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HEAT PUMP GUIDE Avoiding ‘eco-bling’


Electrifying heat where possible should be the aim, but not at the expense of solid design practice, says Ryan Kirkwood, heat pump business development manager at Baxi


A


s organisations brace themselves for astronomical surges in energy prices, just as the heating season begins, continuing to make


progress towards decarbonisation will be a tough challenge for many. Ultimately, the aim is to transition to low carbon heating technology such as heat pumps. Reflecting this, government funding is mostly limited to full electrification of heat – helping scale up the heat pump market and meet its ambitious target of 600,000 units a year by 2028.


Complex challenges


But spending the entire budget on a heat pump to decarbonise an older, draughty non-domestic building without any other preparation will not necessarily guarantee success. The problem is that in existing buildings, the


transition to fully electric low carbon heating and hot water provision is far more complex than in new and well-insulated building stock. On every refurbishment project, there will be a number of constraints, including time, budget, available power and physical space. As a result, these buildings will likely need a series of adaptations, typically carried out in phases, to make them heat-pump ready. It all comes down to ensuring solid design practice.


At the end of the day, what no one wants is a poorly performing heat pump that will result in high running costs, an inadequately heated building, and unreliable heating and hot water.


Best practice design


Back in 2010, Doug King, Visiting Professor of Building Engineering at the University of Bath, coined the term ‘eco-bling’ to describe “unnecessary renewable energy visibly attached to the outside of poorly designed buildings.”


King’s point was that simply adding renewable technologies to a building that is poorly designed and energy hungry is unlikely to deliver the intended environmental benefit. He recommended taking time to understand how and where the building uses energy and then designing ways to improve its efficiency.


Left: Ryan Kirk- wood, heat pump business develop- ment manager at Bax


Right: Remeha E-HP AW Air Source Heat Pumps


This same best practice design must be applied to heat pumps if we are to ensure optimal performance and avoid ‘eco-bling’.


Decarbonisation roadmap


Working together, manufacturers and heat experts can provide valuable support to organisations looking to reduce the carbon intensity of their buildings. A good starting point is to encourage them to plot an achievable pathway to net zero. Understanding the time available to complete the work, the budget and any funding opportunities will make it easier to plan a phased approach that will enable them to achieve their goals. Energy efficiency must be prioritised in older buildings. By budgeting first for energy efficiency measures such as insulation, draught proofing and double glazing, energy losses and energy usage can be reduced. Developing an energy consumption profile of the building is also advisable, as recommended by King. Data can be gathered through analysis of energy bills or meter readings, as well as measuring real flow rates in different places and conditions, over a given time.


The energy usage patterns will reveal the peaks in heating and domestic hot water demand and how it compares to the current plant and heat emitter sizing. Armed with this data and an awareness of the


project constraints, we can then understand where heat pumps can be most effectively used and design accordingly. For example, if the energy data reveals that air handling units (AHU) are accounting for a sizeable proportion of the heating load, one option might be to


bracket the space heating system. Modular AHUs are generally served by a separate CT circuit and have coils that are relatively easy to swap from high to low temperature (access problems aside). Using heat pumps to help decarbonise a considerable part of the heating demand would be a valuable step towards improved sustainability. Alternatively, in a building with high domestic hot


water (DHW) demand and low heating demand, and a marginal amount of spare electrical capacity, a small ASHP may be enough to provide a sizable amount of preheat to the DHW demand utilising proper thermal storage. Where an all-electric approach is not feasible,


multivalent methods of heat and hot water generation should not be overlooked as an early stage of the heat decarbonisation process. Utilising existing or new high efficiency combustion fuelled appliances with heat pumps is time proven to decarbonise a large portion of the annual heat demand. The heating sector will be instrumental in providing


guidance and support to organisations tackling the decarbonisation challenge. Working together, we can help them to balance best performance for budget value with best practice for heat decarbonisation – and in so doing, avoid ‘eco-bling’.


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