INTEGRATING A GROUND LOOP HEAT EXCHANGER MODEL INTO A

1,01
MB BUILDING SIMULATION PROGRAM

214
stron

6390
ID Oklahoma State University

1994
rok

TABLE OF CONTENTS

1. Introduction 1

1.1 Overview. 1

1.2 Literature Review and Background 2

1.2.1 An Overview of Ground Loop Heat Exchangers. 2

1.2.2 Ground Loop Heat Exchanger Models 3

1.2.2.1 Line Source Model . 3

1.2.2.2 Cylindrical Source Model 5

1.2.2.3 Eskilson’s Model 6

1.2.2.4 Comparative Discussion . 8

1.2.3 The GLHEPRO Software . 9

1.2.4 The Water Loop Heat Pump System 12

1.2.5 Water Loop Heat Pump System Model 14

1.2.5.1 The Loop Model .14

1.2.5.2 Heat Pump Model 15

1.2.5.3 Central Plant 17

1.2.6 Water Loop Heat Pump File Used in BLAST 17

1.3 Objectives.18

2 Methodology and Implementation 19

2.1 Methodology 19

2.2 Modifications in the BLAST and GLHEPRO Codes 22

2.3 Testing the Modified Code 25

2.3.1 BLAST input file WLHPTEST.blin . 25

2.3.2 Discussion of the WLHPTEST results 26

3 Results and Discussion 29

3.1 Validation of Model 29

3.1.1 The Building Model in BLAST . 29

3.1.2 Validation of the Heat Pump Models 30

3.1.2.1 Calculation of Heat Pump Performance Parameters . 31

3.1.2.2 Comparing the Heat Pump Models of BLAST and GLHEPRO . 33

3.1.3 Validation of the Water Loop Models 34

3.2 Three Methods for Simulating Ground Loop Heat Pump Systems . 36

3.2.1 Comparing the New Model of BLAST with the Model of GLHEPRO. 36

3.2.2 Comparing the GLHEPRO Model with the Simple Constant Loads Model 38

3.2.3 A Summary of All Three Methods of Simulation 40

3.3 A Sample Problem 42

3.3.1 The Design Process . 42

3.3.1.1 Building Description in BLAST 44

3.2.1.2 Water Loop Heat Pump Description in BLAST 47

3.3.2.3 Ground Loop Heat Exchanger Description in GLHEPRO 54

3.3.2 Results for a One Year Simulation . 57

3.3.3 Studying Long Term Effects 60

3.3.4 Comparing the New BLAST Model Results with the Results from the Simple Constant Loads

Model . 62

3.3.5 Comparing the Ground Loop System with a Dual Duct VAV System. 63

4 Conclusions and Recommendations . 68

4.1 Summary and Conclusions 68

4.2 Recommendations . 69

References . 71

APPENDIXES 72

APPENDIX A. - STRUCTURAL DETAILS OF THE WATER LOOP HEAT PUMP SYSTEM

SUBROUTINE .73

APPENDIX B. - DETAILED EXPLANATION OF ALL CHANGES MADE IN THE CODE 86

APPENDIX C - A SUMMARY OF THE MANUAL ITERATIONS PERFORMED TO TEST THE

METHODOLOGY 108

APPENDIX D.1 INPUT AND OUTPUT FILES OF THE INSULATED ONE ZONE BUILDING . 113

APPENDIX D.2 CALCULATING BLAST HEAT PUMP PERFORMANCE COEFFICIENTS 128

APPENDIX D.3 COMPARING BLAST AND GLHEPRO WATER LOOP AND HEAT PUMP MODELS

130

APPENDIX E.1 COPY OF ONE OF THE DAYCARE CENTER BLUE PRINTS 133

APPENDIX E.2 BLAST INPUT FILE OF THE DAYCARE CENTER 135

APPENDIX E.3 TABLES OF THE DAYCARE CENTER LOADS ON THE HEAT PUMPS . 146

APPENDIX E.4 PSYCHROMETRIC CHARTS USED IN THE SELECTION OF THE DAYCARE

CENTER HEAT PUMPS . 156

APPENDIX E.5 BLAST OUTPUT FILE OF THE DAYCARE CENTER USING THE ORIGINAL CODE

161

APPENDIX E.6 GLHEPRO INPUT FILE FOR THE DAYCARE CENTER 180

APPENDIX E.7 BLAST AND GLHEPRO OUTPUT FILES FOR THE DAYCARE CENTER FOR A

TEN YEAR SIMULATION USING THE MODIFIED CODE 183