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DE-102024132669-A1 - Device for utilizing hydrothermal energy

DE102024132669A1DE 102024132669 A1DE102024132669 A1DE 102024132669A1DE-102024132669-A1

Abstract

Device for utilizing hydrothermal energy with at least one first well (20) arranged adjacent to a body of water (10) and equipped for pumping bank filtrate, and a heat pump (30) connected to the at least one first well (20) by means of at least one source supply line (QVL), which is connected to at least one consumer by means of at least one consumer supply line (VVL) and at least one consumer return line (VRL), characterized in that the at least one first well (20) is arranged at a distance from the body of water (10) such that the course of the seasonal temperature fluctuations of the bank filtrate pumped from the at least one first well (20) is offset from the course of the seasonal temperature fluctuations of the body of water by at least three and at most nine months.

Inventors

  • Niels-Christian Holm

Assignees

  • Dr. Holm UG (haftungsbeschränkt) & Co. KG

Dates

Publication Date
20260513
Application Date
20241108

Claims (8)

  1. Device for utilizing hydrothermal energy comprising - at least one first well (20) arranged adjacent to a body of water (10) and designed for pumping bank filtrate, and - a heat pump (30) connected to the at least one first well (20) by means of at least one source supply line (QVL), which is connected to at least one consumer by means of at least one consumer supply line (VVL) and at least one consumer return line (VRL), characterized in that the at least one first well (20) is arranged at a distance from the body of water (10) such that the course of the seasonal temperature fluctuations of the bank filtrate pumped from the at least one first well (20) is offset from the course of the seasonal temperature fluctuations of the body of water by at least three and at most nine months.
  2. Device according to Claim 1 , characterized in that the course of the seasonal temperature fluctuations of the bank filtrate extracted from the at least one first well (20) is offset by 6 months from the course of the seasonal temperature fluctuations of the water body.
  3. Device according to one of the preceding claims, characterized in that the heat pump (30) is connected to a source return line (QRL) supplying water to the body of water (10).
  4. Device according to one of the preceding claims, characterized in that the consumer return line (VRL) has a consumer return loop (VRLS) arranged in a near-shore area of the water body (10), which transfers heat to the bank filtrate extracted from the at least one first well (20).
  5. Device according to one of the preceding claims, characterized by at least one second well (20') arranged adjacent to the water body (10), which is designed for pumping bank filtrate, wherein the at least second well (20') is arranged at a distance from the water body (10) such that the course of the seasonal temperature fluctuations of the bank filtrate pumped from the at least one second well (20) corresponds to the course of the seasonal temperature fluctuations of the water body (10), wherein the at least one second well (20') is connected to the heat pump (30) by means of at least one further source supply line (QVL').
  6. Device according to Claim 5 , characterized by a control unit supplying water from the at least one first well (20) and from the at least one second well (20') to the heat pump (30), which communicates with a sensor in each of the wells (20, 20') that detects the water temperature, wherein the control unit is configured to supply the water with the higher water temperature to the heat pump (30).
  7. Device according to one of the preceding claims, characterized by at least one third well (40) arranged between the water body (10) and the at least one first well (20), which is equipped to determine the temperature of the water flowing from the water body (10) to the first well (20), wherein the delivery rate of the water delivered from the second well (40) is determined by the water temperature measured in the third well (40).
  8. Device according to one of the claims, characterized in that the body of water (10) is a flowing body of water.

Description

The invention relates to a device for utilizing hydrothermal energy with at least one first well arranged adjacent to a body of water and equipped for pumping bank filtrate, and a heat pump connected to the at least one first well by means of at least one source supply line, which is connected to at least one consumer by means of at least one consumer supply line and at least one consumer return line. The global transformation of all forms of energy production to sustainable processes without the use of fossil fuels also affects all forms of heat production. For domestic, institutional, commercial, and industrial heating needs requiring temperatures between approximately 40 and 90 °C, heat pumps of all types will likely play the most significant role. Heat pumps extract heat from a natural medium (water, air, ground, etc.) using electricity. This process cools the medium according to the laws of thermodynamics, and the resulting heat is then transferred to another medium, usually water in the supply line of a district heating network, raising it to a higher temperature. A key aspect of all these processes is the temperature level of the source medium: the higher this temperature, the more heat can be extracted from the medium itself, and the more thermal energy (kWh of heat ) can be generated per kWh of electrical consumption by the heat pump. This conversion efficiency in kWh of heat production per kWh of electrical energy consumed by the heat pump is called the "Coefficient of Performance" (COP) and ranges from 1 to 9, depending on the pump type, medium, and the temperatures of the source and target media. A COP of 1, for example, is achieved when an electric heating element is immersed in water; then 1 kWh of electrical energy generates approximately 1 kWh of heat , the worst possible COP from an economic standpoint. The highest COP values are achieved with water as both the source and target medium and small temperature differences between these two media. It follows directly from this that it would be economically advantageous if the starting medium had as high a temperature as possible: this would result in a high COP and correspondingly little medium would be consumed. The use of water bodies of all kinds as a medium for heat extraction is now being investigated and implemented in many projects worldwide, e.g. Rhine water near Mannheim and North Sea water near Esbjerg in Denmark, where the water is extracted directly from the water body or via very close bank wells directly on the water body. However, in temperate climates, where heating demand is much higher in winter than in summer—in Germany, for example, the demand for residential and hot water heating is approximately five times higher in winter than in summer—the problem arises that almost all natural media have lower temperatures in winter than in summer. In particular, the annual temperature profile of bodies of water and nearby wells is precisely the opposite of the annual heat consumption. This problem is addressed by achieving extremely high water flow rates through heat pumps in winter, since only temperature differences of 1°C to 4°C are usable in winter, as cooling the water below 3°C is rarely, if ever, possible for both ecological and thermodynamic reasons. However, the significant disadvantages of low COPs and extremely high, and therefore ecologically problematic, water flow rates remain. The Bad Reichenhall municipal utility company has partially mitigated these disadvantages by using a groundwater heat pump supplied with groundwater from the Saalach River. At a depth of approximately 40 meters, about 50 liters of water per second are extracted from the groundwater stream and, after cooling, reintroduced about 100 meters downstream via an injection well. At the point of extraction, the water maintains a temperature of approximately 10°C to 12°C year-round, thus partially smoothing out the temperature fluctuations of the Saalach. When it is reintroduced, the temperature is between 4°C and 6°C. The heat extracted in this process can be used by the heat pump to raise the temperature to approximately 85°C. This is precisely the temperature that is intended to reach the district heating customers. This problem will be briefly illustrated using the average water temperatures compiled in Table 1 for the Treene river in the Schleswig-Holstein village of Oeversee and for wells located near the banks of the Treene over the course of a year (based on data from 1970 to 2008 interpolated with a temperature increase of 0.5 °C per decade). Table 1 shows the average Temperatures of the Treene River (A) and the water temperature of the wells near the banks (B) throughout the year. It is clearly evident that the course of the seasonal temperature fluctuations in the wells near the banks (B) largely corresponds to the course of the seasonal temperature fluctuations of the flowing water (A): Table 1 When cooling from 5 °C to 3 °C in February, only 0.1