A guide to commercial heat pumps
Tim Mitchell from Klima-Therm explores the latest heat pump technologies and innovations that are driving performance and energy efficiency in commercial buildings.
For many decades, natural gas has fuelled the domestic heating industry, which is now facing a tricky transition to low carbon heat pumps. By contrast, the commercial sector has been at the forefront of heat pump adoption for many decades, albeit largely air-to-air, but nevertheless has had years of valuable experience fine-tuning the technology to suit various applications.
As the UK and Europe push towards Net Zero, the lessons learned in that time are shaping a new generation of commercial heat pumps that deliver year-round climate control and reduce operating costs, while meeting future decarbonisation and F Gas phase-down standards.
Polyvalent and four-pipe heat pumps
A polyvalent or multifunction four-pipe heat pump system comprises a pair of flow and return pipes for heating, and separate flow and return pipes for cooling. Not all four-pipe systems are polyvalent (for example, an air-cooled chiller with heat recovery would have four pipes but is not polyvalent in the sense that both sides of the system are not controllable), but those using truly polyvalent units maximise energy recovery and performance.
Polyvalent heat pumps combine multiple energy-managing functions into a single, compact unit. For example, they can deliver concurrent heating and cooling for different zones or supply domestic hot water while maintaining indoor comfort. They can recover heat from cooling processes, and vice versa, delivering excellent energy efficiency and reduced operating costs.
The ability to provide heating and cooling loads independently or simultaneously (not just seasonally, like reversible heat (pumps) makes polyvalent units a promising technological solution, especially in high-load buildings such as hospitals, hotels, universities and data centres, while improving energy efficiency and reducing reliance on auxiliary systems.
Reversible heat pumps
For buildings without constant dual heating and cooling demands, reversible heat pumps deliver adaptable, year-round comfort from a single system that either reverses the refrigerant flow around the heat exchange circuit in air-source machines or diverts the water to opposite sides of the vapour compression cycle in water-source machines.
With the ability to switch seamlessly between heating and cooling, they provide year-round comfort from a single integrated system, reducing capital expenditure, simplifying maintenance and, crucially, lowering operational emissions.
Advances in variable-speed compressors, electronic expansion valves and improved heat exchangers allow reversible systems to maintain stable supply temperatures even in extreme conditions, reducing plant complexity and energy consumption.
High-temperature heat pumps
One of the historic barriers to heat pump adoption in commercial retrofit has been the legacy requirement for high water temperatures. Many older systems depend on radiators or domestic hot water (DHW) circuits designed around 70–80°C supply. Replacing the heat-emitting or hot water storage equipment can be costly and disruptive, but the latest generation of high-temperature heat pumps can now deliver hot water reliably up to 75°C or even 80°C, making them highly compatible with legacy heating infrastructure.
High-temperature systems allow phased refurbishment, giving organisations the ability to decarbonise early without triggering a complete system redesign. They also address the critical hygiene requirements of healthcare, hospitality and sports facilities, ensuring DHW supplies meet legionella control strategies without relying on fossil-fuel boilers.
Natural refrigerants
F Gas phase-down schedules in the UK and EU are accelerating the need for HVAC replacement, with supply issues pushing up the cost of some legacy refrigerants.
The latest commercial heat pumps increasingly use natural refrigerants such as propane (R290) and CO2 (R744). These gases offer very low global warming potential (GWP) and excellent thermodynamic performance.
R290, in particular, has become popular in air-to-water heat pumps, achieving high efficiencies even at elevated temperatures. CO2 systems are proving well suited for DHW-intensive buildings due to their ability to produce very high outlet temperatures at efficiencies well above those of traditional refrigerants.
Smart system management
Most commercial buildings contain a complex web of HVAC systems, including chillers, heat pumps, boilers, split systems and more. Performance gains can be achieved by integrating these services under a multi-technology HVAC management system which intelligently sequences these assets in real time based on weather conditions, tariffs, available renewable power and building occupancy.
Advanced flow control technologies further enhance system efficiency. Variable primary flow (VPF) systems allow units to operate at flexible flow rates rather than constant
flow, leading to reduced pump energy consumption, improved reliability and simplified system control. Annual savings using VPF systems can be substantial, with some installations achieving energy reductions of up to 86% compared to traditional constant primary and secondary flow configurations.
Ask the expert
Specifying the right combination of HVAC systems – whether upgrading existing infrastructure or undertaking full replacement – requires careful consideration. The trade-off between the running and maintenance costs of older systems and the capital expenditure of new installations is rarely straightforward.
Success depends on understanding not just the technology, but how different solutions interact. Consulting an experienced HVAC specialist early in the design process is essential. The right partner brings not only technical knowledge of available systems, but practical insight into how they each perform across different applications – ensuring that specification decisions deliver both immediate performance and long-term value.
