scholarly journals Exploitation of Excess Low-Temperature Heat Sources from Cogeneration Gas Engines

2021 ◽  
Author(s):  
Darko Goričanec ◽  
Danijela Urbancl
Keyword(s):  
Low Temperature ◽  
Cooling System ◽  
District Heating ◽  
Exhaust Pipe ◽  
Gas Engine ◽  
Excess Heat ◽  
Temperature Excess ◽  
Heating Water ◽  
Temperature Heat ◽  
In Series

The chapter presents an innovative technical solution for the use of low-temperature excess heat from the combined heat and power (CHP) of gas engines using gas or liquid fuel for district heating, building heating or industry. The primary fuel efficiency of CHP gas engines for heat production can be significantly increased by using the low-temperature excess heat of the exhaust gasses and the cooling system of the CHP gas engine, which are released into the environment thereby also reducing CO2 emissions. District heating hot water systems generally work with higher temperatures of the heating water, which is transported to the heat consumer via the supply line, and the cooled heating water is returned to the CHP gas engine via the return line. In order to make use of the excess low-temperature heat of the exhaust gasses and the cooling system of the CHP gas engine, a condenser must be installed in the exhaust pipe in which the water vapor contained in the exhaust gasses condenses and a mixture of water and glycol is heated, which later leads to the evaporator of the high-temperature heat pump (HTHP). The cooled heating water is returned from the heat consumer via the district heating return pipe to a condenser of one or more HTHPs connected in series, where it is reheated and then sent to a CHP gas engine, where it is reheated to the final temperature. The Aspen plus software package is used to run a computer simulation of one or more HTHPs connected in series and parallel to the district heating system and to demonstrate the economics of using the excess heat from the exhaust gasses and the cooling system of the CHP gas engine.

scholarly journals Recommendations for Running a Tandem of Adsorption Chillers Connected in Series and Powered by Low-Temperature Heat from District Heating Network

Energies ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4791
Author(s):  
Bartlomiej Nalepa ◽  
Tomasz Halon
Keyword(s):  
Cooling System ◽  
District Heating ◽  
Negative Influence ◽  
Asynchronous Operation ◽  
Heating Water ◽  
In Series ◽  
Water Mass Flow Rate ◽  
Operating Cycles ◽  
Secondary Device ◽  
Selection Of

In this paper, we investigate implications of running a cooling system of two silicagel/water adsorption chillers powered by a district heating network. The devices are connected in series, i.e., the heating water output from the primary chiller is directed to the secondary one. In consequence, the secondary device must deal with an even lower driving temperature and with temperature fluctuations caused by the primary device. We have evaluated three factors that influence the operation of those coupled devices: synchronization of their operating cycles, selection of their cycle time allocations (CTAs), and changing the heating water mass flow rate. Numerical analyses indicate that the performance of the secondary chiller drops significantly if the coupled devices that use the same CTA run asynchronously. The decrease is largest if the shift between the operating cycles is x=0.375 and x=0.875. We found that it is possible to reduce the negative influence of the asynchronous operation by implementing different CTA in each chiller. The best performance is achieved if the primary chiller uses an adsorption time to desorption time ratio f=1.0 and the secondary chiller uses f = 0.6–0.7.

scholarly journals The Exploitation of Low-Temperature Hot Water Boiler Sources with High-Temperature Heat Pump Integration

Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6311
Author(s):  
Darko Goričanec ◽  
Igor Ivanovski ◽  
Jurij Krope ◽  
Danijela Urbancl
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Heat Pump ◽  
Flue Gas ◽  
Hot Water ◽  
Flue Gases ◽  
Excess Heat ◽  
Heating Water ◽  
Temperature Heat ◽  
High Temperature Heat Pump

The article presents an original and innovative technical solution for the exploitation of low-temperature excess heat from hot water boilers that use gas or liquid fuel for the needs of high-temperature heating in buildings or in industry. The primary fuel efficiency used for hot water boilers can be significantly increased by utilizing the excess low-temperature heat of flue gases that are discharged into the environment and thus also reduce CO2 emissions. Hot water systems usually operate at higher temperatures of the heating water, which is transported to the heat consumer via supply pipe, and the cooled heating water is returned to the hot water boiler via the return pipe. For the excess low-temperature heat exploitation of the flue gases from hot water boiler, it is necessary to install a condenser in the flue gas discharge pipe, where condensation of water vapour present in the flue gas heats water or a mixture of water and glycol. The heating water, which is cooled and returned from the heat consumer via the return pipe, is led to the condenser of the high-temperature heat pump, where it is preheated and then led to the hot water boiler, where it is heated to the final temperature. A computer simulation with the Aspen plus software package for the series or parallel connection of high-temperature heat pump to a hot water heating system and the economic analysis of the excess heat exploitation from the flue gases are also performed.

Systematic optimization for the utilization of low-temperature industrial excess heat for district heating

Energy ◽  
2018 ◽  
Vol 144 ◽  
pp. 984-991 ◽  
Author(s):  
Yemao Li ◽  
Jianjun Xia ◽  
Yingbo Su ◽  
Yi Jiang
Keyword(s):  
Low Temperature ◽  
District Heating ◽  
Excess Heat ◽  
Systematic Optimization

scholarly journals Low-temperature excess heat capacity in fresnoite glass and crystal

2014 ◽  
Vol 4 (1) ◽  
Author(s):  
Kensaku Nakamura ◽  
Yoshihiro Takahashi ◽  
Takumi Fujiwara
Keyword(s):  
Heat Capacity ◽  
Low Temperature ◽  
Excess Heat Capacity ◽  
Excess Heat ◽  
Temperature Excess

Origin of the low temperature excess heat capacity of isotopically substituted acetylsalicylic acid

2011 ◽  
Vol 514 (1-3) ◽  
pp. 62-65
Author(s):  
F. Schröder ◽  
B. Winkler ◽  
J.D. Bauer ◽  
E. Haussühl ◽  
B. Rivera Escoto ◽  
...  
Keyword(s):  
Heat Capacity ◽  
Low Temperature ◽  
Acetylsalicylic Acid ◽  
Excess Heat Capacity ◽  
Excess Heat ◽  
Temperature Excess

scholarly journals Design of 10 kW Low Temperature Power Cycle Using Amine— CO2 Fluid

2021 ◽  
Vol 333 ◽  
pp. 09002
Author(s):  
Takashi Ogawa ◽  
Takashi Mawatari ◽  
Akira Itoh ◽  
Yasushi Yamamoto
Keyword(s):  
Low Temperature ◽  
Flow Rate ◽  
Organic Rankine Cycle ◽  
Rankine Cycle ◽  
Expansion Ratio ◽  
Hot Water ◽  
Cross Sectional ◽  
Gas Engine ◽  
Power Cycle ◽  
Temperature Heat

Our thermodynamic study indicated that low temperature power cycle using amine-CO2 fluid can obtain the performance equal to or higher than that of the current organic Rankine cycle. We designed a 10 kW test equipment. We set high temperature heat source is hot water at the temperature of 90°C and the flow rate of 8,200kg/h, which is a coolant from a gas engine. The heat and mass balance of the equipment was calculated thermodynamically. The result showed the power of 10.5kW and the system efficiency of 7.3 per cent at the the amine – CO2 fluid flow rate of 1,000kg/h, and the turbine expansion ratio of 4.8. The preliminary estimation shows as follows. The diameter and rotational speed of the turbine blade are 0.115m and 54,400min-1, respectively. The number, width, and length of the recuperator plates are 20, 117mm, and 835mm, respectively. The height and cross sectional area of the absorption bed are 0.35m and 0.027m2, respectively.

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