The future of low carbon industrial process heat: A comparison between solar thermal and heat pumps

Meyers, Steven P.; Schmitt, Bastian; Vajen, Klaus

doi:10.1016/j.solener.2018.08.011

Cited by 31 publications

(11 citation statements)

References 32 publications

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“…Nader et al made an assessment of the existing photovoltaic air conditioning system [5]. The solar energy driven system is a promising one among them [6]. Much research has been done in recent years.…”

Section: Introductionmentioning

confidence: 99%

Research on Local Heating Regeneration Method for Air-Conditioning Systems

Cheng

2021

Processes

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Absorption air-conditioning systems have a great advantage in terms of energy conservation and environmental protection. However, the large amount of energy waste in the thermal regeneration process leads to lower efficiency and impedes its development. To reduce energy loss and improve performance, a local heating regeneration method is proposed in this paper. The main principle is reducing the volume of the liquid participating regeneration. Including the solar steam mode, two modes are introduced and configured. Theoretical and experimental research has been made on the new methods. Models have been developed for comparison analysis. Experiments have been conducted on water and absorbent solution with different modes. Performance has been evaluated based on the experimental data. The results expose the influence of different parameters, like liquid volume and solution concentration, on the regeneration process. The local heating method improved the regeneration efficiency by 40% in the no solar steam mode and the performance tripled in the solar steam mode. The COP (the ratio of cooling load to energy consumption) of the absorption system with the solar steam mode is more than two times of that with the traditional regeneration mode. It shows the local heating regeneration method has good potential in future application.

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Section: Introductionmentioning

confidence: 99%

Research on Local Heating Regeneration Method for Air-Conditioning Systems

Cheng

2021

Processes

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“…With the United Nations, this target to hold means global temperature will rise by the end of the century to at least 2 • C [2]. These facts represent an essential driving force for the gradual implementation of safe and feasible alternatives in all power-consuming sectors [3] in addition to policies that help industries implement strategies to improve the efficiency of energy use through innovative technologies. Where they are integrated within national and foreign policies, and with the mechanisms of ecological technological innovation to give demand to energy saving and emissions reduction [4].…”

Section: Introductionmentioning

confidence: 99%

A Simplified Method to Avoid Shadows at Parabolic-Trough Solar Collectors Facilities

2020

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Renewable energy today is no longer just an affordable alternative, but a requirement for mitigating global environmental problems such as climate change. Among renewable energies, the use of solar energy is one of the most widespread. Concentrating Solar Power (CSP) systems, however, is not yet fully widespread despite having demonstrated great efficiency, mainly thanks to parabolic-trough collector (PTC) technology, both on a large scale and on a small scale for heating water in industry. One of the main drawbacks to this energy solution is the large size of the facilities. For this purpose, several models have been developed to avoid shadowing between the PTC lines as much as possible. In this study, the classic shadowing models between the PTC rows are reviewed. One of the major challenges is that they are studied geometrically as a fixed installation, while they are moving facilities, as they have a tracking movement of the sun. In this work, a new model is proposed to avoid shadowing by taking into account the movement of the facilities depending on their latitude. Secondly, the model is tested to an existing facility as a real case study located in southern Spain. The model is applied to the main existing installations in the northern hemisphere, thus showing the usefulness of the model for any PTC installation in the world. The shadow projected by a standard, the PTC (S) has been obtained by means of a polynomial approximation as a function of the latitude (Lat) given by S = 0.001 − Lat2 + 0.0121 − Lat + 10.9 with R2 of 99.8%. Finally, the model has been simplified to obtain in the standard case the shadows in the running time of a PTC facility.

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“…The diversity of heat demands can increase site energy efficiency [9]. According to Meyers et al [15], a higher number of heat pumps operating hours makes it a promising solution for low carbon industrial process heat, and despite the relatively higher energy efficiency of heat pump technology, it is only profitable above 4000 h per year [16]. However, the maximum yearly operation is limited because these systems only can work if the heat sink is requiring energy.…”

Section: Introductionmentioning

confidence: 99%

Multi-objective optimization of a novel reversible High-Temperature Heat Pump-Organic Rankine Cycle (HTHP-ORC) for industrial low-grade waste heat recovery

Mateu-Royo

Navarro-Esbrí

Peris

et al. 2019

Energy Conversion and Management

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Nowadays, a high amount of industrial thermal energy is still lost due to the lack of competitive solutions for energy revalorization. Facing this challenge, this paper presents a novel technology, based on a reversible High-Temperature Heat Pump (HTHP) and Organic Rankine Cycle (ORC). The proposed system recovers low-grade waste heat to generate electricity or useful heat in accordance with consumer demand. Compressor and expander semi-empirical models have been considered for the reversible system computational simulation, being HFC-245fa the working fluid selected. The built-in volume ratio and Internal Heat Exchanger (IHX) effectiveness have been optimized to reach the maximum energy efficiency in each operating condition. Although HFC-245fa exhibits energy performance attributes, its high Global Warming Potential (GWP) is an issue for climate change mitigation. Hence, multi-objective optimisation of the environmentally friendly working fluids Butane, Pentane, HFO-1336mzz(Z), R-514A, HCFO-1233zd(E) and HCFO-1224yd(Z) has been carried out. The results show that the system proposed, working with HFC-245fa, achieves a Coefficient of Performance (COP) of 2.44 for condensing temperature of 140 °C, operating in HTHP mode, whereas the ORC mode provides a net electrical efficiency of 8.7% at condensing temperature of 40 °C. Besides, HCFO-1233zd(E) and HCFO-1224yd(Z) are both appropriate alternatives for the HFC-245fa replacement. These working fluids provide a COP improvement of 9.7% and 5.8% and electrical net efficiency improvement of 2.1% and 0.8%, respectively, compared to HFC-245fa. This paper provides a reference study for further designs and developments of reversible HTHP-ORC systems used for industrial low-grade waste heat recovery.

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The future of low carbon industrial process heat: A comparison between solar thermal and heat pumps

Cited by 31 publications

References 32 publications

Research on Local Heating Regeneration Method for Air-Conditioning Systems

Research on Local Heating Regeneration Method for Air-Conditioning Systems

A Simplified Method to Avoid Shadows at Parabolic-Trough Solar Collectors Facilities

Multi-objective optimization of a novel reversible High-Temperature Heat Pump-Organic Rankine Cycle (HTHP-ORC) for industrial low-grade waste heat recovery

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