NO333410B1 - Method and apparatus for optimal use of heat energy - Google Patents

Abstract

A method and system for optimal use of heat produced in a thermal system on board a marine unit, the thermal system comprising one or more heat generating units (11,13,21,23) and one or more heat consuming units (12) with a associated pipeline system (23,24,26) and valve system for circulating thermal fluid between the various units, wherein the heat generating units (11,13,21,23) comprise at least one fuel-fired burner (11); at least one thermal fluid cooling unit (21) selected from the group of cooling systems on one or more engines (20), exhaust gas economizers (22) associated with the exhaust gas line (s) from said one or more engines (20) and / or garbage burners (13), wherein from the cooling systems of the heat generating units (11,13,21,23) are recovered and used for the supply of heat to heat-consuming units (12), the thermal system being configured in such a way that heat recovered from the heat recovery generators ( 11,13,21,23) is used primarily, and that heat supplied from the conventional burners (11) is only used or used as a supplement, if heat from the heat recovery generators (11,13,21,23) is not used is sufficient for the desired purpose.

Description

Technical field of the invention

The present invention relates to a method and a thermal system for optimal use of heat produced on board a vessel, comprising one or more heat-generating units and one or more heat-consuming units with an associated pipeline and valve system for circulation of said thermal fluid between the various units, said heat generating unit(s) comprising at least one fuel-fired burner; for example at least one cooling unit for cooling the thermal fluid selected from the group of the cooling system for one or more engines), exhaust gas economizing units associated with exhaust waste from one or more engines and/or for example one or more waste burners, as heat from the cooling systems to said heat-generating unit(s) are recovered and used for the supply of heat to at least one heat-consuming unit.

Background for the invention

For central heat production in a thermal system on board a marine unit, each unit that produces work or that generates heat is equipped with heat exchangers to cool and to maintain the unit at a predetermined temperature and where such recovered heat is transferred to a circulating cooling fluid. Such devices can be, for example, an engine, the exhaust system associated with the engine(s), and fuel-driven burners. The fuel-driven burner can optionally be connected to the system, depending on the availability and adequacy of green energy supplied by other units. Also other systems, such as waste incinerators, and so on, can be incorporated into the thermal system. The different units may be connected to each other by means of a pipe system or circulation pipe, which connects the different units in parallel and which includes manifolds and valves. The circulation of the cooling fluid can be achieved by means of a main circulation pump which supplies heat to various user units on board the vessel.

From DE 102008064015 and FR 23537150 it is known to use waste heat from an internal combustion engine, where the exhaust heat is used to transform this waste heat into usable energy. While FR 23537150 relates to the use of such waste heat on board a ship, DE 103008064015 targets the use of the heat from exhaust gases in connection with a turbocharger in a motor vehicle. FR 23537150 relates to a system linked to turbocompressors for the main machinery of a vessel. There is no indication in FR 23537150 about the utilization of excess heat from other heat-producing units on board a vessel, nor the management of the delivery and/or use of such excess heat to other heat-consuming devices on board.

Two articles, which are available from the Internet, concern the reuse of waste heat in connection with ships. These are dated 210.03.07 and are available at the links: http;// www. aalborg industries. com/ global after sales/ WHR eco after eux engines. php, and http:// ipaperjpapercms. dk/ Aalbordlndustries/ mbhe/ Datasheets/ MISSIONXS7WRAfterAuxEn gines/

Both of these articles relate to the reuse of waste heat and the purpose of the solutions described in these two articles is to recover and use recovered heat from machinery on board a vessel, where heat from auxiliary machinery is also recovered.

Summary of the invention

When referring to the term "green energy" below, the following types of energy are meant: Heat that is recovered as a secondary energy from a working machine or engine; and which or would be lost if not recovered. This type of energy can be, for example, energy recovered from the engine cooling systems, energy recovered by cooling the exhaust gases produced by the combustion in an engine, heat recovered from the waste incinerators, heat produced as a secondary effect in other types of work machines or in the air conditioning system, and so on.

An object of the invention is to provide a method and a system for reducing the energy consumption required to heat up heat-consuming devices on board a marine installation or a vessel.

Another purpose of the present invention is to lay the basis for optimal use of energy produced by machinery on board a vessel in periods of variable load on the vessel's machinery, such as, for example, a service or supply ship that works offshore, a vessel that often must maneuver in to or out of and/or along the coastline, and so on.

Another object of the invention is to recover and utilize green energy as much as possible for the supply of heat to heat-consuming appliances, equipment and machinery.

Another purpose of the invention is to provide a method and a system to enable a more economical and more optimal use of generated heat, thereby reducing the need to burn more fuel to heat up different systems.

Yet another purpose of the invention is to utilize waste heat produced by engine and waste incineration systems in a sustainable manner.

A further object of the invention is to reduce the total fuel consumption to drive and operate a vessel.

The purposes are achieved with the help of a method and a system which are defined in more detail in the independent patent claims, while embodiments and alternatives are defined in the non-independent patent claims.

According to the present invention, the sanitary water generator is integrated into the fuel-driven burner, which allows water to be heated using "green heat" by allowing it to pass through the burner to be further heated.

A further feature of the present invention is that controlled valves, which are connected to the various parallel units and the pipe system, are equipped with parallel loops for each unit in the thermal system. The control of the valves is achieved by means of a control console, for example centrally arranged in the engine room of the vessel. With the help of such controlled valves and said control console, it is possible to achieve a balanced flow throughout the system by directing the flow to devices that produce heat at any given time and/or to direct heated water to devices that need the supply of heat . The system can also be equipped with one or more by-pass lines with associated control valves, which improves the controlled and balanced flow in the system and consequently, together with the control of the other valves in the system, ensures an optimal flow that delivers the required heat volume to the desired unit wherever and whenever necessary.

The system also includes sensors and meters to measure flow rates, pressure and temperature at relevant points in the system. The recorded values obtained by said sensors are used to achieve automatic control of the control valves, thereby achieving an optimal reduction in the use of fuel to drive the vessel.

According to the invention, heat is recovered from the heat-generating units' cooling system and the heat used for the delivery of heat to the heat-consuming units, the thermal system being configured in such a way that the heat recovered from the heat-recovering generators is used in the first instance and that heat supplied from conventional fuel-powered burners only, or as a supplement, are used if the heat from the heat recovery generators is not sufficient to achieve the required heat delivery.

In particular, but not exclusively, temperatures, pressure and/or current are measured by sensors arranged on the various units in the thermal system, as such measurements are transferred to a computer system where the values are compared with set values and where control signals are communicated to automated valves for opening or closing such valves to achieve an optimal delivery of heat to the heat-consuming unit(s).

The heat-generating unit or units and the heat-consuming unit or units can preferably be divided into separate temperature loops and connected together for optimal energy saving. The thermal circulation lines for each thermal generating unit and each circulation line for the heat consuming units can preferably be arranged in parallel to thereby allow individual supply of heat from or to said units, depending on the level of available heat.

According to the present invention, the thermal fluid can circulate in a forced manner in the pipeline system by means of at least two circulation pumps, the operation and standby of the pumps being controlled by a control unit, depending on the available heat and the required flow of thermal fluid to meet the set values for the heat-consuming units.

Correspondingly, the system depends on heat supplied by the cooling systems of the heat-generating units being recovered and used for delivery to said at least one heat consumer, the thermal system being configured in such a way that the heat from the heat-recovery generators is used primarily, and that conventional fuel burners are used for the production of heat only, or as a supplement, if the heat from the heat recovery generators is not sufficient to achieve the required temperature.

According to one embodiment, the pipeline system comprises sensors and communication devices for producing and sending signals between the heat-generating units and the heat-consuming units. The system also includes a control unit and remotely operated valves associated with the heat-generating and heat-consuming units, controlled by the control unit.

The heat-generating unit or units and the heat-consuming unit or units can preferably be divided into separate temperature loops and connected together for optimal energy saving. Furthermore, the thermal fluid circulation lines for each heat generating unit and each circulation line for the heat consuming units are arranged in parallel to allow individual supply from or to said units, depending on the level of heat available.

According to one embodiment, the system can comprise at least two circulation pumps, where operation and stand-by are controlled by a control unit, depending on the required flow of thermal fluid to meet the set values.

According to the present invention, it is possible to automatically regulate and control the fluid flow of hot water to units where it is possible to collect and add heat to the fluid and then circulate such fluid to consuming units, thereby collecting heat in an optimal way.

The system can also be configured in a simple and uncomplicated way with regard to the required number of heat-generating units and heat-consuming or heat-demanding units.

The system consists of few components, all of which are available on the market on a commercial scale. In addition, the system is easy to install as it consists of a limited number of components.

It must also be stated that the system is configured in such a way that it can be controlled automatically, for example by a PLC system. In this way, it can become possible to record and log all the readings and trends of values to report from an environmental point of view. In this way, it may be possible in a more optimal and economical way to use "green energy" and to achieve a more optimal and economical operation.

Brief description of the drawings

An embodiment of the present invention will now be described in more detail with reference to the accompanying drawings, where: figure 1 schematically shows a simplified arrangement and flow diagram indicating the principles used according to the present invention;

figure 2 schematically shows the arrangement and flow diagram of a marine installation or a vessel, various heat generating units, heat consuming units, pipelines for circulation of thermal fluid and the communication lines for signals between the sensors and valves and the control unit are indicated; and

figure 3 schematically shows on an enlarged scale parts of the arrangement and the flow diagram shown in figure 1.

Details description of the invention

Figure 1 shows the arrangement and flow diagram of a thermal system 10 on board a marine installation or vessel (not shown). In principle, the thermal system 10 comprises different heat-generating units, such as a fuel-driven burner 11, heat-consuming units, such as an oil tank 12 or a waste incinerator 13, a pipe system comprising pipes 14 with valves 15 for circulating a thermal fluid through the system 10 and which connects the heat-generating units and the heat-consuming units. A main circulation pump 16 is connected to the pipe system to ensure the circulation of the heat-carrying fluid through the system. The thermal system 10 further comprises bypass lines 18 with associated valves 25.

As further indicated in Figure 1, the thermal system also includes a control and measurement system to control the valves 25 and the pump 16 to thereby ensure optimal heat production and delivery in the system 10. The control and measurement system preferably includes remote control of the valves for individual opening and closing of these and sensors and meters for sensing temperature and for measuring the pressure and/or flow rate through the pipe system at relevant points in it. For this purpose, the thermal system 10 comprises communication lines 40 which communicate signals to the activatable valves and to transmit signals to or from the control or measurement system to and/or from a control unit 17.

The thermal system 10 shown is a closed, pressurized heating system for marine installations based on the circulation of thermal fluid, such as water or glycol, in the pipeline system 14 and with a working temperature of up to 110 °C. The working pressure is normally up to 3 bar.

Figure 2 schematically shows the arrangement and the flow diagram for a vessel or a marine installation. The thermal system shown in Figure 2 is a more detailed embodiment of the system shown in Figure 1. The thermal system 10 generally comprises a main circulation line 24 which circulates fluid by means of one or more main circulation pumps 16. According to the embodiment shown, two identical pumps are used mounted on a skid. One pump can run, while one pump is in stand-by, as each pump has a capacity to deliver heated fluid for the total heat consumption. Alternatively, one pump can be dimensioned for maximum heat consumption, while the other can be configured for 50% heat consumption/stand-by.

The thermal system 10 according to the embodiment shown includes four engines 20, for example propulsion and/or auxiliary machinery. Each engine 20 is equipped with an HT cooling system 21 for cooling the engines 20, the cooling system 21 including devices for heat exchange which can be used for the production of "green energy" in the thermal system according to the invention. The flow of heated coolant from the heat exchanger in each cooling system 21 is countercurrent to the cooling of the engine. Said flow of heated fluid from each engine is further arranged in parallel by means of the pipeline 23, the ends of the pipeline 23 being connected to the main circulation pipeline 24 in parallel, while they are connected to the burner in series. At least one activatable valve 25 is incorporated in the pipeline 22 for heated fluid.

The exhaust gas from each engine 20 is also cooled by means of an exhaust gas economizer 22. Correspondingly, fluid heated by the heat exchanger in the exhaust gas economizer 22 flows in corresponding pipelines 26 which pass through a countercurrent heat exchanger incorporated in the exhaust gas economizer 22. Said pipeline 26 for the various exhaust gas economizers is also arranged in parallel and includes activatable valves 27. The exhaust gas economizer may preferably have an automatic by-pass regulation for minimum and maximum exhaust gas temperature and may include an automatic control system.

A fuel-driven burner 11 is incorporated in the main circulation line 25 for heating the circulating fluid in the main circulation line 24 for those cases where the "green energy" from the engines and/or exhaust gas economizers, and possibly also the waste incinerator 13, is not sufficient to provide the required heat. A conventional expansion tank 29 is also incorporated in the main circulation line 24. The fuel-fired burner 1 is preferably used as the primary heat source for heating fresh water in a separate but integrated sanitary water system with a burner 11, since such sanitary water must be fresh water and not necessarily glycol or other types of fluids, which may be the case for fluid that is circulated through the main circulation line 24. Said system for sanitary water is of a conventional type that is well known to the person skilled in the field, and where the water is delivered by means of a pump 30.

The heated water is further delivered to heat-consuming units 12 of various types, such as liquid tanks, and the like. The circulation lines 32, i.e. the supply lines and outlet lines, for each unit 12 are arranged in parallel and are also equipped with activatable valves 33, arranged upstream of the heat consuming unit 12. A bypass line 31 is arranged at this end to allow the pumped fluid to pass past all the heat-consuming units 12, or at least a large part of said units 12.

Each of the activatable valves is connected to a control cabinet 17 to allow an operator or a computer to regulate the opening and closing of the valves, fully or partially, depending on the desired rate of heat required. When using a fully automated system, such an automated system may include computer hardware and software: this may be connected to the control cabinet 17. The wires to transmit signals from the sensors and meters in the system and the wires to communicate with the control cabinet 17/it The automatic system is also incorporated into the system. The control cabinet can, for example, have a 15 inch touchscreen which shows a mimic diagram for the main pipeline components and which can also show temperatures, pressure and valve status and can also include an alarm display. The device can also have a user interface for system operation and parameter setting. The system can also have an interface to IAS.

Figure 3 schematically shows on an enlarged scale parts of the arrangement and the flow chart shown in Figure 2.

The thermal system according to the present invention primarily uses excess energy from the heat-recovering generators associated with, for example, propulsion machinery, auxiliary engines and the exhaust gas systems associated with such engines. The system is only based on the use of fuel burners 11 if and when "green energy" from the heat-recovery generator system is not sufficient to heat the various units 12 well enough to the desired temperatures.

As indicated above, the system is automatically controlled and monitored by a control system and can be interfaced to the main computer system (IAS). The safety control system and the system for manual control are standard delivery. The control system is of a type that is approved by the major classification societies and according to the class notification EO.

The control system is PLC-based and automatically controls the thermal fluid flow to the individual groups of heat generators and the groups of heat-consuming units and balances the system in an optimal way. It also controls the exhaust gas outlet temperature in the exhaust gas economizer to avoid too low temperatures in the exhaust gas system.

The circulation system is operated by two or more main circulation pumps 16. The functions for driving and stand-by are built into the control system. The current to the specific heat generator and heat consumer is automatically controlled by motor-controlled valves that operate from 0-100%. Manual steering and emergency steering are standard delivery.

The heat generators and the heat-consuming units can be divided into separate temperature circuits and can be connected together for optimal energy saving. It should further be stated that in addition to the above-mentioned main parts described above, the system may also contain pipes and additional equipment, such as manual valves, temperature gauges, pressure gauges, and so on, which are well known to the skilled person in the field and which are consequently not described here.

Claims (10)

1. Procedure for optimal use of heat energy produced in a heating system on board a vessel, where the heating system comprises one or more heat-generating units (11,13,21,23) and one or more heat-consuming units (12) with an associated pipeline (23 . a heat exchange unit (21) for cooling/heating said thermal fluid, selected from the group of one or more engines (20), exhaust gas economizer (22) associated with exhaust line(s) from said one or more engines (20) and/or waste incinerator -units (13), the heat from the cooling system of said heat generating unit(s) (11,13,21,23) being recovered for supplying heat to a heat consuming unit(s) (12), characterized in that the extraction and/or delivery of heat in the thermal system is controlled using a control system, so that heat recovered from the heat-recovery generators (11,13,21,23) is primarily used and that heat delivered from the conventional fuel burners or the electric heat generators are only used, or are used as a supplement, if the heat from said heat recovery generators (11,13,21,23) is not sufficient to meet the desired need. 2. Method according to claim 1, where temperatures, pressure and/or flow rate(s) are measured by sensors arranged on the various units in the thermal system, such measurements being transferred to a computer system where the values are compared with set values and where control signals are sent to automated valves (15,25,27,33) for opening or closing such valves (15,25,27,33) in order to thereby achieve an optimal recovery of heat from the heat-generating units and optimal distribution of heat to said heat-consuming unit(s) (12). 3. Method according to claim 1 or 2, where said heat-generating unit(s) and said heat-consuming unit(s) (11,13,21,23) are divided into separate temperature circuits and connected together for optimal energy saving. 4. Method according to one of claims 1 to 3, wherein said circulation lines (23,26) for the thermal fluid for each heat-generating unit (11,13,21,23), and each circulation lining (32) for said heat-consuming unit(s) (12) is arranged in parallel, thereby allowing individual supply from said units, depending on the extent of available heat. 5. Method according to one of claims 1 to 4, where the thermal fluid is circulated through the pipeline system by means of at least two circulation pumps (16), where operation and stand-by are controlled by a control unit, depending on the required flow of thermal fluid to reach the set values. 6. Thermal system for optimal use of heat produced on board a vessel, comprising one or more heat-generating units (11,13,21,23) and one or more heat-consuming units (12) with an associated pipeline and valve system for circulation of said thermal fluid between the different units, said heat generation unit(s) (11,13,21,23) comprising at least one fuel-fired burner (11); for example, at least one cooling unit for cooling the thermal fluid selected from the group of the cooling system for one or more engines (20), exhaust gas economizing units (22) associated with exhaust drains from one or more engines (20); and/or for example one or more waste burners (13), as heat from the cooling systems of said heat-generating unit(s) (11,13,21,23) is recovered and used for the delivery of heat to at least one heat-consuming unit (12), characterized in that the thermal system comprises a control system which is configured such that heat recovered from said heat-recovery generator(s) (11,13,21,23) is primarily used first and that heat from said least one fuel-fired burner (11) is first used, possibly supplemented, if heat from said heat-recovery generators (11,13,21,23) is not sufficient to achieve the desired temperature. 7. System according to claim 6, where the pipe system comprises sensors and communication devices for providing and sending a signal between said heat-generating unit(s) (11,13,21,23) and said consuming unit(s) (12) and a control unit for remote control of the valves associated with said heat-generating unit(s) (11,13,21, 23) and said heat-consuming unit(s) (12), controlled by the control unit. 8. System according to claim 6 or 7, where said heat-generating unit(s) (11,13, 21,23) and said heat-consuming unit(s) (12) are divided into separate temperature circuits and connected to each other for optimal energy recovery. 9. System according to one of claims 6 to 8, wherein the thermal fluid circulating line for each heat generating unit (13,21,23) and each circulating line for said heat consuming unit (12) are arranged in parallel to allow individual supply from or to said units, depending on the level of heat available. 10. System according to one of claims 6 to 9, where the system comprises at least two circulation pumps (16), where operation and stand-by are controlled by a control unit, depending on the required flow rate to meet the set values..