Patent Description:
Mechanical vapor recompression (MVR) or mechanical vapor compression (MVC) are two similar methods applying pressure/volume work to water vapor, in order to increase its enthalpy thereby superheating the steam. The rationale behind is that heating already formed vapor costs comparatively little energy comparing to generating new pristine vapor. In order to successfully enable the recuperation of the evaporation heat, which constitutes the majority of the heat into the system, a positive and significant temperature difference between the superheated steam and the recipient medium, driving the re-flux of energy in the reverse direction, is needed to become established. This is the main reason for steam (re)compression.

An MVR-unit usually comprises an evaporator, where the evaporation of a working medium takes place, a condenser, where the condensation takes place, a compressor that compresses the steam from the evaporator to a superheated state, a heating unit for initiating the evaporation process in the evaporator, and a control system that monitors and controls the process.

Below some patent documents within the technical field of MVR will be briefly discussed. In the <CIT> a system and a method is described for liquid treatment by mechanical vapor recompression comprising a fixed fluid-tight evaporator housing with improved characteristics regarding the heat exchange between heated vapor-containing volume and recompressed heating vapor-containing volume.

<CIT> describes a process water distillation plant comprising a control device arranged to control the supply of energy from an energy source into the process water distillation plant depending on the progress of the distillation process in the process water distillation plant.

In <CIT> a system for energy recycling using mechanical vapor recompression in combined chemical process is described.

<CIT> describes a robust mechanical vapor recompression arrangement comprising a compound turbine system.

In<NPL> is disclosed use of MVR technology.

In <CIT> is disclosed a compression absorption heat pump.

The above mentioned documents describe systems and methods where mechanical vapor recompression is used. However, by applying their detailed knowledge of MVR, the inventors have identified and realized further applications and utilizations of the MVR-technology, not presently known.

The object of the present invention is to use the heat generating capabilities that the processes Mechanical Vapor Recompression (MVR) and Mechanical Vapor Compression (MVC) utilize and possess. These said, already known, processes utilize the fact that compression of water vapor (steam) leads to an increase of temperature of the compressed steam. In energy terminology; the increase of thermal energy, of the steam, exceeds the energy needed to induce the necessary pressure/volume work of the said steam. In other words; the coefficient of performance (COP) or ratio between heat generation to energy insertion, of the steam/compression work, exceeds unity. As discussed above, this has already been used today as a way to treat water in a evaporation-vapor compression-condensation loop, e.g. in desalination, whereby the heated steam leads water to boil and evaporate.

However, the applications of the said processes are most often desalination or purification of contaminated water. Since the process involves boiling, evaporation and condensation, the condensate is both pure and desalinated. Besides, it is also hot (around <NUM> if the process takes place in atmospheric pressure). To date, the relatively high temperature of the condensate has not been utilized as a primary result of the process. Rather, the high temperature of the condensate has historically always been used to pre-heat the working liquid, to become treated in the MVR process, in an effort to increase the internal efficiency of the MVR/MVC processes.

The inventors have realized a further and a very beneficial application of the MVR-technology. The core of the present invention is that no-one has previously used the hot temperature working liquid, in particular the condensate of the working liquid, (typically <NUM>), for heating purposes of external objects or spaces, such as buildings, or in heat consuming industrial processes such as absorption chilling. In other words, the uniqueness of the energy system and method according to the present invention, is to utilize the MVR/MVC process as a way to generate hot working liquid which is used to heat external objects or spaces (such as buildings or industrial processes), and not, as in the above discussed known applications of the MVR-technology, to increase the internal efficiency of the MVR/MVC process.

An essential aspect of the present invention, as defined by the independent claims, is the focus on utilization of heat and not the pure condensate as such. Although it is technically possible, it is not a primarily interest to tap off the condensed water. Therefore, it is advantageous for the process to run in a "closed loop", whereby the working liquid, after exchanging parts (or the entirety) of its heat energy to an external object such as a building, via a heat exchanger or directly, goes back into the MVR process. However, as mentioned above, one could also imagine where parts of the working liquid is tapped off for particular reasons, and utilized as hot, desalinated water, although this, unlike the closed loop process, requires new water (or any other liquid used in the process) to be added to the process. For most purposes of heating of industrial processes or buildings, e.g. district heating, and heating of individual houses, this is neither desired, nor practical, so therefore, the solution defined by the appended claims primarily utilizes a closed loop.

Thus, it is worth emphasizing that the object of the present invention and the primary goal for the claimed energy system and method is to produce a working liquid (preferably hot water) with high efficiency, for external use.

The working fluid resulting from the MVR/MVC process is particularly suitable for heating purposes since it consists of distilled and desalinated water with low corrosivity - a necessary prerequisite for heating systems since radiators, heat exchangers and transportation pipelines are usually ferrous. The solution provides thus a new use of the MVR-technology, as a way to generate e.g. hot water of suitable quality, for the purpose that generated hot water releases part of its energy to external processes and objects, e.g. buildings, e.g. for heating purposes.

The above object is achieved by the energy system and the method according to the independent claims.

Preferred embodiments are set forward by the dependent claims.

According to a first aspect of the invention, the object is achieved by an energy system according to claim <NUM>. Thus, the invention relates to an energy system arranged to generate and to use thermal energy, where the energy system comprises a mechanical vapor recompression (MVR) unit, wherein thermal energy of a working liquid obtained during an MVR process performed by the MVR unit is utilized externally of the energy system, preferably for heating processes or objects.

The energy system comprises at least one liquid line where the working liquid flows. This, at least one, liquid line is arranged in a configuration outside the energy system, preferably in a closed loop configuration, and provides energy to consumers for applicable use. In this embodiment no heat exchanger (neither arranged inside nor outside of the energy system) is required for heat exchanging the working liquid with an external working fluid. Instead the working liquid, flowing in the at least one liquid line, carries the thermal energy generated by the MVR-unit, to the energy consumers, by itself, and, preferably, returns to the energy system in a closed loop configuration. This is advantageous as it probably provides the highest energy transfer efficiency a MVR-process can produce. A closed loop configuration is often preferred, however, there are applications where parts of the working liquid may be tapped off from the liquid line and used, e.g. if hot water is needed. In that case a pipe is provided to replace the tapped off volume of the working liquid.

In another embodiment, the energy system comprises at least one secondary heat exchanger arranged for heat exchange between the condensed working liquid flowing in an at least one liquid line and an external working fluid (i.e. a gas or a liquid) flowing in an at least one external fluid line to use thermal energy generated by the MVR-unit. In this embodiment, the condensed working liquid flows in a separate closed loop configuration. This is advantageous as it provides a highly efficient and flexible MVR-process.

The energy system comprises a mechanical vapor recompression MVR unit comprising:.

The MVR-unit comprises at least one liquid line arranged in connection to the condenser and via an external thermal energy consumer to the primary heat exchanger for transport of the working liquid back to the primary heat exchanger for re-evaporation in the primary heat exchanger. Because the at least one liquid line is arranged in connection to the condenser and to the primary heat exchanger for transport of the condensed working liquid back to the primary heat exchanger for re-evaporation in the primary heat exchanger, the working liquid is arranged to circulate in a closed loop. The condensed working liquid, having transferred some of its energy to the external heat consumer, is transported back to the primary heat exchanger in a closed loop, substantially with no mass losses. This enables a way of efficient energy recuperation since less energy is needed to evaporate the working liquid circulating in a closed loop comparing to the known systems.

The working liquid circulating in a closed loop is an advantageous design of an MVR-unit because historically, in one application, the MVR technology has been used to produce desalinated and distilled water for e.g. drinking purposes or industrial purposes, where the condensed working liquid (that can be water) has been used as a product from MVR. The closed loop arrangement of the working liquid enables use of the MVR-unit as a high-efficient producer of thermal energy to be used outside the MVR-unit. According to one embodiment, the condensed working liquid is not sent out as it is done according to previous solutions, e.g. to produce drinking water or purified water for industrial applications, but is essentially reused in the primary heat exchanger.

In one embodiment, the energy system comprises at least one secondary heat exchanger arranged for heat exchange between the condensed working liquid flowing in the at least one liquid line and the external working fluid flowing in the at least one external fluid line Thus, the thermal energy generated by the MVR-unit according to the present invention is used in an efficient way. Firstly, by transferring the thermal energy to the external working fluid, and secondly, by using the external working fluid directly in an external system, such as an energy system or industrial system, and/or by heat exchanging and/or mixing the external working fluid with an additional working fluid from an external system. There are no limitations regarding the external system that can utilize thermal energy generated by the MVR-unit. Any systems where thermal energy from a liquid or gas carrier is of interest, can be connected to the MVR-unit. For example, thermal energy generated by the MVR-unit can be used in district heating, for heating of buildings, as energy storage, for industrial processes or similar, but also in airborne heating systems via an liquid to air heat exchanger.

A further advantage of the system according to present invention is that the energy system with the MVR-unit may be located at the desired location for utilization of thermal energy generated by the MVR-unit. The energy system with the MVR-unit may be arranged as a mobile system.

In one further embodiment, the MVR-unit comprises a common pressure-tight enclosure and wherein at least the primary heat exchanger and the condenser are arranged within the common pressure-tight enclosure. Thus, a compact-design MVR-unit is provided enabling arranging at least the primary heat exchanger and the condenser within the common pressure-tight enclosure. Mobility of the MVR-unit and of the energy system is thereby improved. Further, risk for leakage between the primary heat exchanger and the condenser is reduced.

According to a second aspect of the invention the object is achieved by a method according to the independent method claim.

Thus, the object is achieved by a method of operating an energy system, where the system is defined by at least the features of appended independent claim <NUM>, for using thermal energy generated by a mechanical vapor recompression (MVR) unit. The method comprises utilizing externally said energy system, thermal energy of a working liquid obtained during an MVR process performed by the MVR-unit, preferably for heating processes or objects.

The energy system comprises at least one liquid line where the working liquid flows, and the method comprises arranging the at least one liquid line in a configuration outside the energy system, preferably in a closed loop configuration, and providing it to energy consumers for any applicable use.

This is advantageous as it probably provides the highest energy transfer efficiency a MVR-process can produce, as no external heat exchanging is required, and thus, the thermal energy of the working liquid may be efficiently obtained.

The method comprises heat exchanging the condensed working liquid with an external working fluid to use thermal energy generated by the MVR-unit. Because, according to this embodiment, the working liquid is transported back to the primary heat exchanger for re-evaporation in the primary heat exchanger, the working liquid is arranged to circulate in a closed loop. The condensed working liquid, deprived by external energy consumer of some of its energy, is transported back to the primary heat exchanger in a closed loop, substantially with no mass losses. This enables a new way of efficient energy recuperation since less energy is needed to evaporate the working liquid circulating in a closed loop.

Further, because the method preferably comprises the step of heat exchanging the working liquid with the external working fluid to use thermal energy generated by the MVR-unit, the thermal energy generated by the MVR-unit according to the present invention is used in an efficient way. Firstly, by transferring the thermal energy to the external working fluid, and secondly by using the external working fluid directly in an external system, such as an energy system or industrial system, and/or by heat exchanging the external working fluid with an additional working fluid of an external system.

There are no limitation regarding the external system that can utilize thermal energy generated by the MVR-unit. Any systems where thermal energy from a liquid or gas carrier is of interest, can be connected to the MVR-unit. For example, thermal energy generated by the MVR-unit can be used in district heating, for heating of buildings, as energy storage, for industrial and other technical processes or similar, and liquid to liquid heat exchanging or liquid to air heat exchanging.

Preferably, the working liquid is water, and the external working fluid is a liquid and/or a gas. Thus, for example oil, water or air can be used as the external working fluid.

Accordingly, a method for using thermal energy generated by a mechanical vapor recompression (MVR) unit is provided and thereby the above-mentioned object is achieved.

The energy system will now be described in detail with references to the appended figures. Throughout the figures the same, or similar, items have the same reference signs.

Moreover, the items and the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention.

In the figures, the arrows illustrate the flow direction in the respective line.

Within the application the expression working liquid should be interpreted as a working liquid used and obtained during the MVR process, as a condensate of the working liquid, where the working liquid is in a boiling or heated state.

According to the invention, an energy system <NUM>, <NUM>', <NUM>" is provided, arranged to generate and to use thermal energy. The energy system comprises a mechanical vapor recompression (MVR) unit <NUM>, wherein thermal energy of a working liquid obtained during an MVR process performed by the MVR-unit is utilized externally the energy system, preferably for heating processes, spaces or objects.

According to one embodiment, illustrated by <FIG>, the energy system <NUM>" comprises at least one liquid line <NUM>" where the working liquid flows. The at least one liquid line is arranged in a configuration outside the energy system, preferably in a closed loop configuration, which is illustrated in <FIG>, and provided to energy consumers for any applicable use. The thermal energy provided to the outside energy consumers is schematically indicated by arrows. In a variation of this embodiment, parts of the working liquid are tapped off from the liquid line and used for external purposes, e.g. if hot water is needed. In that case a pipe <NUM> is provided to replace the tapped off volume of the working liquid.

According to embodiments illustrated by <FIG>, the energy system <NUM>, <NUM>' comprises at least one secondary heat exchanger <NUM> arranged for heat exchange between the working liquid flowing in an at least one liquid line <NUM>, <NUM>' and an external working fluid (liquid or gas) flowing in at least one external fluid line <NUM> to use thermal energy generated by the MVR-unit <NUM>.

With reference to <FIG>, an energy system <NUM>, <NUM>', <NUM>" according to embodiments of the present invention is schematically illustrated in block diagrams. The energy system is arranged to generate and to use thermal energy. The energy system <NUM> comprises a mechanical vapor recompression (MVR) unit <NUM>. The MVR-unit <NUM> comprises a primary heat exchanger <NUM> arranged to evaporate a working liquid provided to the primary heat exchanger <NUM>. The working liquid may be water provided to the primary heat exchanger <NUM> via a pipe <NUM> connected to an outer source of working liquid (not shown).

Preferably, the MVR-unit comprises a heating unit <NUM> arranged to heat the working liquid in the primary heat exchanger <NUM> to initiate the evaporation of the working liquid. After the working liquid has been provided to the primary heat exchanger <NUM>, the heating unit <NUM> is activated to heat the working liquid in the primary heat exchanger <NUM>. The heating unit <NUM> may be an electric heating unit. In the case of water as the working liquid, water is heated to approximately <NUM>-<NUM> by means of the heating unit <NUM> which is then turned off.

The MVR-unit comprises a compressor <NUM> arranged to compress vapor produced in the primary heat exchanger <NUM> and arranged to deliver the compressed vapor to the primary heat exchanger <NUM> to evaporate the working liquid in the primary heat exchanger <NUM>. Preferably, the compressor <NUM> is driven by a motor <NUM> which is started after the heating unit <NUM> has initially heated the working liquid in the primary heat exchanger <NUM>.

The MVR-unit <NUM> also comprises a primary vapor line <NUM> arranged in connection to the primary heat exchanger <NUM> and to the compressor <NUM> for transport of vapor produced in the primary heat exchanger <NUM> to the compressor <NUM>. Further, the MVR-unit <NUM> comprises a condenser <NUM> arranged to condense the compressed vapor to a condensed working liquid.

The condenser <NUM> is included in the primary heat exchanger <NUM>. Thus, one side or section of the primary heat exchanger <NUM> will then work as the condenser <NUM>, and another side or section of the primary heat exchanger <NUM> will work as an evaporator to evaporate the working liquid in the primary heat exchanger <NUM>. For example, the primary heat exchanger <NUM> may comprise a plurality of heat exchanging elements, such as lateral or longitudinal pipes, and the inside of the pipes may then work as the condenser <NUM>, and the outsides of the pipes may work as the evaporator, or opposite around; the outsides of the pipes may then work as the condenser <NUM>, and the inside of the pipes may work as the evaporator. This embodiment will be described in details in relation to <FIG>.

Thus, when the desired temperature is reached (for water, approximately <NUM>-<NUM>), the heating unit <NUM> is disengaged, and the compressor <NUM> is engaged. As the compressor <NUM> starts, it lowers the pressure in the inlet manifold to the compressor <NUM> to slightly under ambient pressure, which propagates to the primary heat exchanger <NUM> connected to the compressor <NUM> via the primary vapor line <NUM>, slightly lowering its pressure to slightly under ambient pressure. This pressure decrease enables the boiling of water (and subsequently production of steam) below <NUM>. As steam forms readily below <NUM>, it gets compressed by the compressor <NUM> and elevated, by the inserted pressure/volume work, to a temperature of approximately <NUM> with comparably little effort, in this described exemplary situation. The superheated steam is then lead to the primary heat exchanger <NUM> for evaporation of water in the primary heat exchanger.

An essential aspect of the embodiments of the energy system as defined by the appended claims, is that the MVR-unit <NUM> comprises at least one liquid line <NUM>, <NUM>', <NUM>" arranged in connection to the condenser <NUM> of the primary heat exchanger <NUM> for transport of the condensed working liquid, and for delivery of the thermal energy of the working liquid to external consumers, and back to the primary heat exchanger <NUM>, specifically back to the evaporator side or section of the primary heat exchanger <NUM>, for re-evaporation in the primary heat exchanger <NUM>. Preferably, the MVR-unit <NUM> comprises a pump <NUM> arranged on the liquid line <NUM>, <NUM>', <NUM>" to pump the working liquid via external thermal energy consumers to the primary heat exchanger <NUM>. According to the embodiments illustrated in the figures, the MVR-unit <NUM> comprises only one liquid line.

According to the embodiments illustrated in the figures the MVR-unit comprises a collection compartment <NUM> arranged in connection to the condenser <NUM> for collecting the condensed working liquid and vapors that have not been condensed. Thus, collecting of the condensed working liquid and vapor that has not been condensed is facilitated by the collection compartment <NUM>.

Further, according to the illustrated embodiments the liquid line <NUM>, <NUM>', <NUM>" is connected to the collection compartment <NUM>. However, as an alternative variation, the liquid line may be directly connected to the condenser <NUM> of the primary heat exchanger <NUM>.

Because the liquid line <NUM> in the embodiments illustrated in <FIG> is arranged in connection to the collection compartment <NUM> or possibly directly to the condenser <NUM> and to the primary heat exchanger <NUM> for transport of the condensed working liquid back to the primary heat exchanger <NUM> for re-evaporation in the primary heat exchanger <NUM>, the working liquid is arranged, according to the illustrated embodiments, to circulate in a closed loop. This enables a very efficient energy recuperation of the energy system <NUM>, which is beneficial for the external thermal energy outtake from the at least one liquid line.

As illustrated in <FIG>, the pipe <NUM> may be connected to the liquid line <NUM>, <NUM>', <NUM>". However, the pipe <NUM> may be directly connected to the primary heat exchanger <NUM>.

According to one embodiment, the energy system <NUM> also comprises at least one secondary heat exchanger <NUM> arranged for heat exchange between the working liquid flowing in the liquid line <NUM> and an external working fluid flowing in at least one external fluid line <NUM> to use thermal energy generated by the MVR-unit <NUM>. According to the embodiments illustrated in <FIG>, one secondary heat exchanger <NUM> and one external fluid line <NUM> is used. The external working fluid may be a liquid and/or a gas. Thus, for example, water and/or air can be used as the external working fluid.

Because the energy system <NUM>, according to the embodiments illustrated in <FIG>, comprises the secondary heat exchanger <NUM> arranged for heat exchange between the working liquid flowing in the liquid line <NUM> and an external working fluid flowing in an external fluid line <NUM> the thermal energy generated by the MVR-unit <NUM> will be used in an efficient way. Firstly, be transferring the thermal energy from the working liquid to the external working fluid, and secondly by using the external working fluid directly in an external system (not shown), such as an energy system or industrial system, and/or by heat exchanging the external working fluid with an additional working fluid of an external system.

According to the embodiment of the energy system <NUM> illustrated in <FIG>, the liquid line <NUM> and the secondary heat exchanger <NUM> of the energy system <NUM> are comprised by the MVR-unit <NUM>. Thus, the MVR-unit <NUM> may be provided to the intended location of use and then connected to an external system by the external liquid line <NUM> connected to the secondary heat exchanger <NUM>.

The energy system <NUM> may comprise at least one secondary vapor line <NUM>. According to the embodiments illustrated in <FIG>, the MVR-unit <NUM> comprises one secondary vapor line <NUM> arranged in connection to the condenser <NUM> and to the compressor <NUM> for transport of the compressed vapor from the condenser <NUM> to the compressor <NUM>. As discussed above, the MVR-unit <NUM> may be provided with a collection compartment <NUM> arranged in connection to the condenser <NUM> for collecting the condensed working liquid and vapors that have not been condensed. The secondary vapor line <NUM> is then connected to the collection compartment <NUM>. Thus, an energy system <NUM> is provided where the uncondensed compressed vapor can be used. The compressed vapor are then, which is advantageous, transported to a higher compression stage of the compressor <NUM> than the vapor transported through the primary vapor line <NUM>.

The MVR-unit <NUM> may comprise a separator <NUM> arranged in connection to the compressor <NUM> and arranged to separate droplets in the vapor transported to the compressor <NUM>. Preferably, the separator <NUM> is arranged on the primary vapor line <NUM> and on the secondary vapor line <NUM>.

The energy system <NUM> comprises a control system (not shown) arranged to monitor and to control the process of the MVR-unit and of the entire energy system regarding the pressure, temperature, flow ratio, compressor and pump performances together with other influential parameters of the system.

With reference to <FIG>, an energy system <NUM>' according to another embodiment, is schematically illustrated in a block diagram. The energy system <NUM>' is arranged to generate and to use thermal energy generated by a MVR-unit <NUM> in a similar way as the energy system <NUM> described in relation to <FIG>. The energy system <NUM>' has the same technical features and advantages as the corresponding features of the energy system <NUM> described above. Consequently, these technical features and advantages are not repeated or explained anew in order to avoid unnecessary repetition.

According to the embodiments illustrated in <FIG>, the secondary heat exchanger <NUM> of the energy system <NUM>' is arranged outside the MVR-unit <NUM>. Thus, the MVR-unit <NUM> may be provided to the intended location of use, where the secondary heat exchanger <NUM> and the external liquid line <NUM> have been prepared, and then may be connected to an external system by connection of the liquid line <NUM>' of the MVR-unit <NUM> to the secondary heat exchanger <NUM>.

<FIG> is a schematic illustration of the energy system <NUM>, <NUM>', <NUM>" illustrated in <FIG> according to some more specific embodiments. The MVR-unit <NUM> comprises a common pressure-tight enclosure <NUM> having a substantially circular cylindrical elongated shape along a longitudinal axis A. Many other shapes of the pressure-tight enclosure is naturally possible, e.g. enclosures having rectangular, elliptical, triangular, hexagonal, and other more complex cross-sectional shapes.

In <FIG>, a compact design of the MVR-unit <NUM> is illustrated. The compact design of the MVR-unit <NUM> is achieved, inter alia because the primary heat exchanger <NUM>, the compressor <NUM>, and the condenser <NUM>, which is a part of the primary heat exchanger <NUM>, are arranged within the common pressure-tight enclosure <NUM>.

The common pressure-tight enclosure <NUM> is provided with a first end <NUM>, and with a second end <NUM>, and wherein the secondary vapor line <NUM> is arranged at the first end <NUM> of the common pressure-tight enclosure <NUM> and the compressor <NUM> is arranged at the second end <NUM> of the common pressure-tight enclosure <NUM>. Preferably, the first end <NUM> and the second end <NUM> are opposite ends of the common pressure-tight enclosure <NUM> along the longitudinal axis A.

The primary heat exchanger <NUM> comprises a plurality of longitudinal pipes <NUM>. As illustrated in <FIG>, the longitudinal pipes <NUM> are arranged horizontally along the longitudinal axis A.

The compressed vapor from the compressor <NUM> are provided into the inside of each pipe of the plurality of longitudinal pipes <NUM> to evaporate the working liquid provided to the outside of each pipe of the plurality of longitudinal pipes <NUM>.

Thus, the superheated steam from the compressor <NUM> is provided through the inside of the horizontal set of pipes consisting of the plurality of the pipes <NUM>, e.g. longitudinal pipes, that are submerged in an operating medium, i.e. in the working liquid. The pipes <NUM> are submerged in a denser medium of lower temperature than the steam from the compressor <NUM>. The insides of the pipes <NUM> of the primary heat exchanger <NUM> work as the condenser <NUM> and the outsides of the pipes14 work as evaporator, and as disclosed above, the opposite, i.e. that the outsides of the pipes may then work as the condenser <NUM>, and the inside of the pipes may work as the evaporator.

In a further variation, the longitudinal pipes are not submerged into the working liquid. Instead, the working liquid is dispersed evenly onto the pipes e.g. sprayed onto via spraying nozzles. This is advantageous regarding the steam production flow rate.

In the embodiment illustrated in <FIG>, a secondary heat exchanger <NUM> is provided at the liquid line <NUM>, for heat exchanging thermal energy from the working liquid flowing in the liquid line to an external fluid line <NUM>. However, in another embodiment, similar to the embodiment illustrated in <FIG>, the secondary heat exchanger <NUM>, and the external fluid line <NUM>, are not included and the liquid line <NUM> is instead directly arranged to provide thermal energy from the working liquid to any outside consumer.

The present invention also relates to a method for using thermal energy generated by a mechanical vapor recompression (MVR) unit <NUM> of an energy system <NUM>, <NUM>', <NUM>". The energy systems have been described in detail above and it is herein referred to that description. The method will now be described with references to the flow diagram shown in <FIG>.

Thus, a method of an energy system is provided, where the energy system <NUM>, <NUM>', <NUM>" comprises a mechanical vapor recompression (MVR) unit <NUM>. The method comprises utilizing externally said energy system, thermal energy of a working liquid obtained during an MVR process performed by said MVR unit, preferably for heating processes, spaces or objects.

In the following, some embodiments of the method are listed. These have the same technical features and advantages as for the corresponding features of the energy systems <NUM>, <NUM>', <NUM>" described above. Consequently, these technical features and advantages are not repeated or explained anew in order to avoid unnecessary repetition.

The energy system <NUM>, <NUM>', <NUM>" comprises at least one liquid line <NUM>" where the working liquid flows, and the method comprises arranging the at least one liquid line in a configuration outside the energy system, preferably in a closed loop configuration, and providing it to energy consumers for any applicable use.

Claim 1:
An energy system (<NUM>, <NUM>', <NUM>") arranged to generate and to use thermal energy, the energy system (<NUM>, <NUM>', <NUM>") comprises a mechanical vapor recompression (MVR) unit (<NUM>), wherein thermal energy of a working liquid obtained during an MVR process performed by said MVR unit (<NUM>) is utilized externally said energy system (<NUM>, <NUM>', <NUM>"), preferably for heating processes, spaces or objects, wherein the MVR unit (<NUM>) comprises:
- a primary heat exchanger (<NUM>) arranged to receive:
- a working liquid and
- compressed vapor,
wherein the primary heat exchanger (<NUM>) is arranged to produce vapor by evaporation of the working liquid by heat exchanging the working liquid with the compressed vapor in the primary heat exchanger (<NUM>);
- a compressor (<NUM>) arranged to compress vapor produced in the primary heat exchanger (<NUM>) and arranged to deliver the compressed vapor to the primary heat exchanger (<NUM>) to evaporate the working liquid in the primary heat exchanger (<NUM>);
- at least one primary vapor line (<NUM>) arranged in connection to the primary heat exchanger (<NUM>) and to the compressor (<NUM>) for transport of vapor produced in the primary heat exchanger (<NUM>) to the compressor (<NUM>), and
wherein at least one liquid line (<NUM>, <NUM>', <NUM>") is arranged in connection to the condenser (<NUM>) of the primary heat exchanger (<NUM>) for transport of the condensed working liquid, and for delivery of the thermal energy of the working liquid to external consumers, and back to the primary heat exchanger (<NUM>), specifically back to an evaporator side or section of the primary heat exchanger (<NUM>), for re-evaporation in the primary heat exchanger (<NUM>).