ITMI20100458A1 - COMPACT ENERGY CENTRAL WITH AN INTEGRATED SYSTEM OF RENEWABLE SOURCES ACTING TO GUARANTEE ENERGY SELF-SUFFICIENCY TO A THERMAL SYSTEM - Google Patents

Description

DESCRIPTION

The present invention refers to systems for the production of hot water for sanitary uses and for the heating and conditioning of environments using renewable energy sources. In particular, the invention refers to an energy plant equipped with an integrated system of renewable sources capable of guaranteeing the self-sufficiency of said plants. More specifically, the aforementioned renewable sources are the irradiation of the sun and the temperature of the ground and of the water table at a convenient depth with respect to the surface of the soil.

The system according to the invention, suitable for any type of human settlement, is particularly useful for villas, apartments, condominiums and offices as the power plant that governs it is capable of self-producing all the energy needed in self-sufficient quantities.

For a long time now, research and its industrial applications have been aimed at the use of renewable energy sources, such as wind, sun, tides, and this for many reasons. In particular for the current cost of the fuel most used in the last 150 years, that is oil, the costs for the exploitation of more traditional sources such as wood, coal, water from lakes, rivers and streams, the problems of environmental pollution linked to the transport and use of oil and coal. However, even the exploitation of renewable sources presents a series of problems linked to the particular characteristics of these sources, for example the period of availability or the intermittence of their availability, or the cost and environmental impact of structures suitable for their exploitation.

All these difficulties have so far prevented the construction of completely self-sufficient plants continuously over time, as it was more convenient to accept limited self-sufficiency by integrating the plant's requests, when necessary, with the purchase of a share of the € ™ energy needed from traditional market sources.

Having said all this, the Applicant has found a new way of mutual integration of some renewable sources on the basis of which the “self-sufficiency of the plant is ensured during the entire calendar year, wherever said plant is geographically located. This self-sufficiency is achieved in particular thanks to the accumulation of energy when the energy supplied by these sources is overabundant with respect to the needs and its recovery when it is lower than the required consumption. More specifically, the alternately accumulated and recovered energy is thermal energy.

In a first aspect, the invention therefore relates to a plant for the production of domestic hot water and environmental heating / cooling which integrates solar electricity, solar thermal energy and geothermal energy.

In a second aspect, the invention also relates to a method for storing thermal energy and for its recovery implemented by integrating electricity, solar thermal energy and geothermal energy.

The present invention therefore refers, in a particular application thereof, to a system provided with an energy plant which comprises a thermal flywheel connected to a plurality of hydraulic circuits designed to supply domestic hot water, hot fluid for environmental heating, fluid separately from each other. cold for environmental cooling, and an electrical energy source for powering a plurality of electrical users connected to the system. Said flywheel is filled with a technical fluid capable of absorbing and / or transferring heat to other fluids circulating in the system. Always according to the invention, said technical fluid is heated by the addition of heat in the lower area of said flywheel, with reference to its vertical development, all as claimed in the first claim.

In any case, the present invention can be better understood from the following description and with the help of the figure attached hereto, provided for purely illustrative and non-limiting purposes, since other embodiments are in any case possible, in compliance with and in the ™ scope of definition of the aforementioned plant according to the following claims. This figure illustrates the operating diagram of the plant according to the invention, highlighting the constituent elements and their reciprocal connection. However, the constituent elements are not described in detail in their constructive aspects as they are devices and drives known in the art or in any case easily identifiable and definable by any expert in the field.

With reference to the aforementioned figure, the system first of all includes a thermal flywheel â € œAâ €, for the accumulation and distribution of fluid, which essentially constitutes the heart of the energy plant according to the invention. It substantially comprises a container â € œAâ € developed and arranged vertically, for example a cylindrical container, in which an upper zone, a lower zone and a central or intermediate zone are defined, arranged between the first two for a width including between 5% and 20% of the height â € œHâ € of the flywheel, arranged around 50% of H. The flywheel is filled with a fluid particularly suitable for absorbing and releasing heat, such as water , possibly suitably treated, for example demineralized.

This fluid is commonly referred to by technicians as â € œtechnical waterâ €. This container is connected with a plurality of hydraulic circuits for distributing the aforesaid fluid to a plurality of devices suitable for dissipating the aforementioned thermal energy.

In particular, the flywheel A contains a first heat exchanger S1 disposed in the upper zone of the container, and a second heat exchanger S2, disposed in the lower zone of the container. The SI exchanger inlet is connected to a water network, in particular the drinking water network, and its outlet supplies domestic hot water for different uses, in particular domestic.

Preferably, both the inlet and the outlet of the exchanger SI are located on the top of the flywheel A. The direction of the circulation of fluids in the exchangers and in the circuits is defined in the figure by the relative arrows.

According to the invention, the upper area of the flywheel contains high temperature fluid and is devoid of devices suitable for allowing the withdrawal of said technical fluid from this area.

Exchanger S2 occupies the lower area of flywheel A, where fluid at low temperature is found, for a height â € œhâ € not exceeding 49% of the total height H of the flywheel, and preferably between 40% and 45 % of said height; the inlet to the exchanger is located on its upper end, preferably with an inlet from the lateral surface of the flywheel, the outlet in a lower position. This S2 heat exchanger is connected by means of a hydraulic circuit 1 to a solar panel PS placed in a suitable position to optimize the operation of the system, as will be specified later, according to the solar irradiation available. Circuit 1 is filled with a suitable fluid, for example an antifreeze liquid, kept moving along the circuit, in the direction shown by the arrows, i.e. output from exchanger S2, inlet to panel PS, outlet from panel PS, inlet to exchanger S2, by means of a pump PI, preferably inserted in the section of the circuit between the exit from S2 and the entry into PS. The PS solar panel is associated with a PV photovoltaic panel which, due to the immediate solar radiation, produces electricity with which all users of the system are powered, such as the PI pump already mentioned. The electrical connections are indicated in the figure with dotted lines. In particular, the PV panel is connected through an â € œinverter Iâ €, that is a device that transforms the direct current produced by the photovoltaic cells of the panel into alternating current, both to an electrical network and to at least one of the users associated with the plant of the invention.

The association between the two PS-PV panels is purely functional in the sense that the two panels can be two different devices coupled together in the manner and for the reason mentioned, as well as a single device capable of fulfilling both functions of electricity producer and thermal energy absorber. Circuit 1 is connected to another hydraulic circuit 2 associated with a heat exchanger S3. The inlet in circuit 2 is obtained on the section of circuit 1 between the outlet from the PS panel and the inlet in the exchanger S2, the outlet from circuit 2 is located in the section of circuit 1 which connects the outlet from exchanger S2 to the inlet of the PI pump. Basically, circuit 2 is arranged in parallel with circuit 1 and constitutes a by-pass for exchanger S2; the inlet of the fluid circulating in 1 in circuit 2 is controlled by a three-way valve MI, controlled by an electronic control unit `` E '' which will be mentioned, which sends the fluid to the exchanger S2 or, alternatively, to the exchanger S3 along circuit 2 as needed, as will be explained further on.

The technical fluid contained in A feeds a hydraulic circuit 3 in which a â € œUâ € heat sink is inserted which transfers heat to the environment or to the device in which it is inserted: for example, it can be a radiant panel inserted in the floor of a room for heating that room. The aforementioned circuit 3 picks up the fluid at a point located in said central area of the flywheel A and returns it to the base of the flywheel; also in this circuit the movement of the fluid is controlled by a pump P2 inserted in the section of the circuit between the outlet from the flywheel and the inlet in the heat sink U.

The aforementioned dissipator is thermoregulated by means of a circuit branch 31 which connects the input of pump P2 with the section of circuit 3 at the output of the dissipator U. More specifically, a three-way valve M2, controlled by an electronic control unit, preferably the same control unit that controls MI sends the fluid to pump P2, mixing together the fluid arriving from flywheel A and the fluid arriving from branch 31, in variable proportions, according to need, as will be explained further below.

Finally, the fluid contained in A can be heated through a further hydraulic circuit 4 along which a heat exchanger S4 is inserted. In this case, however, the exchanger S4 receives the fluid leaving the base of the flywheel A and returns it to the flywheel A, by means of a pump P3, inserting it in the central area of the flywheel. In this area there are also an electric resistance RE, powered by the photovoltaic panel PV, and a temperature sensor T2 connected to the electronic control unit.

A heat pump B, essentially a box comprising a `` CP '' compressor, a `` C '' condenser, a `` V '' evaporator and a `` L '' lamination valve, constitutes a further integral part of the plant according to the invention. , connected in series to each other by a hydraulic circuit 5, in which an adequate fluid, for example a mixture of liquid and gas, circulates.

Furthermore, the heat pump is connected with a geothermal probe â € œGâ €, a pump P4, the aforementioned heat exchanger S3 and an additional heat exchanger S5, all connected in series to each other by a hydraulic circuit 6 in which a suitable fluid circulates, for example an antifreeze fluid.

The aforementioned heat pump uses a cold source as a heat source, located in the ground starting from a depth of 20 meters, to normally reach up to 100-150 meters, where the temperature is substantially constant throughout the year, increasing with depth (about 1 degree every 30 meters) starting from 10 - 14 degrees; alternatively, a horizontal probe buried 2 meters deep in the ground is often used. In the system diagram attached here, the condenser C is inserted in the exchanger S4, the evaporator V is inserted in the exchanger S5.

As it will be explained later, the exchanger S4 provides for the transfer of heat between the fluid circulating in the condenser C and the one circulating in the flywheel, the exchanger S5 provides for the transfer of heat between the fluid circulating in the evaporator V and that circulating in the geothermal probe .

The heat pump has a reversible operation in the sense that it can work both as a heat pump and as a cold pump. By reversing the operation of the heat pump, the condenser and evaporator functions, as will be seen later, are exchanged.

The whole control unit is controlled by at least one electronic control unit E which takes care of the management of the various system functions and uses the most convenient and immediately available energy source: in particular, it is supported by various signals coming from the system devices. , such as, for example, by the temperature sensor TI which records the temperature of the fluid at the outlet from the solar panel and by the aforementioned temperature sensor T2 which records the temperature of the fluid in the flywheel in the central area of the same.

Now note the control unit we can move on to illustrate its operation.

Under normal operating conditions, the PV photovoltaic panel produces a certain amount of electricity. This energy feeds all the users in operation in the system and if it is overabundant, the residual one is transferred to the electricity grid. Conversely, if insufficient, the power plant absorbs the necessary quantity from the network to supplement the system's consumption. The PS solar panel associated with the PV panel absorbs both the heat produced by solar radiation and the heat produced by the photovoltaic cells of the PV panel during their operation, keeping their temperature low and consequently their efficiency high. The heat absorbed by the fluid circulating in the panel is transferred to the flywheel fluid in the exchanger S2, raising its temperature. The pump PI extracts the cooled fluid from the exchanger S2 and sends it back to the PS panel to absorb new heat.

In the flywheel the fluid it contains is stratified according to increasing temperature values: in particular the fluid at a higher temperature is arranged in the upper area of the flywheel where it transfers its heat to the domestic network water in the SI exchanger.

The fluid present in the central area of the flywheel, at a lower temperature, is instead taken by the pump P2 and sent to the heat sink U where it transfers its heat, returning cooled to the base of the flywheel to receive new heat and move towards the upper layers of the fluid.

It should be noted that the withdrawal and introduction of the technical fluid from and into the central area of the flywheel keeps the fluid contained in the upper area of the flywheel in substantial rest and therefore keeps the high value of the fluid temperature in said upper area substantially constant.

According to the invention, when the control unit detects that the temperatures of the fluid in flywheel A, during the summer season, are at full capacity, through the valve MI it diverts the hot fluid arriving from the PS panel along the circuit 2 where the fluid it transfers its heat, through the exchanger S3, to the fluid leaving the exchanger S5 which is sent, through the pump P4, to the geothermal probe; more precisely, the pump P4 pushes the fluid of the circuit 6, hot due to the heat absorbed in the exchanger S3, coming from the cooling of the solar panel, and possibly also the heat absorbed in the exchanger S5, coming from the cooling of the compressed fluid circulating in V, in the cold source.

During this journey, the fluid cools, releasing all the heat to the ground surrounding the probe, thus preheating the cold source which acts as a heat accumulator which will then be transferred to the plant in the following winter season.

Still according to the invention, the heat sink device U is thermoregulated, in particular in the periods in which the heat request is neither high nor constant, by means of the pump P2 and the three-way valve M2, which functions as a mixing valve.

More specifically, the valve regulates the quantitative ratio between the temperature fluid coming from the flywheel A, through the circuit 3, and the cold one coming from the outlet of the heat sink U, through the branch 31, in order to control the global temperature of the fluid. injected by pump P2 into the heat sink U, increasing one or the other component according to the heat demand.

When the aforementioned request has stabilized so as not to require any further heat input, the M2 valve blocks the flow of fluid from the flywheel and keeps the fluid present in the closed loop made up of the M2 valve and the pump in circulation. P2 and from the heat sink U, thus by-passing flywheel A.

It would of course be possible to stop the pump P2, however, according to a preferred way of implementing the invention, it is preferred to always keep the pump in motion since the thermal equilibrium situation in the heat sink is always a temporary equilibrium situation for which the pump in movement it can react almost instantaneously to temperature variations in U, consequently piloting valve M2.

In the cold season, when solar irradiation is low, the CP compressor is put into operation: it compresses the gaseous fluid arriving from evaporator V, raising its temperature. This fluid, in the gaseous state, passing through the condenser C reacquires the liquid state by giving its heat to the cold fluid, arriving in the exchanger S4 from the base of the flywheel A, following the circuit 4.

Here the technical fluid heats up and then returns hot to the central area of the flywheel. A P3 pump keeps the fluid in circuit 4 circulating.

Meanwhile, the fluid, released from condenser C, in the liquid state at high pressure, passes through the lamination valve L, reaching the liquid state at low pressure and, in this state, enters the evaporator E. ™ evaporator the fluid evaporates due to the heat acquired by the fluid circulating in the S5 exchanger. Thus the fluid, having returned to its gaseous state, is sucked in by the compressor which compresses it again before being sent to the condenser. According to the invention, the fluid circulating in S5 can be heated in two distinct ways, used both simultaneously and separately from each other. First of all the pump P4 sucks the fluid from the cold source, through the probe G, and pushes it, along the circuit 6, into the exchanger S3 and subsequently into the exchanger S5. This fluid acquires a higher temperature than that of the cold source since, while crossing the ground following the path of the probe, it has recovered the heat stored during the hot season, as explained above. In addition to this, this fluid heats up further as it passes through the S3 exchanger. In fact, in the aforementioned cold season the hot fluid exiting the PS panel, in addition to not being able to heat the fluid of the flywheel A by itself, thus avoiding the use of the compressor, would provide a heat input to the flywheel fluid. very modest compared to that already supplied by the compressor: it is then preferred to divert it, by means of the valve MI, to the exchanger S3 where it transfers its heat to the fluid arriving from the probe, raising the temperature up to a maximum of 25 ° C, a value that is controlled by the control unit E. In conclusion, the fluid circulating in the exchanger S5 reaches a temperature significantly higher than that which it would have using exclusively the heat supplied by the cold source and therefore increases in a similar way the temperature of the fluid that evaporates in the evaporator V.

In this way, according to the invention, the efficiency of the compressor CP is increased since this compresses a preheated fluid in its circuit 5, thus raising the temperature of the compressed fluid to a higher value, effectively reducing the electrical consumption of the compressor.

The electric resistance RE, powered by the current produced by the PV panel, intervenes in extreme situations of use, when the need arises for a greater supply of thermal energy in the upper area of the flywheel, for a greater demand for domestic hot water, to supplement the heat supplied by both the solar panel and the compressor.

It should be noted that the PV panel simultaneously produces electricity and thermal energy based on light and not on the heat of the sun: thermal energy is produced by overheating the solar cells themselves and their inability to transform all light into energy electric. In practice, only about 18% of the radiant light is transformed into electrical energy, the rest is transformed into thermal energy. It should also be noted that the heating of the solar cells reduces the production of the same electricity, so that the recovery of the thermal energy, implemented by the system through the solar panel, in the system according to the invention, increases the yield of the cells of the order of about 30% and provides a non-negligible share of thermal energy that is totally free even in situations of reduced solar thermal energy.

Finally, the system according to the invention can also cool rooms during the hot season. Suppose the energy sink U is a conditioning device fed with a cold fluid. To compensate for the production of this fluid, both the operation of the P4 pump and that of the CP compressor are reversed.

Pump P4 pushes the fluid to the extremity of the probe where it assumes the temperature of the cold source and in these conditions it passes through the exchanger S5 absorbing the heat of the compressed fluid that circulates in circuit 5. In fact, the CP compressor has now reversed its operation and pushes the compressed fluid sucked by condenser C into the evaporator V

This fluid condenses by cooling and in this state passes through the condenser C, absorbing heat from the technical fluid that circulates in the exchanger S4, with consequent evaporation and return to the gaseous state. The technical fluid thus cooled, by means of a three-way valve M3 is sent along the circuit branch 41 to the pump P2 and by this is pushed into the heat sink U and then, through the circuit branch 42 again brought back into the exchanger S4 by- passing the thermal flywheel A.

At this point it can be noted that the advantageous behavior of the system according to the invention depends on the mutual coordination of all the devices of the system, without which the brilliant results made available with the invention could not be grasped. . For example, the absence of the RE electrical resistance or the failure to cool the photovoltaic panel would certainly compromise the yield of the system.

However, it should be noted that, for example, the supply of domestic water at high temperatures is permanently ensured without requiring the permanent use of expensive devices such as the compressor.

After the above, it will also be clear how the invention has made available a new and original method of reciprocal integration of different renewable energy sources in order to guarantee energy self-sufficiency for a thermal energy exploitation plant, regardless of the environmental temperature. . According to the invention, this method is characterized by the fact of accumulating the heat deriving from solar radiation in the ground during periods of overabundance of said heat, compared to the needs of said system, to recover it for use in said system during the periods of shortage of this heat. Still it can be observed that the photovoltaic source could be coupled or replaced with a wind source, with low or zero environmental impact, however losing in this way a share of the advantages obtained with the previously illustrated solution.

The invention described offers important qualitative, economic and environmental advantages, suitable for reducing pollution.

Thanks to the mutual integration of three renewable energy sources, solar light and heat, geothermal heat, and thanks to the conservation and subsequent recovery of heat through the heat pump, the power plant can have considerable quantities of constant and free electrical and thermal energy, so as to guarantee the energy and economic self-sufficiency of the plant regardless of the particular geographical location, in warm countries or with a temperate or even cold climate, and from the changing of the seasons. The renewable sources used, the equipment and the method of their use make the plant free from emissions of any kind, particularly harmful, into the atmosphere and into surface and underground waters. The construction costs of the plant are limited as technical devices known for some time in the art are used in a new way and therefore with high quality and reliability characteristics. Furthermore, the particular arrangement of the hydraulic circuits connected to the thermal flywheel achieves efficiency values of the system which are significantly higher than those of known systems. In conclusion, the construction cost of the plant can be amortized in a short time and the management cost makes it particularly convenient.

In this description, not all the possible structural and dimensional alternatives to the specifically described embodiments of the invention have normally been illustrated: in fact it did not seem necessary to expand into the constructive details of the system of the invention as each technician of the invention arte, after the instructions given here, will have no difficulty in designing the most advantageous technical solution by choosing the right materials and dimensions. However, these variants are understood to be equally included in the scope of protection of the present patent, as these alternative forms in themselves can be easily derived from the description made here of the relationship that binds each embodiment with the result that the invention intends. obtain.

Claims (15)

CLAIMS 1. Energy plant for the exploitation of renewable sources for the production of thermal, electrical and cooling energy for industrial and domestic purposes, comprising a thermal flywheel, accumulator and fluid distributor, a plurality of devices designed to dissipate said thermal, cooling and electric, a plurality of hydraulic circuits for the circulation of fluids suitable for storing and transferring heat between said flywheel and said devices, and a plurality of drives suitable for producing said circulation of fluids, characterized in that said flywheel comprises a container of fluid vertically arranged, filled with a technical fluid, having three distinct zones in vertical succession from bottom to top, a lower zone of low-temperature fluid, a central zone and an upper zone of high-temperature fluid, said upper zone being devoid of of devices suitable for allowing the withdrawal of said technical fluid from said area. 2. Power plant according to claim 1, characterized in that said flywheel contains in said upper zone a first heat exchanger inserted on the drinking water distribution network. 3. Power plant according to claim 1, characterized in that said flywheel contains in said lower zone a second heat exchanger connected in series by means of a first hydraulic circuit with a solar thermal panel. 4. Energy plant according to claim 3, characterized in that said solar thermal panel constitutes a cooling device of a photovoltaic solar panel associated with it. 5. Power plant according to claim 3, characterized in that said second heat exchanger is connected in parallel with a third heat exchanger inserted in series on a second hydraulic circuit, by-pass for said second exchanger. 6. Power plant according to claim 1, characterized in that said flywheel is connected to a heat sink by means of a third hydraulic circuit. 7. Power plant according to claim 6, characterized in that said third hydraulic circuit comprises a by-pass connection between the inlet and outlet of said heat sink. 8. Power plant according to claim 1, characterized in that said flywheel is connected to a fourth heat exchanger by means of a fourth hydraulic circuit. 9. Power plant according to claim 8, characterized in that said fourth heat exchanger is connected to a fifth heat exchanger by means of a fifth hydraulic circuit which comprises a fluid compressor. 10. Power plant according to claim 9, characterized in that said fifth heat exchanger is inserted, in series with said third heat exchanger, in a sixth hydraulic circuit comprising a heat pump. 11. Method for integrating different renewable energy sources together to ensure energy self-sufficiency for a thermal energy exploitation plant, regardless of the environmental temperature, including the phase of integrating together solar radiation and geothermal heat, characterized by made of accumulating the heat deriving from solar radiation in the ground during periods of overabundance of said heat, with respect to the needs of said system, to recover it for use in said system during periods of lack of said heat. 12. Method according to claim 11, characterized by the fact of accumulating said excess heat by recovering the heat produced by a photovoltaic panel. 13. Method according to claim 11, characterized by using said previously accumulated heat to heat the fluid circulating in a geothermal pump. 14. Method according to claim 11, characterized by using said previously accumulated heat to produce evaporation of a fluid sent for compression. 15. Method according to claim 11, characterized by using said previously accumulated heat to preheat a fluid intended for compression.