High efficiency single duct terminal unit

Abstract

According to various embodiments, a single duct terminal unit includes an air inlet coupled to a casing that allows air to enter the casing, a heat exchanger disposed within the casing and downstream of the inlet relative to airflow entering the casing, a damper disposed downstream of the heat exchanger relative to the airflow entering the casing, the damper controlling airflow through an air outlet, and a control unit in communication with the damper, where the control unit adjusts a positioning of the damper based upon airflow through the air inlet and a requested temperature of airflow through the air outlet.

What is claimed is: 
     
         1 . A single duct terminal unit, comprising:
 an air inlet coupled to a casing that allows air to enter the casing;   a heat exchanger disposed within the casing and downstream of the inlet relative to airflow entering the casing;   a damper disposed downstream of the heat exchanger relative to the airflow entering the casing, the damper controlling airflow through an air outlet; and   a control unit in communication with the damper, wherein the control unit adjusts a positioning of the damper based upon airflow through the air inlet and a requested temperature of airflow through the air outlet.   
     
     
         2 . The single duct terminal unit of  claim 1 , wherein the air inlet is sized smaller than the air outlet. 
     
     
         3 . The single duct terminal unit of  claim 2 , wherein the air inlet and air outlet comprise a circular cross section. 
     
     
         4 . The single duct terminal unit of  claim 2 , wherein a diameter of the air outlet is approximately 12.5% to 25% larger than a diameter of the air inlet. 
     
     
         5 . The single duct terminal unit of  claim 1 , wherein the air outlet is disposed downstream of the heat exchanger relative to airflow entering the casing. 
     
     
         6 . The single duct terminal of  claim 1 , wherein the air outlet comprises a cylindrical outlet coupled to the casing, and the damper is disposed within the air outlet. 
     
     
         7 . The single duct terminal unit of  claim 1 , further comprising a flow sensor disposed within the air inlet or the casing, the flow sensor communicatively coupled to the control unit and configured to detect airflow through the air inlet. 
     
     
         8 . The single duct terminal unit of  claim 1 , further comprising a temperature sensor disposed within the air inlet, wherein the temperature sensor provides inlet temperature data to the control unit. 
     
     
         9 . The single duct terminal unit of  claim 1 , further comprising an outlet temperature sensor disposed within the air outlet or downstream of the air outlet, wherein the temperature sensor provides outlet temperature data to the control unit. 
     
     
         10 . The single duct terminal unit of  claim 1 , wherein the heat exchanger comprises a plurality of water coils that utilize a fin and tube construction. 
     
     
         11 . The single duct terminal unit of  claim 1 , wherein the control unit adjusts the positioning of the damper in response to a requested temperature from a thermostat associated with an environment receiving airflow from the air outlet. 
     
     
         12 . A method comprising:
 receiving, in a control unit, a requested temperature associated with an environment;   determining, in the control unit, a measure of airflow into an air inlet of a single duct terminal unit based on data from an airflow sensor;   determining, in the control unit, a temperature of airflow into the air inlet;   determining, in the control unit based on the measure of the airflow and the temperature, a setting for a heat exchanger disposed downstream of the air inlet and upstream of a damper;   determining, in the control unit based on the measure of the airflow, the temperature, and the setting for the heat exchanger, a damper position of a damper located downstream of the air inlet and the heat exchanger; and   causing, by the control unit, the damper to be position at the damper position and the heat exchanger to activate according to the setting for the heat exchanger.   
     
     
         13 . The method of  claim 12 , wherein the damper is positioned within an air outlet of the single duct terminal unit. 
     
     
         14 . A method of  claim 12 , wherein the control unit determines the damper position and the setting for the heat exchanger based on temperature data from a temperature sensor in the air outlet or downstream of the damper.