Integrated multiscale simulation of combined heat and power based district heating system

A Proton Exchange Membrane Fuel Cell Combined Heat and Power system (PEMFC-CHP) fuelled by the hydrogen-rich gas reformed from biogas may be seen as an efficient and sustainable technology. This system can provide electrical and thermal energy dynamically to residential applications. In this study, an assessment of the economic performance of an integrated biogas plant and PEMFC-CHP for Swedish electricity and heat prices is presented. The economic factors considered are the capital and operation & maintenance (O&M) costs of the biogas plant and the PEMFC-CHP, the price of heat and electricity, and the value of the digestate as fertilizer. The analysis includes two cases: 1) both biogas plant and PEMFC-CHP are located on the farm. The farm sells the electricity and heat to the power grid and district heating system, respectively; 2) the PEMFC-CHP is located in a centralized-biogas plant, not on the farm. The manure is transported from farms to the plant. The plant also sells the electricity and heat to the power grid and district heating system. The results show that the farm-based and the centralized biogas plant have almost the same biogas production cost. The electricity cost of today, expected for 2020, and for the break-even of this integrated system are 530, 305 and 197 €/MWh, respectively. With the current trend of the fuel cell industry development, this break-even price may be reached in the near future.

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Analysis of the Impact of Decreasing District Heating Supply Temperature on Combined Heat and Power Plant Operation

Environmental and Climate Technologies ◽

10.1515/rtuect-2014-0013 ◽

2014 ◽

Vol 14 (1) ◽

pp. 41-46 ◽

Cited By ~ 13

Author(s):

Alona Bolonina ◽

Genadijs Bolonins ◽

Dagnija Blumberga

Keyword(s):

Power Plant ◽

District Heating ◽

Heating System ◽

Combined Heat And Power ◽

District Heating System ◽

Heating Systems ◽

Plant Operation ◽

Operation Modes ◽

Power Plant Operation ◽

The Impact

Abstract District heating systems are widely used to supply heat to different groups of heat consumers. The district heating system offers great opportunities for combined heat and power production. In this paper decreasing district heating supply temperature is analysed in the context of combined heat and power plant operation. A mathematical model of a CHP plant is developed using both empirical and theoretical equations. The model is used for analysis of modified CHP plant operation modes with reduced district heating supply temperature. Conclusions on the benefits of new operation modes are introduced.

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Exergoeconomic Analysis of New High-Temperature District Heating System Based on Absorption Heat Pump Technology in Combined Heat and Power

Volume 5: Energy Systems Analysis, Thermodynamics and Sustainability; NanoEngineering for Energy; Engineering to Address Climate Change, Parts A and B ◽

10.1115/imece2010-38014 ◽

2010 ◽

Author(s):

Fangtian Sun ◽

Lin Fu ◽

Shigang Zhang

Keyword(s):

Heat Exchanger ◽

Heat Pump ◽

Waste Heat ◽

District Heating ◽

Heating System ◽

Combined Heat And Power ◽

Space Heating ◽

Exergetic Efficiency ◽

District Heating System ◽

Absorption Heat Pump

Space heating area of district heating system of combined heat and power (CHP) accounts for approximately one third of total space heating area in Chinese northern cities. In the extraction condensing turbine combined heat and power system based on district heating network, there are a large number of low-grade waste heat in the condenser, and exergy loss in the steam-water heat exchanger and water-water heat exchanger. Based on absorption heat pump technology, a new high-temperature district heating technology (DHSAHP) was presented to improve the current district heating system of CHP. Absorption heat pumps are used to recycle low-temperature waste heat in condenser. Absorption heat pump type heat exchanger is used to reduce temperature of return water in primary heat network, and decrease irreversible loss. Where, DHSAHP was analyzed by thermodynamics and economics method, and evaluated by exergetic efficiency, exergetic output cost, exergetic cost difference and exergoeconomic factor. Compared with current district heating system of CHP, DHSAHP can decrease about 31.3% steam consumption, increase about 75% transmission and distribution capacity of the primary heating network. The evaluation results show that the exergetic efficiency of new district heating system of CHP based on the absorption cycle technology is higher 10.41% than that of current district heating system of CHP, whereas its exergetic cost is lower 36.6¥/GJ than that of the conventional district heating system. With the increase of annual heating time, economy efficiency of new district heating system of CHP becomes better. The DHSAHP has higher energy utilization efficiency and better economic benefits and provides a kind of better technological method to solve the main problems of cuurent district heating with CHP in China.

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