Model Building for Pressure Diagnostics Simulation

Abstract

A scale model pressure building for teaching pressure diagnostics and weatherization strategies for residential and commercial building structures. The model building is designed for ease of fabrication and ease of assembly. The design allows the instructor to simulate numerous construction errors, airflow problems, air sealing strategies, and testing procedures while in a classroom setting.

1 - 55 . (canceled) 
     
     
         56 . An airflow indicator, comprising:
 a) an airflow sensor comprising a Wheatstone bridge, comprising:
 a first leg and a second leg, each leg comprising a series arrangement of a thermistor having a resistance value and a resistor having a resistance value, the resistance values of the resistors being the same, and the resistance values of the thermistors being the same when the thermistors are not exposed to air flow; 
 a first end of each thermistor being connected to a power source, 
 a first end of each resistor being connected to ground, 
 a second end of each thermistor being connected at a junction point to a second end of one of the resistors, 
 such that a voltage between the junction point of the first leg and the junction point of the second leg indicates an out of balance condition between the legs in the Wheatstone bridge; 
 the thermistors being arranged such that when the thermistors of the airflow sensor are located in a stream of air moving in a first direction, the thermistor of the first leg is at least partially shielded from airflow by the thermistor of the second leg, and when the stream of air is moving in a second direction opposite to the first direction, the thermistor of the second leg is at least partially shielded from airflow by the thermistor of the first leg, such that when the thermistors are exposed to air flow, the resistance value of the thermistor which is partially shielded from air flow is different from the thermistor which is not shielded from air flow, causing an imbalance between the legs of the Wheatstone bridge; 
   b) an amplifier having a differential input coupled to the junction points of the Wheatstone bridge, and an output having a signal proportional to a voltage difference between the junction points;   c) a microcontroller having an input coupled to the output of the amplifier and a plurality of outputs; and   d) a plurality of lights coupled to plurality of outputs of the microcontroller;   such that the microcontroller illuminates the plurality of lights in a sequence simulating a moving light, the direction and speed of the moving light being proportional to the signal at the output of the amplifier;   the direction and speed of the moving light indicates a direction and speed of airflow of the stream of moving air.   
     
     
         57 - 58 . (canceled)