Dear Ron and Andrew and Lanny RON >This is the first time I can recall seeing the number 2.3 MJ/kilo. This must be associated with some initial moisture?
It has to be the heat loss for a 'typical' exhaust temperature. The HHV-1.32 MJ/kg is often given as the LHV value though it is not really calculated correctly. The correct 'common' or 'average' value would be HHV-1.38 but there is not use protesting it because the other method is so entrenched. 2.3 would include some heat in gases above 100C. The HVAC and boiler industry in the US uses 150 C as the minimum useable exhaust temperature so the 1.32 does not apply in that case. An 'efficiency' is a ratio. There are many efficiencies in a stove. The system efficiency is perhaps the best description for the work done/energy theoretically available. Another efficiency is take (the work done/(energy theoretically available x combustion efficiency)) where combustion efficiency really means the % of heat that was not lost to unburned gases. Yet another is the potential heat x the combustion efficiency considering also the mechanical losses to arrive at the actual heat available from the fire. This can be used to determine the actual firepower for space heating and cooking considerations. If the heat gained by the pot including the pot material and what is inside it is divided by that number, you get the heat transfer efficiency. That can be useful for tuning the stove's performance. If you want a measure of fuel efficiency, and to be able to predict the fuel consumption in future, you want the system efficiency which is also the easiest to calculate. That tells you how efficiently the fuel resource is being applied to the 'work' of cooking. Regards Crispin _______________________________________________ Stoves mailing list to Send a Message to the list, use the email address [email protected] to UNSUBSCRIBE or Change your List Settings use the web page http://lists.bioenergylists.org/mailman/listinfo/stoves_lists.bioenergylists.org for more Biomass Cooking Stoves, News and Information see our web site: http://stoves.bioenergylists.org/
