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CP3 Open-loop groundwater source heat pumps: Code of Practice for the UK (2019)
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CP3 Open-loop groundwater source heat pumps: Code of Practice for the UK (2019)

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Harnessing energy from water in the ground for heating and cooling


This Code of Practice has been produced as a joint project between the Chartered Institution of Building Services Engineers (CIBSE) and the Ground Source Heat Pump Association (GSHPA) with the backing of the Heat Pump Association (HPA). The work has been supported by the UK Department for Business, Energy and Industrial Strategy (BEIS).


Groundwater source heat pumps (GWSHPs) have huge potential and are an underused technology in the UK. Harnessing renewable energy from aquifers and mine water represents a huge opportunity to provide low carbon heating and/or cooling to buildings. However, if GWSHPs are to form a significant part of our future low carbon energy infrastructure they need to be designed, built, operated and maintained to a high quality to deliver customer satisfaction. This Code of Practice has been produced to help achieve these aims by raising standards right across the supply chain and to encourage adoption of the technology.


Setting minimum requirements (and recommending best practice) should provide greater confidence for specifiers and developers. This Code of Practice can also be included in the tendering/contracting process to specify minimum requirements for a project. The adoption of this Code of Practice by developers could ultimately be used to provide assurance to customers and property purchasers that their GWSHP scheme has followed a set of design, installation and commissioning standards. This Code of Practice should therefore have a significant effect on the GWSHP market by boosting confidence in the technology.


The Code of Practice can also be included in the tendering/contracting process to specify minimum requirements for a project. The adoption of this Code by developers could ultimately be used to provide assurance to customers and property purchasers that their GWSHP scheme has followed a set of design, installation and commissioning standards. It is anticipated that the Code should therefore have a significant effect on the GWSHP market by boosting confidence in the technology.


CIBSE, GSHPA and HPA are also working to develop training to ensure the skills necessary to implement the Code of Practice are available across the sector.


The draft of this Code of Practice was prepared by a consortium led by Themba Technology Ltd. under contract to CIBSE and in association with HPA and GSHPA.


Phil Jones (Chair of CP3 steering committee) says “The rapid decarbonisation of the electricity grid means that heat pumps are THE low carbon solution for providing heating and cooling in buildings. Ground water provides a relatively constant temperature source, making GWSHPs an efficient technology right across the year. This new Code of Practice sets out minimum standards to give the buildings sector confidence in applying GWSHPs correctly.”


Linked titles

CIBSE has so far published two other Codes of Practice in this area:

  • CP1: Heat Networks: Code of Practice for the UK (here) and supported by 'A Guide for Building Owners and Developers' (here)
  • CP2: Surface Water Source Heat Pumps: Code of Practice for the UK (here).

 

Contents:


Part A: How to use this Code


A1 Introduction

A1.1 Strategic purpose

A1.2 What is an open-loop groundwater source heat pump?

A1.3 Why install an open-loop groundwater source heat pump?


A2 Readership and scope of the Code of practice

A2.1 Readership

A2.2 Scope


A3 Structure of the Code of Practice

A3.1 Themes

A3.2 Responsibilities


Part B: Challenges and opportunities


B1 The heat pump

B1.1 Types of heat pump

B1.2 Heating and cooling

B1.3 Key design issues


B2 Groundwater sources and their characteristics

B2.1 Aquifers: the occurrence of groundwater in the subsurface

B2.2 Water wells and boreholes

B2.3 Groundwater from flooded mines and quarries


B3 Types of installation

B3.1 Open-loop doublet systems: abstraction with injection to aquifer

B3.2 Open-loop systems: abstraction only with discharge to surface water or sewer

B3.3 Standing column wells (SCWs): abstraction and injection to the same well or shaft

B3.4 Hybrid and mixed technologies


B4 Challenges and opportunities

B4.1 Heat networks (load side)

B4.2 Source side networks (SSN)

B4.3 Multivector and multivalent systems


B4.4 Retrofit installations 43

B4.5 Free cooling and heating 44

B4.6 Aquifer thermal energy storage (ATES) 48


Part C: The Requirements


C1 Stage 1: Preparation and briefing

C1.1 Objective 1.1: To commission the project in accordance with the Code of Practice

C1.2 Objective 1.2: To develop the specification/project brief


C2 Stage 2: Feasibility

C2.1 Objective 2.1: To identify and quantify the groundwater source

C2.2 Objective 2.2: To determine what permissions are necessary to access the groundwater

C2.3 Objective 2.3: To determine heat pump location and groundwater abstraction and discharge details, including cost estimates

C2.4 Objective 2.4: To accurately estimate peak and seasonal heating and cooling demands

C2.5 Objective 2.5: To agree suitable load-side operating flow rates, temperatures and control strategies

C2.6 Objective 2.6: To select the most appropriate heat pump system

C2.7 Objective 2.7: To assess operation and maintenance needs and costs

C2.8 Objective 2.8: To conduct a financial analysis to comprehensively evaluate the installation options

C2.9 Objective 2.9: To assess environmental impacts and benefits

C2.10 Objective 2.10: To analyse risks and carry out a sensitivity analysis


C3 Stage 3: Design

C3.1 Objective 3.1: To design for safety in construction, operation and maintenance

C3.2 Objective 3.2: To accurately determine peak heating and cooling demands and seasonal energy consumption profiles

C3.3 Objective 3.3: To accurately test and quantify the groundwater supply

C3.4 Objective 3.4: To design the groundwater abstraction and discharge details

C3.5 Objective 3.5: To apply for the permissions necessary to access the groundwater

C3.6 Objective 3.6: To specify the most appropriate heat pump system

C3.7 Objective 3.7: To design an efficient load-side hydraulic system interface

C3.8 Objective 3.8: To evaluate environmental impacts and benefits

C3.9 Objective 3.9: To design a data collection system to accurately record performance

C3.10 Objective 3.10: To update and refine the risk register and sensitivity analysis

C3.11 Objective 3.11: To confirm a cost statement for the main system elements of the project


C4 Stage 4: Construction and installation

C4.1 Objective 4.1: To reduce adverse environmental impacts of construction

C4.2 Objective 4.2: To reduce health and safety risks

C4.3 Objective 4.3: To install the groundwater abstraction and discharge system in accordance with the design

C4.4 Objective 4.4: To pressure test, flush clean, purge and fill all pipework and plant


C5 Stage 5: Commissioning

C5.1 Objective 5.1: To follow a structured commissioning management plan

C5.2 Objective 5.2: To commission the source side of the heat pump installation

C5.3 Objective 5.3: To commission the heat pump and immediate supply-side equipment

C5.4 Objective 5.4: To commission and calibrate the performance data collection system

C5.5 Objective 5.5: To carry out a formal handover and provide appropriate and comprehensive information to the operations team


C6 Stage 6: Operation and maintenance

C6.1 Objective 6.1: To reduce health and safety risks to staff, customers and the general public in operation and maintenance

C6.2 Objective 6.2: To minimise environmental impacts of operation and maintenance

C6.3 Objective 6.3: To deliver a maintenance schedule that maximises system efficiency, reliability and asset life

C6.4 Objective 6.4: To provide appropriate monitoring and reporting, including reliability and CO2 emissions


C7 Stage 7: Decommissioning

C7.1 Objective 7.1: To decommission the heat pump

C7.2 Objective 7.2: To decommission the source side


Appendices

Appendix A: Glossary of terms and acronyms

Appendix B: Key legislation

Appendix C: Useful contacts

Appendix D: Calculating system efficiency

Appendix E: Environmental best practice checklist

Appendix F: References and further reading


Index



Acknowledgements

Chair: Phil Jones, CP3 Steering Committee; Chair, CIBSE CHP and District Heating Group

John Findlay, Past Chair, Ground Source Heat Pump Association (GSHPA)


Authors:

The draft of this Code of Practice was prepared by a consortium led by Themba Technology Ltd. under contract to CIBSE and in association with HPA and GSHPA.


Lead authors: Nic Wincott, Jen Billings


Steering Committee: Project Team

Phil Jones (Building Energy Solutions) (Chair); David Matthews (Themba Technology Ltd.); Eileen Bell (CIBSE)


Steering Committee members

Corinna Abesser (British Geological Survey); Dave Banks (Holymoor Consultancy Ltd.); Mark Barson (Vaillant); Nick Boid (IFTech Ltd.); Anthony Coumidis (McBains Cooper); Chris Davidson (GeniusEnergyLab); James Dickinson (Buro Happold); John Findlay (Carbon Zero Consulting); Graham Hazell (Heat Pump Association); Roger Hitchin (BRE and CIBSE); Ross Lowrie (Environment Agency); Robert Mack (Glen Dimplex Heating and Ventilation); Tommy Moody (BEIS); Matthew Maskell (Glen Dimplex Heating and Ventilation); Colin Pearson (BSRIA); Mark Trevaskis (Lowara Xylem); Guus van Gelder (Groenholland UK Ltd.)


Other acknowledgements

Comments were received from corresponding members, including: Michael Crane (GI Energy); Geoff Ellison (Dragon Drilling); Sasha Krstanovic (Aecom); Martin Preene (Preene Groundwater Consulting)


Referees

Robin Curtis (GeoScience Ltd.); James Dickinson (Buro Happold); Roger Macklin (Hoare Lea LLP)


Consultation

This Code of Practice was made available for public consultation between 22 January and 21 February 2018.