The firms, whose products are focused on sustainability and biodiversity, entered the Gogarburn Innovation Challenge, which attracted 107 entries for innovations to help the bank reduce its environmental impact.

The bank's HQ to the west of Edinburgh became a symbol for bank excess during the 2008 credit crunch as it splurged £350 million on the building under the reign of former chief executive Fred Goodwin and became a focal point for anger over lavish spending and opulent furnishings.

RBS has since moved to reposition the building as a centre for innovation, supporting small businesses and startups in the local economy, by transforming its former executive wing into a startup accelerator for entrepreneurs.

John Hayes, head of workplace services at RBS, says of the latest initiative: “We have a range of targeted challenges at Gogarburn, including reducing energy, water and waste consumption and enhancing biodiversity. Through the Gogarburn Innovation Challenge we wanted to find innovative products and solutions which would help us meet these challenges. At the same time we wanted to help small businesses, who often find they aren’t able to properly test their new products in their intended environment. The Challenge provides that opportunity while allowing us to reap the benefits of their innovations.”

The winning entries include:

• Hydromx: An innovative nanofluid by Energy Effective Ltd, which replaces water in central heating and air conditioning systems to improve the efficiency of the system by between 20% - 35%.
• Waterblade: A flow modification device fitted to washroom taps, allows you to wash your hands effectively whilst halving the amount of water used.
• Honeybee colonies: From Kelvin Valley Honey, which will be installed to enhance biodiversity and enable the production of Gogarburn honey and beeswax products.
• air2eau: An atmospheric water generator which extracts moisture from the atmosphere and filters it into the purest drinking water available.
• Topolytics: A cloud based software platform that makes it easy for companies to organise, visualise and share information on their impact on the environment including waste, water emissions and resources.
• ‘Coolnomix’: A retrofit energy-saving device for air conditioning, by Peace Marsh Renewables Ltd, which produces savings of 25% - 35% of the unit’s electrical running costs by optimising the run-time of the cooling system compressor.
• eXpert Fridge: A refrigeration management and optimisation solution from Cotopaxi Ltd, which improves the reliability and energy consumption in refrigeration systems.
• Ecocent: A monobloc Air Source Heat Pump and hot water storage cylinder from Earth Save Products Limited, which harvests waste thermal energy and uses it to heat hot water for domestic purposes.