1 Overview
Heating is a major infrastructure for modern cities. Scientifically and rationally planning special heating projects in urban central areas is an important way to save energy and protect the environment. In order to develop cogeneration and promote urban central heating, in order to save energy, protect the environment, control pollution, improve people's quality of life and implement sustainable development strategies, relevant state departments have also promulgated a series of policies, regulations and regulations. Wait. In 1995, the "Notice on Strengthening the Management of Urban Heating Planning" [1] pointed out: "Developing scientific heating planning and organizing implementation according to planning is an effective means to avoid blind construction and redundant construction." And the paper issued the "Technical Requirements for Urban Heating Planning" and "The Depth of Urban Heating Planning Content", the general principles of heating planning, heat load determination, heat source and heating mode, heat network, cost and benefit analysis Principles and guidance have been made [2]. At present, the introduction of the new urban planning law and the renewable energy law has put forward higher requirements for the preparation of heating plans, and has increased the difficulty and complexity of the preparation.
In the planning and preparation process, the central district heating planning of a city strives to fully implement the scientific development concept, adhere to the people-oriented principle, and promote the development of energy, environment and economy, combine development with energy conservation and environmental protection, and overall planning to ensure heating. The cause is sustainable. This plan is based on the overall urban planning of a prefecture-level city from 2006 to 2020, and is linked with other related plans. It proposes the guiding ideology, principles and development goals of heating development, and determines the planning plan for the development of heating business. , key work and safeguards. Scientific and rational planning of heat supply construction and development is of great significance for improving heating capacity, meeting people's living needs, improving the atmospheric environment, and building a harmonious society. The heating system is mainly composed of three parts: heat source, heat network and heat user. This paper will study the preparation of heating special plan from these three aspects.
2 heat load is a dynamic development process, to make scientific predictions
The heating area is the basic data for the development of heating planning [3], which is derived from the land use planning in the overall planning or detailed planning. When determining and calculating the heat load, the heating area should be carefully studied and strive to be detailed and accurate. In the heating planning, the total building area is used as the control base, and the heating area and heat load of each area are predicted according to the floor area ratio, the heating rate and the heat index. Since the heat load is dynamically developed and there is a gradual process, it is necessary to predict the heat load in stages to guide the staged construction of the heat network.
The heat load forecast mainly has the following problems:
(1) The current heating gap is large, and the recent heat load has increased significantly.
(2) Due to the construction and development of the central city and the expansion of the overall development of the city, the urban heat load will increase significantly in the long-term planning.
(3) When there is industrial heat load demand in the central city, the industrial development of the central city should be fully considered.
(4) Due to the newly increased residential area in the urban area, there is a phenomenon that the residential area has been completed, but the occupancy rate is difficult to predict.
The main solutions are as follows:
(1) Building energy consumption accounts for about one-third of the total energy consumption. Saving building energy consumption is of great significance for building a conservation-oriented society. The state has also formulated a series of measures for this, in the process of preparing special heating plans. The heat load forecast should be carried out in strict accordance with the latest energy-saving standards of the country.
(2) It is necessary not only to predict the total amount of heat load, but also to closely combine the latest construction of the city to perform segmentation and block prediction statistics.
(3) Due to the large number of industrial enterprises in the urban area and the large amount of gas used, it is necessary to combine the enterprise's own development plan, investigate the heat load carefully, and divide the statistics into sections to facilitate the planning of heat sources near the industrial park.
(4) The newly-added residential quarters in the urban area shall be forecasted and calculated in strict accordance with the relevant data of the planning department. The recent and long-term statistics shall be separately provided to provide a scientific data foundation for the construction of relevant supporting municipal facilities.
3 heat source planning should be based on cogeneration
The heat source is the core of urban heating. Urban heating has two types of dispersion and central heating [4]. Centralized heating is mainly based on central heating, due to its large heat source capacity, high thermal efficiency, low fuel consumption per unit, labor saving and small floor space. The more commonly used heat sources are cogeneration and regional boiler houses. Cogeneration has the comprehensive benefits of saving energy, improving the environment, improving the quality of heating, and increasing the supply of electricity. At present, with the adjustment of national industrial policies, the implementation of environmental protection policies and the gradual implementation of new policies for the development of cogeneration, it is important to develop large-scale heat sources based on cogeneration. Therefore, central district heating needs to develop large-scale central heating heat sources in line with national industrial policies, environmental protection policies, and approval approvals [5].
In the process of preparation, the planning and heat source enterprise's own development planning should be well combined, combined with the company's own innovative energy-saving technology, actively promote advanced centralized heating technology, make full use of the waste heat of the thermal power plant for heating, development should be Thermal power generation, cogeneration of heat and power, to achieve heating network, unified management, and improve the comprehensive utilization of energy.
The heat source planning mainly has the following problems:
(1) Due to the lack of heat sources in the current situation, there are some small coal-fired boilers in the urban area. When the heating season comes, small boilers pollute the urban environment.
(2) At present, the energy structure is still dominated by traditional energy sources, and new energy and renewable energy sources are used less. Moreover, the heating mode is still dominated by the traditional mode, and the new heating mode is less.
(3) Part of the residual heat generated during the cogeneration process needs to be used reasonably, effectively and scientifically.
(4) Due to the imbalance of the heat source development area, the heat source in some areas is insufficient, there is a heating gap, and heat sources in other areas are needed to supplement it.
The main solutions are as follows:
(1) With the cogeneration heat source as the main heating method, some small coal-fired boilers will be gradually removed. Encourage the diversification of heating methods and adopt a new type of heating method with a certain proportion of heat load.
(2) According to the distribution of heat load in each region and the distribution of existing heat sources, combined with the current heating pipe network, plan the peak peaking boiler room and heat exchange station, and uniformly use the heat source.
(3) Using the waste heat of the thermal power plant to heat the low-temperature circulating water in the vicinity of the power plant to replace the original heating pipeline in the area and save energy.
(4) In order to meet the demand for heat load in the long-term city, it is necessary to build a large-scale thermoelectric unit according to the latest national cogeneration policy and the national national policy of saving land, saving energy, and protecting the environment. Hot large main heat source.
4The development of thermal network planning should be effective with the existing hot network resources
The central urban area is a region with a concentrated heat load, and there is a large demand for civil heating load in the region, which is related to the safety and stability of the people's winter heating, and is related to the stability and harmony of the society. The central urban area is an area where the development of central heating is relatively early. Not only part of the pipe network has been aging, but also the heat load has increased year by year, facing the problem of the renovation of the new heat network and the existing heat network.
The hot network planning mainly has the following four problems:
(1) In places where urban construction and development are more mature, various pipelines are dense and the line is tight. If you want to expand capacity during the transformation, it is difficult to find new line positions.
(2) If you want to transform a steam pipeline with a large heat loss into a relatively high-efficiency high-temperature water pipeline, it will be related to the renewal of the relevant auxiliary facilities such as the original heat exchange station, and the investment in the project will increase.
(3) The reconstruction time of the heating network can only be between the two heating periods, and the transformation practice is limited.
(4) If there is steam demand in some areas where hot water is used as the heat medium, it is difficult to satisfy.
The main solution is the following four points:
(1) The laying of the heating pipe network can be combined with the relevant road reconstruction project for unified planning.
(2) The hot spot network in the area where the line is tight will continue to use the steam as the heat medium, which can make full use of the existing heat network resources.
(3) It can replace the original steam as a heat medium in the hot spot with hot water as the heat medium in the conditional area, saving steam usage.
(4) According to the development of near-and long-term thermal load in urban areas, multi-heat source network supply can improve the thermal energy utilization rate and heating reserve capacity of the entire heating system to ensure reliable heating load and industrial heat load supply in winter. Sex, safety.
5 summary
With the economic growth and the rapid development of the city, the development of urban heating has accelerated. In the preparation of heating planning, it is necessary to integrate the original heating resources, optimize the urban heating structure, transform the heating development mode, improve the existing facilities, and seek a path of scientific development. This paper summarizes the compilation experience of a special heating project in a downtown area, and combines other relevant materials to discuss the following new problems in the current heating planning, and proposes solutions to make the heating special planning more Guide the construction of urban heating projects well.
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