The green route to efficiency

The past year has certainly been a rich one in terms of energy efficiency news and developments and as the need for stores to keep a lid on their overheads becomes ever more pressing, 2015 looks set to be tinged with an even more vivid shade of green. Here’s a round-up some of the clever technologies, which when used alone, or collectively, can take the biggest bite out of your energy bills.

CHILLER DOORS

The use of doors on chillers has soared in the past year and they are now a default specification for most new-build symbol group stores as well as stores undergoing any refurbishment.

And when you consider the benefits, it’s easy to see why. In addition to reducing energy consumption by about 33%, doors also create a more comfortable temperature in the aisles. Early fears that doors might act as a barrier to sales are not being realised. In fact, many retailers are reporting reduced shrinkage and, when used in conjunction with LED lighting in the chillers, improved product standout.

Convenience Retailer of The Year David Charman, who had doors fitted to chillers in his Spar store in West Malling, Kent, last year, is adamant that doors are not an obstacle to sales. He calls the act of opening the door “a commitment to purchase”.

Doors also facilitate the use of natural refrigerants such as hydrocarbons which, due to their flammability, are subject to stringent charge size limitations. The reduced electrical load on closed refrigeration systems means that the same cooling can be achieved with a smaller refrigerant charge size.

From acrylic to glass, hinged or sliding, there is now a wide range of options for retailers to choose from. Hinged doors are thought to be more suitable for stores with wide aisles, while sliding doors are a good option for stores where space is restricted.

Glass is widely believed to be easier to keep clean and its thermal performance is thought to be better. However, thanks to new double-glazed varieties, acrylic doors are gaining in popularity. The double glazing is thought to make the doors more efficient and reduce misting.

Acrylic’s lightweight properties also allow for frameless solutions, which increase product standout, while hinges have a longer shelf life.

Delta Refrigeration Services has just added the new Total Vision Acrylic Door system from Thermasolutions to its range. The frameless double-glazed door provides a larger opening into the display cabinet and is said to offer better energy savings over a single-glazed equivalent.

Acrylic doors are, however, more prone to becoming scuffed and scratched than glass, and as a result Delta is offering retailers a recycling service for acrylic doors after five years.

The Southern Co-operative has installed aluminium framed glass double-glazed doors in about a third of its 200-strong store estate. However, it is also looking to test double-gazed frameless acrylics in selected outlets.

DON’T FANCY CHILLER DOORS?

For retailers still not open to the idea of doors on chillers there are other efficiency solutions available for refrigeration, such as Enviroglow’s Chillscoops. These are small plastic ‘scoops’ which are retrofitted onto chillers, where they catch up to 90% of the cold air being blown out from the chillers and direct it back into the refrigerated airflow.

While Costcutter tends to recommend retrofitting glass doors to chillers, head of store development Antony Downing believes that scoop technology is an increasingly good option for retailers. “There are many options available and some of the most energy efficient chillers currently available do not feature doors and instead use the latest scoop technology to minimise energy wastage,” he says.

Earlier this year Enviroglow took its Chillscoop technology one step further with the launch of the E-volve open-deck refrigeration system. The E-volve unit, which uses ChillScoop technology to reduce energy consumption, is said to be 54% more efficient than a standard open-deck chiller system and up to 26% more efficient than fridges with doors used in live environments.

NATURAL REFRIGERANTS

The use of natural refrigerants in place of climate-harmful refrigerants such as hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs) is already on the rise in the UK and is set to dramatically increase from next year when new laws banning some of the more potent greenhouse gases come into force.

Much less harmful to the climate, natural refrigerants are also often cheaper and more energy efficient than their counterparts. As their name suggests these ‘natural’ refrigerants are substances that occur in nature.

The three main natural refrigerants in use are hydrocarbons, ammonia and carbon dioxide (CO2). In spite of its notoriety as a greenhouse gas, CO2 has very positive characteristics as a refrigerant and is fast becoming the natural refrigerant of choice for many retailers. In Switzerland, where legislation bans the use of HFCs in most commercial applications, Co-op Schweiz has converted one-third of its stores to CO2 refrigeration and is reporting energy efficiency gains of almost 30% over HFC-based systems.

Sainsbury’s is now using trans-critical CO2 in more than 160 of its supermarkets and is currently testing small transcritical CO2 systems in convenience stores following a trial in a Sainsbury’s Local near Birmingham, which reduced greenhouse gas emissions by 33% and increased the store’s overall energy efficiency.

Hydrocarbons are another type of natural refrigerant. Musgrave has been trialling hydrocarbon integral units for chilled food, with trial stores reaping energy savings of about 40% so far.

HEAT RECLAIM

The use of heat-recovery techniques can significantly reduce energy consumption, running costs and carbon emissions.

In a nutshell, systems work by harnessing waste heat rejected from refrigeration and air-conditioning systems and intercepting it before it is vented out into the atmosphere. This waste heat can then be used to deliver potable or hot water at 45-600C.

According to DK Heat Recovery, almost 90% of a c-store’s hot water demands can be supplied by heat recovered from refrigeration.

Heating 1,000 litres of water to 500C costs between £1.50 and £4.50 depending on the energy source used to heat it, but by recovering waste heat from refrigeration or air conditioning this can be reduced to zero - and you’d be amazed how much hot water a typical c-store uses, particularly larger stores with a food-to-go offer.

Installations often have a payback period of as little as two years and the systems can also prolong the life of a boiler.

The Village Store in Wangford, Suffolk, was fitted with an EcoTherm heat recovery system from British company Secker and Sons earlier this year. It produces 120 litres of hot water overnight and 60 litres every hour throughout the day.

VOLTAGE OPTIMISATION

Most in-store equipment needs only 220V to run. However, voltage levels from the National Grid are often much higher than this and can peak at 250V. This discrepancy means that stores can be using far more voltage than they need to run equipment - and paying unnecessarily high bills as a result. Voltage optimisation works by regulating the level of voltage which supplies a store’s electrical equipment and appliances.

According to British company VO4, voltage optimisation technology can achieve energy savings of about 15% - usually resulting in a return on investment in less than three years.

It can also help save money by protecting a retailers’ equipment and extending its lifespan, as higher voltages can lead to greater heat generation in motors, reducing the lifespan of many electrical items, even light bulbs.

Dilip Patel installed Ecomonitor’s eco-system360 in his Northampton Premier last year and has seen his energy costs fall by 18% as a result.

VO4 also manufactures a range of voltage optimisation systems ideal for convenience stores. Available in 10V, 15V and 20V models, the VO4 100Amp 3 phase system has helped Londis Nafferton, Yorkshire, to reduce its electricity use by about 14%, clocking up savings of £1,354 per year.