US20100251734A1

US20100251734A1 - Plant for heat-regulating a first fluid and a second fluid used for air-conditioning premises

Info

Publication number: US20100251734A1
Application number: US12/718,708
Authority: US
Inventors: Tarcisio Ghelfi; Alessandro Pozzi
Original assignee: EUBOIS SpA
Current assignee: EUBOIS SpA
Priority date: 2009-03-09
Filing date: 2010-03-05
Publication date: 2010-10-07
Also published as: EP2406551B1; WO2010102912A1; EP2406551A1; ITMI20090346A1; IT1393132B1

Abstract

A plant for heat-regulating a first fluid and a second fluid for the air-conditioning of premises, including a source of primary thermal energy capable of providing a hot fluid, an absorption refrigerating machine supplied with the primary thermal energy, a first auxiliary circuit for recirculating the first fluid, which exits hot from the absorption machine and returns cold into the same machine, a second auxiliary circuit for recirculating the second fluid, which exits cold from the machine and returns hot into the same machine, there being provided a heat-exchange mass capable of supplying/absorbing heat, means capable of connecting alternately the first auxiliary circuit or the second auxiliary circuit of the absorption machine to the thermal mass or to the user appliances for the associated heat exchange, the primary thermal energy being hot water.

Description

CROSS-REFERENCE TO RELATED ACTIONS

This application claims foreign priority benefits under 35 U.S.C. §119(a)-(d), or 365(b) to Italian Patent Application No. MI2009A 000346, filed Mar. 9, 2009, which is incorporated by reference herein in its entirety.

BACKGROUND

It is known, in the technical sector relating to air-conditioning of domestic and/or industrial premises, to use air-conditioning machines which, by means of a refrigerating cycle, are able to cool an environment by drawing heat from the inside and dissipating it externally. These machines typically function by means of an electrical apparatus (e.g., a compressor) which is able to perform the compression/expansion operations used during the machine operating cycle. These air-conditioners may operate as heat pumps, namely supplying heat into the internal environment by means of reversal of the cooling fluid cycle, performed by means of reversible valves. These heat pumps, however, are typically unable to achieve a high operating efficiency, and may suffer other adverse performance effects due to being positioned outside the premises, (i.e. exposed to high summer temperatures and low winter temperatures).
In addition to heat pumps, absorption machines are also known, i.e. apparatus inside which the cooling fluid formed by a special solution comprising a solute and a solvent circulates. The solution is typically circulated through a first high-pressure zone where, by supplying thermal energy from the outside (generator), evaporation of the solvent takes place, the latter reaching a condenser inside which it changes from the gaseous state into the liquid state, releasing heat to an external fluid (water or air). At this point the cooling liquid passes to an evaporator at a pressure much lower than that of the condenser and starts to draw heat from an external liquid (water) to be cooled, the cooling vapour is absorbed by the concentrated solution and passes to the absorber from where it is conveyed to the generator via a pump, while the condensation and dilution heat is removed by means of cooling water.
All the machines described above typically have intrinsic limitations in terms of efficiency which can result in poor performance since these machines are essentially designed to function either as summer air-conditioners or as winter heaters.

SUMMARY

In general, in an embodiment, the invention can provide a plant for heat-regulating first and second fluids for air-conditioning of a premises, the plant including a source of primary thermal energy configured heat at least one of the first and second fluids to provide a heated fluid, an absorption refrigerating machine configured to receive the heated fluid, a first auxiliary circuit configured to recirculate the first fluid, which exits hot from the absorption machine and returns cold into the absorption machine, a second auxiliary circuit for recirculating the second fluid, which exits cold from the absorption machine and returns hot into the absorption machine, a heat-exchange mass configured to at least one of supply and absorbing heat, and a valve configured to connect alternately at least one of the first auxiliary circuit and the second auxiliary circuit of the absorption machine to at least one of the thermal mass and a user appliance for the associated heat exchange, wherein at least one of the first and second fluids comprises water.
Implementations of the invention may provide one or more of the following features. The absorption machine is of the type with a solution formed by water and lithium bromide. The absorption machine is of the type with a solution formed by water and silica gel. The plant further comprises a heat exchanger arranged between the first auxiliary circuit and the user appliance. The plant further comprises a heat exchanger arranged between the second auxiliary circuit and the heat-exchange mass. The valve is a three-way valve. The absorption machine is configured to operate with water at a temperature ≧60° C. The user appliance comprises an air-conditioning plant. The user appliance comprises a heating plant.
Implementations of the invention may also provide one or more of the following features. The primary thermal energy source is a boiler configured to operate using fuel and is configured to operate with hot water and cold water. The primary thermal energy source is a mixed generator of thermal and electrical energy. The primary thermal energy source is an absorber of thermal solar energy. The primary thermal energy source is a high-enthalpy geothermal source. The primary thermal energy source is at least one of a technological and a remote heating plant. The heat-exchange mass is a low-enthalpy geothermal source. The heat-exchange mass is a hydrothermal source. The heat-exchange mass is an absorber of thermal solar energy.
In general, an embodiment, the invention can also provide a method of using a plant as a heat pump.
Various aspects of the invention may provide one or more of the following capabilities. Summer/winter air conditioning of a premises can be accomplished. Operating efficiency can be improved over prior techniques. CO₂emissions can be reduced over prior techniques. These and other capabilities of the invention, along with the invention itself, will be more fully understood after a review of the following figures, detailed description, and claims.

BRIEF DESCRIPTION OF THE FIGURES

Details may be obtained from the following description of a non-limiting example of embodiment of the subject of the present invention provided with reference to the accompanying drawings in which:

FIG. 1 shows a schematic diagram of a heat-regulating plant according to the present invention during summer-time operation as an air-conditioner;

FIG. 2 shows a schematic diagram of a heat-regulating plant according to the present invention during winter-time operation as a heat pump;

FIG. 3 shows a schematic diagram of a plant according to the present invention complete with flow deviation means for double alternating operation;

FIGS. 4 a-4 e show examples of embodiments of a means for generating primary thermal energy to be supplied to the plant; and

FIGS. 5 a-5 d show examples of embodiments of a heat-exchange mass.

DETAILED DESCRIPTION

Embodiments of the present invention relate to a plant for heat-regulating a first fluid and a second fluid that can be used for the summer/winter air-conditioning of premises. Embodiments of the invention can be configured to provide a plant for heat-regulating fluids such that they can be used while maintaining a high operating efficiency for both operating cycles, i.e. air-conditioning and heating within a wide range of temperatures (e.g., which may vary from a few tens of degrees below zero (Celsius) to a few tens of degrees above zero (Celsius)). In addition, it is also desired that the plant should be able to function with substantially zero emission of CO₂. In connection with this problem it is also desired that this plant should have small dimensions, be easy and inexpensive to produce and assemble and be able to be installed easily at any user location. Other embodiments are within the scope of the invention.
These results can be achieved by a plant for heat-regulating a first fluid and second fluid which can be used for the air-conditioning of premises and which preferably includes i) a source of primary thermal energy capable of providing a hot fluid, ii) an absorption refrigerating machine supplied with the hot fluid and preferably including a first auxiliary circuit for recirculating the first fluid which exits hot from the absorption machine and returns cold into the same machine, iii) a second auxiliary circuit for recirculating the second fluid which exits cold from the machine and returns hot into the same machine, iv) a heat-exchange mass configured to supply/absorb heat, v) means (e.g., a valve such as a three-way valve) capable of connecting alternately the first or the second auxiliary circuit of the absorption machine to the thermal mass or to the user appliances for the associated heat exchange, and vi) the primary hot fluid is preferably water.
FIG. 1 shows an example of the plant according to the invention in a simplified form during summer operation as a cold-fluid supply system for use in air-conditioners. The heat-regulating plant preferably includes a source 10 of primary thermal energy configured to supply a hot fluid 1C (e.g., hot water) preferably at a temperature of ≧60° C. to an absorption refrigerating machine 20, preferably of the type with a solution formed by water (e.g., cooling H₂O) and lithium bromide (LiBr) or H₂O and silica gel.
The absorption refrigerating machine 20 preferably includes a generator 21, which is supplied with hot H₂O (e.g., 1C) so as to cause boiling of the solution H₂O—LiBr which, upon boiling, releases water vapour. The water vapour preferably passes to a condenser 22 in which the vapour can condense, freeing heat which can be absorbed by a first auxiliary circuit 30 for recirculating a first fluid which exits hot (e.g., 2C) and returns cold (e.g., 2F) into the absorption machine so as to be able to absorb heat again. The refrigerating machine 20 also preferably includes an evaporator 23 in which the pressure is preferably much lower than that of the condenser 22 and an inside which the cooling liquid can absorb heat from a second auxiliary circuit 40 inside which a second fluid recirculates and exits cold (e.g., 3F) from the evaporator 23 and returns hot (e.g., 3C) so as to release heat to the evaporator. The refrigerating machine also preferably further includes an absorber 24 into which the cooling vapour can return and can then absorbed again by the solute of LiBr which can be diluted again and can be pumped to the generator 21 for a new cycle. Preferably, cold H₂O (e.g., 4F) recovered, for example from 2F, is also supplied to the absorber 24.
According to preferred embodiments, it is envisaged that user appliances, which may be a (summer) air-conditioning plant 61 or a (winter) heating plant 62, are connected to a heat exchanger 60 and that a second heat exchanger 51 is connected to a heat-exchange mass 50 capable of supplying/absorbing heat depending on the type of summer/winter operation of the plant.
With the configuration described above, the air-conditioning plant can operate in the following modes:

Exemplary Summer Mode (FIG. 1)

In this case the plant preferably supplies the air-conditioner 61 with cold fluid. Thus, it is envisaged that cold H₂O (e.g., 3F) supplied from the second auxiliary circuit 40 of the absorption machine 20 enters into the heat exchanger 60 of the user appliances 61 and hot H₂O (e.g., 3C) exits therefrom and returns to the auxiliary circuit in order to supply the evaporator 22 and maintain the cycle of the machine 20. Hot H₂O (e.g., 2C) supplied from the first auxiliary circuit 30 of the absorption machine 20 enters into the heat exchanger 51 of the thermal mass 50 and cold H₂O 2F exits therefrom, returning to the auxiliary circuit in order to supply the condenser 23 and maintain the cycle of the machine 20. In this condition the thermal mass 50, which is at a temperature lower than that of the fluid of the first auxiliary circuit circulating inside the exchanger 51, preferably absorbs heat and delivers cooled fluid.

Exemplary Winter Mode (FIG. 2)

In this case the plant preferably supplies the user heating plant 62 with hot fluid. Thus, it is therefore envisaged that hot H₂O (e.g., 2C) supplied from the condenser 22 of the absorption machine 20 enters into the heat exchanger 60 of the user appliances 62 and cold H₂O 2F exits therefrom and returns to the condenser 22 in order to maintain the cycle of the machine 20. Cold H₂O (e.g., 3F) supplied from the condenser 23 of the absorption machine 20 enters into the heat exchanger 51 of the second auxiliary circuit 40 and hot H₂O 3C exits therefrom and returns to the condenser 23 in order to maintain the cycle of the machine 20. In this condition the thermal mass 50, which is at a temperature higher than that of the fluid circulating in the second auxiliary circuit 51, preferably releases heat and delivers a heated fluid.
As schematically shown in FIG. 3, the plant can be provided with three- way valves 71, 72, 73, 74 arranged along the fluid paths of the auxiliary circuits, e.g., the primary circuit 30 and secondary circuit 40, so as to be able to determine the different summer/winter operation, suitably causing opening/closing of the said valves in order to switch between the path of the fluid 2C-2F of the first auxiliary circuit 30 and the path of the fluid 3F-3C of the second auxiliary circuit 40.
The valves 71, 72, 73, 74 and their operating mode are of the conventional type and within the competence of the person skilled in the art and, although illustrated, will therefore not be described in detail below. Replacement of said valves with equivalent controllable means also lies within the competence of the person skilled in the art. According to one embodiment, it also envisaged (e.g., as shown in FIGS. 4 a-4 d) that the H₂O supplied as the primary energy source to the absorption machine 20 may be obtained in different forms or ways, such as:

- a boiler 10 (as shown in FIG. 4 a) supplied with fuel 11 and from/into which hot water (e.g., 1C)/cold water (e.g., 1F) exits/enters.
- a mixed generator 110 of thermal energy and electrical energy which, supplied by fuel 111, delivers hot water (e.g., 1C) and receives cold water (e.g., 1F) and may also supply electrical energy from the mains R;
- an absorber 210 of thermal solar energy (e.g., FIG. 4 c);
- a high-enthalpy geothermal source 310 such as a thermal source (e.g., FIG. 4 d);
- thermal energy recovered from a technological and/or remote heating cycle (e.g., FIG. 4 e).

According to one embodiment, it also envisaged (e.g., FIGS. 5 a-5 d) that the heat-exchange mass may be obtained using different methods such as:

- a low-enthalpy geothermal source 50 consisting of groundwater wells 51 in which the delivery ducts 51 a and take-off ducts 51 b are immersed (e.g., FIG. 5 a);
- a low-enthalpy geothermal mass 150 in which closed circuit probes for delivery 151 a and take-off 151 b are immersed (e.g., FIG. 5 b);
- a hydrothermal source 250 in which the delivery ducts 251 a and take-off ducts 251 b are immersed (e.g., FIG. 5 c);
- an absorber of thermal solar energy 350 to which delivery ducts 351 a and take-off ducts 351 b are connected (e.g., FIG. 5 d).

It is therefore clear how, with the plant according to an embodiment of the invention, it is possible to use an absorption refrigeration machine for supplying a cold fluid for summer air-conditioning, also as a so-called heat pump for winter heating, with a substantial increase in the overall efficiency of the plant and without the substantial emission of CO₂into the atmosphere, the primary energy for climate control being provided without operation-related combustion.
Moreover, owing to the possibility of being able to use in a closed circuit naturally available heat exchange masses and produce primary thermal energy by means of low-cost devices, it can be possible to achieve substantial savings with regard to management of the plant.
Although described in connection with certain constructional forms and certain preferred examples of embodiment of the invention, it is understood that the scope of protection of the present patent is defined solely by the following claims.
Further, while the description above refers to the invention, the description may include more than one invention.

Claims

1. A plant for heat-regulating first and second fluids for air-conditioning of a premises, the plant comprising:

a source of primary thermal energy configured heat at least one of the first and second fluids to provide a heated fluid;

an absorption refrigerating machine configured to receive the heated fluid;

a first auxiliary circuit configured to recirculate the first fluid, which exits hot from the absorption machine and returns cold into the absorption machine;

a second auxiliary circuit for recirculating the second fluid, which exits cold from the absorption machine and returns hot into the absorption machine;

a heat-exchange mass configured to at least one of supply and absorb heat; and

a valve configured to connect alternately at least one of the first auxiliary circuit and the second auxiliary circuit of the absorption machine to at least one of the thermal mass and a user appliance for the associated heat exchange,

wherein at least one of the first and second fluids comprises water.

2. The plant according to claim 1, wherein the absorption machine is of the type with a solution formed by water and lithium bromide.

3. The plant according to claim 1, wherein the absorption machine is of the type with a solution formed by water and silica gel.

4. The plant according to claim 1, further comprising a heat exchanger arranged between the first auxiliary circuit and the user appliance.

5. The plant according to claim 1, further comprising a heat exchanger arranged between the second auxiliary circuit and the heat-exchange mass.

6. The plant according to claim 1, wherein the valve is a three-way valve.

7. The plant according to claim 1, wherein the absorption machine is configured to operate with water at a temperature ≧60° C.

8. The plant according to claim 1, wherein the user appliance comprises an air-conditioning plant.

9. The plant according to claim 1, wherein the user appliance comprises a heating plant.

10. The plant according to claim 1, wherein the primary thermal energy source is a boiler configured to operate using fuel and is configured to operate with hot water and cold water.

11. The plant according to claim 1, wherein the primary thermal energy source is a mixed generator of thermal and electrical energy.

12. The plant according to claim 1, wherein the primary thermal energy source is an absorber of thermal solar energy.

13. The plant according to claim 1, wherein the primary thermal energy source is a high-enthalpy geothermal source.

14. The plant according to claim 1, wherein the primary thermal energy source is at least one of a technological and a remote heating plant.

15. The plant according to claim 1, wherein the heat-exchange mass is a low-enthalpy geothermal source.

16. The plant according to claim 1, wherein the heat-exchange mass is a hydrothermal source.

17. The plant according to claim 1, wherein the heat-exchange mass is an absorber of thermal solar energy.

18. A method of using the plant of claim 1 as a heat pump.