초록 ▼

A conditioned vestibule, control system, and method are disclosed for use with a cold storage doorway that separates warm and cold sides. A heater warms an air stream discharged across the doorway by the vestibule. A control unit operates the heater to maintain an air stream temperature. The control

A conditioned vestibule, control system, and method are disclosed for use with a cold storage doorway that separates warm and cold sides. A heater warms an air stream discharged across the doorway by the vestibule. A control unit operates the heater to maintain an air stream temperature. The control unit continuously monitors the air stream temperature and operates the heater to maintain the air stream temperature in a non-saturated state based on a humidity ratio. One embodiment calculates first and second temperatures based, respectively, warm and cold side tangent lines to a psychrometric saturation curve and based on the humidity ratio. The tangent lines are based on humidity and temperature sensed on the warm and cold sides. The air stream is warmed to at least the greater of the first and second temperatures. One embodiment controls air flow to adjust the humidity ratio to more efficiently operate the vestibule.

대표청구항 ▼

1. An air curtain arrangement for a cold storage doorway, comprising: a discharge means that discharges an air stream across a doorway having a cold side and a warm side;a heater that warms the air stream;a control unit that operates the heater to maintain an air stream temperature;an air return mea

1. An air curtain arrangement for a cold storage doorway, comprising: a discharge means that discharges an air stream across a doorway having a cold side and a warm side;a heater that warms the air stream;a control unit that operates the heater to maintain an air stream temperature;an air return means that receives the air discharged across the opening; andan air stream temperature sensor that provides an air stream temperature input to the control unit;wherein the control unit continuously monitors the air stream temperature, and operates the heater to maintain the air stream temperature at the greater of (1) a first temperature represented by an intersection on a psychrometric saturation chart of a warm side tangent line to a psychrometric saturation curve and a humidity ratio line based on a humidity ratio, and (2) a second temperature represented by an intersection of a cold side tangent line to the curve and the humidity ratio line, wherein the humidity ratio is predetermined based upon an intersection of the warm and cold side tangent lines to the psychrometric saturation curve on a psychrometric saturation chart. 2. The air curtain arrangement of claim 1, further comprising warm and cold side temperature sensors that sense temperatures of the warm and cold sides, respectively, and provide inputs to the control unit, andwherein the control unit continuously monitors the warm and cold side temperatures and operates the heater based on the warm and cold side temperatures. 3. The air curtain arrangement of claim 2, further comprising warm and cold side humidity sensors that sense humidity of the warm and cold sides, respectively, and provide inputs to the control unit, andwherein the control unit continuously monitors the warm and cold side humidity and operates the heater based on the warm and cold side humidity. 4. The air curtain arrangement of claim 1, further comprising a volumetric air flow control that controls flow of the air stream to maintain the air curtain arrangement at the humidity ratio calculated based on warm and cold side tangent lines to a psychrometric saturation curve. 5. An air curtain arrangement for a cold storage doorway, comprising: means for directing a plurality of air streams across the doorway having a relatively warm side and a relatively cold side; andmeans for maintaining a temperature at the air stream based on a predetermined humidity ratio associated with the doorway, by controlling relative volumetric airflow of the plurality of air streams,wherein said means for maintaining comprises: means for determining a temperature and humidity of a warm side and a cold side of the doorway; andmeans for setting the temperature based on the temperature and humidity of the cold side and warm side by determining a first and a second temperature based, respectively, on a warm side tangent line and a cold side tangent line to a psychrometric saturation curve, and based on the humidity ratio, and setting the air stream temperature based on a greater of the first and second temperatures. 6. The air curtain arrangement of claim 5, wherein the means for maintaining comprise means for warming the air stream to the temperature, and means for controlling the means for warming. 7. The air curtain arrangement of claim 5, wherein the means for determining comprises means for sensing the humidity and temperature of the warm side and cold side during operation of the air curtain arrangement. 8. The air curtain arrangement of claim 5, wherein the means for maintaining comprises means for controlling the airflows based upon temperature and humidity of the warm and cold side and upon a barometric pressure. 9. The air curtain arrangement of claim 5, wherein the means for maintaining comprises means for controlling the relative volumetric airflows based upon an intersection point on a psychrometric saturation chart of warm and cold side tangent lines to a saturation curve, wherein the warm and cold side tangent lines are based, respectively, on air characteristics of the warm and cold sides. 10. The air curtain arrangement of claim 5, further comprising sensing the relative volumetric airflows and air characteristics during operation of the air curtain arrangement; andwherein the means for maintaining comprises means for dynamically controlling the relative volumetric airflows during the operation of the air curtain arrangement. 11. A method of controlling air stream temperature of an air curtain used in connection with an air curtain arrangement for a cold storage doorway that separates relatively warm and cold sides, the method comprising: continuously monitoring warm and cold side temperatures;determining a warm side tangent line that is tangent to a saturation curve on a psychrometric saturation chart, using the warm side temperature and a warm side humidity;determining a cold side tangent line that is tangent to the saturation curve, using the cold side temperature and a cold side humidity;determining a humidity ratio based upon an intersection point on the saturation chart of the warm and cold side tangent lines;determining a first temperature represented by an intersection of the warm side tangent line and a humidity ratio line based on the humidity ratio;determining a second temperature represented by an intersection of the cold side tangent line and the humidity ratio line;directing the air stream across the doorway; andmaintaining the air stream at the greater of the first and second temperatures. 12. The method of claim 11, further comprising controlling the humidity ratio by controlling volumetric airflow in the air curtain arrangement. 13. The method of claim 12, wherein the controlling the volumetric airflow comprises controlling volumetric airflow of the air stream relative to another air stream in the arrangement. 14. A conditioned vestibule for a cold storage doorway, comprising: first and second air curtains positioned adjacent each other, wherein the air curtains each direct an air stream across a doorway that separates a relatively warm side from a relatively cold side;one or more sensors that sense an air characteristic of at least one of the warm side and the cold side;an air stream sensor that senses an air characteristic of the air stream and provides an air stream input to the control unit; anda control unit that operates a heater to maintain the air stream of at least one of the air curtains at a temperature based on a humidity ratio of the vestibule, wherein the humidity ratio is based on the air curtains' relative volumetric airflow, wherein the control unit receives an air characteristic input from the one or more sensors and continuously monitors the air characteristic input, and operates the heater to maintain the air stream temperature based on the greater of (1) a first temperature represented by an intersection on a psychrometric saturation chart of a warm side tangent line to a psychrometric saturation curve and a humidity ratio line based on the humidity ratio, and (2) a second temperature represented by an intersection of a cold side tangent line to the curve and the humidity ratio line. 15. The vestibule of claim 14, wherein the one or more sensors comprise a temperature sensor that senses temperature on at least one of the warm and cold sides, andwherein the air stream sensor senses the air stream temperature. 16. The vestibule of claim 14, wherein the first air curtain is positioned near the relatively cold side, and the second air curtain is positioned near the relatively warm side, andwherein the control unit maintains the air stream temperature of the first air curtain. 17. The vestibule of claim 16, further comprising one or more sensors that sense temperature and humidity on the warm side and the cold side and provide inputs to the control unit, andwherein the warm side tangent line and cold side tangent line are based, respectively, on the warm and cold side temperature and humidity sensed by the at least one sensor. 18. The vestibule of claim 14, wherein the control unit controls relative airflow of at least one of the air streams to control the humidity ratio. 19. The vestibule of claim 18, wherein the control unit controls the relative airflow to maintain the humidity ratio based upon air characteristics of warm and cold sides. 20. A method of maintaining an air stream temperature of an air curtain in a doorway between a relatively cold side and a relatively warm side, the method comprising: continuously monitoring a temperature and a humidity of a relatively warm and a relatively cold side of a doorway comprising an air curtain that directs an air stream across the doorway;determining warm and cold side tangent lines based, respectively, on the warm and the cold side temperature and humidity, andmaintaining the air stream at a temperature above the greater of first and second temperatures corresponding, respectively, to intersections on a psychrometric saturation chart of the warm and cold side tangent lines with a humidity ratio line based on a predetermined humidity ratio of mixed air in the air curtain. 21. A control unit for controlling temperature of an air stream directed across a doorway by one or more air curtains that are part of an air curtain arrangement positioned across the doorway separating relatively warm and cold air masses, the control unit comprising: a processor; anda storage arrangement that stores computer-executable instructions for execution by the processor to control operation of the air curtain arrangement, wherein the instructions comprise instructions for: continuously monitoring an air characteristic of at least one the relatively warm and cold air masses,continuously monitoring an air stream temperature, andoperating a heater to warm the air stream temperature based on the greater of (1) a first temperature defined by an intersection of a warm side tangent line and a humidity ratio line, and (2) a second temperature defined by an intersection of a cold side tangent line and the humidity ratio line. 22. An apparatus for forming an air stream across a doorway between areas of relatively cool and warm air masses including a supply air plenum with an outlet aperture at a first side of the doorway, a return air duct with an inlet aperture at a second side of the doorway and an intermediate air duct extending between the supply plenum and return air duct, the apparatus comprising: an air mover for moving an air stream across the doorway into the inlet aperture to the return air duct through the intermediate air duct to the supply air plenum and out of the outlet aperture;a heater in thermal communication with the air stream for warming the air stream;a control unit controlling the operation of the heater;a first air sensor located in one of the relatively cool and warm air areas providing an air characteristic input to the control unit; anda second air sensor located in contact with the air stream providing an air stream characteristic input to the control unit;wherein the control unit continuously monitors the air characteristic input and the air stream characteristic input and operates the heater to maintain the temperature of the air stream at a temperature that is at least as great as the greater of (1) a first temperature defined by an intersection of a warm side tangent line and a humidity ratio line, and (2) a second temperature defined by an intersection of a cold side tangent line and the humidity ratio line. 23. An apparatus for forming at least two air streams across a doorway between areas of relatively cool and warm air masses using first and second air curtains, each including a supply air plenum with an outlet aperture at one side of the doorway, a return air duct with an inlet aperture at another side of the doorway and an intermediate air duct extending between the supply plenum and return air duct, and an air mover for moving an air stream across the doorway into the air curtain's respective inlet aperture to the return air duct through the intermediate air duct to the supply air plenum and out of the outlet aperture, the apparatus comprising: a heater in thermal communication with the air stream from at least one of the air curtains for warming the air stream of the particular air curtain;a control unit controlling the operation of the heater;a first air sensor located in one of the relatively cool and warm air areas providing an air characteristic input to the control unit; anda second air sensor located in contact with the air stream providing an air stream characteristic input to the control unit;wherein the control unit continuously monitors the air characteristic input and the air stream characteristic input and operates the heater to maintain the temperature of the air stream at the greater of (1) a first temperature defined by an intersection of a warm side tangent line and a humidity ratio line, and (2) a second temperature defined by an intersection of a cold side tangent line and the humidity ratio line. 24. A method of maintaining a non-saturated air stream across a doorway between areas of relatively cool and warm air masses so as to prevent condensation and the formation fog or frost at the doorway, wherein the air stream is generated by an air curtain including a supply air plenum with an outlet aperture at a first side of the doorway through which an air stream is forced across the doorway to an inlet aperture of a return air duct at a second side of the doorway, the method comprising: monitoring continuously the condition of the air stream and the condition of at least one of the relatively cool and warm ambient air areas; andconditioning the air stream to maintain the temperature and humidity of the air stream at the greater of (1) a first temperature defined by an intersection of a warm side tangent line and a humidity ratio line, and (2) a second temperature defined by an intersection of a cold side tangent line and the humidity ratio line. 25. A method of controlling air flow in an air curtain arrangement having a plurality of air curtains, the method comprising: calculating a humidity ratio for the air curtain arrangement based upon an intersection of a warm side tangent line to a psychrometric saturating curve and a cold side tangent line to the curve;adjusting relative volumetric air flow of the air curtains to maintain operation of the air curtain arrangement at the calculated humidity ratio; andmaintaining a temperature of an air stream in at least one of the air curtains at the greater of (1) a first temperature defined by an intersection of a warm side tangent line and a humidity ratio line, and (2) a second temperature defined by an intersection of a cold side tangent line and the humidity ratio line. 26. The apparatus of claim 23, wherein the control unit controls relative volumetric airflow between at least two of the air streams to adjust a humidity ratio of the apparatus. 27. The method of claim 24, wherein the conditioning further comprises controlling relative volumetric airflow between at least two of the air streams to adjust a humidity ratio of the apparatus. 28. The air curtain arrangement of claim 1, further comprising a second discharge means that discharges a second air stream across the doorway;wherein the control unit controls relative volumetric airflow as between the air stream and the second air stream to maintain operation of the air curtain based on the humidity ratio.