Heatmor 200X - Furnace Efficiency Measurements and Factors; Efficiency Metrics and Calculation Methods; Impact of Fuel Loading on Efficiency

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Efciency Measurements
There are several different ways that efciency is calculated. Each calculation has its ad-
vantages and disadvantages and no one way is necessarily better than the other, however,
when comparing one stove to another it is imperative that the same method be used. No
efciency number is able to give an exact expectation of an individual instillation. Many
factors combine to change the actual efciency number. The ambient air that the stove
is in will cause the efciency to reduce as the temperature that the stove is in gets lower.
Also having the stove sized too large for the needed heat load will cause the efciency to
decrease. The efciency of the stove will decrease as number of idle cycles increase. As
stated before, Moisture content of the fuel will also have a direct impact of the efciency.
HEATMOR™ has two different ways that our stoves are rated, Delivered Efciency and
Overall Efciency (SLM).
Delivered Efciency
The percentage of heat available in a test fuel charge that is delivered to a simulated heat-
ing. This is done by recording the ow of water and change of temperature through a heat
exchanger. The BTU’s recovered by the heat exchanger can be found and compared to the
BTU’s put into the stove.
Overall Efciency (SLM)
The efciency for each test run as determined using the CSA B415.1-10 stack loss method.
This method monitors the stack of the stove. The ue gas temperature and makeup (CO%,
CO2%, 02%, etc…) is recorded along with the weight of the fuel. These numbers are put
into an equation and an efciency is calculated based on how well the fuel was burned, and
how close to the ambient temperature the ue gas was.
Heating Value (HHV or LHV)
There is a lot that goes into calculating the efciencies of a stove. One major component
to nding out efciency is the amount of BTU’s put into the stove. Two values are used to
determine the amount of BTU’s/lb., Higher Heating Value (HHV), and Lower Heating Value
(LHV). This number is used to calculate the amount of BTU’s that were input into the stove.
Higher Heating Value
The higher heating value is the amount of BTU’s available in the fuel without respect to the
moisture content.
Lower Heating Value
The lower heating subtracts the energy needed to convert a standard moisture in the fuel
to gas.
Loading of the Furnace
Loading the furnace relative to the heat load will result if more efcient performance. More
nearly matching your fuel load to the current temperature conditions for an 8 to 12 hour
burn will result in longer burn cycles, higher overall burn temperatures and more efcient
performance. Your furnace has been rated for an 8 hour burn cycle.