Robur gas-fired absorption chillers & heat pumps
Robur SpA is an ISO9001 and ISO14001 certificated Italian manufacturer of solutions for heating, air conditioning and refrigeration that are able to significantly reduce the impact on the environment.
They produce a range of modular gas-fired air cooled chillers and heat pumps for commercial and industrial use. Being based on absorption cycle technology these systems are far more environmentally benign than their more conventional electrically driven equivalents.
There are more than 360,000 Robur chiller systems installed worldwide. Robur SpA has recently celebrated fifty years in business.
How they work
The concept of absorption cooling has been around since the late 18th century but has never reached the complete mainstream acceptance that its more conventional vapour compression brother has enjoyed. The origins of Robur’s highly efficient gas-fired chillers dates back to work carried out on domestic refrigerators for the Servel company in the USA by Albert Einstein.
A simple gas-fired absorption chiller contains 75% of the components that you would find in a conventional vapour compression chiller. It has a closed refrigerant circuit, it has an evaporator, it has an air cooled condenser and it has an expansion device. In fact the only difference is the way in which the refrigerant is moved around the circuit.
Instead of using an electrically driven compressor the absorption chiller uses a heat driven “compression process” based around a secondary cycle and an absorbent fluid (hence the name). The Robur chiller uses naturally occurring ammonia as the refrigerant and water as the absorbent.
Robur in the 21st Century
Following the successful application of absorption technology to domestic refrigeration in the 1950s and 60s, when over 4 million units were sold, the first commercial gas-fired chiller was produced by the Arkansas & Louisiana Gas Company (Arkla) in 1968.
Between 1968 and 1991, over 300,000 of these air cooled chillers were sold under a range of brand names with very little effort being made to modernise the product. We can only assume that the US manufacturers’ took to heart the old adage “if it ain’t broke don’t fix it”.
The modern era for gas-fired chillers began in earnest in 1991, when the highly respected Italian manufacturer Robur acquired the gas-fired chiller business of US manufacturer Electrolux.
After moving production to Europe, the process of product development and improvement began. From an efficiency and product range point of view, today’s gas-fired absorption chiller is now almost unrecognisable from its US produced predecessor.
For example, the gas utilisation efficiency of the Robur air cooled gas-fired modular chiller is now over 70%, which is a thirty four per cent improvement over it’s efficiency ten years ago.
However, the real technology leap, which has taken place over the past five years, has been the development of heat recovery and heat pump products. In applications where there is a heating demand as well as cooling – which is probably the majority of commercial building and process applications – gas-fired absorption heat pumps turn all efficiency, running cost and environmental arguments head over heels.
Typically, Robur gas-fired absorption heat pumps can produce hot water for heating at efficiencies of over 140%.