| Abstrakt: |
The technical condition of thermal networks in many ways determines the quality and the reliability of a heat supply. When replacing worn out networks, thermal networks constructions with monolithic insulation made of polyurethane foam, so-called 'pipe in pipe' (PIP) are used. There are several varieties of PIP pipelines, differing in the pipe material, the connection method, the service life. The article compares three options: the first option - steel pipes in monolithic insulation made of polyurethane foam (PUF) with an outer shell made of rigid polyethylene; the second option - flexible polymer pipes made of cross-linked polyethylene (for example, Isoproflex'); the third option - corrugated pipes made of stainless steel (for example, 'Casaflex'). Researches were carried out on the basis of variant design of thermal networks with various expenditure of the heat carrier for the connected consumers. As a comparative parameter characterizing the material capacity of the compared variants, the reduced area of the longitudinal section is used. Graphs illustrating the dependence of the cost of construction of the thermal network for three compared materials are given. The cost calculations take into account the cost of pipes, fittings and the cost of installation works. As criterion for comparison of options for construction of the thermal network are used the discounted costs, the result of the comparison of which showed that economically feasible is a variant of the thermal network of plastic pipes with insulation of polyurethane foam. |
