Experimental validation of constant efficiency models for the subsystems of an unconventional desiccant-based Air Handling Unit and investigation of its performance

A dedicated outdoor air system (DOAS) can be designed to supply 100% of the outside air and meet the latent load of the room with dry air. The objectives of this study were to develop a model of a DOAS equipped with a desiccant wheel and a vapor-compression refrigeration system, build a prototype, validate the model with experimental data, and gain knowledge about the system operation. The test facility was designed with the desiccant wheel downstream of the cooling coil to take advantage of the operating principles of cooling coils and desiccants. A model of the DOAS was developed in the TRNSYS environment. The root mean standard error (RMSE) was used for model validation by comparing the measured air and refrigerant properties with the corresponding calculated values. The results obtained with the developed model showed that the DOAS was able to maintain an indoor humidity ratio depending on outdoor conditions. Laboratory tests were also used to investigate the effect of changes in the regeneration air temperature and the process airflow rate on the process air humidity ratio at the outlet of the wheel. The results are consistent with the technical literature.

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“…The calculated RMSE for DW and compression refrigeration system variables are consistent with those obtained by other authors [30].…”

Section: Discussionsupporting

confidence: 81%

“…Different models of the desiccant wheel have been developed by many researchers over the years [30][31][32]. In this work, the operation of the desiccant wheel is simulated using the Type 1716 (component of the TESS library), containing a model based on the equations for F1 and F2 potentials developed by Jurinak [33]:…”

Section: Desiccant Wheel Modelmentioning

confidence: 99%

Experimental Validation of the Simulation Model of a DOAS Equipped with a Desiccant Wheel and a Vapor Compression Refrigeration System

2017

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“…The models of the main plant components were described and characterized in detail in previous works [1,32,33].…”

Section: Model and Performance Assessment Methodologymentioning

confidence: 99%

Performance Assessment of a Solar-Assisted Desiccant-Based Air Handling Unit Considering Different Scenarios

et al. 2016

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Abstract:In this paper, three alternative layouts (scenarios) of an innovative solar-assisted hybrid desiccant-based air handling unit (AHU) are investigated through dynamic simulations. Performance is evaluated with respect to a reference system and compared to those of the innovative plant without modifications. For each scenario, different collector types, surfaces and tilt angles are considered. The effect of the solar thermal energy surplus exploitation for other low-temperature uses is also investigated. The first alternative scenario consists of the recovery of the heat rejected by the condenser of the chiller to pre-heat the regeneration air. The second scenario considers the pre-heating of regeneration air with the warmer regeneration air exiting the desiccant wheel (DW). The last scenario provides pre-cooling of the process air before entering the DW. Results reveal that the plants with evacuated solar collectors (SC) can ensure primary energy savings (15%-24%) and avoid equivalent CO 2 emissions (14%-22%), about 10 percentage points more than those with flat-plate collectors, when the solar thermal energy is used only for air conditioning and the collectors have the best tilt angle. If all of the solar thermal energy is considered, the best results with evacuated tube collectors are approximately 73% in terms of primary energy saving, 71% in terms of avoided equivalent CO 2 emissions and a payback period of six years.

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“…The dimensions and thermal insulation characteristics of the opaque and transparent components of the simulated building envelope, the models of the desiccant-based AHU components and of the storage tank can be found in [7,8]. Furthermore, over the whole year, solar collectors provide thermal energy for DHW production, to a nearby user (a multifamily house).…”

Section: The Usermentioning

confidence: 99%

“…• cooling air, cooled by a humidifier (1-7) and then used to pre-cool the process air exiting the desiccant wheel (7)(8).…”

Section: The Test Facilitymentioning

confidence: 99%

Selection of Solar Collectors Technology and Surface for a Desiccant Cooling System based on Energy, Environmental and Economic Analysis

Angrisani

Roselli

Sasso

et al. 2014

Proceedings of 1st International E-Conference on Energies

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Desiccant-based air handling units can achieve reductions in greenhouse gas emissions and energy savings with respect to conventional air conditioning systems. Benefits are maximized when they interact with renewable energy technologies, such as solar collectors. In this work, experimental tests and data derived from scientific and technical literature are used to implement a model of a solar desiccant cooling system, considering three different solar collector technologies (air, flat plate and evacuated collectors). Simulations were then performed to compare the energy, environmental and economic performance of the system with those of a desiccant-based unit in which regeneration thermal energy is supplied by a natural gas boiler, and with a conventional air handling device. The only solution that allows to achieve the economic feasibility of the solar desiccant cooling unit consists of 16 m 2 of evacuated solar collectors. This solution allows to obtain, with respect to the reference system, a reduction of primary energy consumption and of the equivalent CO 2 emissions of 50.2% and 49.8%, respectively, with a pay-back time of 17 years.

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Experimental validation of constant efficiency models for the subsystems of an unconventional desiccant-based Air Handling Unit and investigation of its performance

Cited by 48 publications

References 31 publications

Experimental Validation of the Simulation Model of a DOAS Equipped with a Desiccant Wheel and a Vapor Compression Refrigeration System

Experimental Validation of the Simulation Model of a DOAS Equipped with a Desiccant Wheel and a Vapor Compression Refrigeration System

Performance Assessment of a Solar-Assisted Desiccant-Based Air Handling Unit Considering Different Scenarios

Selection of Solar Collectors Technology and Surface for a Desiccant Cooling System based on Energy, Environmental and Economic Analysis

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