Proving heat pump viability with existing systems - Cooling Post

UK: Mitsubishi Electric has published a new white paper which it says proves the compatibility of heat pumps with microbore pipework.

The paper offers guidance for installers and homeowners looking to make the switch to heat pumps without replacing their entire heating systems.

Reusing microbore pipework, which is commonly found in new homes built in the 1970s and 80s, will reduce the retrofit cost of installing a heat pump.

The white paper, The Mitsubishi Electric Guide to Residential Air Source Heat Pumps and Microbore Pipework, claims that concerns about retrofitting costs and misinformation about heat pump technology have slowed progress towards the government’s target of installing 600,000 heat pumps annually.

“With up to five million UK homes fitted with microbore pipework, we’re pleased to demonstrate through our research that modern heat pumps can be effectively paired with these existing systems, saving on both installation costs and disruption,” commented Joanna Crown, Mitsubishi Electric’s product marketing manager.

Microbore pipework, characterised by pipes with a diameter of less than 15mm, became popular in the 1970s and 1980s due to its affordability and ease of installation. Traditionally, these systems were considered incompatible with heat pumps, which operate at lower temperatures and smaller ΔT. However, Mitsubishi Electric’s research shows that with the correct design and calculations, Ecodan heat pumps can be successfully retrofitted to homes with microbore pipework.

Key findings in the white paper include recommendations for installers, outlining how to match existing heating system operating conditions with the performance of the heat pump.

Mitsubishi Electric’s study is said to have shown that its Ecodan heat pumps can be integrated with existing microbore systems. This, it says, can be achieved by matching operating conditions of the heat pump with those of the existing heat distribution system (eg pipes and emitters such as radiators, underfloor heating and fan-coils), particularly in terms of flow temperature and ∆T.

However, it insists it is crucial to assess its suitability based on specific heating requirements. Factors such as flow rate, heat load, and compliance with CIBSE guidelines, including pressure drop and flow velocity limitations of 350 Pa/m and 1m/s, respectively, should be carefully considered to ensure optimal performance and efficiency.