Usefulness and Efficiency in Connection with Energy Savings

Comparison of Purposeful Electricity Consumption in Different Types of Kitchen Operations

This data is taken from measurements conducted in Switzerland: Restaurant MIGROS, Hospital, Retirement Home, Fast Food with Air Conditioning

Yellow: Lighting
Light blue: Ventilation
Dark blue: Cooling
Pink: Dishwashing
Red: Hot Kitchen

 

Ventilation equipment consumes on average almost a quarter (23.2%) of the total electricity consumption in kitchen operations, making it the second largest "consumer" after the thermal food preparation. The high share of electricity consumption by the ventilation system suggests that by choosing appropriate ventilation with increased extraction efficiency, significant savings in operational costs can be achieved.

 

Acquisition costs

The diagram of acquisition costs has general applicability and can be used to select the most cost-effective investment solution. The approximate course of average acquisition costs was derived and extrapolated after evaluating three bids for kitchen ventilation in Switzerland between 1989 and 1991. The listed bids included both variants, namely for two restaurant kitchens and for one kitchen in a children's hospital. The first variant always involved conventional ventilation with full air volume, while the second variant used a ventilation system with EKO covers INDUCTair® (covers with injected air) and a legally approved reduction of the air volume by 30%. It is necessary to consider price ranges, price development, and inflation in the compared countries, as well as the varying potential reductions in air volume.

 

 

Total acquisition costs (AC).

For the kitchen ventilation, including the supply and exhaust system, air fittings, exhaust fan, heat recovery exchanger, terminal units including exhaust enclosures with accessories (such as grease filters, built-in lighting, possible components of the injection system), including transportation of all devices, equipment, and materials for construction, installation, commissioning of the equipment, etc.

 

Example Unsuppressed Extraction (m³/h) Suppressed Extraction (m³/h) Initial Investment Costs with EKO Hoods (ΔPN)
Example 1 8000 5600 ΔPN Lower
Example 2 4200 2940 PN Approximately Same
Example 3 2800 1995 PN Significantly Lower

Note: Example 3 pertains to a small kitchen.

By using INDUCTair hoods with reduced air extraction, it's possible to implement a so-called "vacuum extraction" system without the need for a supply air system, significantly reducing the overall ventilation costs. Additionally, this approach eliminates the need for heating water circuits, control technology, and electrical installations. However, it's essential to ensure controllable intake of replacement air, either from the outside or adjacent spaces, and to provide filtration and heating of this air using heating elements.

 

 

 

INDUCTair® = high efficiency = energy savings = short payback period

a) When the ventilation rate is reduced by 25% in INDUCTair® induction hoods, which can be approximately 2,000 m³/h for a medium-sized restaurant kitchen, it requires around 27,000 kWh of energy to heat the replacement amount of incoming air in winter, assuming 80% heating efficiency, 200 days of heating season, and a temperature difference of 16°C. The operating cost savings for heating the incoming air with water-gas heating are approximately 32,000 CZK per year, and with electric heating, approximately 72,000 CZK per year

 

b) The lower electricity consumption of the fan drive is also not negligible – for example, 1 kWh for the power consumption of the electric motor of the main exhaust duct x 10 hours/day x 365 days/year x 3 CZK/kWh = 10,950 CZK per year

The return on investment for the INDUCTair® induction range hood, with a price difference of 50,000 CZK between a non-induction and induction hood, is only in direct costs:

approximately 14 months

By simply reducing the ventilation rates for kitchens by about 25-30%, we achieve the return on the increased investment costs for the highly efficient induction range hood in

4 years

c) The increase in investment costs when using hoods with an induction system is also partially eliminated (in many cases, this is a limiting factor) by smaller pipe cross-sections and, most importantly, smaller HVAC units, which is advantageous and often the only solution when renovating old and historic buildings with limited space for HVAC installation.

(The article was part of a lecture at the seminar "Ventilation of Kitchens," Prague 2016)