ADVANCES IN MODELING OF GROUND-SOURCE HEAT PUMP

3,96

MB

SYSTEMS

168

stron

6384

ID

Oklahoma State University

1999

rok

TABLE OF CONTENTS

Chapter

1. Introduction1

1.1. Overview of Ground-Source Heat Pump Systems 1

1.1.1. Ground-Water Heat Pump Systems .4

1.1.2. Ground-Coupled Heat Pump Systems5

1.1.2.1. Vertical Ground-Coupled Heat Pump Systems6

1.1.2.2. Horizontal Ground-Coupled Heat Pump Systems 10

1.1.3. Surface-Water Heat Pump Systems . 12

1.1.4. Standing Column Well Systems 13

1.2. Thesis Objectives and Scope 15

1.3. The Overall Modeling Approach 17

2. A Preliminary Assessment of the Effects of Ground-Water Flow on Closed-Loop Ground-Source

Heat Pump Systems . 20

2.1. Introduction . 20

2.2. Coupled Ground-Water Flow and Heat Transport 24

2.2.1. Ground-Water Flow 24

2.2.2. Heat Transport in Ground Water . 26

2.2.3. Typical Hydraulic and Thermal Properties of Soils and Rocks 27

2.2.4. Conduction versus Advection in Geologic Materials . 30

2.2.5. Numerical Ground-Water Flow and Heat Transport Models 33

2.3. The Numerical Model 37

2.3.1. Model Description. 37

2.3.2. The Finite Element Mesh 38

2.3.3. Boundary Conditions. 39

2.3.4. Validation of the Numerical Model . 41

2.4. Results and Discussion. 43

2.4.1. Single-Borehole Simulations . 43

2.4.2. Simulated In-Situ Thermal Conductivity Tests 45

2.4.3. Borehole Field Simulations . 49

2.5. Concluding Remarks and Recommendations for Future Work . 57

3. A Model for Simulating the Performance of a Shallow Pond as a Supplemental Heat Rejecter with

Closed-Loop Ground-Source Heat Pump Systems 60

3.1. Introduction . 60

3.2. Heat Transfer In Ponds 61

3.2.1. General Overview . 61

3.2.2. Existing Pond and Lake Models 62

3.3. Experimental Methods . 66

3.3.1. Pond Description and Data Collection . 66

3.3.2. Weather Instrumentation and Data Collection 67

3.4. Model Development 68

3.4.1. Governing Equations. 68

3.4.1.1. Solar Radiation Heat Gain 69

3.4.1.2. Thermal Radiation Heat Transfer 71

3.4.1.3. Convection Heat Transfer at the Pond Surface 72

3.4.1.4. Heat Transfer to the Ground . 75

3.4.1.5. Heat Transfer Due to Ground Water Seepage . 76

3.4.1.6. Heat Transfer Due to Evaporation. 77

3.4.1.7. Heat Transfer Due to the Heat Exchange Fluid . 79

3.4.1.8. Solving the Overall Energy Balance Equation. 83

3.4.2. Computer Implementation. 84

3.5. Results and Discussion. 87

3.5.1. Model Comparison to Experimental Results With No Heat Rejection 87

3.5.2. Model Comparison to Experimental Results With Heat Rejection . 89

3.5.3. Model Application 92

3.6. Concluding Remarks and Recommendations for Future Work . 97

4. A Model for Simulating the Performance of a Pavement Heating System as a Supplemental Heat

Rejecter with Closed-Loop Ground-Source Heat Pump Systems. 99

4.1. Introduction . 99

4.2. Heat Transfer In Pavement Slabs . 100

4.3. Experimental Methods . 101

4.3.1. Test Slab Description and Data Collection. 101

4.3.1.1. Bridge Deck Test Section . 101

4.3.1.2. Parking Lot Test Section. 104

4.3.2. Weather Instrumentation and Data Collection 105

4.4. Model Development 106

4.4.1. Governing Equations. 106

4.4.2. The Finite Difference Grid 108

4.4.3. Boundary Conditions. 108

4.4.3.1. Solar Radiation Heat Flux. 110

4.4.3.2. Thermal Radiation Heat Flux 111

4.4.3.3. Convection Heat Flux at the Pavement Surfaces . 111

4.4.3.4. Heat Flux Due to Rain and Snow 113

4.4.3.5. Heat Transfer Due to the Heat Exchange Fluid . 116

4.4.4. Computer Implementation. 118

4.5. Results and Discussion. 121

4.5.1. Model Comparison to Experimental Results With No Heat Rejection 121

4.5.2. Model Comparison to Experimental Results With Heat Rejection . 121

4.5.3. Model Application 126

4.6. Concluding Remarks and Recommendations for Future Work . 131

5. Summary and Conclusions. 133

References 140

APPENDIX A – Model and Experimental Uncertainty Analysis 145