By nature, terminal units (fan coil, radiator, AHU,) close to the pump are working in overflow creating underflows in others terminal units.
For instance, in heating system, it frequently happens that rooms close to the boiler room and then close to the pump are in overflow and consequently overheated, whereas rooms further away reach the temperature with difficulty. Room temperature deviation reaches easily 2°C to 4°C.
This situation also leads to a higher total flow than required and therefore increases electrical pump consumption and poor power transfer at interfaces.
This conducts most of the time to put more productions units (boilers, chillers) into operation than would normally be necessary and affects the efficiency of condensing boilers or the chillers COP.
These different effects can globally create together an over-consumption from 10% up to 35%!
Heating calculation example
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Average room temperature deviation: 2°C |
Energy impact : 12% to 22% (see fact N°12)
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Pump over-consumption: 40% (Fact N° 7) |
Energy impact : 0,2% to 0,6 %
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Lower condensing boiler efficiency |
Energy impact : 1% to 3% (see fact N°4)
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Total: 13,1% to 24,8%
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Cooling calculation example
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Average room temperature deviation: 1°C |
Energy impact : 12% to 18% (see fact N°13)
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Pump over-consumption: 40% (Fact N° 7) |
Energy impact : 2,8% to 6,8% (see fact N° 6)
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Lower Average Chiller efficiency (COP) |
Energy impact : 5% to 15% (see fact N° 1)
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Total : 18,7 % to 35,0%
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Reference case:
Granloholm, residential area in Sundsvall, Sweden. 15% energy savings
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