Application of heat pump in combined heat and power central heating system and exergy analysis

2019 ◽  
Vol 14 (3) ◽  
pp. e2312
Author(s):  
Zhouming Jiang ◽  
Yajun Li

Author(s):  
Xiao Wang ◽  
Lin Fu ◽  
Xiling Zhao ◽  
Hua Liu

In recent years, with the continuous urban expansion, the central heating sources are commonly insufficient in the areas of Northern China. Besides, the increasing heat transfer temperature difference results in more and more exergy loss between the primary heat network and the secondary heat network. This paper introduces a new central heating system which combines the urban heat network with geothermal energy (CHSCHNGE). In this system, the absorption heat exchange unit, which is composed of an absorption heat pump and a water to water heat exchanger, is as alternative to the conventional water to water heat exchanger at the heat exchange station, and the doing work ability of the primary heat network is utilized to drive the absorption heat pump to extract the shallow geothermal energy. In this way, the heat supply ability of the system will be increased with fewer additional energy consumptions. Since the water after driving the absorption heat pump has high temperature, it can continue to heat the supply water coming from the absorption heat pump. As a result, the water of the primary heat network will be stepped cooled and the exergy loss will be reduced. In this study, the performance of the system is simulated based on the mathematical models of the heat source, the absorption heat exchange unit, the ground heat exchanger and the room. The thermodynamic analyses are performed for three systems and the energy efficiency and exergy efficiency are compared. The results show that (a) the COP of the absorption heat exchange unit is 1.25 and the heating capacity of the system increases by 25%, which can effectively reduce the requirements of central heating sources; (b) the PER of the system increases 14.4% more than that of the conventional co-generation central heating system and 54.1% more than that of the ground source heat pump system; (c) the exergy efficiency of the CHSCHNGE is 17.6% higher than that of the conventional co-generation central heating system and 45.6% higher than that of the ground source heat pump system.



2021 ◽  
Vol 25 (1) ◽  
pp. 130-139
Author(s):  
Е.G. Komarov ◽  
◽  
V.V. Lozovetsky ◽  
V.V. Lebedev ◽  
V.M. Cherkina ◽  
...  

Results of design modeling of air-conditioning and central air of premises of server stations are presented. The estimation of thermal balance of typical server station is made. The potential of thermal energy which can be used is estimated it is useful for needs of central heating, to save power resources, and not to pollute environment thermal emissions. The detailed analysis of components of is material-power balance is made. The mathematical model of central air is developed for these purposes. Analysis problems of the heat substances exchange processes, the drainage of air connected with processes, occurring at its cooling are considered. The designing and operation problems interfaced with the heat substances exchange in air coolers are considered. The heat pump scheme of system is offered the central heating, utilizing warmly server station at air conditioning indoors. The model is offered and results of optimization of parameters heat pump schemes are considered. Results can be applied at designing of central airs of premises of server stations with passing recycling of thermal emissions for needs of central heating.



2020 ◽  
Vol 10 (1) ◽  
pp. 323 ◽  
Author(s):  
Yi Yang ◽  
Zihua Wang ◽  
Qingya Ma ◽  
Yongquan Lai ◽  
Jiangfeng Wang ◽  
...  

In this paper, a novel combined heat and power (CHP) system is proposed in which the waste heat from a supercritical CO2 recompression Brayton cycle (sCO2) is recovered by a LiBr-H2O absorption heat pump (AHP). Thermodynamic and exergoeconomic models are established on the basis of the mass, energy, and cost balance equations. The proposed sCO2/LiBr-H2O AHP system is examined and compared with a stand-alone sCO2 system, a sCO2/DH system (sCO2/direct heating system), and a sCO2/ammonia-water AHP system from the viewpoints of energy, exergy, and exergoeconomics. Parametric studies are performed to reveal the influences of decision variables on the performances of these systems, and the particle swarm optimization (PSO) algorithm is utilized to optimize the system performances. Results show that the sCO2/LiBr-H2O AHP system can obtain an improvement of 13.39% in exergy efficiency and a reduction of 8.66% in total product unit cost compared with the stand-alone sCO2 system. In addition, the sCO2/LiBr-H2O AHP system performs better than sCO2/DH system and sCO2/ammonia-water AHP system do, indicating that the LiBr-H2O AHP is a preferable bottoming cycle for heat production. The detailed parametric analysis, optimization, and comparison results may provide some references in the design and operation of sCO2/AHP system to save energy consumption and provide considerable economic benefits.



Entropy ◽  
2015 ◽  
Vol 17 (4) ◽  
pp. 2328-2340 ◽  
Author(s):  
Xiao Chen ◽  
Xiaoli Hao


2013 ◽  
Vol 313-314 ◽  
pp. 759-762
Author(s):  
Yun Feng Ma ◽  
Yan Xiang Liu ◽  
Tao Ji

In order to fully recycle power plant’s circulatingwater heat, improve the thermal efficiency and protect the environment, thispaper designs the comprehensive scheme of heat pumptechnology recycling power plant’s circulating water heat, including theboiler mae-up water pre-heating system, the central heating circulatingsystem and the domestic hot water circulating system, which not only run at thesame time but also function independently. Even in non-heating seasons,the waste heat of circulating water can be utilized fully. It is worthmentioning that this paper puts forward to install climate compensationdevice in the central heating system, which can perform intelligent district timesharing control to meet different users’ needs.



2013 ◽  
Vol 805-806 ◽  
pp. 486-491
Author(s):  
Yue Ren Wang ◽  
Yu Feng Jiang ◽  
Min Yu

Using Dest software simulation benchmark building the dynamic heat load, analyzing its distribution pattern, at the same timewe can also get heat pump units in the COP value is different under different working condition, then the soil source heat pump and central heating complementary heating system, undertake in soil source heat pump system design heat load, under theconditions of different proportion of the whole system operation energy consumption, initial investment analysis, we conclude thatthe soil source heat pump and central heating complementary heating systems of different energy matching optimization features,this provides a reference for practical engineering.



Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5552
Author(s):  
Chuanhui Zhu ◽  
Shubin Yan ◽  
Xiaodong Dong ◽  
Wei Zhang ◽  
Biyi Huang ◽  
...  

With the rapid development of industrialization, the excessive use of fossil fuels has caused problems such as increased greenhouse gas emissions and energy shortages. The development and use of renewable energy has attracted increased attention. In recent years, solar heat pump heating technology that uses clean solar energy combined with high-efficiency heat pump units is the development direction of clean heating in winter in northern regions. However, the use of solar energy is intermittent and unstable. The low-valley electricity policy is a night-time electricity price policy. Heat pump heating has problems such as frosting and low efficiencies in cold northern regions. To solve these problems, an exergy analysis model of each component of a phase-change heat-storage coupled solar heat pump heating system was established. Exergy analysis was performed on each component of the system to determine the direction of optimization and improvement of the phase-change heat-storage coupled solar heat pump heating system. The results showed that optimizing the heating-end heat exchanger of the system can reduce the exergy loss of the system. When the phase-change heat-storage tank meets the heating demand, its volume should be reduced to lower the exergy loss of the tank heat dissipation. Air-type solar collectors can increase the income exergies of solar collectors.



2016 ◽  
Vol 19 ◽  
pp. 20-26 ◽  
Author(s):  
Moritz Hein ◽  
Ralf Stöber ◽  
Gerhard Fischerauer ◽  
Johannes Bürner ◽  
Jörg Franke ◽  
...  

The central heating units of buildings are typically replaced every 20 to 30 years. There exists a variety of solutions for fuel-and gas-based units, but it would be advantageous to be able to use renewable energies. This would become possible by the combination of planar carbon-fiber-based infrared (IR) radiant heating foils with a heat pump providing hot water. The main goal of our proposed overall control strategy is to increase the energy efficiency while maintaining the thermal comfort for the residents. We examined the electromagnetic compatibility of the heating foils and simulated the relative contributions of the amount of energy provided by the heat pump and by the heating foils to obtain a maximum coefficient of performance for the combined heating system.



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