Gas absorption: The alternative heat pump technology

Pure Thermal has relaunched Gas Absorption Heat Pumps (GAHP) in the UK, providing a practical transitional solution on the path to net zero.

 

Pure Thermal recently relaunched the Italian manufactured Robur Commercial Gas Absorption Heat Pump range back into the UK market as the appointed UK partner. Commercial Gas Absorption Heat Pumps (GAHP) were widely applied throughout the UK from Robur up until 2014 with hundreds of units successfully operating nationally.

However, during the period where the electrification of heat and fuel switching from gas became the industry priority Robur Gas Heat Pumps left the UK due to the increasing focus on electrically powered heat pumps and direct electric forms of heating.

But as we get nearer to 2050 a realisation has occurred, this being that it is now clear that a need for more transitional measures to accelerate carbon reduction has become apparent.

However, during the period where the electrification of heat and fuel switching from gas became the industry priority Robur Gas Heat Pumps left the UK due to the increasing focus on electrically powered heat pumps and direct electric forms of heating. But as we get nearer to 2050 a realisation has occurred, this being that it is now clear that a need for more transitional measures to accelerate carbon reduction has become apparent.

These savings are achieved via Heat Pump technology, but without the need for increased electrical supplies.

Consider that upgrading electrical supplies for retrofit commercial heat pump applications is costly and can be difficult to obtain due to regional or local electricity supply issues. Garry Broadbent, Operations Director, at Pure Thermal commented: “We have 25 years until 2050 and it’s clear that a more transitional approach, rather than immediate fuel switching from gas, can really benefit some carbon reduction focused applications”, continuing, “We would ask if GAHP technology has been overlooked, in favour of electric heat pumps, because gas is seen as something that must be removed rather than gas usage being reduced”.

However, it’s clear that the situation can be viewed differently where GAHP are able to provide a transitional heat pump opportunity with electrification to follow.

This means that lower capital cost carbon reduction measures can be applied immediately via GAHP and long delays/ costs for new electrical supplies can be avoided.

 

So, what are the benefits of GAHP and why should they be considered?

Garry states: “GAHP are relatively straightforward to apply as they use the incumbent/existing gas supply and use only 1 kW electricity to generate 40kW of heat”, continuing, “consider that we have a commercial gas heater which is more than 100% efficient offering an immediate reduction in gas usage when compared to boilers”.

Taking the mantra of using less gas rather no gas, the application of GAHP can make real sense for applications that do not have cost effective or timely access to increase electrical supplies in order to install electrically powered heat pumps.

Considering the Robur GAHP track record, the question of proven technology is answered by there being hundreds of GAHP operating in the UK having been widely applied since 2004.

A modular approach is taken to GAHP specification utilising the Robur A-Plus 40kW unit in single or parallel unit configuration. There is also the option to specify factory assembled skids with multiple GAHP units mounted in a single system plus there is also the additional option to select a hybrid system with heat pumps and skid mounted externally located boilers.

This option provides a complete hybrid solution by sizing the Gas Heat Pumps to cover the maximum amount of carbon reductions and only bringing the Gas Boiler into play below an external temperature of say 5°C in order to provide additional capacity support.

With respect to current UK demands, the application team at Pure Thermal are confident that the configuration options and case studies within both the UK and throughout Europe will be able to demonstrate correct GAHP application methods to provide confidence to specifiers and designers.

It must be considered that this is not new technology, on the contrary this is extremely well-established technology with successful application going back over the last 20 years with GAHP simply being a different type of heat pump refrigeration system to the vapour compression refrigeration system found in an electric heat pump.

 

How do they GAHP work?

GAHP units utilise a burner to place heat into the refrigeration circuit unlike the electrical compressor which does the same job in a vapour compression system, however, both types utilise air source or ground/water source renewable energy.

In summary GAHP units use gas to generate heat using renewable source energy, be it air or water, to provide a system that will use circa 40% less gas than the incumbent boiler. Hence, we have a heat pump system which is practical and easy to apply & integrate with existing gas supplies with an output temperature capability of 70°C.

 

Training and support

Garry said: “Product & application training is an important element of the Pure Thermal package and for GAHP we provide full training for designers and specifiers and contractors that are new to the concept of GAHP”.

Several webinars and training sessions are planned throughout Q1 and Q2 by Pure Thermal that will demonstrate that GAHP are simply just another type of heat pump powered by gas rather than electricity.

 

Conclusion

The present unknown situation regarding the use of the gas in the future is still to be determined with a consultation concerning the Gas Transition launched in November 2025. However, when considering the use of gas, it is noted that in Q4 of 2025 a significant investment of circa £150 million was placed by Government into making ready certain sections of the grid to take advantage of hydrogen to a mix of 5%.

Alongside this it should also be noted that Biogas is gaining more momentum as is also the case in Spain and Italy with the objective of supplying the grid with clean renewable gas.

In summary this indicates that the application of GAHP can be viewed as an immediate transitional carbon reducing technology for the next 15 years until remedial improvements to the Electricity Grid ensure that power is more readily available to apply electric heat pumps.

Or importantly it can be considered that GAHP may be a technology that could be viewed as long term to operate for many years with a gas grid circulating clean gas that could be a mix with a Biomethane or Hydrogen base.

But whichever view is taken, whether transition or long term, there is no doubt that GAHP technology is proven and ready to be applied now for both new or retrofit applications.