Archive for January, 2011

Steam against snow, also on the roof

Saturday, January 1st, 2011

As in 2009 the present winter 2010/2010 is extraordinarily snowy. Streets and paths need to be cleared, masses of snow pile up to big mountains. Where to put it?

On German roofs the situtation here and there gets serious. Snowslides become a threat. Snowloads of 30-60 kg per m² roofage are critical. Many flat roofs are in danger of imminent collapse. The result: Communities are forced to close down larger halls and buildings in order to avoid catastrophes.

Industrial plants also need to clear their flat roofs which causes high cost. Hot steam may be an appropriate solution to get rid of snow quickly and cost efficiently.

With steam it’s possible to kill two birds with one stone. On the one hand the roof gets cleared of snow quickly without high labour cost, on the other hand snow simply flows down the roof rail with a temperature of ~6°C at reduced volume as water and doesn’t need to be removed.

Energy cost for melting snow is rather low. In order to melt about 100kg (=~1m³) of snow about 33.500 kJ (=8.006,5 kcal) are needed – this is equivalent to the energy contained by less than one liter fuel oil.

When comparing the steaming method with conventional clearing methods the cost advantages gets obvious. One person clears about 8-10m³ (=800-1.000 kg) snow on average per hour. If an hourly rate of only 20EUR/h is used clearing cost (without snow removal) of about 2 EUR/m³ arise. Furthermore powerful steam generators are able to melt up to 16.000 kg of snow per h (=~16 people).

The use of hot steam is quite simple: Through perforated pipes or hoses, which can easily be layed out on the roof, steam is induced and penetrates the snow. Snow melts. In order to improve efficiency snow can be piled up on top of the steam pipes.

A small demonstration by MSD / Germany illustrates the method how bigger amounts of snow can be easily cleared:

Steam fork with perforated pipes underneath a pile of snow

Steam fork with perforated pipes underneath a pile of snow

1. Underneath a big pile of snow a steam fork gets installed. Steam is induced from a steam boiler through steaming hoses. In this example a steam output of 500kg / h is used.

Steam is induced underneath the snow.

Steam is induced underneath the snow.

2. Through the steam fork steam is induced underneath the snow and exits through holes in the perforated pipes.

Steam exits

Steam exits

3. Here and there steam finds its way to the surface. It is recommended to close such gaps with snow in order to increase efficiency until snow is completely melted.

Please request more information directly at MSD GmbH from Durbach using the email address : info@moeschle.de .