either electric or shaft power

BTW free piston engines produce power at a very consistent freuency which can readily be designed to be 60 hz as they have a resonant mass- spring system and their frequency ouptut does not change as their output power changes.