scholarly journals Screening refrigerant for a new enhanced ejector heat exchanger used in district heating system based on industrial waste heat

2021 ◽  
Vol 260 ◽  
pp. 01002
Author(s):  
Fangtian Sun ◽  
Baoru Hao ◽  
Xu Chen
Keyword(s):  
Heat Exchanger ◽  
Industrial Waste ◽  
Waste Heat ◽  
District Heating ◽  
Physical Property ◽  
Heating System ◽  
Space Heating ◽  
District Heating System ◽  
Thermodynamic Performance ◽  
Industrial Waste Heat

Performance of the new enhanced ejector heat exchanger is the key to improving performance of the district heating system based on industrial waste heat, and it is significantly affected by thermo-physical property of refrigerant. In this paper, characteristics of the new enhanced ejector heat exchanger are considered, and a new principle for screening refrigerant is proposed. Eleven kinds of refrigerants are firstly selected as candidates, and then they are evaluated from the perspective of property and thermodynamic performance of the new enhanced ejector heat exchanger. The results show that refrigerant property has a greater influence on thermodynamic performance of the new enhanced ejector heat exchanger. Under the condition of low temperature space heating, R152a and R1234yf are favorable choices for the new enhanced ejector heat exchanger. While under conditions of other temperature space heating, R245fa and R600 are better choices for the new enhanced ejector heat exchanger.

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

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.

scholarly journals Novel District Heating Systems: Methods and Simulation Results

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4450
Author(s):  
David Huber ◽  
Viktoria Illyés ◽  
Veronika Turewicz ◽  
Gregor Götzl ◽  
Andreas Hammer ◽  
...  
Keyword(s):  
Thermal Energy ◽  
Industrial Waste ◽  
Waste Heat ◽  
District Heating ◽  
Hot Water ◽  
Space Heating ◽  
Low Grade ◽  
Domestic Hot Water ◽  
Heating And Cooling ◽  
Industrial Waste Heat

Fifth-generation district heating and cooling (5th DHC) systems offer promising approaches to decarbonizing space heating, cooling and domestic hot water supply. By using these systems, clustered buildings combined with industrial waste heat can achieve a net-zero energy balance on a variety of time scales. Thanks to the low exergy approach, these systems are highly efficient. As part of the Smart Anergy Quarter Baden (SANBA) project, the thermal energy grid simulation tool TEGSim has been further developed and used to design an ultra-low-temperature district heating (ULTDH) network with hydraulic and thermal components fitted to the specific regional characteristics of the investigated case. Borehole thermal energy storage (BTES) used as seasonal storage ensures long-term feasibility. The annual discrepancy of input of thermal energy provided by space cooling and output of energy demanded by space heating and domestic hot water is supplied by an external low-grade industrial waste heat source. This paper presents the functionality of the simulation and shows how to interpret the findings concerning the design of all components and their interplay, energy consumption and efficiencies.

scholarly journals Possibilities of Using Industrial Waste Heat for Heating Greenhouses in Northern Greece

2018 ◽  
Vol 10 (4) ◽  
pp. 116 ◽  
Author(s):  
John Vourdoubas
Keyword(s):  
Industrial Waste ◽  
Heat Recovery ◽  
Power Plants ◽  
Waste Heat ◽  
District Heating ◽  
Economic Benefits ◽  
Hot Water ◽  
Northern Greece ◽  
District Heating System ◽  
Industrial Waste Heat

The possibility of using the rejected heat from lignite-fired power plants for heating greenhouses in northern Greece has been examined. Although currently industrial waste heat is used for district heating in a few towns in Greece, its use in agriculture has not been reported so far. Due to many environmental and economic benefits symbiosis of industrial and agricultural activities is promoted in many countries. Greenhouses in northern Greece utilize mainly natural gas as heating fuel. However heat recovery from the existing power plants and its use in greenhouses could increase their energy efficiency and reduce the thermal pollution. It will also decrease the use of fossil fuels in greenhouses and the resulting carbon emissions as well. Their heating requirements have been estimated at 170 W/m2 and the required hot water temperatures are 50-60 oC below the required water temperature in district heating systems, at 120 oC. Currently the price of heat sold in the district heating system in the town of Kozani is 0.0435 €/KWh, which is very attractive for heating greenhouses compared with other existing methods or fuels. It has been estimated that the heat recovery from the power plants at 70 MWth could cover the heating needs of 41.2 ha of modern agricultural greenhouses in northern Greece. Recycling of industrial waste heat in greenhouses in northern Greece, apart from the resulting environmental benefits, will offer a competitive advantage, increasing the profitability of those enterprises.

scholarly journals Overview of Solutions for the Low-Temperature Operation of Domestic Hot-Water Systems with a Circulation Loop

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3350
Author(s):  
Theofanis Benakopoulos ◽  
William Vergo ◽  
Michele Tunzi ◽  
Robbe Salenbien ◽  
Svend Svendsen
Keyword(s):  
Low Temperature ◽  
Heat Loss ◽  
District Heating ◽  
Heating System ◽  
Hot Water ◽  
Heating Power ◽  
Circulation Loop ◽  
Space Heating ◽  
District Heating System ◽  
Domestic Hot Water

The operation of typical domestic hot water (DHW) systems with a storage tank and circulation loop, according to the regulations for hygiene and comfort, results in a significant heat demand at high operating temperatures that leads to high return temperatures to the district heating system. This article presents the potential for the low-temperature operation of new DHW solutions based on energy balance calculations and some tests in real buildings. The main results are three recommended solutions depending on combinations of the following three criteria: district heating supply temperature, relative circulation heat loss due to the use of hot water, and the existence of a low-temperature space heating system. The first solution, based on a heating power limitation in DHW tanks, with a safety functionality, may secure the required DHW temperature at all times, resulting in the limited heating power of the tank, extended reheating periods, and a DH return temperature of below 30 °C. The second solution, based on the redirection of the return flow from the DHW system to the low-temperature space heating system, can cool the return temperature to the level of the space heating system return temperature below 35 °C. The third solution, based on the use of a micro-booster heat pump system, can deliver circulation heat loss and result in a low return temperature below 35 °C. These solutions can help in the transition to low-temperature district heating.

Feasibility limits of using low-grade industrial waste heat in symbiotic district heating and cooling networks

2020 ◽  
Vol 22 (6) ◽  
pp. 1339-1357 ◽  
Author(s):  
Maurizio Santin ◽  
Damiana Chinese ◽  
Alessandra De Angelis ◽  
Markus Biberacher
Keyword(s):  
Industrial Waste ◽  
Waste Heat ◽  
District Heating ◽  
Low Grade ◽  
Heating And Cooling ◽  
Industrial Waste Heat
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