THE KEY TO NON-DISRUPTIVE RETROFIT

Pete Seddon, Head of Technical at Rinnai, discusses how high-temperature heat pumps are a vital tool to help minimise disruption during retrofit projects.

Heat pumps are set to play a key role in the UK’s national decarbonisation journey, but can be problematic when being fitted in a domestic or commercial retrofit project, as a noticeable amount of disruption will occur during installation. Many changes to the heating system will have to be made including the radiators, pipework and electrical upgrades. The radiators may have to be replaced as heat pumps operate at a lower flow temperature than a traditional gas boiler (between 35°C and 55°C instead of between 60°C-75°C).

Pipework may also need to be altered since low temperature heat pumps require a a higher level of water flow rate than boilers to operate efficiently. While smaller pipes may prevent these water flow rates, larger pipes can transfer heat effectively and efficiently at lower temperatures.

Electrical upgrades will also be required if a normal temperature heat pump is installed. As the property’s main source of power transitions from fossil fuels to electricity, a service panel that is only designed to operate at 100-amps will not be sufficient, since heat pumps require high voltage circuits in cold weather.

HIGH-TEMPERATURE ALTERNATIVES

In contrast, high-temperature heat pumps (HTHPs) do not require any changes to be made to radiators or pipework when retrofitting. This is because HTHPs produce water that is heated to between 55°C and 80°C similar levels as a gas boiler. This means there is likely to be no need to rip out radiators or replace pipework. The design of a high temperature heat pump means that the installation will work with the existing infrastructure, not against it.

When compared to a standard heat pump in terms of installation, a HTHP is less problematic, quicker and therefore reduces internal dust and material waste and time taken when retrofitting. In fact, radiator and pipework compatibility means the HTHP can glide into operation once installed.

Rinnai’s R290 40kW and 50kW high temperature air source heat pumps are the largest of this product range and suitable for use with domestic hot water and heating projects. The R290 commercial air source heat pumps can be cascaded for greater heating and hot water output and are also a low global warming potential (GWP) heat pump that offers advanced controls. The R290 high-temperature heat pumps supply hot water up to 75°C, ensuring system and design flexibility. Rinnai’s range of heat pump technology comes with a smart control system that features demand side response functionality which further futureproofs sustainability.

All R290 models have low noise capability, making them suitable for areas with prohibitive sound legislation. The 40kW and 50kW air source heat pumps use R290 natural refrigerant gas which has a GWP of three, ensuring that the Rinnai R290 high-temperature heat pump range is a sustainable and a future proof heating and DHW solution. The 40kW and 50kW variants have a SCoP A+++ due to the increased efficiency achievable with the use of R290 refrigerant gas, meaning that the Rinnai range of high temperature heat pumps is one of the most cost-effective and economical heating solutions available. Rinnai recognises the importance of design support and system efficiency, and uses Seasonal Performance Factor (SPF), capital expenditure and operational expenditure to help specifiers choose the best solution.