Hello, maybe someone has an Excel spreadsheet or formulas to help me calculate the theoretical energy consumption of my heat pump for a specific day?
The average consumption of 23 kWh/day seems a bit high to me for a new KFW55 house. I know there is still residual moisture in the building, but does that really make such a big difference?
What would really help me are formulas to estimate the consumption, or maybe my heat load calculation is a bit low.
Data:
KFW55 house with 132 m2 (1420 sq ft) of living space. December Lunos heat recovery ventilation, aerated concrete 42.5 cm (17 inches)
Footprint 9 m x 10 m (30 ft x 33 ft), 1.5 stories, ceiling height 2.59 m (8.5 ft)
3 people, including 1 toddler
Water-saving shower heads + Amphiro smart meter, max temperature 38°C (100°F)
Heat pump consumption over 18 days: 413 kWh
Average day/night temperature: 5°C / -1°C (41°F / 30°F)
Energy provider shutdowns twice for 1.5 hours each
Heat Pump
Rotex HPSU 308, 6 kW, 300 L (79 gallons) storage tank
Domestic hot water temperature set to 48°C (118°F)
COP A-7/W35 2.53 Heating capacity 4.2 kW
COP A2/W35 3.47 Heating capacity 5.5 kW
COP A10/W35 4.94 Heating capacity 8.6 kW
Standby heat loss at 60°C (140°F) kWh/24h: 1.3
Surface area of domestic hot water heat exchanger: 5.8 m2 (62 sq ft)
Average specific heat transfer: 2790 W/K
Domestic hot water volume: 27.8 L (7.3 gallons)
Storage charge/discharge heat exchanger
Volume: 12.4 L (3.3 gallons)
Surface area of charge heat exchanger: 2.5 m2 (27 sq ft)
Average specific heat transfer: 1200 W/K
Average room temperature: 21°C (70°F)
Heat load calculation
HT 83.11 W/K, HV 28.94 W/K, H Building 112.05 W/K
Building transmission losses (T Geb) 2681 W, Ventilation losses min (Vmin) 186 W, Ventilation losses actual (V Geb) 638 W
Building losses (N Geb) 3320 W, Heat load building (HL Geb) 3320 W
Building area (An Geb) 145.8 m2 (1570 sq ft), Building volume (Vn Geb) 384.0 m3 (13560 cu ft), Surface area (A) 388.9 m2 (4186 sq ft)
Heat load per area (HL Geb / An Geb) 22.8 W/m2
Heat load per volume (HL Geb / Vn Geb) 8.6 W/m3
HT 0.21 W/(m2·K)
I would like to calculate the following:
How many hours does the heat pump run, for example, during one day?
Energy consumption in kWh per day?
What effect does a temperature difference of ±1°C have?
Thank you very much
The average consumption of 23 kWh/day seems a bit high to me for a new KFW55 house. I know there is still residual moisture in the building, but does that really make such a big difference?
What would really help me are formulas to estimate the consumption, or maybe my heat load calculation is a bit low.
Data:
KFW55 house with 132 m2 (1420 sq ft) of living space. December Lunos heat recovery ventilation, aerated concrete 42.5 cm (17 inches)
Footprint 9 m x 10 m (30 ft x 33 ft), 1.5 stories, ceiling height 2.59 m (8.5 ft)
3 people, including 1 toddler
Water-saving shower heads + Amphiro smart meter, max temperature 38°C (100°F)
Heat pump consumption over 18 days: 413 kWh
Average day/night temperature: 5°C / -1°C (41°F / 30°F)
Energy provider shutdowns twice for 1.5 hours each
Heat Pump
Rotex HPSU 308, 6 kW, 300 L (79 gallons) storage tank
Domestic hot water temperature set to 48°C (118°F)
COP A-7/W35 2.53 Heating capacity 4.2 kW
COP A2/W35 3.47 Heating capacity 5.5 kW
COP A10/W35 4.94 Heating capacity 8.6 kW
Standby heat loss at 60°C (140°F) kWh/24h: 1.3
Surface area of domestic hot water heat exchanger: 5.8 m2 (62 sq ft)
Average specific heat transfer: 2790 W/K
Domestic hot water volume: 27.8 L (7.3 gallons)
Storage charge/discharge heat exchanger
Volume: 12.4 L (3.3 gallons)
Surface area of charge heat exchanger: 2.5 m2 (27 sq ft)
Average specific heat transfer: 1200 W/K
Average room temperature: 21°C (70°F)
Heat load calculation
HT 83.11 W/K, HV 28.94 W/K, H Building 112.05 W/K
Building transmission losses (T Geb) 2681 W, Ventilation losses min (Vmin) 186 W, Ventilation losses actual (V Geb) 638 W
Building losses (N Geb) 3320 W, Heat load building (HL Geb) 3320 W
Building area (An Geb) 145.8 m2 (1570 sq ft), Building volume (Vn Geb) 384.0 m3 (13560 cu ft), Surface area (A) 388.9 m2 (4186 sq ft)
Heat load per area (HL Geb / An Geb) 22.8 W/m2
Heat load per volume (HL Geb / Vn Geb) 8.6 W/m3
HT 0.21 W/(m2·K)
I would like to calculate the following:
How many hours does the heat pump run, for example, during one day?
Energy consumption in kWh per day?
What effect does a temperature difference of ±1°C have?
Thank you very much
B
Bitknight20 Feb 2018 09:31@Saruss
First of all, thank you.
According to the heating load calculation, the heat loss is 638W.
That’s 24 hours * 638W = 15.3 kWh heating demand per day.
Divided by 3 = 5.1 kWh electricity.
Standby heat loss is 1.3 kWh per day.
Domestic hot water consumption is 0.2 kWh per person = 0.6 kWh.
So that’s 7 kWh if I understand correctly, right?
First of all, thank you.
According to the heating load calculation, the heat loss is 638W.
That’s 24 hours * 638W = 15.3 kWh heating demand per day.
Divided by 3 = 5.1 kWh electricity.
Standby heat loss is 1.3 kWh per day.
Domestic hot water consumption is 0.2 kWh per person = 0.6 kWh.
So that’s 7 kWh if I understand correctly, right?