Hot water heating with solar system for the main kitchen

Initial situation:

St Mary's Hospital Lacor is located in Gulu in northern Uganda. Firewood or charcoal is traditionally used for cooking in this region. This usually leads to massive deforestation and soil erosion. The increasingly heavy rainfall caused by climate change is eroding the nutrient-rich top layer of soil.

The kitchen at St Mary's Hospital Lacor prepares around 400 meals a day, mainly for the midwifery and nursing students. The aim of this project was to drastically reduce the consumption of firewood through the use of renewable energy.

Solution:

As there is a relatively high level of solar radiation in Gulu almost every day, it quickly became clear that water for the kitchen could be heated using solar energy: Solar thermal or via Photovoltaic ("Power to heat" with electric heating elements and corresponding control). Due to the simpler technical implementation and lower maintenance requirements, the decision was made in favour of solar power with electric heating rods in the water tank. The water, which heats up to 70 °C - not more for safety reasons - is channelled directly to the large cooking pots. As before, additional heating is provided by firewood, which the cooks are used to anyway. The amount of firewood saved is around 70 %, which is about 300 kg per day!
 

Main components installed:

• 19.8 kWp solar panels
• 20 kW solar grid inverter
• 2 x 1000 litre hot water tanks
• 17 kW heating elements
• Controller and monitoring system

For smaller kitchens it is even possible to cook 100 % electrically. This can be realised with a combination of stoves, hot water boilers and solar power, with or without battery storage or grid connection. The advantage is that most of the existing infrastructure can be used. One disadvantage is that these cookers may not be able to be operated efficiently during the rainy season or when there is little sunshine - depending on the availability/capacity of the power storage units or connection to a power grid.