System for the extraction of heat and supply to heating apparatus

Abstract

A system for provision of heat to heating apparatus 36 includes a heat source, one or more heat pumps 24, and a heat exchange arrangement 18,18’,21. The heat exchange arrangement transfers thermal ene

Description

The invention to which this application relates is to a system for the extraction of heat from a water mains and in particular. The reduction in heating by using carbon fuels is a worldwide aim. For example, the UK government has made a commitment to achieve net zero carbon emissions by 2050. To achieve this target, the decarbonisation of heat is a key contributing factor as currently heating and hot water supply for UK buildings accounts for approximately 40% of the UK’s energy consumption and 20% of CO2 emissions. One known form of apparatus which can be used as an alternative to conventional oil or gas boilers that require fossil fuels to generate heat. Heat pumps operate through the use of an evaporator and condenser in fluid communication with each other, requiring a relatively low heat input to induce evaporation of a Equid in a reduced pressure state. This relatively low heat input may be suppked from the surrounding air in air source heat pumps or extracted from the ground in ground source heat pumps. Due to the relatively low thermal conductivity of air, it is found that ground source heat pumps have a greater efficiency. Ground source heat pumps require pipelines to be installed at a depth sufficient to extract heat from the Earth’s core, such that fluid pumped through the pipelines can transfer the extracted heat to a heat pump located on the earth’s surface. Ground source heat pumps are costly to install, as the pipelines must be located relatively deeply beneath the Earth’s surface, requiring costly installation and are difficult to access for the purposes of maintenance. It is also the case that in operation, ground source heat pumps only contribute a relatively small amount to the reduction in use of carbon fuels. There is therefore a need to extract heat in a manner which can be utilised effectively, and another known source is sewage networks. Sewage pipelines contain liquid flow in which bacteria and other biological matter cause chemical reactions that inherently raise the temperature of the flow. Furthermore, as the sewage flow is passed towards a treatment facility, there is no requirement to prevent contamination of the flow in a heat extraction process. Heat exchange apparatus such as mats or the like may be embedded within the sewage pipelines or the walls of the pipelines, allowing the heat exchange apparatus to be submerged in the sewage flow and extract heat therefrom which can be subsequently supplied to heating systems such as in one or a group of domestic premises. However, there is still a requirement to expand the source of accessible heat beyond the existing sewage lines. An aim of the present application is therefore to provide a system for the extraction of heat from a mains water supply system, wherein there is no risk of contaminating the water supply. In a first aspect of the invention there is provided a system for the provision of heat to heating apparatus, said system including; a heat source, one or more heat pumps, and a means for thermal transfer of heat from the heat source to the heat pump wherein said means for thermal transfer is located intermediate the heat source in the form of a treated or raw water pipeline and the said one or more heat pumps. In one embodiment the heating apparatus is provided in one or a plurality of buildings to provide heat therein and is connected to receive heat from the said one or more heat pumps. In one embodiment the treated or raw water pipeline is an offtake conduit from a water trunk mains supply of a water supply network. In one embodiment the portion of the water from the water trunk mains supply is diverted along the offtake conduit and then rejoins the water trunk main supply at a location downstream. In one embodiment the said portion of the water which is diverted is such as to minimise any drop and / or temperature change of the water passing along the water trunk main supply. In one embodiment the said means for thermal transfer includes a pipe or tube through which a refrigerant flows and said pipe or tube has a first portion adjacent the said water. In one embodiment the said first portion is sufficiently close or in contact with the offtake conduit so as to allow thermal transfer between the water and the refrigerant. In one embodiment the said first portion is coiled around the said offtake conduit and defines a passage through which the offtake conduit passes. In an alternative embodiment, or in addition, the said first portion is positioned so as to allow refrigerant to pass through the interior of the water trunk mains supply. In a yet further embodiment, or in addition to the previous embodiments the said first portion is positioned so as to allow refrigerant to pass along a wall of the water trunk mains supply pipeline. In one embodiment a further portion or portions of the said pipe or tube are located adjacent an evaporator of the one or more heat pumps. In one embodiment the said further portion or portions are coiled around the respective evaporator. In one embodiment the said means for thermal transfer is a closed circuit and a refrigerant is induced to flow around said circuit by a pump. In one embodiment the refrigerant incudes ethanol or a mixture including ethanol. In one embodiment the refrigerant has a maximum temperature of -10 degrees Celsius. In one embodiment the thermal transfer means pipe or tube is formed of stainless steel. In one embodiment the thermal transfer means is monitored to identify any failures and if a failure is detected, the thermal transfer means is isolated to ensure no cross contamination with the water supply network. In one embodiment a plurality of means for thermal transfer are provided along a water trunk mains supply. In one embodiment the water trunk mains supply supplies water to the building or buildings heated by the heating system in accordance with the invention. In one embodiment the heat source is an offtake diverted from a water network. In this embodiment, a proportion of the water from the water mains network is provided as a source of heat for the heating system, reducing the likelihood of significant pressure drop and / or temperature change within the water supply network when the offtake is diverted back to the network. In one embodiment the water network system includes any of a series of valves, pipes and / or other flow control means so as to control the parameters of the water to predetermined levels suitable for the extraction of heat. Preferably at least one parameter is that the pressure is suitable for customer supply and that to extract heat. In one embodiment the refrigerant includes ethanol or a mixture including ethanol. Typically, the refrigerant further includes water. In this way, the freezing temperature of the refrigerant is reduced. In one embodiment the heating system is configurable to extract heat from a building or buildings supplied by the same. Specific embodiments of the invention will now be described with reference to the following drawings, wherein: Figure 1 illustrates schematically a system for the extraction of heat from a water trunk main conduit in accordance with the invention. Referring to Figure 1, there is illustrated a water trunk main supply 2 supplying water to a number of buildings 4. Each building 4, in this example a residential property, is supplied by a reticulated conduit 6 from the water trunk main supply 2. The water trunk main supply 2 is below the ground surface 8. The water trunk main supply 2 supplies potable, or drinkable, water 3 under pressure to the locations serviced by the reticulated conduits 6 of the same. Typically, the water main trunk supply lines 2 are provided in diameters within the range of 12 inches to 48 inches. Typical flow rates vary from a minimum of 23 1 / s for 12-inch pipes to a maximum of 1624 1 / s for 48-inch pipes, depending on hydraulic gradient. In the colder winter months, the temperature of the supply water is typically found to vary between 5.5 degrees Celsius and 15.5 degrees Celsius. In accordance with the invention, an offtake conduit 10 is configured to divert a portion 12 of the water supply from the water trunk main supply 2. The diameter and length of the offtake conduit 10, as well as the angle of flow of the diverted portion 12 are selected to reduce and minimise any pressure drop along the water trunk main supply 2 between the offtake conduit inlet 14 and outlet 16 as much as possible. In alternative embodiments, a pump (not shown) is provided at or along the offtake conduit 10 so as to assist in the maintenance of the pressure within the water trunk main supply. Typically the said pressure of the supply flow 12 along the offtake conduit is provided to be at least 3 bar. In accordance with the invention as illustrated a pipe or tube 18 is provided which at portion 18’ is coiled so as to form a passage through which the offtake conduit passes. The coiled pipe or tube has a flow of refrigerant therethrough and the tube 18 is located around the offtake conduit and in one embodiment in contact therewith and, in any case, so that the refrigerant flows around the external surface of a portion of the length of the offtake conduit 10 and in close proximity to the water within the offtake conduit. The refrigerant coiled pipe or tube 18 is typically formed of stainless steel and ensures that the refrigerant within the conduit is separated from the water flowing along the offtake conduit 10 and water 12 flowing therealong and so prevents the risk of contamination of the water, whilst still allowing the refrigerant and water to be in a thermal transfer relationship with each other. Typically the refrigerant within the coiled pipe or tube 18 is induced to flow therealong by a pump 20. Another portion 21 of the pipe or tube is coiled to pass about an evaporator 22 of a heat pump 24 to transfer heat from the refrigerant to the evaporator, before returning to the conduit 10. In this way, heat that is extracted from the offtake conduit 10 in direction 26 is transferred to the evaporator 22, and the reduced temperature refrigerant is reintroduced into thermal contact with the conduit 10 in direction 28. The heat pump 24 can have any configuration as known in the art. In this example, the evaporator 22 contains a low pressure Equid that is evaporated by the heat suppked from the refrigerant at the coiled portion of 21 of pipe or tube 18 to form low pressure vapour that passes through a compressor 30. The resulting high-pressure vapour is condensed within the condenser 32 and so producing heat that is transferred to a refrigerant conduit 34 to supply a heating element 36 of the heating supply system of the budding 4. The high-pressure Equid then passes from the condenser 32 back to the evaporator 22 via an expansion valve 38, reducing the pressure and temperature of the liquid which can then be evaporated and heated again. In one example of the use of the system, if the average flow rate of the water through the offtake conduit 10 is 1157 Etres / second and the water has a temperature of 10 degrees Celsius then by extracting heat of 3 degrees Celsius from the water via the coded pipe or tube portion 18’ and refrigerant, it is calculated by using the heat transfer equation: heat transfer (kW) = mass flow rate (1 / s) x specific heat in kcal / (kg*K) — Cp water=4.18kcal / (kg*K) x the difference in temperature before and after heat exchange then the potential energy which can be extracted is approximately 14.5MW by the system. The system may be retrofitted with an existing water trunk main supply 2, without the requirement for turning off the supply for an extended period of time and by using existing access points. Typically the heat pump will be sized to meet peak thermal power load, although it may be more economical to size the heat pump to meet a proportion of the design load, such as 60% of the design heating load. In one embodiment an auxiliary heating system may be provided to meet peak demand. The current invention of utilising heat transfer from mains water trunk supplies represents a significant amount of energy which, if extracted, provides a carbon free heat supply to individual or district heating supply systems. The most efficient utilisation of the system will be achieved when the closest possible thermal transfer is achieved between the water and refrigerant without risk of contamination to the water supply, as is achieved in a practical manner in the invention as herein defined.

Claims

1. A system for the provision of heat to heating apparatus, said system including; a heat source, one or more heat pumps, and a means for thermal transfer of heat from the heat source to the heat pump wherein said means for thermal transfer is located intermediate the heat source in the form of a treated or raw water pipeline and the said one or more heat pumps.

2. A system according to claim 1 wherein the heating apparatus is provided in one or a plurality of buildings to provide heat therein and is connected to receive heat from the said one or more heat pumps.

3. A system according to claim 2 wherein the treated or raw water pipeline is an offtake conduit from a water trunk mains supply of a water supply network.

4. A system according to claim 3 wherein a portion of the water from the water trunk mains supply is diverted along the offtake conduit and then rejoins the water trunk main supply at a location downstream.

5. A system according to claim 4 wherein the said portion of the water which is diverted is such as to minimise any drop and / or temperature change of the water passing along the water trunk main supply.

6. A system according to any of the preceding claims wherein the said means for thermal transfer includes a pipe or tube through which a refrigerant flows and said pipe or tube has a first portion adjacent the said water.

7. A system according to claim 6 wherein the first portion is sufficiently close or in contact with the offtake conduit so as to allow thermal transfer between the water and the refrigerant.

8. A system according to claims 6 or 7 wherein the said first portion is coiled around the said offtake conduit and defines a passage through which the offtake conduit passes.

9. A system according to any of claims 6-8 wherein the said first portion is positioned so as to allow refrigerant to pass through the interior of the water trunk mains supply.

10. A system according to any of claims 6-9 wherein the said first portion is positioned so as to allow refrigerant to pass along a wall of the water trunk mains supply.

11. A system according to any of the claims 6-10 wherein a further portion or portions of the said pipe or tube are located adjacent an evaporator of the one or more heat pumps.

12. A system according to claim 11 wherein the said further portion or portions are coiled around the respective evaporator.

13. A system according to any of the preceding claims wherein the said means for thermal transfer is a closed circuit and a refrigerant is induced to flow around said circuit by a pump.

14. A system according to any of claims 6-13 wherein the refrigerant incudes ethanol or a mixture including ethanol.

15. A heated system according to any of claims 6-14 wherein the refrigerant has a maximum temperature of -10 degrees Celsius.

16. A system according to any of the claims 6-15 wherein the thermal transfer means pipe or tube is formed of stainless steel.

17. A system according to any of the preceding claim wherein the thermal transfer means is monitored to identify any failures and if a failure is detected, the thermal transfer means is isolated to ensure no cross contamination with the water supply network.

18. A system according to any of the preceding claims wherein a plurality of means for thermal transfer are provided along a water trunk mains supply.IntellectualPropertyOfficeApplication GB2507277.8Search report under Section 17 of the Patents Act 1977Date search completed: 06 November 2025Claims searched: 1 at leastInternational classificationSubclass and subgroup Valid from F24D15 / 04 01 / 01 / 2006 F24D3 / 18 01 / 01 / 2006Field of searchWorldwide search of patent documents classified in the following areas of the IPC:F24D, F24H, F25BDatabases used in the preparation of this search report:SEARCH-PATENTDocuments considered to be relevantPatent literatureCategory Relevant Document of relevanceclaimsX 1 at least EP 2163828 A2 (GEOGEN SYSTEMS LTD) See figure 1 noting heating system for a location 13, the system comprising a heat pump 24 that draws thermal energy from an offtake pipe 11,12 of a mains supply pipe 10 [i.e. heat source / water pipeline] via a heat exchanger 12 [i.e. means]. X 1 at least US 6041613 A (MORSE and NUTT) See figure 4 noting air conditioning system comprising a water source heat pump 225 that draws thermal energy from an offtake conduit of a city water main 260 [i.e. heat source / water pipeline] via an isolating heat exchanger 265 [i.e. means]. X 1 at least GB 2582137 A (ICAX LTD) See figure 2 noting heat pump system comprising a dual source heat pump 210 that draws thermal energy from a utility supply 240 that includes a potable water network [i.e. heat source / water pipeline], whereby thermal connection between the utility supply and the dual source heat pump 210 may be directly or via a heat exchanger [i.e. means]. X 1 at least US 6688129 B2 (ACE) See figure 6 noting geothermal heating and cooling system comprising a heat pump 62 that draws thermal energy from a sewer line 144 [i.e. heat source / water pipeline] via a heat exchange coil 140 [i.e. means].Non-patent literatureCategory Relevant claims Document of relevanceCategoriesLetter or DescriptionsymbolLetter or symbol Description X Document indicating lack of novelty or inventive step.Y Document indicating lack of inventive step, if combined with another document of the same category. & Member of the same patent family. A Document indicating technological background. P Document published on or after the priority date but before the fling date of the present application. E Earlier application published on or after the filing date of the present application.

Images