AUTOFLAME Mk7 User Manual

6.2 Heat Flow Metering
Heat Flow Metering is simply measuring the amount of heat being transferred to the water by a hot
water boiler. If we know the stack losses and the standing losses of the boiler at any moment then
whatever energy is left over must be going into the water.
From the E.G.A. stack losses = 100 – combustion efficiency
Radiation losses are specific to the boiler, 1% radiation losses are typical for a packaged boiler
operating at maximum continuous rating. The loss is constant regardless of boiler output so at 50%
firing rate it would be 2% of the energy input.
The total heat in at any time is given by the heat flow metering so we can calculate the instantaneous
heat going into water. By integrating these values we can get a totalised value.
6.2.1 Calculation for Heat Output and Volume Flow
Efficiency%100%

Stackloss
RadiationLosses100
FiringRate

UsefulHeatintoWaterTotalHeat
Efficiency
100
VolumeFlowinlbs/hr
UsefulheatMBTU/Hr
SPHtBTU/lb/°F󰇛FlowTemp–ReturnTemp󰇜


VolumeFlowincuftHr
VolumeFlowinlbs hr
⁄
DensityofWateratReturnTemperature
Since1cuftHr0.124676USG.P.M.
VolumeFlowinUSG.P.M.VolumeFlowincuftHr0.124676
6 Steam and Heat Flow Metering
October 2014
Mk7 Manual: Expansion Board Set-Up Guide
Page 109

AUTOFLAME Mk7 Specifications

General

Brand	AUTOFLAME
Model	Mk7
Category	Measuring Instruments
Language	English