Metro, Sofia

DEVI ice and snow melting systems provide safe access to the Sofia Metro

In order to provide its passengers’ protection from the effects of the bitter Bulgarian winter, the Sofia Metro installed a range of snow and ice protection systems.

The stairways at the entrances and exits of three central metro stations in Sofia are equipped with state-of-the-art DEVI ice and snow melting systems. The solution is beautifully simple: 11,550 meters of heating cable installed in the steps of the new stations, providing total ice and snow protection for the Metro’s many users.

 A satisfied customer

The installation was handled by Trace Group Holding, whose project manager, Boyan Deltchev, explained the reasons for choosing DEVI: “The new DEVI ice and snow melting systems are both precise and economical. The systems are a boon for the high-traffic central metro stations, ensuring passenger safety on open stairways. Canopies alone are not enough to provide reliable protection against slippery or icy steps. It is also great that the anti-icing systems operate fully automatically. They detect the need for snow melting and operate only when necessary.” Thanks to the intelligent digital sensors for humidity and temperature, the systems operate very precisely with minimal energy consumption.

“Another advantage of the systems is that the heating cables are easily installed under the covering of the steps. This does not affect their design in any way or require any changes to architectural plans. I think that cable heating solutions will be used more extensively in the execution of the coming phases of the Sofia Metro expansion project, since they are effective and economical. Their benefits will be apparent in the next winter season, after the new metro stations are put into service.”

 Strong growth potential for DEVI

Vera Bardarova, Sales Director of DEVI Bulgaria, emphasized that DEVI was specifically chosen for their unrivalled expertise in this area. Trace Group was looking for a highly-reliable system that would operate automatically and prevent accidents caused by icy steps and pavements. As Bardarova explained, “For Trace Group, the most important considerations were the high quality of DEVI products, the 20-year warranty, and the excellent technical and service support provided by our experts.”

 Extremely effective and economical

The metro’s new ice and snow melting systems operate fast and completely automatically. The advanced control concept provides high performance while keeping operating costs low.

The digital sensors constantly monitor weather conditions and provide real-time information to the DEVIreg™ 850 microprocessor controller. This ensures that the system is activated during snowy and icy conditions but is switched off when the weather is dry – even in very cold periods – thus saving valuable energy. The DEVIreg™ 850 controller operates with extreme precision to reduce power consumption. This reduces energy consumption to a minimum without compromising the high level of safety provided by the system.

 A rapidly developing sector

More and more customers are coming to understand the clear benefits offered by ice and snow melting systems. The sector grew by 32 percent in 2011 and DEVI sees enormous potential for the future. Henrik Londorf, Director of Markets, Portfolio and Strategy at DEVI, explained the background to this growth: “These solutions help us meet a wide range of weather-related challenges. Structural damage to roofs caused by heavy falls of snow is just one issue. Alongside that are things like frozen gutters and burst water pipes as well as the building damage they cause. And then, there are issues like icy stairways or pavements in public areas with high traffic, such as the Sofia Metro. These are just some of the many practical problems that our systems either mitigate or entirely eliminate. Many municipalities, companies, and property owners realize that it is extremely worthwhile to invest in technology that actively prevents serious damage or injury, thereby saving money in the long term.”

The complete DEVI snow and ice melting system has a total rated power of 233 kW and protects 780 square meters of stairway against ice and snow. The highly effective system is controlled by a total of eight “intelligent” DEVIreg™ 850 thermostats equipped with microprocessors. In addition, 28 digital sensors constantly monitor weather conditions.

Metro station 9-II “NDK”:

  • 190 m² of external stairway are protected against icing by 2,800 metres of DEVIsnow™ 20T (DTCE) heating cable with a total rated power of 56.5 kW.
  • The system is controlled by three DEVIreg™ 850 thermostats with microprocessors and eight digital ground sensors.

Metro station 10-II “Sv. Naum”:

  • The installed system area is 450 m² with 6,700 metres of DEVIsnow™ 20T (DTCE) heating cable with a total rated power of 135.5 kW.
  • The system is controlled by three DEVIreg™ 850 thermostats with microprocessors and 12 digital ground sensors.

Metro station 11-II “James Baucher”:

  • The ice and snow melting system covers 140 m² of stairway with 2,050 metres of DEVIsnow™ 20T (DTCE) heating cable with a total rated power of 41 kW.
  • The system is controlled by two DEVIreg™ 850 thermostats with microprocessors and eight digital ground sensors.

Project Overview:

  • Total size: 780m2
  • DEVIsnow™ 20T – 11,550 m
  • DEVIreg™ 850 – 8 pcs
  • Ground sensors – 28
[Project Size]


Нагревателни кабели
DEVIsnow™ 20T
DEVIsnow™ е изключително високо качество, 360° напълно проверени близнак диригент кабел с трудна външна обвивка (UV стабилен). Неговата кръг профил и здрава конструкция осигурява по-бърз, лесен и сигурен монтаж върху покриви, в олуци, водосточни тръби надолу и на земята. Студеният преднина има твърди проводници, осигуряващи бърз монтаж с ясно видима връзка. За да се осигури по-дълъг живот работно време, всички кабели са щателно проверени, включително тестове за устойчивост омичен, високо напрежение и материални проверки за осигуряване на качеството. Това означава, че ние сме горди да доставяме на нашите удължен DEVIwarranty™.
DEVIreg™ 850
В Devireg ™ 850 е модерна термостат с LED дисплей, използван за открито наземни или покривни приложения. Сензорите предоставят информация за едновременно ниво на влажност и температура, което води до оптимално управление на отоплителната система. Системата може да бъде създадена по три начина; като единна система за покрив или смлени (1 до 4 сензори), като двойна система за покрив или смлени (2 - 4 датчици) или като комбинация система за покрив и земята (2 - 4 сензори). В системите за двоен / комбинация е възможно да се приоритет между зоните, например ако само ограничен изходна мощност е на разположение.