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Mongolia: Heating with solar power
atmosfair finances and installs photovoltaic systems and electric heating systems in Mongolia, enabling institutions such as kindergartens and schools to switch from heating with environmentally harmful and unhealthy coal to solar power.
The solar systems are designed in such a way that they produce as much electricity over the year as is needed for heating. In winter, additional electricity is to be drawn from the grid and in summer the same amount of solar power is to be fed into the grid.
Electric heating
The first two solar-electric heating systems were put into operation at the beginning of October 2023. These are “twin” kindergartens in Ulaanbaatar, i.e. two kindergartens at the same location in two neighboring, virtually identical buildings. Here we test two approaches to electric heating:
Kindergarten A uses a water-based heating system with heating rods to convert the electricity from the 50 kWp PV system into heat. This is temporarily stored in latent heat storage units, in which the heat is stored when waxes melt and released again when the waxes harden. This allows solar power to be used effectively in winter even without feeding it into the grid. The heat is conducted in insulated water pipes to the radiators in the individual rooms.
The second heating system in kindergarten B uses the electricity from a 20 kWp PV system to heat the individual rooms directly and efficiently with 19 air-to-air heat pumps. As the name suggests, heat pumps pump heat from the outside air into the indoor air of buildings. In a compressor circuit, a refrigerant is evaporated by low pressure in the outdoor unit of the air conditioning system. In doing so, it extracts heat from the ambient air. This also works at sub-zero temperatures. The coolant is compressed and condensed under high pressure in the indoor unit of the air conditioning system. The heat is dissipated into the indoor air. If an air conditioning system is operated in cooling mode, the process is reversed. Commercially available refrigerators work on the same principle.
As early as 2019, a study involving a total of 7 households showed that efficient heating with modern air conditioning systems is possible even in very cold Mongolia[1]. Even at the lowest temperatures, the air conditioning systems were still slightly more efficient than heating rods (100% efficiency) and produced an average of 2.8 kWh of heat for every kWh of electricity during the entire heating period. This is also referred to as an SCOP (seasonal coefficient of performance) of 2.8. In Germany, values between 4 and 5 are possible due to the milder winters. The PV system for kindergarten B could therefore be dimensioned smaller than the one for kindergarten A.
Mongolia and solar energy
Mongolia covers around 90% of its heating energy with domestic coal. In addition to the immense environmental and climate impacts, air pollution, which is primarily caused by burning coal, is responsible for around 3300 premature deaths every year in Ulaanbaatar alone[2]. Switching to solar-electric heating can be a sustainable solution.
Winter in Mongolia is cold. With an average annual temperature of -2°C and lows of up to -40°C in winter, Ulaanbaatar is the coldest capital city in the world. At the same time, photovoltaic systems produce approx. 1.8 times more electricity than systems of the same size in Germany (approx. 1800 kWh/kWp/year vs. 1000 kWh/kWp/year) due to the stronger solar radiation at lower temperatures. If the solar systems are elevated at a steep angle (45-50°) and oriented to the south, they produce as much electricity in winter as they do in summer in the high-altitude areas of Mongolia. In comparison: in Germany, the solar output in winter drops to approx. 1/3 of the output in summer. This means that around 75% of solar power can be used for heating in Mongolia, even without seasonal storage.
Outlook
Once the two different electric heating systems have been evaluated after the first winter, the project will be extended to other institutions. In order to reduce the subsidy share and enable scaling, the feed-in tariff for the solar power produced will be of decisive importance in the future, in addition to cost optimization.
Kindergarten project
Clean heat project for kindergartens in cooperation with atmosfair and the NewClimate Institute (NCI) and kraftBoxx GmbH.
