ITBA20130032A1

ITBA20130032A1 - GEOTHERMAL PROBE WITH CIRCULAR PLATES

Info

Publication number: ITBA20130032A1
Application number: IT000032A
Authority: IT
Inventors: Nicola Pastore
Original assignee: Nicola Pastore
Priority date: 2013-04-29
Filing date: 2013-04-29
Publication date: 2014-10-30

Description

DESCRIZIONE DESCRIPTION

Dell'invenzione industriale dal SONDA GEOTERMICA A PIASTRE CIRCOLARI Of the industrial invention of the CIRCULAR PLATE GEOTHERMAL PROBE

Campo Tecnologico Technological field

La presente invenzione è relativa ad una sonda geotermica a piastre circolari utilizzabile nel contesto dello sfruttamento della falde acquifere come risorsa geotermica a bassa entalpia. The present invention relates to a circular plate geothermal probe that can be used in the context of the exploitation of the aquifers as a low enthalpy geothermal resource.

Stato dell'arte State of the art

Nel campo dello sfruttamento delle energie rinnovabili la geotermia a bassa entalpia rappresenta una valida opportunità applicabile in numerosi contesti ambientali. Si parla di energia idrotermica allorquando vi è la presenza di acqua di falda che aumenta notevolmente il calore specifico delle formazioni geologiche che aumentare, in funzione della circolazione idrica, la quantità di calore estraibile o cedibile. Anche in assenza di gradienti geotermici anomali, le temperature del sottosuolo rientrano nell'ordine dei 10 - 18 °C. pertanto è possibile sfruttare le risorse energetiche del sottosuolo anche in zone non interessate da particolari condizioni geotermiche. A tal riguardo si osserva che le risorse idriche sotterranee risultano particolarmente adatte allo scopo. In the field of the exploitation of renewable energies, low enthalpy geothermal energy represents a valid opportunity applicable in numerous environmental contexts. We talk about hydrothermal energy when there is the presence of groundwater which significantly increases the specific heat of the geological formations which increase, depending on the water circulation, the quantity of extractable or transferable heat. Even in the absence of anomalous geothermal gradients, the subsoil temperatures are in the order of 10 - 18 ° C. therefore it is possible to exploit the energy resources of the subsoil even in areas not affected by particular geothermal conditions. In this regard, it is noted that groundwater resources are particularly suitable for the purpose.

Gli impianti idrotermici allo sfruttamento dell'energia rinnovabile sotto forma di acqua a bassa entalpia contenuta negli acquiferi possono comprendere due configurazioni : a (closed- loop ) e circuito aperto (open - loop). Hydrothermal plants for the exploitation of renewable energy in the form of low enthalpy water contained in aquifers can include two configurations: a (closed-loop) and open-loop (open - loop).

Negli impianti closed - loop lo scambio di calore tra la superficie ed il sottosuolo avviene per mezzo di sonde geotermiche. La più comune tipologia di installazione prevede di tubi in polietilene collegati con un raccordo a "U" alla loro estremità inferiore dopo aver realizzato una perforazione verticale eseguita nel suolo. Oltre alle classiche configurazioni geometriche ad "U" esistono le sonde a geometria elicoidale, a geometria coassiale, e forme più complesse che mirano ad incrementare energetica (particolari geometrie sono mostrate nel brevetto US 7.370.488 ). All'interno della sonda viene fatto un fluido operativo che rappresenta il mezzo con cui lo scambio di calore. Il fluido è quindi poi convogliato ad una pompa di calore che ne innalza o abbassa la temperatura per poterlo infine trasferire ai terminali di riscaldamento o raffrescamento. Negli impianti open - loop, l'acqua di falda, che in questo caso è anche il fluido operativo, è prelevata direttamente dall'ambiente per mezzo di pompe di prelievo ed ivi reimmesso una volta avvenuto lo scambio termico. L'acqua emunta va direttamente nella pompa di calore oppure si utilizza uno scambiatore di calore interposto tra il circuito acqua di falda e il circuito del fluido operativo che circola nella pompa di calore. In closed - loop systems, the heat exchange between the surface and the subsoil takes place by means of geothermal probes. The most common type of installation involves polyethylene pipes connected with a "U" fitting at their lower end after making a vertical perforation made in the ground. In addition to the classic "U" geometric configurations, there are probes with helical geometry, coaxial geometry, and more complex shapes that aim to increase energy (particular geometries are shown in US patent 7,370,488). Inside the probe is made an operating fluid which represents the means by which the heat exchange. The fluid is then conveyed to a heat pump which raises or lowers its temperature in order to finally be able to transfer it to the heating or cooling terminals. In open - loop systems, the groundwater, which in this case is also the operating fluid, is taken directly from the environment by means of sampling pumps and reintroduced there once the heat exchange has taken place. The water discharged goes directly into the heat pump or a heat exchanger is used between the ground water circuit and the operating fluid circuit that circulates in the heat pump.

Nel contesto dei sistemi idrotermici che sfruttano le acque sotterranee gli impianti open — loop presentano una resa termica più alta rispetto agli impianti closed - loop trasportano calore per convezione forzata. Per contro essi richiedono una falda acquifera in grado di fornire una portata adeguata e devono sostenere i costi energetici non trascurabili connessi al pompaggio delle acque sotterranee fino a superare la quota del piano campagna Inoltre occorre superare le problematiche connesse allo smaltimento legale delle acque. Gli impianti a circuito chiuso, pur avendo una resa termica minore, risolvono le problematiche dello smaltimento delle acque e hanno dei costi energetici ridotti, Comunque quest'ultimi possono perdere in il beneficio arrecato dalla presenza di falda in funzione del contesto idrogeologico. In acquiferi fratturati o in acquiferi stratificati in cui vi è di zone ad alta permeabilità idraulica (fratture negli acquiferi fratturati o depositi ghiaiosi - sabbiosi negli acquiferi stratificati) e zone a bassa permeabilità idraulica (roccia compatta negli acquiferi fratturali o depositi limosi — In the context of hydrothermal systems that exploit groundwater, open - loop systems have a higher thermal output than closed - loop systems transport heat by forced convection. On the other hand, they require an aquifer capable of providing an adequate flow rate and must bear the non-negligible energy costs associated with pumping groundwater up to exceeding the level of the ground level. Furthermore, the problems associated with the legal disposal of water must be overcome. Closed-circuit systems, despite having a lower thermal yield, solve the problems of water disposal and have reduced energy costs, however the latter can lose the benefit caused by the presence of groundwater depending on the hydrogeological context. In fractured aquifers or in stratified aquifers in which there are areas with high hydraulic permeability (fractures in fractured aquifers or gravelly - sandy deposits in stratified aquifers) and areas with low hydraulic permeability (compact rock in fractural aquifers or silty deposits -

Claims

CLAIMS 1) Closed circuit geothermal probe (1) comprising at least one coaxial extension pipe (2), at least one heat exchange system (5) and at least one pumping device for the withdrawal of groundwater (3a).

2) Geothermal probe as per claim 1), characterized in that the aforementioned heat exchange system (5) comprises at least two circular plate exchangers (4a. 4b) and at least one device for the forced circulation of groundwater (3b) in the aforementioned circular plate heat exchangers.

3) Geothermal probe (1) as per claim 1) where more of the aforementioned heat exchange systems (5) can be installed in series in the same geothermal probe (1).

4) Geothermal probe (1) in accordance with the previous claims, characterized in that the aforementioned circular plate heat exchanger (4a, 4b) consists of a package of circular heat exchange plates (6a, 6b, 6c) and at least one circular filter plate (25a, 25b) for withdrawing and introducing groundwater at different depths.

5) Geothermal probe (1) in accordance with the previous claims, characterized by the fact that the aforementioned circular filter plate (25a, 25b) can be positioned both at the lower and upper ends (25a) and inside the aforementioned heat exchanger with circular plates (25b).

6) Circular heat exchange plate (óa, 6b, 6c) in accordance with the preceding claims, where the sealing and alternation of the passage of the flow of the operating fluid and of the flow of groundwater is obtained by means of the gasket (10a , 10b).

7) Geothermal probe (1) in accordance with the previous claims, characterized in that the aforementioned pumping / circulation device (3a, 3b) consists of at least one submersible electric pump (2 la, 21 b), at least one coaxial tubular element (22), at least two circular plates for deviating the operating fluid (20a, 20b, 29) placed at the lower and upper ends of the aforementioned coaxial tubular element, at least one packer (24) placed on the external surface of the aforesaid coaxial tubular element for separation hydraulics of the withdrawal area from the input area.

8) Coaxial tubular element (22) as per one or more preceding claims, where between the sectors of the external circular crown, in which there is the passage of the operating fluid, there is a cavity filled with insulating material (23) for separation between the flow and return circuits.

9) Geothermal probe (1) as per one or more preceding claims, characterized in that the aforementioned coaxial extension pipe (2) consists of three concentric pipes (16, 17, 18), at least one access for the delivery (14 ) and the return (15) of the operating fluid, at least one access for the withdrawal of groundwater (13), at least one deviation plate (19) located at the lower end.

10) The geothermal probe (1) of one or more preceding claims, where the operating fluid circuit is closed by means of the closing plate (30).