Heat pumps in combined heat and power systems

Ommen, Torben Schmidt; Markussen, Wiebke Brix; Elmegaard, Brian

doi:10.1016/j.energy.2014.09.016

Cited by 68 publications

(24 citation statements)

References 13 publications

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“…A number of energy system studies e.g., Blarke & Lund (2007) [7], Kiviluoma & Meibom (2010) [8], Münster et al (2012) [9], and Blarke (2012) [10], show that heat pumps are profitable for a system. This is also found under some conditions for more detailed analyses of the plants in the system as in Ommen et al (2014) [4] and Ommen (2015) [11], even if challenges are apparent. For other countries the potential of heat pumps as a mean to use to reach lower greenhouse gas emissions has also been acknowledged, e.g.…”

Section: Introductionmentioning

confidence: 82%

“…When integrating combined heat and power plants with heat pumps, several configurations are possible [4]. By directly combining the two technologies, increased performance of the combined system may be achieved, compared to when operated individually, but the performance is gained at the expense of an increased amount of operational constraints for the heat pump unit.…”

Section: Introductionmentioning

confidence: 99%

“…Investigations of the possible integrations is found in Ommen et al (2014) [4] and Ommen (2015) [11]. A mapping of the heat sources available in Denmark is provided in Bühler et al (2015) [16].…”

Section: Introductionmentioning

confidence: 99%

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Integration of large-scale heat pumps in the district heating systems of Greater Copenhagen

Bach

Werling²,

Ommen

et al. 2016

Energy

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109

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This study analyses the technical and private economic aspects of integrating a large capacity of electric driven heat pumps (HP) in the Greater Copenhagen district heating (DH) system, which is an example of a state-of-the-art large district heating system with many consumers and suppliers. The analysis was based on using the energy model Balmorel to determine the optimum dispatch of HPs in the system. The potential heat sources in Copenhagen for use in HPs were determined based on data related to temperatures, flows, and hydrography at different locations, while respecting technical constraints. The Balmorel model was developed further in order to provide a better representation of HPs, for analysing the seasonal variations of COP, and to represent the difference in performance of HPs connected to either distribution or transmission networks. The optimization yields roughly 3,500 full load hours (FLH) for the HPs connected to the DH distribution networks when considering a current scenario. In a zero carbon-dioxide emission scenario expected in year 2025, approximately 4,000 FLH, are achieved. In the case where HPs are connected to the DH transmission network at elevated temperatures, their operation decreases by roughly 1,000 FLH. No significant impact was found when comparing fixed and varying operation characteristics of the HP.

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Section: Introductionmentioning

confidence: 82%

Section: Introductionmentioning

confidence: 99%

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Integration of large-scale heat pumps in the district heating systems of Greater Copenhagen

Bach

Werling²,

Ommen

et al. 2016

Energy

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109

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“…5 similar to the one used in previous studies, e.g. [25,26,27]. The operating conditions of a heat pump can be evaluated based on six parameters: The temperature of the sink process stream (DH) leaving the condenser T sink , the temperature of the source entering the evaporator T source , the process stream temperature glides from inlet to outlet in both heat exchangers (∆T sink and ∆T source ), and expressions defining the heat transfer 165 capacity of the two heat exchangers, in this case the minimum temperature differences, ∆T pinch, cond and ∆T pinch, evap .…”

Section: Performance Of Hps For Finite Energy Reservoirs 160mentioning

confidence: 92%

“…4. The model used for this analysis corresponded closely to the one used in [25,7]. The steam enters the 140 intermediate (IP2) and low pressure part (LP1 + LP2) of the turbine train after expansion in the preceding turbine (IP1), and may be used for power generation or to supply district heating.…”

Section: Heat Supply From Extraction Chpmentioning

confidence: 99%

Performance of ultra low temperature district heating systems with utility plant and booster heat pumps

Ommen¹,

Thorsen

Markussen³

et al. 2017

Energy

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Document Version Peer reviewed versionLink back to DTU Orbit Citation (APA): Ommen, T. S., Thorsen, J. E., Markussen, W. B., & Elmegaard, B. (2017). Performance of ultra low temperature district heating systems with utility plant and booster heat pumps. Energy, 137, 544-555.Please cite this article as: Ommen T, Thorsen JE, Markussen WB, Elmegaard B, Performance of ultra low temperature district heating systems with utility plant and booster heat pumps, Energy (2017), AbstractThe optimal integration of booster heat pumps in ultra low temperature district heating (ULTDH) was investigated and compared to the performance of low temperature district heating. Two possible heat production technologies for the DH networks were analysed, namely extraction combined heat and power (CHP) and central heat pumps (HPs). The analysis focussed on the characteristic heat demands of newly build multi-story buildings and the results were based on the ratio of the individual demands compared to the total. It was found that the optimal return temperature was dependent on the forward temperature and the heat consumption profile. For reference conditions, the optimal return of ULTDH varies between 21°C and 27°C. When using a central HP to supply the DH system, the resulting coefficient of system performance (COSP) was in the range of 3.9 (-) to 4.7 (-) for equipment with realistic component efficiencies and effectiveness, when including the relevant parameters such as DH system pressure and heat losses. By using ULTDH with booster HPs, performance improvements of 12 % for the reference calculations case were found, if the system was supplied by central HPs. Opposite results were found for extraction CHP, were ULTDH with booster HPs resulted in decreasing COSP of 20 %. Keywords: 4gDH, Ultra low temperature district heating, Heat pumps, Combined heat and power 15 well as to allow more heat sources to be easily integrated in the heat network [6]. Lowering DH supply * Corresponding author Email addresses: tsom@mek.dtu.dk (Torben Ommen), jet@Danfoss.com (Jan Eric Thorsen), wb@mek.dtu.dk (Wiebke Brix Markussen), be@mek.dtu.dk (Brian Elmegaard)

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