Hello,
Our building specification states that we will get a ground-source water heat pump. I was even able to convince the developer to specify the brand Vaillant without much trouble.
But how should the Vaillant heat pump be sized? How many boreholes will I need?
Our house will be about 180 m² (1,937 sq ft) over two floors, mostly tiled.
Does anyone have a calculation method for this?
Our building specification states that we will get a ground-source water heat pump. I was even able to convince the developer to specify the brand Vaillant without much trouble.
But how should the Vaillant heat pump be sized? How many boreholes will I need?
Our house will be about 180 m² (1,937 sq ft) over two floors, mostly tiled.
Does anyone have a calculation method for this?
J
Jürgen VausB8 Jul 2009 15:47here is the most important information you should know.
Design of the heat pump
When properly sized for monovalent operation, the heat pump system serves as the sole heat source and covers the entire heating demand of the building (according to EN 12831; previously DIN 4701). Depending on the energy supplier (utility), allowances for restriction periods in the design must be considered. Utilities may interrupt supply for up to 3 times 2 hours within 24 hours. Due to the thermal inertia of the building, 2 hours of restriction time are not included in the calculation of the required energy amount.
Between two interruption periods, utilities must provide twice the duration of the previous restriction period as an allowed supply time.
For an "initial" sizing, a rough calculation of the heating load is possible. The heated floor area forms the basis. The heated area (in square meters) is multiplied by the following specific heating loads:
- Passive house 10 W/square meter
- Low-energy house 40 W/square meter
- New build with good thermal insulation 50 W/square meter
- House with standard thermal insulation 80 W/square meter
- Older house without special insulation 120 W/square meter
Example:
A new build with good thermal insulation and an area of 180 square meters. With a maximum restriction time of 3 x 2 hours and at minimum outdoor temperature (EN 12831), the power demand is approximately 10 kW. This results in a daily heating energy requirement of 240 kWh (10 kW × 24 h).
Due to the restriction periods (3 x 2 hours), only 18 hours per day are available to cover the maximum daily heating demand. Because of the building’s thermal inertia, two hours remain unconsidered in this calculation.
240 kWh / 20 h = 12 kW
According to this calculation, a heat pump with a capacity of 12 kW is sufficient.
Domestic hot water heating
In typical residential construction, the maximum hot water demand is calculated at approximately 50 liters per person per day at about 45°C (113°F). This requires an additional heating power of approximately 0.25 kW per person with a heating time of eight hours. Allowances and heat pump sizing can be calculated precisely according to DIN 4708 Part 2.
This "initial" calculation is not very detailed and is only intended for pre-planning purposes. The final sizing of the required heating capacity can only be done after a detailed heating load calculation.
When selecting the heat pump, the characteristics of the possible heat sources must be taken into account.
Regards, Jürgen
Design of the heat pump
When properly sized for monovalent operation, the heat pump system serves as the sole heat source and covers the entire heating demand of the building (according to EN 12831; previously DIN 4701). Depending on the energy supplier (utility), allowances for restriction periods in the design must be considered. Utilities may interrupt supply for up to 3 times 2 hours within 24 hours. Due to the thermal inertia of the building, 2 hours of restriction time are not included in the calculation of the required energy amount.
Between two interruption periods, utilities must provide twice the duration of the previous restriction period as an allowed supply time.
For an "initial" sizing, a rough calculation of the heating load is possible. The heated floor area forms the basis. The heated area (in square meters) is multiplied by the following specific heating loads:
- Passive house 10 W/square meter
- Low-energy house 40 W/square meter
- New build with good thermal insulation 50 W/square meter
- House with standard thermal insulation 80 W/square meter
- Older house without special insulation 120 W/square meter
Example:
A new build with good thermal insulation and an area of 180 square meters. With a maximum restriction time of 3 x 2 hours and at minimum outdoor temperature (EN 12831), the power demand is approximately 10 kW. This results in a daily heating energy requirement of 240 kWh (10 kW × 24 h).
Due to the restriction periods (3 x 2 hours), only 18 hours per day are available to cover the maximum daily heating demand. Because of the building’s thermal inertia, two hours remain unconsidered in this calculation.
240 kWh / 20 h = 12 kW
According to this calculation, a heat pump with a capacity of 12 kW is sufficient.
Domestic hot water heating
In typical residential construction, the maximum hot water demand is calculated at approximately 50 liters per person per day at about 45°C (113°F). This requires an additional heating power of approximately 0.25 kW per person with a heating time of eight hours. Allowances and heat pump sizing can be calculated precisely according to DIN 4708 Part 2.
This "initial" calculation is not very detailed and is only intended for pre-planning purposes. The final sizing of the required heating capacity can only be done after a detailed heating load calculation.
When selecting the heat pump, the characteristics of the possible heat sources must be taken into account.
Regards, Jürgen
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