US20120167870A1

US20120167870A1 - System for storage and transfer of heat energy

Info

Publication number: US20120167870A1
Application number: US13/377,645
Authority: US
Inventors: Vito Lavanga; Antonio Cesare Sparacino; Robertto Quadrini
Original assignee: ESAE Srl
Current assignee: ESAE Srl
Priority date: 2009-06-12
Filing date: 2010-06-11
Publication date: 2012-07-05
Also published as: WO2010143161A3; WO2010143161A2

Abstract

The present invention relates to a system of transfer and storage of thermal energy to and from the surrounding environment. In particular, this invention relates to a thermo-well (1) comprising at least a case (2) underground, at least one inlet pipe (10) of a heat carrier fluid and at least one outlet line (9) of said heat carrier fluid, wherein said case (2) is sealed, characterized in that said at least one case (2) contains within it an inert material (G) in granular form with which that heat carrier fluid is placed in contact to get an heat transfer between said heat carrier fluid and said inert material (G). Further objects of the invention are an heat transfer system and a storage of thermal or freezing energy and a cogeneration energy system comprising at least one thermo-well as defined above.

Description

The present invention relates to a system of transfer and storage of thermal energy to and from the surrounding environment.

STATE OF ART

The generation of electricity from renewable sources has become in recent years an increasingly recognized need worldwide. The risk that, in a not too distant future, oil extraction can stop or slow down due to depletion of oilfield or due to political or economic reasons, gave an impetus to the research for new energy sources. Ecological reasons have concentrated efforts on developing low environmental impact systems, especially on developing systems that do not involve the emission of pollutants into the air or water. Among these systems are included, for example, solar power generators, the exploitation of geothermal energy and Aeolian generator.
Although the use of fossil fuels is the main energy source and it is in some ways difficult to replace, it goes without saying that a device that can reduce wasted energy, minimizing the energy supply from non-renewable sources, has a remarkable value both economic and environmental.
The aim of the present invention is therefore to make available a system to reduce this wasted energy, capturing the heat energy available from the surrounding environment and that is otherwise destined to be lost.
This aim is achieved by a system capable to capture and store thermal energy as outlined in the attached claims, whose definitions are an integral part of this description.

SUMMARY OF THE INVENTION

The present invention relates to a system as defined above, which includes a so-called' “thermo-well.” According to the invention, the thermo-well is a container of crushed inerts in a reasonable size, variable in volume and geometry, pursuing, through predefined ratio surfaces/volumes, functions of energy storage and/or transfer. These inert materials may be, for example gravel or stones submerged in water, typically local and low cost materials that, due to their physical and chemical characteristics, give to the ensemble a heat capacity substantially equal to that of water, having about half specific heat with respect to water, but with about double density. Another important feature of these materials is to have a superior thermal conductivity, which is preferably about double or even a higher value than thermal conductivity of water.
By way of example but not limitation, the thermo-well with a concrete case, for example made of a set of rings of vibrating concrete, waterproofed and sealed airtight at the bottom and lid. The case contains within it a mass of inert material of different sizes (eg 20-30 mm), with high heat capacity (which makes this material preferable to water for more benefits of static and thermal excursions) and good thermal conductivity (to maximize heat conduction to the outside through heat bridges made from the case and cement inerts it contains, which extends the property of thermal inertia to the surrounding inert mass).
Heat is transferred through the percolation of water (or other heat carrier fluid) in the inert mass, collecting and releasing the heat carrier fluid preferably in diametrically opposite points or by creating a tortuous path of the heat carrier fluid through the inert mass, and preferably providing receptacles homogenization (thanks to the installation, at the bottom or at the top, of larger inert or spacing elements such as the igloo for loose stone foundation).
It is important that both inlet and outlet pipes are submerged below water level in the thermo-well, to maintain the closed-circuit and therefore reduce or even eliminate the power required for the recirculation pump. In this way the circulation in communicating vessels is obtained, without prevalence, using the usual techniques for the hydraulic pumps circulators.
The artefact, due to the properties of the inerts contained and of the concrete container, offers a wide temperature range, being able to operate smoothly between −50° C. and 250° C., with extremes of temperature limited mainly by the possibility of lowering the limit of freezing point or raise the boiling point of the heat carrier fluid through the use of suitable diathermic substances. This temperature range can be further expanded through proper technical measures and substances known to the expert. Extreme temperatures can be reached in the thermo-well of the invention with a suitable insulation of the outer shell of the thermo-well. This possibility makes the present invention particularly attractive in many industrial processes both in the cold-cycle and in the heat-cycle.
In residential uses, the aim is to compensate the temperature deviations from the environment, and extreme solutions of insulation are not justified, insulations that are strategic in industrial compartment.
The artefact points out a heat capacity of about 1.14 kWh/(m³.K). Therefore, considering a delta of 5° C., the system of the invention provides a theoretic power of about 5.7 kW/m³.
It should be noted that up to now energy storage has been mainly carried out by using water as an element of storage, which has seldom been used over its boiling point. There is no evidence of artefacts who use products of wide consumption such as stones and rocks from rivers or quarries, in both residential and agro-industrial processes, where normally suitable and capacious tanks are used filled with water or other fluid mixtures, useful also for the purpose of storage. There is no evidence of artefacts intended for thermal storage, both in residential and in large agro-industrial production as described below.
In one embodiment of the present invention, the said thermo-well is used in an energy cogeneration system.
The distributed cogeneration is now mainly carried out using solutions that implies thermoelectric cogeneration in areas with a high concentration of users of electrical and thermal energy. There are solutions that use smaller machines for co-generation, severely limited in their effectiveness of use in terms of persistent loads and potential mortgage, in various service sectors, hotels, residential and industrial processes. For all solutions, standardizing and introducing the index SCOP (Coefficient Of Performance System, a dimensionless index which compares the energy supplied to the energy produced), it appears as follows: put 100 the chemical potential of the primary source (superior calorific value, expressed either in J, kWh or kCal) of fuel used (fossil, plant biomasses or manure), it becomes available about 90 in canonical cogeneration power plants (including thermal and electrical), with higher performance in technologies that use absorption (ammonia or lithium bromide) where it tends to about 150 (recovering part of the delta over previous solutions from renewable sources). A significant rise in performance compared to both types of solutions mentioned above is pointed out by the idea here developed, leading the SCOP index over 400, in constant persistence of simultaneous users of warm and cold. The large delta compared to the current systems is achieved by managing the energy and by planning of the system to immediate use by means of mere circulation. Thus, the present invention, unlike all the current existing solutions, offers a significant answer to the need to overcome the lag time between production and use, both of warm and of cold, taking advantage of excess power production in downtime and low absorption by the major utilities.
This embodiment, therefore, involves the coupling of a heat pump to a generator, where the heat pump absorbs excess energy (in case of surplus, according to the technical note, you should change the system and reduce production, selling out or dispersing energy to the local distributor which, in non-peak times, tends to reject) and converts it into thermal energy (heat and cold cycle), for its use deferred in time. This maximizes the time lag between production and use.
The system consists of a modular plant designed according to two different solutions: 1) by use of standard electric generators, 2) by use of standard co-generation machines. Both solutions take advantage of the electric potential, serving a one-way cooling unit (machine easier and more solid than the reversible heat pumps), coupled to appropriate water management subsystems associated with basic exchangers of refrigeration unit, making unnecessary the reverse of cryogenic gas, which is also impractical in high power systems. The aim is to exploit the power supply available, in the absence of priority energetic loads, providing storage of thermal energy (warm and cold) in appropriate thermo-wells.
According to this embodiment, the system comprises a generator (eg, with average performance of 40% and peaks of excellence up to 60%), a heat pump (water-water refrigeration unit (with the COP, ie “Coefficient Of Performance”, about 5, EER, namely “Energy Efficiency Ratio” of 4, with peaks of excellence of about 7 and 6, respectively, still significantly improvable in the presence of proper thermal differential and through the use of inverter technology) a warm thermo-well (with insulated core, sited and designed to store, in geometry with a low surface/volume ratio, surrounded by a space sized and designed to transfer in geometry with an high surface/volume ratio), a cold thermo-well (with insulated core, sized and designed to store, in geometry at low surface/volume ratio, surrounded by a space sized and designed to transfer in geometry with a high surface/volume ratio). The technical chambers, both of the generator and of the cooling unit, are insulated and maintained at appropriate thermal regimes, recovering and preserving the surplus heat in the appropriate areas of the thermo-wells, till to pulling down the fumes at the environmental level.
The energetic potential available, considering the standard values of exercise in comparison with optimal users (distribution with terminals with high exchange capacity, such as fan-coil, radiant floor panels, specific activity processes) are represented as follows (potential recoveries from renewable sources such as solar thermal, Aeolic and geothermal micro surface are not calculated) with a numerical example (all steps are expressed in kWh):
Providing 100 kWh to the generator, 40 kWh are obtained in electricity and 60 kWh in thermal energy. The 40 kWh of electricity are supplied to the refrigeration unit, which removes 160 kWh (40 kWh×4) from the cold thermo-well and pours 200 kWh (40 kWh×5, of which 160 kWh removed from the cold thermo-well and 40 kWh of electricity supplied to the refrigeration unit) in the nucleus of warm thermo-well. Overall there will be therefore 420 kWh (60+200+160) available to the end users (including warm and cold) by mere circulation of fluids warm or cold. This index is significantly improvable if the system is implemented with contributions from renewable sources (thermo-surface, thermo-coat, thermo-Aeolic), such as it will be shown in the further embodiment described below.
The cogeneration system object of this invention allows the generator to work with more constant regimen, satisfying first the electrical loads and then the thermal loads. The result is an higher perfomance, a more consistent regimen of the generator, more hours per year of work and a better overall mortgage.
According to a further embodiment, the co-generating system of the invention may have a renewable source of heat such as that resulting from a “thermo-coat.”
The thermo-coat in accordance with the present invention gets under way cheap and widely available products. One or more layers of appropriate thickness of an embossed sheath are applied on the exterior walls of a building (block or industrial), where at least the first layer has the ashlars facing the wall to be protected. Ventilation racks which connect the air gap between wall and sheath with the outside air and whose function is to standardize the pressure inside with the atmospheric pressure are arranged. Then, using a large number of anchorage, a sheet with corrugated profile is applied, such as a corrugated aluminium panel, with the back of the fret facing the sheath and the fret arranged horizontally in order to create horizontal channels preventing vertical motion (updrafts) of the air contained in them. In the belly of the fret a pipe is set down containing a heat carrier fluid, ideally a serpentine coil that runs through all or part of the wall covered by the thermo-coat. A wire mesh panel thermo-welded and shaped according to the thickness required is then applied, with an adequate number of anchor points and having a grasping function for the subsequent plasters based on inerts (mainly of sand and cement with high thermal conductivity) for a layer of several inches, possibly with more covers. It is then possible to proceed with the desired finish, using colours and coatings with suitable thermal properties. The possible application of honeycombed translucent media enhance the capturing function, on proper surface portions matching the need to satisfy (sanitary warm water in summer). The appropriate design and finishing of the outer layer will provide acoustic insulation.
The tubes containing the heat carrier fluid, heated by the sun incident on the surface of thermo-coat, could be put into communication with the warm thermo-well of the cogeneration system described above, or by direct leaching of the fluid in the thermo-well or by catching, by appropriate equipment of heat transfer, the circuit of the heat pump.
In a different embodiment, the thermo-coat can be used independently from the cogeneration system. Where the thermo-coat is built with the pipeline with heat carrier fluid, the heat stored by the circuit of thermo-coat can be used directly for all the users' wish, for example to heat a room or to transfer or remove heat in a air conditioning domestic system.

BRIEF DESCRIPTION OF FIGURES

Additional features and advantages of the present invention will become more clear from the following description of an embodiment made as an example without limitation in which:

FIG. 1 shows a schematic view in lateral section of the thermo-well according to the invention;

FIG. 2 shows a schematic side sectional view of a different embodiment of the thermo-well of the invention;

FIG. 3 shows a schematic view from above of the embodiment of FIG. 2;

FIG. 4 shows a block diagram of a cogeneration energy system according to the invention;

FIG. 5 shows a running diagram of a heat pump;

FIG. 6 shows a block diagram of a different embodiment of the energy cogeneration system of FIG. 4;

FIG. 7 shows a schematic view from above of a further embodiment of the thermo-well according to the invention;

FIG. 8 shows a schematic view in lateral section of the thermal coat according to the invention;

FIG. 9 shows a block diagram of a further embodiment of the energy cogeneration system according to the invention.

With reference to FIG. 1, the thermo-well of the invention, indicated as a whole with number 1, includes a case 2 that includes two side walls 3 and a bottom 4. The case 2 is sealed. The case 2 may have any shape: cube, parallelepiped, cylindrical, etc. and in particular its shape will depend on the need to increase or decrease the heat transfer with the surrounding environment. Therefore, the shape will be chosen in order to maximize surface area in those uses in which the thermo-well is not insulated to facilitate heat transfer to or from the outside, otherwise, for thermo-insulated wells, a shape that minimizes surface area must be preferred.
In one embodiment, where the thermo-well is not insulated and must have a large surface of heat transfer with the surrounding ground, the case 2 is externally covered by a suitable metal, such as a corrugated sheet, which maximizes the area of heat transfer per unit area.
The case 2 is completely buried up to several meters deep, in order to exploit the substantial homeothermia of the ground in the different seasons.
The case 2 is preferably made of concrete, both for reasons of strength and low cost, but may also be manufactured in a different material that is suitable for a long persistence under the ground level.
The case 2 is closed on the upper part by a lid 5 which has a hole to let through a vertical duct 6, which starts from the bottom 4 of the thermo-well 1 and protrudes above it to the surface S of the ground. The vertical duct 6 can be realized in the same material in which the case 2 is manufactured or in a different material and can have any shape in section. At ground level, the duct 6 includes a manhole inspection 7, while near the base it comprises one or more openings 8 which connect the inner duct 6 with the thermo-well 1.
Inside the duct 6 are housed an outlet pipe 9—connected to pumping means 11, typically a submerged recirculation pump—and an inlet pipe 10. The pipes 9, 10 are part of a closed circuit which passes through heat transfer equipment (not shown), as will be clarified later in the description.
The pumping means 11 are typically electrical pumping means and will include therefore a suitable cabling coming out of the thermo-well 1 and reaching the power supply on the surface.
The inlet pipe 10 includes an elbow portion 12, which comprises the upper portion of the thermo-well 1, under the lid 5. This elbow portion has two holes that allow the leakage of the fluid circulating inside the pipes 9, 10.
The internal part of case 2 of the thermo-well is filled with an inert material G in granular form, which is the media for the heat transfer and the heat storage inside the thermo-well according to the invention. Preferably this material has a particle size between 5 mm and 50 mm; preferably, the inert material G will consist of a mixture of grains of different size, ie 50-10 mm/10-25 mm/25-40 mm in proper ratio. More preferably, the mixture comprises about ⅓ of each of the above indicated sizes.
To fulfill both the function of heat storage and of heat transfer, the inert material G must possesses, as a whole, a high heat capacity and a high thermal conductivity.
To maximize the heat capacity and makes it as close as possible to that of water, materials that have a suitable ratio between specific heat and density should be used. Preferably, the inert material G has a specific heat of at least 0.2 kcal/kg.° C. and a density in bulk of at least 1400 kg/m³.
The inert material G has a thermal conductance, measured at room temperature, preferably higher than 0.6 Kcal/m° C., more preferably higher than 1.2 Kcal/m° C.
The inert material G is preferably selected from stones, gravel, marble or synthetic resins suitable to stay in contact with water.
The filling with the inert material G may include, in the lower and/or upper portion of the case 2, a portion of material with greater size G1, for example, a size of about 100 mm. In this way, areas of homogenization of fluid at the entrance and/or at the exit of the thermo-well 1 are formed.
Alternatively, as shown in FIG. 1, a homogenization zone 13 can be carried out by putting homogenization bells 14, arranged above the holes in the elbow portion 12 of the inlet pipe 10. An example of such homogenizing bells 14 are the igloo for loose stone foundation, commonly used in building. In this embodiment, the homogenization zone 13 does not include inert G, which has been arranged under it, instead.
FIG. 1 shows the elbow portion 12 of the inlet pipe 10 and its homogenization zone 13 in the upper portion of the thermo-well 1, but in other forms of carrying out the fluid supply could be at the bottom of the thermo-well 1 and its removal by pumping means 11 could be in the upper portion.
In using conditions, the thermo-well 1 is typically filled with a fluid, which has the characteristics of a heat carrier fluid. In FIG. 1 is indicated with L the heat carrier fluid level in the thermo-well. In this way, providing the pumping means 11 near the bottom 4, a high blowback is obtained, which decreases the power requirements of pumping means 11.
The heat carrier fluid is typically water. However, when using the thermo-well 1 in extreme climates or in applications that require extremely high or very low temperatures (eg in industrial applications in the cycle of cold or warm), water additioned, depending on the case, with suitable anti-freezing agents such as glycol and/or diathermic oils could be used. In this way, the temperature range in which the thermo-well of the invention can operate will be between −50° C. and 250° C. or higher.
As shown in the embodiment of FIG. 1, the heat carrier fluid placed in the thermo-well 1 through the inlet line 10, which has holes in the homogenization area 13, under the homogenization bells 14, fills the homogenization zone 13 and then flows through the material G and G1 as shown by arrows. In this way the heat carrier fluid transfers or takes heat from the inert material G—depending on the application—then it is collected at the bottom and, through the openings 8, enters the duct 6 which, by the principle of communicating vessels, will be filled at the same level of thermo-well 1. The pumping means 11 then collect the heat carrier fluid and provide to recirculate it through the outlet pipe 9.
Depending on the applications, the case 2 is externally insulated or not. In particular, where the thermo-well 1 is used as a storage of warm or cold, especially in use with extreme temperatures, the case should be insulated in order to use the inert material G as a way of storage for heat or cold. In other application the heat transfer between the thermo-well 1 and surrounding ground can be used, taking advantage of the good thermal conductivity of both the inert material G and the material of which the case 2 is realized. As an example, it may be convenient to quickly transfer the heat carried by the fluid or vice versa to try to uniform its temperature to the temperature of the ground, as will be shown in a number of possible carrying out forms described below. In these cases, the case 2 is not properly insulated and will have a shape that maximizes the heat transfer surface with the surrounding ground.
From the above, it is evident that the heat carrier fluid must have a good heat transfer with the inert G. To this end, it is useful that the path of the fluid is maximized, from when it comes into contact with the inert G to when it exits the thermo-well 1. It will be also important that the whole mass of inert material G is affected by heat transfer, avoiding the formation of preferential paths. For this reason the homogenization areas 13 have been arranged and the full filling of the case 2 with the heat carrier fluid has been foreseen. In general, it will be convenient that the fluid enters the thermo-well 1 at one end and exits from the diametrically opposite end.
As shown in FIGS. 2 and 3, in which all elements corresponding to those of FIG. 1 are listed with the same number, the thermo-well 101 includes a structure that maximizes the contact between the heat carrier fluid and the inert material G.
Inside the case 2 of the thermo-well 101 is arranged a chamber 120 which comprises side walls 121 which extend in height less than the side walls 3 of the case 2, in order to leave a gap between the chamber 120 and the lid 5 of the thermo-well 101.
The inlet pipe 10 extends to near the bottom of the duct 6 and the corresponding elbow portion 12 passes through the wall of the duct 6 and of the chamber 120, placing in it a distal portion 122 with one or more holes for dispensing the heat carrier fluid.
A homogenization zone 13 has been created above the holes in the inlet pipe 10, through the provision of homogenization bells 14. The homogenization bells 14 may be replaced by inert material of greater size, eg about 100 mm.
Even the area above the chamber 120 may include an homogenization zone, or by the arrangement of homogenization bells or by the arrangement of inert material having a greater size.
The case 2 and the chamber 120 are then filled with inert material G as defined above.
The shape of the chamber 120 or of the case 2 may be similar or different as needed. Preferably, the chamber 120 is placed in position substantially coaxial with the case 2, but other positions may be foreseen.
In this embodiment, the heat carrier fluid enters the chamber 120 from the bottom, then it comes back up by percolating through the inert G up to the upper edge of the side walls 121 of the chamber 120 itself, overflowing outside the chamber 120. The fluid then percolates down until it exits from the openings 8 and it is taken by the pumping means 11, providing for the recirculation.
According to this embodiment, it is possible to lengthen the path and increase the contact time between the heat carrier fluid and the inert material G, thus resulting in a better heat transfer.
In some carrying out forms, a plurality of thermo- wells 1, 101 will be arranged in series or in parallel, for use in community.
As mentioned above, the thermo-well 1, 101 of the invention comprises a closed-circuit for the circulation of the heat carrier fluid, including the inlet and outlet pipes 10 and 9 and it is interfaced with heat transfer equipments external to the thermo-well.
For example, said closed-circuit comprises a heat transfer mean coupled to the circuit of a heat pump 15 (FIG. 5).
A typical heat pump 15 with conventional characteristics comprises a compressor 16, a condenser 17, an expansion valve 18 and an evaporator 19. Inside the so created closed-circuit circulates a refrigerant fluid which, after the compression made by the compressor 16, liquefies at high pressure in the condenser 17—transferring heat—then it is expanded by expansion valve 18 and passes to gaseous state in the evaporator 19, absorbing heat from its surrounding environment. Therefore, on the condenser it will release heat while on the evaporator there will be heat removal.
In this embodiment, the thermo-well 1, 101 can be used as storage or transfer device of warm or as storage or transfer device of cold, depending on the heat transfer coupling with the condenser 17 or with the evaporator 19. It has to be highlighted that when the heat pump 15 is equipped with “inverter” it is possible to reverse the functions of the condenser and evaporator changing the direction of circulation of the refrigerant fluid. In this case, then the closed circuit of the thermo-well 1, 101 is either coupled with the condenser or with the evaporator. Otherwise, a three-way valve could be arranged along the path of the closed-circuit of the thermo-well 1, 101, to select a first path associated with the condenser side and a second path associated with the evaporator side. Thus, depending on the needs, it will be possible to store or to transfer in the thermo-well 1, 101 heat or cold simply operating on the three-way valve.
As highlighted above, it will be convenient to store thermal energy or freezing energy in the thermo-well 1, 101 to make them available for other applications, such as conditioning interior of a building or provide warm water for heating and sanitary use in times delayed with respect to production. In fact, for example, the heat pump 15 could be run at night, when the cost of energy is lower, to condition or to provide warm water during the day. In this case, the thermo-well 1, 101 will be preferably insulated.
There may be, instead, the need to promote the transfer of heat or vice versa to provide heat to the refrigerant fluid of the heat pump 15 to increase efficiency, depending on the need to cool or to warm an environment, respectively. In this case, the thermo-well 1, 101 will be preferably not insulated.
FIG. 4 shows an energy cogeneration system that uses the thermo-well according to the invention.
The cogeneration system comprises a generator 20 of electricity, operating for example through a heat engine and consumes fossil fuels or biofuels. In this case it will produce both electricity E1 and heat T1, which can be recovered (through appropriate heat transfer, not shown) for different uses.
The electricity E1 produced is sent to electricity partition equipments 21, able to send it, as needed, to an user or to a heat pump 15.
The heat pump 15 is not the type with “inverter” and it is interfaced—via heat transfer—a) on the condenser side, with the closed-circuit 22 of a thermo-well 201 for the storage of heat, and b) on the evaporator side with the closed circuit 23 of a thermo-well 301 for the storage of freezing energy.
The thermo-well 201 will provide then heat T2, while the thermo-well 301 provide freezing energy F.
In this application, the two thermo- wells 201, 301 are insulated and have a shape that minimizes the surface/volume ratio.
Alternatively, the thermo-well 201 is insulated and the other thermo-well 301 is not insulated to facilitate heat transfer and, according to the seasons, to heat or to cool the heat carrier fluid circulating inside. In this embodiment, the insulated thermo-well 201 is used to store heat in winter (interfaced with the condenser side of the heat pump 15) and to store freezing energy in summer (interfaced with the evaporator side of the heat pump 15). Given that the heat pump 15 has no inverter in this case, a first and a second circuit of recirculation will be provided, regulated by a three-way valve, which alternately connects the thermo-well 201 to the condenser side or to the evaporator side of the heat pump 15, and a third and a fourth circuit of recirculation, regulated by a three-way valve, which alternatively connects the thermo-well 301 to the condenser side or to the evaporator side of heat pump 15, as described above. In this way, it is possible to easily exchange the two thermo- wells 201, 301 with their interface with the heat pump 15, as needed.
According to the embodiment schematically shown in FIG. 7, two thermo- wells 201, 301, both insulated, are put side by side inside a third thermo-well 401 which is not insulated. In this way with a single excavation in the ground the positioning of three thermo-wells is obtained. The three thermo-wells are able to perform all the functions required by the cogeneration system, ie storage of thermal and/or freezing energy for other uses and/or transfer of thermal and/or freezing energy to increase the efficiency of the heat pump 15.
In the embodiment shown in FIG. 6, the energy cogeneration system is completely identical to the one above described in relation to FIG. 4, with the exception that the generator 20 is powered by renewable sources such as an Aeolic turbine 24—typically a micro—Aeolic power station—and/or photovoltaic panels 25. Since both systems are discontinuous, requiring the first one the presence of a sufficient amount of wind and the second one the presence of solar radiation, they can be used concurrently, eg by producing Aeolic energy during a windy night when the photovoltaic panel is inactive, while during the day the photovoltaic panel can compensate to the possible lack of wind.
In this embodiment, the only thermal energy produced is the one from the heat pump 15, stored through the thermo-well 201.
In a further embodiment, shown in FIG. 9, a heat pump 15 is, for example, driven directly from electricity from the power network. Of course, nothing prevents that the heat pump is activated by a generator as in the two previous embodiments.
The heat pump 15 is used here to condition an environment in summer, coupling the evaporator side with a heat transfer (not shown) for cooling the environment. To increase the efficiency of the heat pump 15 is therefore appropriate to maximize the heat transfer on the condenser.
Therefore, the condenser of the heat pump 15 is interfaced—by equipments of heat transfer 30—with the closed circuit 31 of a thermo-well 501 which is not insulated. In this way, under normal conditions, a transfer of heat is obtained by the thermo-well 501 as described above. It may be, however, after prolonged use and in warm climates, that a saturation temperature of the thermo-well 501, is obtained, and this will lead to a significant loss of efficiency.
It has been foreseen to connect the closed circuit 31 of the thermo-well 501 to a serpentine coil 32 placed on the wall C of a building. This connection is implemented through a three-way valve 33 which allows to select, alternatively, the connection flow between the serpentine coil 32 and the closed circuit 31 or the connection flow between serpentine coil 32 and a service circuit 34.
The coil 32 can be made with tubes, corrugated or not, possibly multi-layer, PVC (knitted, braided or metal core), polyethylene, copper, steel.
The system outlined here works as follows. During daylight hours, the heat pump heats the heat carrier fluid of the closed circuit 31 of the thermo-well 501, which will then transfer it. Such transfer may not be complete (depending on the temperature of the ground or its thermal conductivity), so the temperature of the fluid inside the thermo-well 501 will tend to rise. Meanwhile, the valve 33 closes the circuit between the serpentine coil 32 and the circuit service 34, to send the heat carrier fluid contained in the serpentine coil 32—warmed by the rays of sun falling on the wall C—to a heat transfer for using it for example to heat water for sanitary use.
Vice-versa, at night, especially in the cooler hours, the valve 33 selects the circuit between the serpentine coil 32 and the closed-circuit 31 of the thermo-well 501, facilitating the cooling of the thermo-well 501 thanks to the heat transfer surface of the serpentine coil.
In a preferred embodiment, the serpentine coil 32 is included in a thermo-coat 35 as shown in FIG. 8.
The thermo-coat 35 comprises at least one layer consisting of a ribbed sheath 36, in which the ashlars are facing the wall C of the building. This sheath may be for example a sheath of PVC, such as those used as external insulation in the foundations of buildings.
Preferably, two or three sheath 36 will be arranged, with the ashlar side facing outward or inward, but in this case with an offset position with respect to the inner layer.
Over one or more layers of ribbed sheath 36 is arranged a layer of insulating material 37, the type normally used in the insulation of walls of buildings. The insulating material 37 may be ashlar with ashlar facing inside or outside, too. Suitable materials are polyurethane and polystyrene foam.
On the layer of insulating material 37, when present, or directly on the outer layer of ribbed sheath 36, a plate with a fret section 38 is placed. The plate 38 may be made of aluminium, galvanized steel or alloys with high thermal conductivity. Optionally, the plate 38 is covered with a sheath embossed with ashlar facing outside.
The plate 38 has grooves 39 horizontally disposed, in which the serpentine coil 32 is inserted. The function of grooves 38 is twofold. First there is a concentration of the heat caught by the plate 38 on the edges of grooves 39, facilitating the heat transfer with the heat carrier fluid circulating within the serpentine coil 32. Furthermore, the space located between the plate 38 and the lower layer 37 is filled by air Ac, which, thanks to the presence of grooves 39 that block updrafts, may be considered essentially static air. Under these conditions, the air Ac trapped under the plate 38 makes a good thermal insulating function.
Suitable equipments of anchoring 40 shall fix the whole to the wall C.
Above the plate 38 is placed a grid 41, typically a conventional thermo-welded grid, and above it is spread a layer of plaster 42, preferably made of inert materials such as sand and cement with high thermal conductivity. The plaster 42 may optionally be enriched with materials with high thermal conductivity.
Conveniently, the layer of plaster 42 has thickness of the order of 3-4 cm, in order to increase the resistance to erosion and the function of acoustic insulation.
The thermo-coat 35 of the invention also comprises one or more air ducts 43 which connect the space beneath the ribbed sheath 36, in which there is the air AAC, with the outside. Typically, the duct 43 outwardly presents a grid 44. The function of these air ducts 43 is to balance the pressure between indoor air AAC and atmosphere, so that the air AAC acts as anti-condensation and protects the wall C from the mold.
In one embodiment, the layer of plaster 42 is enriched with photo-catalytic compounds, such as photo-catalytic titanium dioxide in order to carry out the action of atmospheric air purifier.
In one embodiment, the layer of plaster 42 is coated completely or only on certain portions by a layer of translucent honeycomb material (not shown), such as a POLIBOLL film used in packaging. This film has the function to let the solar radiation easily pass through, but on the opposite to reduce the heat loss by conduction from the thermo-coat 35 to the outside, thanks to the presence of cavities filled with air.
In one embodiment, the serpentine coil 32 is not present: in this case, the thermo-coat 35 plays only function of thermal insulation and possibly acoustic insulation.
The advantages of the present invention are manifold.
The thermo-well can find extensive applications in both residential and industrial sectors, either as a heat transfer device or as a storage device, using the surrounding environment in which it is immersed. The ground is in fact on average cooler in summer and warmer in winter than the atmosphere above.
It is an economic and dynamic structure, easily achievable through normal excavation. The flexible geometries makes it effective even in agro-industrial sectors; after an appropriate static testing, it can be used in setting up roof gardens on terraces, garages and underground structures in general, contributing to storage solutions for thermal energy. The artefact is a substantial response to longstanding criticism in the seasonal storage (developed in northern European countries), resulting from the huge engineering and insulating structures required for the long period. The thermo-well provides a scenario for the short term energy storage, day-night or what it is estimated to meet temporary needs, resulting in periods of limited supply from other renewable sources such as direct and indirect solar, Aeolic, hygro-thermal tenor of the environment, that perhaps become scarce for days or weeks.
The cogeneration system efficiency can be applied in residential, commercial and industrial structures as well as in many industrial processes. The invention has important economic significance and leads to savings in both construction of plants and in their management, in addition provides advantages for the reduction of environmental pollution (better use of fossil fuels). It develops, delivering equal service, lower levels of climate altering gases (GHG) released into the atmosphere. It promises the highest levels of security and lower cost (electric cars). It offers a high degree of industrialization and employment of local workers. It uses short chain products and solutions on a national basis, generally available and cheap. Other advantages are: high synergies and affinities to standards LCA, LEED, ISO, UNI; access to government incentives provided for energy efficiency and energy production from renewable sources and the EU provided incentives to reduce greenhouse gas emissions.
The thermo-coat application is extendible in both residential and industrial sectors, new or already built, by ensuring energy recovery and the protection of existing structures, acting from outside, as befitting any good criterion properties of regular use. The device allows to suddenly equalize the internal linear pressure (already in the air layer inside, indented by ashlar and opposing convected movements) to the outside, with the gap created by the first embossed sheath, thereby protecting the existing curtain walls of every opportunity to create condensation or mold in the same buffer. Limiting the replacement of oxygen and water drops drastically prerequisites to carbonation. The air used as insulation has salient advantages, in term of costs and in term of physical and technical features, not fearing any loss of performance over time, while maintaining its thermal conductivity similar to that of polyurethane and polystyrene, both of which are among the best existing insulating. The outer layer made of inert materials consists only of sand and cement and supplies, thanks to its mass, strength and a fair contribution to a natural thermal lag, which is useful both in winter and summer conditioning processes. The artefact can also be dimensioned according to acoustic insulation, increasing the mass of the outer layer.
In conclusion, the following advantages should be obtained with the present invention: 1) heat storage capacity and low cost-performance thermo-well, that can be used in a large number of applications in addition to those exemplified above, all within the normal activities of the expert in the field, 2) efficiency of the structure of the thermo-coat absorber, with emphasis on low costs and projected performance in the face of the salient blend of performance on: hygroscopicity, insulation, collection, acoustic isolation, electromagnetic isolation, product purification with photo-catalytic properties (through paint, mortar, ceramics and various mineral coatings), contribution to the thermal lag, static-structural consistency of the outer layer, 3) energy efficiency of distribution system used in the generation and cogeneration with time lag between production and employment time of the energy derived, aiming at a reasonable storage, sized to fill a day or little more delayed phase shifts (as opposed to seasonal, more structurally challenging to manage and less effective), aiming at an optimal use of surplus electricity that can be produced on site and compared to an optimal mortgage of generator sets.

Claims

1-37. (canceled)

38. A thermo-well comprising at least one buried case, an inlet duct of heat carrier fluid and an outlet duct of said heat carrier fluid, in which said case is sealed, wherein said at least one case comprises within it an inert material in granular form with which said heat carrier fluid is placed in contact to provide a heat transfer between said heat carrier fluid and said inert material.

39. The thermo-well of claim 38, wherein said inert material has a grain size between 5 mm and 50 mm

40. The thermo-well of claim 38, wherein said inert material has a specific heat of at least 0.2 kcal/kg.° C., a density in bulk of at least 1400 kg/m³and a thermal conductivity, measured at room temperature, at least 0.6 Kcal/m° C.

41. The thermo-well of claim 38 in which said inert material is selected from the group consisting of: stones, gravel, marble, synthetic resins and combinations thereof, and where said inert material is capable of staying in contact with water.

42. The thermo-well of claim 38, wherein the filling of said at least one case with said inert material comprises, in the lower and/or upper portion of the case, a portion with material having greater size to set areas of homogenization of fluid at the entry and/or at the exit of the thermo-well.

43. The thermo-well of claim 38, wherein at least one area of homogenization is carried out by arranging homogenization bells, placed above the feed zone of said heat carrier fluid in said at least one case.

44. The thermo-well of claim 38, wherein the level of heat carrier fluid in said at least on

45. Thee case is equal to or higher than the level of supply of that heat carrier fluid in another case.

46. The thermo-well of claim 38, wherein said heat carrier fluid comprises water and substances selected from the group consisting of: glycol, diathermic oils and combinations thereof, in order to avoid freezing or boiling, respectively, in a temperature range between −50° C. and 250° C.

47. The thermo-well of claim 38, wherein said case is insulated and wherein the ratio of external surface/volume is minimized.

48. The thermo-well of claim 38, wherein said case is not insulated and has a shape in which the ratio of external surface/volume is maximized.

49. The thermo-well of claim 47, wherein said case is externally covered by a plate to maximize the area of heat transfer per unit of surface.

50. The thermo-well of claim 38, wherein said at least one case comprises a bottom, side walls and a lid and comprises a vertical duct which houses said inlet and outlet pipes. wherein said duct starts from the bottom of said at least one case and protrudes above the thermo-well to the surface of ground, said duct near the base comprising one or more openings that communicate the interior of the duct with the respective case.

51. The thermo-well of claim 38, wherein said outlet pipe is connected to pumping means as a circulating submersible pump.

52. The thermo-well of claim 38, wherein inside the case is arranged a chamber which comprises side walls which extend in height to a lesser extent to that of the side walls of the case providing a gap between said chamber and said lid of the thermo-well, and in which said inlet pipe dispenses said heat carrier fluid at the base of said chamber.

53. The thermo-well of claim 38, wherein two thermo-wells are placed side-by-side in a third thermo-well which is not insulated.

54. A system for heat transfer and/or storage of thermal or freezing energy, comprising the thermo-well of claim 38, arranged in series or in parallel.

55. The system of claim 53, wherein a closed-circuit for the heat carrier fluid of said thermo-well is coupled through a heat transfer with a closed-loop circuit of a heat pump on a condenser and/or on an evaporator.

56. An energy cogeneration system comprising a generator of electricity, devices of partition of said electricity generated capable of sending said electricity, as needed, to a user or to an electric heat pump, said heat pump being interfaced via heat transfer a) on a capacitor, with a closed circuit of a first thermo-well, and/or b) on an evaporator side, with a closed circuit of a second thermo-well.

57. The system of claim 55, comprising, in addition to or instead of said first and second thermo-well, a non-insulated thermo-well, wherein the closed circuit of said thermo-well is connected with a serpentine coil arranged on the wall of a building, said connection being implemented through a three-way valve that allows alternative selection of the link flow between a serpentine coil and the closed-circuit and/or the flow connection between the serpentine coil and a circuit service.