Solar powered grain mills to improve food security

Usually, grain mills are operated with internal combustion engines (mostly diesel), whereby people in the immediate vicinity are exposed to the high levels of noise and exhaust gas emissions. In addition, the supply of fuel can be a major problem due to high prices or lack of availability. But it doesn’t have to be like that! Solar-powered mills are particularly suitable for regions without a connection to the power grid: they are more cost-effective to operate and without CO2 emissions.
BBM delivered two solar mills to Borzanga (Burkina Faso) on behalf of Caritas of the Diocese of Innsbruck (Austria), the installation being carried out by a local team of technicians.


Technical Specification:
  • Solar mill with 1.5 kW electric motor (DC and AC operation possible)
  • 2.1 kWp solar power
  • Granite millstones (500mm diameter)
  • Throughput approx 25 kg/h



Renovation of St. Francis Hospital, South Sudan


St. Francis Hospital in Marial Lou is the major hospital in the region. The hospital has changed their activities from an emergency hospital to become a permanent hospital for the surrounding communities. And also the number of patients has constantly increased over the last years.

The handed over structures from MSF (Médecins sans Frontières) are all non- or semi-permanent structures. The life span of such structures is normally between 3 to 15 years. Within this period, all buildings must be renewed or renovated.

The existing operating theatre is a non-permanent structure using mud bricks as walls and inadequate floor, ceiling and roof constructions. Open windows are the only ventilation system.
It is not possible to fulfil minimum hygienic standards with this situation.


Proposed technology for new operating theatre:

The new operating theatre is planned based on international hygiene standards and norms. The major technical aspects are:


Patient handling cycle:

There is a separate patient handling cycle which allows

  • the preparation of the patient (pre-operation)
  • the proper operation in the operating theatre
  • to keep the patient for some time in the recovery / ICU room (post operation)
  • and finally to move the patient to the ward through the exit room


Staff cycle:

  • separate entrance for staff
  • shower and washing basins
  • staff room
  • transfer room
  • separate entrance to operating theatre


Equipment / Material cycle:

  • including scrubs / wash up
  • transfer room
  • sterilization room


High quality building standard:

The building has basically two different sections: one is the centre with air condition and all other rooms are with natural air flow. The walls are made of burnt clay bricks (Uganda clays) isolation from the outside heat. The cold part of the building is made out of double walls in order to keep the cold inside the rooms. All floors are with special floor tiles and the walls with wall tiles. The inner height of the operating theatre room is 3 mts standard height in order to keep space for the special installations and head lamps.


Roof – partly a flat roof

The flat roof covers the higher part starting from the preparation room until the exit room. All auxiliary rooms are covered with a high quality corrugated iron sheet. Photovoltaic panels are covering the flat roof fully for supplying power to the cooling unit as well as the operating theatre battery system. Doors and windows: from Europe for a perfect closing and air tightness


Operating theatre ventilation system:

European standard ventilation system for operating theatre. The air pressure inside the operating theatre rooms is controlled and excess pressure does not allow inflow of dust from outside. Photovoltaic system: The proposed operating theatre is fully self-reliant, no need for the generator or any other power generation apart from installed solar array. The system is composed of 14400 WP solar field supplying 3 grid interactive inverters. For larger solar systems that generally supply to AC consumers, it is more efficient to immediately invert the solar power into AC. Therefore we call these systems “AC systems”. AC systems have higher energy efficiency in comparison to other systems. The Grid Inverter directly converts the solar energy into AC. All excess solar power which isn’t used by the AC consumers is used to charge the batteries.


Cooling unit:

The operation time in the operating theatre will depend on the scheduled and unforeseen emergencies within the hospital. Technically, electrical energy can only be harvested during sunshine, mainly between 8 am and 5 pm of a day. During this time, PV electrical energy can be used directly (light, ventilation, OP equipment, cooling compressors etc.) or can be kept in an electrical storage = battery. Cooling takes normally a lot of energy and therefore in the concept of this operating theatre, the cooling energy will be kept as cold water in a 5000 lts water storage under the floor of the operating theatre building. Night operations can be done without any need of electrical power for the cooling compressor / air conditioner.


Light circuits:

Flicker free lights are foreseen for all rooms (energy saving)


Electrical protection circuits:

  • Based on international standards
  • Power is used only from solar
  • Excess power can be used during daytime for instrument sterilization


Water and wastewater:

  • Water basins and valves are made out of stainless steel
  • Water is connected to the main hospital water supply
  • Waste water is connected to the main sewer line of the hospital


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