Desiccant-Assisted Air Conditioning System Relying on Solar and Geothermal Energy during Summer and Winter

Niemann, Peter; Richter, Finn; Speerforck, Arne; Schmitz, Gerhard

doi:10.3390/en12163175

Cited by 11 publications

(4 citation statements)

References 34 publications

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“…The evaluation index of dehumidification performance should be able to reflect the thermal energy efficiency of the desiccant wheel. The ratio of the latent heat taken away by the desiccant wheel to the regeneration heat used in the literature is an appropriate method [29]. In this study, the dehumidification coefficient of performance, which is defined as the ratio of the latent load treated by the desiccant wheel to the condenser heat required to regenerate the desiccant, was used to evaluate the dehumidification performance of the desiccant wheel.…”

Section: System Performance Evaluation Parametersmentioning

confidence: 99%

Effect of Evaporator Position on Heat Pump Assisted Solid Desiccant Cooling Systems

2020

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The packaged terminal air conditioning with reheat (PTACR) system, as a commonly used dehumidification system, faces the problem of extra energy consumption in the deep-cooling and reheating processes. Therefore, different heat pump assisted hybrid solid desiccant cooling (HPDC) systems were proposed and their characteristics were investigated via EnergyPlus simulations. The system energy efficiency presents an upward trend with the increase in outdoor temperature and humidity. A high-humidity climate leads to the improvement of system performance. The dehumidification performance of the desiccant wheel in the HPDC system declines when outdoor humidity increases. Compared with the PTACR system, the energy consumption of the HPDC system in which the evaporator was placed upstream of the desiccant wheel is reduced by 36%, 66%, and 64%, respectively, under different high-humidity climates. The system maintained the indoor environment within the comfort zone, and eliminated the need for a heat source for desiccant regeneration. In conclusion, the HPDC system is an available alternative that considers both energy consumption and system performance. Placing the evaporator upstream of the desiccant wheel is more advantageous in high-temperature and high-humidity climates.

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Section: System Performance Evaluation Parametersmentioning

confidence: 99%

Effect of Evaporator Position on Heat Pump Assisted Solid Desiccant Cooling Systems

2020

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“…However, if the temperature of the heat source drops consistently, it may be necessary to support regeneration, e.g., with solar collectors in the summer. The available literature, e.g., [54,[71][72][73][74][75][76][77], shows that in cold regions it seems necessary for long-term use.…”

Section: Introductionmentioning

confidence: 99%

Assessment of Ground Regeneration around Borehole Heat Exchangers between Heating Seasons in Cold Climates: A Case Study in Bialystok (NE, Poland)

Piotrowska-Woroniak

2021

Energies

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Based on the experimental studies, the process of ground regeneration around the borehole loaded with brine-water heat pumps working exclusively for heating purposes in the period of four consecutive heating seasons in a cold climate was presented. The research was conducted in north-eastern Poland. The aim of the work is to verify the phenomenon of thermal ground regeneration in the period between heating seasons on the basis of the recorded data and to check whether the ground is able to regenerate itself and at what rate. It was noticed that the ground does not fully regenerate, especially during heating seasons with lower temperatures. In the analyzed period, from 22 September 2016 to 12 October 2020, the ground probably cooled irreversibly by 1.5 °C. In order to illustrate and evaluate the speed of changes in the ground, the one’s profile with an undisturbed temperature field was presented for each month of the year. The presented results can be a very important source of information for the analysis of geothermal conditions occurring in the ground. They can be used to verify mathematical models and conduct long-term simulations that allow us to see the complexity of the processes taking place in the ground.

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“…The rotor materials employed thus far have been limited to lithium chloride or silica gel, which are integrated into a cellulose medium. Various researchers have conducted studies in which liquid desiccants were applied to desiccant evaporative cooling systems, including [30,31], while others have applied desiccant wheels, including [32,33].…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Coupling PV and Air Conditioning vs. Solar Cooling Systems—Case Study from Jordan

et al. 2021

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When they were first conceived, solar cooling systems were designed to be cost-effective and environmentally safe alternatives for the majority of the developing nations that are characterised by their hot climates in contrast with the traditional air conditioning systems powered by electricity that is produced from fossil fuel resources. Nevertheless, developments in photovoltaic (PV) and air-conditioning technologies have impacted on the prospects of solar cooling systems. This study examined two different options: a coupled PV and air conditioner system and a solar cooling system (absorption chillers where thermal energy is provided by solar collectors) for a specific developing country located in the Eastern Mediterranean region whose climate is hot and dry (Jordan). The cooling system comprised a pair of cooled multistage compression, both of which were 700 kW, while the PV system’s size was 2.1 MWp, the utility grid connection was a 0.4 kV 50 Hz net meter (2 m) and it was anticipated that 3300 MWh/year would be generated. The solar cooling system operated at a maximum coefficient of performance (COP) of 0.79 and had an actual recorded COP of 0.32 on the site; when the electricity tariff of $0.1/kWh was considered, the respective levelised cost of energy (LCOE) values were $0.9/kWh and $2.35/kWh respectively. The findings indicate that the initial costs for the solar thermal cooling system and the PV system were approximately $3.150M and $3M, respectively. The current value of future cash payments when discounts of 6% per year were applied to the payments for the combination of PV and air conditioning was about $9,745,000, whereas the solar thermal cooling system will not reach the breakeven point at negative $1,730,000. It is clear the absorption chiller did not display economic feasibility, whereas the value for the coupled PV and air-conditioning systems was under $0.05/kWh. In addition to the extensive maintenance needs, the reduced COP and the practicality and feasibility of the solar thermal cooling systems mean these kinds of technologies are under significant pressure to remain competitive when faced with the development of new air conditioning and PV technologies.

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Desiccant-Assisted Air Conditioning System Relying on Solar and Geothermal Energy during Summer and Winter

Cited by 11 publications

References 34 publications

Effect of Evaporator Position on Heat Pump Assisted Solid Desiccant Cooling Systems

Effect of Evaporator Position on Heat Pump Assisted Solid Desiccant Cooling Systems

Assessment of Ground Regeneration around Borehole Heat Exchangers between Heating Seasons in Cold Climates: A Case Study in Bialystok (NE, Poland)

Evaluation of Coupling PV and Air Conditioning vs. Solar Cooling Systems—Case Study from Jordan

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