The best practices in the choice, sizing and installation of biomass heating systems shared by Norsk Energi experts in Chișinău
On February 6-9, companies specialized in biomass plants installation, service companies and system engineers, as well as students of the Technical University, Centre for Construction Excellence and the College of Technology of Moldova attended a specialized training on best practices in choosing boilers and the type of biofuel, in the sizing and installation thereof, as well as on the advantages and disadvantages in terms of capital and operating expenses.
The workshop was facilitated by the experts from the Norwegian company Norsk Energi with the support of the Energy and Biomass Project, funded by the European Union and implemented by the United Nations Development Programme.
According to Norwegians experts, the design of the plant and its capacity depend not only on the type and size of the building, but also on a number of its technical parameters. Thus, for instance, schools imply the availability of large, crowded rooms, hospitals – smaller rooms, with less people per square meter, this particularity also depending on the amount of heat released by the human body in heated spaces. At the same time, older buildings with poor thermal insulation need about 100-200 W/m2, while a proper insulation reduces the consumption to about 30 W/m2. Old radiators require water temperature of 80-60 degrees Celsius, modern convectors and radiators – 60-40 ⁰C and the buildings with underfloor heating – just 40-25⁰C.
For the heating of several neighboring buildings, Norwegian experts recommend operating a district heating system, a larger number of consumers connected to the same network implying a lower capacity of the heating plant in relation to the theoretical maximum of the heat flow. This applies to both domestic hot water use and to heating appliances, since the basic rule of a centralized heating system is that more than 80% of consumers will be connected concurrently.
Moldovan experts have analyzed the benefits, the particularities of sizing and installation of heat expansion tanks and hot water tanks. Use of the tank hot water ensures both operation at a constant capacity of the boiler and constant water consumption during peak hours, in the morning and in the evening, and in the summer it can provide for the hot water needs for a few days with only 6 hours of boiler operation. In addition, a system of solar collectors can heat water, which will be kept warm for the rainy days.
The size of the heating system components is equally important for its effective functioning. A too large capacity means loss of energy and a longer waiting time for hot water by the consumer, while a too little capacity will generate energy loss from friction and excessive consumption by pumps.
Norwegian experts have exemplified the details of a proper sizing of the components of various types of biomass heating systems, location of the boiler, advantages of the centralized heating system and its design, as well as relevant European standards.