Draughts - Windows
| Outside Temperature |
1deg C |
| Outside Conditions |
Rain/sleet/windy |
| Outside Relative humidity |
100% |
| Air Velocity |
1m/s |
| Inside Temperature |
18deg C |
| Total window perimeter |
31m |
| Average gap size |
0.001m |
| Aperture area for draught, 50% |
0.015m2 |
| Air volume flow rate |
0.015x1 = 0.015m3/s |
| Specific enthalpy of outside air |
12kJ/kg |
| Specific enthalpy of heated, inside air |
29kJ/kg |
| Specific volume of outside air |
0.772m3/kg |
| Air mass flow rate |
(0.015x1)/0.772 = 0.02kg/s |
| Heating requirement |
(29-12)x0.02 = 0.34kW |
| Energy Consumption at 80% Boiler Efficiency |
0.34kW/0.8 = 0.425kW |
Draughts - Door
| Outside Temperature |
1deg C |
| Outside Conditions |
Rain/sleet/windy |
| Outside Relative humidity |
100% |
| Air Velocity |
1m/s |
| Inside Temperature |
18deg C |
| Total window perimeter |
5.6m |
| Average gap size |
0.001m |
| Aperture area for draught |
0.0056m2 |
| Air volume flow rate |
0.0056x1 = 0.0056m3/s |
| Specific enthalpy of outside air |
12kJ/kg |
| Specific enthalpy of heated, inside air |
29kJ/kg |
| Specific volume of outside air |
0.772m3/kg |
| Air mass flow rate |
(0.0056x1)/0.772 = 0.00725kg/s |
| Heating requirement |
(29-12)x0.00725 = 0.123kW |
| Energy Consumption at 80% Boiler Efficiency |
0.123kW/0.8 = 0.154kW |
Draughts - Gas Boiler
| Outside Temperature | 1deg C | | Outside Conditions | Rain/sleet/windy | | Outside Relative humidity | 100% | | Boiler Input Power | 13.2kW | | Inside Temperature | 18deg C | | Air:Natural Gas Combustion Ratio (By Volume, 10% excess air) | 10.472:1 | | Natural Gas Energy Content | 40100kJ/m3 | | Gas flow rate | 13.2/40100 = 3.29x10-4 m3/s | | Air flow rate | 10.472x3.29x10-4 = 3.44x10-3 m3/s |
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| | Specific enthalpy of outside air | 12kJ/kg | | Specific enthalpy of heated, inside air | 29kJ/kg | | Specific volume of outside air | 0.772m3/kg | | Air mass flow rate | (3.44x10-3)/0.772 = 4.46x10-3kg/s | | Heating requirement | (29-12)x4.46x10-3 = 0.076kW | |
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