Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24D—DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR
  • F24D3/00—Hot-water central heating systems
  • F24D3/08—Hot-water central heating systems in combination with systems for domestic hot-water supply
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24D—DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR
  • F24D11/00—Central heating systems using heat accumulated in storage masses
  • F24D11/02—Central heating systems using heat accumulated in storage masses using heat pumps
  • F24D11/0214—Central heating systems using heat accumulated in storage masses using heat pumps water heating system
  • F24D11/0221—Central heating systems using heat accumulated in storage masses using heat pumps water heating system combined with solar energy
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24D—DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR
  • F24D17/00—Domestic hot-water supply systems
  • F24D17/0026—Domestic hot-water supply systems with conventional heating means
  • F24D17/0031—Domestic hot-water supply systems with conventional heating means with accumulation of the heated water
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24D—DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR
  • F24D17/00—Domestic hot-water supply systems
  • F24D17/0036—Domestic hot-water supply systems with combination of different kinds of heating means
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24D—DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR
  • F24D17/00—Domestic hot-water supply systems
  • F24D17/02—Domestic hot-water supply systems using heat pumps
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24D—DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR
  • F24D19/00—Details
  • F24D19/10—Arrangement or mounting of control or safety devices
  • F24D19/1006—Arrangement or mounting of control or safety devices for water heating systems
  • F24D19/1066—Arrangement or mounting of control or safety devices for water heating systems for the combination of central heating and domestic hot water
  • F24D19/1072—Arrangement or mounting of control or safety devices for water heating systems for the combination of central heating and domestic hot water the system uses a heat pump
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
  • F24H15/00—Control of fluid heaters
  • F24H15/20—Control of fluid heaters characterised by control inputs
  • F24H15/212—Temperature of the water
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
  • F24H15/00—Control of fluid heaters
  • F24H15/30—Control of fluid heaters characterised by control outputs; characterised by the components to be controlled
  • F24H15/355—Control of heat-generating means in heaters
  • F24H15/37—Control of heat-generating means in heaters of electric heaters
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24H—FLUID HEATERS, e.g. WATER OR AIR HEATERS, HAVING HEAT-GENERATING MEANS, e.g. HEAT PUMPS, IN GENERAL
  • F24H9/00—Details
  • F24H9/12—Arrangements for connecting heaters to circulation pipes
  • F24H9/13—Arrangements for connecting heaters to circulation pipes for water heaters
  • F24H9/133—Storage heaters
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24D—DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR
  • F24D12/00—Other central heating systems
  • F24D12/02—Other central heating systems having more than one heat source
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24D—DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR
  • F24D2200/00—Heat sources or energy sources
  • F24D2200/04—Gas or oil fired boiler
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24D—DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR
  • F24D2200/00—Heat sources or energy sources
  • F24D2200/06—Solid fuel fired boiler
  • F24D2200/062—Coal fired boilers
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24D—DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR
  • F24D2200/00—Heat sources or energy sources
  • F24D2200/06—Solid fuel fired boiler
  • F24D2200/065—Wood fired boilers
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24D—DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR
  • F24D2200/00—Heat sources or energy sources
  • F24D2200/08—Electric heater
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24D—DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR
  • F24D2200/00—Heat sources or energy sources
  • F24D2200/12—Heat pump
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24D—DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR
  • F24D2200/00—Heat sources or energy sources
  • F24D2200/14—Solar energy
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F24—HEATING; RANGES; VENTILATING
  • F24D—DOMESTIC- OR SPACE-HEATING SYSTEMS, e.g. CENTRAL HEATING SYSTEMS; DOMESTIC HOT-WATER SUPPLY SYSTEMS; ELEMENTS OR COMPONENTS THEREFOR
  • F24D3/00—Hot-water central heating systems
  • F24D3/12—Tube and panel arrangements for ceiling, wall, or underfloor heating
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
  • Y02B10/00—Integration of renewable energy sources in buildings
  • Y02B10/20—Solar thermal
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
  • Y02B10/00—Integration of renewable energy sources in buildings
  • Y02B10/70—Hybrid systems, e.g. uninterruptible or back-up power supplies integrating renewable energies
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
  • Y02B30/00—Energy efficient heating, ventilation or air conditioning [HVAC]
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
  • Y02B30/00—Energy efficient heating, ventilation or air conditioning [HVAC]
  • Y02B30/12—Hot water central heating systems using heat pumps

Definitions

• This invention relates to a modified thermal store adapted to provide both domestic hot water and water for space heating circuits.
• the invention further relates to an integrated domestic hot water and space heating system (hereinafter referred to as a modified thermal store installation) built around such a modified thermal store.
• Conventional thermal stores operate by utilising the ability of water to store large amounts of thermal energy.
• the basic principle is to input heat to an insulated reservoir of water from one or more heat sources, with the thermal energy then being stored within the reservoir until required. Heat is withdrawn from the store indirectly via heat exchanger coils when required for domestic hot water and space heating circuits.
• thermal store has the potential to deliver a highly energy efficient domestic hot water and space heating system.
• conventional thermal stores have thus far failed to fulfil that potential.
• a principal reason for this is that both conventional space heating circuits, and particularly domestic hot water systems, require relatively high water temperatures - generally around 60 °C.
• the indirect exchange of heat via heat exchange coils in conventional thermal stores means that the heat source(s) must produce higher temperatures - up to around 80 °C - in the primary water (the water heated directly by the heat source) in order to take account of inevitable wastage of energy during the heat transfer to the secondary water (the water withdrawn for domestic hot water and space heating circuits). This factor effectively cancels out the potential increase in energy efficiency promised by conventional thermal store technology.
• the high temperature to which the primary water must be heated effectively rules out the use of renewable energy sources such as solar power, and so conventional thermal stores have tended to rely on inefficient and environmentally damaging heat sources such as oil- or gas-fired boilers. Even if used with more efficient condensing boilers, the high temperature of the primary water returned to the condensing boiler prevents the boiler from operating in the high efficiency condensing mode. Heating the primary water to around 80 °C also makes conventional thermal stores unsuitable for use with low energy space heating systems such as underfloor heating, which only require temperatures of around 45 °C.
• the present invention seeks to provide a modified thermal store adapted to deliver both domestic hot water, and water for space heating circuits - and in particular for low energy heating circuits such as underfloor heating.
• the present invention seeks also to provide an integrated domestic hot water and space heating system, hereinafter referred to as a modified thermal store installation, built around such a modified thermal store.
• the present invention further seeks to provide both a modified thermal store and a modified thermal store installation having greatly enhanced energy efficiency properties, as compared to conventional thermal stores, and to minimise or eliminate other shortcomings of conventional systems, as described above.
• a modified thermal store for supplying domestic hot water and water for one or more space heating circuits, said modified thermal store comprising:
• first compartment having a first primary water inlet for receiving heated primary water from a heat source, and an inner chamber forming a reservoir for domestic hot water, said inner chamber being enclosed within said first compartment and having a mains water inlet for receiving cold mains water and a hot water outlet for discharging domestic hot water;
• a second compartment forming a reservoir for water for one or more space heating circuits, said second compartment having a second primary water inlet for receiving heated primary water from a heat source, and a heating circuit outlet for directing said heated primary water to said one or more space heating circuits;
• the efficiency of the system is thus greatly increased by removing the need for indirect heat transfer.
• the arrangement of the modified thermal store of the present invention with the first compartment providing a reservoir for domestic hot water, and the second compartment providing a reservoir for space heating water allows these dual functions to be combined in a single unit.
• the return inlet and the return outlet are preferably spaced apart in the return flow channel, such that said return flow channel forms an internal low loss header.
• the low loss header configuration allows control of the flow of primary water from the first compartment to the second compartment through the return flow channel, and the flow of cooled primary water returned through the outlet to the heat source.
• the low loss header configuration ensures that residual heat remaining in the cooled primary water returning from the one or more heating circuits is retained in the primary water of the second compartment reservoir, before the cooled primary water is returned to the heat source.
• the modified thermal store is adapted such that the first and second primary water inlets are each adapted to receive heated primary water from the same main heat source.
• the main heat source is preferably a heat pump, and most preferably an air source heat pump, though a ground source heat pump may alternatively be used.
• the modified thermal store preferably further comprises an insulated housing divided into said first and second compartments. More preferably, the - A -
• the first compartment is located vertically above the second compartment, with the first and second compartments most preferably being divided by a shared wall.
• the housing will generally be formed as a cylinder, though other configurations may also be employed.
• the modified thermal store preferably further comprises a valve, preferably a one-way ball valve, in communication with each of the first and second compartments, said valve being adapted to open upon the temperature of the primary water in the second compartment exceeding the temperature of the primary water in the first compartment.
• the second compartment acts a buffer reservoir for the first compartment, to 'top up' the first compartment with heat as required, in addition to performing its function as a reservoir for space heating circuits. This feature is particularly desirable where the second compartment is adapted to receive heat from an additional heat source.
• the return flow channel and/or the valve may desirably be mounted in the shared wall of the first and second compartments, thereby to interconnect the first and second compartments.
• the second compartment may desirably be adapted to receive heat from an additional heat source.
• the second compartment is provided with a heat exchange coil mounted therewithin and having an inlet for receiving heated water from an additional heat source and an outlet to return cooled water to said additional heat source.
• the additional heat source preferably utilises solar energy, and most preferably comprises one or more solar thermal collectors.
• the first compartment may desirably also be adapted to receive heat from one or more auxiliary heat sources, in addition to the main heat source.
• the first compartment further comprises at least one further primary water inlet for receiving heated primary water from one or more auxiliary heat sources.
• the auxiliary heat source may be an oil- or gas-fired boiler, an electrically-powered boiler, or a coal- or wood-burning stove; preferably the auxiliary heat source is an electrically-powered boiler.
• the or each primary water inlet of the first compartment is preferably provided with a flow director to direct the flow of heated primary water therein so as to enable maximum heat transfer to the inner chamber.
• the or each flow director is adapted to direct the flow of heated primary water in the first compartment so as to spiral around the inner chamber, thereby to enable maximum heat transfer thereto.
• the direction of the heated primary water around the inner chamber in this way further increases the energy efficiency of the modified thermal store of the present invention, as compared to conventional arrangements utilising heat exchange coils.
• the first compartment may desirably further comprise a desuperheater inlet for receiving heated water recovered from a desuperheater associated with a heat source - usually the main heat source.
• the desuperheater inlet is preferably arranged to feed directly into the inner chamber, whilst the hot water outlet is preferably adapted for returning water to the desuperheater.
• the desuperheater arrangement is utilised to recover potentially wasted heat from a heat source, and is most relevant where the main heat source is a heat pump.
• the inner chamber further preferably further comprises a pressure release valve.
• the second compartment preferably further comprises a flow regulator adapted to regulate the flow of heated primary water through the heating circuit outlet.
• a flow regulator adapted to regulate the flow of heated primary water through the heating circuit outlet.
• the need for such a flow regulator arises in particular where the main heat source is a heat pump and the heating circuit outlet is arranged to feed heated water to a low energy heating circuit, such as an underfloor heating circuit.
• the typical output flow of a heat pump is 40 litres of heated primary water per minute, whereas the typical requirement for an underfloor heating or low energy radiator circuit is less than 20 litres per minute, and can be as low as 5 litres per minute. Higher flow rates through such low energy heating circuits result in the temperature of the water returned to the heat pump being too high, leading to wasted thermal energy and cycling of the heat pump as described above, leading to the heat pump operating at below optimum efficiency.
• the flow regulator in combination with the low loss header configuration of the return flow channel, thus enables enhanced energy efficiency by minimising such energy wastage.
• the flow regulator also ensures that heated primary water entering the second compartment via the second primary water inlet flows into the second compartment reservoir as well as into the heating circuit outlet, thus enabling the second compartment to fulfil its role as a buffer reservoir for the first compartment, as well as its role as a reservoir for the heating circuit.
• the heating circuit outlet and the second primary water inlet are preferably located adjacent one another, and each in communication with the flow regulator.
• the flow regulator itself preferably comprises a channel fed by said second primary water inlet and arranged to direct a pre-determined proportion of heated primary water flowing therethrough to the heating circuit outlet, and to direct the remainder of said heated primary water through said channel into the second compartment reservoir.
• the flow regulator may desirably be formed as an open- ended box section.
• each of the first and second compartments is preferably further provided with a thermistor to monitor the temperature of the primary water in each compartment.
• Each thermistor supplies temperature data to control means adapted to control the flow of heated primary water to the first and second compartments as required, with priority being given to the first compartment, so that heating of the domestic hot water supply takes precedence over heating of the water for space heating circuits.
• the first compartment preferably further comprises an immersion heater, to provide a 'top-up' heat source on occasions when the main and/or auxiliary and/or additional heat sources are inoperative or are operating below optimum performance.
• the scope of the present invention extends to include an integrated domestic hot water and space heating system built around such a modified thermal store, said integrated system being hereinafter referred to as a modified thermal store installation.
• a modified thermal store installation comprising:
• the main heat source is preferably a heat pump, and most preferably is an air source heat pump, though a ground source heat pump may alternatively be used.
• Air source heat pumps operate by extracting usable heat from the atmosphere. The energy output of an air source heat pump is typically three to four times the electrically energy input required to operate the pump, giving 4kW of heat for every 1 kW of electricity used.
• the air source heat pump therefore represents a highly energy efficient and environmentally benign alternative to conventional heat sources such as oil- and gas-fired boilers. Whilst ground source heat pumps also exhibit excellent energy efficiency and environmental properties, the high cost and inconvenience of installing ground source heat pumps tends to cancel out the benefits, making the air source heat pump much preferred as the main heat source for the present invention.
• the modified thermal store installation preferably further comprises a space heating circuit adapted to receive heated primary water from the heating circuit outlet, and to return cooled primary water to the return inlet.
• the space heating circuit is preferably a low energy space heating circuit, and most preferably is an underfloor heating circuit.
• the modified thermal store installation preferably further comprises a primary water inlet pipe arranged to deliver heated primary water from the main heat source to the first and second primary water inlets, said primary water inlet pipe having one or more flow valves therein to direct said heated primary water to the first or second primary water inlet, as required.
• the installation further comprises control means adapted to control the operation of said one or more flow valves. This is most conveniently achieved by adapting the control means to operate in response to data supplied by thermistors provided in the first and second compartments as hereinbefore described. In this way, a pre-determined temperature may be maintained in each of said first and second compartments.
• the control means is preferably adapted to bias the one or more flow valves so as normally to direct the flow of heated primary water to the first primary water inlet. Operation of the one or more flow valves so as to direct the flow of heated primary water to the second primary water inlet then occurs upon the temperature in the first compartment reaching a pre-determined value. In this way, precedence is given to heating of the domestic hot water supply, before heating of the water for space heating circuits.
• the control means is preferably further adapted to control the operation of the main heat source in response to data supplied to the control means by the thermistors.
• the modified thermal store installation preferably further comprises an additional heat source adapted to deliver heated water to an inlet of a heat exchange coil provided in the second compartment as hereinbefore described, and to receive cooled water from the outlet of said heat exchange coil.
• the additional heat source is preferably adapted to utilise solar energy, and most preferably comprises one or more solar thermal collectors.
• the additional heat source can be activated as and when required to increase the temperature of the primary water in the lower compartment to the desired temperature without the need to operate the main heat source.
• the additional heat source may desirably be controlled by its own control system and deactivated once the water in the lower compartment reaches the desired temperature.
• the modified thermal store installation may be configured such that additional heat source is constantly activated so as to input heat into the thermal store whenever external conditions permit operation of the additional heat source.
• the additional heat source acts also to heat the primary water in the first compartment, as well as the primary water in the second compartment.
• the modified thermal store installation may preferably further comprise an auxiliary heat source adapted to deliver heated primary water to the further primary water inlet of the first compartment, as hereinbefore described.
• the auxiliary heat source may be an oil- or gas-fired boiler, or a coal- or wood-burning stove, but is preferably an electrically powered boiler.
• the main heat source of the modified thermal store installation may desirably be provided with a desuperheater adapted to deliver heated water recovered from said main heat source to the desuperheater inlet of the first compartment, as hereinbefore described. The employment of a desuperheater is most relevant where the main heat source is a heat pump.
• the desuperheater is adapted to receive water returned from the hot water outlet of the first compartment.
• the modified thermal store installation further comprises a thermostatic mixing valve adapted to mix water from the hot water outlet with cold mains water, thereby to deliver domestic hot water at a pre- determined temperature.
• Figure 1 shows a cross-sectional side view of a preferred embodiment of modified thermal store according to a first aspect of the present invention
• Figures 2a to 2d show expanded views of features of the thermal store of Figure 1 ;
• Figure 3 shows a diagrammatic representation of a preferred embodiment of modified thermal store installation according to a second aspect of the present invention, utilising the modified thermal store of Figure 1.
• the modified thermal store 10 comprises a generally cylindrical housing 1 1 having an internal generally cylindrical tank 12 surrounded by insulation 13.
• the tank 12 is divided into a first compartment 14 and a second compartment 15.
• the first compartment 14 is located directly above the second compartment 15, the two compartments 14, 15 having a shared wall 16 therebetween.
• the first compartment 14 is adapted to supply domestic hot water, whilst the second compartment 15 is adapted to supply water to a low energy, underfloor heating circuit (not shown in Figure 1 ).
• the first compartment 14 has an inner chamber 17 enclosed therewithin, forming a reservoir for domestic hot water.
• the inner chamber 17 is defined by an internal generally cylindrical wall 18, and is adapted to be fed with cold mains water via a mains water inlet 19 and to discharge domestic hot water via a hot water outlet 21.
• the inner chamber 17 is arranged to be heated by means of primary water circulating in the first compartment 14.
• the primary water is heated by an air source heat pump (not shown in Figure 1 ) forming a main heat source for the thermal store 10, and then fed into the first compartment 14 via a first primary water inlet 22.
• An auxiliary primary water inlet 23 is also provided, to receive heated primary water from an auxiliary heat source (not shown) such as an electrically-powered boiler.
• the first and auxiliary primary water inlets 22, 23 are each provided with flow directors 24.
• the flow directors 24 act to direct the flow of heated primary water entering the first compartment 14 through the primary water inlets 22, 23 such that the primary water spirals around the internal wall 18 defining the inner chamber 17. This ensures optimum heat transfer from the primary water in the first compartment 14 to the secondary water in the inner chamber 17.
• the second compartment 15 forms a reservoir for water for a low energy underfloor heating circuit (not shown in Figure 1 ), and has a second primary water inlet 25, adapted to receive heated primary water from the air source heat pump (not shown in Figure 1 ) constituting the main heat source for the thermal store 10.
• the second primary water inlet 25 is located adjacent a heating circuit outlet 26 adapted to direct heated primary water a low energy underfloor heating circuit (not shown in Figure 1 ).
• Both the second primary water inlet 25 and the heating circuit outlet 26 are arranged to communicate with a flow regulator 27.
• the flow regulator 27 serves to ensure that only a pre-determined proportion of heated primary water being fed into the second compartment 15 through the second primary water inlet 25 flows out of the thermal store 10 through the heating circuit outlet 26, with the remainder of said heated primary water flowing into the second compartment reservoir 15.
• a return flow channel 28 is mounted in the shared wall 16, interconnecting the first and second compartments 14, 15.
• the return flow channel 28 permits the cooler water at the bottom of the first compartment 14 to sink into the second compartment 15.
• the return flow channel 28 also communicates with a return inlet 29 adapted to receive cooled primary water returning from the underfloor heating circuit (not shown in Figure 1 ) and a return outlet 31 adapted to return cooled primary water to the main heat source (not shown in Figure 1 ).
• the return inlet 29 is located below the return outlet 31 and slightly spaced therefrom so as to form an internal low loss header configuration. This allows the temperature of the cooled primary water being returned through the return outlet 31 to be controlled, so as to avoid unnecessary cycling of the main heat source.
• a one-way ball valve 32 is also mounted in the shared wall 16, interconnecting the first and second compartments 14, 15.
• the ball valve 32 is adapted to open upon the temperature of the primary water in the second compartment 15 exceeding the temperature of the primary water in the first compartment 14, thus allowing the warmer water from the second compartment 15 to rise into the first compartment 14.
• the ball valve 32 thus enables the second compartment 15 to function as a buffer for the first compartment 14.
• the second compartment 15 is also provided with a heat exchange coil 33 having an inlet 34 arranged to receive heated water from a solar thermal collector array (not shown in Figure 1 ) constituting an additional heat source for the thermals store 10, and an outlet 35 arranged to return cooled water to said additional heat source.
• a solar thermal collector array as an additional heat source, heat can be constantly input into the thermal store 10 whenever conditions permit, thus significantly reducing the amount of work required to be carried out by the main heat source to heat the domestic hot water and underfloor heating water to the desired temperature.
• the first compartment 14 is further provided with an immersion heater 36 to provide a 'top-up' heat source on occasions when the main, auxiliary and/or additional heat sources are inoperative or are operating below optimum performance.
• Each of the first and second chambers 14, 15 is provided with a thermistor 37, 38, respectively.
• each said thermistor 37, 38 is arranged to supply data to control means (not shown in Figure 1 ) adapted to control the flow of heated primary water from the main heat source to either the first or second primary water inlet 22, 25 as required.
• control means not shown in Figure 1
• the first compartment 14 is further provided with a desuperheater inlet 39 adapted to receive heated water recovered from a desuperheater (not shown in Figure 1 ) associated with the air source heat pump.
• the desuperheater inlet 39 is arranged to feed directly into the inner chamber 17, which is further provided with a pressure release valve 41.
• FIG. 2a shows the construction of the flow directors 24 in more detail.
• a flow director 24 is fitted to each of the first primary water inlet 22 (as shown in Figure 2a) and the auxiliary primary water inlet 23.
• the flow director 24 is a generally rectangular box section, disposed at 90° to the direction of flow of primary water entering through the first primary water inlet 22.
• the flow director 24 has a generally rectangular exit aperture 42 of smaller cross-sectional area than the inlet 22.
• Primary water entering through the inlet 22 is thus turned through 90° and caused to enter the first compartment 14 under increased pressure, thus enabling the water to be directed around the internal wall 18 defining the inner chamber 17 as described above.
• FIG. 2b this shows the construction of the return flow channel 28 in more detail.
• the cooled water returning from the underfloor heating circuit enters the return flow channel 28 through return inlet 29, which is located beneath, and spaced from the return outlet 31 , which directs cooled water back to the heat pump (not shown).
• the heat pump When the heat pump is operating, the cooled water returning through return inlet 29 is directed back to the heat pump through the return outlet 31.
• the heat pump is not operating - i.e. when the primary water in the first and second compartments 14, 15 is at or above the desired temperature - the cooler primary water at the bottom of the first compartment 14 circulates through the return flow channel into the second compartment 15.
• the second compartment 15 is now acting as a buffer, with the heating circuit outlet 26 drawing off heated primary water from the top of the second compartment 15.
• the heating circuit outlet 26 drawing off heated primary water from the top of the second compartment 15.
• This low loss header configuration enables the temperature of the water being returned to the heat pump through return outlet 31 to be controlled, thus minimising heat loss and further enhancing energy efficiency by minimising unnecessary cycling of the heat pump.
• the ball valve 32 comprises a ball 43 held within a valve housing 44 adapted normally to be located in an aperture (not shown) in the shared wall 16 dividing the first and second compartments 14, 15.
• the valve housing 44 is provided with tapered shoulders 45 in order to facilitate the location thereof in said aperture.
• the lower part of the valve 32 is formed as a pipe 46 of narrower diameter than the valve housing 44.
• the flow regulator 27 comprises a channel 47 formed as an open-ended box section, and having a generally rectangular discharge aperture 48.
• the second primary water inlet 25 and the heating circuit outlet 26 each communicate with the flow regulator channel 47, and are located adjacent one another. Heated primary water is fed from the heat pump to the second compartment 15 through the second primary water inlet 25, whereupon it enters the flow regulator channel 47.
• the water turns through 90° in order to flow along the channel 47, and is directed past the heating circuit outlet 26. Any water exiting through the heating circuit outlet 26 must turn through a further 90°, whilst water exiting through discharge aperture 48 need not.
• discharge aperture 48 has a larger cross-sectional area than heating circuit outlet 26. Accordingly, a greater volume of water flows through discharge aperture 48 into the second compartment 15 than through the heating circuit outlet 26 into the underfloor heating circuit (not shown). This maintains the supply of heated primary water to the second compartment 15 in order for the compartment to fulfil its purpose as a buffer, and enhances energy efficiency both by reducing the rate of flow of heated water through the underfloor heating circuit, and by maintaining a flow temperature of 40°C through the underfloor heating circuit, without waiting for the second compartment 15 to be reheated.
• FIG. 3 there is shown a preferred embodiment of modified thermal store installation, generally indicated 50, according to a second aspect of the present invention.
• the installation 50 is built around a modified thermal store 10 as describe above with reference to Figures 1 and 2a to 2d.
• An air source heat pump 51 is connected to the thermal store 10 to serve as the main heat source.
• a primary flow pump 52 delivers heated primary water from the heat pump 51 along a primary water inlet pipe 53 to first and second primary flow valves 54, 55, respectively.
• the first primary flow valve 54 is adapted to control the flow of primary water to the first compartment 14 through the first primary water inlet 22; whilst the second primary flow valve 55 is adapted to control the flow of primary water to the second compartment 15 through the second primary water inlet 25.
• the operation of the first and second primary flow valves 54, 55 is regulated by control means 56 in response to data supplied to the control means 56 by the first and second thermistors 37, 38.
• the control means 56 is programmed so as normally to open the first valve 54 to permit the flow of primary water into the first compartment 14, but to close the second valve 55 to prevent the flow of primary water into the second compartment 15. In this way, priority is given to the heating of domestic hot water over water for underfloor heating.
• the control means 56 closes the first valve 54 and opens the second valve 55, thus permitting the flow of primary water to the second compartment 15.
• control means 56 closes the second valve 55.
• the first and second valves 54, 55 then remain closed until there is a call for heat.
• the control means 56 is adapted also to control the operation of the heat pump 51 and the primary flow pump 52, in response to data supplied to the control means 56 by the first and second thermistors 37, 38; and to control the operation of a heating circuit pump 57 for the underfloor heating circuit 58 in response to data supplied to the control means 56 by a room thermostat (not shown).
• a solar thermal collector array 59 is also connected to the thermal store 10, to serve as an additional heat source.
• a flow pump 61 for the additional heat source circulates water through the array 59 to be heated, and delivers the heated water to the second compartment 15 of the thermal store 10 through the heat exchange coil inlet 34. Cooled water is subsequently returned to the array through the heat exchange coil outlet 35.
• the second thermistor 38 operates with a "dead band" of 10°C, whereas the sensor (not shown) for the solar thermal collector array 59 operates with a "dead band” of 3°C, thus giving the solar thermal collector array 59 a 7°C operating priority over the heat pump 51.
• One or more auxiliary heat sources may additionally be connected to the thermal store 10 via auxiliary primary water inlet 23 as described above.
• the heat pump 51 is additionally provided with a desuperheater arrangement comprising a desuperheater pump 62 and a desuperheater flow pipe 63 arranged to recover potentially wasted heat from the heat pump 51 and return it to the first compartment 14 via the desuperheater inlet 39.
• a return flow pipe 64 for the desuperheater is connected to the hot water outlet 21 of the thermal store 10.
• a thermostatic mixing valve 65 is also provided to connect the hot water outlet 21 of the thermal store with the mains cold water inlet 19, to ensure a safe, constant operating temperature of domestic hot water delivered through taps 66.
• the modified thermal store installation 50 is further provided with a drain 67 to empty the thermal store 10 when required, and an expansion vessel 68 to allow for thermal expansion of the primary water in the closed system.

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• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Thermal Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• Physics & Mathematics (AREA)
• Water Supply & Treatment (AREA)
• Life Sciences & Earth Sciences (AREA)
• Sustainable Development (AREA)
• Sustainable Energy (AREA)
• Steam Or Hot-Water Central Heating Systems (AREA)
• Heat-Pump Type And Storage Water Heaters (AREA)
• Thermotherapy And Cooling Therapy Devices (AREA)

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• 2007
  • 2007-03-16 GB GBGB0705082.6A patent/GB0705082D0/en not_active Ceased
• 2008
  • 2008-03-17 WO PCT/GB2008/050188 patent/WO2008114051A2/en active Application Filing
  • 2008-03-17 EP EP08719033A patent/EP2132492A2/de not_active Withdrawn

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