Table of contents:

Geothermal heat pump: costs and benefits
Geothermal heat pump: costs and benefits

Video: Geothermal heat pump: costs and benefits

Отличия серверных жестких дисков от десктопных
Video: #GoGeo - The Cost of Geothermal Heat Pumps 2023, January
Anonim

Geothermal heat pumps appear to be a resource-saving alternative to conventional heating systems. But is heating with geothermal energy really cheaper and more efficient? We have summarized the most important information about this new technology so that you can better assess costs and benefits.

Table of contents Table of contents Heating more efficiently with a geothermal heat pump: costs and benefits

  • A geothermal heat pump uses the heat inside the earth
  • How does a geothermal heat pump work?
  • Heat pump technology in comparison
  • Installation of the geothermal heat pump
  • Development costs vary depending on the method
  • How much are the acquisition costs for a geothermal heat pump?
  • The costs at a glance
  • Possible grants
  • Checklist: conversion to a geothermal heat pump

Table of contents Table of contents Heating more efficiently with a geothermal heat pump: costs and benefits

  • A geothermal heat pump uses the heat inside the earth
  • How does a geothermal heat pump work?
  • Heat pump technology in comparison
  • Installation of the geothermal heat pump
  • Development costs vary depending on the method
  • How much are the acquisition costs for a geothermal heat pump?
  • The costs at a glance
  • Possible grants
  • Checklist: conversion to a geothermal heat pump

A geothermal heat pump uses the heat inside the earth

In the so-called Kola drilling in the 1970s, the excavation was stopped at a depth of around 1, 200 meters because the earth there already had a heat of 180 degrees Celsius. Depending on the nature of the soil, a temperature of ten degrees Celsius can be measured from ten meters and from around twelve degrees Celsius from 100 meters. How hot it is inside the Earth can only be guessed at, but scientists assume up to 6, 000 degrees Celsius in the Earth's core. The idea of ​​using this energy for itself is obvious in the search for alternatives to gas and oil. Our neighbors in the north are pioneers in terms of technology and innovation: In Sweden, the market share of geothermal heat pumps for new buildings is around 90 percent. This is due in particular to political support for renewable energies and a market incentive program that has helped heat pumps make their breakthrough since the 1980s.

How does a geothermal heat pump work?

Emission-free heating with a geothermal heat pump works on a similar principle to that used in the refrigerator. A coolant is led into the earth in special plastic pipes and heated there using geothermal energy. This coolant is usually a brine-water mixture, which is why experts call the geothermal heat pump a brine-water heat pump. The coolant evaporates even at a low temperature of ten degrees Celsius. The rising gas is fed into the pump and compressed using compressors. The geothermal heat pump generates usable heat under this pressure. At around 50 degrees Celsius, the heat reaches the heating system via the condenser. The now condensed coolant is drained back into the earth via expansion valves that equalize the pressure level and the cycle starts again.

Did you know? With a geothermal heat pump, living spaces can also be effectively air-conditioned passively. This requires a heat exchanger, 3-way valves and a circulation pump. The elements ensure that the heat of the house is released into the earth - "natural cooling".

Heat pump technology in comparison

technology

Air source heat pump

Groundwater heat pump

Geothermal heat pump

Functional

wise

Utilization of the outside air

for heating heating and

Drinking water. Solar heat

is saved and by means of

Fans in the evaporator

the heat pump.

Conveying and swallowing wells

extract heat from the groundwater, is by evaporation

at lower and

Liquify at high temperature

released into the cycle

Pipes conduct refrigerant into the earth, is warmed there and by one

Compressor heated further there

when liquefying heat into

Heating system

benefits

Low installation effort, low operating costs, high

environmental friendliness

Low heating costs through

loose environmental energy

Low heating costs, low electricity tariffs

disadvantage

High maintenance effort

little funding, need

mostly additional

Heating options

Because of low heating temperatures

Surface heating necessary, Loss of efficiency in

falling groundwater levels

Soil quality can be efficiency

influence, high development effort

Installation of the geothermal heat pump

The most important factor in the cost of a geothermal heat pump is the chosen method of laying the plastic pipes that are used to generate heat. There are basically two methods available to owners: vertical and horizontal laying of plastic pipes. The vertically laid pipes, the so-called earth probe, are drilled as deep as possible and permitted. When laying in width, excavation is carried out to a depth of about one and a half meters. There, the pipes run in serpentine lines, similar to an underfloor heating system. It is also conceivable to lay the pipes as spiral collectors in flat baskets or trenches. Depending on the depth, a building permit may be required.

Further tips for installation:

  • The deeper the borehole, the higher the energy gain can be: a heating output of around 50 watts is achieved per meter.
  • Earth boreholes can be drilled up to 200 meters deep, the guide value for a family home is around 100 meters.
  • Earth collectors occupy about 225 to 300 square meters in a family home.
  • Moist soil can favor the absorption of heat, with sandy soils collectors must be planned more widely.
  • Geothermal heat pumps can be perfectly combined with solar systems. So you can also switch your electricity to renewable energy using a solar storage.
Erdkollektor
Erdkollektor

In heat pump heating systems, 75 percent of the energy comes from the environment.

Photo: iStock / ttsz

Development costs vary depending on the method

Depending on the development, different costs for the geothermal heat pump may arise. If the client chooses a vertical hole, the costs will fluctuate depending on the nature of the soil and depth. It should be noted that a permit must be obtained from the responsible building authorities and that very deep drilling will rarely be possible, especially in densely populated urban areas. The laying of earth collectors is usually without a permit. Although the cost of the excavation also fluctuate with the nature of the soil and the accessibility of the site, with this method only around half of the development costs can be expected.

How much are the acquisition costs for a geothermal heat pump?

The cost of purchasing a geothermal heat pump is between EUR 12, 000 and EUR 15, 000 and can vary depending on the manufacturer, efficiency and model. When buying a geothermal heat pump, two values ​​are particularly important: the annual coefficient of performance and the coefficient of performance. Both indicate the ratio of the heating energy generated and the electricity used. The coefficient of performance is also known as COP (Coefficient of Performance) and is fixed for each model. It is only meaningful if it corresponds to a DIN standard. The annual labor figure (JAZ), which indicates the economic efficiency in the specific installation case, is significantly more important for the purchase decision. The JAZ specified by manufacturers is a value that can only be achieved under ideal conditions and is usually between three and five. This means that three to five times the thermal energy could be used for each kilowatt hour. The typical JAZ for a geothermal heat pump is 4.3 to 4.5. This means that 4.3 kilowatts of heat can be generated with one kilowatt of electricity. However, these values ​​do not necessarily correspond to the real performance of a geothermal heat pump. A specialist can tell you exactly whether your desired geothermal heat pump model can actually achieve this JAZ.

The costs at a glance

Geothermal probes

about 50 euros / meter

Earth collectors

300 euros / kilowatt heating output

acquisition cost

Geothermal heat pump

8, 000 euros - 13, 000 euros

Maintenance costs

50 euros - 100 euros / per year

operating cost

600 euros - 900 euros depending on the electricity price

Payback period

about 8 - 11 years

Possible grants

In order to cover the costs for a geothermal heat pump, you can use various funding programs. KfW supports in particular with the renovation and conversion of oil heating systems to renewable energies. You can choose between a low-interest loan or a financial grant. The Federal Office of Economics and Export Control (BAFA) also supports the purchase of a highly efficient heat pump. Investment grants of up to EUR 11, 000 are possible here, depending on which heat pump you choose. Pumps that work with geothermal energy are subsidized higher than other heat pumps as standard. With clever funding, the costs for geothermal heat pumps can be significantly reduced.

Checklist: conversion to a geothermal heat pump

  • Inventory: The structural requirements for geothermal heating are decisive for the possibility of geothermal energy. It therefore makes sense to find out in advance about the possibility of drilling, the height of the groundwater level and the rock layers in the subsoil. Be sure to get a specialist company at your side who can assess the conditions on site in a professional manner.
  • Finding the right model: Which model is the right one depends on the insulation properties of your house on the one hand and the heating power required on the other. Also think about whether you want to use a geothermal heat pump with a combined air heat pump.
  • Developing individual solutions: Three factors play a role in the correct dimensioning of your geothermal heat pump: The heat demand of the house, the built-in heat pump and the geothermal probe or the geothermal collectors. If you plan too little, your pump will not run economically because you have to help out with additional types of heating.
  • Obtaining offers: The increasing demand for renewable energies has created a large market. Many - especially Northern European - manufacturers are continuously expanding and improving the technology of geothermal heat pumps. Specialist companies on site are well informed about such technological advances and can recommend the right model for you in the context of your local circumstances. By getting multiple offers, you are on the safe side to get the best value for money.

Here you can get the first information about heating with a geothermal heat pump online:

Popular by topic