Apparatus and method for cooling of a substantially closed space with recirculation air
An apparatus for cooling of a substantially closed space, in particular a data center, where continuous or intermittent heat is produced by at least one heat source, with recirculation air, includes a heat exchanger with a first set of ducts and a second set of ducts, each set of ducts having an in- and outlet. The in- and outlet of the first set of ducts are connected to the space to form a first recirculation path, and the in- and outlet of the second set of ducts are connected to an environment of the space to form a second recirculation path. The heat exchanger is a plate heat exchanger.
1. An apparatus for cooling of a substantially closed space where continuous or intermittent heat is produced by at least one heat source, with recirculation air, comprising a heat exchanger with a first set of ducts and a second set of ducts, each set of ducts having an in- and outlet, wherein the in- and outlet of the first set of ducts are connected to the space to form a first recirculation path, the in- and outlet of the second set of ducts are connected to an environment of the space to form a second recirculation path, and wherein the heat exchanger is a plate heat exchanger, and wherein the apparatus further comprises a mixing valve to allow heated air to flow from the outlet of the second set of ducts through the mixing valve to the inlet of the second set of ducts.
2. The apparatus according to claim 1 comprising a first flow circulation system to circulate air along the first recirculation path, wherein preferably the first flow circulation system divides at least a part of the first recirculation path into multiple parallel first recirculation sub-paths, at least two first recirculation sub-paths having an air displacement device and a closing valve to close the corresponding first recirculation sub-path.
3. The apparatus according to claim 1 , comprising a second flow circulation system to circulate air along the second recirculation path, wherein preferably the second flow circulation system divides at least a part of the second recirculation path into multiple parallel second recirculation sub-paths, at least two second recirculation sub-paths having an air displacement device and a closing valve to close the corresponding second recirculation sub-path.
4. The apparatus according to claim 3 comprising a conduit to connect the second recirculation path downstream of an air displacement device with the space to apply overpressure to the space.
5. The apparatus according to claim 4 , wherein the conduit is provided with a control valve to control the applied overpressure.
6. The apparatus according to claim 1 , wherein the apparatus comprises a control device configured to control an air flow in the first recirculation path based on a pressure difference.
7. The apparatus according to claim 1 comprising a control device configured to control an air flow in the second recirculation path based on a temperature in the space.
8. The apparatus according to claim 1 comprising closing means to close at least one duct of the first set of ducts and at least one corresponding duct of the second set of ducts.
9. The apparatus according to claim 8 comprising a control device configured to control the closing means based on an air flow through the first set of ducts and/or the second set of ducts.
10. The apparatus according to claim 1 comprising a perforated or porous plate before the inlet of the first set of ducts of the plate heat exchanger, said plate being arranged to provide a uniform flow to the inlet of the first set of ducts.
11. The apparatus according to claim 1 comprising an active cooling device having an evaporator to extract heat from an air flow, a condenser to add heat to an air flow, and a pump being arranged to pump a medium around from the condenser to the evaporator and back in order to transport the extracted heat from the evaporator to the condenser, the condenser being located in the second recirculation path downstream of the second set of ducts, and the evaporator being located in the first recirculation path downstream of the first set of ducts.
12. The apparatus according to claim 11 , wherein the evaporator is arranged integral with the outlet of the first set of ducts.
13. The apparatus according to claim 11 comprising a bypass around the evaporator, said bypass comprising a bypass valve to open and close the bypass.
14. The apparatus according to claim 1 , wherein the outlet of the first set of ducts is connected to the space via a conduit which has only rounded corners.
15. The apparatus according to claim 14 , wherein the rounded corners have a parabolic shape.
16. A data centre comprising a number of apparatuses according to claim 1 .
17. A method for cooling of a substantially closed space where continuous or intermittent heat is produced by at least one heat source, with recirculation air, by supplying heated recirculation air from the space to a first set of ducts of a heat exchanger and supplying air from an environment of the space to a second set of ducts of a heat exchanger, wherein the heat exchanger is a plate heat exchanger, and wherein heated air flows from an outlet of the second set of ducts through a mixing valve to an inlet of the second set of ducts.
18. The method according to claim 17 , wherein the space is divided into a cold section and a warm section by substantially air tight dividing means, the cold section being connected to an outlet of the first set of ducts, the warm section being connected to an inlet of the first set of ducts, and the dividing means being provided with openings connecting the cold section and the warm section at a location of the at least one heat source, and wherein an air flow through the first set of ducts is controlled based on a pressure difference between the cold section and the warm section.
19. The method according to claim 17 , wherein an air flow through the second set of ducts is controlled based on a temperature in the space.