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Discussion on the renovation of heating sources in universities

Discussion on the renovation of heating sources in universities
In recent years, with the continuous expansion of enrollment in universities, the scale of schools has been increasing year by year, which has brought certain difficulties to the planning and renovation of heating systems. The expansion of heating in many universities cannot keep up with the needs of school development. Due to years of reconstruction and expansion, the heating system cannot form a sustainable development model. Some schools undergo changes every year. Although a large amount of funds have been invested, they have not achieved good heating effects. This is because the renovation plan has not been rigorously demonstrated and the scope involved is incomplete. Firstly, it is the problem of heat source renovation. Therefore, this article will propose the existing problems from the direction of heat source renovation and provide a scientific and rigorous heating renovation plan.
1、 Boiler capacity and number issues.
Due to the continuous increase in school building area, many schools have boiler rooms that have just been expanded and put into operation, but are also facing expansion and renovation. This small capacity boiler not only increases the area of the boiler room and the amount of civil engineering, but also has many problems, such as low boiler operating efficiency, a large number of auxiliary machines, high energy consumption, and large maintenance capacity.
The selection of single boiler capacity should try to choose large capacity units.
Firstly, in terms of boiler heat loss, the boiler capacity has doubled, but there has been no corresponding doubling on the surface, and the heat dissipation has not doubled. The larger the capacity, the higher the efficiency (within a certain range);
Secondly, as the boiler capacity increases, the furnace volume and heating surface also increase accordingly, and the air consumption per unit fuel combustion does not increase, thereby reducing smoke exhaust losses;
Thirdly, in industry design standards, the exhaust gas temperature of small boilers is much higher than that of large capacity boilers. This is because in order to reduce the exhaust gas temperature of small capacity boilers, it is necessary to increase the heating surface of the boiler, thereby increasing the steel consumption of the boiler. The increase in volume results in poor economic efficiency. Due to the significant difference in exhaust gas temperature, the difference in exhaust gas losses between the two is further increased.
There are many other factors that can affect the difference in thermal efficiency between the two. Therefore, when selecting boiler capacity, it is advisable to choose a large capacity boiler and fully consider meeting the needs of staged load adjustment.
In addition, according to the school's medium and long-term development plan and the current number of boilers. In terms of operating life, the boiler capacity should be retained in the overall planning of the boiler room, but it is not recommended to retain too many positions. Firstly, the amount of civil engineering work is too large, and secondly, due to the uncertainty of future school development, it will lead to long-term idle and waste. It is recommended to retain positions.
2、 The disadvantages of parallel operation of boilers with different parameters.
Due to the phased increase of boilers in many schools, the temperature parameters of the supply and return water of boilers installed at different periods are different, resulting in a large difference in boiler supply and return water temperature. If the circulating water of the boiler is too large, it not only deviates from the internal water distribution of the boiler, but also affects the internal water circulation of the boiler. Large temperature difference boilers increase system resistance loss, which has a certain impact on the normal operation of the entire system. Therefore, in the renovation of boiler rooms, parallel operation of boilers with different supply and return water temperature differences is not advocated.
If necessary, it is recommended to take the following measures to alleviate its impact: if the boilers are arranged in parallel, the boilers with large temperature differences should be placed near the circulating pumps, and the indirect side of the boiler supply and return water main pipe should be used to achieve direct circulation of system circulating water through the bypass pipe instead of the boiler. The bypass pipe diameter should be selected according to the system and boiler resistance, and should not be too large. In principle, the following types should be met: S total=S1+S2+S3+bypass;
Data: S total: total resistance loss between boiler supply and return water main pipes;
S1.S2.S3: Resistance losses of each of the three boilers;
S bypass: Resistance loss of bypass pipe
It should be noted that the resistance loss of the renovated boiler should be close to the original design value.