DE102008061896A1 - Method for storing heat in earth, involves isolating individual earth probe at region, and providing thermal input in earth, so that liquid or gaseous medium heats side wall of individual earth probe - Google Patents

Abstract

The method involves assembling earth probe arrays with which an individual earth probe is isolated at a region. A thermal input is provided in the earth, so that a liquid or gaseous medium heats a side wall of the individual earth probe. A water-resistant isolator is designed by a rain proof film and a cellar floor. The thermal input is provided, so that temperature level of central probe is higher than temperature level of the probe at boundary of the earth probe arrays. A geothermal storage is initially heated by a temporary built-on solar collector.

Description

State of the art:

Heat storage itself is known and widely used. So in almost every heating system is a heat storage, which can provide hot water if needed. For the heat supply of passive houses, there are already experiments in which a large closed heat storage has been built separately to the house or in the house ( Lecture on the 5th Darmstadt Geotechnical Coloquium on March 19, 1998, Technical-economic aspects of geothermal energy storage, author Joachim T. Pape, S: 29-40, 1998 ). Disadvantage of this concept are the high construction costs, because the heat storage has a solid shell, which must be made technically complex. For this reason, with few exceptions, it is unlikely that this concept will prevail.

Next Heat accumulators with fixed sheathing are also geothermal probes known. But these are usually only in connection with heat pumps used. This process is well known and commercial offered. The concept has two disadvantages, firstly high cost of bringing a deep hole and secondly the heat pump has a high energy requirement. About 25% the heat produced must be in shape be applied by electrical energy.

In order to reduce costs, the architect Alfons Lengdobler ( Sun to Earth, passive house uses soil as a long-term heat storage, Klaus Siegele, Article from the magazine building energy consultant GEB, Jg. 4, No. 5, 2008 ) a method has been developed in which the soil under the house is heated to 60 ° C during the summer months. In the cold season, the heated soil is then used to heat the supply air. The soil is warmed up in the summer via pipes that have been laid before concreting the concrete slab. However, this method requires that there is a good thermal insulation between concrete slab and geothermal storage. A thermal insulation with the required load capacity is expensive to produce and very expensive.

Problem:

Of the in patent claim 1 specified invention is based on the problem that the production of known geothermal energy storage to is expensive and causes too high a cost.

Solution:

This Problem is with the listed in claim 1 to 14 Characteristics solved.

Achieved benefits:

One according to claim 1 constructed geothermal storage has the ability to store heat points but only low construction costs. It is known that drilling up about 20 m depth relatively easy with piling equipment performed can be. Geothermal probes are in the ground introduced, wherein the upper part of the geothermal probe thermally is isolated. This allows for a complete topside thermal Isolation of the heat storage can be omitted. In order to reduce the construction costs for a geothermal storage considerably. In the area between the geothermal probes used the soil as a thermal insulator.

Further embodiments of the invention:

is no natural water-insulating layer over the geothermal storage available, can according to claim 2 a water impermeability can be achieved.

Becomes the geothermal store is located under a basement, so This can make the required water impermeability be ensured (claim 3).

There the heat losses in the edge area of the geothermal energy storage larger than in the central area of the geothermal energy store, can by claim 4, the efficiency of the geothermal energy storage increase.

The Soil has a temperature of 8-12 ° C. in the Summer can be the temperature of the geothermal energy store according to claim 5 by using a natural source (eg a body of water) preheated to 20 ° C. About solar collectors then this temperature increase must not be generated. The required solar collector surface can be correspondingly lower be dimensioned.

The Soil has a temperature of 8-12 ° C. about a heat exchanger, the soil according to claim 6 first to appropriate external temperature level to be brought.

A Preheating the soil can also be temporary constructed heat collectors according to claim 7 done. This can already in the first year of commissioning a large geothermal field can be used.

If the geothermal storage is used together with a heat pump if necessary (patent claim 8), so the residual heat of the geothermal energy storage can be used.

at only a small amount of externally generated heat makes it according to claim 9 sense, only individual Load geothermal probes with heat. hereby becomes the usable amount of heat of the geothermal energy storage elevated.

at existing houses can geothermal probes according to claim 10 obliquely below the houses are rammed.

Walk the geothermal probes through one or more groundwater leading Layers, they must according to claim 11 are thermally insulated in the groundwater, so that the heat can not be washed away.

Around to optimize the control, the heat accumulator according to claim 12 are simulated with an electric model. The heat capacity is simulated by capacitors, the thermal resistance through resistances.

By the installation of additional temperature sensors between the Ground probes, according to claim 13, the stored Amount of heat can be better determined.

Become the ground probes according to claim 14 with a Gradients of thermal conductivity provided so The heat input can be controlled in depth become.

Embodiments of the invention:

Becomes heated water through a form-fitting introduced Ground probe, so heats the soil around the Probe slowly up. The effect increases, if the water inlet is separated from the water return in the probe and the warmer probe feed water directly to warming of the soil (Fig. 1). It makes sense that Water previously heated with Sollar collectors.

To the Protection against rain, which would wash away the heat the geothermal probes are under the floor slab of the house (Fig. 2a) or if present under the basement floor slab (Picture 2b). If there are no floor plates, then this can through a simple plastic sheet to be replaced (Figure 2c). The upper part The geothermal probe is thermally insulated, so that the Soil under the house is not heated directly. It will the soil as a thermal insulator to the floor of the house or the Earth surface used. Additionally, if needed also a cheap insulation layer on the Floor plate can be provided.

The Heat input takes place in such a way that the temperature the memory in the center is always slightly higher than in the Page ranges. Through this temperature gradient can the energy losses in the peripheral areas are reduced (Fig 3).

at existing houses can geothermal probes slammed obliquely under the houses (Fig. 4).

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited non-patent literature

• - Lecture on the 5th Darmstadt Geotechnical Coloquium on March 19, 1998, Technical-economic aspects of geothermal energy storage, author Joachim T. Pape, S: 29-40, 1998 [0001]
• - Sun to earth, passive house uses soil as a long-term heat storage, Klaus Siegele, Article from the magazine building energy consultant GEB, Jg. 4, No. 5, 2008 [0003]

Claims (14)

Method for storing heat in the earth, characterized in that a ground probe field is constructed in which the individual ground probes are insulated in the upper area, but which has no artificial insulation down and to all sides and in which the heat input into the earth so takes place that a liquid or gaseous medium heats the side walls of the individual ground probes. Method according to claim 1, characterized in that that a waterproof insulation is going up through a rain-impermeable film is built. Method according to claim 1, characterized in that that the insulation is built up through a basement floor becomes. Method according to claim 1, characterized in that that the heat input takes place so that the temperature level of the central probes is higher than that of the probes on the edge of the earth probe field. Method according to claim 1, characterized in that that the geothermal probes in the summer first through a natural source approximately on their Temperature level be brought before another charging over a heat flow takes place. Method according to claim 1, characterized in that that the geothermal probes first over a Heat exchanger to the level of ambient or be brought to an existing heat source before a further charging takes place via a heat flow. Method according to claim 1, characterized in that that the geothermal storage initially by temporarily built up solar collectors is warmed up. Method according to claim 1, characterized in that that the heat storage together with a heat pump is operated. Method according to claim 1, characterized in that that the heat input takes place so that the heat in the transitional period and in the winter months only in individual Geothermal probes is introduced. Method according to claim 1, characterized in that that the geothermal probes are inserted diagonally under an existing house become. Method according to claim 1, characterized in that that the geothermal probes are thermally isolated by one or more groundwater layers walk. Method according to claim 1, characterized in that that the control simulates using an electrical model becomes. Method according to claim 1, characterized in that that temperature sensors are placed between the ground probes. Method according to claim 1, characterized in that that the thermal conductivity of geothermal probes has a gradient, so that the heat input in the earth is depth-dependent.