Heat Supply Network Research Articles

Hydraulic modeling and experimental study of three heat sources and three rings heating networks

For the further research on the hydraulic characteristics of multi-source and multi-ring heating network polycyclic, this paper based on the fluid network analysis, the hydraulic intersection user virtual segmentation, at the ends of common pipe set virtual users or virtual heat source modeling method, the hydraulic simulation model of three heat sources and three rings of a heating pipe network is established by using MATLAB platform. Based on the experimental platform of the multi-source heat supply network, the three heat sources and rings ideal working conditions and the variation of the two working conditions are simulated and experimentally studied. The results show that under the 3 different conditions, the maximum absolute value of relative error of simulation data and the experimental data were 1.30%, 1.26% and 1.09%, to verify the validity of the simulation method proposed in this paper and the simulation model and the accuracy of.

Electricity consumption and economic analyses of district heating system with distributed variable speed pumps

The increasing of energy efficiency and decreasing the transportation power consumption of District Heating (DH) systems have been increasingly focused due to the need to save energy. In this paper a new district heating network with distributed variable-frequency speed pumps (DVFSP) is presented and analyzed. The approach for minimum of the capital costs and energy consumption in a district heating network is presented using a case study based on a district heating network with DVFSP in Dalian, China. The computational tool is a commercial software package, which is used to design and analyze DH networks. Increasing temperature difference between supply and return pipes, the annual total electricity consumption and the equivalent annual cost are reduced. The energy efficiency in the DH system with the DVFSP was compared with the one in the DH system with conventional central circulating pump (CCCP). Analysis results show that the average electrical energy saved by the DH system with the DVFSP is 49.41% of the one saved by the DH system with conventional central circulating pump. The average pumps power consumption of heating area per square meter in primary heat supply network is 0.325kWh/m2.

无热网背压机组试运方法的研究

背压发电供热机组热效率高，近年来逐步为中小城市热电联产所青睐。而供热机组在建设过程中普遍存在热网建设滞后于机组建设的问题。对于背压机组来说，无热网对机组试运带来了更多的难题。本文从无热网对于机组试运带来的影响入手，分析了机组无热网所产生的一系列问题，提出了合理的试运方案。该课题的研究成果对于同类型机组的试运具有借鉴意义。 The back pressure turbine has high thermal efficiency, and it has been popular in recent years in small and medium-sized city cogeneration. But the heat supply network construction always lags behind the unit construction. To the back pressure turbine, it has some troubles on trial operation of the unit. In this paper, the study began with the effects of no heat supply network to the back pressure turbine, and analyzed a series of problems produced. Finally some reasonable trial op-eration schemes have been proposed to solve these problems. The research result has reference significance to the trial operation of the same type of unit.

Hydraulic Condition Analysis of Different Position Heat Exchange Stations in Heat Supply Network

Through the establishment of Yuhua ring-shaped heat supply network model, the paper analyses the influence on hydraulic condition and the heat source’s flow change when heat exchange station at different locations closed. Final results show that the nearer heat users distance the closed heat exchange station, the bigger change in hydraulic condition; When the farther heat exchange station closed, it has more influence than the nearer one on the whole network’s hydraulic condition, but it has little influence on the heat source’s flow change.

The Research of Absorption Heat Pump Taking Basic Heat Load City Heat-Supply Network Heating Regulation Optimization

This paper aiming at absorption heat pump maximizing annual heating quantity, with the goal of thermal power plant absorption heat pump heating earnings in different heating regulation mode, set up calculation model of absorption heat pump heating earnings, analysis heat-supply network backwater temperature fluctuations and heat pump heating quantity difference in different heating regulation mode, discuss optimization approach of absorption heat pump taking basic heat load city heat-supply network heating regulation, calculate heat pump heating earnings finally. The results showed that the pure quality regulation can get the best economic benefits of absorption heat pump.

Stress Corrosion Cracking of Stainless Steel Expansion Joint for Heat-Supply Network

Tree-like transgranular cracks were found at the bottom of a expansion joint bellow that had been used for heat-supply network at 90°C and 0.8MPa. A failure analysis was conducted, including visual, microstructural, compositional, and mechanical characterization, to determine the cause and source of the degradation. Branched, brittle cracks were observed in the failure region and exhibited transgranular propagation. The results showed that the concentration of the chloride in the deposit was 248 ppm in the intermittent wet/dry cycles situation. It was determined that the likely cause of failure was neutral pH, Concentrated chloride-induced stress corrosion cracking.

Research on the Capacity of In-Depth Peak Regulation of Large-Scale Heat Supply Unit Based on Characteristics of Thermal Storage of Heat Supply Network and Buildings

Against the backdrop that wind power is always abandoned in heat supply period in winter after wind power is taken into power grid in northern areas of China and there exists a big proportion of large-scale heat supply units in power grid, a method for in-depth peak regulation of large-scale heat supply unit based on characteristics of thermal storage of heat supply network and buildings is put forward in this paper, and a mathematical model for in-depth peak regulation is established. The calculation in a case indicates that the change of heat production of large-scale heat supply unit will not affect the quality of heat supply to a certain extent. During heat supply period, thermal load of heat supply network shall be moderately lowered to coordinate with the in-depth peak regulation when power grid is at its low ebb, and heat supply shall be moderately decreased based on characteristics of thermal storage of heat supply network and buildings when the peak regulation capacity of power grid is very limited, which indicates that it is feasible and practical to help power grid go through its low ebb with the peak regulation capacity gained here. Through the mathematical model established in this paper, time of thermal storage and thermal release as well as such units capacity of in-depth peak regulation can be calculated, which provides a scientific basis for dispatcher of power grid to conduct in-depth peak regulation of heat supply unit.

1023 電力および熱の面的利用を行う地域の規模による環境性および経済性への影響(GS-8 エネルギーシステム)

1023 電力および熱の面的利用を行う地域の規模による環境性および経済性への影響(GS-8 エネルギーシステム)

Research and Realization of Remote Monitoring System for Central Heating

In view of the central heating problems for remote, a realization scheme of remote monitoring system for central heating is presented. In this paper, the composition and functions of the heat supply network monitoring center, the heating station monitoring and control system and the wireless communication system are introduced, the control system hardware configuration is discussed. The system has already been used and run in a good effect.

Improvement of a method of estimating the heat and mass transfer of the linear part of the pipeline network based on its static functioning mode

A modified quasi-one-dimensional model of mass transfer is proposed, by means of which one can accurately predict the functioning parameters of the water heat-supply pipeline network.

Study of Economic Specific Frictional Resistance in Hot Water Heat Supply Net Work in Xi’an

Based on technical and economic analysis,apply optimal theory to explore the optimal values of economic specific frictional resistance and put form and a sound theory formula .Apply the formula to the real project and calculate the values of the economic is specific frictional resistance optional pipe diameter and velocity on different heating-supply scale under current prices.

Research on Modeling Method of Thermodynamic Verifying Calculation for Heat-Supply Network

This paper establishes a model of thermal checking calculation of heat supply network based on graph theory and thermodynamic calculation, by analyzing directly buried installation of thermal network utilizing the heat-transfer mechanism and principle of thermal equilibrium. Take the directly buried heat supply network for instance, in which hot water is as a heat medium. The establishment of the spatial database and attribute database of thermal network based on GIS and Microsoft Access respectively, as well as the thermodynamic calculation of thermal networks based on GIS developed by object oriented programming language VB is done .Thus enables point-and-click query, update on property and thermal calculation functions. Finally, through comparative study on the calculation results and actual operation of the system, we find the relative error of the thermodynamic temperature is less than 10%.

Analysis and Controlling Method of Pump Vaporization in Heat Supply Network

The cavitation in pump is an important factor impacts the operating safety of the pump, and against the cavitation occurrence, this paper chooses the SM253-640 centrifugal water pump as the study object to analysis the reason and the harm caused by cavitation. And this paper showed how to line-pump cavitation, especially, while the flow rate of the medium is very small and the temperature is high. The safety operating interval of the pump was analyzed in this paper, and showed how to avoid the pump cavitation and improve the pump working efficiency, to ensure the safety and economic operation of the heat supply network.Introduction

Estimating the efficiency of the vacuum deaerators used for treating network water at the Samara cogeneration station and their modernization

Results from experimental studies on analyzing the operating conditions of the vacuum deaerators used to treat makeup water for the heat supply network connected to the Samara cogeneration station are presented. Proposals for improving the design of the DB-800 deaerator No. 5 at the Samara cogeneration station were worked out, its retrofitting was completed, and thermal tests were carried out.

The effect of oxygen concentration on the corrosion of heat supply networks and heat exchangers

Data on the rates of general corrosion and pitting corrosion for carbon steel and brass that were obtained during bench tests and at industrial facilities as a function of the concentration of oxygen in the heat supply network are considered.

Reliability and quality of heat supply as priorities of SNiP (Construction Code and Regulations) 41-02-2003: Heat supply networks

The difference between the new Construction Code and Regulations and the SNiP (Construction Code and Regulations) 2.04.07-86*: Heat Supply Networks is shown. The set of new codes for the design of heat supply networks is presented, and the regulations are pointed out deviating from which may inflict damage to the health and safety of population, and to the environment. Criteria of heat-supply network reliability are considered in detail.