How much electricity does a heat pump use to heat a 100 m2 living space?
How much electricity is consumed by a heat pump for heating a living space is one of the basic parameters that can determine the cost-effectiveness of using heat pumps.
Input data
As an example, here we will present the use of a geothermal heat pump with a horizontal geothermal collector for heating a living space of 100 m2.(Geothermal Heating and Cooling)
We will assume that the ceiling height is 2.6
m.
The residential building is located in an area
with a continental climate with an average annual temperature of 10 0
C.
We will assume that the soil around the
facility to accommodate geothermal horizontal collectors has a specific thermal
effect of 30 W / m2.
The required amount of heat for heating
according to heat losses is 5.94 kW.
The working substance in the heat pump is a zeotropic mixture
that has the following characteristics:
• Evaporation temperature: 0 ° C
• Condensation temperature: 40 ° C
Area size that requires 1 kW of thermal energy:
A = 100 m2 Po
= 5.94 kW
π = π΄ / ππ = 100 /
5.94 = 16.83 π2 / ππ
Calculation of condenser power to obtain the required amount
of thermal energy:
ππππ = π΄ / π = 100 /
16.83 = 5.94 ππ≈ 6 kW
Compressor selection
From the tables of scroll compressor manufacturers, the data
of an individual compressor can be read depending on the working substance
used.
Data read for Danfoss scroll compressor at evaporation
temperature 0 ° C and condensing temperature 40 ° C:
Heating capacity [W] 6522
Input power [W] 1376
Nominal current [A] 2.69
Mass flow rate [kg / h] 107
Compressor heating COP (coefficient of performance) 4.74
This compressor provides 4.74 kW of thermal energy for 1 kW
of electricity.
Geothermal collector sizing
A nomogram is used for sizing, which in a
simple way shows all the necessary parameters according to the soil quality of
30 W / m2.
From the nomogram we can read that for the required thermal
energy of 6 kW it is necessary:
• 5 kW evaporator
• Ground area 190 m2
• Geothermal collector pipe length 390 m
Calculation of electricity consumption
From the following expression we can calculate the power of
the compressor:
πππππ = ππππ / πΆππ = 5.94 /
4.74 = 1.25 ππ
If we include the obtained results in the expression for
total strength, we get:
Qisp + Pkomp = Qkon = 5 + 1.25 = 6.25 kW
It is necessary to calculate the volume of the residential
building according to the formula:
V = A * h = 100 * 2.6 = 260 m3
The heating factor is π = ππ / π = 5.94 / 260 = 0.022846 ππ / π3
The power of the compressor is 1376 W, or 1.376 kW.
The budget takes into account the winter time calculation
according to the tariffs valid in Bosnia and Herzegovina:
• VT from 07-13 and 16-22 hours 12 h * 200 days = 2400 h per
VT
• MT from 13-16 and 22-07 hours 12 h * 200 days = 2400 h per
MT
Electricity consumption during compressor operation of 1 h: W
= P * t = 1.376 * 1 = 1.376 kWh
W = electricity (amount of work) kWh
P = power (kW or kVA)
t = time in hours (h)
Electricity consumption during one day (12 h per VT, 12 h per
MT) VT: 1.376 * 12 = 16.512 kWh MT: 1.376 * 12 = 16.512 kWh
We will assume that the number of days in the heating season
is 200.
Electricity consumption during the heating season:
VT: 16.512 * 200 = 3302.4 kWh
NT: 16.512 * 200 = 3302.4 kWh
TOTAL CONSUMPTION: 6604.8 kWh
Electricity consumption in euros according to the valid price
list:
VT: 3302.4 * 0.0424 = 140.02 euros
MT: 3302.4 * 0.0212 = 70.01 euros
TOTAL CONSUMPTION DURING THE HEATING SEASON: 210.03 euros
Given that the number of days in the heating season is 200 and the
average number of days in the month is 30, the residential building was heated
for about 6.66 months. As the consumption during the 200 days of the heating
season was 210.03 euros, we will get that the monthly electricity bill,
according to the current price of electricity for households in Bosnia and
Herzegovina would be 31.53 euros per month, assuming continuous heating of 100
m2.
That was interesting, good job
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