1. Heat Pipe Heat Recovery System Ashley Archibald Thomas Dean Christopher Johnson Tyler Norbut Daniela Wagus

2. Introduction to PoolPak PoolPak International is a leader in the manufacture of indoor pool dehumidification equipment. NEED: Heat Pipe for Next Generation Dehumidification Equipment to pre-heat incoming air

3. How a Heat Pipe Works 1. Heat Enters (warm indoor air) 2. Refrigerant Evaporates 3. Vapor Flow upwards 4. Cool Air Enters 5. Vapor Condenses, cool air is pre-heated 6. Liquid Return via gravity Heat Pipe 1 2 3 4 5 6 6 Splitter Plate Pool

4. Project Description Develop a mathematical design tool Develop a mathematical design tool will predict heat pipe behavior (for validation) will predict heat pipe behavior (for validation) will compute heat pipe size (as design tool) will compute heat pipe size (as design tool) Build a heat pipe prototypes Build a heat pipe prototypes Develop test set-ups for prototype Develop test set-ups for prototype Evaluate test results against predicted results to validate our model Evaluate test results against predicted results to validate our model

5. Mathematical Model Prototype Design Tool Wants: Wants: Accurate in predicting the behavior of heat pipe Accurate in predicting the behavior of heat pipe Calculated vs. measured value: ± 5% Calculated vs. measured value: ± 5% User-friendly User-friendly symbolic mathematics symbolic mathematics Explanations/instructions Explanations/instructions Organized inputs according to supplier information Organized inputs according to supplier information Easily varied inputs Easily varied inputs Feasibility Feasibility Low Cost ~ $0 Low Cost ~ $0 Available or free software Available or free software Visible step-by-step procedure Visible step-by-step procedure Fast calculations: < 5 min Fast calculations: < 5 min Constraints: Constraints: Vertical, finned, continuous tube heat pipe Vertical, finned, continuous tube heat pipe Model parameters to facilitate validation through tests Model parameters to facilitate validation through tests

6. Concept Selection Manual Calcs (Paper w/Calculator) Spreadsheet Software (Excel) Symbolic Math (MathCAD) Level 1 Complexity Symbolic Math (MathCAD) Level 2 Complexity Accurate Large Error Risk User-FriendlyX Visible Step-by- Step Procedure X Fast Calculation X Low Cost FeasibilityXX Score2565 Selected to create our Mathematical Design Tool with MathCAD, employing level one complexity and assumptions

7. Mathematical Model System of equations to predict the performance of a heat pipe System of equations to predict the performance of a heat pipe Focus on internal behavior but external parameters will be used to determine internal properties Focus on internal behavior but external parameters will be used to determine internal properties Based upon assumptions to avoid internal limitations Based upon assumptions to avoid internal limitations Designed to enable validation with measurable data from Tests Designed to enable validation with measurable data from Tests

8. Mathematical Model Design Assumptions Assumptions Mass flow rates of condensed and evaporated refrigerant are equal Mass flow rates of condensed and evaporated refrigerant are equal Resistance due to fouling is negligible Temperature of Vapor = Temperature of Condensate Temperature of Evaporator Wall = Temperature of Warm Airflow Temperature gradient through pipe, energy loss due to dissimilar shear forces of two-phase flow is neglected  graduate level research Temperature gradient through pipe, energy loss due to dissimilar shear forces of two-phase flow is neglected  graduate level research When we created our mathematical model, our outputs were chosen based upon the easiest validation of our equations. To use the model as a design tool, equations can be manipulated to produce the desired outputs.

9. Mathematical Model Design Validation Inputs Validation Inputs Refrigerant and pipe properties Refrigerant and pipe properties Incoming air properties Incoming air properties Air flow rates Air flow rates Length of evaporator & condenser Length of evaporator & condenser Validation Outputs Validation Outputs Heat transferred Heat transferred Mass flow rate of refrigerant Mass flow rate of refrigerant Temperatures of outgoing air Temperatures of outgoing air Optimal volume of refrigerant Optimal volume of refrigerant Design Inputs Refrigerant and pipe properties Incoming air properties Air flow rates Desired output temperature Design Outputs Heat transferred Mass flow rate of refrigerant Optimal length of evaporator & condenser Optimal volume of refrigerant

10. Validation of Concept Step 1. Creation of Prototype Heat Pipes Step 2. Experimental prototype testing Step 3. Comparison between experimental values and mathematical model outputs In order to validate the internal behavior predicted by our mathematical model, we must evaluate the external properties of the heat pipe and find a relationship between the external and internal parameters.

11. Heat Pipe Prototypes 36 tubes, one row of coils 36 tubes, one row of coils Aluminum finned Aluminum finned Header Pipe Header Pipe 1 st Prototype total length = 52.2 in 1 st Prototype total length = 52.2 in 2 nd Prototype total length = 40.5 2 nd Prototype total length = 40.5 Refrigerant R22 used Refrigerant R22 used

12. Prototype Testing

13. Tests for Validation Tests for Validation Overall Heat pipe length Overall Heat pipe length Multiple refrigerants Multiple refrigerants Variable airflow rates Variable airflow rates Variable air temperatures Variable air temperatures Volume of refrigerant Volume of refrigerant

14. Prototype Testing Results

15. Validation Large Heat Pipe, Run #2 0.12531 kg/s in evaporator section 0.12500 kg/s in condenser section Recall: Assumption: Mass flows equal Validation:Difference 0.25%

16. Cost Analysis Other expenditures include the time Team 3, PoolPak and UD professors invested into the project. There were also costs associated with the energy and resources used during testing of the prototype.

17. Transition Plan Restructure Validation Model into Design Tool Path Forward Recommendations: Math Modeling Tool Math Modeling Tool Remove assumptions Remove assumptions Testing Testing Vary lengths of heat pipe sections Vary lengths of heat pipe sections Test a smaller header and place in warm duct Test a smaller header and place in warm duct Validation Validation Numerical Validation with commercial program Numerical Validation with commercial program

18. Acknowledgements Ken Cooper Pat Reynolds Tim Sechrist Lan Xie George Emenheiser Steve Fisher Tim Thompson Dr. Keefe Dr. Advani Dr. Wang

19. Questions???