heat pump

Abstract

Heat pump for absorbing an exhaust steam stream and generating a process steam stream in use, wherein the heat pump, arranged in series in a closed circuit, comprises the following: an exhaust condenser; a compressor fluidically connected to the exhaust condenser; a process steam generator fluidically connected to the compressor; an expansion valve fluidically connected to the process steam generator, wherein the evaporation condenser is fluidically connected to the expansion valve; so that a refrigerant can circulate in the closed circuit during use; wherein the compressor is configured to increase the pressure of the refrigerant in order to increase the temperature of the refrigerant during use; wherein the expansion valve is configured to reduce the pressure of the coolant in order to reduce the temperature of the coolant in use; wherein the exhaust condenser is configured to receive an exhaust evaporation stream and transfer heat from the exhaust evaporation stream to the coolant in use; and the process steam generator is configured to take in water and transfer heat from the coolant to the water to generate a process steam stream in use.

Description

TECHNICAL FIELD

[0001] The present invention relates to heat pumps. In particular, the present invention relates to heat pumps for absorbing exhaust steam. STATE OF THE ART

[0002] State-of-the-art closed-loop heat pumps circulate a coolant in a closed loop to transfer heat from a heat source to a heat sink. The heat source may be a waste stream in an industrial process, and the heat sink may be a process stream within the industrial process. The heat pump is therefore used to extract heat from the waste stream of the industrial process and transfer the heat to a process stream within the industrial process.

[0003] In the following description, the terms "exhaust steam" and "process steam" are used. These terms will first be clarified. Exhaust steam typically refers to steam that has been used in an industrial or commercial process and therefore has a lower exergy level. In many industrial processes, steam is used for tasks such as heating, sterilizing, or mechanical work. After performing its intended function, the steam can become exhaust steam, having transferred its thermal energy to the process.

[0004] Exhaust steam is typically at a low temperature level (between 50 degrees Celsius and 110 degrees Celsius). Exhaust steam has a lower exergy than process steam. In some examples, the exhaust steam may be low-pressure or vacuum steam, which can be used for minor, specific processes, such as preheating, instead of the main industrial process.

[0005] Exhaust steam may still contain some residual heat, and efforts are often made to recover and reuse this heat energy instead of dissipating it into the environment. This process is known as steam condensate recovery. By capturing and utilizing exhaust steam heat, industrial companies can improve energy efficiency and reduce overall energy consumption.

[0006] In summary, waste steam is steam that, due to its low temperature, is difficult to use in an industrial process. The waste steam may have been used in an industrial process and released a significant amount of exergy; in such cases, it is often considered a by-product.

[0007] Due to its low temperature level, exhaust steam can either be used for further processing or can only be used to preheat processes. Typically, exhaust steam is condensed at the end of the process using a cooling tower so that the exhaust steam can be safely vented into the atmosphere. Typically, the energy in the exhaust steam is not usefully captured.

[0008] Efforts to recover and reuse heat from exhaust steam are part of sustainable and energy-efficient practices in various industries.

[0009] Exhaust steam can also be referred to as spent steam or used steam. The exhaust steam does not always have to be contaminated steam. It will be obvious to those skilled in the art that the invention described below is particularly advantageous when the steam is contaminated, but the invention described below works equally well with completely uncontaminated or minimally contaminated exhaust steam.

[0010] Process steam refers to steam generated and used specifically in industrial processes. Many industrial companies use steam as a heat transfer medium or for various applications such as heating, sterilizing, drying, and mechanical work. The term process steam distinguishes steam used in these industrial processes from other types of steam applications, such as power generation or space heating.

[0011] In industrial environments, boilers are typically used to generate process steam by heating water to its boiling point. The resulting steam is then transported to various parts of the facility to perform specific tasks within the manufacturing or production processes. The properties of the process steam, such as pressure and temperature, are often customized to meet the requirements of the specific industrial application.

[0012] Process steam is a critical component in industries such as chemical processing, food and beverage production, pharmaceuticals, pulp and paper manufacturing, and many others. The efficient generation and use of process steam are key aspects for optimizing industrial operations and ensuring the overall productivity of various manufacturing processes.

[0013] Process steam can also be referred to as pure steam or uncontaminated steam. Those skilled in the art will understand that process steam may still contain some minor pollutants or impurities. In this respect, process steam does not have to be 100% pure steam, completely free of any pollutants or impurities. Process steam typically has a higher temperature than exhaust steam and is adjusted to the temperature required in the industrial process.

[0014] Mechanical vapor recompression (MVR) is a well-known method for increasing energy efficiency and recycling heat in steam-based heat distribution systems in industrial processes such as manufacturing plants. MVR works by extracting exhaust steam and passing it through an MVR device, which typically includes a centrifugal compressor or a reciprocating compressor designed specifically for this purpose and for steam (i.e., not a refrigeration compressor). MVR increases the temperature and vapor pressure as the steam flows through the MVR system. In principle, this is classified as an "open-loop heat pump" system, meaning that the process fluid (steam) also acts as the working fluid within the heat pump / MVR.

[0015] This type of configuration theoretically offers the highest possible efficiency (it requires no heat exchangers or phase changes; it acts directly on the exhaust steam). Because MVR works directly with the exhaust steam, the MVR inlet steam is also the MVR outlet steam. Those skilled in the art will know that this means that a contaminated inlet steam stream results in a contaminated outlet steam stream.

[0016] Contaminated steam in industrial processes can lead to various problems and complications. Contaminants in steam can negatively impact the equipment used in the process and the final product. Contaminants in steam, such as foreign matter or solid particles, can cause damage to MVR compressor components. These particles can erode or corrode components, reducing the efficiency and service life of the equipment. This can lead to increased energy consumption and reduced overall system performance. In industrial operations where steam comes into direct contact with products (such as food, chemical, and pharmaceutical manufacturing), contaminants in steam can lead to product contamination. This can cause quality issues, compliance concerns, and even health and safety risks.Contaminated steam can also pose safety hazards, especially if the contaminants are corrosive or toxic. This poses risks to both the equipment and personnel working in the industrial facility. Dealing with the consequences of contaminated steam, such as equipment damage to MVR compressor components, increases the required maintenance to an unreasonable level.

[0017] As a result, MVR can either not be used at all because the steam is too contaminated, or the process requires an unacceptable level of maintenance. Excessive maintenance has clear implications for the cost-effectiveness of operating the system and downtime.

[0018] In many manufacturing plants, process steam is typically generated by a conventional boiler system, e.g., using natural gas or oil, and then the steam is distributed to various heat sinks / consumers within the respective plant. At the "end of the line," the temperature of the remaining steam is so low or even condensed that the steam cannot be used further, and this is where a heat pump can be used to recycle some of the waste heat. However, in some manufacturing plants, steam is only used indirectly, for example, to evaporate moisture from various products, such as the moisture in food. In some cases, the evaporated moisture then mixes with surrounding air, and the air then becomes saturated with water, either in vapor or aerosol form.In other cases, there is no air in the system, and the evaporated moisture could be considered more or less pure steam, apart from some impurities in some cases. Typically, this steam is at a low pressure, either as vacuum steam or atmospheric, in the case where it is mixed with air, and in principle, it could also come out as superatmospheric if the system is set up to maintain pressure. In the systems described, exhaust steam is generated indirectly, as a result of using the source steam (or another heat source) to remove steam from a product or raw material. Some examples of industrial processes that might generate such exhaust steam are food production in general, pulp and paper and animal feed production, certain chemical processes, carbon capture and storage, direct air capture, and more.In general, this applies to processes that use evaporation columns.

[0019] One of the main problems to be solved is to extract useful heat from exhaust steam when the exhaust steam has a low exergy and may be contaminated.

[0020] A major obstacle to implementing a system to usefully extract heat from exhaust steam is the slow development of heat pumps capable of handling heat sources above 50 degrees Celsius. For example, there has been a slow development of heat pumps capable of handling heat sources between 50 degrees Celsius and 110 degrees Celsius, between 50 degrees Celsius and 120 degrees Celsius, and between 50 degrees Celsius and 130 degrees Celsius.

[0021] Water is used as a heat transfer fluid in district heating systems. District heating systems use a centralized energy distribution system that provides heating (and sometimes cooling) to multiple buildings or residential areas from a common heat source.

[0022] The invention is based on the object of eliminating or reducing at least one of the disadvantages of the prior art or at least providing a useful alternative to the prior art.

[0023] The object is achieved by features specified in the following description and in the following claims. SUMMARY

[0024] According to the first aspect of the invention, a heat pump is provided for receiving an exhaust steam stream and generating a process steam stream in use, the heat pump comprising, arranged in series in a closed circuit, an exhaust steam condenser; a compressor fluidically connected to the exhaust steam condenser; a process steam generator fluidly connected to the compressor; an expansion valve fluidly connected to the process steam generator, the exhaust steam condenser being fluidly connected to the expansion valve; such that, in use, a coolant can circulate in the closed circuit; wherein the compressor is configured to increase the pressure of the coolant to increase the temperature of the coolant in use; wherein the expansion valve is configured to decrease the pressure of the coolant to decrease the temperature of the coolant in use.wherein the exhaust steam condenser is configured to receive an exhaust steam stream and transfer heat from the exhaust steam stream to the coolant in use; and wherein the process steam generator is configured to receive water and transfer heat from the coolant to the water to generate an in-use process steam stream.

[0025] Advantageously, the heat pump can provide a useful compromise between MVR process and intermediate-loop systems. In intermediate-loop systems, heat is recovered from a low-temperature water loop (typically a cooling tower loop with temperatures between 20-35 degrees Celsius). Intermediate-loop systems also ensure the separation of the working fluid and process fluid, but due to the lower heat source temperature, the efficiency (coefficient of performance) is lower. An MVR exhibits the highest efficiency but cannot be operated under all conditions or only with increased maintenance effort. Advantageously, the heat source and heat sink remain separate. Advantageously, mass and energy balances can be different.

[0026] Advantageously, different qualities of steam streams (i.e. exhaust steam and process steam) are not mixed.

[0027] Although MVR is more compact than a comparable closed-loop heat pump, as no heat exchanger piping, etc., is required, the compressor itself, especially in vacuum applications, is advantageously much larger than the heat exchangers required in the described closed-loop heat pump. Therefore, integration into existing systems using the system described here may be easier than integrating an MVR system.

[0028] In MVR systems, the steam compression always produces superheated steam. If the application requires saturated steam, water must be injected, which increases the complexity of the system. Advantageously, however, the closed-loop heat pump in the system described herein produces saturated or superheated steam without additional water injection.

[0029] The described closed-loop heat pump can be particularly advantageous in vacuum steam applications. Low pressure conditions require very high compression ratios. The pressure ratio with a closed-loop heat pump can be selected based on the choice of working fluid. Low pressure conditions also mean high specific volumes, which can lead to very high flow rates for the MVR.

[0030] MVR is always a compromise between power output and temperature increase. Typical temperature increases per stage are limited to 7-10 K in vacuum steam applications. Closed-loop heat pumps require only a large heat exchanger on the heat source side, and the mass flow rate is independent of the process fluid pressure. Temperature increases of up to 70 K per stage are possible in some examples.

[0031] Because MVR uses the process fluid as the working fluid, the MVR compressor must deal with residues directly, which can be difficult or even impossible depending on the contamination. The compressor of closed-loop heat pumps is always shielded from the process steam. The compressor only comes into contact with the internal working fluid.

[0032] Most state-of-the-art MVR compressors use oil as a lubricant. It can be very difficult to ensure zero contamination of the process steam (e.g., for pure steam applications in the pharmaceutical, food, or chemical industries).

[0033] The heat pump can be a high-temperature heat pump.

[0034] The heat pump can comprise one or more receivers.

[0035] The heat pump may include instrumentation.

[0036] The heat pump may include one or more oil separators. The heat pump may include one or more valves.

[0037] The heat pump can include one or more buffer tanks.

[0038] The heat pump may include one internal heat exchanger or several internal heat exchangers.

[0039] The heat pump may further comprise a pressurizing device configured to pressurize water provided to the process steam generator such that the water provided to the process steam generator is maintained in the liquid phase until the water reaches the process steam generator in use.

[0040] According to a second aspect of the invention, there is provided a heat pump system for receiving an exhaust steam stream and generating a process steam stream in use, the heat pump system comprising: a heat pump according to the first aspect of the invention; a coolant provided in the closed circuit; an exhaust steam stream provided to the exhaust steam condenser; and a water stream provided to the process steam generator.

[0041] According to a third aspect of the invention, a heat pump is provided for receiving an exhaust steam stream and heating a process fluid stream in use, the heat pump comprising, arranged in series in a closed circuit, an exhaust steam condenser; a compressor fluidically connected to the exhaust steam condenser; a process fluid heat exchanger fluidly connected to the compressor; an expansion valve fluidly connected to the process fluid heat exchanger, the exhaust steam condenser being fluidly connected to the expansion valve; such that, in use, a coolant can circulate in the closed circuit; the compressor being configured to increase the pressure of the coolant to increase the temperature of the coolant in use; the expansion valve being configured to decrease the pressure of the coolant to decrease the temperature of the coolant in use.wherein the exhaust steam condenser is configured to receive an exhaust steam stream and transfer heat from the exhaust steam stream to the coolant in use; and wherein the process fluid heat exchanger is configured to pass a process fluid stream through;

[0042] Transferring heat from the coolant to heat the process fluid stream in use.

[0043] The process fluid heat exchanger may be configured to heat a process fluid stream comprising water.

[0044] The process fluid heat exchanger may be configured to heat a process fluid stream comprising thermal oil or condensate from an industrial process.

[0045] The heat pump can be a high-temperature heat pump.

[0046] The heat pump can comprise one or more receivers.

[0047] The heat pump may include instrumentation.

[0048] The heat pump may include one or more oil separators. The heat pump may include one or more valves.

[0049] The heat pump can include one or more buffer tanks.

[0050] The heat pump may include one internal heat exchanger or several internal heat exchangers.

[0051] The heat pump may further comprise a pressurizing device configured to pressurize the process fluid stream to maintain the process fluid stream in the liquid phase during use.

[0052] According to a fourth aspect of the invention, there is provided a heat pump system for receiving an exhaust steam stream and heating a process fluid stream in use, the heat pump system comprising: a heat pump according to the third aspect of the invention; a coolant provided in the closed circuit; an exhaust steam stream provided to the exhaust steam condenser; and a process fluid stream provided to the process fluid heat exchanger.

[0053] According to a fifth aspect of the invention, there is provided a method of operating a steam-to-steam heat pump, the method comprising the steps of: providing a heat pump system according to the second aspect of the invention; and operating the heat pump to generate a process steam stream.

[0054] The step of operating the heat pump may comprise circulating a coolant in the closed circuit.

[0055] The step of operating the heat pump may further comprise: transferring heat from the exhaust steam stream to the coolant using the exhaust steam condenser; increasing the pressure of the coolant using the compressor, thereby increasing the temperature of the coolant; and transferring heat from the coolant to the water to generate process steam.

[0056] The step of operating the heat pump may further comprise reducing the pressure of the coolant to reduce the temperature of the coolant.

[0057] According to a sixth aspect of the invention, there is provided a method of operating a vapor-liquid heat pump, the method comprising the steps of: providing a heat pump system according to the fourth aspect of the invention; and operating the heat pump to heat the process fluid stream.

[0058] The step of operating the heat pump may comprise circulating a coolant in the closed circuit.

[0059] The step of operating the heat pump may further comprise: transferring heat from the exhaust steam stream to the coolant using the exhaust steam condenser; increasing the pressure of the coolant using the compressor, thereby increasing the temperature of the coolant; and transferring heat from the coolant to the process fluid stream.

[0060] The step of operating the heat pump may further comprise reducing the pressure of the coolant to reduce the temperature of the coolant.

[0061] The step of operating the heat pump may further comprise pressurizing the process fluid stream to maintain the process fluid stream in the liquid phase. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 shows a prior art mechanical vapor recompression system; Fig. Figure 2 shows an example of a closed-cycle steam-to-steam heat pump according to the first aspect of the invention; and Fig. 3 shows an example of a closed-cycle vapor-liquid heat pump according to the second aspect of the invention.

[0062] For clarity, some elements in some of the figures may be omitted from reference numerals. Those skilled in the art will understand that the figures are only schematic drawings. The relative proportions of individual elements may also be distorted. DETAILED DESCRIPTION OF THE DRAWINGS

[0063] Fig. Figure 1 shows a prior art mechanical vapor recompression (MVR) system 100. The MVR system includes an open-cycle heat pump 110 in the form of a compressor configured to receive exhaust steam at a heat sink 120 and discharge superheated steam at a heat sink 130.

[0064] Fig. Figure 2 shows a heat pump 200 for receiving an exhaust steam stream 201 and generating a process steam stream 202 in use, as will now be explained.

[0065] The heat pump 200 comprises a closed circuit 203. Within the closed circuit 203, arranged in series, is an exhaust steam condenser 204, which is fluidly connected to a compressor 205, which is fluidly connected to a process steam generator 206, which is fluidly connected to an expansion valve 207, which is fluidly connected to the exhaust steam condenser 204. In use, a coolant (not shown) can circulate within the closed circuit 203.

[0066] The compressor 205 is configured to increase the pressure of the refrigerant to increase the temperature of the refrigerant in use. The expansion valve 207 is configured to decrease the pressure of the refrigerant to decrease the temperature of the refrigerant in use. The exhaust steam condenser 204 is configured to receive the exhaust steam stream 201 and transfer heat from the exhaust steam stream 201 to the refrigerant in use. The process steam generator 206 is configured to receive water 208 and transfer heat from the refrigerant to the water 208 to generate the process steam stream 202 in use. With further reference to Fig. 2, the exhaust steam stream 201 is supplied to the exhaust steam condenser 204 by a first pump 209. Those skilled in the art will understand that the first pump 209 shown is not necessary and that the exhaust steam stream 201 can be supplied to the exhaust steam condenser 204 in a myriad of different ways, such as, but not limited to, providing an aspirator to draw the exhaust steam stream 201 to the exhaust steam condenser 204. After the exhaust steam stream 201 is passed through the exhaust steam condenser 204, a stream of exhaust steam condensate 210 is supplied from the exhaust steam condenser 204. The water 208 is supplied to the process steam generator 206 by a second pump 211.

[0067] Those skilled in the art will understand that the second pump 211 shown is not necessary and that the water 208 can be supplied to the process steam generator 206 in countless different ways.

[0068] The heat pump 200 may, in some examples, be a high-temperature heat pump. The heat pump 200 simultaneously acts as a steam condenser at one end (i.e., on the exhaust steam side) and a steam generator at another end (i.e., on the process steam side), eliminating the need for an intermediate heat exchange process that is not between the internal process of the heat pump 200 and the external steam source / sink. The heat pump 200 may include additional components not described herein for brevity and clarity. Non-limiting examples of such additional components include, for example, receiver and / or instrumentation(s) and / or oil separator(s) and / or valve(s) and / or buffer tank(s) and / or internal heat exchangers, such as, but not limited to, recuperator(s).

[0069] In some examples, the heat pump 200 may further include a pressurizing device (not shown) configured to pressurize the water provided to the process steam generator such that the water provided to the process steam generator is maintained in the liquid phase until the water reaches the process steam generator in use.

[0070] Fig. Figure 3 shows a heat pump 200' for receiving an exhaust steam stream 201' and heating a process fluid stream 208' in use, as will now be explained. The process fluid stream 208' in the presently described example is water. In some examples, the process fluid stream 208' is thermal oil. In some examples, the process fluid stream 208' is condensate from the industrial process in which the heat pump 200' is installed.

[0071] Similar to the heat pump 200, which with reference to Fig. 2, the heat pump 200' comprises a closed circuit 203'. Within the closed circuit 203', arranged in series, is an exhaust steam condenser 204', which is fluidly connected to a compressor 205', which is fluidly connected to a process fluid heat exchanger 206', which is fluidly connected to an expansion valve 207', which is fluidly connected to the exhaust steam condenser 204'. In use, a coolant (not shown) can circulate within the closed circuit 203'.

[0072] The compressor 205' is configured to increase the pressure of the refrigerant to increase the temperature of the refrigerant in use. The expansion valve 207' is configured to decrease the pressure of the refrigerant to decrease the temperature of the refrigerant in use. The exhaust steam condenser 204' is configured to receive the exhaust steam stream 201' and transfer heat from the exhaust steam stream 201' to the refrigerant in use. The process fluid heat exchanger 206' is configured to receive the process fluid stream 208', which is water in the presently described example, and transfer heat from the refrigerant to the process fluid stream 208' to produce a heated process fluid stream 202' in use.

[0073] With further reference to Fig.3, the exhaust steam stream 201' is supplied to the exhaust steam condenser 204' by a first pump 209'. Those skilled in the art will understand that the first pump 209' shown is not necessary and that the exhaust steam stream 201' can be supplied to the exhaust steam condenser 204' in a myriad of different ways, such as, but not limited to, providing an aspirator to draw the exhaust steam stream 201' to the exhaust steam condenser 204'. After the exhaust steam stream 201' has been passed through the exhaust steam condenser 204', a stream of exhaust steam condensate 210' is supplied from the exhaust steam condenser 204'. The process fluid stream 208', i.e., water in the presently described example, is supplied to the process fluid heat exchanger 206' by a second pump 211'.

[0074] Those skilled in the art will understand that the second pump 211' shown is not necessary and that the process fluid 208' can be supplied to the process fluid heat exchanger 206' in countless different ways.

[0075] The heat pump 200' may, in some examples, be a high-temperature heat pump. The heat pump 200' simultaneously acts as a steam condenser at one end (i.e., on the exhaust steam side) and a process fluid heater at another end (i.e., on the process fluid side), eliminating the need for an intermediate heat exchange process that is not between the internal process of the heat pump 200' and the external steam source / sink. The heat pump 200' may include additional components not described herein for brevity and clarity. Non-limiting examples of such additional components include, for example, receiver and / or instrumentation(s) and / or oil separator(s) and / or valve(s) and / or buffer tank(s) and / or internal heat exchangers, such as, but not limited to, recuperator(s).

[0076] In the example described herein, the process fluid stream 208' is water, therefore the heated process fluid stream 202' is heated water. The term "heated water" is intended to mean water at a temperature higher than the temperature of the water supplied to the process fluid heat exchanger 206'.

[0077] It will be understood that in an alternative example in which the process fluid stream 202' is heated, the process fluid heat exchanger then the heated process fluid stream 202' is heated thermal oil. The term "heated thermal oil" shall mean thermal oil at a temperature higher than the temperature of the thermal oil supplied to the process fluid heat exchanger 206'.

[0078] It should be understood that in an alternative example where the process fluid stream 208' is condensate from the industrial process, the heated process fluid stream 202' is heated condensate. The term "heated condensate" is intended to mean condensate at a temperature higher than the temperature of the condensate supplied to the process fluid heat exchanger 206'.

[0079] In some examples, the heat pump 200' may further include a pressurization device (not shown) configured to pressurize the process fluid stream 202' and / or the heated process fluid stream 208' such that the process fluid stream and / or the heated process fluid stream 208' is / are maintained in the liquid phase during use.

Claims

[1] A heat pump for receiving an exhaust steam stream and generating a process steam stream in use, the heat pump, arranged in series in a closed circuit, comprising: an exhaust steam condenser; a compressor fluidly connected to the exhaust steam condenser; a process steam generator fluidly connected to the compressor; an expansion valve fluidically connected to the process steam generator, wherein the exhaust evaporator is fluidly connected to the expansion valve; such that, in use, a coolant can circulate in the closed circuit; wherein the compressor is configured to increase the pressure of the coolant to increase the temperature of the coolant during use; wherein the expansion valve is configured to reduce the pressure of the refrigerant to reduce the temperature of the refrigerant in use; wherein the exhaust steam condenser is configured to receive an exhaust steam stream and transfer heat from the exhaust steam stream to the coolant in use; and wherein the process steam generator is configured to receive water and transfer heat from the coolant to the water to generate a process steam stream in use. [2] Heat pump according to claim 1, wherein the heat pump is a high temperature heat pump. [3] A heat pump according to claim 1 or 2, wherein the heat pump further comprises one or more of the following: one or more receivers; instrumentation(s); oil separator(s); valve(s); buffer tank(s); internal heat exchanger(s); recuperator(s). [4] A heat pump according to any one of the preceding claims, further comprising a pressurising device configured to pressurise water provided to the process steam generator such that the water provided to the process steam generator is maintained in the liquid phase until the water reaches the process steam generator in use. [5] A heat pump system for receiving an exhaust steam stream and generating a process steam stream in use, the heat pump system comprising: a heat pump according to one of claims 1 to 4; a coolant provided in the closed circuit; an exhaust steam stream provided to the exhaust steam condenser; and a water stream provided to the process steam generator. [6] A heat pump for receiving an exhaust steam stream and heating a process fluid stream in use, the heat pump comprising, arranged in series in a closed circuit: an exhaust steam condenser; a compressor fluidly connected to the exhaust steam condenser; a process fluid heat exchanger fluidly connected to the compressor; an expansion valve fluidly connected to the process fluid heat exchanger, wherein the exhaust steam condenser is fluidly connected to the expansion valve; so that during use a coolant can circulate in the closed circuit; wherein the compressor is configured to increase the pressure of the refrigerant to increase the temperature of the refrigerant in use; wherein the expansion valve is configured to reduce the pressure of the refrigerant to reduce the temperature of the refrigerant in use; wherein the exhaust steam condenser is configured to receive an exhaust steam stream and transfer heat from the exhaust steam stream to the refrigerant in use; and wherein the process fluid heat exchanger is configured to heat a process fluid stream by transferring heat from the coolant to the process fluid stream in use. [7] The heat pump of claim 6, wherein the process fluid heat exchanger is configured to heat a process fluid stream comprising water. [8] The heat pump of claim 6, wherein the process fluid heat exchanger is configured to heat a process fluid stream comprising thermal oil or condensate from an industrial process. [9] Heat pump according to one of claims 6 to 8, wherein the heat pump is a high-temperature heat pump. [10] A heat pump according to any one of claims 6 to 9, wherein the heat pump further comprises one or more of the following: one or more receivers; instrumentation(s); oil separator(s); valve(s); buffer tank(s); internal heat exchanger(s); recuperator(s). [11] A heat pump according to any one of claims 10, further comprising a pressurising device configured to pressurise the process fluid stream to maintain the process fluid stream in the liquid phase in use. [12] A heat pump system for receiving an exhaust steam stream and heating a process fluid stream in use, the heat pump system comprising: a heat pump according to one of claims 6 to 11; a coolant provided in the closed circuit; an exhaust steam stream provided to the exhaust steam condenser; and a process fluid stream provided to the process fluid heat exchanger.

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