Why should you consider using heat pumps in cascade for your next heat pump project?

As the global push towards net-zero emissions by 2050 intensifies, the demand for efficient, low-carbon heating solutions in commercial buildings is on the rise. Heat pumps are becoming a popular and reliable option for efficient heating, however, larger commercial properties with substantial heating and hot water needs often find a single heat pump unit insufficient. For these high-demand scenarios, a cascade heat pump system may be the ideal solution, offering enhanced efficiency and performance at reduced costs.

Heat pump cascade systems, like their modular boiler counterparts , integrate multiple heat pumps, which can operate independently or together, dividing out capacity, to meet specific heat demands. These systems are designed to adjust their output dynamically - when the demand is high, all units can work together to deliver a large, combined output, while during periods with reduced demand, they can function individually or at reduced capacities. This flexibility enhances energy efficiency by avoiding unnecessary consumption.

Why might you choose a cascade system? 

Cascade systems are ideal for properties with large or fluctuating heating and hot water demands, such as commercial buildings, whose demands may not be able to be met by a singular heat pump unit or hybrid system.

 

 

  • One of the main advantages of cascade systems is their ability to significantly improve the efficiency of heating output in commercial properties.  Cascade systems improve the Coefficient of Performance (COP) – the ratio of heat output from the condenser to the power supplied to the compressor – by offering high turndown ratios. This means they can operate efficiently at low outputs of their maximum capacity, providing more precise load matching with minimal wastage compared to a single unit. Rather than a single heat pump running inefficiently at partial load, the cascade setup allows multiple units to adjust their capacities as needed, ensuring a more accurate match to the actual heating demand and optimising overall performance.

 

 

  • When heat pumps are used in cascade, the system can adjust each unit’s output to keep them all within their most efficient operating conditions, improving the COP. This specialisation allows each heat pump to operate within its optimal performance range more frequently, resulting in an overall more efficient heating system. In turn, reducing running costs as the system requires less power to maintain the desired temperatures and making cascade systems a cost-effective solution for commercial properties.  

 

 

  • Another significant advantage of a cascade systems is their high modulation rate. Modulation rate refers to a heat pump's ability to adjust its output. In a cascade configuration, multiple units can work together or independently to meet specific heating requirements, providing better control over the system’s output. This means that during low-demand periods, only a few heat pumps may be working at low capacities while during peak demand, the units can perform at higher outputs or additional units will run, reducing inefficiency compared with operating a single, oversized heat pump at low capacity.

 

 

  • Cascade systems are particularly beneficial in scenarios where a property's power supply is insufficient to operate a large singular heat pump or hybrid system at full capacity. For example, in smaller commercial buildings with single-phase supply, a cascade system might be the ideal solution to optimise performance. A cascade system can balance the load across multiple heat pumps, reducing the total required supply, whilst still delivering your heating requirements.

 

 

  • Cascade systems could potentially save space in commercial properties. By using several smaller heat pump units instead of one large unit, the smaller heat pumps can fit into tighter spaces. This is particularly beneficial when a large heat pump necessary to meet the building’s heat demand would require significant alterations to the building's structure.

 

 

  • Cascade heat pump systems can increase reliability. Unlike single heat pump systems, where a failure can lead to complete system downtime, a cascade setup uses multiple units. If one heat pump fails, the remaining units can continue to operate at increased capacity, ensuring uninterrupted heating. Cascades not only reduce the risk of a total system failure but also spread the workload across multiple units, reducing strain and wear on individual components. Additionally, the independent units that make up the cascade systems allow for independent maintenance, further improving operational reliability. By optimising load sharing, cascade systems can improve long-term reliability and reduce potential maintenance challenges.

Navigate the selection process with Hamworthy Heating

Hamworthy Heating works with commercial consultants and specifiers to help them find the right solution for their energy-efficient and low carbon heating solutions for their commercial projects. Whether that’s support with technical information, or with the latest low-carbon heating and hot water technology for a cascade setup, the Hamworthy Heating specification team can help you find the right product for your project’s needs.  

  • For more information on how a cascade system might be suitable for your project, get in touch with your Area Sales Manager.
  • Want to learn more?  Join us for our upcoming CPD on ‘Air Source Heat Pump Selection, Specification and Design’, or explore Hamworthy Heating’s full range of CPDs here!
  • Considering funding for your low carbon heating project? Have a look at our ASK Hamworthy article on what funding is available in commercial buildings.