Opinion

Hidden dangers

Bob Long, MD Eco Innovate Ltd
Bob Long, MD Eco Innovate Ltd

With the domestic RHI so close to finally becoming reality, there is a grave danger that insufficient levels of skills in the industry could expose a weak link, says heat pump specialist Bob Long

So significant is this pending issue that we here at Eco-Innovate Ltd have dedicated over two years of research, design, development and prototyping, to develop a small number of system components, that effectively de-skill much of the design process – thereby simplifying installations to guarantee reliability, economy and customer satisfaction.

The RHI represents a much needed boost to the heat pump industry, but the practicalities of finding enough skilled labour to deliver the anticipated volume of sales is a little more daunting.

Currently (pre-RHI), many of the heat pump installations installed in UK are owned by enthusiasts who have embraced low-carbon technology and have a particularly good understanding of their chosen system.

It is not uncommon for green enthusiasts to mix multiple technologies such as heat pumps, solar thermal, PV and perhaps even a Log burner too!

In an ideal world, where cost of implementation is not an issue, the low carbon impact of multiple-technology systems is commendable. But to the majority of new customers enticed by the RHI, a heat pump will represent nothing more than an economical heating alternative for the home.

In the anticipated wave of new customers, there will be no room for error and excessive heating bills for whatever reason will not be tolerated.

Most households in UK will currently have only one type of heating technology such as a gas or oil boiler and understandably, will have little interest in the technicalities of the heating system.

With this in mind, it is reasonable to assume that the majority of domestic heat pumps installed under the RHI will operate as a single heat source, negating any need for the heat pump to interface with other technologies.

If this assumption proves to be correct, much of the complexity, built in to many high-end heat pumps, could be eliminated, and would simplify an installation significantly.

Although there is sound argument in support of increased efficiency through sophisticated control, there is absolutely no merit in economic losses through poor adjustment.

Some heat pump manufacturers have incorporated control electronics with such a high level of sophistication that in-house training is essential before allowing installers to make a purchase.

Even with all this emphasis on training, there remain an insufficient number of skilled installers for the anticipated uptake of heat pump technology.

When designing a heat pump system, the basic considerations are very similar to a conventional fossil fuelled system:-

a.)    Correct size of boiler, sized to match the highest anticipated heat load

b.)    Adequate water flow rate

c.)     Suitable size of emitter

d.)    Domestic hot water requirement based upon number of occupants/bathrooms

There is however one major difference: A fossil fuelled heating system can be oversized without much increase to installation or running cost, ensuring there is more than enough capacity for any eventuality.

Beyond this, fossil fuelled systems are relatively tolerant to operating at higher temperatures, and systems can be tuned to meet requirements by simply adjusting the working-fluid temperature, and duty cycle.

A heat pump powered system cannot provide this flexibility, which means that much higher accuracy is required in the initial design stage, and precisely selected components such as water pump(s) and heat-emitters are essential to success.

In the passage of time, familiarity with heat-pump technology will grow, and installation procedures will evolve into a straightforward, manageable process. However, at in this embryonic stage, the greatest care must be exercised with every installation, and the value of simplicity must never be understated.