RU2483255C1 - Method of seasonal use of low-potential heat of surface soil, and downhole heat exchangers for implementation of method's versions - Google Patents

Abstract

FIELD: heating.

SUBSTANCE: when implementing the method during the heating period, low-potential heat is removed from soil. Supply of liquid heat carrier is performed through soil layers by means of the main closed circulating system with closed-type vertical loops installed by means of wells. Then, heat is transferred so that it is converted by means of a heat-pump cycle to a higher temperature level to the heat supply network of the power supply site. During the non-heating period, accumulation of external heat discharges in the soil is selected and supply of heat carrier through the soil layers is changed over to an additional closed circulating system with an intermediate heat exchanger for utilisation of heat discharges, which is installed into it. When changing over from heat removal to accumulation of heat discharges, depth of heat carrier supply is changed through the soil layers from intersection level of vertical loops of one or several water-bearing soil layers to the level above the roof of upper water-bearing layer. For that purpose, some part of the loops used for heat extraction from soil is used at heat extraction and accumulation of heat discharges as per a shortened version by installing those loops as a part of the additional circulating system with the length corresponding to the second of the above levels. The rest loops are installed as a part of the main circulating system with the length corresponding to the first level. When changing over from the soil heat extraction to accumulation of heat discharges, the method allows changing heat carrier supply depth through the soil layer from the intersection level of vertical loops as a part of the main circulating system of one or several water-bearing soil layers to the level above the roof of upper water-bearing layer, thus installing vertical loops in compliance with the last level as a part of the additional circulating system, the length of which is chosen as shortened relative to that one which is chosen in compliance with the first level of length of loops of the main circulating system. The task of the seasonal change of levels is solved either by using known structural designs with wells of various depths as a part of loops, or based on the proposed design of the downhole heat exchanger.

EFFECT: more effective seasonal change of levels.

2 cl

Description

The field of technology.

The present invention relates to technologies and means of autonomous heating in various modes (low temperature, medium temperature), hot water supply and cooling for buildings under construction and reconstructed for various purposes (residential sector, office buildings, healthcare facilities, education, etc.) with integrated use, based on closed-hole well circulation systems and heat pumps, low-potential renewable heat sources from the environment (upper, to a depth of 100 -200 m, soil layers) and increasing their potential for thermal discharges of technogenic origin.

The level of technology.

The analogues of the present invention include a method of using low-grade heat of near-surface soil intended for hot water supply (DHW) of a multi-storey residential building, implemented according to functional diagrams, a graphic image of which is shown in Figs. 3-20 and 3-24 of the color tab between p. 160 and 161 monographs: Vasiliev G.P. Heat and cold supply of buildings and structures using low-potential thermal energy of the surface layers of the Earth. - M .: Publishing House "Border", 2006.

Here, low-potential heat of the upper (up to a depth of 100-200 m) soil layers is used here as renewable geothermal energy, extracted before applying for thermal transformation in heat pumps using downhole heat exchangers (STO). Secondary energy resources are used as a technogenic source of thermal discharges in SRTs - heat discharged with ventilation exhausts, which is disposed of during the year and added to the soil heat extracted using SRTs.

The method is carried out by selecting low-grade heat from the soil by supplying an anti-freezing liquid coolant (e.g. antifreeze) through the soil layers using a closed circulation system, in which closed circuits are installed using wells and form coaxial downhole heat exchangers of almost the same length (Fig. 3-22, p.115 and fig. 3-23, p.116 from the indicated monograph), with the help of which heat is taken from the surrounding soil and the transfer of the heat carrier so heated I’m going to a heat pump (or a cascade of heat pumps), where they produce thermal transformation of the extracted heat to a higher temperature level required by the consumer. At the same time, during the periods of the necessary maximum heating of water (winter mode) in the hot water supply network connected to the heat pump (VT) condenser, the heat carrier is additionally heated using an intermediate air-to-water heat exchanger installed in the area between the heat pumps and the exits from the service station, connected by the reverse (air) side with the exhaust line of the facility’s ventilation system, as a result of which secondary energy resources (heat of ventilation emissions are used in addition to the soil heat in the technological scheme ) In the summer DHW mode, the excess heat of ventilation blowouts generated, which is continued to circulate through the intermediate heat exchanger and vertical borehole coolant circuits, is discharged and accumulated in the ground, thereby contributing to the restoration of the thermal regime of the wells, along with natural factors that manifest themselves mainly in the form direct solar radiation and geothermal heat flux. As a result, the method provides the required year-round heat supply for the object to supply hot water.

The disadvantages of this method are determined by the following circumstances. Since the DHW season lasts almost the entire year (with short breaks for testing and repair), in this scheme, the soil heat collection system does not have the ability to optimally support the restoration of the thermal regime of wells from natural factors (variable solar radiation and weak geothermal flow at such depths of wells), since this recovery component is more effective during periods of termination of heat extraction from the soil (in this scheme, these are periods of connecting the intermediate heat exchange openings to the coolant supply line through the expansion tank). And if in relation to the heat capacities implemented in the hot water supply mode, the potential for thermal venting of ventilation is sufficient as compensating support for the restoration of the thermal regime of wells in the context of the year, then with more intense heat loads, characteristic, for example, for heating, including heat consumption of the facility and its ventilation , thermal deficit of wells, as shown by modeling and experiments on heat transfer in the soil, will accumulate significantly during at least 10-15 heating seasons. As confirmation of this circumstance, for example, graphic dependencies reflecting this dynamics are obtained obtained in relation to the conditions of the central regions of Russia by calculation according to the Swedish method, repeatedly tested in world practice (the journal "Heat Supply News", 2007, No. 10, p. 26-33 )

In addition, the geological section shown on the left in Figs. 3-23 (p. 116 of the indicated monograph) shows: despite the possibility of increasing heat removal from 1 linear meter. m STO at the intersection of the outer surface of the STO, starting from a depth of 18 m, an aquifer 5 m thick (fine-grained aquifer sand), due to the well-known effect - the thermal contribution of the groundwater filtration rate, to periods of transition from heat extraction to discharge measured in practice, as follows from the text on p. 119 of the monograph, “actually coinciding with the beginnings and endings of the heating seasons”, the situation favorable for heat removal will be replaced by an increase in heat losses during accumulation of heat discharges, due to eivaniya discharged in this region the heat flowing around SRT groundwater. Therefore, in the case of using a similar technological scheme at sites containing geological sections of the soil with a developed groundwater flow, especially when trying to additionally apply it to provide thermal loads of heating, even continuous accumulation of vented exhaust heat in the soil during the year, accompanied by heat loss in zone of aquifers may not be effective enough to compensate for accumulated from year to year, during periods of heating loads, heat shortage wells.

These circumstances either require a significant increase in the length or number of service stations when designing a soil heat collection system associated with an increase in the cost of their construction, or, taking into account the incomplete temperature recovery of wells, lead to an economically unjustified reduction in the service life of the heat collection system, besides not allowing for such a scheme effectively implement heating modes in conditions of prolonged heating seasons, as well as other consumer functions, for example, combine in the interspot During the hot period, restoration of the wells with their use during the hot period for direct (without air conditioning) cooling of the premises of the power supply facility.

This limits the technological capabilities of the known method, increases the payback period of systems for its implementation, and also reduces the possibility of choosing effective sections of the territory for building the underground part of the systems.

Closest to the proposed invention by its technical nature is a method for seasonal use of low-grade heat of near-surface soil, according to which the heating loads are effectively ensured by dividing the stages of taking heat from the soil and accumulating waste heat in the soil during the year and periodically changing over the years, the combination of these stages carried out with the support of the natural restoration of the thermal regime of heat collection wells in the inter-heating period by switching the load PP of vertical soil circuits (downhole heat exchangers) of the same length at the end of the heating season from the main closed circulation system (WCC), which serves to take the soil heat, to an additional WCC passing through an intermediate heat exchanger to recover heat from ventilation blowouts during inter-heating periods, and the technological capabilities of the method in the operation period of this WCC has been expanded by the function of cooling the premises of the power supply facility directly from the wells (Geothermische Energie - 2005. - No. 49. - diagram on p.31, fig. 4).

In accordance with this method, adopted as a prototype of the present invention, in the heating season, low-grade heat is selected from the soil by supplying liquid coolant through the soil layers using a closed circulation system with closed vertical circuits installed in its composition, and the following heat transfer, with its conversion to a higher temperature level by using the heat pump cycle, to the heat supply network of the energy supply facility And in interheating transition to the accumulation in soil of external thermal discharges, converting the supply of coolant through the soil layers on additional closed circulation system installed in its composition intercooler utilization of external thermal discharges. The source of thermal discharges (vent exhaust heat) used in this method has a relatively low potential, which allows, if necessary, combining thermal restoration of the soil with the possibility of simultaneous cooling of the facility premises supplied during this period through the borehole circuits and an intermediate heat exchanger (water-air type) with a heat carrier.

This technology differs from the previously considered analogue in its expanded technological capabilities due to the functions of heating and cooling the premises, however, it is supplied, as in the analogue, with the supply of heat carrier during the seasonal change of the stages of heat selection and storage by a group of heat exchangers of the same length (through the same soil layers), for the reasons discussed above, excludes the effective implementation of both stages with the initial selection of sites with an achievable maximum level of continuous heat removal from 1 linear meter. m STO, determined including the thermal contribution of the rate of groundwater filtration in the areas around which they flow around the surface of the STO. The economic justification for the appropriateness of such a choice is the possibility of reducing the total length of service stations included in the soil heat collection system, which is confirmed by calculations and practice, associated with an increase in the specific heat output (W / linear m), according to various estimates, to 17-30%, which reduces costs for the construction of service stations (1. Theoretische und Praktische Untersuchungen zur Auslegung von Erdwarmesonden im Lockergestein unter Besonderer Berucksichtigung der Geologisch - Hydrogeologischen Gegebenheiten Nord - Ost - Deutschlands // IZW - Bericht, FIZ, Karlsruhe 1997, No. 5 - 1997. 2. Optimization of technical and geological and economic solutions in the development the introduction in Russia of geothermal heating technology heating // news -. 2010, №5, S.25-32).

Provided that the complex of borehole loops of the same length is laid with the aim of increased heat removal through the zone favorable for heat removal, that is, with the intersection of aquifers, switching the coolant supply from the main to the additional circulation system to conduct the accumulation of heat sinks will result in heat accumulated at the same time due to the influx from the source of effluents into an area extending from the surface of the Earth to the level of the upper aquifer, while moving the coolant deeper than th zone will be partially or completely lost as a result of dispersion in the surface portions vertical contour streamlined groundwater.

And vice versa, in the case of choosing sections with the depths of the SRT of the same length above the roof of the upper aquifer, that is, in the zone of an absent or underdeveloped groundwater flow, when implementing the known method, promising conditions in this case for accumulation (several times reduction in heat loss) will be accompanied , with the subsequent seasonal transition to the selection of heat from the same service stations, with low specific heat removal (by 1 linear meter of service station), since the thermal effect is lower than those located, significant in power and speed the filtration of aquifers to the higher SRTs manifests itself to a much lesser extent, being limited only by the increase in thermal conductivity of the rocks that promotes heat removal as a result of their water saturation in the area from the bottom of each well to the level of fluid around the wells.

Thus, the method does not allow economically profitable to use for the construction of borehole soil systems widespread, for example, in the central regions of Russia, areas where the depth of the geological section is favorable either for heat removal or for accumulation of layers of surface soil, as a rule, replace each other , excluding the possibility of carrying out each of these stages carried out seasonally at maximum efficiency, due to the use of vertical ground loops of the same length. The need to increase the total length or number of service stations associated with this circumstance when designing soil systems can lead to a significant increase in construction costs and payback periods for geothermal projects.

In addition, it is important to take into account one more advantage of using geological sections, including aquifers, which consists in increasing due to thermal support provided by groundwater, 2-3 times the annual amount of heat extracted (kWh / running meter per year) , and, consequently, the permissible duration of the selection of thermal energy from each linear meter of service stations in a year, which is limited by a drop in the soil temperature to a value close to its freezing, or by a decrease in the KPTN outside the effective operating values. Such accounting is especially needed due to the need to reduce investment in geothermal projects in the regions of Russia, most of which are characterized by long heating seasons (more than 4000-5000 hours per year).

The purpose of the present invention is due to the integrated use in the method of factors such as thermal support of moving groundwater, minimization of heat loss of accumulated heat in the zone of undeveloped water flow, combining during accumulation of heat discharges of different potentials, to ensure the expansion of technological capabilities, including the effective implementation of the heating function for long heating seasons, while reducing operating costs for the use of low potential soil energy resources, and - a decrease in the duration of the growing season with the costs of the construction of borehole heat exchanger systems (SRT). To do this, it is necessary to provide for the possibility, without increasing the number of service stations in the well system, to vary seasonally, with the appropriate choice of the geological site, the coolant supply zone through the soil layers: from the zone that contributes to the maximum geothermal return in the heating season, to the zone effective to preserve accumulated in the soil heat during the inter-heating period.

This goal is achieved by the fact that in the known method of seasonal use of low-grade heat of near-surface soil, in which during the heating season low-grade heat is taken from the ground by supplying liquid coolant through the soil layers using the main closed circulation system with vertical wells installed in it, using wells closed circuits, and - subsequent heat transfer, with its conversion by using the heat pump cycle to a higher temperature level, to the heat supply network of the energy supply facility, and in the inter-heating period they switch to accumulation of external thermal discharges in the soil, transferring the heat carrier through the soil layers to an additional closed circulation system with an intermediate heat exchanger disposed of heat discharges installed in its composition, according to the invention, during the transition from heat removal to accumulation of thermal discharges, the depth of coolant supply through the soil layers changes from the level of intersection with vertical ntours of one or several aquifers of soil to a level above the roof of the upper aquifer, for which some of the circuits used to take heat from the soil are used when taking heat and accumulating heat discharges according to a shortened version, by installing these circuits as part of an additional circulation system with a length corresponding to the second of these levels, while the remaining circuits are installed in the main circulation system with a length corresponding to the first level.

Within the framework of the above defining claim, process variants are proposed based on two different approaches to changing the coolant supply depth: either due to the proposed combinations in the soil system of groups of well heat exchangers of known standard designs, with different lengths of heat exchangers in the groups, or due to the use in some of the variants of the method of downhole heat exchangers proposed in the framework of the invention.

According to one of the options that implement the first approach, an additional difference of the method is that when the soil heat is taken into the heating season, the heat carrier is supplied simultaneously through the main and additional circulation systems using downhole heat exchangers based on combinations of long and shortened vertical circuits with wells of different different depths , and during the accumulation of thermal discharges in the soil during the inter-heating season, the coolant is supplied only through a circulating system using borehole heat exchangers of the same length based on a combination of shortened circuits with wells of the corresponding depth, while long heat exchangers of the same length formed by another combination in the main circulation system are placed in a row perpendicular to the movement of groundwater in aquifers, at a distance from each other at least 6-10 m, and in pairs with shortened heat exchangers placed in a row in the composition of the additional circulation system, displacing relative to the latter in the direction of groundwater movement at a distance selected by the speed of water movement above the aquifers, in the range of 3-5 m.

Another difference is determined by the variant of the method in which, when using vertical circuits in the form of U-shaped plastic tubes for heat removal and accumulation of thermal discharges, the contours of different lengths used as part of the main and additional circulation systems are placed in pairs inside each well, the depth of which is selected according to the long contour, while the selection of heat using the primary and secondary circulation systems and the accumulation of thermal discharges are performed using the same wells depth forming, with a pair of circuits of different lengths and a heat-conducting filler placed in them, downhole heat exchangers of the same length.

Another additional difference of the method, as an option, is that when the depth of the roof of the upper aquifer does not exceed 20-40 m, shortened borehole heat exchangers are used with an increased specific heat transfer surface of relatively long borehole heat exchangers, by using different heat exchangers for selection and storage design, installing, for example, in the main circulation system heat exchangers with vertical circuits in the form of U-shaped plastic tubes and in an additional circulation system heat exchangers in the form of a vertical coaxial-type circuit made using a well of increased diameter, relatively long heat exchangers.

The following additional difference, implemented in relation to all previous variants of the method, is determined by the fact that when accumulating heat discharges in the soil, shortened circuits are used with the possibility of connecting an additional circulation system through the main or additional intermediate heat exchanger disposing heat exchanger in it, an additional source discharges, including - with a potential increased relative to the main source, for example, heat surplus taken away during the inter-heating period by the cogeneration unit, setting the flow rate or flow rate of the coolant through a shortened circuit in accordance with the selected share of the potential consumption of the additional source through an intermediate heat exchanger, or by optimization during design the number of shortened contours of typical designs, or by applying a pairwise modified version long and shortened contours in the borehole of the downhole heat exchanger, while the flow through the additional circulation system is controlled in accordance with possible changes in this fraction during the interheating period.

Closest to the device proposed in the framework of the invention for solving this problem is a well heat exchanger selected as a prototype for seasonal use of low-grade heat of near-surface soil, comprising a well with at least two vertical circuits for supplying a heat-transfer fluid installed in a heat-conducting filler of a well, made in in the form of U-shaped plastic tubes, the input and output branches of which are used to connect to the equipped circulation m closed system pump supplying coolant through the heat pump evaporator, a condenser connected to its power supply from the heat supply network object. At the same time, the outlet branches of the tubes, before entering the evaporator, can be switched via jumpers and an intermediate heat exchanger to an additional circulating closed system connected to a source of heat discharges (Geothermische Energie, 2000, No. 28/29, p. 26, Fig. 6). In the selected prototype, these are the thermal emissions of the equipment operating at the power supply facility (computers, household appliances, etc.) that enter the inter-heating period for accumulation into the borehole downhole system (consists of the SRT of the above construction, in the amount of 154 pcs., 70 m long each located with a step that is optimal for such a large system - 5 m).

The disadvantage of this device is the fact that the complexes used in downhole heat exchangers of two U-shaped vertical circuits of the same length when placing wells in areas that increase heat removal due to the establishment of service stations with the intersection of aquifers, after connecting to the accumulation of thermal discharges to an additional the circulation system interacting with the intermediate heat exchanger will lead, as noted above, with the designed equal length of the circuits to initial losses of accumulated heat in zones of intersection of the aquifers by the contours, due to heat dissipation by the groundwater flowing around the SRT. Thus, when using such a design, the integrated efficiency of seasonally changing heat extraction and storage processes is reduced, which ultimately leads to an increase in the length or number of service stations during the development of design estimates, increased volumes of drilling operations, which significantly worsen in conjunction with an increase in the cost of installation of the service station economic indicators of the construction and operation of borehole soil systems (increased investment and payback periods, especially in relation to long-term heating seasons).

Therefore, an additional objective of the invention is to solve the problem of further improving the economic indicators of the proposed method by creating a design of a downhole heat exchanger that implements, within the framework of some variants of the method and certain geological conditions, a periodic change in the coolant supply zones based on a common well with independently functioning circulating systems in it, which will ensure integrated efficiency seasonally conducted stages of the selection and storage of heat at a reduced count HONORS ground heat exchangers in the well system.

This goal is achieved by the fact that in the borehole heat exchanger proposed for implementing the method for seasonal use of low-grade heat of near-surface soil containing a well with at least two vertical circuits for supplying liquid heat carrier installed in the heat-conducting filler of the well, made in the form of loops from U-shaped plastic tubes of the same diameter, the input and output branches of which are included in the closed coolant supply system equipped with a circulation pump cut the evaporator of the heat pump connected by its condenser to the heat supply network of the energy supply facility, while the output branches of the tubes before entering the evaporator are connected through jumpers and an intermediate heat exchanger for the utilization of heat discharges to an external source of discharges, according to the invention, loop loops formed by tubes are made with different lengths, at the length of the loop of the long contour and the corresponding well depth are selected taking into account the intersection of the contour and the well, at least one aquifer located in the ground, and the length of the loop of the shortened circuit is selected with the possibility of placing the circuit above the roof level of the upper aquifer, while the input and output branches of the long circuit tube are included in the main closed coolant supply system, the branches of the shortened circuit tube are connected to another circulated a pump of an additional closed coolant supply system connected through a jumper at the outlet of the shortened circuit with the input of the heat pump evaporator the wasp and the water side of an intermediate heat exchanger, selected water-air version, with the possibility of joint or separate use through the jumpers of the main and additional closed systems in the heating season to select ground heat and transfer heat fluxes through both systems to the heat pump evaporator, and the shortened circuit is made with the possibility of connecting through a jumper of supply of the liquid coolant soil cooled as a result of heat extraction in the inter-heating period to the exhaust line of the source and discharges heat in the form of exhaust heat the ventilation air from the object of power supply connected via the other side of the intermediate heat exchanger with the supply line after the exhaust air heat exchanger for cooling the object space.

An additional feature of the device is that the shortened vertical circuit is made with the possibility of connecting through a jumper to an additional source of thermal discharges, including with an increased thermal potential relative to the main source, for example, in the form of thermal surplus discharged during the inter-heating season from the one serving this or other objects power supply of the cogeneration unit, and an additional closed system for supplying coolant is equipped with an additional intermediate heat exchanger of heat discharges of the selected water-water version installed in the system with connection of one of its sides to the input and output branches of the loop of a shortened circuit, through the jumpers, of the other side to an additional source of thermal discharges, while the number of shortened vertical contours in the well, the ratio of diameters established in tubes of long and shortened contours and the diameter of the well corresponding to these parameters are selected taking into account the set, in accordance with the possible share of consumption potential of an additional source through an additional intermediate heat exchanger, flow parameters or linear flow rate of the coolant through a shortened circuit.

A brief description of the drawings. Figure 1 presents the implementation diagram of the proposed method for the seasonal use of low-grade heat of near-surface soil according to the variant with the accumulation of heat of exhaust ventilation in the soil, shown during the heating season and carried out on the example of borehole heat exchangers (STO) of coaxial design. The scheme involves a multi-well system in the form of 2 groups of service stations of different lengths, with the arrangement of long and shortened service stations in 2 rows relative to each other, which during the indicated period implements the joint selection of thermal energy from the soil by both groups with its subsequent thermal transformation in the heat pump as applied to the low-temperature heating mode, which has the potential to implement an additional consumer function - the use of wells in the inter-heating period to cool the premises of an energy-supplied facility.

Figures 2 and 3 show fragments of other well systems that can be used according to the general scheme of Fig. 1, characterized by the use of other standard SRT versions in the method: with vertical contours doubled in wells of different lengths from U-shaped plastic tubes (2 a contour of the same length, with the same tube diameter, in each well - Fig. 2), or a combination of two different typical versions of service stations in different groups (Fig. 3), used in a specific geological situation (insufficient depth of the upper aquifer layer - 2A in figure 3) to increase the specific heat transfer surface of the SRT at the stage of accumulation of thermal discharges in the soil.

Figure 4 shows a fragment of the downhole system and proposed, according to the invention, the design of the service station for the implementation of another variant of the method, which allows to carry out, in the presence of a source of waste heat in the form of vent exhausts or about the same potential, the steps of heat extraction and accumulation of thermal discharges in combining two vertical a contour of different lengths from U-shaped tubes of the same diameter to the well (neighboring SRTs are conventionally shown by axial lines at a distance of h ₁ ).

In Fig. 5, a diagram of an embodiment of the method is separately given if it is possible to use a source of heat discharges of increased potential (heat surplus from KGU) next to the object, depicted in relation to the implementation of the medium temperature heating mode based on another proposed in accordance with the invention and presented in Fig. 5, design of HUNDRED, for example, the use of a single HUNDRED, sufficient, for example, for maintenance (heating + DHW) of an object with low heat demand (cottage, etc.).

The implementation of the invention. Depending on the specific geological conditions, in particular, the depth of the roof of the upper aquifers relative to the Earth’s surface, the thickness of aquifers (hereinafter referred to as significant aquifers, the layers are at least several meters thick) and the rates of groundwater filtration, species and potentials of available heat discharges, as well as various purposes and heat requirements of energy-supplying facilities, building areas of a downhole heat extraction / storage system, autonomous schemes power supply facilities, sometimes not only with heat and cold, but also with electricity (scheme with cogeneration), the proposed method is carried out in different ways.

In some variants of the method, the defining feature underlying the invention — the seasonal change of the zones of the geological section by changing the depth of the coolant supply during the transition from heat selection to the accumulation of thermal discharges in the soil and vice versa — is realized as a result of optimization of the well system due to the use of different composition in its composition cascades (groups) of vertical contours using the same depth wells in each cascade. The solution in this technological direction is obtained on the basis of standard technical means, namely: STO of known designs (Figs. 1, 2) or a combination of different types of designs (Fig. 3). According to one of the proposed variants of the method, a different approach is implemented - using the design of the SRT changed as part of the invention (Fig. 4). Variants of the method with a source of waste heat of increased potential can be realized both by optimizing the number of service stations when designing well systems similar to those shown in Figs. 1-4, and by connecting instead of a circuit with a low power source or in conjunction with it (for example, when for different floors of the building designed different heating modes) options with additionally changed, relative to figure 4, the construction of the service station (figure 5).

According to the first direction of the method, mainly associated with the use of multi-well soil systems, the following elements are involved in the scheme of the method according to Fig. 1.

In the section of geological section 1, which includes at least one aquifer (in the example in Fig. 1, complex 2 of two aquifers 2a and 2b), along the central axes placed in two rows of cased wells 3 and 4, with different depths in the rows, pipes of the corresponding length are installed (on the circled fragment of FIG. 1, the central pipe and the annular space formed with its help are shown in section, arrows indicate the circulation of the coolant). Pipes in combination with wells 3 and 4 form in this case two groups of vertical circuits 5 and 6 of a closed type, in the form of STO coaxial design, with the same length within each row, but different in rows (Fig. 1). In order to achieve the required for the implementation of the method different arrangement of the contours relative to the level of occurrence of aquifers, the group of longer wells 3 and contours 5 is made with a length that ensures that they intersect the complex of aquifer layers 2a and 2b to the bottom level of the complex or slightly lower, and the group of shortened wells 4 with contours 6 — the length corresponding to their location slightly above the roof of the upper aquifer 2a, that is, outside the zone of movement and the associated thermal influence of groundwater. A similar arrangement of the SRT arrangement can be provided in relation to the contours of U-shaped plastic tubes (in the fragment in Fig. 2, each tube forms a separate contour, the contours of the same length are doubled in the well).

In this case, according to the variants of the method, the long and shortened circuits and the corresponding SRTs are arranged in the borehole system or in the most well-known and most common method in practice, that is, at an equal distance (with the same pitch relative to each other, that is, in Fig. 1: h = N), which, according to the recommendations, is at least 6-10 m (in order to reduce the mutual thermal effect of the SRT during heat removal from the soil, while with increasing design quantity of the SRT in the well system, the distance increases), or with a reduced, for the possibility of transferring during the heating period part of the accumulated heat from a row of shortened circuits 6, in accordance with the direction of groundwater movement, to an adjacent row of long circuits 5. The offset of the rows relative to each other is set in accordance with the often weak groundwater flow in the zone above of the aquifer 2a, which in linear velocity, as a rule, is 1-2 orders of magnitude lower (in Fig.1-2, possible low-power aquifers in this zone are not conventionally shown) of a more rapid movement of water in the lower layers (direction shown by arrow). Therefore, choosing H in the previous dimensions, h is changed when designing to h ₁ , where h _{1 is} set, taking into account the generally practiced weak (below 10 ^-7 m / s) filtration rates in the upper layers, for the considered central regions of Russia, as a rule constituting 0.01-0.025 m per day. Based on the specified range and taking into account the possible displacement of the accumulated flow for the inter-heating period (5 months) calculated from it from a number of shortened circuits 6 in the direction of groundwater movement, h _{1 is} set to 3-5 m, while the highest value (5 m) corresponds to the upper the limit of this speed range (in terms of - no more than 10 m per year). Distances were also selected on the basis of confirming experiments on accumulation under conditions of poorly manifested influence of groundwater, in medium (36 service stations with contours of 30 m at a distance of 3 m, from twin U-shaped tubes) and large (154 service stations with contours of 70 m per 5 m distance, of the same design) downhole systems, thermal discharges of small and high potential, respectively - heat emissions from operating household equipment or heat surplus from KSU (1. Nahwarmesystem mit Erdsondenwarmespeicher in Greusenheim. / R. Barthel und and. // Geothermische Fachtagung, Straubing: 12-15 Mai 1998 - p. 531- 538. 2. "Geothermische Energie", 2000, No. 28/29. - p.23-27).

To supply a liquid non-freezing coolant (for example, antifreeze) through the soil layers, the long circuits 5, when coaxially designed, are integrated with the help of central pipes and annular space (shown in the fragment circled in figure 1) into the main closed circulation system (CCC) equipped with pump 7 8, having the ability to connect (using jumpers 9, 10, 11a) to the input and output of the evaporator 12 of the heat pump 13, connected via a condenser 14 to the water heating network 15, equipped with a pump 16 and a peak heater 17 (on opitelnye network capacity and the required low temperature for underfloor heating pipework are not shown).

Shortened circuits 6 are likewise integrated into an additional CCC 19 equipped with pump 18, which can be connected either (via jumpers 10, 11b, 20, 21) to the inlet and outlet of evaporator 12, or (via jumper 22, with jumper 21 closed) to the water side an intermediate heat exchanger 23 for utilization of thermal discharges connected by the other (air) side through a jumper 24 with an exhaust unit 25 of the ventilation system of an energy-supplying object (not shown conditionally). Block 25 also has the ability to connect through the jumper 26 to the recuperative heat exchanger 27 of the line to return the heat of ventilation exhausts to the heating load (not shown conditionally). In the general scheme of the method (Fig. 1), jumpers 28, 29, 30, 31 are also involved, while the last two serve to transfer air coming from block 25 through the heat exchanger 23 or to the atmosphere through the jumper 30 (according to an embodiment of the function restoration of the thermal regime of the soil when cooling the premises of an energy-supplying facility is unnecessary), or through jumper 31 to the air distribution unit 32 for implementation, together with thermal restoration of the soil, an additional function - cooling the premises of the facility directly from the wells, to orye by selection of their heat to interheating period acquired reduced temperature.

In the case of applying in a circuit similar to FIG. 1, another standard design of SRT, in the form of loops placed using heat-conducting filler in wells 3 and 4 (FIG. 2), each vertically installed U-shaped plastic tube has the same length in double loops and performs the role of a separate circuit inside the well, having input and output branches (in Fig. 2, the filler of the wells is highlighted in gray, and the tubular loops are shown conditionally, each loop is in the form of a thickened line, while the contour is of the same length for the convenience of the approaches to their consideration as part of the general scheme in Fig. 1 are denoted by the same position (for example, in Fig. 2, two circuits 5 and two circuits 6)). In this case, the connection of long and shortened circuits to the main and additional ZCC is carried out by combining the double loops at the input and output with common pipes. At the same time, the final elbows of the tubes of shortened vertical contours 6 and the bottom of the well 4 are placed by analogy with Fig. 1, above the roof of the upper aquifer 2a (Fig. 2), that is, outside the zone of significant groundwater movement, and long contours 5 are placed taking into account the intersection them and well 3 of one or more aquifers of sufficient power (in the example of FIG. 2, layers 2a and 2b).

Provided that the building under construction is provided with thermal protection in accordance with modern building codes or after reconstruction of the existing building to these standards, which allows us to limit ourselves to low-temperature heating in many projects, as well as to equip the building with a supply and exhaust ventilation system, taking into account the study of the geological section in the place the location of the object, the method according to the General scheme presented in figure 1, is as follows.

With the beginning of the first heating season, with the help of circulation pumps 7 and 18 (operating pumps in the diagram are conventionally shown as black triangles), at the same time along the main 8 and additional 19 closed circulation systems (CCC), a liquid coolant (for example, antifreeze) under pressures N ₁ and N ₂ are fed for the selection of soil heat in long 5 and 6 shortened vertical circuits, either of coaxial design (Fig. 1) or in a circuit of U-shaped plastic tubes (Fig. 2). Next, heated in the annulus (shown in the fragment in figure 1) or in U-shaped tubes (figure 2), due to the heat of the surrounding soil, the coolant is passed, mixing flows from the central heating station 8 and 19, through the evaporator 12 of the electric heat pump 13 (with open jumpers 9, 10, 11a, 11b, 20, 21, 28 and closed jumpers 22, 29), transferring part of the heat in the evaporator to a low-boiling working fluid (refrigerant), compressed after evaporation by the compressor of the heat pump. As a result of compression, the refrigerant vapor is heated, transforming the low-grade heat of the soil supplied with the coolant flow to a higher temperature level. This level is used to heat the heating water circulating with the pump 16 through the condenser 14 of the heat pump and the low-temperature (e.g. floor) heating network 15 to a certain intermediate temperature (40 ° C in figure 1), determined by the recommended effective temperature difference in the evaporator and a capacitor (usually not more than 30-50 ° C). After exiting the evaporator 12, the coolant is again divided into streams flowing through the CCS 8 and 19 according to the SRT groups of different lengths. If necessary, on the coldest day, using a peak heater 17, for example, electric, additional heating of the water coming from the condenser 14 to the calculated temperature of the low-temperature heating mode is carried out (in Fig. 1, to 45 ° C).

At the same time, during the first and subsequent heating seasons, the heat of vented ventilation air in the heated object is utilized according to the scheme preferred during these periods, directing the air with the jumpers 24 and 26 closed and open respectively to the heat exchanger 27, returning most of the heat through it to the system’s supply line ventilation of the facility (using recovery in the heating season, they return more heat in relation to the version with discharge into the wells: on modern heat exchangers - from 70 to 90%).

When a coolant, cooled by passing through a evaporator of a heat pump by 3-5 ° C, is supplied to the service station, heat extraction from the soil during the first heating season and then is accompanied by a gradual decrease in the soil temperature, which leads to a coolant temperature approaching the minimum temperature at the end of the season the permissible value for the efficient operation of the heat pump (in the example of figure 1 at the end of the first season, the temperature before entering the evaporator 12 is limited by the recommended limit value indicated brackets - -5 ° C).

In order to prevent a further drop in the temperature of the coolant in subsequent seasons (associated with the stage of heat extraction from the soil, for example, with insufficient possibilities of additional heat removal caused by relatively low groundwater filtration rates during the heating season, and, in the inter-heating period, by the possible incomplete thermal restoration of the soil from other natural factors), after the end of the first heating season, thermal discharges of ventilation are sent to accumulation in the ground (in the service station). To minimize the heat loss of accumulated heat during the inter-heating period with its beginning, the main ZCC 8 with long borehole loops 5 crossing the aquiferous soil (2a and 2b in Figs. 1, 2) is turned off using jumpers 10, 11a, and the depth of the coolant supply is reduced to the level of the zone located above the roof of the upper aquifer 2a, for which, turning off the pump 7, the coolant is circulated with the closed jumpers 10, 11a, 21, 28 through the open jumpers 22, 29, 11b only through an additional ZCC 19 with shortened coaxes 6 real or loop type (1, 2), bypassing the heat pump 13 during this period.

Thus, the coolant after pumping through the shortened circuit 6 is fed to the water side of the intermediate heat exchanger 23, where they are additionally heated due to the difference between the temperatures of the coolant and the warmer emissions of the removed ventilation air, switching for this by opening the jumper 24 and closing 26, the air supply from the exhaust unit 25 of the ventilation system to the intermediate heat exchanger 23. Next, the coolant is fed, bypassing the heat pump 13, again to circuit 6, where during the interheating IRS, by the circulation of coolant and thus storage of waste heat, heat recovery occurs, passing in a small display of lot relative to the initial state (before the first heating season). As calculations using computer simulation according to the well-known methodology (“News of Heat Supply”, 2007, No. 10, p. 26-33) show, using the example of depths up to 100 m as applied to the initial soil temperatures in the Yaroslavl region (6-8 ° С) in operating conditions of typical ventilation with the discharge of heat of ventilation blowouts during the inter-heating period, in the absence or specified weak movement of groundwater in the zone above the simulated aquifer 2a in the range of indicated speeds (0.01-0.025 m / day), the initial one for the beginning of the next heating Season coolant temperature at the outlet of the downhole circuits 6 through multiple circulations through ZTSS 19 is output for the period (5 months) at levels of 10-12 ° C.

Simultaneously with the beginning of accumulation, due to the movement of groundwater, the priority direction of propagation of the front of the accumulated heat flux is set, as a result of which a gradual slow shift of the accumulated heat from a series of shortened circuits 6 to the opposite long circuits 5 begins to cover, according to the distance h selected according to the flow velocity ₁ , part of the heat flux by the beginning of the heating season, long circuits 5, as a result of which heat recovery is supported part of long service stations, part of the accumulated heat from shortened service stations.

Therefore, in the heating season, the lower part of the long service stations is heated mainly due to the thermal effect of relatively fast moving groundwater, and the upper part is due to the part of the accumulated heat coming from the shortened service stations that comes with slowly moving water (increased heat transfer also contributes to it, due to standing fluid around the wells due to backwater below the aquifers, soil thermal conductivity). At the same time, part of the heat accumulated in the upper zone of the geological section near the end of the inter-heating period and stored in the vicinity of shortened service stations due to low filtration rates is also used during the heating season in a combined flow from long and shortened service stations to the heat pump, in order to increase geothermal heat transfer.

After passing through the heat exchanger 23, the vented ventilation air cooled in the heat exchanger with a lower-temperature liquid coolant coming from the shortened circuits 6 is either discharged into the atmosphere by opening the jumper 30 and closing the jumper 31, or in the hot period, performing the opposite actions with these jumpers, use more economically viable option, providing the expansion of technological capabilities of the method, by supplying air during this period to the distribution block 32 for cooling the premises effectiveness to the object.

In the next heating season, they again include the joint supply of the coolant along the main and additional ZTSS 8 and 19 with the downhole structures built into them, according to Fig. 1 or Fig. 2, and provide, taking into account the situations of reduced heat loss during accumulation through the shortened circuit, ( there is no influence of flowing water) and the possibility of providing thermal support for moving groundwater at the stage of heat extraction, supplemented in the upper zone of long service stations by w accumulated by the flow of the mixed flow optimal coolant temperature at the inlet of the heat pump evaporator. Providing at the beginning of the second and subsequent heating seasons due to preliminary accumulation with a minimum of heat loss of at least 10-12 ° C, at the end of the seasons, as shown in figure 1, get about 5 ° C. This is 10 ° C higher than the value for the first season , shown in Fig. 1 in parentheses and obtained without preliminary accumulation of heat exhaust ventilation. If possible, in a particular situation, the implementation of the method with the sequence of stages for the selection and storage of heat changed in the first season, the indicated temperature indicators will only improve.

When the temperature of the coolant at the inlet to the evaporator of the heat pump (5 ° C, Fig. 1) and the specified optimum temperature difference between the evaporator and the condenser (35 ° C) are obtained, the temperature of the heating water is 40 ° C at the outlet of the condenser 14, maintaining, at if necessary, in the coldest period of the year, using the peak heater 17, the calculated temperature of low-temperature heating (45 ° C, floor-mounted version for regions with long heating periods). Switching again after accumulation to the heating process, due to the previous minimization of heat loss, by analogy with experiments in similar geological conditions, using in loose soils zones with a weakly manifested groundwater velocity (Nahwarmesystem mit Erdsondenwarmespeicher in Greusenheim. / R. Barthel und and. // Geothermische Fachtagung, Straubing: 12-15 Mai 1998, S.531-538), they return after accumulation for heat supply about 60% of the heat discharged to the service station (in contrast to the practice of accumulation in areas with powerful aquifers, which showed that heat Teri is at least two-thirds of the amount of thermal discharges).

With the end of the heating season, they again proceed to the considered restoration of the soil and coolant temperatures reduced during the heat extraction period by accumulating heat of ventilation exhausts in the soil, then repeating the seasonally changing stages of heat extraction and accumulation in the above sequence.

Thus, without increasing the total number of vertical contours in the well system, but rather, reducing the total depth of well drilling due to shortened contours, it is possible to periodically transfer the coolant from the heat support zone, which is provided by water-bearing layers significant in power and filtration rate, to the higher located zone absent or weak movement of groundwater, solving the problem of seasonal change of hydrogeological conditions and geological zones of coolant supply, from favorable to heat extraction from the ground up favorable for accumulation in the soil thermal discharges. At the same time, there is no danger of faster cooling of the soil during heat removal, due to the shortening of part of the contours, due to the previously increased thermal potential of the soil at their location, due to the accumulation of thermal discharges in these circuits.

An increase in the temperature of the coolant at the inlet to the heat pump by 10 ° C relative to the value obtained in the first heating season without preliminary accumulation of heat discharges (-5 ° C, figure 1), with the same heating mode, corresponds to thermodynamic calculations of an increase of 1.3- 1.4 times the conversion coefficient of the heat pump (KPTN). This confirms the effectiveness of the proposed method in relation to energy saving, which consists in a corresponding reduction, due to the achieved KPTN, power consumption drive TH, which leads to a decrease in annual operating costs.

Even when using the method of the variant of the traditional laying of the well system, with the same distance in the row and between the rows, proceeding from the general principle of eliminating the cooling interference of the SRT during the heat extraction period (h = N in figure 1, where, according to the recommendations, N is chosen at least 6-10 m), with a combination of processes that contribute to the restoration of the thermal regime of the soil (thermal support of groundwater in areas of the aquifers and decrease in the accumulation of part of the accumulators in the heating season with increasing distances nnogo heat through shortened loops location area to the long path), one of the groups SRT operate with significantly shortened wells, which leads to a corresponding reduction in volume of drilling and time-consuming construction works. By the example of the depths of the roof and the bottom of various aquifer layers (usually 30–40, 60–80 m, etc.) that are widespread in a number of central regions of Russia, a decrease in the depth of drilling for shortened service stations, relatively long service stations, can be up to 50 % and more, and the reduction in the cost of drilling work throughout the well system - on average, 25%.

When implementing a variant of the method with close rows of long and shortened service stations (Fig. 1, h is less than H and h ₁ = 3-5 m is specified), used if hydrogeological estimates showed rather low groundwater velocities (0.01-0.025 m per day), additional cost reductions are achieved by reducing the area under the borehole system, as well as materials and work associated with horizontal wiring between service stations, which is especially important in situations where the construction of a multi-well soil heat collection system makes it difficult for the existing lot building.

Another variant of the method, implemented on the basis of an approach using typical SRT versions, is preferably used when the feature of the geological section is a small depth of the roof of the upper aquifer (not more than 20-40 m from the Earth’s surface, for example, in the Yaroslavl region this parameter can vary from the indicated values to 100 m and further). Then, in view of the depth of the possible zone for efficient accumulation of thermal discharges limited by this circumstance, the method is implemented by combining in the well system a combination of designs of vertical circuits of different lengths, in which the shortened circuit design allows to compensate for this factor due to the increased specific heat transfer surface relative to the long circuit (Fig. .3).

For example, as the most corrosion-resistant option for working in the zone of the placement of aquifers, moreover, more economical in unit costs (per 1 linear meter of service station), when mounting a group of long loops 5 as part of the main SCS 8 (Fig. 1) use the widespread, repeatedly tested for reliability in Europe and the world construction design based on vertically installed in the heat-conducting filler wells double U-shaped plastic tubes (for example, from high density polyethylene) with the outside out of the well s input and output branches for coolant supply and selection (3 - twin unit 5 right). As part of the additional WCC 19, a coaxial shortened circuit 6 is used, which is performed with the diameter of the well 4 increased relative to the well 3 (in FIG. 3 - D _{2 is} greater than D ₁ ). Thus, due to the increased circular contact surface with the surrounding soil, which is inherent in the performance of coaxial type SRTs, the contour 6, limited by the features of the geological section, is selected that is selected based on the existing geological section and is designed to accumulate thermal discharges. A shortened circuit 6 is also possible in the form of a segment of a spiral-shaped plastic tube vertically mounted in the well 4 with an outer diameter of the spiral D ₂ .

The considered option is universal in relation to the possibility of applying the method not only in new construction, but also, depending on the specified geological situation, to increase the efficiency of an existing geothermal project, based on equipping it with another circulation system with a service station group of another design, with the existing system with originally mounted service stations.

The proposed method also provides an option that is preferably implemented when hydrogeological estimates show the presence in the regions of regions of plots with virtually no (very slow) groundwater movement in the upper layers of the near-surface soil: these include zones with filtration rates less than 0.01 m per day, figure 1-5 conditionally not shown, located above one or more sufficiently powerful aquifers. In these areas, the method is carried out with seasonal heat removal and accumulation of heat discharges based on a common well, which, when combined with the installation of a long and shortened vertical contours from U-shaped plastic tubes, combines a borehole heat exchanger of the design proposed according to the invention (Fig. 4) .

This allows you to further reduce the size of the site under the well system due to the emerging possibility of a more compact arrangement of wells (in contrast to FIGS. 1-3, with a decrease in the distance in the layout of wells to the same value of h ₁ , also selected in the range of 3-5 m, in FIG. .4 neighboring wells are conventionally shown by axial lines), in particular, in projects implemented under conditions of severe restrictions on the size of sites for construction of service stations.

In this variant of the method, in contrast to the previous versions based on the typical design versions of the SRT (Figs. 1-3), the depth of the wells is chosen to be the same and corresponding to the longer circuit 5, forming, by cladding with heat-conducting filler 4 of the entire cavity of the well 3 (Fig. 4), the same length of the service station in the entire well system. Unlike the STO of a known design, also combining two loops of a loop type in a common well, contours (loops) of different lengths combined with connecting to independently functioning circulating systems are combined here. To do this, using the input and output branches of the U-shaped tubes, the circuit, according to the two selected lengths, is combined into the main and additional closed systems (WCC), the general principle of operation of which is similar to the operation of the WCC 8 and 19 in figure 1.

In the example in figure 4, where in the geological section below is a significant, in terms of power and speed of filtration, the aquifer 2, in accordance with the main variant attribute of the method combining the variants, contours of different lengths are used, each of which, in the considered embodiment, represents a single loop, when this loop of different lengths, with the accumulation of heat vent exhausts or thermal discharges of approximately the same, relatively small potential, are made of tubes of the same diameter (d ₂ = d ₁ ).

A variant of the method with the construction of the SRT proposed according to the invention (Fig. 4) during the heating season, i.e., at the stage of soil heat extraction, is carried out, using, similarly to the previously presented general scheme, the flow of two heat carriers to the heat pump 13 (from long and shortened circuits) along the main 8 and additional 19 WCC, which in this case form hydraulic groups operating independently through well 3 (or a number of wells 3) (Fig. 4). Then, as in the previously considered variants of the method, they switch to the accumulation of heat of exhaust vents in the soil during the inter-heating period, using only an additional CCC during this period, by supplying the coolant through the shortened circuit 6 and then, bypassing the heat pump during this period due to the above jumper switching.

The concentration of seasonally changing processes of heat extraction and accumulation in a common well leads to the possibility of a more compact arrangement of wells (in contrast to FIGS. 1-3, with a decrease in the distance between the wells to the same value of h ₁ , where h _{1 is} preferably chosen in the range of 3-5 m ), due to which they additionally reduce the size of the site under the well system.

The choice of method options and the STO design versions used for their implementation is carried out, guided at the design stage by analyzing the features of the geological sections available at a particular disposal, waste heat sources, possible sites for the construction of borehole soil systems, the purpose and type (new construction or reconstruction) of the project, and also - a set of possible variations technologically feasible at an effective and cost-effective level of consumer services.

For example, based on the above considerations, when implementing projects with the combined installation of circuits of different lengths in a common well, in order to avoid the increased risk of this part of the accumulated heat flux for such an option, due to its possible displacement during the inter-heating period outside the selected well field in the direction of movement groundwater, make more stringent requirements for the selection of possible geological sites for the accumulation of thermal discharges - with filtration rates in the zones e accumulation, i.e. above the aquifer 2 in FIGS. 4-5, approaching 10 ^-9 m / s and below, including options with no moving groundwater.

Other possibilities are envisaged for implementing the variant of the method represented by the fragment in Fig. 4, for example, by attaching the shortened vertical contour 6 to not one, as shown in Fig. 4, a long loop loop, but, for example, to a complex of two U-shaped loops , similar to the one shown on the right in figure 3 (position 5). By combining in one well from 2 to 4 or more contours of two different lengths (the number of U-shaped tubes in a shortened circuit can also be doubled relative to figure 4), limited by a rational increase in the diameter of the well 3, increase the specific heat productivity ( heat removal from 1 linear meter STO) and thus additionally reduce the amount of drilling work. In addition, the expansion of technological capabilities when applying this variant of the method and the design of the SRT proposed for its implementation consists in the possibility of replicating such solutions not only to relatively large objects with a multi-well underground circuit (Fig. 1), but also to objects with low heat demand (for example , cottages) when, taking into account the compact arrangement of circuits of different lengths (Fig. 4), it becomes sufficient to use geothermally as a heat accumulator and a renewable heat source System power supply object of one or two small holes, placed on a small construction site.

The device proposed for implementing the method variant under consideration, which represents the design of the borehole heat exchanger shown in Fig. 4, is launched in a section of a geological section 1 with aquifers (Fig. 4 shows an example with one aquifer 2) into a common well 3 filled with a heat-conducting cement mixture 4, a complex of loops (vertical contours 5 and 6) of different lengths, determined in this example by the levels of the roof and the bottom of layer 2. By analogy with the prot the type that corresponds to the design versions of the workshop in figure 2, when building a workshop based on loops of different lengths, the descent of the loops can be carried out in conjunction with a concrete pipe (not shown conditionally), which after the descent of the complex serves to fill the well 4 from top to bottom with cement mortar , as a result of the hardening of which the STO is formed with the input and output carried out outside the well (according to the directions of the coolant supply indicated by arrows in Fig. 4) by the branches of U-shaped tubes. In this case, the input and output branches of the long and shortened vertical circuits 5 and 6 formed in the well, by analogy with the diagram in Fig. 1, serve to include the circuits in the main closed circulation system of the coolant passing through the heat pump evaporator connected through the condenser to the network heat supply, and the branches of the shortened circuit 6 are connected through a jumper to an additional circulation system connected before entering the evaporator through jumpers with an intermediate heat exchanger 23 for utilization of heat owls. The latter is made with the possibility of connecting to the exhaust line a source of 25 thermal discharges in the form of heat of removed ventilation air, connected via the other side of the heat exchanger 23 to the air distribution unit 32 after the heat exchanger through a jumper 31 to cool the premises of the object.

In the presence of a source of thermal discharges of relatively low potential, such as heat of ventilation discharges, a variant of the method with the proposed construction of the SRT (Fig. 4) is carried out by analogy with the general scheme of operation in Fig. 1 considered earlier with respect to the function of low-temperature heating, accompanied, if necessary, in inter-heating period by the function of cooling the rooms directly from the wells. The advantage will be the possibility of the functioning of circulating systems with vertical contours of different lengths in the space of the general service station, which allows seasonally changing within the space of the same well 3 (Fig. 4) the area of surface soil favorable by hydrogeological characteristics for heat removal during the heating season, to the zone that helps minimize heat loss during accumulation of thermal discharges in the ground during the inter-heating period.

In all the considered variants of the method, by dumping the heat of ventilation blowouts into the service station during the inter-heating period, they perform the functions of thermal recovery and possible, within the limits of the volume of ventilation blowouts implemented in practice in the central regions of Russia, a slight heating (1-3 ° C) of the soil above its initial temperature, preceding the start of the first heating season. For example, by the end of the 10-15 season, due to ventilation emissions, the coolant temperature is maintained before entering the VT evaporator, which is close (5 ° С in Fig. 1) to the initial soil temperature (6-8 ° С for depths up to 100 m, for example, the Yaroslavl region ), providing for the option of using discharges of a relatively small thermal potential, characterized by moderate heating of the soil, expanding the technological capabilities of the method due to the implementation in the inter-heating period of the function of cooling the premises of the facility directly from the wells.

Depending on the source of heat discharges of an increased potential near the heated object, as well as the consumer problems being solved (for example, there is no need to cool the rooms, but it is necessary to use radiators for medium-temperature heating and ensure the DHW mode), the function of soil preheating is enhanced by providing more according to one of the variants of the method of working with thermal discharges from a more powerful source.

According to the first approach discussed above to implement the defining feature of the invention, based on the use of typical SRT designs according to the process variants depicted in Figs. 1-3, a variant with a higher thermal discharge potential is implemented by optimizing the design of the number of shortened circuits of typical designs. Moreover, based, for example, from experiments with the accumulation of heat surplus from KSU in loose soils similar to the central regions of Russia (Nahwarmesystem mit Erdsondenwarmespeicher in Greusenheim. / R. Barthel und. // Geothermische Fachtagung, Straubing: 12-15 Mai 1998. - Straubing, 1998. - S.531-538), which showed the level of return of heat discharges to heat supply - 64%, optimization is carried out on the basis of the indicator calculated according to the results of the experiment: increasing the soil potential due to heat discharges from KGU increases the allowable level of heat removal from 1 pog. m STO at about 100 kWh per year. This will give an almost 100% increase in specific heat removal, calculated earlier according to the option without using heat discharges, using the example of an object in the Yaroslavl region (Heat Supply News, 2007, No. 10, p. 26-33), increasing it by about 2 times.

According to this approach, the general scheme of the implementation of the method will be partially similar to the scheme in Fig. 1, however, additional elements of the scheme will appear, and these differences are presented below together with an example of the second approach to using heat discharges of increased potential, based on the same conditions of absence in the upper geological zone section (above the roof of the upper aquifer) of significant groundwater movement, on the application of the design of the SRT changed relative to figure 4 (figure 5).

This variant of the method provides for the preliminary heating of the soil due to thermal surplus from KGU, relative to the initial soil temperature, up to 25-30 ° C in the geological and climatic conditions of the central regions of Russia (on average 5 ° C lower than in the above experiments for German conditions , where the initial temperature of the soil was higher), which allows for the same given temperature difference in the VT (Fig. 1), even taking into account the temperature drop of the coolant after 10-15 heating seasons by 5-10 ° C, the ability to provide an average temperature -temperature heating regime of the object according to the general scheme shown in Figure 5.

The last SRT option is used in combination with the general scheme shown in FIG. 5, in which, for the convenience of comparison, the positions common to FIG. 1 are saved, if possible (except for position 4). In contrast to the circuit in FIG. 1, the unit 25 for supplying exhaust air to the heat exchanger 23, connected to the unit 32 for air distribution for cooling the premises of the facility, is turned off (conditionally shown in dashed lines in FIG. 5), and instead an additional heat exchanger is introduced into the general circuit 33, for the disposal of thermal surplus with the incoming liquid coolant from the KGU, made of water-water type and connected through the jumper 35 of one of the sides to the block 34 of the source of excess heat (water cooling system of the KGU), and the other side (via jumpers 3 6 and 37, with disconnected 21, 29 and 38) - to the additional ZCC 19 passing through the shortened circuit 6 installed as part of the downhole heat exchanger. Network 15 counts in this case on the possibility of medium-temperature heating and the provision of additional services in the form of hot water ( the general scheme in figure 5, the DHW outlet is conventionally shown by an arrow).

The design of the HUNDRED used in the diagram of FIG. 5, using the thermal potential of excess heat removed from the combined heat and power plant removed during the inter-heating period as an example, has been changed, relative to FIG. 4, to the increased potential of the additional waste heat used, due to the use of a shorter contour 6 from a larger plastic tube diameter than the tube of the long circuit 5 (in Fig. 5, d _{2 is} greater than d ₁ ), with a possible change in the diameter of the borehole 3. Moreover, d _{2 is} selected according to the design parameters that are assigned in accordance with the potential of the additional source stroke or linear flow rate of the coolant through a shortened circuit. Regarding the general scheme (Fig. 5), the SRT is built in this way: the input and output branches of circuit 6, except for connecting through jumpers 21, 20, 10, 28, 11a, 11b with the input and output of evaporator 12 of heat pump 13, are connected through jumpers 22, 37 to an additional intermediate heat exchanger 33, and through it to the block 34 of the utilization of thermal surplus from KGU.

According to a variant of using heat discharges of increased potential, the method is carried out, preferably starting from the stage of accumulation of waste heat in the soil in order to ensure preliminary heating of the soil before the start of the first heating season.

To do this, at the beginning of the inter-heating period, the circulation pump 18 for supplying the coolant is launched with the help of an additional SCS 19 through a shortened borehole circuit 6. With open jumpers 22, 37 and closed 11a, 21, 28, 29, 38, the coolant is supplied to one of the sides of the intermediate heat exchanger 33, while simultaneously connecting to the other side through the open jumper 35 a block 34 for the utilization of excess heat from the KGU, working during this period, mainly to generate electricity, that is, without removing the heat load heating (resulting in the formation of thermal surplus sent to block 34 for disposal). In the heat exchanger 33, part of the heat removed from the KGU is transferred to the less heated liquid coolant coming from the shortened circuit 6, which, as a result of repeated circulations through the heat exchanger 33 and circuit 6, bypassing the heat pump 13, transfers additional heat to the ground, heating it above the initial (natural) state and while heating through the heat-conducting filler 4 of the well 3, circuit 5 with the coolant in it at rest (pump 7 turned off).

At the beginning of the heating season, the accumulation stage is interrupted, using jumpers 22 and 35, turning off the heat exchanger 33 and the heat waste utilization unit 34, and the functioning additional SSC 19 at the same time as the pump 7 is turned on, together with the main SSC 8 through jumpers 9, 10, 11a and 11b , 20, 21, 28 are connected to the input and output of the evaporator 12 when the heat pump 13 is turned on. Next, the liquid coolant, with a temperature increased at the stage of accumulation (as previously indicated, up to 25-30 ° C), during the heating season at the same time repeatedly under was established through the borehole 3 circuit 5 and 6, resulting in mixing at the inlet to the evaporator 12 from two liquids flow ZTSS transmit the heat in the evaporator 12, the working fluid. As a result of multiple circulations through the evaporator and downhole circuits of different lengths during cooling in the evaporator, 3-5 ° C sets the average seasonal temperature of the mixed flow at the inlet of the evaporator in the range of 20-25 ° C (Fig. 5, taking into account the above geological corrections climatic conditions of the Yaroslavl region).

According to the previously discussed thermal transformation processes in the heat pump, based on the temperature of the flow at the inlet to the evaporator and the set effective temperature difference between the evaporator 12 and the condenser 14 (35 ° C), identical with the circuit in Fig. 1, the heating temperature is obtained at the outlet of the latter water 55-60 ° C, which, if necessary, in the coldest period of the year is increased with the help of a pre-heater 17 to a design maximum of 65-70 ° C, corresponding to the medium-temperature heating mode, carried out in the network 15 using a radiator in (Fig. 5 heating appliances are not conventionally shown). In addition to medium-temperature heating, due to the temperature of the water after the condenser maintained with the help of a storage tank (not shown), in contrast to the circuit in Fig. 1, in the heating period, the calculated DHW parameters (55-60 ° C) are also provided through the heat pump, expanding into As a result, the technological capabilities of the scheme according to the variant “medium temperature heating + DHW” (in Fig. 5, the tap behind the condenser 14 on the DHW is indicated conditionally by an arrow). With the end of the heating season, the operation of the main ZSC 8 is stopped, turning off the circulation pump 7 and interrupting the flow of coolant through both ZTSS (8 and 19) through the evaporator 12 by blocking the jumpers 9, 10, 20 and 28. At the same time, blocking the jumpers 21 and 11a, the heat carrier is bypassed by the heat pump, that is, by means of the pump 18 according to the additional ZCC 19, through the intermediate heat exchanger 33 reconnected with the help of jumpers 22, 36, 37 (jumpers 29, 38 are closed), connecting it to the excess heat block 34 during this period from KSU, and - further, through about covered bridge 11b, with a short circuit 6.

Thus, as a result of repeated circulations through the heat exchanger 33, the coolant entering the inter-heating period through one of its sides has a temperature significantly lower during the heating season (due to heat removal in the evaporator) relative to the average seasonal values at its inlet (Fig. 5), gradually cooling the soil during the supply cycles through the service station during the season, is heated by the surplus from KGU supplied through the other side of the heat exchanger 33. This leads, with further repeated passing of the heated coolant through the shortened circuit 6, to restore during the inter-heating period the temperature of the soil in the vicinity of circuits 5 and 6, in a zone extending from the Earth's surface to the level of the roof of the aquifer 2 (Fig. 5). As a result, by the beginning of the second and subsequent heating seasons, the soil temperature is returned to the value acquired as a result of preliminary accumulation of waste heat before the start of the first season (in this example, about 25-30 ° C).

In the future, the provision of such temperatures at the beginning of each heating season is also facilitated by the fact that due to a decrease, according to the invention, at the stage of accumulating the coolant supply depth, the thermal effect of groundwater moving below the final elbow of the shortened U-shaped contour (Fig. 5) and having in this case, a lower temperature than the upstream heated soil does not extend to this zone, which minimizes the losses of heat accumulated during the inter-heating period.

Since at the stage of accumulation, changes in the level of heat discharges from KGU during the inter-heating period are possible, the flow rate of the coolant through a shortened borehole circuit 6 is regulated according to the varying proportion of waste heat by adjusting the drive of the circulation pump 18 as part of an additional cooling pump 19 (Fig. 5), including the possible distribution of heat surplus from the total KGU to several energy consumption facilities, each of which is equipped with downhole systems.

Carrying out the method in the above sequence, in the following heating seasons, they provide approximately the same average seasonal temperature of the coolant (20-25 ° C, Fig. 5) in the flow from circuits 5 and 6 of different lengths mixed before entering the heat pump evaporator. At the same time, some cooling of the coolant, due to the passage of one of the streams of the zone of moving groundwater (through a long circuit 5, the lower part of which interacts with the aquifer 2) at the stage of heat extraction from the soil, is almost completely compensated by the further removal of the coolant to the exit from the service station through more heated upstream zone, as well as mixing of flows coming from circuits of different lengths at the inlet to the heat pump evaporator.

At the same time, depending on the specific energy-supplying facility, it is possible to use the heat exchanger 33 both by selective (Fig. 5, dashed lines indicate that the ventilation unit 25 is turned off) and additional connection - according to the variant of the integrated use of ventilation heat (using the STO design figure 4) and thermal surplus from KSU (using STO another design - figure 5). The latter option is implemented, for example, in projects for joint implementation of underfloor heating / cooling of the first floor of a residential building and heating with radiators / hot water supply of the second floor.

When using this variant of the method with the installation of shortened and long circuits using wells of different lengths (Figs. 1-3), long circuits, during the heating of the soil (from KGU), are partially cooled due to the flow of the lower parts with ground water, if the described system is modified , with the creation of an additional line - for separate use of the main ZCC, as a result of connecting it through additional jumpers (not shown in the general diagram of FIG. 5) to the heat exchanger 23 and the ventilation unit 25, they can be used for cooling Rental of rooms on the second floor.

A significant increase in the thermal potential of the soil before the first and subsequent heating seasons due to waste heat of increased potential, maintained during the inter-heating period due to minimal heat loss in the upper zone of the geological section, subject to flexible temperature control and additional insulation of the horizontal wiring of pipes in the upper layer of the Earth, is used for use of ordinary water as the heat carrier circulating through borehole heat exchangers. This leads to an increase in the heat capacity of the coolant and a decrease in its cost relative to materials with antifreeze additives, which is an additional advantage of this method variant.

Subject to the selection of an appropriate geological site, which is practically not subjected to heat dissipation in the upper zone by groundwater with filtration rates below 0.01 m / day (below 1-3 m / year), and characterized by significant aquifers in the lower zone, seasonal cultivation is favorable the zones of implementation of the stages of heat extraction and accumulation combined in a common well, due to the proposed structures of the SRT, can further increase the specific heat removal (per 1 linear meter of SRT), the coolant temperature the output of the service station and the inlet to the evaporator of the heat pump (VT), and, consequently, the conversion coefficient (KPTN).

So, on the example of a complete set of the proposed construction of the HUNDRED (Fig. 5), standard-grade high-density polyethylene pipes with diameters of 32 and 40 mm (for long and shortened contours, respectively) with an increase in the diameter of the well, relative to the common one-loop design, from 150 to 180 mm, in the conditions of the heating season in the Yaroslavl region (about 5300 hours per year), the calculated heating parameters of a residential building with the accumulation of heat discharges from KSU will be: in the medium temperature mode (heating in the condenser ТН to 60 ° С, 5) - the average seasonal KPTN (for 15 seasons) about 4 units; in low temperature mode (up to 40 ° C, in contrast to figure 1 - from 20 ° C at the inlet to the evaporator VT) - about 5 units Even when using discharges of lower potential, in the form of heat of ventilation exhausts, using the design of the SRT in Fig. 4 (tube diameter 32 mm), the calculated indicator for the low-temperature heating option will be at least 4.0 units. These indicators will ensure an effective level of reduction in operating costs for central and other regions of Russia, with optimized energy consumption by a ground heat pump drive. Relative to the KPTN achieved so far in the first domestic plants operating in the heating mode (2.5 units), the reduction in consumption is 40-50%, and relative to world analogues with the accumulation of thermal discharges in close conditions (KPTN = 3.3-3.5 units .) - approximately 20-25%.

An increase in the specific heat removal in combination with a decrease in the number of wells during the joint installation of circuits of different lengths in them leads to an even greater reduction in the cost of constructing a well system in the framework of the proposed method, as well as overall investment in geothermal projects associated with the use of low-grade heat from surface soil.

Thus, the proposed method extends the technological capabilities of the considered analogues and prototype due to the effective implementation of the heating function in various temperature conditions, along with other consumer functions (hot water supply, cooling), for regions with different geological and climatic conditions, including - with long heating periods (up to 5000 h / year or more) and low soil temperatures to a depth of 100-200 m (5-10 ° C).

The main (unifying) advantage of all the proposed variants of the method is the fact that, as a result of the possibility of a seasonal change in the depth of supply of the coolant, due to the design of the soil heat collection system in the form of cascades of wells or vertical borehole loops of different lengths, the method allows periodically, at the end of the heating season, move the coolant from the effective heat removal zone, characterized by a significant thermal contribution of the groundwater velocity in the aquifers a, in the zone of effective accumulation - above the top of the upper aquifer, characterized, due to the lack of a developed flow of water, by minimal losses of accumulated heat during the inter-heating period.

The technological schemes and variants of the method discussed above, together with the results of experiments conducted in geological conditions close to the central regions of Russia, also indicate the possibility of increasing the annual heat removal in these regions from 1 linear meter. m STO - from 90-100 to about 150 kWh per year, according to an option that includes the use of heat from ventilation exhausts and geothermal heat, taking into account the heat support of the aquifers located in the lower zone of the STO (Heat Supply News Magazines - No. 10, 2007, p. .26-33 and No. 5, 2010, p. 25-32). According to the variant with thermal surplus from KGU, this value can increase to 250 kWh / pog. m per year and further, which is 2.5 times more compared to a technology that uses only geothermal heat (excluding groundwater and thermal discharges). According to rough estimates, this is also no less than 1.5 times greater than when using the closest analogues of the proposed method under similar conditions, since they are not technologically and structurally designed for the maximum efficiency of each of the stages carried out seasonally in downhole systems (selection and accumulation heat). In the method, this disadvantage is eliminated due to the optimal use of varying depth characteristics of the geological section.

These indicators, directly related to the decrease in the total length of wells and the number of service stations during the design of soil systems, contribute, as a result, to a decrease in the areas occupied by the systems and the volume of construction and installation works, including - to perform horizontal pipe wiring between service stations, lead to lower initial costs for the construction of the well system (in relation to the applied variants of the method, the highest indicator is for the option with the installation of U-shaped contours of different lengths in a common well) and - total investment in heat pump soil installations by an average of 25%.

These advantages make it possible to eliminate the economic inconsistency of the implementation of previous technologies, in relation, for example, to the implementation of effective heating indicators in Russian regions with long heating seasons. This will contribute to a fairly wide circulation of the proposed method to regions with different geological and climatic conditions, including - due to its multivariate applications related to the features of the territory, types of energy supply and applied structures of service stations.

Claims (7)

1. A method for seasonal use of low-grade heat of near-surface soil, in which low-grade heat is taken from the soil during the heating season by supplying liquid coolant through the soil layers using the main closed circulation system with closed vertical circuits installed in it by using wells, and the subsequent heat transfer, with its conversion by using the heat pump cycle to a higher temperature level, to the heat supply with These are the objects of energy supply, and during the inter-heating period they switch to the accumulation of external thermal discharges in the soil, transferring the coolant supply through the soil layers to an additional closed circulation system with an intermediate heat exchanger disposing of the heat discharges installed in it, characterized in that during the transition from heat removal to accumulation of thermal discharges change the depth of the coolant supply through the soil layers from the level of intersection by vertical contours of one or more aquifers Unta to a level above the roof of the upper aquifer, for which some of the circuits used to take heat from the soil are used when taking heat and accumulating heat discharges according to a shortened version, by installing these circuits as part of an additional circulation system with a length corresponding to the second of these levels while the remaining circuits are set as part of the main circulation system with a length corresponding to the first level. 2. The method according to claim 1, characterized in that when the heat of the soil is removed during the heating season, the coolant is supplied simultaneously through the main and additional circulation systems using downhole heat exchangers based on combinations of long and shortened vertical circuits with wells of corresponding different depths, and when accumulating thermal discharges in the soil during the inter-heating season, the coolant is supplied only through an additional circulation system using borehole heat exchangers of the same length based on a combination of shortened circuits with wells of the corresponding depth, while long heat exchangers of the same length formed by another combination in the main circulation system are placed in a row perpendicular to the movement of groundwater in aquifers, at least 6-10 m apart , and in pairs with shortened heat exchangers placed in a row in the composition of the additional circulation system, shifting relative to the latter in the direction of groundwater movement by a distance selected by the speed of water movement above the aquifers, in the range of 3-5 m. 3. The method according to claim 1, characterized in that when using vertical circuits in the form of U-shaped plastic tubes for the selection of heat and accumulating thermal discharges in the form of U-shaped plastic tubes, circuits of different lengths used as part of the main and additional circulation systems are placed in pairs inside each well, the depth of which is selected according to the long circuit, while the heat is removed using the main and additional circulation systems and the accumulation of heat discharges is carried out using wells of the same depth, forming with placed in them a pair of circuits of different lengths and a heat-conducting filler of the well borehole heat exchangers of the same length. 4. The method according to claim 2, characterized in that when the depth of the roof of the upper aquifer does not exceed 20-40 m, shortened downhole heat exchangers are used with an increased specific heat transfer surface relative to long downhole heat exchangers, by using different design heat exchangers for selection and storage versions, installing, for example, in the main circulation system heat exchangers with vertical circuits in the form of U-shaped plastic tubes, and in an additional circulation system The system is heat exchangers in the form of a vertical coaxial type circuit made using a well of increased diameter relative to long heat exchangers. 5. The method according to any one of claims 1 to 4, characterized in that when accumulating heat discharges in the soil, the shortened circuits are used with the possibility of connecting an additional circulation system, through the main or additional intermediate heat exchanger disposing heat exchanger, to it, an additional source of discharges including with increased potential relative to the main source, for example, heat surpluses allocated during electricity generation during the inter-heating period of the cogeneration plant by setting the flow rate or flow rate of the coolant through the shortened circuits in accordance with the selected share of the potential consumption of the additional source through the intermediate heat exchanger, either by optimizing the design of the number of shortened circuits of typical designs, or by applying a modified, according to the variant pairwise placement of long and shortened circuits in the well , the execution of the downhole heat exchanger, while the flow through the additional circulation system is regulated in accordance with POSSIBILITY change this share for interheating period. 6. A downhole heat exchanger for seasonal use of low-grade heat of near-surface soil, comprising a well with at least two vertical circuits for supplying liquid heat carrier installed in the heat-conducting filler of the well, made in the form of loops of U-shaped plastic tubes, the input and output branches of which are included into a closed coolant supply system equipped with a circulation pump through a heat pump evaporator connected by its condenser to the heat supply network an energy supply facility, while the outlet branches of the tubes before entering the evaporator are connected through jumpers and an intermediate heat exchanger for the utilization of heat discharges to an external source of discharges, characterized in that the loop loops formed by the tubes are made with different lengths, while the length of the long loop loop and the corresponding well depth selected taking into account the intersection of the contour and the well, at least one aquifer located in the soil, and the length of the loop shortened con Hurray is chosen with the possibility of placing the circuit above the roof level of the upper aquifer, while the input and output branches of the long circuit tube are included in the main closed coolant supply system, the branches of the shortened tube are connected to an additional closed coolant supply system equipped with another circulation pump, connected through a jumper to the outlet of the shortened circuit with the inlet of the heat pump evaporator and the water side of the intermediate heat exchanger, selected water-air version with the possibility of joint or separate use of the main and additional closed systems through jumpers in the heating season for the extraction of soil heat and transfer of coolant flows through both systems to the heat pump evaporator, and the shortened circuit is made with the possibility of connecting through the jumper the supply of soil cooled as a result of heat extraction liquid heat carrier in the inter-heating period to the exhaust line of the source of thermal discharges in the form of heat of removed ventilation air from the energy exchange object baking connected via another side of the intermediate heat exchanger with the exhaust air supply line after the heat exchanger for cooling the object space. 7. The downhole heat exchanger according to claim 6, characterized in that the shortened vertical circuit is configured to be connected via a jumper to an additional source of thermal discharges, including with an increased thermal potential relative to the main source, for example, in the form of heat surplus serving a given or other energy supply facilities of a cogeneration unit, and an additional closed heat transfer system is provided with an additional intermediate heat exchanger utilization of heat discharges of the selected water-water version installed in the system with connection of one of its sides to the input and output branches of a shortened loop through the jumpers, the other side to an additional source of thermal discharges, while the number of shortened vertical contours in the well, the ratio of diameters tubes of long and shortened contours and the well diameter corresponding to these parameters are selected taking into account the given ones, in accordance with the possible share consumed the potential of an additional source through an additional intermediate heat exchanger, flow parameters or linear flow rate of the coolant through a shortened circuit.

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