FIELD OF THE INVENTION

This invention is an infrastructure (arrangement, architecture) and related methods for harvesting waste heat from industrial processes, storing and or processing this harvested thermal energy, distributing the stored and or processed thermal energy to point of use, optimizing the use of renewable energy and therefore provides solutions for balancing the power grid with this infrastructure.

STATE OF THE ART

[1] Power plants producing electricity have poor overall primary energy conversion efficiency. Depending on the type of power plant the primary energy consumed by the power plant, referenced as 100%, only results in 32% to 62% of useful electricity. There are two major places where power plants lose a lot of energy under the form of waste heat: the cooling tower that is used to condense the released steam from the driving turbine and the chimney that is used to evacuate the fume of burned fossil fuels in the boiler furnace. In most power plants around 30% of the primary energy will be dumped as waste heat through the cooling tower in the surrounding air and or in the surrounding waters. This is actual the latent heat that is contained in the released steam. As temperature levels of released steam typical are in the order of 35°C the dumped waste heat will be a few degrees lower than the temperature levels of the released steam. Older power plants also might dump around 30% or more, of the primary energy as waste heat contained in the fume of burned fossil fuels in the surrounding air through the chimney. Temperature levels of the fume vary very much on the type and age of the power plant. If one could harvest these waste heat sources and process them to useful thermal energy with a useful electricity consumption that is lower than the amount of useful thermal energy, the overall energy conversion efficiency of the power plant will be increased.

The useful thermal energy should be delivered at point of use and when needed thus here also considering storage and distribution losses of the useful thermal energy,

[2] Compressed air (CA) is another such process. Production of CA with compressors consumes a great share of total energy consumption in industry. For example, in Australia and European countries, energy consumption of CA systems, the vast majority being electricity, is about 10%, whilst in US, it is up to 30% of total industrial electricity consumption. Moreover, compressors have an extremely bad overall primary energy conversion efficiency. In general, a compression cycle only delivers about 10% useful CA power compared to the consumed primary energy, referenced as 100%. In general, 80% or more of the primary energy consumed is dumped into the surrounding environment as waste heat. Temperature levels of the dumped waste heat is around 70°C or above. If one could harvest these waste heat streams with a primary energy consumption that is lower than the amount of useful thermal energy, also considering storage and or processing and distribution losses of the useful thermal energy, the overall energy primary conversion efficiency of the compressor will be increased significant.

[3] As renewable electricity sources are developed more and more, it becomes increasingly challenging to match offer and demand on the electrical power grid. Also weather conditions may influence demand heavily over days or weeks. Several balancing solutions are in use like peak load shaving, virtual power plants, strategic reserves, grid level batteries, distributed batteries, etc. The problem these available solutions is that they are most often intrusive for the power consumers. If one could introduce permanent large electricity consumers in the grid that can be switched on/off for multiple days in the background without being noticed by the power consumers the use of renewable energy sources and the balancing of the power grid would be improved significant.

SUMMARY OF THE INVENTION

This invention provides an infrastructure (arrangement, architecture) and related methods for harvesting waste heat from industrial processes, storing and or processing this harvested thermal energy in over_the_seasons thermal batteries and/or over_the_day thermal buffers, distributing the stored and or processed thermal energy to point of use, optimizing the use of renewable energy and balancing the power grid with this infrastructure.

In a first aspect of the invention an arrangement for conversion of a non-fluid heat source into a fluid heat source, said arrangement comprising: means for providing fluid; means for conversion of said non-fluid heat source into said fluid heat source wherein said means exploits said fluid.

The above first aspect results in introducing one or more heat pump(s) in the vicinity of power plants, in particular connected to one or more heat exchanger(s), adapted to handle non-fluid heat sources resulting from such plants.

In a second aspect of the invention such arrangement is provided with a means for buffering the required fluids in a capacity covering the day-night dynamics.

In a third aspect of the invention such arrangement is provided with a means for buffering the required fluids in a capacity covering the over the season dynamics. In a fourth aspect of the invention a computer system, adapted for receiving one or more operational circumstances for such arrangement and capable of determining one or more control signals for said arrangement, is provided.

In a fifth aspect of the invention an energy architecture is provided, comprising: a power plant, providing electrical energy, and generating a fluid heat source; a heat network, an arrangement for conversion of said non-fluid heat source to harvested (waste-)heat, provided to said heat network.

The energy architecture above may exploit an arrangement for conversion of a non-fluid heat source into a fluid heat source, said arrangement comprising: means for providing fluid; means for conversion of said non-fluid heat source into said fluid heat source wherein said means exploits said fluid. The energy architecture above may comprise a means for buffering the required fluids in a capacity covering the so-called day-night dynamics and/or a means for buffering the required fluids in a capacity covering the so-called over the season dynamics.

The energy architecture above may include a computer system, adapted for receiving one or more operational circumstances for such arrangement or architecture and capable of determining one or more control signals for said arrangement or architecture.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 describes an arrangement for conversion of a (hot) (essentially) non-fluid (vapor, fume, steam) heat source into a fluid heat source.

Figure 2 describes the arrangement of Figure 1 with a heat pump.

Figure 3 illustrates the arrangement of Figure 1 and the electrical energy providing thereto.

Figure 4 provides an embodiment of the arrangement of Figure 1.

Figure 5 shows the arrangement of Figure 1 and its relation to a heat network (500).

Figure 6 shows the use of two different latent heat sources by the invented arrangement.

Figure 7 shows an energy architecture with a power plant and the arrangement of Figure 1.

Figure 8 provides an exemplary embodiment of the invention.

DESCRIPTION OF THE INVENTION

The invention is first described with drawings, then in more general terms and finally in a few exemplary embodiments. The drawings are used to clarify the connections between the various elements defining the arrangement or architecture without limiting the scope of the invention which is defined by the claims.

Figure 1 describes an arrangement (10) for conversion of a (hot) (essentially) non-fluid (vapor, fume, steam) heat source (100) into a fluid heat source (1 10), said arrangement (10) comprising: means (20) for providing fluid (120) with a guaranteed maximum temperature (T1 ); means (30) for conversion of said (hot) (essentially) non-fluid (vapor, fume, steam) heat source (100) into said fluid heat source (1 10), wherein said means (30) exploits said fluid (120).

Figure 2 describes the arrangement (10), wherein said means (20) has a so-called warm and cold side, and said means (20) and (30) being connected on the so-called cold side of means (20).

Figure 3 illustrates the arrangement (10), wherein said means (20) being connected to the electrical grid (300) and/or to renewable energy source (310) and/or a (rechargeable) electrical battery (320).

Figure 4 provides an arrangement (10) for conversion of a (hot) (essentially) non-fluid (vapor, fume, steam) heat source (100) into a fluid heat source (1 10), said arrangement (10) comprising: means (20) for providing fluid (120) with a guaranteed maximum temperature (T1 ); means (30) for conversion of said (hot) (essentially) non-fluid (vapor, fume, steam) heat source (100) into said fluid heat source (1 10), wherein said means (30) exploits said fluid (120) indirectly.

Figure 5 shows the arrangement (10), further being provided for being connected to (and providing heat thereto) a heat network (500).

Figure 6 shows the use of these two different latent heat sources (100) (steam) and (200) (fume), a separate means for conversion (230), a separate (in terms of temperature or routing) fluid (220), generated by means (20), and a different resulting (third fluid) compared to second fluid (1 10).

Figure 7 shows an energy architecture comprising: a power plant (700), providing electrical energy, and generating a (hot) (essentially) non-fluid (vapor, fume, steam) heat source (100); a heat network (500) (and a cold network (530)); an arrangement (10) for conversion of said (hot) (essentially) nonfluid (vapor, fume, steam) heat source (100) (via a fluid heat source (1 10), up converted (in terms of temperature)) to harvested (waste-)heat (130), provided to said heat network (500), with the embodiment wherein a (isolated) means for fluid storage (500) being designed for having an seasonal capacity, hence being designed for having at least a 2 months, preferably 3 months (but less than 12 months, preferably 6 months), provided in between arrangement (10) and said heat network (500). The alternative with a similar (isolated) means for fluid storage (500) in between the connection to the cold network (530) is also possible or a combination thereof. In the invention the (hot) (essentially) non-fluid (vapor, fume, steam) heat source (100) (receivable from a power plant (700) (Figure 5)) can be the released steam in the cooling tower of a power plant. The means (20) for providing fluid (120) with a guaranteed maximum temperature (T1 ) provides a first fluid (120) with a temperature lower than the temperature of the released steam. The means (30) for conversion of said (hot) (essentially) non-fluid (vapor, fume, steam) heat source (100) into said fluid heat source (1 10) will result in said first fluid to be heated up close to but lower than temperature of the released steam, resulting in a second fluid (1 10).

In a further realization of the above, said second fluid is used in one or more heat pumps, such a NH3 heat pump, or more generally speaking said fluid heat source (1 10) can be and is preferably exploited by said means (20), in particular to provide said first fluid (120).

As the temperature of the released steam can be variable, as it is determined by the operation of the respective power plant, the temperature of the first fluid (120) may be made variable also, to optimize the overall operation of the arrangements described. A particular way of providing such variability is to provide bypass circuits.

In a further realization of the above the harvesting (waste-) heat (130) from said (hot) (essentially) non-fluid (vapor, fume, steam) heat source (100), whereby said harvest (waste-)heat (130) being the outcome at the hot side of said means (20), is realized by injecting this into thermal networks for district heating.

In an alternative, the arrangement is provided with a (thermal battery) means for fluid storage (510), connected thereto, in particular to the outcome at the hot side of said means (20), preferably said means for fluid storage (500) is being designed for having an seasonal capacity, said (thermal battery) means for fluid storage (510) is then further connected to thermal networks for district heating.

The means (20) may be connected to the generator of the power plant, which latent heat it is harvesting. Alternatively the means (20) may also be connected to the electrical grid (300) and/or to renewable energy source (310) and/or a (rechargeable) electrical battery (320).

In another realization the hot (essentially) non-fluid (vapor, fume, steam) heat source (100) (receivable from a power plant (700) (Figure 5)) is the heat in the chimney of a power plant. The means (20) for providing fluid (120) provides a first fluid (120) The means (30) for conversion of said (hot) (essentially) non-fluid (vapor, fume, steam) heat source (100) into said fluid heat source (1 10) will result in said first fluid to be heated up, resulting in a third fluid (1 10).

The above steam and fume realizations, which have in essence the same layout can be and preferably are combined, be it that the used fluids to the respective cooling tower and chimney and the resulting heated fluids may be routed differently during this combined arrangement towards either the heat network, heat buffers and/or heat batteries. Figure 6 illustrates the use of these two different latent heat sources (100) (steam) and (200) (fume), a separate means for conversion (230), a separate (in terms of temperature or routing) fluid (220), generated by means (20), and a different resulting (third fluid) compared to second fluid (1 10). The different routing thereof is also schematically indicated.

As the means (20) requires electrical energy, in case balancing the power grid is required, providing thermal buffers to ensure continued operation of the arrangement is the means (20) are powered down and/or operating temporality not at the required operating point, the arrangement further comprises a means (400) for buffering the fluid (160) provided by said means (20) (at its cold side). As mentioned above for the steam part and the fume part one may decide to both use a buffer or only for one of those for the fluid (120), (220) to be provided. Similarly as shown in Figure 520 one may also put a buffer for the fluid (120) (and also (220)) and also here one may to decide to use such buffer for both or only one of those.

In view of the above indicated variabilities (of the temperature of the released steam and/or fume temperature) on the heat source(s) side and/or (optimally) available electrical energy, preferably one provides for a computer system, adapted for receiving one or more such operational circumstances for said arrangement (10) or (600) and capable of determining one or more control signals for said arrangement (10) or (600), like steering the provided bypass circuits and/or powering of the means (20).

In essence the above insights results in use of an arrangement (10) or (600) in the power plant energy conversion cycle, in particular (a) use of heat pumps in combination with a power plant; and/or (b) the use of means for temporal (seasonal) fluid storage (500), and especially in a preferred embodiment said arrangement (10) or (600) further includes means for temporal (over the day) buffering (400).

For completeness, it is worth noting that the one or more heat pumps are not necessarily of the same type or operated at the same operating point. While the above has been explained from the perspective of providing hot fluid to a heating network or grid, also the alternative of using cold fluid generated in the arrangements in a separate cooling network or grid, or a combination of those, is also possible. In the above description bypassing thermal buffers and/or batteries was mentioned. A further degree of freedom can be provided by providing bypasses over the heat exchangers.

A few exemplary embodiments are now described.

In a first embodiment of this invention following Figure 8, the latent heat extracted frim/while condensing released steam in the cooling towers from power plants is not dumped into the environment. Depending on the type of power plant the released steam in the cooling towers will be somewhere around 35°C. Cold fluid of order 10°C, or any other applicable temperature level, lower than the temperature of the released steam will be used in one or more heat exchanger circuits to condense the released steam back into its liquid state. As a result, the cold fluid will heat up to just a few degrees below the release temperature of the steam, so order 30°C. The first novelty is to introduce a one or more heat pumps (1 101 ), and or one or more over_the_seasons thermal heat batteries (1 102), in the power plant energy conversion cycle. Appropriate type of heat pumps are, for example but not limitative, NH3 heat pumps. At their cold side they can work with incoming fluid at 30°C and outgoing fluid at 10°C. So this side, optional with some bypass circuits to optimize temperature levels, is very suitable to condense the steam and harvest the latent heat. At their hot side they can work with incoming fluid at 40°C and outgoing fluid at 80°C. The COP of an NH3 heat pump in this temperature working regime can be up to 4.5 or more. These hot side temperature levels are ideal to be injected into thermal networks for district heating (1 103), or other kind of use. Unfortunately, the production profile, which is often all year and day round, does not match the use profile that is season related. It is possible to store the heat contained in the outgoing fluid in large over_the_seasons thermal heat batteries. Most appropriate technology both technical and economical or so called larges sized stratified water buffers but any other type of thermal buffer can be used. The temperature delta in this over_the_seasons thermal heat batteries will thus be around 80°C down to around 40°C. These temperature levels and temperature delta remain ideal for district heating networks for comfort heating and or sanitary hot water and or other processes that require these kind of temperature levels and deltas. So it is now possible to harvest latent heat contained in released steam from power plants all year round, process it to useful temperature levels and deltas, store it over_the_seasons thermal heat batteries and finally distribute it as useful thermal energy though thermal distribution networks at periods that it is required. Considering any type of power plant of which 30% of the primary energy is harvested with an electric heat pump with a COP of 4.5, this means 6.6% of the useful electricity output of the power plant will be consumed. This consumption is on-site of the power plant of the heat pumps can be installed onsite thus offloading transmission and or distribution grids. The over_the_seasons thermal heat battery can be offsite and or distributed alongside the thermal network. Considering thermal storage losses and thermal distribution losses of together 20% of the harvested useful thermal energy we end up with 24% of useful thermal energy at point of use. So the overall primary energy conversion efficiency of the power plant is boosted with 17.4% of useful thermal heat delivered at point of use when needed.

In a second embodiment of this invention, the heat in the chimney of the power plant (1 104), is harvested very much alike said first embodiment. On top this infrastructure and method additional may harvest latent heat from the condensing water vapor in the fume. Anyhow, depending on the type and age of the power plant, the overall primary energy conversion efficiency of the power plant is boosted with 5% to 30% of useful thermal heat delivered at point use when needed.

In a third embodiment of this invention one, one combined or two or more over_the_days thermal buffers (1 105), are introduced at the cold side of the heat pumps as said in embodiment one and or embodiment two. The difference between the thermal batteries as said in embodiment one &two and thermal buffer as said in this embodiment is that in the buffer there is no significant temperature delta require. In a buffer we can suppose the temperature of the fluid to be more or less equal everywhere. These buffers can be totally or partially filled up with cold fluid coming from the cold side of the heat pumps and can be empty or partially filled up with warmed up fluid coming from the heat exchangers that condenses the released steam and or chills the fumes in the chimney of the power plant. In case there is a need for balancing the power grid, the heat pumps can be switched off totally and or partially and the thermal buffers can be used to continue condensing the released steam and or chilling the fumes as said in embodiment one and embodiment two. In this use case it is required to install more heat pump capacity compared to the maximum generation capacity of the heat pump.

In a fourth embodiment of this invention, considering seasonal conditions and needs, one or more of the heat exchanger circuits as said in embodiment one to embodiment three can be bypassed and or the operating set points of the heat pumps can be adjusted such that COPs of the heat pumps are optimized and or temperature levels and or temperature delta in the over_the_seasons thermal heat batteries are minimized thus minimizing thermal storage losses and thermal distribution losses.

In a fifth embodiment of this invention, the over_the_seasons thermal heat buffer is equipped with at least two or more heat exchanger circuits from at least one heat pump that is only or mainly processing heat in the over_the_seasons thermal heat buffer itself. These heat pumps can independently being be used for balancing the power grid and or for optimized use of renewable energy sources. If the COP of these heat pumps is higher than the heat pumps in said embodiment one to five, the overall energy efficiency of the entire infrastructure is improved. Depending on the temperature working point of these heat pumps it is possible the will produce cold at their cold site that is no longer suitable for district heating. In such case those levels could be used for cooling purposes through thermal cooling grids or combined heating & cooling grids. Another configuration of this embodiment is the use of at least one over_the_seasons thermal heat buffer and at least one over_the_days thermal cold buffer with in between at least one heat pumps. A power plant equipped with one or more heat pumps, one or more released_vapor_to_chilled_fluid heat exchanger circuits at the cold side of the heat pumps, and one or more over_the_seasons thermal heat batteries at the hot side of the heat pumps. The above exemplary embodiment can be summarized in that the invention provides as such

1 . A power plant equipped with one or more heat pumps, one or more fume_to_chilled_fluid heat exchanger circuits at the cold side of the heat pumps, and one or more over_the_seasons thermal heat batteries at the hot side of the heat pumps.

2. A power plant as described above equipped with one or more over_the_days thermal buffers on the cold side of the heat pumps.

3. A power plant as described above with adjustable operating points of the heat pumps and adjustable temperature levels and or adjustable temperature delta in the over_the_seasons thermal heat batteries and or various bypasses to optimize the harvested waste heat.

4. The providing of at least one over the_seasons_thermal buffer with at least one heat pump that is operated as part of power grid balancing infrastructure and or as part of renewable energy optimization infrastructure.