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Title: Performance assessment of radiant cooling system integrated with desiccant assisted DOAS with solar regeneration

Abstract

The Radiant cooling system integrated with Dedicated Outdoor Air System (DOAS) is a viable substitution for conventional all air system in order to reduce primary energy consumption, as it decouples the cooling and ventilation task. In DOAS major portion of energy is consumed in cooling coil where it dehumidifies the process supply air. This study describes an alternate solution for dehumidification, with the substitution of the desiccant wheel with solar regeneration in place of a chilled water coil based dehumidifier. In this paper, simulations were carried out using EnergyPlus on a reference medium office building to investigate the contribution of solar energy towards the total energy consumption of desiccant assisted DOAS with radiant cooling system. To evaluate the system performance and energy saving potential, desiccant based DOAS is compared with cooling coil assisted DOAS integrated with Radiant cooling system. Simulations were carried out for different solar collector area to evaluate primary energy savings. Results indicate that from 7.4 % to 28.6 % energy saving (according to different collector area) can be achieved due to the solar regeneration in desiccant assisted DOAS, the impact of different solar collector area on potential of energy savings is also described.

Authors:
ORCiD logo [1];  [1];  [1];  [2];  [1]
  1. Malaviya National Inst. of Technology, Jaipur (India)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1376508
Grant/Contract Number:
AC05-00OR22725
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Applied Thermal Engineering
Additional Journal Information:
Journal Volume: 124; Journal Issue: C; Journal ID: ISSN 1359-4311
Publisher:
Elsevier
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING

Citation Formats

Khan, Yasin, Singh, Gaurav, Mathur, Jyotirmay, Bhandari, Mahabir, and Srivastava, Prateek. Performance assessment of radiant cooling system integrated with desiccant assisted DOAS with solar regeneration. United States: N. p., 2017. Web. doi:10.1016/j.applthermaleng.2017.06.052.
Khan, Yasin, Singh, Gaurav, Mathur, Jyotirmay, Bhandari, Mahabir, & Srivastava, Prateek. Performance assessment of radiant cooling system integrated with desiccant assisted DOAS with solar regeneration. United States. doi:10.1016/j.applthermaleng.2017.06.052.
Khan, Yasin, Singh, Gaurav, Mathur, Jyotirmay, Bhandari, Mahabir, and Srivastava, Prateek. 2017. "Performance assessment of radiant cooling system integrated with desiccant assisted DOAS with solar regeneration". United States. doi:10.1016/j.applthermaleng.2017.06.052.
@article{osti_1376508,
title = {Performance assessment of radiant cooling system integrated with desiccant assisted DOAS with solar regeneration},
author = {Khan, Yasin and Singh, Gaurav and Mathur, Jyotirmay and Bhandari, Mahabir and Srivastava, Prateek},
abstractNote = {The Radiant cooling system integrated with Dedicated Outdoor Air System (DOAS) is a viable substitution for conventional all air system in order to reduce primary energy consumption, as it decouples the cooling and ventilation task. In DOAS major portion of energy is consumed in cooling coil where it dehumidifies the process supply air. This study describes an alternate solution for dehumidification, with the substitution of the desiccant wheel with solar regeneration in place of a chilled water coil based dehumidifier. In this paper, simulations were carried out using EnergyPlus on a reference medium office building to investigate the contribution of solar energy towards the total energy consumption of desiccant assisted DOAS with radiant cooling system. To evaluate the system performance and energy saving potential, desiccant based DOAS is compared with cooling coil assisted DOAS integrated with Radiant cooling system. Simulations were carried out for different solar collector area to evaluate primary energy savings. Results indicate that from 7.4 % to 28.6 % energy saving (according to different collector area) can be achieved due to the solar regeneration in desiccant assisted DOAS, the impact of different solar collector area on potential of energy savings is also described.},
doi = {10.1016/j.applthermaleng.2017.06.052},
journal = {Applied Thermal Engineering},
number = C,
volume = 124,
place = {United States},
year = 2017,
month = 6
}

Journal Article:
Free Publicly Available Full Text
This content will become publicly available on June 13, 2018
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Cited by: 1work
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  • In this study, a two-stage solar driven rotary desiccant cooling (TSRDC) system with novel configuration and newly developed silica gel-haloid composite desiccant is proposed aiming to reduce regeneration temperature and to achieve high energy performance. Simulated results show that there also exists an optimal rotation speed for TSRDC system. Compared with one-stage system, it is found that for the similar supply air state, the required regeneration temperature of TSRDC system is lower and for the same regeneration temperature, the cooling capacity of TSRDC is bigger. (author)
  • The paper describes a parametric study developed to estimate the energy savings potential of a radiant cooling system installed in a commercial building in India. The study is based on numerical modeling of a radiant cooling system installed in an Information Technology (IT) office building sited in the composite climate of Hyderabad. To evaluate thermal performance and energy consumption, simulations were carried out using the ANSYS FLUENT and EnergyPlus softwares, respectively. The building model was calibrated using the measured data for the installed radiant system. Then this calibrated model was used to simulate the energy consumption of a building usingmore » a conventional all-air system to determine the proportional energy savings. For proper handling of the latent load, a dedicated outside air system (DOAS) was used as an alternative to Fan Coil Unit (FCU). A comparison of energy consumption calculated that the radiant system was 17.5 % more efficient than a conventional all-air system and that a 30% savings was achieved by using a DOAS system compared with a conventional system. Computational Fluid Dynamics (CFD) simulation was performed to evaluate indoor air quality and thermal comfort. It was found that a radiant system offers more uniform temperatures, as well as a better mean air temperature range, than a conventional system. To further enhance the energy savings in the radiant system, different operational strategies were analyzed based on thermal analysis using EnergyPlus. Lastly, the energy savings achieved in this parametric run were more than 10% compared with a conventional all-air system.« less
  • Performance of a desiccant cooling system was evaluated in the context of combined heat and power (CHP). The baseline system incorporated a desiccant dehumidifier, a heat exchanger, an indirect evaporative cooler, and a direct evaporative cooler. The desiccant unit was regenerated through heat recovery from a gas-fired reciprocating internal combustion engine. The system offered sufficient sensible and latent cooling capacities for a wide range of climatic conditions, while allowing influx of outside air in excess of what is typically required for commercial buildings. Energy and water efficiencies of the desiccant cooling system were also evaluated and compared with those ofmore » a conventional system. The results of parametric assessments revealed the importance of using a heat exchanger for concurrent desiccant post cooling and regeneration air preheating. These functions resulted in enhancement of both the cooling performance and the thermal efficiency, which are essential for fuel utilization improvement. Two approaches for mixing of the return air and outside air were examined, and their impact on the system cooling performance and thermal efficiency was demonstrated. The scope of the parametric analyses also encompassed the impact of improving the indirect evaporative cooling effectiveness on the overall cooling system performance.« less
  • A solar desiccant cooling system was operated at the Solar Energy Applications Laboratory, Colordado State University, throughout the 1986 summer. The system comprises an American Solar King fresh air heating/desiccant evaporative cooling unit, a Sunmaster evacuated tube solar collector, hot water solar storage tank, auxiliary electric boiler, controls, and accessories. The cooling unit is operated in the ventilation mode, fresh air being dried in a rotating desiccant matrix, and cooled by heat exchange and evaporative cooling. Return air is used as a cooling medium in a rotating heat exchange matrix, heated by solar energy in a heat exchange coil, andmore » discarded through the rotating desiccant bed. The solar-driven system provided over 90 percent of the seasonal cooling requirements in an experimental, residence type building at average COP levels of 1.0 and solar collection efficiencies of 50 percent when supplied with solar heated water at temperatures of 50 to 65/sup 0/C. Detailed operating results, including total and average solar cooling provided, coefficients of performance, and overall solar cooling performance ratios are presented.« less