The UK has set a legally binding target to achieve net zero greenhouse gas emissions by 2050. Achieving this will require virtually all heat in buildings to be decarbonised, and heat in industry to be reduced to close to zero carbon emissions.
CIBSE AM17: Heat pumps for large non-domestic buildings provides and consolidates best practice guidance with the aim of supporting high quality design, installation, commissioning, operation and maintenance of large heat pump systems.
This document is principally aimed at building services designers, and therefore assumes a base level of technical understanding around building services systems. This guide will also be of use to other readers including developers, installers and operators who are involved in the application of heat pumps to large non-domestic buildings. A key aim of this document is to increase awareness of the common issues faced in delivering effective heat pump systems in larger buildings, thereby reducing future instances of ineffective systems.
For the purposes of this guide, large heat pump installations have been defined as those with a thermal output of over 45 kW. The guide covers heat pumps which provide space heating, cooling, domestic hot water (DHW), and process heat.
The guidance assumes that a heat pump has already been selected as the preferred primary heat source and principally covers installations within the UK market.
AM17 provides guidance on both new-build applications and the retrofit of heat pumps to existing buildings.
Note: A corrigendum to AM17 was issued on 24th July 2023 and updated on 28th May 2024, making changes to the formulae depicted in Figure 32 on page 43 and the wording of the final row of Figure 30 on page 40. Please download the corrected version of the PDF, above. If you purchased the hard copy, you can download a copy of the corrigendum here.
1. Introduction
1.1. Scope and purpose of this guidance
1.2. Measures of success
1.3. Policy context
2. Building requirements
2.1. Reduce demand
2.2. Establish system requirements
2.3. Summary of heating and cooling demand characteristics
3. Heat pump technology
3.1. Types of heat pump
3.2. Carbon dioxide heat pumps
3.3. Modes of operation
3.4. Operating envelope of a heat pump
3.5. Efficiency
3.6. Part load performance
3.7. Defrost cycles
4. Sizing
4.1. Level of centralisation
4.2. System schematic
4.3. Bivalent system sizing
4.4. Sizing for different modes of operation
4.5. Cascaded systems
4.6. Sizing for defrost
4.7. Buffers and thermal storage
4.8. Resilience
5. Impact on architecture and building design
5.1. Plant space allocation and services distribution
5.2. Plant replacement strategy
5.3. Acoustics
5.4. Interconnection of buildings
6. System performance optimisation
6.1. Modelling for optimum performance
6.2. Stakeholders
6.3. Controls
6.4. Distribution temperatures
6.5. Electrical infrastructure
6.6. Heat sharing
6.7. Hydraulic design
6.8. Hydraulic breaks
6.9. Pipework insulation
6.10.Parasitic losses
7. Costs
7.1. Capital
7.2. Operational costs
7.3. Commissioning
7.4. Initial commissioning
8. Seasonal commissioning
8.1. Metering and monitoring
9. Installation stage requirements and workmanship
9.1. Minimum installer skills
9.2. General workmanship requirements
9.3. Ground source heat pumps
10. Operation, aftercare, and user guidance
10.1.User guides and handover
10.2.Maintenance
11. Whole life carbon and decommissioning
11.1. System lifespan
11.2.Whole-of-life carbon and the circular economy
Annex A: Glossary of terms and abbreviations
Annex B: Decoding a heat pump datasheet
Authors: Joshua Bird, Ilaria Ricci Curbastro, Michael Edwards, Iona Norton, and Alec Tyson (Arup)