Hello everyone,
Today I received an offer for the ground drilling and need some help interpreting the data.
I was given the following information in a document:
Your heat pump: Nibe Systemtechnik GmbH: NIBE F1255-6
Planned heating capacity 6 kW
Annual heating energy demand 6,450 kWh
Annual domestic hot water energy demand 4,000 kWh
Annual heating profile Standard new build load profile
YOUR GEOLOGICAL CONDITIONS
Undisturbed site-specific ground temperature 9.7 °C (49.5 °F)
Specific thermal conductivity of geological layers 2.2 W/(m*K)
Number of boreholes 2
Depth per borehole 60 m (197 ft)
Flow type Turbulent
Probe type Single U-tube 40
Energy output: Your borefield generates 8.2 MWh (megawatt-hours) per year
According to the engineering office’s calculation, my house has a heating load of 4,297 W (without domestic hot water).
There is a mistake with the planned heat pump; it should be the Nibe S1255-6-PC, not the F1255-6. However, I don’t think this makes a difference here.
Is it normal to size the probes based simply on the maximum heating capacity of the heat pump (6 kW)?
I don’t understand the two values given for annual heating energy demand and domestic hot water energy demand. Why is 6,450 kWh being used now?
An annual domestic hot water energy demand of 4,000 kWh for a three-person household also seems very high to me, doesn’t it?
Can someone clarify this?
In the end, I am surprised by the two boreholes and the associated estimated costs (almost 14,000 €).
I had actually hoped to manage with just one borehole due to the relatively low heating load. According to the map from the state of Berlin, the ground in my area should provide about 35 W/m.
Best regards
Today I received an offer for the ground drilling and need some help interpreting the data.
I was given the following information in a document:
Your heat pump: Nibe Systemtechnik GmbH: NIBE F1255-6
Planned heating capacity 6 kW
Annual heating energy demand 6,450 kWh
Annual domestic hot water energy demand 4,000 kWh
Annual heating profile Standard new build load profile
YOUR GEOLOGICAL CONDITIONS
Undisturbed site-specific ground temperature 9.7 °C (49.5 °F)
Specific thermal conductivity of geological layers 2.2 W/(m*K)
Number of boreholes 2
Depth per borehole 60 m (197 ft)
Flow type Turbulent
Probe type Single U-tube 40
Energy output: Your borefield generates 8.2 MWh (megawatt-hours) per year
According to the engineering office’s calculation, my house has a heating load of 4,297 W (without domestic hot water).
There is a mistake with the planned heat pump; it should be the Nibe S1255-6-PC, not the F1255-6. However, I don’t think this makes a difference here.
Is it normal to size the probes based simply on the maximum heating capacity of the heat pump (6 kW)?
I don’t understand the two values given for annual heating energy demand and domestic hot water energy demand. Why is 6,450 kWh being used now?
An annual domestic hot water energy demand of 4,000 kWh for a three-person household also seems very high to me, doesn’t it?
Can someone clarify this?
In the end, I am surprised by the two boreholes and the associated estimated costs (almost 14,000 €).
I had actually hoped to manage with just one borehole due to the relatively low heating load. According to the map from the state of Berlin, the ground in my area should provide about 35 W/m.
Best regards
4000 kWh for hot water is not much. Keep in mind, they are talking about heat energy, not electricity.
But yes, I would insist on drilling, a double U-loop probe. It shouldn't exceed 100 meters (330 feet) anyway (and even if it does, you simply go deeper than 100 meters instead of installing two probes).
But yes, I would insist on drilling, a double U-loop probe. It shouldn't exceed 100 meters (330 feet) anyway (and even if it does, you simply go deeper than 100 meters instead of installing two probes).
But online I find estimates of 600–800 kWh per person for hot water. For 3 people, that would be roughly in the range of 1800 to 2400 kWh.
Here, almost double that amount is indicated.
On other websites, it says that some do not include any additional allowance for hot water at all, because the standards for heating load calculation already include enough margin (e.g., solar gains) to cover it. Also, the heating system never does both at the same time; hot water preparation is given priority.
However, I first want to understand the numbers so I can then argue based on them. Does anyone have an idea where the heating energy demand of 6450 kWh per year comes from?
PS: Drilling over 100 m (330 feet) is apparently not possible, as that falls into the category of mining and requires completely different permits, which are difficult to obtain.
Here, almost double that amount is indicated.
On other websites, it says that some do not include any additional allowance for hot water at all, because the standards for heating load calculation already include enough margin (e.g., solar gains) to cover it. Also, the heating system never does both at the same time; hot water preparation is given priority.
However, I first want to understand the numbers so I can then argue based on them. Does anyone have an idea where the heating energy demand of 6450 kWh per year comes from?
PS: Drilling over 100 m (330 feet) is apparently not possible, as that falls into the category of mining and requires completely different permits, which are difficult to obtain.
Is my assumption correct that a single borehole of 120m (394 feet) would be more cost-effective than two boreholes of 60m (197 feet) each?
(I understand that this probably cannot be calculated simply based on the performance of the ground probe).
Are two boreholes advantageous in any way?
(I understand that this probably cannot be calculated simply based on the performance of the ground probe).
Are two boreholes advantageous in any way?
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