Liquid desiccant air conditioner modules having aerodynamic features
A three-way heat exchanger operable to transfer heat between a heat transfer fluid, a liquid desiccant, and air. The three-way heat exchanger includes an airflow inlet, an airflow outlet, and panel assemblies arranged with airflow gaps defined between adjacent panel assemblies to allow the air to flow between the airflow inlet and the airflow outlet in an airflow direction. Each panel assembly includes a frame defining a heat transfer fluid channel for channeling a flow of the heat transfer fluid through the panel assembly and a membrane positioned on the frame and defining a desiccant channel for a flow of the liquid desiccant. The frame has a leading edge proximate the airflow inlet and a trailing edge proximate the airflow outlet. The leading edges of the frames of the panel assemblies each include a leading edge aerodynamic feature.
1 . A three-way heat exchanger operable to transfer heat between a heat transfer fluid, a liquid desiccant, and air, the three-way heat exchanger comprising:
an airflow inlet and an airflow outlet; and
panel assemblies arranged with airflow gaps defined between adjacent panel assemblies to allow the air to flow between the airflow inlet and the airflow outlet in an airflow direction, each panel assembly comprising:
a frame defining a heat transfer fluid channel for channeling a flow of the heat transfer fluid through the panel assembly, wherein the frame has a leading edge proximate the airflow inlet and a trailing edge proximate the airflow outlet; and
a membrane positioned on the frame and defining a desiccant channel for a flow of the liquid desiccant;
wherein the leading edges of the frames of the panel assemblies each include a leading edge aerodynamic feature.
2 . The three-way heat exchanger of claim 1 , wherein the three-way heat exchanger is operable with a velocity of the air being between 100 feet per minutes (FPM) to 350 FPM, and the leading edge aerodynamic features operate to control pressure drop of the air in the airflow direction.
3 . The three-way heat exchanger of claim 1 , wherein the airflow gaps have a width measured between the adjacent panel assemblies, of between 1 millimeter (mm) to 20 mm and the leading edge aerodynamic features operate to control pressure drop of the air in the airflow direction.
4 . The three-way heat exchanger of claim 1 , wherein, for each panel assembly, the leading edge aerodynamic feature is an aerodynamic contour of the leading edge.
5 . The three-way heat exchanger of claim 4 , wherein, for each panel assembly, the aerodynamic contour is a rounded shape of the leading edge.
6 . The three-way heat exchanger of claim 1 , wherein, for each panel assembly, the leading edge aerodynamic feature and the frame are made integrally from one material.
7 . The three-way heat exchanger of claim 6 , wherein, for each panel assembly, the leading edge aerodynamic feature and the frame are made integrally from an injection-molded polymer material.
8 . The three-way heat exchanger of claim 1 , wherein the trailing edges of the frames of the panel assemblies include a trailing edge aerodynamic feature.
9 . The three-way heat exchanger of claim 8 , wherein, for each panel assembly, the leading edge aerodynamic feature and the trailing edge aerodynamic feature are symmetric in shape.
10 . The three-way heat exchanger of claim 1 , wherein, for each panel assembly, the frame has opposite first and second header sections and a middle section between the opposite first and second header sections, wherein the middle section defines the leading edge and the trailing edge, the leading edge and the trailing edge each extending between the header sections.
11 . The three-way heat exchanger of claim 10 , wherein, for each pair of adjacent panel assemblies, the adjacent first and second header sections are connected and the airflow gap is defined between the adjacent middle sections.
12 . The three-way heat exchanger of claim 10 , wherein, for each pair of adjacent panel assemblies, spacers are positioned between the middle sections of adjacent frames of each pair of adjacent panel assemblies, wherein the spacers are located between the heat transfer fluid channel and each of the leading edge and the trailing edge of the adjacent frames.
13 . A heating, ventilation, and air conditioning (HVAC) system comprising:
a refrigerant sub-system; and
an air treatment sub-system comprising a three-way heat exchanger operable to transfer heat between a heat transfer fluid, a liquid desiccant, and air, the HVAC system operable to circulate the heat transfer fluid between the three-way heat exchanger and the refrigerant sub-system, wherein the three-way heat exchanger comprises:
an airflow inlet and an airflow outlet; and
panel assemblies arranged with airflow gaps defined between adjacent panel assemblies to allow the air to flow between the airflow inlet and the airflow outlet in an airflow direction, each panel assembly comprising:
a frame defining a heat transfer fluid channel for channeling a flow of the heat transfer fluid through the panel assembly, wherein the frame has a leading edge proximate the airflow inlet and a trailing edge proximate the airflow outlet; and
a membrane positioned on the frame and defining a desiccant channel for a flow of the liquid desiccant;
wherein the leading edges of the frames of the panel assemblies each include a leading edge aerodynamic feature.
14 . The HVAC system of claim 13 , wherein, for each panel assembly of the three-way heat exchanger, the leading edge aerodynamic feature is an aerodynamic contour of the leading edge.
15 . The HVAC system of claim 13 , wherein, for each panel assembly of the three-way heat exchanger, the leading edge aerodynamic feature and the frame are made integrally from one material.
16 . The HVAC system of claim 13 , wherein, for each panel assembly of the three-way heat exchanger, the trailing edge of the frame includes a trailing edge aerodynamic feature.
17 . The HVAC system of claim 13 , wherein, for each panel assembly of the three-way heat exchanger, the frame has a middle section and two header sections at opposite ends of the middle section, wherein the middle section defines the leading edge and the trailing edge each extending between the header sections.
18 . A method of operating a three-way heat exchanger, the method comprising:
channeling a heat transfer fluid through panel assemblies of the three-way heat exchanger, wherein each panel assembly includes a frame defining a heat transfer fluid channel through which the heat transfer fluid is channeled;
channeling a liquid desiccant through desiccant channels of the panel assemblies defined between the frames of the panel assemblies and membranes attached to the frames;
channeling air through the three-way heat exchanger in an airflow direction, wherein the air flows through airflow gaps defined between adjacent panel assemblies; and
controlling a pressure drop of the air flowing through the airflow gaps in the airflow direction using aerodynamic features of the frames of the panel assemblies.
19 . The method of claim 18 , wherein the air is channeled through the three-way heat exchanger at a velocity between 100 feet per minute (FPM) to about 350 FPM.
20 . The method of claim 18 , further comprising maintaining a width of each airflow gap of between 1 millimeter (mm) to 20 mm while channeling the air through the three-way heat exchanger.