GB2509354A

GB2509354A - Apparatus to heat domestic hot water and water for a space heating system

Info

Publication number: GB2509354A
Application number: GB1317513.8A
Authority: GB
Inventors: Houghton A Gledhill
Original assignee: LOBILS Ltd
Current assignee: LOBILS Ltd
Priority date: 2012-10-05
Filing date: 2013-10-03
Publication date: 2014-07-02
Also published as: GB201317513D0

Abstract

The apparatus comprises a thermal store such as two tanks (12,14, figure 1), a combination boiler 31, an additional energy source 6 and a controller 19. The thermal store and combination boiler are each arranged to selectively provide hot water for a domestic hot water (DHW) system 32 or for a space heating system 33,34. The controller allows control of the thermal store and energy source to provide DHW and hot water for the heating system. In a first aspect the energy source is a non-fossil fuel energy source such as a heat pump, wind or solar power and the controller automatically controls the thermal store and combination boiler. In a second aspect the thermal store utilises a phase change material and the controller permits user interaction to control operation. In a third aspect the thermal store and energy source are mounted externally of the premises. A method of forming a hybrid heating apparatus is also claimed. The apparatus permits use of the additional energy source to heat the thermal store such that the thermal store is used to meet DHW or space heating demand where possible with the combination boiler meeting any shortfall.

Description

Apparatus for the provision of hot water and/or heating The invention to which this application relates is apparatus for the use in the provision of heating and/or hot water for premises and typically, but not necessary exclusively, a domestic premises, and is particularly directed at installations which include combination boilers.

The provision of heating apparatus in premises is well known and, conventionally, this is provided in the form of apparatus, such as a combination boiler, in which there is provided a body of water, which is heated by a energy source. Upon demand, either by the opening of one or more taps to request hot water and/or the operation of a connected central heating system in the premises, the water which is heated by the energy source is drawn from the heating apparatus to provide a heating and/or hot water provision.

The heating of the water in the combination boiler has conventionally been achieved by the provision of an electric, oil, or gas fuelled heater which is placed in the body of water or through which the water passes. More recently, as environmental concerns have increased with regard to the use of fossil fuels, and also as technology has developed, a range of new energy sources have been identified such as air source heat pumps, ground source heat pumps, solar panels, wind turbines, for example. Any one or combination of these energy sources can be used to provide a heating effect to a body of water although there are often problems which are specific to the type of energy source used and their operation. Such problems can include an inconsistency of availability of fuel and hence heating due to climatic or environmental conditions.

It is also known to provide thermal store apparatus which is particularly suited for relatively small domestic premises such as terraced houses with the thermal store typically having a 170 litre capacity and which is primarily used for generating instantaneous domestic hot water by means of an external plate heat exchanger. While suitable for relatively small premises the conventional thermal store apparatus does not have sufficient capacity for the supply of the required heated water to larger premises. For example, if the thermal store is heated directly by a energy source to an average temperature of 54 degrees Celsius then the hot water is delivered at an average temperature of 49 degrees Celsius when the mains water inlet temperature is 10 degrees Celsius. Thus the maximum and useful energy storage capacities of the thermal store are 17.73 kwh/m3 and 9.O4kWh/m3 respectively. Furthermore, the energy storage density cannot be increased by raising the temperature of the stored water because there are currently no heat pumps available which can deliver water at above 35 degrees Celsius at an acceptable coefficient of performance. This means that the relatively low energy storage densities which can be achieved using the conventional apparatus provide significant barriers to the possibility of instaffing this type of system in larger dwellings or in dwellings which have higher than normal hot water consumption.

A further problem which is experienced is that the available space within domestic premises is often very limited and therefore the introduction of additional energy source and heating apparatus which would further reduce the available space is unattractive and can be unattractive to such an extent that the advantages provided by the improved heating apparatus are disregarded. The applicant, in their patent GB2434638, identifies the possibility of placing a storage vessel and power generating means externally of a premises in one or more housings as a means of overcoming the problem of the space required to install such apparatus and that the available space in domestic premises can be extremely limited or simply not be available.

An aim of the present invention is to provide apparatus for use as part of a heating system which includes a combination boiler. A further aim is to provide the apparatus in a form to allow the same to be retrofitted to existing heating systems and/or be used as part of the installation of new heating systems, and for the same to be installed in a manner which allows the apparatus to be provided whilst minimising the impact on available space within the premises. A further aim is to provide improvements in order to aflow the capacity of the thermal store to be increased and thereby increase the possible uses of the same over a wider range of premises and installations.

Tn a first aspect of the invention there is provided heating apparatus for a premises, said apparatus including a thermal store connected to provide hot water and/or hot water for a heating system for the premises, at least one non-fossil fuel energy source connected to the thermal store, a combination boiler, control means to allow control of the operation of the thermal store and the at least one energy source, and combination boiler and wherein the said control means automatically controls the operation of the thermal store and combination boiler to provide hot water and/or hot water for the heating system from the thermal store and/or combination boiler to the premises.

Typically the thermal store and energy source are located externally of that part of the premises which is to be heated In one embodiment the thermal store is provided to be capable, when operated, of providing the majority of the hot water and water for the heating system required by the premises in "normal" operating and environmental conditions, such as when the external temperature is at or above 0 degrees Celsius. This means that in normal operation, the control means will preferably operate the thermal store to provide the hot water and water for the heating system so as to obtain the benefits of using the non fossil fuel energy source and the combination boiler is operated only when there is additional demand over and above the normal operating conditions and, as a result, the benefits of using the cheaper option of operating the thermal store and the energy source can be achieved the majority of the time.

Typically the said control means monitors via plurality of sensors the availability and/or supply of hot water and water for the heating system and if the supply of the same does not meet predetermined requirements, the control system can operate the combination boiler to assist in the provision of further hot water and water for the heating system to therefore meet the demand and, in effect, operate the apparatus as a hybrid heating system.

The control means may be provided partly externally with respect to that part which is required to control the operation of the energy source and the thermal store, with the remainder of the control means internally of the premises and including a user interface to allow user interaction with the control means.

In one embodiment the thermal store utilises phase change material to provide a heating effect on the water supplied therefrom.

In one embodiment the thermal store includes phase change material (PCM) therein and/or water to provide the heated water supply therefrom by either, or both of, calling off water from a body of water heated in the thermal store and/or passing water through the phase change material to heat the same prior to leaving the thermal store.

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Typically the inclusion of the phase change material increases the energy storage density of the said thermal store.

Tn one embodiment the phase change material is encapsulated and configured so as to allow the same to provide a heating effect efficiently within the thermal store.

Typically the phase change material has a rate of heat absorption and release which is relatively low compared to water due to its low thermal conductivity and the crystallization of the phase change material on the surface in contact with water at high discharge rates.

Typically the thermal store has a capacity of at least 100 litres of water and can produce hot water at 22-32kW rate, with a sufficient supply volume in order to allow the filling of at least one bath in the premises.

Typically the temperature of the heathg fluid is at least 6 degrees Celsius greater than the melting point of the phase change material in order to melt it and hence store energy in the phase change material as latent heat.

Typically, if the required maximum flow temperature of water supplied from the heat pump of the heating apparatus is to be 55 degrees Celsius, the melting temperature of the phase change material should be no greater than 48 degrees Celsius.

Typically the temperature of the cooling water in contact with the phase change material must be at least (3 degrees Celsius lower than the melting point of the phase change material in order to freeze it and recover the stored energy.

In one embodiment the phase change material is integrated Into a water store to form the thermal store. In an alternative embodiment a water store and a phase change material store are provided which, in combination, form the thermal store. In a yet further embodiment, only the water store is provided and used as the thermal store.

In one embodiment the majority of the energy is stored at around 48 degrees Celsius in the phase change material store and is released when the store temperature starts to drop below around 41 degree Celsius.

Tn one embodiment the system is particularly beneficial for use with thermal stores which operate at relatively high temperatures such as at 70-85 degrees Celsius and/or for use in relatively low discharge rate applications such as the provision of water for central heating.

Preferably the phase change material is provided such that utilisation of the energy storage capacity of the phase change material is over 90%.

In one embodiment heat is transferred to and from the phase change material via suitable heat exchangers.

Tn one embodiment the control means for the heating apparatus allows the adaptive operation of the same to allow the operation of the apparatus to be adapted to suit any, or any combination of the particular location at which the apparatus is to be installed; the size of the premises which is to be supplied by the heating apparatus, the one or more available energy sources for the apparatus and the heating apparatus operation can be adapted accordingly.

In one embodiment the apparatus control means is provided with sensors and software to allow the same to detect changes in parameters and/or react to input changes in parameters and thereby adapt the apparatus to operate in the most efficient manner with the parameters presented to it at that time.

In another embodiment the energy source and the phase change material are integrated to minimise or eliminate the use of intermediate heat exchangers.

Typically the energy source in connection with the therma' store is a non fossil fuel heat source, In one embodiment the energy source is any, or any combination, of an air source heat pump, a ground source heat pump, a micro Combined Heat and Power Q'VICHP) engine, one or more fuel cells, wind power and/or solar power.

Tn one embodiment, lithe energy source is a heat pump the refrigerant used in the heat pump can be cycled through a heat exchanger in a phase change material module and thereby eliminate the need for an intermediate plate heat exchanger to be used.

In another embodiment the phase change material can be integrated with a energy source in the form of solar thermal panels.

In another embodiment the energy source which is used can include a supplementary energy source, such as a micro heat pump to use water heated by a main heat pump as a s(i)urce to raise the temperature of stored water at the top of the store to a higher temperature.

In another embodiment a two stage heat pump can be used.

In another embodiment a chemical energy store is provided.

In one embodiment, when the thermal store comprises a phase change material store and a water store, heated water can be selected to be supplied from either or both of said stores at any given time. In one embodiment the heated water from both stores is combined in order to allow for the supply of hot water to said premises.

In one embodiment, the water from both the water store and the phase change material store can be provided, in combination, to provide the hot water and heating supply or, alternatively, at any given time, water may be supplied only from the water store, or from the phase change material store if it is detected that the temperature of the water from one store is sufficient and/or the temperature of the water in the other of the stores is too low to be used.

Tn one embodiment, the apparatus includes mixing means which allows the selective mixing of water from the water store and the phase change material store to provide the hot water supply.

In one embodiment, the water supplied from the heat pump, is selectively supplied to both the water store and the phase change material store. Typically, the decision as to whether to supply any, or a quantity, of water from the heat pump, to either or both of the water store or the phase change material store, can be adjusted, typically via a valve intermediate the heat pump and the water store and the phase change material store.

Typically, the phase change material store is supplied with an unheated water supply, typically from mains water.

Typically, the heat of water supplied from the phase change material store will be lower than the heat of the water supplied from the water store and a mixture of the same allows a water supply to be provided which is of a required temperature, and duration of temperature, to meet the premises demand.

In addition, when required, the heated water supplied from the thermal store can be supplemented by the provision of heated water from the combination boiler which can be operated in response to specific conditions such as an increased demand or extreme environmental conditions such as particularly cold weather, or failure of the thermal store apparatus.

In one embodiment the energy source used for the phase change material store is controlled to be operated using fuel when the said fuel is at it's lowest tariff in a given period of time such as if the energy source uses electricity, operating he the same when the electricity supply is operating on at an "off peak" tariff.

Tn one embodiment at least the thermal store is located within an insulated housing.

In one embodiment the external location of the apparatus is in the outside environment, and most typically the apparatus is attached to or positioned adjacent to an external surface of the premises. In another embodiment the external location of the apparatus is in a part of the premises which is not heated, such as, for example, a car garage or shed.

In one embodiment, the control means to allow operation and communication between the at least one energy source and the thermal store, are located externally while the control means to allow user interaction with and control of operation of the apparatus, are located internally of the premises.

Typically, in operation of the apparatus, the energy source and thermal store provide up to 90% of the hot water and up to 90% of the water required for the central heating.

Typically the combination boiler system is located internally of the premises and said combination boiler uses an energy source fuelled by oil, electricity or gas.

The present invention therefore provides a hybrid heating apparatus and is provided in a form which allows a conventional single energy source apparatus which includes a combination boiler to be adapted into a hybrid apparatus which allows the selective use of two or more energy sources, at least one of which is more environmentally friendly, whilst ensuring that the available space in the premises to which the additional apparatus is fitted is not significantly reduced.

In one embodiment the thermal store includes first and second, interconnected, fluid storage vessels to allow the stored fluid to pass between the vessels and also be passed to provide hot water and or heated water for the heating system in response to user interaction with control means. Typically the thermal store acts as a buffer vessel for the energy source.

Typically the thermal store and control means therefore are located and connected in factory conditions and the housing formed there around such that the housing, with the apparatus located therein is provided as an integral unit to the location for installation at which the same is physically located and then connected for operation at the premises.

The use of a directly heated thermal store rather than an indirectly heated thermal store apparatus provides several advantages, one of which is that the thermal store does not require the provision of a heat exchanger between the thermal store and the heating pump and this improves the efficiency of operation of the system. A further advantage is that the use of a thermal store greatly reduces, if not eliminates, the possibility of legionnella forming and this, in turn, means that it is not necessary to frequently pasteurise the store.

In a further aspect of the invention there is provided heating apparatus for a premises said apparatus including a thermal store connected to provide hot water to, and/or connected to a heating system for, the premises, at least one energy source to allow a heating effect to be provided to the said thermal store, control means to allow control of the operation of the thermal store and the at least one energy source, and control means for user interaction with the heating apparatus to control the operation of the same, and a combination boiler and wherein the apparatus is controlled to allow the supply of heated water from the thermal store and /or combination boiler and the thermal store utilises phase change material to provide a heating effect on the water supplied therefrom.

In a yet further aspect of the invention there is provided heating apparatus for a premises, said apparatus including a thermal store connected to provide hot water and/or hot water for a heating system for the premises, at least one non-fossil fuel energy source connected to the thermal store, a combination boiler, control means to alft)w control of the operation of the thermal store and the at least one energy source, and combination boiler and wherein the thermal store and fuel energy source are mounted externally of the premises.

In a yet further aspect of the invention there is provided a method of forming a hybrid heating apparatus, said method comprising the steps of providing a combination boiler connected to supply hot water and water for a heating system for a premises; connecting a thermal store to the apparatus to provide hot water and water for the said heating system for the premises, connecting an energy source to allow a heating effect to be provided to the said thermal store, providing control means to allow control of the operation of the thermal store, the energy source and the combination boiler and wherein the control means are used to control the selective supply of hot water and/or water for the heating system from the thermal store and /or combination boiler.

Typically the thermal store and energy source are retrofitted to the heating system which includes the combination boiler.

In one embodiment the control means operates to supply hot water and water for the heating system from the thermal store in preference to from the combination boiler and when demand for hot water and/or water for the heating system cannot be met from thermal store alone, the combination boiler can be operated as the source in addition to, or alternatively to the thermal store.

Specific embodiments of the invention are now described with reference to the accompanying diagrams, wherein Figure 1 illustrates the externally mounted apparatus in accordance with a first embodiment of the invention; Figure 2 illustrates a system in accordance with an embodiment of the invention; Figure 3 illustrates the control system of the system shown in Figure 2; Figure 4 illustrates a user control panel for the system in accordance with one embodiment of the invention; Figure 5 illustrates graphically a typical Central Heating (space heating) flow temperature for a weather compensation function; Figure 6 illustrates graphically a typical Central Heating Load which can be supplied by a heat pump energy source; Figure 7 illustrates externally mounted apparatus with which phase change material can be implemented in accordance with an embodiment of the invention; Figure 8 illustrates schematically the heating apparatus in accordance with a further embodiment of the invention; and Figure 9 illustrates the heating apparatus in accordance with a yet further embodiment of the invention.

Referring firstly to Figure 1 there is illustrated a domestic premises 4 in which there is provided central or space heating and a hot water supply. The Figure illustrates the manner in which in accordance with the invention, part of the apparatus for heating the premises and providing the hot water supply is located externally of the premises and in this case is mounted on or adjacent to the external wall of the premises. The apparatus in this embodiment includes an energy source in the form of an air source heat pump 6 which can be of a conventional form and which is connected to a housing 8 in which there is provided a thermal store 10 in the form of twill storage vessels 12,14, shown in broken lines. The thermal storage vessels are located in a cavity 16 defined within the housing 8. Also located within the cavity are control means to allow the control of operation of the thermal storage apparatus and the interaction of the same with the energy source 6. The hatched portion 18 between the cavity and the outer walls of the housing, which are typically formed of sheet metal, is filled with insulation material in order to insulate the apparatus from the effects of the external environment temperature.

Turning now to Figure 2 there is shown a first embodiment of a system for the provision of heating and hot water and which incorporates the same components identified in Figure 1 and for which the same reference numerals have been used. The external wall 18 of the premises is shown in section. The apparatus comprises a power source 26 for the operation of the heat pump 6 and a pressure relief valve 28 is connected thereto. In the thermal store there is provided a cold water inlet I which allows cold water to be supplied to the thermal store, in this case from a connection within the premises 4, and the same is in communication with a plate heat exchanger 1 I which is also in communication with a PHF. modulating pump 22. The heated water from the heat exchanger then passes into the thermal store vessels 14,16. An air vent 20, expansion vessel 17 and pressure relief valve are also provided for safety purposes. The energy source 6 is connected to the thermal store via a heat pump circuit pump 24 which in turn is connected to a control unit 19, as is the energy source 6. The control unit 19 controls the operation of the thermal store and the energy source 6 as well as the central heating pump 13 and the plate heat exchanger 11, all of which are provided in the housing 8.

The control unit 19 is also connected to a combined boiler interface control means 9 which is located inside the premises 4 which is also connected to a power supply 30 and room thermostat 21. The combined boiler interface control means 9 is also connected to a combination boiler 31 located within the premises and this may have been provided as part of an existing heating system or may be installed at the same time as the installation of the externally mounted apparatus. In any case the combination boiler is provided with a central heating flow 38 in connection with the central heating flow 34 from the thermal store and with a central heating return 37 in connection with the central heating flow 34. A separate central heating return 33 is provided for the thermal store.

The combination boiler is also provided with a domestic hot water outlet 36 connected to the domestic hot water supply 32 for the premises and receives cold water from the inlet 35. As the combination boiler allows the heating of water and central heating boiler so this is available as a direct source of both hot water and central heating to the premises which is available to be called on to act alone to provide the heating and/or hot water or to provide the same in conjunction with hot water and/or central heating which may be provided from the thermal store and /or separate Phase Change Material store, if provided.

The apparatus provided in the housing 8 is typically assembled in factory conditions such that the same can be assembled and then provided to the location of use as an integral unit which is only required to be plumbed and electrically connected to the energy source externally of the premises and the combination boiler connections internally of the premises. This therefore means that firstly, the quality of the provision of the apparatus within the housing can be maintained and that the time of installation of the apparatus on site can be kept to a minimum.

Typically no modification of the existing combination boiler system, if already fitted, is required to allow the installation of the apparatus in the housing and, thereafter the combined operation of the apparatus.

Turning now to Figure 3 there is illustrated a diagram of the hydraulic circuit and controls of a system in accordance with one embodiment of the invention which are provided as part of the control means. A number of sensors are provided and these include sensor SI which is a mains cold water inlet temperature sensor and S2 which detects the hot water outlet temperature and these are used to detect the opening and closing of a hot water tap in the premises and hence the demand for hot water and for controlling the hot water flow temperature at a preset value. Sensor S3 and sensor S4 are lower and upper thermal store water temperature sensors and are used as thermostats to control the operation of the heat pump when it is in the store heating mode for domestic hot water.

Sensor S4 detects the water temperature near the top of the thermal store vessels is used in conjunction with sensor S3 as a thermostat to control the operation of the combination boiler to boost the hot water temperature when the hot water tap is open.

Sensor S5 is a thermostat which is used to prevent overheating of the water in the thermal store.

The sensor S6 is a central heating system flow temperature sensor which is used to control the central heating flow temperature in relation to the external temperature when the combination boiler is on and is used to provide a weather compensation function in the central heating mode for when the boiler is on by regulating the central heating flow temperature in relation to the external temperature measured by sensor 57.

Sensor S7 is an external temperature sensor which is used to detect the external temperature and act as a means of compensation for the weather conditions.

Sensors 58, S9 and SlO are heat pump flow temperature sensors, heat pump return temperature sensors and ambient temperature sensors respectively which are used to control the operation of the energy source 6 and to provide a weather compensation function for the central heating system.

The provision of the sensors and the control system provided via the control unit 9 provides the ability to utilise as much as possible the heat which is provided from the energy source 6 and to use this as the primary energy source and, where necessary, to use the combination boiler 31 as a secondary source of hot water for the supply of hot water and/or heating.

Figure 4 illustrate the control unit interface for use in the premises which includes means for allowing the user control of the demand for central heating and the room thermostat setting.

The unit includes a boost button 40 which allows the user to activate central heating for a fixed period of time, such as, for example when they have entered the premises and wish to warm the same rapidly. When this has been activated the combination boiler is switched on to boost the CH flow temperature. If the heat pump fails then the user can operate the heating and hot water system with the combination boiler by inserting an electronic key 42 in port 44 and this allows the combination boiler to operate in place of the external energy source for as long as required.

In operation of the system when the central heating (CH demand is active, the control unit 9 signals the controller 19 to switch on and the CH pump, 13, P3 circulates the pre-heated water from the primary thermal store 12 vessels to the radiators in the premises. The control Llnit 9 also signals controller 19 to switch on the energy source 6 and its circLlit pump, 14, P2.

When the CH demand is active, then if the external temperature measured by sensor, 57 is greater than a pre-set value, TBLR BOOST, then the heat pump controller regulates the flow temperature measured by sensor, S8 in relation to the external ambient temperature measured by the sensor, SlO using predefined weather compensation algorithms as iLlustrated in Figure 5.

If the external temperature measured by sensor, S7 is less than or equal to the pre-set value, TBLR_BOOST, then the heat pump controller regulates the heat pump flow temperature measured by sensor SB at its maximum setting, TFHP-JMAX, (typically 55 degrees Celsius) and the control unit 9 switches on the combination boiler 31 in space heating mode and regulates the CH flow temperature (above TFHP-MAX) measured by sensor, S6 in relation to the external ambient temperature measured by the sensor, S7 using the predefined weather compensation algorithms shown in Figure 5.

When either the room thermostat or the CH programmer stops calling for heating, the CH demand ceases if the combination boiler 31 is on, the control unit 9 switches off the same and the boiler pump after a preset pump overrun time. The control unit also signals the controller 19 to switch off the energy source and the pump 14, P2.

The domestic hot water is heated instantaneously by means of external plate heat exchanger 11 which transfers the heat from the preheated water stored in the thermal store 12 to the mains water flowing through it as shown in FigLire 3. In this embodiment the domestic hot water is available at all times and this function is independent of both the central heating and the primary thermal store heating functions. The hot water flow rate is regulated as before between 10 and 121 7mm.

When a hot water tap is opened, the temperature sensors, Si and S2, detect the flow rate and the controller 19 switches on the PHE pump Pt and modulates its speed to regulate the hot water oLitlet temperature at a pre-set value of 52±3 degrees Celsius. If the primary thermal store 12 temperature measured by the sensors S4 and S3 falls below the preset temperatures (about 30 degrees Celsius), the controller 19 switches the combination boiler 31 to standby mode to boost the domestic hot water outlet temperature if necessary. The controller 19 switches the combination boiler to off mode when the thermal store temperature measured by sensors S3 and S4 are above preset values (about 40 degrees Celsius and 45 degrees Celsius).

When a hot water tap is closed, the temperature sensors, Si and S2, detect this state and the controller 19 switches off the PHE pump, P1.

The heating of the thermal store inside the housing 8 is controlled by a hot water (HW) programmer in the control unit 9 and the thermal store temperature sensors, S3. Typically the heating of the thermal store has priority over central heating. Therefore if the thermal store heating demand is sensed when the CH pump, P3 is on, then the controller will switch off the CH pump, P3 until the thermal store heating cycle has been completed.

When the hot water programmer is calling for heating of the thermal store, store temperatures measured by the sensors S3 and S4 are less than about 48C and SOC respectively, the controller 19 will switch on the energy source 6 and its circuit pump, P2. When either the hot water programmer stops caffing for heating of the thermal store, or when the thermal store temperatures measured by the sensors, S3 and S4, are greater than about 53 degrees Celsius and 55 degrees Celsius, the controller 19 will switch off the energy source 6 and its pump, P2. The controller 19 continuously monitors the temperatures of the top reserve zone in the ITS (sensor S4) and the lower zone (sensor S3) if these temperatures fall below pre-set values, the controller will switch the combination boiler 31 to standby mode and when the system is in this mode, the combination boiler heats the domestic hot water.

The maximum flow temperature available from a typical air source heat pump is about 55 degrees Celsius. Therefore the heating load, which can be supplied by the heat pump, will depend upon the output of the radiators in the premises at 55 degrees Celsius flow temperature. The average monthly external temperatures are significantly above the design temperature for radiators and usually the radiators are oversized (10 -20%) to cope with intermittent heating etc. Taking these parameters, insulation measures implemented (eg double glazing, loft insulation) and the incidental gains into account, the heat pump operating at 55 degrees Celsius flow temperature can supply a significant proportion of the energy required for space heating without increasing the size of radiators as is illustrated in figure 6. In the system, the hot water heating has priority and therefore the energy source does not need to be sized for meeting simultaneous DHW and CII demands. I lowever, additional thermal power is required from the heat pump to cope with the intermittent heating modes and to achieve acceptable heating response times.

The present invention therefore provides a thermal store 12 which includes fufly integrated twin tanks for heating and instantaneous hot water and with a design and dimensions which allows for slim line external instaflation. The system allows the integration of more than one energy source to be selectively used in the form of, in the example given, an air source heat pump, and a combination boiler respectively, with user controls provided and which requires no modificatinn to boiler or energy source controls. This therefore provides a hybrid system with weather compensation and allows the user to be provided with a standby facility without requiring the user to switch to use the combination boiler and the associated relatively high cost energy unnecessarily.

Figure 7 illustrates apparatus similar that described previously with regard to Figures 1-6 and in this case the heating apparatus 52 for the premises 54 again provides space heating and a hot water supply.

An external energy source 56 is connected to a housing 58 in which there is provided a thermal store 60 in the form of twin storage vessels 62. The thermal storage vessels are located in a cavity 66 defined within the housing 68 along with control means 63 to allow the control of operation of the thermal storage apparatus and the interaction of the same with the energy source 56.

Also provided in conjunction with the thermal store 60 is phase change material 64 which is located in, or in association with, the thermal store 60 in order to increase the capacity of the apparatus to supply hot water for the hot water supply and/or heating system in the premises 54. This ability to increase the capacity by utilising phase change material allows the possible range of uses and installations of the apparatus in accordance with this invention to be significantly increased with respect to the apparatus currently available, whilst maintaining the advantages of being able to locate a large part of the apparatus externally of the premises to which the hot water and heating effect is to be provided.

Referring now to Figure 8 there is illustrated apparatus 72 in another embodiment which utilises phase change material as part of the same for providing hot water to the premises via a hot water supply 74 passing through the wall 76 of the premises to the interior 78 of the premises.

In the opposite direction there can be provided a cold water mains supply 80 which is supplied to a phase change material store 82 which is provided separately to but in communication with a thermal water store 84 and heat pump 86. Heated water is supplied from the heat pump 86 via pump 88 to a valve 90. The valve is provided to allow a selective flow of the water from the heat pump via branch 92 to the primary water store 84 and via branch 94 to the phase change material store 82. The quantities of water which are supplied to the respective stores, 82, 84 can be adjusted to suit particular operating conditions. Water from the thermal store 84 can be supplied, upon demand from the premises, via outlet 96 to the plate heat exchanger 98 and, from the phase change material store 82 via outlet 99 to the plate heat exchanger 98 and, in combination, from the plate heat exchanger 98, to the water supply 74.

Turning now to Figure 9 there is illustrated a further embodiment of the arrangement shown in Figure 8 in which, in this case, the primary water is circulated from the phase change material store 101 through the heat pump 102 and onto the thermal water store 103.

The water from the thermal store 103 is then fed through the plate heat exchanger 104 if there is a call for domestic hot water, or goes out 109 to the heating circuit 105 if there is a demand for heating. Both of these demands can be met simultaneously if required.

The hot water supply can be supplemented or replaced by passing the same through the combination boiler 106 if the hot water demand at an instant of time is greater than the heat pump 102 can satisfy to provide a supplemented or alternative hot water supply 107 to the taps in the premises.

Equally, the supply of heated water to the heating system 105 may be supplemented or replaced by heated water from the combination boiler via supply 111 again depending on the condition of the hot water supplied from the thermal store and heat pump at that time of demand.

This ability therefore provides a "hybrid" system in that the hot water supply is aimed to be provided primarily from an efficient energy source 102 but can be supplemented, or replaced, by heated water supplied from the conventionally fuelled combination boiler 106 but in any case the use of the combination boiler is reduced.

The system needs a purpose designed hybrid controller which takes information from a multiplicity of sensors, both in the system, the property and outside environment and thereby provides the user of the apparatus as herein described with a significant reduction in their fuel bill. Most utility suppliers supply an off-peak tariff (commonly called Economy 7) and these give seven hours of lower cost electricity through the night which is typically priced at or near the price of gas (in contrast to the on-peak cost of electricity which might be 2.5 times the gas cost). By using the off peak electricity to operate the heat pump and this achieves, for example, a Coefficient of Performance (C.O.P.) of 2.5, the running cost of the system would be significantly less than an equivalent gas system depending on the ratio of off-peak to on-peak elecfricity used. The operation of the heat pump at these times means that the PCM stores 64, 82, 101 in the respective systems are therefore only charged when an "off-peak" supply is available.

With a PCIvI store charged "off-peak" it is expected that more than S0% of the overall electricity used to supply the required heating and hot water in a 24 hour period of normal use in the premises wifl be at the "off-peak" price which can be achieved using the apparatus as herein described.

The provision of the phase change material store also means that the overall size of the apparatus is significantly reduced and thereby improves the ability to house the said apparatus in the housing externally of the premises.

Furthermore, the iosses of heat in the system are aiso greatly reduced. However, conventionally, problems would be experienced in that the supply of water, solely from the phase change material store, may not be possible at the required heat such that the hot water supply from the phase change material store alone, may not be high enough either initially and/or after prolonged use. This problem can be overcome in the current invention, by operating the phase change material store, in conjunction with the thermal store 60,84,103 in the respective systems which means that, if, for example, the phase change material store supplies hot water at 45°C at best, and the thermal store supplies hot water at a temperature of 55°C, then the respective supplies from the thermal store and the phase change material store can be mixed into a combined hot water supply 4 which is of a temperature of, for example, 52° which is acceptable for domestic use.

Typically, the thermal store which is provided, is relatively small, having, for example, a 80 -100 litre capacity so that the thermal store is used as a supplement to the phase change material store supply rather than being the only supply. Thus, the apparatus as illustrated in Figures 7-9 above, provides a means for supplying hot water at an acceptable level whilst still ensuring that the advantages of using the phase change material store can be obtained.

The apparatus can be provided at least partially as an integrated unit on site and hence little on site installation knowledge, with unique factory manufacturing techniques. The controls can be fully weather compensated with the supplementary requirements of the combination boiler also being controlled and hence a user specific system can be provided for the premises without compromising efficiency.

Claims

Claims 1. Heating apparatus for a premises, said apparatus including a thermal store connected to provide hot water and/or hot water for a heating system for the premises, at least one non-fossil fuel energy source connected to the thermal store, a combination boiler, control means to allow control of the operation of the thermal store and the at least one energy source, and combination boiler and wherein the said control means automatically controls the operation of the thermal store and combination boiler to provide hot water and/or hot water for the heating system from the thermal store and/or combination boiler to the premises.
2. Apparatus according to claim I wherein the thermal store and energy source are located externally of that part of the premises wrhich is to be heated.
3. Apparatus according to claim I wherein the thermal store and energy source have the capacity to provide the majority of the hot water and water for the heating system required by the premises.
4 Apparatus according to claim 3 wherein the thermal store can provide the majority of the hot water and water for the heating system in normal operating and environmental conditions when the external temperature is at or above 0 degrees Celsius.
S Apparatus according to claim I wherein the control means include a plurality of sensors to monitor the availability and/or supply of hot water and water for the heating system in the premises and selectively control the operation of the energy source, thermal store and combination boiler in response to the data received from the said sensors.
6 Apparatus according to claim I wherein the control means includes a user interface to allow user interaction with the control means within the premises.
7. Apparatus according to claim 1 wherein the thermal store includes the use of phase change material (PCM).
8. Apparatus according to claim 7 wherein the thermal store comprises phase change material integrated within a water store
9. Apparatus according to claim I wherein the thermal store comprises a water store and/or a store with phase change material therein.
10. Apparatus according to claim 9 wherein the heated water from both stores is combined in order to allow for the supply of hot water to said premises or water may be supplied only from the water store, or from the phase change material store if it is detected that the temperature of the water from one store is sufficient and/or the temperature of the water in the other of the stores is too low to be used.
11. Apparatus according to any of the preceding claims wherein the thermal store has a capacity of at least 100 litres of water and can produce hot water at a rate in the range of 22-32kW.
12. Apparatus according to claim I wherein the energy source and the thermal store are integrated.
13. Apparatus according to any of the preceding claims wherein the energy source for the thermal store is controlled to operate when the fuel used is at it's lowest tariff in a predetermined period of time.
14. Apparatus according to claim 1 wherein at least the thermal store is located within an insulated housing externally of the part of the premises which is to be heated.Apparatus according to claim I wherein the part of the control means to allow operation and communication between the at least one energy source and the thermal store are located externally while the part of the control means to allow control of operation of the heating apparatus, are located internally of the premises.16 Apparatus according to any of the preceding claims wherein the energy source used in conjunction with the thermal store is selected from any, or any combination, of an air source heat pump, a ground source heat pump, a micro Combined Heat and Power MCHP) engine, one or more fuel cells, wind power and/or solar power.17 Apparatus according to any of the preceding claims wherein the combination boiler is gas, oil or electrically fuelled.18. Heating apparatus for a premises said apparatus including a thermal store connected to provide hot water to, and/or connected to a heating system for, the premises, at least one energy source to allow a heating effect to be provided to the said thermal store, control means to allow control of the operation of the thermal store and the at least one energy source, and control means for user interaction with the heating apparatus to control the operation of the same, and a combination boiler and wherein the apparatus is controlled to allow the supply of heated water from the thermal store and /or combination boiler and the thermal store utilises phase change material to provide a heating effect on the water supplied there fr c) m.19 Heating apparatus for a premises, said apparatus including a thermal store connected to provide hot water and/or hot water for a heating system for the premises, at least one non-fossil fuel energy source connected to the thermal store, a combination boiler, control means to allow control of the operation of the thermal store and the at least one energy source, and combination boiler and wherein the thermal store and fuel energy source are mounted externally of the premises.A method of forming a hybrid heating apparatus, said method comprising the steps of providing a combination boiler connected to supply hot water and water for a heating system for a premises; connecting a thermal store to the apparatus to provide hot water and water for the said heating system for the premises, connecting an energy source to allow a heating effect to be provided to the said thermal store, providing control means to allow control of the operation of the thermal store, the energy source and the combination boiler and wherein the control means are used to control the selective supply of hot water and/or water for the heating system from the thermal store and /or combination boiler.21 A method according to claim 20 wherein the thermal store and energy source are retrofitted to a heating system which includes the combination boiler.22 A method according to claim 20 wherein the control means operates to supply hot water and water for the heating system from the thermal store in preference to from the combination boiler.23 A method according to claim 22 wherein when demand for hot water and/or water for the heating system cannot be met from the thermal store alone, the combination boiler is operated as a source of hot water and/or water for the heating system in addition, or alternatively, to the thermal store.24. A method according to claim 20 wherein the thermal store and/or energy source are located externally of that part of the premises which is to be heated by the heating system.A method according to claim 24 wherein the thermal store and/or the energy source are mounted externally of the premises adjacent the walls and/or roof.