WO2011048415A2

WO2011048415A2 - Heat transfer system

Info

Publication number: WO2011048415A2
Application number: PCT/GB2010/051766
Authority: WO
Inventors: Stuart William Dickson; Andrew James Garner
Original assignee: Stuart William Dickson; Andrew James Garner
Priority date: 2009-10-21
Filing date: 2010-10-20
Publication date: 2011-04-28
Also published as: GB0918438D0; WO2011048415A3

Abstract

A heat transfer system (1) for transferring heat between a target and a surrounding environment is described. The heat transfer system comprises a heat transfer panel (10) for transferring heat between a heat transfer fluid and the surrounding environment, a fluid pump (101) for circulating the heat transfer fluid and a heat pump (30) operable to pump heat between the target and the heat transfer fluid.

Description

Heat Transfer System

Technical Field The present invention relates to an improved heat transfer system and method for transferring heat between buildings and their surrounding environment. In particular, the present invention relates to a heat transfer system that can heat and/or cool targets such as domestic living spaces, water supplies and swimming pools. Background

Traditional heat transfer panels, in particular solar panels, are designed to collect radiated heat from the sun. Such solar panels are set up to pass the radiated heat through a glazed exterior surface, heating a circuiting pipe beneath. The pipe contains a fluid (usually water) that can be then pumped to heat a target. The glazed exterior surface of these solar panels is considered to be important as the glazing allows radiated heat to pass through to the pipe, whilst at the same time reducing the loss of heat from the pipe as a result of convection, for example, as a result of wind flow over the panel. The minimisation of conductive heat loss is further promoted by ensuring the region between the glazed exterior surface and the pipe is not thermally conductive. In particular, such solar panels may have the space between the glazed exterior surface and the pipe evacuated to minimise conductive heat loss. Glass is a preferred material for the exterior surface as it allows for good light transmission and it does not scratch or discolour, thereby increasing the durability of the solar panel, and also making cleaning easier. However, glass is a costly material to use. This is not only from the perspective of material cost, but also from the perspective of installation cost. For example, it can be difficult to safely position the glazed solar panel into place on a roof without cracking the glass. In addition, during installation, the solar panel need to be fixed to the roof in a manner that prevents warping of the solar panel, for example due to thermal expansion of the roof surface, as this may also cause the glass of the solar panel to crack. Thick glass may be used to increase the durability of the solar panel. However, this adds not only expense to the solar panel, but also significantly increases the weight of the solar panel. This can be particularly problematic for a roof that may not be able to bear heavy loads. This problem is further compounded by the fact that solar panels generally need to be produced as a regular sized unit which frequently accommodates only a small footprint on the surface of the roof, thereby resulting on an uneven load on the roof structure. Furthermore, if the solar panel occupies only a small area on the roof the full energy collecting potential of the roof structure will not be realised.

Another problem with such solar panels is that they only operate effectively when there is solar radiation. Their performance is very much hindered in heavy cloud cover and after sunset, especially if these panels are used during winter months when the amount of solar energy available is limited by the low solar angle and shorter daylight hours. In view of this, prior known solar panels tend not to be used in environments that are not consistently hot.

It is an object of the present invention to alleviate the above-mentioned, at least in part.

Summary of the invention

According to a first aspect of the present invention there is provided a heat transfer system for transferring heat between a target and a surrounding environment, the heat transfer system comprising a heat transfer panel for transferring heat between a heat transfer fluid and the surrounding environment, a fluid pump for circulating the heat transfer fluid and a heat pump operable to pump heat between the target and the heat transfer fluid. Advantageously, the use of a heat pump in conjunction with a heat transfer panel means that energy that is present in the surrounding environment can be effectively utilised, even though the absolute temperature of the surrounding environment may be lower than that of the target to be heated. This is because the heat pump is able to extract the energy in the heat transfer fluid and use this energy to heat the target. This lowers the temperature of the heat transfer fluid, which can then be returned to the heat transfer panel to pick up further energy from the surrounding environment.

The use of a heat pump can therefore also reduce the stagnation temperature that would otherwise render the use of an unglazed heat transfer panel ineffective.

Advantageously, a panel used to transfer heat can maximise the surface area over which heat can be exchanged. The use of a panel is advantageous over solutions like finned heat exchange surfaces which, when exposed to an external environment, would be prone to trapping dirt, thereby requiring maintenance.

Furthermore, in the example where the heat transfer panel is fitted to buildings and the like, the panel can be used as part of the building shell, increasing the structural integrity of the building.

It will be understood that the used of the heat transfer system is particularly applicable to applications in which the surrounding environment is that external to a building (i.e. exposed to the weather) and the heat transfer system is operational to change the temperature differential between the external environment and a target, such as the space within the building and/or a hot water supply.

Preferably, the heat pump is a variable capacity heat pump.

Advantageously, a variable capacity heat pump can allow the heat transfer system to be operated with greater efficiency. For example, if energy is being collected by circulating heat transfer fluid via the heat transfer panel (and the heat transfer fluid being circulated is approaching the stagnation temperature), a variable capacity heat pump would enable an incremental increase in the energy collection rate. By running the heat pump at a low capacity, the system will be more efficient (i.e. use less electrical energy) than running the heat pump at full capacity with on/off thermostat control. Secondly, when using the heat pump to boost the stored water to a temperature suitable for applications such as space heating, a variable capacity heat pump will be more efficient by enabling small temperature increases when, say, the stored tank temperature is only 5°C lower than required.

Preferably, the heat transfer panel comprises a fluid channel for carrying a heat transfer fluid, an exterior surface exposed to the surrounding environment, and a thermally conductive material between the fluid channel and the exterior surface, thereby allowing heat conduction between the heat transfer fluid and the surrounding environment.

It will be understood that the exterior surface would itself typically also promote heat conduction, and generally the exterior surface would be part of the thermally conductive material. Advantageously, the use of a thermally conductive material between the fluid channel and the exterior surface means that heat can be efficiently conducted between the surrounding environment and the heat transfer fluid. It will be noted that this will also cause conductive heat loss, as prior known solar panels are set up specifically to avoid. However, surprisingly, the heat transfer system benefits from the effect of heat conduction, especially when little radiated heat exists in the surrounding environment - for example during heavy cloud cover, or during the winter.

In particular, the invention advantageously exploits the fact that there is plenty of heat energy that can be effectively utilised that is not necessary in the form of energy radiated from the sun.

As mentioned, this set up is particularly advantageous when the heat transfer panel is paired with the heat pump as the heat pump can raise the temperature differential between the heat transfer fluid and the surrounding environment, raising the rate at which heat can be transferred between a target and a surrounding environment. This benefits from having a panel promoting conductive heat transfer, as this allows heat to be transferred between the heat transfer fluid and the surrounding environment more rapidly than can be achieved through prior known heat transfer panels that are designed to prevent conductive heat loss.

Furthermore, this advantageously allows the heat pump to be connected directly to the heat transfer panel so that the temperature of the fluid in the panel can be reduced to the extent necessary to transfer required amount of energy from the environment to the fluid regardless of the air temperature and level of solar radiation. Additionally, connecting the heat pump directly to the heat transfer panel allows the system to utilise the heat pump more effectively - for example, in generating useful hot water that can then be stored in a storage tank. This is a more advantageous arrangement than a system in which the storage tank is directly connected to the energy collection panels, and then a heat pump is used to boost the temperature of the water of the storage tank if it isn't high enough.

Therefore, it is preferable for the fluid pump to be arranged to circulate the heat transfer fluid directly between the heat transfer panel and the heat pump.

Preferably, the heat transfer system comprises a first configuration in which the target is cooled, and a second configuration in which the target is heated. Preferably, the heat transfer system is arranged to dynamically switch between the first and second configurations.

Preferably, the heat transfer system has a first configuration in which the fluid pump is arranged to circulate the heat transfer fluid directly between the heat transfer panel and a cooling circuit of the heat pump, and a heating circuit of the heat pump is arranged to heat the target.

Preferably, the heat transfer system has a second configuration in which the fluid pump is arranged to circulate the heat transfer fluid directly between the heat transfer panel and a heating circuit of the heat pump, and a cooling circuit of the heat pump is arranged to cool the target.

It will be understood that the use of a heat transfer panel promoting conductive heat transfer is also advantageous because it allows the improved use of the heat transfer system in multiple configurations - not only to heat a target, but also to cool it. In particular, the heat transfer system can be dynamically configured to pump heat either from the surrounding environment towards the target (in which case, a cooling circuit of the heat pump would be connected to the heat transfer panel, and a heating circuit would be connected to the target), or visa versa (in which case, the cooling circuit of the heat pump would be connected to the target, and the heating circuit of the heat pump would be connected to the heat transfer panel). In the latter case, the heat transfer panel needs to be able to effectively dump heat to the surrounding environment, and so this is aided by the fact that the panel employs conductive heat transfer. Conversely, prior known solar panels are not suitable for dumping heat, and so cannot be effectively used to cool a target.

Preferably, the exterior surface of the heat transfer panel is corrugated. Advantageously, the corrugated exterior surface of the heat transfer panel can maximise the surface area over which heat transfer can occur. Additionally, the corrugation promotes the structural integrity of the heat transfer panel. As a result of this, the heat transfer panel has a high strength to weight ratio, and so can be made to be lighter than prior known heat transfer panels without sacrificing durability.

Preferably, the fluid channels are disposed within ridges formed by the corrugated exterior surface. Advantageously, disposing the fluid channels within the ridges makes efficient use of the space beneath the exterior surface that would otherwise be wasted. In addition, the surface area of the fluid channels that is placed into close proximity with the surrounding environment is increased, thereby promoting heat transfer.

Preferably, the exterior surface of the heat transfer panel is corrugated in accordance with the profile of a standard corrugated building panel. Advantageously, this can facilitate retrofitting of the heat transfer panel to an existing structure already employing corrugated panels - in particular corrugated roofing. In addition, the aesthetic appearance of the building can be maintained.

The heat transfer panel may comprise a plurality of mounting regions for fixing the heat transfer panel to a support structure. Preferably, the plurality of mounting regions are distributed across the heat transfer panel. Preferably, the mounting regions are apertures through which the heat transfer panel may be bolted to a support structure. Preferably, the mounting regions are distributed between the ridges of the corrugated exterior surface of the heat transfer panel, preferably between the fluid channels. The mounting regions may also be distributed at the periphery of the heat transfer panel.

Advantageously, the plurality of mounting regions allow the heat transfer panel to be firmly affixed to a support structure at multiple positions over its entire area, and not just along it periphery. This means that, for example, a greater number of struts of an underlying support structure can bear the load of the heat transfer panel. It will be understood that prior known solar panels generally only are fixable around their periphery due to the fragility of glazing and cannot have this advantage.

Preferably, the exterior surface of the heat transfer panel and/or the thermally conductive material is a metal, for example, steel, aluminium, or steel with a zinc-aluminium alloy coating.

Advantageously, metals have a high strength-to-weight ratio and are malleable and flexible, thereby increasing the ease at which the heat transfer panel can be installed, and also maximising its durability. Preferably, the thermally conductive material defines the fluid channels. Advantageously, this promotes heat transfer via the thermally conductive material to the heat transfer fluid, more so than if the material defining fluid channels were separate from the thermally conductive material.

Preferably, the exterior surface is defined by the thermally conductive material.

Advantageously, having the thermally conductive material define the exterior surface and/or the fluid channels simplifies the manufacture of the heat transfer panel.

Preferably, the heat transfer panel comprises a substantially uniform cross-sectional area. Advantageously, this means that the manufacture of the heat transfer panel can be simplified, especially if the heat transfer panel is made out of a uniform material such as a metal. In particular the heat transfer panels may be manufactured via the process of extrusion.

The substantially uniform cross sectional area may have a repeated pattern along its length. This can further simplify manufacture, and can also allowing multiple panels to be joined alongside one another in a modular fashion.

According to a second aspect of the present invention there is provided a heat transfer panel comprising a fluid channel for carrying a heat transfer fluid, the heat transfer fluid being for use in heating and/or cooling a target, an exterior surface exposed to a surrounding environment, and a thermally conductive material between the fluid channel and the exterior surface thereby allowing heat conduction between the heat transfer fluid and the surrounding environment.

According to a third aspect of the present invention there is provided a heat transfer panel unit comprising a fluid channel for carrying a heat transfer fluid, the heat transfer fluid being for use in heating and/or cooling a target, an attachment plate for attachment of the heat transfer panel unit to a building panel having an exterior surface exposed to a surrounding environment and a thermally conductive material between the fluid channel and the attachment plate thereby allowing heat conduction between the heat transfer fluid and the attachment plate.

Preferably, the attachment plate is shaped to complement an interior surface of the building panel. Advantageously, this maximises the contact between the attachment plate and the building panel and further promotes the heat conduction between the heat transfer fluid and the surrounding environment. Preferably, the building panel is a standard corrugated building panel. According to a fourth aspect of the present invention there is provided a heat transfer system comprising a plurality of fluid channels for carrying heat transfer fluid, a plurality of heat transfer components, each connected to at least one of the fluid channels, a plurality of valves each arranged to control of fluid flow within at least one of the fluid channels, and a control module, in controlling communication with the plurality of valves, the control module operable to dynamically control fluid flow within the fluid channels to control heat transfer between the plurality of heat transfer components.

Preferably, the control module is in controlling communication with at least one of the plurality of heat transfer components.

It will be understood that by controlling flow of the heat transfer fluid, the control module is able to control heat flow between the heat transfer components.

Preferably, at least one of the plurality of heat transfer components is a heat transfer panel exposed to an external environment. Preferably, the heat transfer panel is a heat transfer panel in accordance with the first, second and/or third aspect of the present invention.

Preferably, at least one of the plurality of heat transfer components is a heat pump. Advantageously, the heat pump can maximise the efficiency at which heat can be transferred between other heat transfer components.

Preferably, at least one of the plurality of heat transfer components is a fluid storage tank. The fluid storage tank may be insulated to prevent thermal leakage to its surrounding environment.

Preferably, at least one of the plurality of heat transfer components is a heating and/or cooling target. The heating and/or cooling target may comprise a HVAC system, a radiator system, a swimming pool, a ground source heating/cooling system and/or a water source heating/cooling system. Preferably, the control module comprises a plurality of sensors to detect the condition of an operating environment, and in response control fluid flow between the plurality of heat transfer components. Preferably, the control module is user programmable. Preferably, the operating environment comprises an external environment, subject to the effects of the weather. The control module may comprise or be in communication with at least one weather gauge.

Preferably, the control module comprises a database and is arranged to log information about the condition of the operating environment over time, and from the information in the database, control fluid flow between the plurality of heat transfer components.

Preferably, the control module is arranged to analyse periodic characteristics of the operating environment, and in response control the fluid flow between the plurality of heat transfer components for future periods.

Advantageously, this allows the control module to predict how best to control the heat flow between components based on past trends. For example, the control module could determine that after a particular time of day, the outside temperature drops significantly (as a result of sunset), and so can prime the operation of the heat transfer components to account for this, as necessary. This means that lag in the system can be reduced, and also the system can be made to work more efficiently.

For example, if the heat transfer system is set up to heat a room during a cold night, it could determine that the energy to do this could be best obtained during a specific hottest period during the course of a day, and activate the transfer of heat from the outside heat transfer panels, pumped via a heat pump, into a storage cylinder during this period. As the heat pump is being used during the hottest period of the day, its efficiency, in particular, its coefficient of performance (COP) is maximised.

It will be appreciated that the coefficient of performance (COP) of a heat pump is a function of the temperature difference between the heat source (e.g. the ambient air temperature), and a heat load (e.g. a hot water tank). As a consequence, the COP is generally lower when demand is the highest (i.e. during cold ambient conditions). Therefore the heat pump COP is maximised by collecting and storing surplus energy during the warmest period of the day. Thus, the control module to work more adaptively than one being solely controlled by a timer a result of the use of a database which logs periodic characteristics of an operating environment. By way of example, the heat transfer system can be made to respond to changes in the environment over the course of a season (e.g. as a result of the sun set or rising earlier or later each day) - which could not be accounted for by a system being controlled by a timer.

It will be understood each aspect of the present invention may comprise features from other aspects where the context allows.

Brief description of the drawings

Specific embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings in which:

Figure 1 schematically shows a heat transfer system according to a first embodiment of the present invention;

Figure 2 shows the heat transfer system of Figure 1 , configured in a 'winter' mode of operation;

Figure 3 shows the heat transfer system of Figure 1 , configured in a 'summer' mode of operation; Figure 4 shows the heat transfer system of Figure 1 , configured in a 'mid-season' mode of operation;

Figure 5 schematically shows a flow diagram representing the logical steps taken by a control module of the heat transfer system of Figure 1 ;

Figure 6 schematically shows a heat transfer system according to a second embodiment of the present invention;

Figure 7 shows the heat transfer system of Figure 6 configured in a 'summer' mode of operation; Figure 8 shows the heat transfer system of Figure 6 configured in another mode of operation in which heat transfer fluid is routed to a storage tank;

Figure 9 shows the heat transfer system of Figure 6 configured in yet another mode of operation in which heat transfer fluid from a storage tank is heated by a heat pump;

Figure 10 shows the heat transfer system of Figure 6 configured in yet another mode of operation in which a load is heated by boosting heat energy collected by heat transfer panels using a heat pump;

Figure 1 1 schematically shows a cross-sectional view of a first variant of a heat transfer panel of the heat transfer systems of the first and second embodiments of the present invention; Figure 12 shows the heat transfer panel of Figure 14 on top of which is mounted asphalt shingles;

Figure 13 shows the heat transfer panel of Figure 14, which is pressed with a pattern to simulate slate or tile roofing;

Figure 14 schematically shows a second variant of the heat transfer panel of the heat transfer systems of the first and second embodiments of the present invention;

Figure 15 shows the heat transfer panel of Figure 14, as viewed from section line A-A;

Figures 16(i), 16(ii) and 16(iii) each in turn schematically show third, fourth and fifth variants of the heat transfer panel of the heat transfer systems of the first and second embodiments of the present invention; Figure 17(i) shows a sixth variant of the heat transfer panel of the heat transfer systems of the first and second embodiments of the present invention;

Figures 17(ii) and 17(iii) schematically show cross-section views of the heat transfer panel of Figure 17(i);

Figure 18 shows a modification of the heat transfer panel according to the sixth variant shown in Figure 17(i); and Figure 19 shows how a heat transfer panel of the heat transfer systems of the first and second embodiments of the present invention may be fixed onto a roof structure. Specific embodiments of the present invention

Referring to Figure 1 there is shown a heat transfer system 1 according to a first embodiment of the present invention. The heat transfer system 1 comprises heat transfer panels 10 that are mounted onto the roof of a house in which the heat transfer system 1 operates. (In alternatives, the panels may also be mounted to the walls of a house). The heat transfer system 1 also comprises a storage tank 20, a first heat pump 30, a second heat pump 40, a hot water cylinder 50, a space heating system in the form of radiators 60 and a control module 70. These components of the heat transfer system 1 are interconnected via fluid channels to allow heat to be transferred between one component and another. Fluid channels, and the direction of flow of heat transfer fluid within the fluid channels is shown by thick arrow-headed lines. It will be understood that the heat transfer fluid is water, but in alternatives, other fluids such as water mixed with corrosion inhibitors and/or antifreeze may be used.

The storage tank 20 is divided into five compartments by four dividers, each divider comprising a tank valve 21 , 22, 23, 24.

Each of the first and second heat pumps 30, 40 comprise a cooling circuit and a heating circuit. During operation of the heat pumps 30, 40, fluid passing via the cooling circuit has heat energy pumped from the cooling circuit towards fluid passing via the heating circuit. Therefore, fluid passing through the cooling circuit is cooled, and fluid passing through the heating circuit is heated using the energy extracted from the cooled fluid.

The heat transfer system 1 also comprises a series of fluid pumps 101 , 102, 103, 104 and fluid valves 1 1 1 , 1 12, 1 13, 1 14 which are located between the heat transfer components within the course of the fluid channels. The pumps are used to pump fluid between the heat transfer components, and the valves are used to direct fluid flow. By controlling fluid flow, the heat transfer between components is also controlled. The valves are motorised valves. The control module 70 is connected to the first pump 101 , the second pump 102, the third pump 103, the fourth pump 104 and the first and second heat pumps as represented via a series of dashed lines. The control module 70 is also connected to the first valve 1 1 1 , second valve 1 12, the third valve 1 13 and the fourth valve 1 14, as well as the valves in the storage tank 21 , 22,23, 24 although this is not shown in Figure 1 for clarity.

The control module is also connected to, and receives inputs from a group of sensors indicated generally as reference numeral 80. The group of sensors 80 comprise a plurality of temperature sensors located at a number of locations throughout the heat transfer system to provide the control module 70 with feedback about the operating environment of the heat transfer system 1 as a whole. In particular, the temperature sensors are placed to provide feedback about the temperature of each of the rooms, the outside of the house, the temperature of the heat transfer fluid within different fluid channels, the level of solar radiation and also the status of the components of the heat transfer system 1 .

Reference may be made to a heat transfer system 1 a according to the second embodiment shown in Figures 6 to 10 below in which an example of the type and distribution of individual sensors making up the group of sensors 80 is given.

The control module 70 is further connected to a user interface 72, which receives inputs from a user to control the operation of the heat transfer system 1. The inputs allows the user to alter the settings of a number of programs that determine the operating mode of the heat transfer system 1 . However, generally, the control module 70 will control the operation of the heat transfer system in dependence on the operating environment of the heat transfer system 1 , as determined from the group of sensors 80. In particular, the control module 70 will control the activation of selected pumps 101 , 102, 103, 104, control the opening or closing of selected valves 1 1 1 , 1 12, 1 13, 1 14, 21 , 22, 23, 24 and also switch on or off the first and/or second heat pumps 30, 40 to control how the heat transfer system 1 operates. Figure 1 shows the heat transfer system 1 in one possible configuration in which the heat transfer system 1 is inactive. I.e. the fluid pumps 101 , 102, 103, 104 and heat pumps 30, 40 are not activated. Referring to Figure 2, the heat transfer system 1 of Figure 1 is shown in a configuration in which the heat energy obtained from a surrounding environment by the heat transfer panels 10 is used to heat the hot water cylinder 50 and provide space heating via the radiators 60 as part of a 'winter' mode of operation. The first and second heat pumps 30, 40 are activated, as are all of the fluid pumps 101 , 102, 103 and 104. The second valve 1 12 is open, and the rest of the valves 1 1 1 , 1 13, 1 14 and 1 15 are closed.

As can be seen in Figure 2, the heat transfer panels 10 are fluidly coupled via the first fluid pump 101 to the cooling circuit of the first heat pump 30. The first heat pump 30 and the first fluid pump 101 are activated, and so the fluid in the heat transfer panels 10 will be cooled as it passes through the cooling circuit of the heat pump 30. The ambient outside temperature is around 7 degrees Celsius, and so the temperature of the fluid in the heat transfer panels is also 7 degrees Celsius prior to passing via the cooling circuit of the first heat pump 30. After passing through the cooling circuit of the first heat pump 30, the removed heat energy will cause the temperature of the fluid to drop to 3 degrees Celsius. The cooled fluid can then be returned to the heat transfer panels 10 to be reheated by the ambient conditions back to an temperature of around 7 degrees Celsius. The heat energy that is removed by the cooling circuit of the first heat pump 30 is transferred to the heating circuit of the first heat pump 30.

The storage tank 20 is fluidly coupled via the second pump 102 (via the open valve 1 12) to the heating circuit of the first heat pump 30 and so the water in the storage tank 20 will be heated as it passes through the heating circuit from 15 degrees Celsius to 25 degrees Celsius. As can be seen in Figure 2, all of the tank valves 21 , 22, 23 and 24 are open allowing the full capacity of the storage tank 20 to be utilised.

The output from the storage tank 20 is also fluidly coupled to the third pump 103, which is passed via the cooling circuit of the second heat pump 40. This acts to cool the output temperature from the storage tank 20 from 15 degrees Celsius to 10 degrees Celsius, which is then passed back to the storage tank 20 to be 'reheated' by virtue of the first heat pump 30. The heat energy removed by the cooling circuit of the second heat pump 40 can therefore be used to heat the fluid circulating in the heating circuit of the second heat pump 40. Specifically, the fourth pump 104 acts to circulate the fluid between the heating circuit of the second heat pump 40, the hot water cylinder 50 and the radiators 60. The temperature of the output from the heating circuit is 50 degrees Celsius and the return temperature is 35 degrees Celsius. Thus, it can be seen that two heat pumps are used in tandem to collect the heat energy present under ambient temperatures (of around 7 degrees Celsius) and use this energy to provide heating temperatures of up to 50 degrees Celsius for the purpose of providing hot water and heating of a house. Referring to Figure 3, the heat transfer system 1 of Figure 1 is shown in a configuration in which the energy from the heat transfer panels 10 is used to heat the hot water cylinder 50 as part of a 'summer' mode of operation. Specifically, the first and second heat pumps 30, 40 are deactivated, as is the second and fourth fluid pumps 102, 104. The first fluid pump 101 and the third fluid pump 103 are activated. The second valve 1 12 is closed, and the rest of the valves 1 1 1 , 1 13, 1 14 and 1 15 are open.

In this mode of operation, the heat transfer panels 10 are connected via the first open valve 1 1 1 directly to the storage tank 20. In the storage tank 20, the tank valves 21 , 22, 23, 24 are all closed, and so the inlet into the storage tank 20 only fills the first of the five available compartments with the fluid from the heat transfer panels 10 at the temperature derived from the surroundings, which in this case is 48 degrees Celsius. The return temperature of the fluid from the storage tank is 40 degrees Celsius. The fluid coming out of the storage tank 20 is pumped by the first fluid pump 101 to the heat transfer panels 10 to be reheated. The fluid in this case still runs through the cooling circuit of the first heat pump 30, but as the first heat pump 30 is not activated, there is no cooling effect on the fluid passing through the cooling circuit (and so no heating effect in the heating circuit of the first heat pump 30).

The fluid coming out from the storage tank 20 is also pumped by the third pump 103 to the hot water cylinder 50. The fluid from the hot water cylinder 50 is also returned to the storage tank 20.

In this mode of operation, the heat pumps 30, 40 are deactivated as there is sufficient heat energy in the ambient external environment to provide heating for the hot water cylinder 50. The reduction in size of the storage tank means that the system 1 can be made to operate more efficiently, and for a shorter period of time. As the heating demand of the system 1 is limited to hot water only, only a small amount of heat energy needs to be stored by the system 1. This is achieved by using only the first compartment of the storage tank 20. As mentioned, the control module 70 is connected to storage tank valves 21 , 22, 23 24 and so can control the effective capacity of the storage tank 20.

Referring to Figure 4, the heat transfer system 1 of Figure 1 is shown in a configuration in which the energy from the heat transfer panels 10 is used to heat the hot water cylinder 50 and radiators 60 as part of a 'mid-season' mode of operation. Specifically, the first heat pump 30 is deactivated and the second heat pump 40 is activated. The first, third and fourth fluid pumps 101 , 103, 104 are activated, and the second fluid pump 102 is deactivated. The second, fourth and fifth valves 1 12, 1 14, 1 15 are closed, and the first and third valves 1 1 1 , 1 13 are open.

In this mode of operation, the heat transfer panels 10 are connected via the first open valve 1 1 1 directly to the storage tank 20. In the storage tank 20, the first and second tank valves 21 , 22 are controlled by the control module to open, and the third and fourth tank valves 23, 24 are controlled to close. Therefore, the inlet into the storage tank 20 fills the first three of the five available compartments with the fluid from the heat transfer panels 10 at the temperature derived from the surroundings, which in this case is 25 degrees Celsius. The return temperature of the fluid from the storage tank is 20 degrees Celsius. The fluid coming out of the storage tank 20 is pumped by the first fluid pump 101 to the heat transfer panels 10 to be reheated. As before, the fluid in this case still runs through the cooling circuit of the first heat pump 30, but as the first heat pump 30 is not activated, there is no cooling effect on the fluid passing through it.

The fluid coming out from the storage tank 20 is also pumped by the third pump 103 to the cooling circuit of the second activated heat pump 40. This cools the temperature of the fluid from 20 degrees Celsius to 10 degrees Celsius, and the cooler fluid outputted by the second heat pump's cooling circuit is returned to the storage tank 20 to be reheated by the heat transfer panels 10.

The heat energy extracted from the fluid in the storage tank 20 by the second heat pump 40 is used to heat the fluid in the heating circuit of the second heat pump 40. This fluid is pumped by the fourth fluid pump 104 to the hot water cylinder 50 and also the radiators 60 to provide space heating and hot water. In this mode of operation, only the second heat pump 40 needs to be activated. This is to provide a small boost to the heat energy that can be derived from the external environment so as to provide domestic heating and hot water. The effective storage capacity of the storage tank 20 is optimised and controlled in support.

As described with respect to Figures 2 to 4, the heat transfer system 1 has different modes of operation - i.e. winter, summer and mid-season modes. It will also be understood that the heat transfer system can switch between these and other modes of operation by controlling one or more actuators - i.e. by selecting the activation of one or more of the heat pumps, one or more of the fluid pumps and/or opening or closing one or more of the valves (including the tank valves). In particular, the control module 70 is in controlling communication with these actuators and so the control module 70 can select the optimal operating mode and dynamically control heat flow between the heat transfer components of the heat transfer system 1 .

Generally, when determining how to control the actuators of the heat transfer system, the control module takes into account any user-defined parameters set via the user interface 72, and also information about the heat transfer system 1 and its surrounding environment from the group of sensors 80. The control module 70 also uses prior logged information, stored in a control module database, as will be described.

Referring to Figure 5, there is shown a flow diagram representing the general logical steps taken by the control module 70 when controlling the operation of the heat transfer system 1 of Figure 1 .

Historic information about the surrounding environment 701 and current ambient conditions 703, for example regarding solar and ambient conditions are used in calculating a predicted heat collection profile 702 that is a function of day, time, ambient (e.g. outside temperature) conditions, solar radiation, and panel fluid temperature. Generally speaking, this is how much heat energy the system is likely to be able to collect from its surroundings based on past evidence.

This is combined with historic information about heating load demand 704 and the user- defined heating settings 706 to calculate a predicted load profile 705. Generally, the calculated predicted load profile 705 is how much energy a user is likely to want, and how it is to be used, based on past evidence, ambient (e.g. outside temperature) conditions, and current user settings.

The predicted heat load and energy collection profiles are combined with the current calculated storage tank energy 707 (derived from the storage volume and temperature) to determine the optimal operating mode 708 for the heat transfer system and the required energy storage in storage tank 20. The operating mode governs the operation of the heat pump/s 709, 710, fluid circulation pumps 71 1 , motorised valves 712, and storage volume 713.

Where the ambient conditions allow, the efficiency is optimised by not using a heat pump to boost the energy collection rate. If the predicted energy collection without a heat pump is not sufficient 702, then the first heat pump 30 is activated to boost the temperature in the storage tank 20 using the energy from the heat transfer panels 10 - as obtained from the external environment.

During winter, the storage volume will be maximised since there is a high heating demand. During warmer conditions, when heat load is lower, the effective storage volume can be reduced by closing one or more tank valves 21 , 22, 23, 24 in series as required to isolate compartments of the storage tank 20, thereby enabling the temperature of the stored fluid to increase more rapidly.

The controller continuously monitors the actual rate of energy collection and will modify the operating mode to optimise the energy collection and storage.

Thus the control module 70 is able to configure the heat transfer system 1 to collect heat energy from an external environment (using the series of heat pumps 30, 40 to boost the temperature when needed), and also dynamically change the amount of energy that can be stored so as to match the demand profile. Only activating the heat pumps when needed, and selecting the activation time and period can therefore maximise the energy efficiency of the heat transfer system 1 .

The system can be configured in a number of different modes of operation, and taking into consideration a number of situations as will be described. When the temperature of the heat transfer fluid from the heat transfer panels 10 is high enough, there is no need for the heat pumps to be utilised, and so the heat transfer fluids can be pumped directly to heat the required loads (c.f. "summer mode"). Similarly, if there is no heating demand (e.g. during the day) but the control module 70 determines that there will a heating demand be at a later time (e.g. during the night), then the heat transfer system 1 can be configured to collect energy during the day (where energy collection efficiency is at its maximum) and store it in the storage tank 20. As mentioned, the capacity of the storage tank 20 can be dynamically varied under control of the tank valves 21 , 22, 23, 24 to meet predicted demand.

Further modifications to the behaviour of the heat transfer system 1 as controlled by the control module 70 are possible. It will also be understood that the heat transfer system 1 may be realised using an alternative combination and arrangement of components than that shown in Figures 1 to 4. One example of an alternative arrangement is shown in respect of a second embodiment of the present invention, which will now be described with reference to Figures 6 to 10. It will be appreciated, however, that features of one embodiment may be combined with another embodiment where context allows.

Referring to Figure 6, there is shown a heat transfer system 1 a according to a second embodiment of the present invention. The heat transfer system 1 a comprises heat transfer panels 10a, a storage tank 20a, a heat pump 30a, a heating load 50a, a first fluid pump 101 a, a second fluid pump 102a, a first fluid valve 1 1 1 a, a second fluid valve 1 12a, a third fluid valve 1 13a, a fourth fluid valve 1 14a, a fifth fluid valve 1 15a, a sixth fluid valve 1 16a, a seventh fluid valve 1 17a, an eighth fluid valve 1 18a and a ninth fluid valve 1 19a. The heat transfer system 1 a of this second embodiment is different from the first embodiment in that it comprises only one heat pump 30a instead of two, and also the independent heating loads such as the hot water cylinder and radiators are not shown - instead there is a single heating load 50a. Furthermore, there are nine fluid valves in this second embodiment, whereas in the first embodiment there are only four. Also, in this heat transfer system 1 a, the storage tank 20a is shown as a single unit, without any subdivisions for the purposes of clarity. However it will be understood that, in alternatives, the storage tank 20a may be similar to that of the storage tank 20 of the first embodiment, in that it may be controlled to dynamically alter its effective capacity. Further features such as an air vent, and an expansion tank are also present in this second embodiment of the heat transfer system 1 a. The heat transfer system 1 a comprises a control module, but this is not shown in Figure 6. As with the previous embodiment, a group of sensors T1 , T2, T3, T4, T5, T-LOAD, F1 , F2, G1 , 11 are connected to the control module to allow the control module to obtain information about the condition of the heat transfer system 1 a as a whole, as well as the external environment. On receiving the information about the sensors, and in accordance with its programming, the control module is arranged to control the actuators (e.g. fluid pumps, heat pumps and fluid valves) of the heat transfer system 1 a as will be described with reference to Table 1 as follows:

G1 Solar radiation level (W/m²) Used in conjunction with T1 to

predict the rate of energy

collection

11* Heat pump current Calculating the power

consumption and hence

overall coefficient of

performance

TABLE 1

It will be understood that, in alternatives, some of the sensors, particularly those which are marked by an asterisk, in Table 1 may be used to initialise the heat transfer system, and/or be used for the purposes of data collection only, and so may be left out of an initialised heat transfer system 1 a.

As can be seen in Table 1 , the sensors are used by the control module to collect information about the expected heat energy demands of the heat transfer system, and also the expected heat energy provisioning in view of the operating conditions of the heat transfer system 1 a. In response to the information collected by the sensors, the control module taken certain logical steps to controls the actuators (such as the heat pump and the fluid pumps) to meet heat energy requirements. The steps taken by the control module are similar to that described with respect to Figure 5 of the first embodiment of the present invention, as so will not be described further here in the interests of brevity.

Figure 6 shows a mode of operation in which the heat transfer system 1 a is uses the heat pump 30a and heat transfer panels 10a to boost the temperature of the storage tank 20a.

In particular, the first valve 1 1 1 a is open allowing the activated first pump 101 a to pump the heat transfer fluid circulating in the roof-mounted panels 10a via the cooling circuit of the heat pump 30a. This extracts transfers the heat present in the heat transfer fluid to the fluid circulating in the heating circuit.

The fourth, fifth and sixth valves 1 14a, 1 15a, 1 16a are also open, allowing the activated second pump 102a to circulate the heat transfer fluid in the heating circuit of the heat pump 30a via the storage tank 20a, thereby raising the temperature of the storage tank 20a using the heat energy transferred from the heat transfer panels 10a. As can be seen in Figure 6, the second and eighth and ninth valves 1 12a, 1 18a, 1 19a are closed, isolating the heating circuits and the cooling circuits. The third and seventh valves 1 13a, 1 17a are also closed, isolating the heating circuit from the load 50a. As will be appreciated, this second embodiment of the heat transfer system 1 a may be reconfigured to operate in different ways than that shown in Figure 6.

Referring to Figure 7, the heat transfer system 1 a of Figure 6 is configured to operate in a 'summer mode' of operation in which the heat transfer panels 10a are used to heat the load 50a.

In particular the first fluid, fourth sixth and ninth fluid valves 1 1 1 a, 1 14a, 1 16a, 1 18a, 1 19a are closed and the second, third, fifth and seventh fluid valves 1 12a, 1 13a, 1 15a, 1 17a are open. The first fluid pump 101 a is activated and the second fluid pump 102a and the heat pump 30a is not activated.

Therefore, heat transfer fluid is pumped by the first pump 101 a through the heat transfer panels 10a via the second valve 1 12a, and the third valve 1 13a to the load 50a - for example, a hot water cylinder. From the load 50a, the fluid continues its passage via the seventh fluid valve back to the first pump 101 a.

The heat pump 30a is not activated and so there is no transfer of heat energy from the cooling circuit to the heating circuit. Therefore the second pump 102a - arranged to pump fluid via heating circuit of the heat pump 30a is not activated either. Also, the remaining closed series of valves fluidly decouple the storage tank 20a from the rest of the heat transfer components.

Such a mode of operation would typically be used by the control module in the summer where the predicted heat energy demand would be relatively low (e.g. no space heating required - only hot water), and the amount of heat energy in the ambient environment was predicted to be sufficient to meet the heat energy demand.

Referring to Figure 8, another mode of operation to the second embodiment of the heat transfer system 1 a is shown. This instance is similar to the situation shown in Figure 7, in that the heat pump 30a and the second fluid pump 102a are not activated. However, in Figure 8, the valves are configured to route the heat transfer fluid from the heat transfer panels 10a to the storage tank 20a instead of the load 50a. In this instance, the second, fourth, sixth, and eight fluid valves 1 12a, 1 14a, 1 16a, 1 18a are open and the remaining valves 1 1 1 a, 1 13a, 1 15a, 1 17a, 1 19a are closed. Such a mode of operation would also typically be used in the summer in a situation following the mode of operation shown in Figure 7. For example, after the temperature of the load (e.g. hot water cylinder) has been raised to a sufficient level for current use, the control module may determine that further heating of the load will be required at a later point in time (e.g. during the night time). At this later point in time, the control module may infer, from previously collected data, that it is unlikely that there will be sufficient heat energy obtainable from ambient conditions to supply the further heating demand. Thus, in anticipation of this, the control module can be arranged to collect and store the additional heat energy in the storage tank 20a during the day. The heat energy stored can be therefore later be utilised by circulating the heat transfer fluid between the storage tank 20a and the heating load 50a.

A further problem may arise in a situation where the temperature of the heat transfer fluid circulating between the storage tank 20a and the heating load 50a falls below a desired level. This eventuality can be dealt with by the heat transfer system 1 a in the way shown in Figure 9.

In Figure 9, the heat transfer system 1 a is configured to use the heat pump 30a to increase the temperature of the fluid passing to the heating load 50a above that of the heat transfer fluid stored in the storage tank 20a.

In this mode of operation of the heat transfer system 1 a, the first and second fluid pumps 101 a, 102a and the heat pump 30a are activated. The third, sixth, seventh, eighth and ninth fluid valves 1 13a, 1 16a, 1 17a, 1 18a, 1 19a are open whereas the first, second, fourth and fifth fluid valves 1 1 1 a, 1 12a, 1 14a, 1 15a are closed.

The heat transfer fluid from the storage tank 20a passes through the sixth and then eighth open valve 1 16a, 1 18a to the first fluid pump 101 a. The first fluid pump 101 a then pumps the fluid via the cooling circuit of the heat pump 30a through the ninth valve back to the storage tank 20a. The heat energy in this circulating fluid is extracted by the heat pump 30a and used to heat the heat transfer fluid circulating via the heating circuit of the heat pump 30a.

This is pumped by the second pump 102a though the heating circuit of the heat pump 30a via the open third valve 1 13a to the load 50a and then back again to the second pump 102a via the seventh valve 1 17a.

Therefore, two separate heat transfer fluid circuits are established, one circuit passing via the storage tank and heat pump's cooling circuit and the other circuit passing via the load and the heat pump's heating circuit.

In this example, the valves shut off circulation of the heat transfer fluid to the heat transfer panels 10a. Another mode of operation of the heat transfer system 1 a according to the second embodiment is shown with reference to Figure 10.

In this example, the fluid in the heat transfer panels 10a are circulated via the cooling circuit of the heat pump 30a, and the heat pumped to the heating circuit of the heat pump 30a is used to heat the load 50a.

In this mode of operation of the heat transfer system 1 a, the first and second fluid pumps 101 a, 102a and the heat pump 30a are activated. The first and third fluid valves 1 1 1 a, 1 13a are open whereas the second, fourth, fifth, sixth, seventh, eighth and ninth fluid valves 1 12a, 1 14a, 1 15a 1 16a, 1 17a, 1 18a, 1 19a are closed.

The heat transfer fluid from the heat transfer panels 10a passes through the first open valve 1 1 1 a to the first fluid pump 101 a. The first fluid pump 101 a then pumps the fluid via the cooling circuit of the heat pump 30a back to the heat transfer panels 10a.

The heat energy in this circulating fluid is extracted by the heat pump 30a and used to heat the heat transfer fluid circulating via the heating circuit of the heat pump 30a.

This is pumped by the second pump 102a though the heating circuit of the heat pump 30a via the open third valve 1 13a to the load 50a and then back again to the second pump 102a via the seventh valve 1 17a. Therefore, as with the example shown in Figure 9, this example has two separate heat transfer fluid circuits, one circuit passing via the heat transfer panels and heat pump's cooling circuit and the other circuit passing via the load and the heat pump's heating circuit.

In this example, the valves shut off circulation of the heat transfer fluid to the storage tank 20a.

Thus it can be seen that the second embodiment of the present invention, like the first embodiment, employs a network of heat transfer components that can be dynamically controlled, depending on the programming of a controlling control module, to utilise ambient heat to meet heating the heating demand of a load 50, 50a.

Whilst examples of a load so far have been expressed in the form of a space heating system (e.g. a set of radiators) and also a hot water cylinder, other loads may also be connected to the heat transfer systems 1 , 1 a instead, or in combination. For example, a swimming pool may be heated as a load of the heat transfer systems 1 , 1 a described. Under-floor heating may be used in conjunction with, or in the place of radiators for space heating. Ducted hot air heating systems may be used through the addition of a water-to-air heat exchanger or by substituting the heat pump with a water-to-air heat pump.

Multiple houses may be connected to a single centralised heat pump and storage system to form a district heating or cooling system.

The present invention has been so far described with the ambient conditions being used to meet the heating demand of a load, the heat energy from the exterior environment essentially being pumped into and retained by the heat transfer system. However, it will be appreciated that the present invention may also be used in reverse, to pump heat energy from within the system out to an exterior environment. In other words, the present invention may also be used not only to heat loads, but also to cool them.

By way of example, the heat transfer systems 1 , 1 a described above may be modified so that the heat transfer fluid circulating via a load may routed via the cooling circuit of a heat pump. This would cool the heat transfer fluid circulating via the load. The heat energy pumped away from this circulating heat transfer fluid could then be expelled to the external environment using the heat transfer panels. The principle of delaying the transfer of heat, as described above, is also applicable to this reversed mode of operation. In other words, whereas in the above described first and second embodiments, the storage tank 20, 20a was acting as a thermal store for heat collected during a relatively hot day, to be utilised during a relatively cool night, it can also be used as a thermal dump for unwanted heat during the day.

For example, during the cool night, the heat transfer system could cool a load such as a space cooling system (e.g. an air conditioning system) as well as cooling the heat transfer fluid in a storage tank. The energy removed from these components could be expelled to the external environment using the heat transfer panels as radiators. After this, during a hot day, the cooled water in the storage tank can then be used as a thermal dump for continued operation of the space cooling system. In addition, the heat pump can be used to maximise the amount of heat energy transferred between each component of the system. In particular, during the cooling cycle, the cooled fluid from the heat transfer panels can be further cooled by the cooling cycle of the heat pump, the heating circuit of which can be used to heat the fluid on route to the heat transfer panels.

In this case, the heat pump is run at night, potentially taking advantage of where demand on the electricity power grid is at its lowest (and so can be run at a lower cost, night-time electricity tariff). Each of the above described embodiments, and variants thereof make use of heat transfer panels 10, 10a. These act to collect or dissipate heat energy between the heat transfer system and its surrounding environment. These heat transfer panels will now be described in greater detail. Referring to Figure 1 1 , there is shown a cross-sectional view of one variant of a heat transfer panel 10 according to the present invention, and as used in the heat transfer systems 1 , 1 a as described above.

In this variant, the heat transfer panel 10 comprises a standard corrugated building panel 15 to which there is attached a plurality of heat transfer panel units 14. As can be seen in Figure 1 1 , the standard corrugated building panel 15 defines a series of ridges, and each heat transfer panel unit 14 is disposed within each ridge. Although only two ridges are shown, it will be understood that the additional ridges, with the same repeating pattern and each housing a heat transfer panel unit 14 will be present in a heat transfer panel 10. Each heat transfer panel unit 14 comprises two fluid channels 1 1 which are defined by tubes 12 running along the length of the heat transfer panel unit 14. The tubes 12 are integral with a curved attachment plate 13 that is shaped to match the contours of the standard corrugated building panel 15. As the attachment plate 13 is shaped to complement the building panel, the area of contact between them is maximised.

The heat transfer panel units 14 are bonded to one side of the standard corrugated building panel 15 using a thermally conductive adhesive. The other side of the standard corrugated building panel 15 forms an exterior surface 16 that is exposed to the surrounding environment.

The heat transfer panel units 14 and the standard corrugated building panel 15 are made of steel or aluminium, which are suitably strong and thermally conductive materials.

The heat transfer panel 10 comprises a plurality of mounting regions 17, disposed on the apex of the ridges. The positioning of the mounting region on the apex improves the water-tightness of the panel for when the panel is mounted upon a roof structure. However, in alternatives, for example, when the panel is mounted onto walls, the mounting regions can be between the ridges, and therefore also between adjacent heat transfer panel units 14. The mounting regions 17 allow the bolting of the heat transfer panel 10 to a support structure 18.

The mounting regions 17 are distributed across the heat transfer panel 10, and so the heat transfer panel 10 can be securely fastened at many locations to an underlying support structure. It will be noted that the heat transfer panel 10 can be fixed at multiple positions over its entire area, and not just along it periphery, as would be the case with standard (glazed) solar panels, thereby allowing for a more secure fixing to and load distribution over the underlying support structure 18.

The heat transfer panel units 14 have a uniform cross sectional area and so can be cut to the desired length. This facilitates retrofitting to a standard corrugated building panel 15 of any length. This also facilitates the manufacture of the heat transfer panel unit 14, which is created via the process of extrusion. The fluid channels 1 1 of the heat transfer panel units 14 are connected to one another to form a fluid channel circuit travelling underneath the surface of the heat transfer panel 10. Adjacent pipe ends are generally connected to one another to form this circuit. However, it will be understood that some of the fluid channels ends act as inlets and outlets to allow the heat transfer panel 10 to be connected to the rest of a heat transfer system 1 , 1 a.

In use, the heat transfer fluid, typically water, is pumped through the connected fluid channels 1 1. The arrangement of the heat transfer panel 10 is such that the thermal conduction between the heat transfer fluid and the surrounding environment is maximised, not only because of the large surface area presented by the panel to the surrounding environment, but also because of the thermally conductive materials present directly between the fluid channels 1 1 and the surrounding environment.

It will be appreciated that whilst prior known solar panels are set up to minimise conductive heat loss, the heat transfer panels of the present invention are arranged to benefit from the effect of maximised thermal conductivity. In particular, the heat transfer panel 10 can successfully operate when there is no solar radiation, for example during heavy cloud cover and after sunset. So long as the ambient temperature is warmer that the heat transfer fluid being heated, heat energy can be collected for the surrounding environment. As mentioned above, the heat transfer fluid can be made to be colder than the surrounding environment by pumping in via the cooling circuit of a heat pump.

In another example, the heat transfer panel 10 can also be effectively used where heat needs to be dissipated to the surrounding environment. For example, on a hot summer day, there may be a requirement to cool the interior of a house. If the target being cooled is run via the cooling circuit of the heat pump, then the fluid circulating in the heating circuit of the heat pump is heated. This would typically be piped to the heat transfer panels 10 where the heat energy could be dissipated, as the temperature of the fluid would be above that of the surrounding environment. Other advantages of the heat transfer panel 10 will also be appreciated. The arrangement allowing retrofitting of the heat transfer panel units 14 to a standard corrugated building panel 15 provides a solution that is more cost effective than that associated with prior known solar panels. Therefore, it is more practicable to utilise the entire energy transfer area of a roof, rather than a small part of it. This is further facilitated by the ability to cut each of the heat transfer panel units 14 to exactly the right length for a given application. This has the advantage of maximising the amount of energy that can be transferred between the heat transfer fluid and the surrounding environment potentially allowing enough energy to be collected in winter conditions for applications such as space heating.

In addition, this also facilitates the use of the heat transfer panels on other structures, such as walls, which enables the panels to pick up greater amount of radiant energy than a roof during the winter due to a low solar angle. Furthermore, conventional solar panels sit on top of a roof structure, and so can be visually obtrusive. The heat transfer panels 10 can instead be mounted on the underside of existing roofing structures incorporating a standard corrugated building panel 15. Furthermore, the exterior appearance of the panels can be modified as required without adversely affecting the operation of the heat transfer panels 10.

In further variants of the heat transfer panel 10, the heat transfer panel 10 may not necessarily have a separate heat transfer panel unit 14 that is retrofitted to a standard corrugated building panel 15, but instead is manufactured as a single unit wherein the heat transfer panel unit 14 and exterior surface are pre-joined to one another. In further variants, the heat transfer panel may be made of a single material, the exterior surface 16 and the tubes 12 forming the fluid channels being integral with one another.

Further variants of the heat transfer panels 10 are as follows. Figures 14 and 15 show a second variant of the heat transfer panel. In this second variant, each ridge of a standard corrugated building panel 15 incorporates a single fluid pipe. Figure 15 shows the heat transfer panel of Figure 14, as viewed from section line A-A. Figure 12 provides an illustrative example where asphalt shingles or roofing felt, can be mounted onto the corrugated building panel 15 to modify the appearance of the heat transfer panel of the second variant. Figure 13 provides an illustrative example where the building panel can be pressed with a pattern to simulate slate or tile roofing to modify the appearance of the heat transfer panel of the second variant in another way.

Figures 16(i), 16(ii) and 16(iii) each in turn schematically show third, fourth and fifth variants of the heat transfer panel. In each case, a first building panel is pressed against and bonded to a second building panel to define a plurality of fluid channels therebetween. In each case, the open ends are joined to one another to define a fluid circuit along the length of the panel.

Figure 17(i) shows a sixth variant of the heat transfer panel. The profile of each of the first and second building panels forming this sixth variant is altered to seal the open ends. Referring to Figure 17(ii) and 17(iii) the profile is also altered to incorporate a depression allowing for a flow return path every alternate fluid channel so as to form a fluid circuit. The very end fluid channels of this design incorporate an end closing plate integrated with an inlet or outlet to allow heat transfer fluid circuiting the panel to also flow via a heat transfer system. Figure 18 shows a modification of the sixth variant shown in Figure 17(i) in which the open ends, where the end closing plates are fitted, are not needed. This is by virtue of an altered profile of the first and second building panels, which is then integrated with an inlet or outlet. Figure 19 shows how the heat transfer panels 10 described above can be fixed onto a roof structure. The modularity of the heat transfer panels 10 according to the present invention will be appreciated in view of Figure 19. Multiple panels can be joined to one another by overlapping the end ridges from adjacent panels. Mounting regions can be located at these end ridges as these end regions do not house water channels. In addition, a central ridge also does not contain a water channel and so a bolt can be used to affix each panel to an underlying support structure.

The overlapping of multiple panels creates a continuous barrier suitable for shielding the underlying roof support structure from the surrounding environment, thereby allowing the heat transfer panels 10 to act as a weatherproof roofing material.

Claims

1 . A heat transfer system for transferring heat between a target and a surrounding environment, the heat transfer system comprising:

a heat transfer panel for transferring heat between a heat transfer fluid and the surrounding environment;

a fluid pump for circulating the heat transfer fluid; and

a heat pump operable to pump heat between the target and the heat transfer fluid.

2. A heat transfer system according to claim 1 , further comprising a first configuration in which the target is cooled, and a second configuration in which the target is heated, the heat transfer system being arranged to dynamically switch between the first and second configurations.

3. A heat transfer system according to claim 1 or claim 2, wherein the heat transfer panel comprises a fluid channel for carrying a heat transfer fluid, an exterior surface exposed to the surrounding environment, and a thermally conductive material between the fluid channel and the exterior surface, thereby allowing heat conduction between the heat transfer fluid and the surrounding environment.

4. A heat transfer system according to claim 3, wherein the exterior surface of the heat transfer panel is corrugated and the fluid channel is disposed within ridges formed by the corrugated exterior surface.

5. A heat transfer system according to claim 4, wherein the exterior surface of the heat transfer panel is corrugated in accordance with the profile of a standard corrugated building panel.

6. A heat transfer system according to any one of claims 3 to 5, wherein the heat transfer panel comprises a plurality of mounting regions for fixing the heat transfer panel to a support structure, the plurality of mounting regions being distributed across the heat transfer panel.

7. A heat transfer system according to any one of claims 3 to 6, wherein the thermally conductive material defines the fluid channel and the exterior surface.

8. A heat transfer system according to any one of claims 3 to 7, wherein the heat transfer panel comprises a substantially uniform cross-sectional area, the substantially uniform cross sectional area having a repeated pattern along its length.

9. A heat transfer panel for use in a heat transfer system according to any one of claims 1 to 8.

10 A heat transfer panel unit comprising;

a fluid channel for carrying a heat transfer fluid, the heat transfer fluid being for use in heating and/or cooling a target;

an attachment plate for attachment of the heat transfer panel unit to a building panel having an exterior surface exposed to a surrounding environment; and

a thermally conductive material between the fluid channel and the attachment plate thereby allowing heat conduction between the heat transfer fluid and the attachment plate.

1 1. A heat transfer panel unit according to claim 10, wherein the attachment plate is shaped to complement an interior surface of the building panel which is a standard corrugated building panel.

12. A heat transfer system comprising;

a plurality of fluid channels for carrying heat transfer fluid;

a plurality of heat transfer components, each connected to at least one of the fluid channels;

a plurality of valves each arranged to control of fluid flow within at least one of the fluid channels, and

a control module, in controlling communication with the plurality of valves, the control module operable to dynamically control fluid flow within the fluid channels to control heat transfer between the plurality of heat transfer components.

13. A heat transfer system according to claim 10, wherein at least one of the plurality of heat transfer components is a heat transfer panel according to any one of claims 9 to 1 1 .

14. A heat transfer system according to claim 12 or claim 13, wherein at least one of the plurality of heat transfer components is a heat pump, a fluid storage tank and/or a heating and/or cooling target.

15. A heat transfer system according to any one of claims 12 to 14, wherein the control module is in controlling communication with at least one of the plurality of heat transfer components.

16. A heat transfer system according to any one of claims 12 to 15, wherein the control module comprises a plurality of sensors to detect the condition of an operating environment, and in response control fluid flow between the plurality of heat transfer components.

17. A heat transfer system according to claim 16, wherein the control module comprises a database and is arranged to log information about the condition of the operating environment over time, and from the information in the database, control fluid flow between the plurality of heat transfer components.

18. A heat transfer system according to claim 17, wherein the control module is arranged to analyse periodic characteristics of the operating environment, and in response control the fluid flow between the plurality of heat transfer components for future periods.