Technical and economic working domains of industrial heat pumps: Part 1 – Single stage vapour compression heat pumps

Ommen, Torben Schmidt; Jensen, Jonas Kjær; Markussen, Wiebke Brix; Reinholdt, Lars; Elmegaard, Brian

doi:10.1016/j.ijrefrig.2015.02.012

Cited by 73 publications

(38 citation statements)

References 15 publications

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“…This is the case of T max,hp , p min,hp , and p min,orc , which set the boundary for system temperature and pressure design levels. For example, T max,hp sets the maximum compressor discharge temperature to 180 • C because lubricant oil degradation may occur at higher temperatures (Jensen et al, 2015;Ommen et al, 2015), although oil-free compressors could be used. In this case, the maximum compressor discharge temperature could reach 200 • C since several HT-VCHP working fluids start to decompose over such temperatures (Frate et al, 2019a).…”

Section: Modeling Hypothesesmentioning

confidence: 99%

Multi-Criteria Economic Analysis of a Pumped Thermal Electricity Storage (PTES) With Thermal Integration

2020

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The interest toward large-scale electric energy storage technologies is increasing with the large deployment of new renewable capacity. In case of several hours of storage duration, there is no consensus on which technology is the most suited. Several technologies have been recently proposed, among which is pumped thermal electricity storage (PTES), which is a technology based on the idea of storing electrical energy as heat. PTES is usually less efficient than electrochemical batteries, but it is characterized by a lower cost per kilowatt hour, which could make it a suitable alternative for applications with long storage duration. In this study, a recently proposed PTES system based on the use of heat pumps and organic Rankine cycles is investigated from a thermo-economic point of view. The system is powered by both electric and low-grade thermal energy, thus taking advantage of waste heat to increase the electric performance. As the system design both affects efficiency and cost, a trade-off must be found. In this study, this task was performed by means of a multi-objective optimization approach. The relation between electrical round-trip efficiency and system cost is analyzed, and the impact of several design specifications such as boundary conditions, nominal power rating, and storage duration is discussed. Finally, the results are generalized by defining some cost scaling correlations. Large-size configurations (5 MW of charging power for 8 h of storage) may achieve equipment purchasing costs as low as 140 e/kWh and 2,300 e/kW, with an electrical round-trip efficiency of 0.6. These results show that the investigated technology may be suitable in the context of large-scale and long-duration energy storage.

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Section: Modeling Hypothesesmentioning

confidence: 99%

Multi-Criteria Economic Analysis of a Pumped Thermal Electricity Storage (PTES) With Thermal Integration

2020

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“…The implementation of heat pumps in spray-drying facilities is typically restricted by the high temperature of the exhaust air (80-100°C), which is out of the working domain for most industrial vapour compression heat pumps [3,4]. The ammonia-water hybrid absorption-compression heat pump (HACHP), however, has several attributes making it applicable for high-temperature operation [3,5].…”

Section: Copmentioning

confidence: 99%

“…These investigations have been limited to low-temperature drying processes due to the constrained heat supply temperature of conventional vapour compression heat pumps. The maximum supply temperature of vapour compression heat pumps is bound by the maximum allowable pressure of the compressor technology and the corresponding saturation temperature of the refrigerant [4].…”

Section: Copmentioning

confidence: 99%

“…pressure) heat supply temperatures up to 150°C can be achieved using the HACHP [5]. The limit for a pure ammonia system with these components is 90°C [4]. The development of these high pressure components and their combination with the HACHP technology has thereby shifted the working domain of industrial heat pumps, making it applicable for processes like spray-drying.…”

Section: Copmentioning

confidence: 99%

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Exergoeconomic optimization of an ammonia–water hybrid absorption–compression heat pump for heat supply in a spray-drying facility

Jensen

Markussen

Reinholdt

et al. 2015

Int J Energy Environ Eng

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Spray-drying facilities are among the most energy intensive industrial processes. Using a heat pump to recover waste heat and replace gas combustion has the potential to attain both economic and emissions savings. In the case examined a drying gas of ambient air is heated to 200°C yielding a heat load of 6.1 MW. The exhaust air from the drying process is 80°C. The implementation of an ammonia-water hybrid absorption-compression heat pump to partly cover the heat load is investigated. A thermodynamic analysis is applied to determine optimal circulation ratios for a number of ammonia mass fractions and heat pump loads. An exergoeconomic optimization is applied to minimize the lifetime cost of the system. Technological limitations are imposed to constrain the solution to commercial components. The best possible implementation is identified in terms of heat load, ammonia mass fraction and circulation ratio. The best possible implementation is a 895 kW heat pump with an ammonia mass fraction of 0.82 and a circulation ratio of 0.43. This results in economic savings with a present value of 146,000 € and a yearly CO 2 emissions reduction of 227 ton.Keywords Spray-drying Á Hybrid heat pump Á Exergoeconomics Á High-temperature heat pump Á Ammonia-water Á Absorption

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“…Detailed thermodynamic and economic models of various single stage VCHP and HACHP were developed and investigated in Ommen et al [21] and Jensen et al [22]. The results show, that the best available technology in terms of net present value (NPV), typically depends on the performance and investment of the HP systems at the specific layout of the sink/source process streams.…”

Section: Introductionmentioning

confidence: 99%

Design of serially connected district heating heat pumps utilising a geothermal heat source

Jensen

Ommen

Markussen

et al. 2017

Energy

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The design of two heat pumps (HP), connected in series, was investigated for operation in the district heating (DH) network of the Greater Copenhagen area, Denmark. The installation was dimensioned to supply 7.2 MW of heat at a temperature of 85 • C. The heat pumps utilise a geothermal heat source at 73 • C. Both heat source and sink experience a large temperature change, which may lead to decreased performance for single vapour compression HP. The performance may be increased by using HPs connected in series and by applying HPs with zeotropic mixtures. First a generic study with a simple representation of the HP was applied to investigate optimal system configurations. It was shown that using two heat pumps in series with direct heat exchange in parallel with the first heat pump could increase the performance compared to the HP performance. Detailed thermodynamic models of a zeotropic mixture HP predicted that an exergetic efficiency of the units between 50 % and 65 % is possible. The technical feasibility as well as the economic viability of this installation was investigated for a range of optimal configurations. The analysis recommends a heat pump configuration with a system exergetic efficiency of 63 %.

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Technical and economic working domains of industrial heat pumps: Part 1 – Single stage vapour compression heat pumps

Cited by 73 publications

References 15 publications

Multi-Criteria Economic Analysis of a Pumped Thermal Electricity Storage (PTES) With Thermal Integration

Multi-Criteria Economic Analysis of a Pumped Thermal Electricity Storage (PTES) With Thermal Integration

Exergoeconomic optimization of an ammonia–water hybrid absorption–compression heat pump for heat supply in a spray-drying facility

Design of serially connected district heating heat pumps utilising a geothermal heat source

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