Type of works: supply of EcoCooling evaporative coolers.

Farmfoods are specialist frozen food retailers operating over 300 outlets throughout Great Britain. This competitive environment requires low-capital cost and low-operating facilities. The future implications of the Carbon Reduction Commitment program also have to be addressed.

A significant component of operating cost for the stores is the cost of air conditioning. Food is stored in Novum freezer cabinets which give out heat as part of their operation. The existing cooling option was to use conventional split air-conditioners to keep the store cool. Since the Novum freezers run 24 hours per day, 7 days per week, there is a continuous requirement for cooling and the refrigeration-based air conditioning consumes over 50% of a typical store’s electricity use.

In a typical store, 60kW of air-conditioning equipment is replaced by 2 EcoCoolers. The control system enables the air conditioning if any in-store temperature or humidity parameters are not met. The management of humidity levels is critical in this installation to minimise condensation on the single glazed Novum freezer lids. A control system was developed to manage the ventilation and evaporative cooling modes to address this issue.

Air is ducted into the store from the EcoCoolers with axial extract fans, forming a balanced ventilation system. Due to building construction restrictions, most stores have a cross flow ventilation scheme. With thermostats at both the front and back of the store, the temperature gradient is controlled.

A number of Farmfoods stores have an intranet-based building management system. This has shown an electricity saving of over 50% where EcoCooling has been employed.