Lochinvar launches Optimus Gas Absorption Heat Pump

Boiler and water heater manufacturer Lochinvar has launched the Optimus range of Gas Absorption Heat Pumps (GAHPs) capable of delivering space heating and hot water to commercial buildings at extremely high efficiencies.

Heat pumps are becoming an increasingly popular solution for building operators intent on lowering their carbon footprint while improving heating and hot water performance. Gas absorption technology is another step forward in efficiency when compared with more traditional electrically driven equivalents.

Optimus delivers outputs of up to 41.7kW and is capable of operating with ambient temperatures as low as -20°C. It can achieve efficiencies as high as 152% by capturing low grade energy from surrounding air to supplement thermal output from the refrigeration cycle, which is driven either by a natural gas or propane burner.

Low temperature hot water can be supplied at up to 65°C for heating applications and up to 70°C for domestic hot water.

Outdoor installation provides a convenient space saving solution, but an indoor option is also available. The indoor model requires only a one square metre louvred opening in the plant room to allow for air intake.


The Optimus can be used in place of traditional gas-fired boilers to provide LTHW heating or hot water. It can also work in partnership with condensing gas-fired boilers with the integral controls giving priority to the Optimus unit so the boilers will only fire up during periods of higher heating demand. This guarantees both extremely efficient operation and extended equipment life. A similar principle applies for hot water applications where Optimus can provide pre-heated feed water for condensing water heaters.

Factory-assembled skid mounted packages, are also available in configurations from two to five Optimus GAHP units. These come pre-piped, pre-wired, and complete with external sensors and cascade control to reduce installation cost and time; and for ease of commissioning and maintenance.

The Optimus is designed to operate continuously, even in defrost mode, and uses a water/ammonia refrigerant solution with zero ozone depletion and global warming potential (GWP).  Traditional air-to-water electric heat pumps typically use fluorinated refrigerants (such as the HFCs R407C and R410A), which were developed to replace CFCs, but still have a significant GWP.

As a result, the GAHP approach will attract greater credits under the BREEAM (Building Research Establishment Environmental Assessment Methodology) building rating scheme.

Optimus will also be regarded very favourably under the European Eco-Design of Energy Related Products (ErP) Directive, which comes into force this September with the aim of improving the lifecycle performance of complete systems and energy consuming products.

“We are delighted to launch the GAHP product to market, in a year when there is an even stronger drive towards higher efficiencies from heating and hot water systems,” said Lochinvar managing director, David Pepper.

“The Optimus unit provides specifiers and contractors with an attractive solution for heating and hot water systems particularly when integrated with high efficiency gas-fired water heaters such as our Eco Charger Hybrid product range. Also for space heating applications, we envisage the Optimus being combined with either our floor standing or wall-hung condensing boilers to provide an efficient, cost-effective approach for many commercial applications.”