An Introduction to Thermogeology Ground Source Heating and Cooling

by Banks, David

• ISBN13: 9780470670347
• ISBN10: 0470670347
• Edition: 2nd
• Format: Hardcover
• Copyright: 2012-08-13
• Publisher: Wiley

Summary

This authoritative guide provides a basis for understanding the emerging technology of ground source heat pumps. It equips engineers, architects, planners, regulators and geologists with the fundamental skills needed to manipulate the ground's huge capacity to store, supply and receive heat, and to implement technologies (such as heat pumps) to exploit that capacity for space heating and cooling. The author has geared the book towards understanding ground source heating and cooling from the ground side (the geological aspects), rather than solely the building aspects. He explains the science behind thermogeology and offers practical guidance on different design options. The book is aimed primarily at professionals whose skills areas impinge on the emerging technology of ground source heating and cooling. They are aware of the importance of the technology and wish to rapidly acquire fundamental theoretical understanding and design skills.

Author Biography

David Banks is one of the Britain's leading hydrogeologists and has been instrumental in promoting ground source heating and cooling within the UK. He has over 26 years international experience from consultancy, the public sector, academia and commercial training. He runs his own business, Holymoor Consultancy Ltd, and has taught at the Universities of Sheffield, Leeds and Newcastle-upon-Tyne. Most recently, he has been a trainer on the EU's Geotrainet programme.

Table of Contents

About the Author	p. xi
Preface to the First Edition	p. xiii
Preface to the Second Edition	p. xv
Acknowledgements	p. xvii
An Introduction	p. 1
Who should read this book?	p. 2
What will this book do and not do?	p. 2
Why should you read this book?	p. 3
Thermogeology and hydrogeology	p. 6
Geothermal Energy	p. 11
Geothermal energy and ground source heat	p. 11
Lord Kelvin's conducting, cooling earth	p. 12
Geothermal gradient, heat flux and the structure of the earth	p. 14
Internal heat generation in the crust	p. 16
The converting earth?	p. 17
Geothermal anomalies	p. 19
Types of geothermal system	p. 27
Use of geothermal energy to produce electricity by steam turbines	p. 28
Binary systems	p. 28
Direct use	p. 30
Cascading use	p. 30
Hot dry rock systems [a.k.a. 'enhanced geothermal systems (EGS)']	p. 32
The 'sustainability' of geothermal energy and its environmental impact	p. 35
And if we do not live in Iceland?	p. 38
The Subsurface as a Heat Storage Reservoir	p. 40
Specific heat capacity: the ability to store heat	p. 41
Movement of heat	p. 45
The temperature of the ground	p. 51
Insolation and atmospheric radiation	p. 55
Cyclical temperature signals in the ground	p. 59
Geothermal gradient	p. 61
Human sources of heat in the ground	p. 65
Geochemical energy	p. 69
The heat energy budget of our subsurface reservoir	p. 70
Cyclical storage of heat	p. 72
Manipulating the ground heat reservoir	p. 74
What Is a Heat Pump?	p. 79
Engines	p. 81
Pumps	p. 84
Heat pumps	p. 85
The rude mechanics of the heat pump	p. 88
Absorption heat pumps	p. 91
Heat pumps for space heating	p. 91
The efficiency of heat pumps	p. 93
Air-sourced heat pumps	p. 96
Ground source heat pumps	p. 98
Seasonal performance factor (SPF)	p. 99
GSHPs for cooling	p. 100
Other environmental sources of heat	p. 100
The benefits of GSHPs	p. 101
Capital cost	p. 104
Other practical considerations	p. 107
The challenge of delivering efficient GSHP systems	p. 108
Challenges: the future	p. 109
Summary	p. 112
Heat Pumps and Thermogeology: A Brief History and International Perspective	p. 114
Refrigeration before the heat pump	p. 115
The overseas ice trade	p. 117
Artificial refrigeration: who invented the heat pump?	p. 119
The history of the GSHP	p. 121
The global energy budget: how significant are GSHPs?	p. 129
Ground source heat: a competitor in energy markets?	p. 132
Ground Source Cooling	p. 133
Our cooling needs in space	p. 133
Scale effects and our cooling needs in time	p. 134
Traditional cooling	p. 135
Dry coolers	p. 136
Evaporation	p. 138
Chillers/heat pumps	p. 141
Absorption heat pumps	p. 143
Delivery of cooling in large buildings	p. 144
Dehumidification	p. 145
Passive cooling using the ground	p. 145
Active ground source cooling	p. 147
An example of open-loop groundwater cooling	p. 148
Options and Applications for Ground Source Heat Pumps	p. 150
How much heat do I need?	p. 150
Sizing a GSHP	p. 156
Open-loop ground source heat systems	p. 161
Closed-loop systems	p. 173
Domestic hot water by ground source heat pumps?	p. 191
Heating and cooling delivery in complex systems	p. 195
Heat from ice	p. 201
The Design of Groundwater-Based Open-Loop Systems	p. 202
Common design flaws of open-loop groundwater systems	p. 203
Aquifers, aquitards and fractures	p. 203
Transmissivity	p. 205
Confined and unconfined aquifers	p. 206
Abstraction well design in confined and unconfined aquifers	p. 208
Design yield, depth and drawdown	p. 210
Real wells and real aquifers	p. 215
Sources of information	p. 217
Multiple wells in a wellfield	p. 222
Hydraulic feedback in a well doublet	p. 227
Heat migration in the groundwater environment	p. 234
The importance of three-dimensionality	p. 240
Mathematical reversibility	p. 242
Sustainability: thermally balanced systems and seasonal reversal	p. 243
Groundwater modelling	p. 244
Examples of open-loop heating/cooling schemes	p. 245
Further reading	p. 246
Pipes, Pumps and the Hydraulics of Closed-Loop Systems	p. 248
Our overall objective	p. 251
Hydraulic resistance of the heat exchanger	p. 252
The hydraulic resistance of pipes	p. 253
Acceptable hydraulic losses	p. 255
Hydraulic resistances in series and parallel	p. 255
An example	p. 256
Selecting pumps	p. 262
Carrier fluids	p. 265
Manifolds	p. 271
Hydraulic testing of closed loops	p. 275
Equipping a ground loop	p. 277
Subsurface Heat Conduction and the Design of Borehole-Based Closed-Loop Systems	p. 279
Rules of thumb?	p. 279
Common design flaws	p. 282
Subsurface heat conduction	p. 283
Analogy between heat flow and groundwater flow	p. 286
Carslaw, Ingersoll, Zobel, Claesson and Eskilson's solutions	p. 289
Real closed-loop boreholes	p. 294
Application of theory - an example	p. 304
Multiple borehole arrays	p. 313
Simulating cooling loads	p. 321
Simulation time	p. 322
Stop press	p. 323
Horizontal Closed-Loop Systems	p. 325
Principles of operation and important parameters	p. 326
Depth of burial	p. 327
Loop materials and carrier fluids	p. 328
Ground conditions	p. 329
Areal constraints	p. 333
Geometry of installation	p. 333
Modelling horizontal ground exchange systems	p. 344
Earth tubes: air as a carrier fluid	p. 351
Pond- and Lake-Based Ground Source Heat Systems	p. 353
The physics of lakes	p. 354
Some rules of thumb	p. 356
The heat balance of a lake	p. 357
Open-loop lake systems	p. 365
Closed-loop surface water systems	p. 367
Closed-loop systems - environmental considerations	p. 371
Standing Column Wells	p. 372
'Standing column' systems	p. 372
The maths	p. 376
The cost of SCWs	p. 377
SCW systems in practice	p. 379
A brief case study: Grindon Camping Bam	p. 379
A final twist - the Jacob doublet well	p. 381
Thinking Big: Large-Scale Heat Storage and Transfer	p. 383
The thermal capacity of a building footprint	p. 384
Simulating closed-loop arrays with balanced loads	p. 385
A case study of a balanced scheme: car showroom, Bucharest	p. 390
Balancing loads	p. 392
Deliberate thermal energy storage - closed-loop borehole thermal energy storage (BTES)	p. 395
Aquifer thermal energy storage (ATES)	p. 398
UTES and heat pumps	p. 403
Regional transfer and storage of heat	p. 403
Thermal Response Testing	p. 410
Sources of thermogeological data	p. 410
Laboratory determination of thermal conductivity	p. 411
The thermal response test (TRT)	p. 412
The practicalities: the test rig	p. 417
Test procedure	p. 420
Sources of uncertainty	p. 425
Non-uniform geology	p. 426
Non-constant power input	p. 426
Groundwater flow	p. 427
Analogies with hydrogeology	p. 428
Thermal response testing for horizontal closed loops	p. 429
Environmental Impact, Regulation and Geohazards	p. 432
The regulatory framework	p. 432
Thermal risks	p. 437
Hydraulic risks	p. 444
Geotechnical risks	p. 449
Contamination risks	p. 451
Geochemical risks	p. 453
Microbiological risks	p. 454
Excavation and drilling risks	p. 455
Decommissioning of boreholes	p. 458
Promoting technology: subsidy	p. 459
The final word	p. 460
References	p. 463
Study Question Answers	p. 493
Symbols	p. 503
Glossary	p. 509
Units	p. 515
Index	p. 518
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