Reduction of Heat Losses Using Quadruple Heating Pre-Insulated Networks: A Case Study

Abstract

The paper presents an analysis of heat loss and reductions of annual emissions of air pollutants of a quadruple pre-insulated heating network by comparing this solution with the existing pre-insulated network consisting of four pre-insulated single pipes and the variant consisting of two twin pipe pre-insulated. For calculations, an existing heating network located in central Poland was adopted, where heat is transported for heating purposes of buildings and domestic hot water with circulation of domestic hot water through four separate pre-insulated underground pipes. The idea of the construction of four pre-insulated pipes presented in the paper consists in the location of four steel pipes in a common round thermal insulation, which perform the role of heat transport for heating purposes in multi-family buildings (supply and return) and two pipes transporting hot water (a pipe with domestic hot water with circulation). In Poland, heating pipes used in multi-family housing have a larger diameter compared to domestic hot water pipes, which is why standard twin pipe heating pipes have been used in the construction of four pre-insulated networks, in which the domestic hot water pipe has been added to the thermal insulation and circulation of domestic hot water. In order to determine heat losses, a simplified two-dimensional model of conductive heat transfer was developed using Fortran to create a computer program. The results of numerical simulations show that the use of twin pipes for the construction of pre-insulated quadruple networks has contributed to a significant reduction in heat loss in relation to the existing single pre-insulated network (up to 57.1%), while reducing the thermal insulation field of the cross-section of the pre-insulated pipe by 21.4%.

Method for Assessing Heat Loss in A District Heating Network with A Focus on the State of Insulation and Actual Demand for Useful Energy

“…ZuluThermo© also offers a user-friendly interface that may come in handy for taking wear rates into account and interacting with external software. Meanwhile, Teleszewski et al [39] developed another kind of model in which the DHW pipes have been added to the common with the supply and return pipes round thermal insulation, and to determine heat losses, a simplified two-dimensional model of conductive heat transfer was created.…”

Experimental Assessment of the Thermal Conductivity of Basalt Fibres at High Temperatures

“…Based on the results of the work performed, an original layout was proposed, combining several pipelines. In [9], this topic was developed further and a variant of the layout of a heat network with four pipes in one pre-insulated casing (two pipes for heating and hot water supply) was discussed. The authors claimed that such pre-insulated pipes significantly reduce heat loss, increase the environmental friendliness of the coolant transportation compared to four single pre-insulated pipes while reducing the cross-sectional area of the thermal insulation.…”

Testing heat supply networks for heat losses

“…The target of the tests is to determine the heat losses for various types of routing and design of the pipeline insulation that are specific to the heat network in question. Based on the test results, the insulation condition of the tested pipelines under the specific routing operating conditions is assessed [1][2][3][4]. The tests were performed for the network sections with the routing type and the insulation design is the characteristic of the given network, which facilitates expansion of the test results to the heating network as a whole [5][6][7][8][9].…”