During the fall of 2016, Magged Khalidy, Franchisee at Burger King in the south of Sweden, was looking for ways to lower the heating costs at his restaurants. He was approached by a new company (Enjay) who claimed that they had found a way to recover the heat in the hot exhaust air from the kitchen and then use this energy to pre heat the cold supply air going into the restaurant. Without any extra maintenance.
Even though Magged believed it sounded too good to be true, he decided to give it a try.
Now, 7 years later, this technology (Lepido) is not only installed at all Magged’s restaurants, it is also standard equipment at all new Burger Kings being built in Scandinavia.
The system recovers about 85.000 kWh per year and restaurant. And with no extra service required, every recovered kWh means one less kWh that needs to be purchased from the grid.
Lepido is an Innovated & Made in Sweden air-to-fluid heavy duty heat exchanger, specially designed to be deployed in polluted air streams. It is developed for mounting in the duct, without any requirement for pre-filtration.
Contrary to a standard heat exchanger, where the natural forces constantly work against keeping the unit clean, the Lepido interior is designed to work with the natural forces. It involves a geometry that is fin-less and allows for more spacing than a traditional heat exchanger.
To accommodate the patented geometric design, which consists of coils only – no flat surfaces, no fins – Lepido is deeper/longer than a traditional heat exchanger.
Heat transfer surface in a Lepido is still comparative to a standard heat exchanger with fins.
Sweden vs. The UK
This example is from a Swedish restaurant, so how does this apply to the UK? Even though there are a lot of differences between the HCAV systems in Sweden and the UK, Lepido is absolutely suitable for the UK. In Sweden the recovered energy often replaces central heating or heat pumps. But in UK, the energy would replace the electrical heating battery (EHB). So, recovering 85.000 kWh at a restaurant in the UK, with a cost per kWh at £0,3, the yearly savings would be £25.500.