Industrial excess heat recovery in industry-city networks: a technical, environmental and economic assessment of heat flexibility

Aiming for the better environmental and economic performance of traditional engines, waste heat recovery (WHR) technologies are actively studied to find their most beneficial applications. In this work, the inverted Brayton cycle (IBC) is investigated as a potential WHR solution for liquefied natural gas (LNG) fuelled transport truck. LNG being one of the less polluting fossil fuels is widely spreading nowadays in different industries due to the rapid development of the LNG supply chain in the world. LNG-fuelled cargo transportation follows this prevailing trend. Based on the overexpansion of flue gases to subatmospheric pressure, inverted Brayton cycle, in turn, is considered a prospective technology of WHR and techno-economic analysis of IBC in several configurations on-board of a heavy transport truck have been assessed. IBC is integrated into the engine cooling system in the basic layout, and additionally, it incorporates LNG regasification process in advanced configurations. Power balance based on Aspen Hysys model enables to perform system optimisation and gives preliminary design parameters of the system components. Cost function approach provides the basis for a preliminary economic assessment of the layouts. Although the system shows fuel economy of maximum about 2.1 %, analysis revealed the necessity to continue the search for better technical solutions in IBC-based systems to make them economically attractive due to high cost of installed equipment.

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Techno-Economic Analysis of Waste Heat Utilization in Data Centers: Application of Absorption Chiller Systems

Energies ◽

10.3390/en14092433 ◽

2021 ◽

Vol 14 (9) ◽

pp. 2433

Author(s):

Leyla Amiri ◽

Edris Madadian ◽

Navid Bahrani ◽

Seyed Ali Ghoreishi-Madiseh

Keyword(s):

Heat Recovery ◽

Data Centers ◽

Waste Heat ◽

Ghg Emissions ◽

Economic Assessment ◽

Electrical Energy ◽

Absorption Chiller ◽

Waste Heat Utilization ◽

Annual Reduction ◽

Electrical Energy Production

Modern data centers are playing a pivotal role in the global economic situation. Unlike high-quality source of waste heat, it is challenging to recover the decentralized and low-quality waste heat sourced from data centers due to numerous technological and economic hurdles. As such, it is of the utmost importance to explore possible pathways to maximize the energy efficiency of the data centers and to utilize their heat recovery. Absorption chiller systems are a promising technology for the recovery of waste heat at ultra-low temperatures. In fact, the low temperature heat discharged from data centers cannot be retrieved with conventional heat recovery systems. Therefore, the present study investigated feasibility of waste heat recovery from data centers using an absorption chiller system, with the ultimate goal of electrical energy production. To fulfill this objective, a techno-economic assessment of heat recovery using absorption chiller (AC) technique for the data centers with power consumption range of 4.5 to 13.5 MW is performed. The proposed AC system enables saving electricity for the value of 4,340,000 kWh/year and 13,025,000 kWh/year leading to an annual reduction of 3068 and 9208 tons CO2 equivalent of greenhouse gas (GHG) emissions, respectively. The results of this study suggest an optimum change in the design of the data center while reducing the payback period for the investors.

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