Spatial and Time Distributions of Energy Consumption of High Back Pressure District Heating by Combined Heat and Power Generation

2021 ◽  
Author(s):  
Yichen Zhang ◽  
Zhihua Ge ◽  
Xiaoze Du
Energies ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 2487 ◽  
Author(s):  
Heng Chen ◽  
Zhen Qi ◽  
Qiao Chen ◽  
Yunyun Wu ◽  
Gang Xu ◽  
...  

A conceptual high-back pressure (HBP) heating system cooperating raw coal pre-drying for combined heat and power (CHP) was proposed to improve the performance of the HBP-CHP unit. In the new design, besides of heating the supply-water of the heating network, a portion of the exhaust steam from the turbine is employed to desiccate the raw coal prior to the coal pulverizer, which further recovers the waste heat of the exhaust steam and contributes to raising the overall efficiency of the unit. Thermodynamic and economic analyzes were conducted based on a typical 300 MW coal-fired HBP-CHP unit with the application of the modified configuration. The results showed that the power generation thermal efficiency promotion of the unit reaches 1.7% (absolute value) owing to suggested retrofitting, and meanwhile, the power generation standard coal consumption rate is diminished by 5.8 g/kWh. Due to the raw coal pre-drying, the energy loss of the exhaust flue gas of the boiler is reduced by 19.1% and the boiler efficiency increases from 92.7% to 95.4%. The impacts of the water content of the dried coal and the unit heating capacity on the energy-saving effect of the new concept were also examined.


1997 ◽  
Vol 45 (1) ◽  
pp. 97-107
Author(s):  
H.F. De Zwart ◽  
G.P.A. Bot

This paper studies the prospects for the use of reject heat from on-site combined heat and power generation in horticulture. In particular, the consequences of CO2-dosing with exhaust gases is studied. All computations are made with a recently developed dynamic simulation model describing the energy consumption of a greenhouse and the performance of its heating system as a function of outside weather conditions and horticultural requests of growers in the Netherlands.


2000 ◽  
Author(s):  
Jeppe Grue ◽  
Jens Andersen ◽  
Niels From ◽  
Inger Bach

Abstract In Denmark power generation is extensively based on small combined heat and power plants, which produce electric power and district heating. This work will focus on the small plants around 1 MW in size, which are often unmanned and operating completely automatically. The objective of this work is to formulate a method which can be used to determine the optimal operating strategy for a CHP plant, and that this strategy must be fully automated. The contribution margin of the plant is used as the objective function for the optimization. Finally the method is tested on a small CHP plant, which is a gas engine producing 1.34 MW electrical power and 1.6 MJ/s district heating. The methods, which are developed, can be used in general for the evaluation and optimization of automated strategies for the operation of small-unmanned CHP plants. The strong feature of the method is that it sets an ultimate target that is the best possible one to obtain with a view to any strategy. This provides a basis for the evaluation and optimization of the actual strategy.


2021 ◽  
Vol 13 (8) ◽  
pp. 4527
Author(s):  
Daniele Fiaschi ◽  
Giampaolo Manfrida ◽  
Barbara Mendecka ◽  
Lorenzo Tosti ◽  
Maria Laura Parisi

In this paper, we assess using two alternative allocation schemes, namely exergy and primary energy saving (PES) to compare products generated in different combined heat and power (CHP) geothermal systems. In particular, the adequacy and feasibility of the schemes recommended for allocation are demonstrated by their application to three relevant and significantly different case studies of geothermal CHPs, i.e., (1) Chiusdino in Italy, (2) Altheim in Austria, and (3) Hellisheidi in Iceland. The results showed that, given the generally low temperature level of the cogenerated heat (80–100 °C, usually exploited in district heating), the use of exergy allocation largely marginalizes the importance of the heat byproduct, thus, becoming almost equivalent to electricity for the Chiusdino and Hellisheidi power plants. Therefore, the PES scheme is found to be the more appropriate allocation scheme. Additionally, the exergy scheme is mandatory for allocating power plants’ environmental impacts at a component level in CHP systems. The main drawback of the PES scheme is its country dependency due to the different fuels used, but reasonable and representative values can be achieved based on average EU heat and power generation efficiencies.


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