AT-78-01-4 -- A Short Method to Determine Seasonal Efficiency of Fossil-Fired Heating Systems for Labeling Purposes

The method described here is based on a Standard Table of Seasona1 Efficiencies and the followingexperimental data, which represent the furnace or boiler under test:The conventional, ANSI efficiency measured in the lab tinder steady state conditionsTwo (dynamic) flue temperatures measured at 5 min. after flame-on and at 5 min. after flame-off, andA quantitative description of energy saving features.

The inputs are sufficient to locate or interpolate the appropriate Seasonal Cost Efficiency in the Table. Cost Efficiency (or Cost COP) is defined as the ratio between total output energy (in terms of its worth on a current $/BTU or $/kWh scale, respectively) and the total cost of the input energy. This definition of efficiency is necessary in order to avoid inconsistencies with total operating cost. It also makes possible operating cost comparisons among different types of heating systems; including hybrid heat pumps. Although it is a new concept, System Cos~ Efficiency is identical to conventionally defined system efficiencies for systems consuming only one type of fuel.

Citation: ASHRAE Transactions, Volume 84, Part 1, Atlanta, GA



Product Code(s): D-AT-78-01-4