Hydronic rooftop cooling systems

• US 20050056042A1
• Filed: 07/07/2004
• Published: 03/17/2005
• Est. Priority Date: 09/12/2003
• Status: Active Grant

• Current Assignee: Davis Energy Group, Inc.
• Original Assignee: Davis Energy Group, Inc.
• Inventors: Bourne, Richard C., Berman, Mark J., Lee, Brian Eric
• Granted Patent: US 7,322,205 B2
• Time in Patent Office: Days
• US Class Current: 62/310
• CPC Class Codes: F24F 1/0007 Indoor units, e.g. fan coil units self-contained units F24F1/02
• CPC Class Codes: F24F 1/0043 characterised by mounting arrangements
• CPC Class Codes: F24F 12/006 using an air-to-air heat exchanger F24F12/002 takes precedence
• CPC Class Codes: F24F 2012/007 using a by-pass for bypassing the heat-exchanger
• CPC Class Codes: F24F 3/044 Systems in which all treatment is given in the central station, i.e. all-air systems
• CPC Class Codes: F24F 5/0035 using evaporation
• CPC Class Codes: F28D 5/00 Heat-exchange apparatus having stationary conduit assemblies for one heat-exchange medium only, the media being in contact with different sides of the conduit wall, using the cooling effect of natural or forced evaporation
• CPC Class Codes: Y02B 30/54 Free-cooling systems
• CPC Class Codes: Y02B 30/56 Heat recovery units
• CPC Class Codes: Y10S 62/16 Roof and ceiling located coolers

Abstract

A roof top cooling unit has an evaporative cooling section that includes at least one evaporative module that pre-cools ventilation air and water; a condenser; a water reservoir and pump that captures and re-circulates water within the evaporative modules; a fan that exhausts air from the building and the evaporative modules and systems that refill and drain the water reservoir. The cooling unit also has a refrigerant section that includes a compressor, an expansion device, evaporator and condenser heat exchangers, and connecting refrigerant piping. Supply air components include a blower, an air filter, a cooling and/or heating coil to condition air for supply to the building, and optional dampers that, in designs that supply less than 100% outdoor air to the building, control the mixture of return and ventilation air.

Claims

1. A packaged cooling device for conditioning air within a conditioned space, comprising:

a housing enclosing the following elements;

a refrigerant loop including a compressor, a condenser, and a direct-expansion evaporator;

a first air mover that moves outside air through the direct-expansion evaporator and into the conditioned space in a first flow direction;

an indirect evaporative cooling section disposed upstream of the direct-expansion evaporator in the first flow direction, the indirect evaporative section comprising;

a plurality of barriers that define dry passages and wet passages;

a water distribution system that recirculates water to cool the condenser and to evaporatively cool the wet passages; and

a second air mover that moves inside air from the conditioned space through the wet passages and discharges the inside air outside, the second air mover moving the inside air in a second flow direction;

wherein the elements are arranged in the housing such that;

the dry passages indirectly cool outside air by conductive contact with the wet passages through the barriers before the outside air is conditioned by the direct-expansion evaporator,

the water distribution system directly cools the condenser, and

water flows from the condenser to the wet passages.

2. The device of claim 1, wherein the barriers are parallel vertical plates that define alternating dry and wet passages.

3. The device of claim 1, wherein the first air mover is located upstream in the first flow direction of the dry passages and air moved through the dry passages is delivered to the conditioned space as supply air.

4. The device of claim 1, wherein the housing penetrates a roof of the conditioned space and the first and second air movers are located above the roof and the direct-expansion evaporator extends below the roof.

5. The device of claim 1, wherein the second air mover exhausts air from the conditioned space through the wet passages.

6. The device of claim 4, wherein the compressor is located above the roof.

7. The device of claim 1, wherein the first air mover is located downstream of the evaporator, and a first outside air portion moved through the dry passages is delivered to the conditioned space as ventilation air, and a second outside air portion moved through the dry passages moves through the wet passages.

8. The device of claim 7, wherein the second air mover exhausts air from the conditioned space through the wet passages.

9. The device of claim 1, wherein the first air mover is located downstream of the direct-expansion evaporator, and further comprising a damper including a first damper position that directs a first air portion moved through the dry passages to be delivered through the direct-expansion evaporator to the conditioned space as ventilation air, and a second damper position that directs a second air portion moved through the dry passages to move through the wet passages.

10. The device of claim 1, wherein the first air mover is located downstream of the direct-expansion evaporator, and further comprising a damper, wherein the damper has first damper positions that direct a first air portion from the dry passages to be delivered to the conditioned space as ventilation air, and a first portion of building exhaust air into the wet passages;

and second damper positions that prevent the first air portions from the dry passages and the first portion of building exhaust air from entering the conditioned space and the wet passages, so that only building return air is delivered to the conditioned space, and only air from the dry passages enters the wet passages.

11. The device of claim 1, wherein the indirect evaporative cooling section comprises a vertical counter flow evaporative cooler having:

a first air stream in the first flow direction that flows into the dry passages and flows downward through the dry passages; and

a second air stream in the second flow direction that flows from an area below the barriers into the wet passages, and flows upward through the wet passages.

12. The device of claim 1, wherein the housing penetrates a roof of the conditioned space and the second air mover, the compressor, and the condenser are located above the roof, and the direct-expansion evaporator and the first air mover extend below the roof.

13. The device of claim 12, wherein the first air mover is positioned for removal and service from the roof without requiring removal of the indirect evaporative cooling section, the second air mover, or the compressor.

14. The device of claim 1, further comprising a heater disposed in the housing having a furnace section that heats supply air.

15. The device of claim 14, wherein the heater is a hydronic heater comprising a water heating device, a hydronic heating coil, a circulating pump, and connecting piping for circulating heated water through a heating coil, the heating coil disposed in a return air stream to heat building air recirculated through the device.

16. The device of claim 1, further comprising a controller that operates a valve to direct water from the water distribution system through a thermal storage medium before entering the wet passages.

17. The device of claim 16, wherein the controller directs water through the thermal storage medium and operates the water distribution system and the second air mover to cool the thermal storage medium.

18. The device of claim 17, wherein the thermal storage medium is an element of a building.

19. The device of claim 18, wherein the thermal storage element is concrete.

20. A packaged cooling device for conditioning air within a conditioned space, comprising:

a housing enclosing the following elements;

a refrigerant loop including a compressor, a condenser, and a direct-expansion evaporator;

a first air mover that moves air through a conditioned space;

an evaporative condenser cooling section having an air inlet to receive outside air;

an indirect evaporative cooling section having an air inlet to receive outside air, the indirect evaporative cooling section comprising a plurality of barriers that define dry passages and wet passages for cooling the outside air;

at least one water distribution system that provides water to evaporatively cool the wet passages of the indirect evaporative cooling section and the evaporative condenser cooling section; and

a second air mover that moves air in parallel paths through the wet passages of the indirect evaporative cooling section and the evaporative condenser cooling section, and discharges the air to the outdoors,

wherein the elements are arranged such that;

the outside air entering the indirect evaporative cooling section is indirectly evaporatively-cooled in the dry passages by conductive contact with the wet passages through the barriers to cool the outside air,

the outside air entering the evaporative condenser cooling section cools water passing through the evaporative condenser cooling section for circulation through the condenser.

21. The device of claim 20, wherein the barriers are parallel vertical plates.

22. The device of claim 20, including a hydronic heater disposed in the housing, the hydronic heater comprising a water heating device, a hydronic heating coil, a circulating pump, and connecting piping for circulating heated water through a heating coil disposed in a return air stream to heat building air recirculated through the device.

23. The device of claim 20 wherein the housing penetrates a roof of the conditioned space, and the indirect evaporative section, the evaporative condenser cooling section, the second air mover, the compressor, and the condenser extends above the roof, and the direct-expansion evaporator and the first air mover extend below the roof.

24. The device of claim 23, wherein the first air mover is positioned for removal and service from the roof without requiring removal of the indirect evaporative section, the evaporative condenser cooling section, the second air mover, or the compressor.

25. The device of claim 20, wherein the first air mover is positioned to move air in parallel paths through the dry passages of the indirect evaporative section and the direct-expansion evaporator into the conditioned space, and further comprising a damper including a first damper position that directs a first air portion through the dry passages and a second air portion through the direct-expansion evaporator, and a second damper position that prevents the flow of the first air portion.

26. The device of claim 25, wherein the first damper position directs a third air portion through the wet passages of the indirect evaporative section into the second air mover, and directs a fourth air portion through the direct-expansion evaporator into the first air mover, and the second damper position directs all building return air through the direct-expansion evaporator into the first air mover, for delivery into the conditioned space.

27. The device of claim 26, further comprising a third damper position that directs outside air to the first air mover, bypassing the dry passages of the indirect evaporative section and the direct-expansion evaporator, for delivery into the conditioned space, and that directs all building return air toward the second air mover for discharge to the outside.

28. The device of claim 20, wherein the evaporative condenser cooling section comprises a parallel plate evaporative cooler comprising a plurality of vertical plates that define indirect passages and alternating direct passages wherein the direct passages are evaporatively cooled, and the outside air enters the indirect passages, flows downward through the indirect passages, emerges from the indirect passages, is drawn into the direct passages, flows upward through the direct passages, and is drawn out of the direct passages and discharged to the outside by the second air mover.

29. The device of claim 28, wherein the condenser is a refrigerant-to-water condenser and the water distribution system recirculates water from a reservoir beneath the evaporative condenser cooling section to the refrigerant-to-water condenser, to the direct passages of the evaporative condenser cooling section and to the wet passages of the indirect evaporative section, and all recirculated water drains to the reservoir under the condenser cooling section.

30. The device of claim 29, wherein the water distribution system directs a first recirculated water stream from the reservoir through the refrigerant-to-water condenser to the direct passages, and a second recirculated water stream from the reservoir to the wet passages.

31. The device of claim 30, wherein the water distribution system includes a valve to block the first recirculated water stream at times when no air is flowing through either the dry passages or the wet passages.

32. The device of claim 31, further comprising a controller that operates a valve to direct the second water stream from the reservoir through a thermal storage medium before entering the refrigerant-to-water condenser.

33. The device of claim 32, wherein the controller directs water through the thermal storage medium and operates the second air mover during prescribed time periods when the refrigerant loop is not operating, and the water is cooler than the thermal storage medium.

34. The device of claim 33, wherein the thermal storage medium is an element of a building.

35. The device of claim 34, wherein the thermal storage element is concrete.

36. The device of claim 20, wherein water that condenses on the direct-expansion evaporator flows into the water distribution system.

37. The device of claim 20, wherein water that condenses on the direct-expansion evaporator is directed into the water distribution system.

47. The device of claim 20, wherein the water distribution system includes a reservoir located below the evaporative condenser cooling section, and the housing includes cantilevered section that supports the reservoir above the roof.

38. A method of conditioning air within a conditioned space, comprising:

a. moving outside air into the space using an air mover;

b. pre-cooling the outside air in an indirect evaporative heat exchanger; and

c. moving the pre-cooled air through an evaporator coil and into the space.

39. The method of claim 38, further comprising:

recirculating water used in the indirect evaporative heat exchanger;

cooling a condenser connected to the of the evaporator coil using the recirculating water; and

selecting a rate of cooling accomplished by the evaporator coil and the condenser by varying the speed of the air mover.

40. The method of claim 38, further comprising mixing the pre-cooled air with building return air and moving the mixed air through the evaporator coil.

41. The method of claim 38, further comprising collecting condensate water from the evaporator coil and moving the condensate water into the recirculating water.

42. A method of conditioning air within a conditioned space, comprising:

moving a mixture of pre-cooled outside air and building return air into the space using an air mover;

pre-cooling the outside air in an indirect evaporative heat exchanger; and

moving the building return air through an evaporator coil before mixing the building air with the pre-cooled outside air.

43. The method of claim 42, further comprising:

recirculating water used in the evaporative heat exchanger; and

moving the recirculating water to contact a condenser associated with the evaporator coil.

44. The method of claim 42, further comprising operating the air mover and the indirect evaporative heat exchanger to cool the space by pre-cooling the outside air without operating at least one of the evaporator coil and the condenser.

45. The method of claim 43, further comprising operating the air mover, the indirect evaporative heat exchanger, and the condenser and evaporator coil to cool the outside air and the return air, and cooling the condenser using the indirect evaporative heat exchanger.

46. The method of claim 42, further comprising collecting condensate water from the evaporator coil and moving the condensate water into the recirculating water.