Implementation of CCPP for energy supply of future building stock

Abstract

and Process Engineering, Kolbjørn Hejes vei 1d, NO-7491 Trondheim, Norway h i g h l i g h t sSensitivity analysis was performed under changeable heat demand profiles. Results found high dependency of plant performance from heat load in DH system. CCPP as the most energy efficient conversion plant is suitable for heat supply of high heat density areas. CCPP operate with difficulties in energy supply of low heat density areas. The power production in CCPP is not influenced by the supply temperature control. a b s t r a c tEuropean Directive 2010/31/EU stated that by the end of 2020 all new buildings should be nearly Zero-Energy Buildings (nZEB). Since such buildings require a low quantity of energy for heating, they can utilize energy from the return line of a District Heating (DH) system. Further, this new type of buildings can successfully be integrated into the fourth generation of heat distribution technology, which is the new trend in the DH industry. On the other hand, existing building stock has a service lifetime of around 50 years, indicating that the required supply temperature in the DH system cannot be lowered beneath a certain level. Hereafter, together with new types of buildings and different policies, this could lead to changes in heat demand profiles of the DH system.The above-mentioned situation in the building market will lead to changes in heat load profiles and unavoidably influence the performance indicators of energy conversion units. Therefore, the focus in this paper was devoted to operation analysis of ethanol-based a Combined Heat and Power (CHP) plant with combined cycle technology under changeable demand conditions and different temperature levels in the DH system.In this paper different temperature levels of the DH system together with two temperature control strategies were considered. Further, the analysis included different heat demand profiles. The analysis was performed in Aspen HYSYS simulation software and data post processing was made by MATLAB. The results found that effective plant operation is highly dependent on heat load profile. Temperature control strategies did not induce a significant change in overall power production in CHP. The decrease in the supply temperature did not show a significant impact on plant performance. However, increase in temperature difference between supply and return lines led to higher power production and better overall plant performance. Further, it was concluded that it is rather difficult to operate CCPP connected to low energy building stock. This means that the CCPP is suitable for high-density heat areas, while it has poor energy performance indicators in low heat density areas.

Dynamic modelling of local low-temperature heating grids: A case study for Norway

“…This lead to a high peak heating demand with respect to the average demand, and lowered the effect of peak shaving. The utilization time for the year was 2206 h, and the load factor was 0.25, which is considered to be low [22]. To obtain a bigger impact, another peak shaving approach, or simply a lower threshold for the peak shaving, could be applied.…”

Endoreversible Trigeneration Cycle Design Based on Finite Physical Dimensions Thermodynamics

“…The restrictive design conditions are included in Table 1. The dimensionless thermal conductance g H and g R were defined through Equations (9) and (19) by imposing engine energy efficiency and refrigeration COP. The numerical results are presented in Table 2 and Figures 3-21.…”

“…Separately, many specific researches regarding new energy systems have been developed. For instance, the most suitable control strategy for certain cogeneration system by referring to the related standards available [2]; comparative analysis of different performance indices, applied to a real small-scale district heating network in operation [3]; exergy destruction rate in each component of Brayton cogeneration systems [4]; analysis based on marginal cost assessment of the internal flows and final products of the system, allowing to explain the optimal operation of the system and the role of the thermal energy storage (TES) in achieving the optimal solution [5]; primary energy savings analysis and exergy destruction analysis to compare decentralized power production through cogeneration/trigeneration systems and centralized thermal plants [6]; investigation of CCHP systems to exhibit the influence of various operating parameters on performance, CO 2 emissions reduction, and exergy destruction in three modes of operation followed by optimization [7]; analysis of specific CCHP hybrid systems composed of a gas turbine, an organic Rankine cycle (ORC) cycle and an absorption refrigeration cycle, for residential usage [8]; ecological coefficient of performance, exergetic performance coefficient, and maximum available work of an irreversible Carnot power cycle [9]; an innovative trigeneration system which uses low temperature level heat sources [10]; development of an exergoeconomic optimization model to integrate solar energy into trigeneration systems producing electricity, heating, and cooling according to exergetic, economic, and environmental targets [11]; exergoeconomic optimization of a trigeneration system using total revenue requirement (TRR) and the cost of the total system product as objective function in optimization using a genetic algorithm technique [12]; a new objective function, representing total cost rate of the system product, including cost rate of each equipment and cost rate of environmental impact (NOx and CO), and minimizing the objective function using evolutionary genetic algorithm [13], an extensive overview of various energy-and exergy-based efficiencies used in the analysis of power cycles [14]; production and use of alternative fuels [15]; integrated heating and cooling with long-term heat storage [16]; residual energy recovery by using small engines such as Stirling [17]; optimization of heating systems based on geothermal heat pumps [18]; implementation of combined cycle power plant (CCPP for energy supply of future building stock [19]; and measures to adapt institutional and financial barriers that restrict the use of cogeneration and district heating networks in the EU-28…”

Energy planning of district heating for future building stock based on renewable energies and increasing supply flexibility

“…The appropriate sizing of production plants is vital to achieve good levels of utilization, to ensure suitable performance for chosen systems, and to enable effective integration with existing or new DH systems [12]. Further, it should be noticed that in most cases the plant operation becomes inefficient if the energy production unit operates under a low plant load [11,13]. Given the high costs of installation and the tight energy saving 6 constraints at which these plants are subjected, an incorrect predictive analysis can result in investment unsustainability either in economic or environmental terms [14,15].…”

“…Further, the energy efficiency of energy production units is treated as constant regardless of the load change. As mentioned before, the energy production unit operates inefficiently under a low plant load [11,13].…”