Subway restaurants in Northern Ireland cut hot water costs with Activair air source heat pump

(12/03/2009)

The franchisee for a chain of Subway restaurants in Northern Ireland found it could cut the annual cost of providing hot water in a typical restaurant following trials of Trianco's Activair air source heat pump (ASHP).

The company that operates franchises on a network of nine Subway restaurants in Northern Ireland called in Belfast-based company The Energy Centre to monitor electricity usage and suggest more efficient and environment-friendly options.

Gordon Laverty, managing director of Renewable Energy Solutions & Advice Ltd, which runs The Energy Centre, said: “The Subway restaurants used two 3kW electric immersion water heaters with mainly 100-litre tanks. I realised that this must be costing the company a fortune to provide hot water.”

The Energy Centre provides domestic users and businesses with energy efficiency advice, consultant and showcases heating technologies. It installed meters in four of the Subway restaurants, which recorded an average daily consumption of around 50kW a day, equivalent to an annual electricity bill per restaurant of around £3,100 for their hot water.

Next, The Energy Centre installed an Activair air source heat pump on a one-month trial within the kitchen at the Subway restaurant in Glengormley, near Belfast, where usage was highest. The unit operated for around 11 hours a day and achieved respectable COP levels. Electricity consumption here fell dramatically to just 10.5kW a day – saving the franchisee an impressive approx £2,500 a year.

“The franchisee has now asked us to run tests on its other restaurants with different size boilers and insulation. We will also be looking at restaurants that operate 24-hours a day and need hot water around the clock,” said Gordon Laverty. He added: “Subway is always looking at ways to promote healthy eating and reduce its impact on the environment. Focusing on renewable energy is a natural step for the company to take.”

The Energy Centre selected an Activair ASHP for the trial and was so impressed with the results the unit is now displayed in its showroom. “Trianco is a well-established company with top-class products. They only use high quality products and their service is second to none. They deliver quickly and are very price conscious, recognising that renewable energy products have to be affordable if they are going to take off in the UK,” said Laverty.

From its base in Mallusk Enterprise Park, Belfast, The Energy Centre showcases a range of renewable and energy efficient systems, including solar and air source heat pumps, underfloor heating as well as insulation products.

“We can’t switch every household and business completely to renewable energy sources as it is not yet practical to do so. Our approach is that if we use fossil fuels, let’s do so wisely,” said Laverty. Since opening The Energy Centre last August, sales have been phenomenal. We wanted to include air source heat pump technology and are delighted to be involved with Trianco.”

The Energy Savings Trusts in Northern Ireland recommends that domestic users and companies visit the Energy Centre to view the wide range of environment-friendly products and systems that are now available.

The Energy Centre was able to convince Subway about the cost-saving benefits of the Activair immediately it was installed.

The Activair only needs a very small amount of electricity to drive a fan and a quiet, low vibration compressor. From the surrounding air, it extracts large quantities of low grade, otherwise wasted, warm air and converts it using an exchanger and a fan into heat for domestic heating and hot water.

The Activair blows out cool air so Subway staff were able to turn off the air conditioning unit normally used to keep them cool in the hot kitchen. “Instead, they said they noticed a real benefit from the cool air circulating from the Activair and saved even more money on their electricity bill,” said Laverty.

According to Trianco, the low-maintenance Activair can be 50% cheaper to install than a solar source. The unit only weighs around 40kg, so it is quick and easy to install that only requires annual maintenance to support it. “It took our engineer about two and a half hours to install at Subway for the trial,” confirmed Laverty.

For the Subway pilot, The Energy Centre added a solar siphon that provides power to heat water externally from the man boiler. “The advantage of adding a Willis solar siphon is that it puts hot water into the top of the tank, so there is always a quantity of hot water ready to use. We believe this increases the efficiency of the system even more,” said Laverty. “The Subway pilot trial proved that air source heat pump technology delivers real cost savings and environmental benefits.”

Related categories:  Commercial and offices applications   Energy Conservation   Heat pumps   Hot water generation and supply