HIGH EFFICIENCY SINGLE DUCT TERMINAL UNIT
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.
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.