The One-Pipe Centralized Heating System And Comparison Analysis

With the development of the city planning and constructing, the kinds of the underground pipe increase gradually and the distribution expands quickly, however, the available space of the pipes is limited. At the same time, under the vigorous sustainment of the government, with the gradual increasing of people's living standard and the quickness of town construction, centralized heating that advances rapidly in recent years has become the main mode of production and living heat. However, with the penetration of the market economy, owing to the influence of history and energy as well as environment, the development of centralized heating system falls across some resistance.Aimed at the problem that some city districts especially some old city districts can't realize centralized heating because of large occupying area and the difficulty in laying of the supply and return pipes of the heating networks, in order to popularize the joint operation of heat-supply networks of many heat sources and distributing variable-frequency technique along with the direct connection between heat users and heating system by mixing water pump, extend the design temperature range of the non-compensation underground burying laying, solve the abrupt change of the hydraulic condition in household heat metering systems, this paper puts forward the one-pipe centralized heating system, which is a system that heat is transported by the network from heat source to heat users then back to heat source. The main line is not only supply pipe but also return pipe in this system adopting user or branch line distributing variable-frequency pump to realize the normal operation. Furthermore, the cost of the centralized heating system increases with the continuous rising price of raw and processed materials, the one-pipe heating system could alleviate the pressure in fund in some degree. The number of the heat source could be one or more. This paper mainly researches the double heat sources.This paper compares the existing two-pipe heating system with one-pipe heating system from the following points, such as the direct connection by mixing water pump, distributing variable-frequency pump, the joint operation of heat-supply networks of many heat sources , the operation and regulation of household heat metering systems , non-compensation underground burying laying, the adaptability to extension network, some advantages are found through the comparison, and some problems could be solved in practice. Besides, design principles and design processes are given. Finally, this paper points out the design calculation method of the one-pipe heating system through a design example.No literature is yet available either here or abroad that researches the one-pipe heating system in detail. As a result of the limits of the paper length and time as well as the capability of the author, there are a few unsettled problems which is expected to be solved in the following thesis study.