hey just thinking about something and not sure what is meant by it, i would like to know what the difference between the net and gross input of a boiler is i need to put it down in a project but cant really think of a good way to put it any help would be appreiceiate thankyou
quick question for some clever people ;)
- Thread starter hishamalbizri
- Start date
Does this help? Heat of combustion
gross is how much gas kw goes into the appliance
net is how heat comes out of boiler
net is how heat comes out of boiler
But the OP asked:
what the difference [is] between the net and gross input.
I don't think that is a typo; he is asking about net and gross calorific values, not about boiler efficiency.
gas is sold as gross calorific value
this figure varies at different times and in different locations due to the gas field supplying the fuel.
the gross cv is the amount of heat energy produced by the complete consumption of a known quantity of fuel.
when gas is consumed water is formed as a by-product
when this water condenses from vapour to liquid state latent heat is given up
this latent heat is not usually available for use as it passes out through the flue system so it cannot be regarded as part of total heat energy available
therefore it is not counted when quoting energy efficiencies
appliance are therefore invariably specified as a net cv
the cv is different for different fuels more heat can be obtained from burning 1 m3 of propane than from burning 1 m3 of methane
older appliances were rated as gross newer appliances are rated as net
Hope this helps Steve
this figure varies at different times and in different locations due to the gas field supplying the fuel.
the gross cv is the amount of heat energy produced by the complete consumption of a known quantity of fuel.
when gas is consumed water is formed as a by-product
when this water condenses from vapour to liquid state latent heat is given up
this latent heat is not usually available for use as it passes out through the flue system so it cannot be regarded as part of total heat energy available
therefore it is not counted when quoting energy efficiencies
appliance are therefore invariably specified as a net cv
the cv is different for different fuels more heat can be obtained from burning 1 m3 of propane than from burning 1 m3 of methane
older appliances were rated as gross newer appliances are rated as net
Hope this helps Steve
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