A step towards renewable energy

Darran Smith, technical manager at Alpha, looks at why a hybrid solution provides a better option for some homeowners than a full heat pump installation, and answers some of the questions that heating engineers frequently ask.

The domestic heating sector is set to go through a revolution over the coming years. Homeowners will undoubtedly be looking to heating engineers to help them decide how to move towards renewable energy. There are a host of electric heat pumps coming to the market but many homes may not meet the requirements to take on a heat pump-only offering.

One option is a hybrid approach, where a heat pump is installed to provide the majority of the space heating, with a boiler back-up to provide hot water. When combined with smart tech controls, you have high-efficiency heating and hot water that provides a perfect pathway into renewable heating.

Why a hybrid?

You’ll need to work with the homeowner to discover the best solution for them. Many homes may not be ready for a full heat pump. This could be down to a number of factors:

• Poor insulation

• The need to replace older radiators with new, bigger and more effective models

• The property may be older, with solid walls and no cavity insulation

• The property may be listed and therefore harder to modify

• Not having a suitable location for a full heat pump solution

• Cost.

A hybrid could be the answer. Because the system can run off the existing pipework, your customer doesn’t need to worry about drastic changes to their heating system, such as upgrading radiators and pipework. The system cleverly combines live energy prices with the outdoor temperature to choose the most efficient combination to heat the home. And, when hot water is needed,

Alpha’s most recent hybrid heat pump course provides training in packaged heat pump solutions. The one-day hybrid course is free and includes: key features of the Alpha hybrid solution, considerations when fitting a heat pump, system design, positioning and installation.

Hybrid installer checklist

✔ Is the property suitable? You’ll need to discover if the home has sufficient space and the correct clearance, as well as whether it falls within permitted development or needs planning permission

✔ Is there sufficient power supply? We recommend that the heat pump is wired to the consumer board, with its own breaker (16amp). Do you have the correct cables and has a Part P registered electrician attended before installation?

✔ Are you ready for installation? Make sure you’ve got the correct pipe lagging and choose to use either an antifreeze valve or add glycol to the system it is provided instantly by the gas boiler.

A full heat pump system can be costly, but a hybrid approach provides a transitional step to renewable energy at a lower cost. Over time, customers can upgrade their radiators, use the heat pump more and watch the efficiency change as the house adjusts to a low-temperature system.

FAQs

Q. Does the system work on microbore?

Yes, we have installed systems on microbore and have not received any negative effects. However, increasing pipe diameters will help to increase efficiency. The system must be clean with good circulation for this to be successful.

Q. Does the hybrid need a buffer tank?

Not necessarily. We ask for 20 litres of ‘open volume’ to allow the system’s anti-freeze protection to function. Open volume can be unrestricted radiators or open flow-and-return pipework: think radiators without TRVs fitted.

Q. How much power does the heat pump draw?

The maximum absorbed current is 2.3kW, but in general running it averages around 1,500 watts, depending on demand – similar to plugging in a hairdryer.

✔ Is the system commissioned properly? To achieve high efficiency, the system must be hydraulically balanced and correctly wired with the necessary account created for the smart controls (completed with accurate energy tariffs uploaded).

Q. Do I need to add glycol to the system?

You can: however, an anti-freeze valve is included that you can fit inside the heat pump’s casing. Fitting this eliminates the need for glycol. n