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Reference project

Vasakronan improves energy efficiency with ozone

Air purification waste room
Stockholm, Sweden
Property for shopping and student housing
70 m3/h


A quick payback in just three months

Vasakronan, Sweden’s largest real estate owner, manages and develops centrally located office and retail properties in all major cities in Sweden. Vasakronan is owned by the four public AP pension funds.

The company’s property portfolio comprises 183 properties with a total area of 2.5 million square meters. The majority of the stock is located in Stockholm, where Skrapan on Södermalm is one of the properties owned and managed by Vasakronan.

The “Tax Scraper” is a famous Stockholm building, designed by the renowned architect Paul Hedqvist. When the Swedish Tax Agency moved out, the Tax Scraper was rebuilt to make room for student housing. In September 2007, the new mall, which is on the ground floor, was inaugurated. The building was initially 24 storeys high, but two floors with a restaurant and sky bar have been added in connection with the refurbishment. Today, in addition to student housing and offices, there is a wide and appealing store mix and a large selection of cafes and restaurants.

The problem.

Food waste from restaurants often creates inconveniences in the form of bad odors and bacteria. Properties with commercial restaurants are required to have a room for food waste. The room needs constant supervision to minimize disturbing odor emissions, bacterial growth, flies, insects and pests. The municipal waste regulations previously required that food waste be stored refrigerated. The scraper achieved this using a 6.3 kW cooling unit which lowered the temperature to five degrees Celsius to reduce bacterial growth.

Since then, the waste regulations for the municipalities have changed and alternative solutions to the cooling units were allowed.

The solution.

We contacted Vasakronan in conjunction with the rebuilding of the Tax Scraper, but the decision to purchase and install a conventional cooling unit for the 70 sqm waste space was already taken. At our initiative, a comparative study was conducted between a cooling unit and an ozone generator. The study showed that cooling can advantageously be replaced by ozone.

The benefits of replacing cooling with ozone were obvious immediately and were also permanent, which resulted in Vasakronan tearing down the cooling system and the entire odor purification is now handled by a Ozonetech ACT series ozone generator.

An ozone system purifies the air with the help of ozone (O3) which quickly breaks down viruses, bacteria and odors. The ozone system produces ozone on site from the ambient air. Nothing needs to be bought, transported, stored or refilled. The purification of the air in the waste room begins immediately when the ozone system starts.

Solution facts.
Mellifiq delivery
Ozonetech ACT-series
Dimensions (HxWxD)
225 x 100 x 80 mm
Input power
0.018 kW
Noise level
28 dB
2 kg


The system solution with both low investment costs and low service and maintenance costs, saves big money for Vasakronan. The energy consumption is only 18 watts, which means an energy cost of only 30-40 USD per year compared to the energy cost of the previous solution of several thousand USD per year.

In addition to the economic benefits of the new air purification in the waste room, Vasakronan sees additional benefits: the odors have been minimized and the quality of the air has increased.