Benchmarking and Potential of Heat Pumps for Flue Gas Condensation

Abstract

The use of environmental or waste heat with heat pumps, open absorption cycles or sorption heat pumps is an option for low carbon or high efficiency heat supply for industrial use. For one of the mentioned technologies to experience wide spread use it must offer economic advantages compared to other technologies. The evaluation of the economic viability is strongly dependent on boundary conditions.

This work presents a method for the comparison of available technologies with regard to economics and potential for exhaust heat use. Calculations comparing the effects of different exhaust gas compositions resulting from technology specific air ratios for combustion in combination with different return and process heat temperatures are performed in order to quantify the potential of condensing technology. The herein developed specific annuity difference method allows evaluating the impact of improving technology specific parameters, such as temperature spread and coefficient of performance (COP), enabling to identify future research needs and to benchmark the technologies with e.g. a gas heater. The risk posed by uncertain future developments, such as gas price development and increasing prices for carbon emissions, possible taxation of these and emission trading, influences the economic evaluation and can motivate investment in active condensing technology, even if economic viability under current circumstances is not given.

Keywords

• condensing technology,energy efficiency,heat pump,waste heat

References

1. [1] Q. Chen, K. Finney, H. Li, X. Zhang, J. Zhou, V. Sharifi, J. Swithenbank, “Condensing boiler applications in the process industry,” Applied Energy, doi: 10.1016/j.apenergy.2010.11.020.
2. [2] B. Hebenstreit, R. Schnetzinger, R. Ohnmacht, E. Höftberger, J. Lundgren, W. Haslinger, A. Toffolo, “Techno-economic study of a heat pump enhanced flue gas heat recovery for biomass boilers,” Biomass & Bioenergy, doi: 10.1016/j.biombioe.2014.01.048.
3. [3] M. Wei, X. Zhao, L. Fu, S. Zhang, “Performance study and application of new coal-fired boiler flue gas heat recovery system,” Applied Energy, doi: 10.1016/j.apenergy.2016.11.132.
4. [4] Y. Li, M. Yan, L. Zhang, G. Chen, L. Cui, Z. Song, J. Chang, C. Ma, “Method of flash evaporation and condensation – heat pump for deep cooling of coal-fired power plant flue gas: Latent heat and water recovery,” Applied Energy, DOI: 10.1016/j.apenergy.2016.03.017.
5. [5] D. Panepinto, M.C. Zanetti, Municipal solid waste incineration plant: “A multi-step approach to the evaluation of an energy-recovery configuration,” Waste Management, doi: 10.1016/j.wasman.2017.07.036.
6. [6] VDI-GBG, VDI Richtlinie 6025 - Economy calculation systems for capital goods and plants. Düsseldorf, Germany, VDI-Verlag, 2012.
7. [7] BMWi, Strompreise für Industriekunden in ausgewählten europäischen Ländern nach Verbrauchsmenge im Jahr 2016 (in Euro-Cent pro Kilowattstunde). [Online]. Available: https://de.statista.com/statistik/daten/studie/151260/umfrage/strompreise-fuer-industriekunden-in-europa/ (accessed Feb. 08, 2018).
8. [8] A. Kossoy, G. Peszko, K. Oppermann, N. Prytz, N. Klein, K. Blok, L. Lam, L. Wong, B. Borkent, State and Trends of Carbon Pricing. Washington DC, USA, World Bank Group, 2015 Sep. Report No.: 99533.

9. [9] D. Hirst, Carbon Price Floor (CPF) and the price support mechanism. London, UK, House of Commons Library, 2018 Jan. Briefing Paper No.: 05927.
10. [10] Macrotrends. Natural Gas Prices – Historical Chart. [Online]. Available: http://www.macrotrends.net/2478/ natural-gas-prices-historical-chart'>Natural Gas Prices – Historical Chart (accessed Feb. 09, 2018).
11. [11] Generalzolldirektion, Steuersätze für Energieerzeug-nisse nach § 2 Abs. 1 EnergieStG. [Online]. Available: http://www.zoll.de/DE/Fachthemen/Steuern/Verbrauchsteuern/Energie/Grundsaetze-Besteuerung/Steuerhoehe/steuerhoehe_node.html (accessed Feb. 09, 2018).