Positive displacement ventilation system

Abstract

A method includes inflating one or more inflatable bags from a first evacuated condition within an attic space to an inflated condition. The inflatable bags are configured such that when they are in an evacuated condition, they take up a relatively small space in the attic space to be ventilated. In the inflated condition, however, the bags have a cumulative volume much larger than the cumulative volume of the bags when in the evacuated condition, and make up a desired fraction of the volume of the attic space to be ventilated. When the bags are inflated from the evacuated condition to the inflated condition, they displace a volume of atmosphere equal to the difference between the cumulative volume of the bags in the evacuated condition and the cumulative volume of the bags in the inflated condition. The bags are then evacuated from the inflated condition to the fully evacuated condition or at least a substantially evacuated condition so as to draw ventilation air into the attic space through one or more ventilation inlets to the attic space.

1 . A method for ventilating an attic space, the method including:
 (a) inflating one or more inflatable bags from a first evacuated condition in the attic space to an inflated condition in the attic space, the one or more inflatable bags having a total volume in the inflated condition which comprises a desired fraction of the volume of the attic space so that the inflation of the one or more inflatable bags from the first evacuated condition to the inflated condition displaces a desired fraction of the atmosphere in the attic space through one or more ventilation outlets from the attic space; and   (b) evacuating the one or more inflatable bags in the attic space from the inflated condition to a second evacuated condition, the evacuation of the one or more inflatable bags drawing ventilation air into the attic space through one or more ventilation inlets to the attic space.   
     
     
         2 . The method of  claim 1  wherein evacuating the one or more inflatable bags includes applying a reduced pressure to the interior of each respective inflatable bag. 
     
     
         3 . The method of  claim 2  wherein evacuating the one or more inflatable bags includes applying an elongation force to each respective inflatable bag to elongate each respective bag along a first axis thereof and reduce a dimension of the respective bag along a second axis transverse to the first axis, the elongation force being a force exceeding a force resulting from the mass of the respective inflatable bag. 
     
     
         4 . The method of  claim 1  wherein evacuating the one or more inflatable bags includes applying an elongation force to each respective inflatable bag to elongate each respective bag along a first axis thereof and reduce a dimension of the respective bag along a second axis transverse to the first axis, the elongation force being a force exceeding a force resulting from the mass of the respective inflatable bag. 
     
     
         5 . The method of  claim 1  wherein the one or more inflatable bags are suspended within the attic space and wherein inflating the one or more inflatable bags includes raising a lower surface of each inflatable bag upwardly in the attic space. 
     
     
         6 . The method of  claim 1  wherein inflating the one or more inflatable bags and evacuating the one or more inflatable bags includes operating a blower which is connected to each of the one or more inflatable bags through a manifold. 
     
     
         7 . The method of  claim 1  wherein inflating the one or more inflatable bags includes applying positive pressure from a blower to the one or more inflatable bags through a valve structure in a first position, and wherein evacuating the one or more inflatable bags includes applying a vacuum from the blower to the one or more inflatable bags through the valve structure in a second position. 
     
     
         8 . A method for modifying the atmospheric temperature in an enclosed space, the method including:
 (a) inflating an inflatable bag from a first evacuated condition in the enclosed space to an inflated condition in the enclosed space to displace a desired fraction of an atmosphere from the enclose space, the displacement causing a portion of the atmosphere from the enclosed space to be expelled from the enclosed space through one or more outlet openings to the enclosed space, wherein the expelled atmosphere has a first physical characteristic; and   (b) evacuating the inflatable bag in the enclosed space to evacuate the inflatable bag from the inflated condition to a second evacuated condition, the evacuation of the inflatable bag drawing replacement atmosphere into the enclosed space through one or more ventilation openings to the enclosed space, wherein the replacement atmosphere has a second physical characteristic at the time it is drawn into the enclosed space, and wherein the second physical characteristic is different from the first physical characteristic.   
     
     
         9 . The method of  claim 8  wherein the first physical characteristic comprises a first temperature and the second physical characteristic comprises a second temperature. 
     
     
         10 . The method of  claim 9  wherein the second temperature is at least ten (10) degrees Fahrenheit below the first temperature. 
     
     
         11 . The method of  claim 8  wherein the enclosed space is an attic space and wherein inflating the inflatable bag and evacuating the inflatable bag is performed with a single blower device. 
     
     
         12 . The method of  claim 8  wherein the inflatable bag is suspended in the enclosed space and wherein inflating the inflatable bag includes raising a lower end of the inflatable bag to decrease the dimension of the inflatable bag along a first axis and increase the dimension of the inflatable bag along a second dimension extending transverse to the first dimension. 
     
     
         13 . The method of  claim 12  wherein evacuating the inflatable bag includes applying an elongation force at the lower end of the inflatable bag, the elongation force being a force exceeding a force resulting from the mass of the inflatable bag. 
     
     
         14 . An apparatus including:
 (a) one or more inflatable bags, each inflatable bag having a control opening;   (b) a blower;   (c) a manifold adapted to selectively connect the blower to the respective control opening of each of the one or more inflatable bags to enable the blower to impress a desired air flow through each respective control opening; and   (d) wherein the one or more inflatable bags are sized so that when they are in an inflated condition they occupy a total volume representing a desired fraction of a space to be ventilated.   
     
     
         15 . The apparatus of  claim 14  wherein manifold includes:
 (a) a bag connecting conduit; and 
 (b) a switching arrangement adapted to reside alternatively in a first condition and a second condition, the first condition connecting a fill outlet of the blower to the control opening of each of the one or more inflatable bags through the bag connecting conduit, and the second condition connecting a vacuum outlet of the blower to the inlet opening of each of the one or more inflatable bags through the bag connecting conduit. 
 
     
     
         16 . The apparatus of  claim 15  further including a controller adapted to control the operation of the blower and control the condition of the switching arrangement in response to control inputs. 
     
     
         17 . The apparatus of  claim 16  further including a pressure sensor connected to provide a pressure output indicating of the pressure in the one or more inflatable bags, and wherein the control inputs include the pressure output provided by the pressure sensor. 
     
     
         18 . The apparatus of  claim 16  further including a first temperature sensor located to provide a temperature output indicating the temperature of an atmosphere in the space to be ventilated, and wherein the control inputs include the temperature output of the first temperature sensor. 
     
     
         19 . The apparatus of  claim 18  further including a second temperature sensor located to provide a temperature output indicating the temperature of ambient atmosphere outside of the space to be ventilated, and wherein the control inputs include the temperature output of the second temperature sensor. 
     
     
         20 . The apparatus of  claim 14  wherein at least one of the one or more inflatable bags is suspended in the space to be ventilated and further including a biasing weight connected to a lower end of the at least one inflatable bag to apply an elongating force to the at least one inflatable bag, the elongating force exceeding a force resulting from the mass of the at least one inflatable bag.