Heat recovery apparatus and methods

Abstract

HVAC / CRAC air cooling equipment for a data centre with a liquid to air heat exchanger (HX) can operate in two modes. A normal chiller mode (dotted line) with supply coolant 4 routed to a HX input 24

Description

FIELD OF THE INVENTION The present invention relates to heating, ventilation and air conditioning (HVAC) systems. In particular, the present invention relates to heat recovery methods and apparatus for adjusting the temperature of air supplied to a room such as a data hall. BACKGROUND TO THE INVENTION Rooms which house electronic equipment such as computer servers are often provided with cooling systems to remove waste heat generated by the electronic equipment. To reduce the risk of failure, and to prolong the life of the electronic equipment, it is desirable to maintain air temperatures in such rooms within a suitable operating range for the equipment. It is also desirable to prevent excessive fluctuations in temperature and / or humidity, which can be associated with problems such as condensation or static electricity build-up. Air in relatively smaller server rooms may be cooled using standalone (e.g. split-system) air conditioning units, whilst server cabinets in relatively larger data halls (for example within a data centre) may be cooled using liquid-cooled air handling units which are fed with a supply of chilled liquid (such as chilled water from a central chiller) in order to provide cooled air at a desired location. Energy usage by such cooling systems can contribute considerably to the running costs of electronic equipment, and there is an established need to reduce energy use by such systems for economic and environmental reasons. With improvements to electronic components, it has become possible for some electronic equipment to be operated reliably at higher room air temperatures, which can help to reduce energy usage by reducing the amount of cooling required. Alongside cooling systems, electronic equipment rooms may also be provided with ventilation systems to provide fresh replacement air into the room. These systems may be used to help maintain air quality for personnel working in the rooms and to manage humidity. These systems may also provide make-up air to replace air removed from the room by extraction, filtering and / or air conditioning systems, and / or to generate positive pressure in the room. Ventilation systems may further contribute to the energy consumption of an electronic equipment room, and may increase the load placed on cooling systems by introducing ambient air into the room. It is against this background that the present invention has been devised. It is an object of the present invention to overcome at least one problem associated with the prior art, whether referred to herein or otherwise. SUMMARY OF THE INVENTION According to a first aspect of the invention there is provided apparatus for adjusting the temperature of air supplied to a room, the apparatus being connectable in fluid communication with a fluid cooling arrangement for cooling electronic equipment, said cooling arrangement comprising a coolant supply path for supplying chilled coolant to the fluid cooling arrangement and a coolant return flow path for returning spent coolant from the fluid cooling arrangement, wherein the apparatus comprises: a heat exchange unit configured to heat or cool incoming air prior to supplying the air to said room, and the heat exchange unit being connectable in fluid communication with the fluid cooling arrangement; wherein the apparatus is switchable between a first configuration, in which the apparatus is configured to direct chilled coolant from a coolant supply to the heat exchange unit, thereby to cool the air supplied to the room, and a second configuration in which the apparatus is configured to direct spent coolant from the coolant return flow path to the heat exchange unit, thereby to heat the air supplied to the room using the spent coolant from the fluid cooling arrangement. With this arrangement, the apparatus is arranged to utilise waste heat recovered from the electronic equipment to provide temperature adjusted air to the room, which can help to reduce the energy consumption associated with adjusting the temperature of air to the room. The apparatus may comprise the fluid cooling arrangement. The apparatus may be connected in fluid communication with the fluid cooling arrangement. Preferably, when the apparatus is in the first configuration, the heat exchange unit is arranged to receive coolant from the coolant supply path of the fluid cooling arrangement. In this way, the apparatus may be connected in fluid communication with an existing cooling arrangement. For example the coolant supply path may comprise a chilled water feed of a fluid cooling system. For example, an inlet of the heat exchange unit may be connected to the coolant supply path and / or to the coolant return flow path. Preferably an outlet of the heat exchange unit is in fluid communication with the coolant return flow path, thereby to return coolant from the heat exchange unit to the coolant return flow path. In this way, the apparatus may be connected in fluid communication with the return flow of an existing cooling arrangement. For example the coolant return flow path may comprise a water return conduit of a fluid cooling system. The electronic equipment may be located in the room to which air is to be supplied. Preferably the apparatus is configured to adjust the temperature of air supplied to a room in which the electronic equipment is located, such that heat recovered from the electronic equipment by the fluid cooling arrangement is used to heat the air supplied to the room. With this arrangement, the apparatus is arranged to utilise heat waste heat recovered from the electronic equipment to provide temperature adjusted air to the same room in which the equipment is located. This can help to reduce the energy consumption associated with adjusting the temperature of air to the room. The apparatus may be configured to switch to the second configuration upon a temperature in the room falling below a predetermined temperature. The apparatus may be configured to switch from the first configuration to the second configuration upon a temperature in the room falling below a predetermined temperature. The apparatus may be configured to switch to the second configuration upon a temperature of air entering the apparatus falling below a predetermined temperature. The apparatus may be configured to switch from the first configuration to the second configuration upon a temperature of air entering the apparatus falling below a predetermined temperature. Preferably the apparatus comprises a valve arrangement connected or connectable in fluid communication with the coolant supply path and the coolant return flow path and connected in fluid communication with an inlet of the heat exchange unit. In this case, preferably, in the first configuration, the valve arrangement is configured to direct coolant to flow from the coolant supply path to the heat exchange unit and in the second configuration, the valve arrangement is configured to direct spent coolant to flow from the coolant return flow path to the heat exchange unit. Preferably the valve arrangement comprises a three-way valve or three port valve. In this case, preferably a first port of the valve is in fluid communication with the coolant supply path and a second port of the valve is in fluid communication with the coolant return flow path. Preferably a third port of the valve is in fluid communication with the heat exchange unit. Preferably in the first configuration the valve arrangement blocks coolant flow from the coolant return flow path to the heat exchange unit. Preferably, in the second configuration, the valve arrangement blocks coolant flow from the coolant supply path to the heat exchange unit. The heat exchange unit may comprise a heat exchanger. The heat exchange unit may comprise a heat exchanger having only a single fluid inlet and / or a single fluid outlet. The heat exchange unit may comprise two or more heat exchangers. Preferably the heat exchange unit comprises a heat exchanger having a fluid flow path and preferably, in the first configuration, chilled coolant is directed to flow through the fluid flow path and in the second configuration, spent coolant is directed to flow through the fluid flow path. In this way, chilled coolant or spent coolant flows through the same fluid flow path of the heat exchanger. The apparatus may comprise a pump arranged to pump coolant through the heat exchange unit. The pump may be arranged to pump coolant from the coolant return flow path to the heat exchange unit. The apparatus may comprise a fan arranged to move air through the heat exchange unit and into the room. The apparatus may be configured to provide positive air pressure in the room. The apparatus may be configured to provide make-up air into the room. According to a second aspect of the invention there is provided a heat recovery system comprising apparatus according to the first aspect of the invention and comprising the fluid cooling arrangement, in which the heat exchange unit is connected in fluid communication with the fluid cooling arrangement such that, in the first configuration, the heat exchange unit receives chilled coolant from the coolant supply path, thereby to cool incoming air, and in the second configuration the heat exchange unit receives spent coolant from the coolant return flow path, thereby to heat incoming air using the spent coolant from the fluid cooling arrangement. The heat recovery system may comprise two or more of the apparatus according the first aspect of the invention. According to a third aspect of the invention there is provided a room comprising apparatus according to the first aspect of the invention, or the heat recovery system according to the second aspect of the invention. Preferably the room comprises a data hall. According to a fourth aspect of the invention there is provided an air-handling unit comprising apparatus according to the first aspect of the invention. The air-handling unit may comprise a fan. According to a fifth aspect of the invention there is provided a method for adjusting the temperature of air supplied to a room, the method comprising: providing a heat exchange unit arranged to adjust the temperature of the air supplied to the room, the heat exchange unit being connectable in fluid communication with a fluid cooling arrangement for cooling electronic equipment, said fluid cooling arrangement having a coolant supply path for supplying chilled coolant to the fluid cooling arrangement and a coolant return flow path for returning spent coolant from the fluid cooling arrangement; and, operating the heat exchange unit in a heat recovery configuration by directing spent coolant from the coolant return flow path to the heat exchange unit, thereby to heat the air supplied to the room. The electronic equipment may be located in the room to which air is to be supplied. Preferably the heat exchange unit is operated in the heat recovery configuration when it is required to heat the air supplied to the room. Preferably the method comprises operating the heat exchange unit in a cooling configuration by directing coolant from the coolant supply path to the heat exchange unit, thereby to cool the air supplied to the data hall. Preferably the heat exchange unit is operated in the cooling configuration when it is required to cool the air supplied to the room. The method may comprise determining a temperature in the room and directing coolant to the heat exchanger from the coolant return flow path in response to the determined temperature falling below a predetermined temperature. The method may comprise determining a temperature of incoming air supplied to the heat exchange unit and directing spent coolant to the heat exchange unit from the coolant return flow path in response to the determined temperature of said incoming air falling below a predetermined temperature. Preferably the method comprises comprising returning coolant from the heat exchanger to the coolant return flow path. The method may comprise providing a heat exchange unit arranged to adjust the temperature of the air supplied to the room in which the electronic equipment is located, such that heat recovered from the electronic equipment by the fluid cooling arrangement is used to heat the air supplied to the room. Preferably the method comprises providing a valve arrangement connectable in fluid communication with the coolant supply path and the coolant return path and connected in fluid communication with an inlet of the heat exchange unit, wherein, in a cooling configuration, the valve arrangement is configured to direct coolant to flow from the coolant supply path to the heat exchange unit and in the heat recovery configuration, the valve arrangement is configured to direct spent coolant to flow from the coolant return flow path to the heat exchange unit. The method may comprise fitting (e.g. retrofitting) the heat exchange unit and / or the valve arrangement to a fluid cooling arrangement. In this way, apparatus according to the invention and / or the heat recovery system may be provided by fitting the heat exchange unit and valve arrangement to a pre-existing fluid cooling arrangement such as a fluid cooling system of a room such as a data hall. BRIEF DESCRIPTION OF THE DRAWINGS Embodiments of the present invention will now be described by way of example only with reference to the accompanying drawings, in which like reference numerals indicate like features and in which: Figure 1 is a schematic diagram of apparatus according to a preferred embodiment of the invention, together with part of a fluid cooling arrangement to which the apparatus may be connected, showing the apparatus operating in a first, cooling configuration; and Figure 2 is a schematic diagram of apparatus according to a preferred embodiment of the invention, together with part of a fluid cooling arrangement to which the apparatus may be connected, showing the apparatus operating in a second, heat recovery configuration. DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention provides apparatus and methods for providing temperature-adjusted air to a room such as a data hall. In particular, the present invention allows waste heat from a cooling system of the room to be recovered and used to heat the air provided to the room. The present invention also provides a heat recovery system comprising the apparatus and the cooling system together. The apparatus of the present invention is particularly suitable for providing ventilation and / or makeup air to a room such as data hall. Figures 1 and 2 show schematic diagrams of heat recovery apparatus 10 according to a preferred embodiment of the invention, together with parts of a fluid cooling system or fluid cooling arrangement 2 to which the apparatus may be connected. The apparatus 10 is arranged to supply air to a room such as a data hall (not shown). The cooling system is a fluid cooling system for cooling the room and / or equipment in the room, such as one or more servers (not shown). The fluid cooling system comprises a coolant supply path 4 (which in this example is a chilled water feed) and a coolant return flow path 6 (which in this example is a water return feed). The coolant supply path is arranged to carry chilled coolant to parts of the cooling system (not shown) within the room, to cool air in the room and / or to cool the equipment located in the room. Coolant which has absorbed heat from the room (which may be referred to as spent coolant) is returned via the coolant return flow path 6. The spent coolant may be returned to a central chiller unit (not shown) where the coolant is chilled and waste heat is rejected to the external environment, before the chilled coolant is returned / recycled to the coolant supply path 4. In this specification, the term “coolant” refers to any fluid suitable for transferring heat in a cooling system, and such fluid may also be referred to as “heat-transfer fluid”. The term “room” refers to any space to which temperature-adjusted air may be supplied. For example, the room may be a cupboard or cabinet, a data hall or data centre, warehouse or similar. In this embodiment, the apparatus 10 comprises a heat exchange unit 12, a valve arrangement 14, a first fluid inlet conduit 16, a second fluid inlet conduit 18, and a fluid outlet conduit 20. The apparatus is arranged to heat or cool air from an external source (such as ambient air or outdoors air) and to supply the air into the room. Accordingly, the heat exchange unit 12 is arranged to heat or cool air which passes through the apparatus 10 prior to supplying the air into the room. The heat exchange unit may comprise any suitable arrangement for transferring heat between one fluid and another. In this embodiment, the heat exchange unit 12 comprises a heat exchanger 22 arranged in an air flow path of the apparatus 10 so as to heat or cool incoming air passing through the heat exchange unit 12. The heated or cooled air is subsequently directed into the room. In this embodiment, the apparatus 10 comprises a fan 25 arranged to drive air through the heat exchanger 22 and towards the room. The apparatus 10 also comprises a filtering arrangement 35 for filtering airflow through the apparatus 10. The heat exchanger 22 comprises an airflow pathway and a coolant fluid pathway and is configured to transfer heat between the air and the coolant. The heat exchanger 22 is arranged to receive fluid coolant. An inlet 24 of the heat exchanger 22 is in fluid communication with the valve arrangement 14. The valve arrangement 14 is arranged to control flow of coolant into the heat exchange unit 12. In particular, the valve arrangement 14 is arranged to direct coolant to the heat exchanger 22 from either the coolant supply path 4 or the coolant return flow path 6, as described further below. The first fluid inlet conduit 16 extends between the coolant supply path 4 and the valve arrangement 14. The second fluid inlet conduit 18 extends between the coolant return flow path 6 and the valve arrangement 14. In this way, the first fluid inlet conduit 16 is arranged to provide a fluid flow path between the coolant supply path 4 and the valve arrangement 14 and the second fluid inlet conduit 18 is arranged to provide a fluid flow path between the coolant return flow path 6 and the valve arrangement 14. An outlet 26 of the heat exchanger 22 is in fluid communication with the fluid outlet conduit 20. The fluid outlet conduit 20 extends between the heat exchanger 22 and the coolant return flow path 6 to provide a fluid flow path between the heat exchanger 22 and the return fluid flow path 6. In this way the fluid outlet conduit 20 is arranged to return coolant to the coolant return flow path 6 from the heat exchanger 22. In this embodiment, the valve arrangement 14 comprises a three-way valve 28 (for example a three-port bypass valve). A first port or inlet 30 of the valve 28 is in fluid communication with the first fluid inlet conduit 16. A second port or inlet 32 of the valve 28 is in fluid communication with the second fluid inlet conduit 18. An outlet 34 of the valve 28 is in fluid communication with the inlet 24 of the heat exchanger 22. The valve 28 is provided with an actuator 36 for operating the valve 28. In this embodiment, the actuator 36 comprises a motorised actuator. In other embodiments, the actuator may comprise on or more solenoids, hydraulics actuators, or other suitable means for operating the valve. The valve 28 is switchable between a first configuration, in which fluid communication is open between the first port 30 and the outlet 34 of the valve 28, and a second configuration in which fluid communication is open between the second port 32 and the outlet 34 of the valve 28. Accordingly, in the first configuration (as shown in Figure 1), coolant is directed to flow from the first fluid inlet conduit 16 to the heat exchanger 22. In the second configuration (as shown in Figure 2), coolant is directed to flow from the second fluid inlet conduit 18 to the heat exchanger 22. With this arrangement, with the valve 28 in the first configuration, chilled coolant is directed to flow from the coolant supply path 4 to the heat exchanger 22, so that ambient air passing through the heat exchange unit 12 may be cooled, to provide cooled air to the room. With the valve 28 in the second configuration, spent coolant (which may be at an elevated temperature compared to a temperature of the ambient air, and / or to a temperature of air in the room) is directed to flow from the coolant return flow path 6 to the heat exchanger 22. In this case, ambient air passing through the heat exchange unit 12 may be heated, before being provided to the room. Accordingly, the apparatus 10 may be operated in a first, cooling configuration or cooling mode (corresponding to the valve 28 being in the first configuration) or in a second, heat recovery configuration or heat recovery mode (corresponding to the valve 28 being in the second configuration). It will be appreciated that the valve arrangement may comprise any suitable arrangement for directing coolant flow from the coolant supply path or the coolant return flow path to the heat exchange unit. For example, the valve arrangement may comprise a single valve or a plurality of valves. In this embodiment, the apparatus 10 further comprises a pump 32 arranged in-line with the second fluid inlet conduit 18. The pump 32 is arranged to pump coolant from the coolant return flow path 6 through the second fluid inlet 18 conduit to the heat exchanger 22. The apparatus may comprise one or more stop valves or shutoff valves to allow or prevent fluid flow in parts of the apparatus 10. In the present embodiment, a first stop valve 38 is arranged in the first fluid inlet conduit 16 to prevent or allow fluid flow between the coolant supply path 4 and the three-way valve 28. A second stop valve 40 is arranged in the second fluid inlet conduit 18 between the pump 32 and the three-way valve 28 to prevent or allow fluid flow between the pump 32 and the three-way valve 28. A third stop valve 42 is arranged in the second fluid inlet conduit 18 between the coolant return flow path 6 and the pump 32 to prevent or allow fluid flow between the coolant return flow path 6 and the pump 32. A fourth stop valve 44 is provided in the fluid outlet conduit 20 to prevent or allow fluid flow between the heat exchanger 22 and the coolant return flow path 6. With the arrangements described above, the apparatus 10 may be used to adjust the temperature of air supplied to the room in use, which may also be referred to as tempering the air. The apparatus of the present invention is particularly suitable for providing ventilation and make-up air to a room. The present invention therefore also provides a method of adjusting the temperature of air supplied to a room such as a data hall having a fluid cooling system. The method of the present invention may be carried out using the apparatus 10 described above. The method comprises operating the apparatus in a heat recovery mode (for example in the first configuration as described above) by supplying spent coolant from the return flow path of the cooling system to a heat exchanger, thereby to heat air supplied to the room using heat recovered by the cooling system. The method may also comprise operating the heat exchanger in a cooling mode by supplying chilled coolant from a coolant supply to the heat exchanger (as described above). In the present embodiment, the chilled coolant is supplied from the coolant supply path of the cooling system. In other embodiments however, chilled coolant may be supplied from a source separate from the cooling system. In use, the apparatus 10 may be operated in the cooling configuration or in the heat recovery configuration depending on whether it is required to cool or heat the air to be supplied to the room. Ambient air is driven through the filter 35 and through the heat exchange unit 12 by the fan 25 and is heated or cooled by the heat exchanger 22. A direction of airflow through the heat exchange unit 12 is shown by an arrow in Figures 1 and 2. As can be seen in Figure 1, in the cooling configuration, chilled coolant flows from the coolant supply path 4 to the valve 28 via the first fluid inlet conduit 16 and is directed to the heat exchanger 22. The air is therefore cooled by the heat exchanger 22 prior to being supplied to the room. As can be seen in Figure 2, in the heat recovery configuration, spent coolant flows from the coolant return flow path 6 to the valve 28 via the second fluid inlet conduit 18 and is directed to the heat exchanger 22. The air is therefore heated by the heat exchanger 22 prior to being supplied to the room. Since the fluid pressure of coolant in the return fluid flow path 6 may be lower than the coolant pressure in the coolant supply path 4, in the second configuration the pump 32 may be operated to pump coolant in the second fluid inlet conduit 18 to the heat exchanger 22. The apparatus 10 may be operated in the cooling configuration or in the heat recovery configuration in dependence on a temperature of the ambient air and a temperature in the room (such as an air temperature in the room). In the present embodiment, to determine whether to operate the apparatus in the heat recovery mode or the cooling mode, a temperature in the room is determined and a temperature of ambient air entering the apparatus 10 is determined. If the ambient air temperature and the room air temperature are above the predetermined target temperature for the room, then the apparatus 10 is operated in the cooling configuration, thereby cooling the ambient air in order to maintain the predetermined target room temperature. If the ambient air temperature and the room air temperature are below the predetermined target temperature for the room, then the apparatus 10 is operated in the heat recovery configuration, thereby heating the ambient air so as to maintain the predetermined target temperature. It will be appreciated that, in the heat recovery configuration, waste heat carried by the spent coolant in the coolant return flow path 6 is recovered and used to heat the air supplied to the room. The recovery of heat in this way therefore allows air to be heated in a more energy-efficient manner compared to prior art heating arrangements such as resistive electric heaters. It will be appreciated that in some embodiments, the heat exchange unit may comprise more than one heat exchanger. For example the heat exchange unit may comprise two heat exchangers and the valve arrangement may be arranged to direct chilled coolant to a first heat exchanger in the first configuration and to direct spent coolant to a second heat exchanger in the second configuration. With the arrangements described above, the apparatus of the present invention does not require an auxiliary heating arrangement or auxiliary source of energy in order to heat the air. Heat recovered from equipment in the room can therefore be used to adjust the temperature of ventilation and / or make-up air supplied to the room, which may be required at a higher temperature than air for cooling equipment in the room. For example, in a data hall, servers may be housed in server racks or cabinets, which may be locally cooled by the fluid cooling system of the room. The fluid cooling system may be used to provide cooled air within a confined space of each server cabinet, or within an area of the room, whereas other areas of the room may be maintained at a higher temperature and / or may require higher turnover of air to maintain air quality for personnel. Accordingly, the apparatus of the present invention may be used to provide ventilation or make-up air to a data hall at a different temperature to a temperature of cooled air provided by the cooling system for cooling the equipment in the data hall. The apparatus of the present invention may be implemented as an air handling unit, or as a module for use with an existing air-handling unit. In some examples, the apparatus may be retrofitted to an existing air-handling unit and / or connected to an existing fluid cooling system in order to provide the ability to recover heat from the cooling system.

Claims

1. Apparatus for adjusting the temperature of air supplied to a room, the apparatus being connectable in fluid communication with a fluid cooling arrangement for cooling electronic equipment, said cooling arrangement comprising a coolant supply path for supplying chilled coolant to the fluid cooling arrangement and a coolant return flow path for returning spent coolant from the fluid cooling arrangement, wherein the apparatus comprises:a heat exchange unit configured to heat or cool incoming air prior to supplying the air to said room, and the heat exchange unit being connectable in fluid communication with the fluid cooling arrangement;wherein the apparatus is switchable between a first configuration, in which the apparatus is configured to direct chilled coolant from a coolant supply to the heat exchange unit, thereby to cool the air supplied to the room, and a second configuration in which the apparatus is configured to direct spent coolant from the coolant return flow path to the heat exchange unit, thereby to heat the air supplied to the room using the spent coolant from the fluid cooling arrangement.

2. Apparatus according to Claim 1, in which, when the apparatus is in the first configuration, the heat exchange unit is arranged to receive coolant from the coolant supply path of the fluid cooling arrangement.

3. Apparatus according to Claim 1 or Claim 2, in which an outlet of the heat exchange unit is in fluid communication with the coolant return flow path, thereby to return coolant from the heat exchange unit to the coolant return flow path.

4. Apparatus according to any preceding claim, configured to adjust the temperature of air supplied to a room in which the electronic equipment is located, such that heat recovered from the electronic equipment by the fluidcooling arrangement is used to heat the air supplied to the room.

5. Apparatus according to any preceding claim, configured to switch to the second configuration upon a temperature in the room falling below a predetermined temperature.

6. Apparatus according to any preceding claim, configured to switch to the second configuration upon a temperature of air entering the apparatus falling below a predetermined temperature.

7. Apparatus according to any preceding claim, comprising a valve arrangement connectable in fluid communication with the coolant supply path and the coolant return flow path and connected in fluid communication with an inlet of the heat exchange unit, wherein, in the first configuration, the valve arrangement is configured to direct coolant to flow from the coolant supply path to the heat exchange unit and in the second configuration, the valve arrangement is configured to direct spent coolant to flow from the coolant return flow path to the heat exchange unit.

8. Apparatus according to Claim 7, in which, in the first configuration the valve arrangement blocks coolant flow from the coolant return flow path to the heat exchange unit and in the second configuration, the valve arrangement blocks coolant flow from the coolant supply path to the heat exchange unit.

9. Apparatus according to any preceding claim, in which the heat exchange unit comprises a heat exchanger having a fluid flow path and in which, in the first configuration, chilled coolant is directed to flow through the fluid flow path and in the second configuration, spent coolant is directed to flow through the fluid flow path.

10. Apparatus according to any preceding claim, comprising a pump arranged to pump coolant from the coolant return flow path to the heat exchange unit.

11. Apparatus according to any preceding claim, comprising a fan arranged to move air through the heat exchange unit and into the room.

12. Apparatus according to Claim 11, configured to provide make-up air into the room.

13. A heat recovery system comprising apparatus according to any preceding claim and comprising the fluid cooling arrangement, in which the heat exchange unit is connected in fluid communication with the fluid cooling arrangement such that, in the first configuration, the heat exchange unit is arranged to receive chilled coolant from the coolant supply path, thereby to cool incoming air, and in the second configuration the heat exchange unit is arranged to receive spent coolant from the coolant return flow path, thereby to heat incoming air using the spent coolant from the fluid cooling arrangement.

14. A heat recovery system according to Claim 13, comprising two or more of the apparatus of any of Claims 1 to 12.

15. A room comprising the apparatus of any of Claims 1 to 12, or the heat recovery system of Claim 13, and wherein the room comprises a data hall.

16. An air-handling unit comprising apparatus according to any of Claims 1 to 12.

17. A method for adjusting the temperature of air supplied to a room, the methodcomprising:providing a heat exchange unit arranged to adjust the temperature of the air supplied to the room, the heat exchange unit being connectable in fluid communication with a fluid cooling arrangement for cooling electronic equipment, said fluid cooling arrangement having a coolant supply path for supplying chilled coolant to the fluid cooling arrangement and a coolant returnflow path for returning spent coolant from the fluid cooling arrangement; and, operating the heat exchange unit in a heat recovery configuration by directing spent coolant from the coolant return flow path to the heat exchange unit, thereby to heat the air supplied to the room.

18. The method of Claim 17, comprising operating the heat exchange unit in a cooling configuration by directing coolant from the coolant supply path to the heat exchange unit, thereby to cool the air supplied to the data hall.

19. The method of Claim 17 or Claim 18, comprising determining a temperature in the room and directing coolant to the heat exchange unit from the coolant return flow path in response to the determined temperature falling below a predetermined temperature.

20. The method of any of Claims 17 to 19, comprising determining a temperature of incoming air supplied to the heat exchange unit and directing spent coolant to the heat exchange unit from the coolant return flow path in response to the determined temperature of said incoming air falling below a predetermined temperature.

21. The method of any of Claims 17 to 20, comprising returning coolant from the heat exchange unit to the coolant return flow path.

22. The method of any of Claims 17 to 21, comprising providing a heat exchange unit arranged to adjust the temperature of the air supplied to the room in which the electronic equipment is located, such that heat recovered from the electronic equipment by the fluid cooling arrangement is used to heat the air supplied to the room.

23. The method of any of Claims 17 to 22, comprising providing a valve arrangement connectable in fluid communication with the coolant supply path and the coolant return path and connected in fluid communication with aninlet of the heat exchange unit, wherein, in a cooling configuration, the valve arrangement is configured to direct coolant to flow from the coolant supply path to the heat exchange unit and in the heat recovery configuration, the valve arrangement is configured to direct spent coolant to flow from the5 coolant return flow path to the heat exchange unit.

24. The method of Claim 23, comprising retrofitting the heat exchange unit and the valve arrangement to the fluid cooling arrangement.

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