Heating system

Abstract

A heating system 10 comprising: a heat exchanger 20; an air intake 30 for transporting air to the heat exchanger, the air intake comprising a fan 32; a first exhaust 40, comprising an exhaust valve 42

Description

TECHNICAL FIELD The present disclosure relates to heating systems. Particularly, but not exclusively, the present disclosure relates to heating systems comprising heat exchangers that can be used in the heating of hot water and the spaces within a building. Aspects of the invention relate to a heating system and a method of controlling heating in a building. BACKGROUND For at least the last fifty years hot water and heating for most homes has been provided using fossil fuel-based heating systems in the form of simple boiler systems or more recently using combi-boiler systems to heat water. However, air source heat pumps (ASHPs) are an increasingly popular alternative to these traditional boiler systems as a heating option for homes. ASHPs, specifically the hot water air source type, are a sustainable and low carbon heating technology that extracts heat from air outside of the home and uses it to heat water for domestic use. This technology is becoming increasingly relevant to modern living as it can significantly reduce carbon emissions compared to traditional fossil fuel-based heating systems. ASHPs run using electricity, which can be obtained from renewable energy sources, thus reducing the overall carbon footprint of home heating. An ASHP operates by absorbing heat from the external air into a refrigerant fluid, which is then compressed to increase its temperature. The heated refrigerant transfers its heat to the water, which can be used for space heating within the home, including to heat radiators and to provide heat to underfloor heating systems. The heated water may also provide hot water for taps and showers. Even when the air temperature is low, ASHPs can extract heat, making them suitable for a variety of climates. Careful consideration still needs to be given to the insulation of the home and of the heating system to ensure that the overall system efficiency is optimised. It is an aim of the present invention to address one or more of the disadvantages associated with the prior art, in particular to improve the efficiency of an ASHP heating system. SUMMARY OF THE INVENTION Aspects and embodiments of the invention provide a heating system and a method of controlling heating in a building as claimed in the appended claims. According to an aspect of the present invention there is provided a heating system comprising: a heat exchanger; an air intake for transporting air to the heat exchanger, the air intake comprising an air intake fan; a first exhaust configured to vent air from the heat exchanger to an internal space of a building, the first exhaust comprising a first exhaust valve; a second exhaust configured to vent air from the heat exchanger to a space external to the building, the second exhaust comprising a second exhaust valve; and a controller, the controller configured to control the air intake fan, first exhaust valve, and second exhaust valve, dependent on the value of a plurality of heating parameters. An advantage of this aspect of the invention is that heating within a building can be efficiently controlled using a heat exchanger having variable ventilation paths for air expelled from the heat exchanger such that cooled air from the heat exchanger can be directed to vent internally or externally to the building, as required. The heat exchanger may comprise an air source heat pump. The plurality of heating parameters may comprise a first heating parameter and a second heating parameter. The controller may comprise a first control unit configured to control the air intake fan dependent on the value of a first heating parameter; and a second control unit configured to control the first exhaust valve and second exhaust valve, dependent on the value of a second heating parameter. The first heating parameter may indicate a status of a heating request. The heating system may comprise a user input device for input of a heating request. The user input device may communicate with the controller via a wireless connection. The user input device may be a mobile device. The heating request may indicate that heating of one or more systems is required. The systems that require heating may include one or more of a stored hot water system and space heating. The second heating parameter may indicate a measured temperature of an internal space of a building. The heating system may comprise a temperature sensor to measure the temperature of the internal space of the building. The temperature sensor may form part of a thermostatic controller or is connected thereto, either by a wired or wireless connection. A value of a temperature threshold may be retained by the controller for comparing the measured temperature of the internal space of the building with the temperature threshold. The temperature threshold may be set by a user using the user input device. The heating system may have a plurality of operational states. A first operational state may be active when there is no heating request, the first operational state causing the air intake fan to be inoperative; a second operational state may be active when there is a heating request and the measured temperature of the internal space of the building is less than or equal to the temperature threshold, the second operational state causing the air intake fan to be operative, closure of the first exhaust valve and opening of the second exhaust valve; and a third operational state may be active when there is a heating request and the measured temperature of the internal space of the building is greater than the temperature threshold, the third operational state causing opening of the air intake fan to be operative, opening of the first exhaust valve and closure of the second exhaust valve. The air intake may comprise an air intake port located in a loft space / void of the building. The heating system may comprise an air intake temperature sensor located proximal to the air intake port. A value of a first air intake temperature threshold may be retained by the controller; and a value of a second air intake temperature threshold may be retained by the controller; wherein the second air intake temperature threshold may be less than the first air intake temperature threshold. When a temperature measured at the air intake temperature sensor rises above the first air intake temperature threshold, one or more heat control fan may be active and / or one or more overheat vent may be open to the exterior of the building in order to reduce the temperature at the air intake port of the air intake. When the temperature measured at the air intake temperature sensor is less than the second temperature threshold the one or more heat control fan may be inactive and / or the one or more overheat vent may be closed. According to an aspect of the present invention there is provided a method of controlling heating in a building, the method comprising: receiving a plurality of heating parameters at a controller of a heating system, the heating system comprising a heat exchanger, the heat exchanger being operably connected to an air intake, a first exhaust, and a second exhaust; controlling, via the controller, an air intake fan of the air intake, a first exhaust valve of the first exhaust, and a second exhaust valve of the second exhaust, dependent on the value of the plurality of heating parameters; wherein the first exhaust valve is configured to control the venting of air from the heat exchanger to an internal space of a building, and the second exhaust valve is configured to control the venting of air from the heat exchanger to a space external to the building. Within the scope of this application, it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and / or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and / or features of any embodiment can be combined in any way and / or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and / or incorporate any feature of any other claim although not originally claimed in that manner. BRIEF DESCRIPTION OF THE DRAWINGS One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 illustrates a cutaway view of a building comprising a heating system according to an embodiment of the invention; Figure 2 illustrates a schematic diagram of a heating system according to an embodiment of the invention; Figure 3 illustrates a schematic diagram of an alternative heating system according to an embodiment of the invention; and Figure 4 illustrates a flow chart of a method of controlling heating in a building according to an embodiment of the invention. In the drawings, like parts are denoted by like reference numerals. DETAILED DESCRIPTION Examples of the present disclosure relate to a heating system, which may be used to improve the efficiency of heating a building, and a method of efficiently controlling heating in a building. Non-limiting examples will now be described with reference to accompanying Figures 1 to 4, where the figures illustrate a heating system 10 and a method 200 of controlling heating in a building 100, such as a home, using a heating system 10. Figure 1 illustrates a building 100 in which the heating system 10 may be located for the purpose of controlling the heating in the building 100. The heating system 10 operates using a heat exchanger 20, which may comprise an air source heat pump (ASHP), for transferring heat from one location to another location. In this way, the heat exchanger 20 may be used to provide heating in various locations within the building 100. In particular, in embodiments utilising an ASHP as the heat exchanger 20, heat is taken from an air source, which may be the air from a space external 120 to the building 100 or air present within, or passing through, an attic space, roof void, or loft space, 130. The air is drawn across heat exchange elements of the heat exchanger 20 by the operation of one or more heat exchanger fans, or air intake fans 32. That heat is then absorbed into a refrigerant fluid of the heat exchanger 20, which is then compressed to increase its temperature. The heated refrigerant may then transfer heat to water, which can be used for space heating within the building 100, including to heat radiators and to provide heat to underfloor heating systems, and / or to provide hot water for taps, showers and other user requirements. The building may comprise various internal spaces, such as an upper internal space 110 of the building 100, and a lower internal space 112 of the building 100, as illustrated in Figure 1, though it will be appreciated that buildings may take any form with any number of internal spaces that require heating. The heat which is then locally generated at the heat exchanger 20 may then be used to heat the various internal spaces of the building and / or to provide hot water for taps, showers and other user requirements. As illustrated in Figure 1, Figure 2, and Figure 3, the heating system 10 comprises the heat exchanger 20, which may be located in a heat exchanger housing 22 to prevent a user coming into contact with the heat exchanger elements. The heating system 10 further comprises an air intake 30, a first exhaust 40, and a second exhaust 50. The air intake 30 is configured or arranged to facilitate the transportation of air to the heat exchanger 20. The air intake 30 may comprise an air intake fan 32. In some embodiments, the air intake 30 may be in the form of a tube, pipe, or ducting leading from an air intake port 34 distal from the heat exchanger 20 to the heat exchanger 20 itself. The air intake 30 may comprise an open duct from the air intake port 34 into the heat exchanger 20, where air can be drawn into the heat exchanger 20 during operation of the heating system 10. An air intake fan 32 may be located at the heat exchanger 20. Additionally or alternatively, an air intake fan may be located at the air intake port 24. Additionally or alternatively, an air intake fan 32 may be located at a location within the air intake 30 between the air intake port 43 and the heat exchanger 20. In some embodiments, multiple air intake fans may be provided within the air intake 30 or at the heat exchanger 20. The, or each, air intake fan 32 may be controlled by the controller 60. In some embodiments the air intake 30 may comprise an air intake valve 38, which can open and close the air intake 30. In embodiments comprising both an air intake fan 32 and an air intake valve 38, the fan and valve may be operated together through control by the controller 60. In some embodiments, as illustrated in Figure 1, the air intake 30 has an air intake port 34 located in an attic space, roof void, or loft space 130 of the building 100. Air in the loft space 130 may be replenished via one or more vents 132 in the roof 134 of the building 100. That is, when air is drawn into the air intake 30 of the heating system 10, to subsequently be passed through the heat exchanger 20 and then to be vented via the first exhaust 40 or second exhaust 50, air is drawn into the loft space 130 from the space external 120 to the building 100 via the vents 132 in the roof 134. In order to monitor the temperature in the loft space 130, an air intake temperature sensor 36 may be located proximal to the air intake port 34. A value of a first air intake temperature threshold and a value of a second air intake temperature threshold may be retained, either by the controller 60 of the heating system 10 or by a separate controller which may form part of an overheat control system for the loft space 130. The second air intake temperature threshold is less than the first air intake temperature threshold such that temperature control within the loft space 130 can be provided with multiple thresholds to control components of the overheat control system for the loft space 130 whilst minimising frequent switching and / or activation of components of the overheat control system. At least some functions and / or components of the overheat control system are provided in the loft space 130. In some embodiments, functions and / or components of the overheat control system may be controlled by a dedicated controller of the overheat control system, separate to the controller 60 of the heating system 10. However, in other the control of the various functions / components of the overheat control system can be handled by the controller 60 of the heating system 10. The overheat control system in the loft space 130 comprises the air intake temperature sensor 36, an overheat vent 136 forming a ventilation passage through the roof 134 of the building 100 between the loft space 130 and the space external 120 to the building 100, and an overheat vent fan 138 positioned at or near the overheat vent 136. The overheat vent 136 can be moved between an open position and a closed position, the open position allowing air from the loft space 130 to pass out to the space external 120 to the building 100, and the closed position preventing air from the loft space 130 passing out to the space external 120 to the building 100. The overheat vent fan 138 can be controlled to operate when the overheat vent 136 is in an open position. In some embodiments, the overheat vent fan 138 may operate at variable speeds dependent on the temperature measured at the air intake temperature sensor 36. When a temperature measured at the air intake temperature sensor 36 rises above the first air intake temperature threshold, the overheat vent 136 is configured or arranged to open to the exterior 120 of the building 100, that is the space external 120 to the building 100, and the overheat vent fan 138 is active in order to reduce the temperature at the air intake port 34 of the air intake 30. The first air intake temperature threshold may be, for example, a value selected between 25°C and 35°C, though always higher than the value of the second air intake temperature threshold, preferably a value selected between 28°C and 32°C, though always higher than the value of the second air intake temperature threshold, and in one embodiment is 30°C when, for example the second air intake temperature threshold is 25°C. When the temperature measured at the air intake temperature sensor 36 is less than the second temperature threshold the overheat vent 136 is configured or arranged to close and the overheat vent fan 138 is inactive. The second air intake temperature threshold may be, for example, a value selected between 20°C and 30°C, though always lower than the value of the first air intake temperature threshold, preferably a value selected between 23°C and 27°C, though always lower than the value of the first air intake temperature threshold, and in one embodiment is 25°C when, for example the first air intake temperature threshold is 30°C. In some embodiments, a plurality of overheat vents 136 and respective overheat vent fans 138 can be provided in the loft space 130, each controlled dependent upon the temperature measured at the air intake temperature sensor 36, or, in an alternative embodiment, each separately controlled dependent upon a temperature measured at respective separate air intake temperature sensors 36. The air intake fan 32 may be located at any location along the air intake 30. I In some embodiments an air intake fan 32 may be located at an end of the air intake 30 proximal to the heat exchanger 20, and may be located within a heat exchanger housing 22. By locating an air intake fan 32 proximal to the heat exchanger 20, the electronics to control the air intake fan 32 may be located close to the heat exchanger 20 which may then provide for a more compact and / or simplified arrangement of the heating system 10. The first exhaust 40 is configured to vent or expel air from the heat exchanger 20, that is to facilitate the transportation of air away from the heat exchanger 20. The first exhaust 40 may vent air from the heat exchanger 20 to an internal space 110, 112 of a building. The first exhaust 40 may comprise a first exhaust valve 42. In some embodiments, the first exhaust 40 may be in the form of a tube, pipe, or ducting leading from the heat exchanger 20 to an internal space 110, 112 of the building. The first exhaust valve 42 may be located at any location along the first exhaust 40, but in some embodiments the first exhaust valve 42 is located at an end of the first exhaust 40 proximal to the heat exchanger 20, and may be located within the heat exchanger housing 22. By locating the first exhaust valve 42 proximal to the heat exchanger 20, the electronics to control the first exhaust valve 42 may be located close to the heat exchanger 20 which may then provide for a more compact and / or simplified arrangement of the heating system 10. The second exhaust 50 is configured to vent or expel air from the heat exchanger 20, that is to facilitate the transportation of air away from the heat exchanger 20. The second exhaust 50 may vent air from the heat exchanger 20 to a space external 120 to the building. Alternatively, the second exhaust 50 may vent air from the heat exchanger 20 to an internal space 110, 112 of a building different to that to which the first exhaust 40 vents air. The second exhaust 50 may comprise a second exhaust valve 52. In some embodiments, the second exhaust 50 may be in the form of a tube, pipe, or ducting leading from the heat exchanger 20 to a space external 120 to the building. The second exhaust valve 52 may be located at any location along the second exhaust 50, but in some embodiments the second exhaust valve 52 is located at an end of the second exhaust 50 proximal to the heat exchanger 20, and may be located within the heat exchanger housing 22. By locating the second exhaust valve 52 proximal to the heat exchanger 20, the electronics to control the second exhaust valve 52 may be located close to the heat exchanger 20 which may then provide for a more compact and / or simplified arrangement of the heating system 10. In particular, the electronics to control the operation of the air intake fan 32, the first exhaust valve 42, and the second exhaust valve 52 may be collocated, and may all be located within a heat exchanger housing 22 of the heat exchanger 20 or within a separate housing proximal to the heat exchanger 20. In an alternative embodiment, a single exhaust valve may be connected to both the first exhaust 40 and second exhaust 50. In such an arrangement, the exhaust valve can be selectable between a first position, where air is vented via the first exhaust 40, and a second position, where air is vented via the second exhaust 50. The heating system 10 also comprises control means, which may be in the form of a controller 60 or control circuitry. The controller 60 is configured to control the air intake fan 32, the first exhaust valve 42, and the second exhaust valve 52, dependent on the value of a plurality of heating parameters, where the heating parameters are received and / or stored at the controller 60. In some embodiments, different elements of the heating system 10, in particular the air intake fan 32, the first exhaust valve 42, and the second exhaust valve 52, may be controlled using separate controllers 60, or separate control units within the controller 60. For example, in one embodiment, the air intake fan 32 may be controlled by a first control unit 60-1 or first controller, and the first exhaust valve 42 and second exhaust valve 52 may be controlled by a second control unit 60-2 or second controller. The, or each, controller 60 or control unit comprises a processing means, which may be in the form of a processor 62 or processing circuitry, a storage means, which may be in the form of a memory 64 or memory circuitry, and communication means, which may be in the form of a transceiver 66, communication circuitry and / or input and output means. The air intake fan 32, the first exhaust valve 42, and the second exhaust valve 52 may be controlled, by a controller 60, or in some embodiments a plurality of controllers 60, based on a plurality of received and / or stored heating parameters. The plurality of heating parameters comprises, at least, a first heating parameter and a second heating parameter. The air intake fan 32 may be controlled by the controller 60 via a first control output, or air intake fan control output 70. The first exhaust valve 42 may be controlled by the controller 60 via a second control output, or first exhaust valve control output 72. The second exhaust valve 52 may be controlled by the controller 60 via a third control output, or second exhaust valve control output 74. The air intake fan control output 70, the first exhaust valve control output 72, and the second exhaust valve control output 74 may provide signals and / or power to operate the respective associated fan, to either be operable or inoperable, and the respective associated valves, to either open or close the respective valves. In embodiments where the air intake fan 32 may be controlled using a first control unit 60-1 and the first exhaust valve 42 and second exhaust valve 52 may be controlled using a second control unit 60-2 separate to the first control unit 60-1, the first control unit 60-1 is configured to control the air intake fan 32 dependent on the value of a first heating parameter, and the second control unit 60-2 is configured to control the first exhaust valve 42 and second exhaust valve 52, dependent on the value of a second heating parameter. The first control unit 60-1 and the second control unit 60-2 together performing the control functions of the heating system 10. For simplicity, the embodiments illustrated in Figure 1, Figure 2, and Figure 3 comprise a single controller 60 for performing the control functions of the heating system 10, the controller 60 receiving and / or storing the plurality of heating parameters. The first heating parameter may indicate a status of a heating request. The heating request may be a value of a demand for heating provided by either a user of the heating system 10 or by the operation of an automated heating system 10. The value of the demand for heating may signify that either there is a heating request or there is no heating request. The heating request may indicate that heating of one or more systems is required, where the one or more systems may comprise, for example, a stored hot water system, for providing hot water to taps or showers in the building, and space heating, including heating internal spaces 110, 112, of the building 100 via radiators and underfloor heating. It can be confirmed, via the first heating parameter, that heating is required when there is a positive heating request, that is, when the value of the demand for heating is a positive value or positive signal received at or provided to the controller 60. A positive signal could be, for example a binary value of 1 in a digital control system, or a voltage level such as +5V in an analogue control system. It can also be confirmed, via the first heating parameter, that heating is not required when there is no heating request, that is, when the value of the demand for heating is a negative value or negative signal, or when there is no value or signal at all, provided to the controller 60. A negative signal could be, for example a binary value of 0 in a digital control system, or a voltage level such as 0V or -5V in an analogue control system, which can be easily distinguished from a positive heating request, by the controller 60, from the received input. Input of a heating request, in other words a demand for heating, may be provided in a number of different ways. For example, the heating system 10 may comprise a user input device 80. The user input device 80 may be configured or arranged to allow a user to input a heating request, which may be an on-demand heating request. It will be understood, that in most embodiments, without any user input, the controller 60 should default to there being no heating request, and therefore provide no heating function via the heating system 10. The user input device 80 may communicate with the controller 60 via a wireless connection. Alternatively, the user input device 80 may communicate with the controller 60 via a wired connection. The user input device 80 may, in some embodiments, be collocated with the controller 60, that is, be hardwired at the controller 60. In some embodiments, the user input device 80 may be hardwired to the controller 60 but be located remotely therefrom, for example to be located in an internal space 110, 112 of the building 100 that the user frequents, such as a mixing zone in the building 100. In some embodiments, the user input device 80 may be wirelessly connected to the controller 60 but be remote therefrom, for example located in an internal space 110, 112 of the building 100 that the user frequents, such as a mixing zone in the building 100. Wireless connection may be via Bluetooth, LAN, WAN, Cellular or any other wireless network or networks. In some embodiments, the user input device 80 may be a mobile device that the user may carry, for example a mobile telephone with the functionality to receive user input and transmit user defined heating requests to the controller 60. In some embodiments multiple user input devices 80 may be present, for example a mobile device in the form of a mobile telephone that the user may carry, and a hardwired user input device 80 located within an internal space 110, 112 of the building 100 that the user frequents may both be capable of receiving user input for the provision of heating requests. In an additional, or alternative, arrangement, a heating request may be provided via a preprogrammed timing system. A user may pre-program the timing system, either via the user input device 80 or via another input means, such that a positive heating request is provided at predetermined days / times without the need for any on-demand heating request from a user. The user input device 80 may be, or form part of, a temperature control system, thermostat, or thermostatic controller 92, connected via a wired connection or connected wirelessly to the controller 60. The second heating parameter may indicate a measured temperature of an internal space 110,112 of the building 100. In order to provide the measured temperature, the heating system 10 may comprise a temperature measurement device, for example a temperature sensor 90, to measure the temperature of an internal space 110,112 of the building 100. The temperature sensor 90 may form, or form part of, a temperature control system, thermostat, or a thermostatic controller 92 or may be connected thereto, either by a wired or wireless connection. The temperature sensor 90, or the thermostatic controller 92, may communicate with the controller 60 via a wired or wireless connection. The controller 60 may receive a temperature value from the temperature sensor 90 or thermostatic controller 92. The controller 60 may retain or store a value of a temperature threshold for the internal space 110, 112 of the building 100, which may be called a room temperature threshold, such that the measured temperature of the internal space 110, 112 of the building 100 can then be compared with the stored temperature threshold. The temperature threshold value may be retained or stored in the memory 64 of the controller 60. In order for the controller 60 to have a temperature threshold to which the measured temperature of the internal space 110, 112 of the building 100 can be compared, the temperature threshold can be predefined or set by a user. In some embodiments the temperature threshold may be set using the user input device 80, such that the controller 60 receives the temperature threshold value for the internal space 110, 112 of the building 100 from the user input device 80. However, there may be alternative methods of setting the temperature threshold without using the user input device 80, such as by direct input into a separate temperature control system or by input into a thermostat or thermostatic controller 92 separate to, or associated with, a user input device 80. In some embodiments, multiple methods for setting the temperature threshold may be provided, such as through a user input device 80 and a separate thermostat or thermostatic controller 92. The temperature threshold may be set at a particular user defined value, such as 25°C. The temperature threshold effectively defines how the air to be expelled, or vented, from the heat exchanger, is to be routed, that is, via which of the first exhaust 40 or second exhaust 50, the air is to be expelled or vented. The heating system 10 is configured or arranged to have a plurality of operational states, dependent upon the status of a heating request and a measured temperature of the internal space 110, 112 of the building 100 in which the temperature sensor 90 is located. A first operational state is active when there is no heating request. The first operational state causes the air intake fan 32 to be inoperative such that there is no air supplied to the heat exchanger 20. A second operational state is active when there is a heating request and the measured temperature of the internal space 110, 112 of the building 100 is less than or equal to the temperature threshold. The second operational state causes the air intake fan 32 to be operative, closure of the first exhaust valve 42, and opening of the second exhaust valve 52. In this second operational state, cool air produced during the heat exchange process at the heat exchanger 20 is vented to the outside, or space external, 120 of the building 100, thereby preventing cooling of the internal space 110, 112 of the building 100. A third operational state is active when there is a heating request and the measured temperature of the internal space 110, 112 of the building 100 is greater than the temperature threshold. The third operational state causes the air intake fan 32 to be operable, opening of the first exhaust valve 42, and closure of the second exhaust valve 44. In this third operational state, cool air produced during the heat exchange process at the heat exchanger 20 is vented to an internal space 110, 112 of the building 100, thereby providing cooling of the internal space 110, 112 of the building 100, and in the embodiment illustrated in Figure 1, cooling of, at least, the upper internal space 110 of the building 100. In some embodiments, the cooled air vented from the first exhaust 40 can be vented to a mixing zone in the building 100, such as a landing or hallway, thereby providing optimal cooling of the building 100. In some embodiments, the heating system 10 comprises a pressure release vent 102 comprising a valve that can be selectively in an open state, or condition, and a closed state, or condition, dependent upon the operational state of the heating system 10. In the third operational state the cool air produced during the heat exchange process at the heat exchanger 20 is vented to an internal space 110, 112 of the building 100, thereby providing cooling of the internal space 110, 112 of the building 100, for example cooling of an upper internal space 110 of the building 100 which may be a mixing zone in the building 100. However, by venting the cooled air to the internal space 110, 112 of the building, increased pressure, or a positive pressure, may be created within the internal space 110, 112 of the building. In order to balance the pressure within the internal space 110, 112 of the building, the pressure release vent 102 may be open when the heating system 10 is in the third operational state, that is when the heating system 10 is venting the cool air from the heat exchanger 20 to the internal space 110, 112 of the building 100. In some embodiments, the pressure release vent 102 is electronically controlled, via the controller 60 or a separate controller, to be opened automatically when the heating system 10 is venting the cool air produced during the heat exchange process to the internal space 110, 112 of the building 100. In alternative embodiments, the pressure release vent 102 is electronically controlled, via the controller 60 or a separate controller, for example a controller at the pressure release vent 102 itself. The pressure release vent 102 is controlled to be opened automatically when a pressure, measured within the building 100, is above a predetermined pressure threshold, indicating an increased internal pressure that requires venting of the air within the building 100 to the space external 120 to the building 100, in order to balance the pressure inside the building 100. The pressure within the building 100 may be measured by any known pressure measurement device. The pressure measurement device may provide data to the controller 60, or the separate controller, that can be used to ascertain a requirement to open the pressure release vent 102. The controller 60, or the separate controller, may then provide a signal to the pressure release vent 60 to open the pressure release vent 102. When the measured pressure is below the predetermined pressure threshold, the controller 60 or the separate controller, may then provide a signal to the pressure release vent 60 to close the pressure release vent 102. In an alternative embodiment, as illustrated in Figure 3, the heating system 10 may be as described above, with the addition of an air intake valve 38 in the path of the air intake 30. The air intake valve 38 may prevent air from being drawn into the heat exchanger 20. The air intake valve 38 may be located at any location along the air intake 30. In some embodiments an air intake valve 38 may be located at an end of the air intake 30 proximal to the heat exchanger 20, and may be located within a heat exchanger housing 22. By locating an air intake valve 38 proximal to the heat exchanger 20, the electronics to control the air intake valve 38 may be located close to the heat exchanger 20 which may then provide for a more compact and / or simplified arrangement of the heating system 10. In embodiments comprising an air intake valve 38, the electronics to control the operation of the air intake valve 38, the air intake fan 32, the first exhaust valve 42, and the second exhaust valve 52, may be collocated, and may all be located within a heat exchanger housing 22 of the heat exchanger 20 or within a separate housing proximal to the heat exchanger 20. The controller 60 of the heating system 10, which may be in the form of a controller 60 or control circuitry, is configured to control the air intake valve 38, the air intake fan 32, the first exhaust valve 42, and the second exhaust valve 52, dependent on the value of a plurality of heating parameters, where the heating parameters are received and / or stored at the controller 60. In some embodiments, different fans and valves may be controlled using separate controllers 60, or separate control units within the controller 60. For example, the air intake valve 38 and air intake fan 32 may be controlled by a first control unit 60-1 or first controller, and the first exhaust valve 42 and the second exhaust valve 52 may be controlled by a second control unit 60-2 or second controller. The, or each, controller 60 or control unit comprises a processing means, which may be in the form of a processor 62 or processing circuitry, a storage means, which may be in the form of a memory 64 or memory circuitry, and communication means, which may be in the form of a transceiver 66, communication circuitry and / or input and output means. The air intake valve 38 may be controlled by the controller 60 via a fourth control output, or air intake valve control output 76. The air intake valve control output 76 may provide signals and / or power to operate the air intake valve 38 to either open or close. Figure 4 shows a flow diagram for the method 200 of controlling heating in a building 100, using a heating system 10 as described above. At block 202 a plurality of heating parameters are received at a controller 60 of a heating system 100, where the heating system comprises a heat exchanger 20, the heat exchanger 20 being operably connected to an air intake 30, a first exhaust 40, and a second exhaust 50. At block 204 an air intake fan 32 of the air intake 30, a first exhaust valve 42 of the first exhaust 40, and a second exhaust valve 52 of the second exhaust 50 are controlled, via the controller 60, dependent on the value of the plurality of heating parameters. In the heating system 10 for this method 200, the first exhaust valve 42 is configured to control the venting of air from the heat exchanger 20 to an internal space 110, 112 of a building 100, and the second exhaust valve 52 is configured to control the venting of air from the heat exchanger 20 to a space external 120 to the building 100. The blocks illustrated in Figure 4 may represent steps in a method. The illustration of a particular order to the blocks does not necessarily imply that there is a required or preferred order for the blocks and the order and arrangement of the blocks may be varied. Furthermore, it may be possible for some blocks to be omitted. Although embodiments of the present invention have been described in the preceding paragraphs with reference to various examples, it should be appreciated that various changes and modifications to the examples given can be made without departing from the scope of the invention as claimed. In particular, whilst the examples provided in Figures 1 to 4 illustrate various arrangements of a heating system and the operation of a heating system, it will be understood that the claimed invention is not limited to these specific examples but extends to other combinations of these arrangements as encompassed by the claims. For example, additional exhausts can be provided at the heat exchanger 20 to vent air to different spaces within the building 100 depending on the temperature of those spaces. With additional exhausts, additional or alternative exhaust valve arrangements may be provided, where potentially multiple exhausts are open at the same time, and conversely multiple exhausts could be closed at the same time. Features described in the preceding description may be used in combinations other than the combinations explicitly described. Although functions have been described with reference to certain features, those functions may be performable by other features whether described or not. Although features have been described with reference to certain embodiments, those features may also be present in other embodiments whether described or not. Whilst endeavouring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and / or shown in the drawings whether or not particular emphasis has been placed thereon.

Claims

1. A heating system comprising:a heat exchanger, wherein the heat exchanger comprises an air source heat pump;an air intake for transporting air to the heat exchanger, the air intake comprising an air intake fan;a first exhaust configured to vent air from the heat exchanger to an internal space of a building, the first exhaust comprising a first exhaust valve;a second exhaust configured to vent air from the heat exchanger to a space external to the building, the second exhaust comprising a second exhaust valve; anda controller, the controller configured to control the air intake fan, first exhaust valve, and second exhaust valve, dependent on the value of a plurality of heating parameters.

2. A heating system according to claim 1, wherein the plurality of heating parameters comprises a first heating parameter and a second heating parameter.

3. A heating system according to claim 2, wherein the controller comprises a first control unit configured to control the air intake fan dependent on the value of a first heating parameter; and a second control unit configured to control the first exhaust valve and second exhaust valve, dependent on the value of the second heating parameter.

4. A heating system according to claim 2 or claim 3, wherein the first heating parameter indicates a status of a heating request.

5. A heating system according to claim 4, comprising a user input device for input of a heating request.

6. A heating system according to claim 5, wherein the user input device communicates with the controller via a wireless connection.

7. A heating system according to claim 5 or claim 6, wherein the user input device is a mobile device.

8. A heating system according to any of claims 4 to 7, wherein the heating request indicates that heating of one or more systems is required.

9. A heating system according to claim 8, wherein the systems that require heating include one or more of a stored hot water system and space heating.

10. A heating system according to any of claims 4 to 9, wherein the second heating parameter indicates a measured temperature of an internal space of a building.

11. A heating system according to claim 10, the heating system comprising a temperature sensor to measure the temperature of the internal space of the building.

12. A heating system according to claim 11, wherein the temperature sensor forms part of a thermostatic controller or is connected thereto, either by a wired or wireless connection.

13. A heating system according to any of claims 10 to 12, wherein a value of a temperature threshold is retained by the controller for comparing the measured temperature of the internal space of the building with the temperature threshold.

14. A heating system according to claim 13, wherein the temperature threshold is set by a user using the user input device.

15. A heating system according to any of claims 10 to 14, wherein the heating system has a plurality of operational states.

16. A heating system according to claim 15, wherein a first operational state is active when there is no heating request, the first operational state causing the air intake fan to be inoperative; a second operational state is active when there is a heating request and the measured temperature of the internal space of the building is less than or equal to the temperature threshold, the second operational state causing the air intake fan to be operative, closure of the first exhaust valve and opening of the second exhaust valve; and a third operational state is active when there is a heating request and the measured temperature of the internal space of the building is greater than the temperature threshold, the third operational state causing the air intake fan to be operative, opening of the first exhaust valve and closure of the second exhaust valve.

17. A heating system according to any preceding claim, wherein the air intake comprises an air intake port located in a loft space / void of the building.

18. A heating system according to claim 17, comprising an air intake temperature sensor located proximal to the air intake port.

19. A heating system according to claim 18, wherein a value of a first air intake temperature threshold is retained by the controller; and a value of a second air intake temperature threshold is retained by the controller; wherein the second air intake temperature threshold is less than the first air intake temperature threshold.

20. A heating system according to claim 19, wherein, when a temperature measured at the air intake temperature sensor rises above the first air intake temperature threshold, one or more heat control fan is active and / or one or more overheat vent is open to the exterior of the building in order to reduce the temperature at the air intake port of the air intake.

21. A heating system according to claim 20, wherein when the temperature measured at the air intake temperature sensor is less than the second temperature threshold the one or more heat control fan is inactive and / or the one or more overheat vent is closed.

22. A method of controlling heating in a building, the method comprising:receiving a plurality of heating parameters at a controller of a heating system, the heating system comprising a heat exchanger, wherein the heat exchanger comprises an air source heat pump, the heat exchanger being operably connected to an air intake, a first exhaust, and a second exhaust;controlling, via the controller, an air intake fan of the air intake, a first exhaust valve of the first exhaust, and a second exhaust valve of the second exhaust, dependent on the value of the plurality of heating parameters;wherein the first exhaust valve is configured to control the venting of air from the heat exchanger to an internal space of a building, and the second exhaust valve is configured to control the venting of air from the heat exchanger to a space external to the building.s

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