Field Study on Humidification Performance of a Desiccant Air-Conditioning System Combined with a Heat Pump

Kawamoto, Koichi; Cho, Wanghee; Kohno, Hitoshi; Koganei, Makoto; Ooka, Ryozo; Kato, Shinsuke

doi:10.3390/en9020089

Cited by 23 publications

(12 citation statements)

References 30 publications

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“…In cold winter weather, it is recommended the use of humidifiers to increase the RH of the air (that otherwise would be too low with conventional air handling unit practices based on direct heating) [38]. However, the implementation of this technological solution is complicated for retrofitting because of the need for the addition of water storage [134] and requires proper selection, operation and maintenance [38]. In addition, conventional humidifiers (evaporative, spray and steam) are potential sites of accumulation and amplification of microorganisms and odours [11].…”

Section: Ventilationmentioning

confidence: 99%

An overview of solutions for airborne viral transmission reduction related to HVAC systems including liquid desiccant air-scrubbing

Giampieri¹,

Ling‐Chin²,

Ma³

et al. 2021

Preprint

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The world is facing on-going challenges due to the spread of the coronavirus SARS-CoV-2, which is affecting the health of people worldwide and the economy of countries. Social distancing, lockdown and quarantine measures have been implemented globally to limit the spread of the virus with a profound impact on people’s lives. These are interventions which are not considered to be permanent and reproducible in the long-term. As more evidence is growing around the airborne transmission routes of the virus, as previously identified for other viruses such as tuberculosis, measles, influenza and coronaviruses, the role of heating, ventilation and air-conditioning (HVAC) systems in buildings, enclosed spaces and public transport in limiting the transmission of airborne pathogens has become a topic of significant relevance. Although the HVAC strategies recommended by professional engineering associations are capable of minimising the transmission of airborne pathogens, they are also responsible for an increase in energy consumption and possibly in a reduction of thermal comfort for occupants. The objective of the study is to review the role of HVAC in airborne viral transmission, to estimate the energy penalty associated with the implementation of the main HVAC strategies for transmission reduction and understand the potential of liquid desiccant technology as an air scrubber. That is capable to a) energy-efficiently control temperature and humidity in buildings, enclosed spaces and public transport; b) increase the indoor air quality by offering the conditions of temperature and humidity less favourable to the growth, proliferation and infectivity of microorganisms; and c) inactivate pathogens. The main factors involved in the process of the inactivation of viruses or pathogens by liquid desiccant solutions are also described together with possible modifications to the solutions to increase their heat and mass transfer and sanitising characteristics. The study is ended by an economic evaluation of the potential energy benefits resulting from the use of liquid desiccant technology. It is concluded that the technology could be particularly favourable in those buildings where humidity control and/or moisture removal is required or in buildings where viruses are more likely to be present, such as in healthcare facilities/operating rooms, or in the event of an airborne viral outbreak.

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Section: Ventilationmentioning

confidence: 99%

An overview of solutions for airborne viral transmission reduction related to HVAC systems including liquid desiccant air-scrubbing

Giampieri¹,

Ling‐Chin²,

Ma³

et al. 2021

Preprint

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“…( =L,)= ,out and ( =L, )= ,out. Other correlations and thermo-physical properties required to solve the equations are reported in literature [4].…”

Section: Model Descriptionmentioning

confidence: 99%

“…Kawamoto et al [4] experimentally investigated a desiccant based Air Handling Unit (AHU) for humidification purpose during winter period, showing that it is possible to increase the outdoor humidity ratio from 1.8 -2.3 g/kg to 5.8 g/kg.…”

Section: Introductionmentioning

confidence: 99%

Preliminary experimental and numerical analysis of a silica gel packed bed humidification system

2019

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In this research, an innovative air humidification system based on two packed beds made of silica gel spherical particles is developed. Each bed is alternatively crossed by two airflows (regeneration and process). The first air stream, at outdoor conditions, after being heated and humidified through the sorption material, is supplied to the building. The second one, also at outdoor conditions, provides water vapour to the desiccant packed bed. The system design and optimization is carried out through a numerical and experimental approach. The developed phenomenological model is based on the Pseudo Gas-side Controlled (PGC) method, considering only the gas side resistance and, therefore, assuming uniform water content and temperature distribution within the desiccant particles. A test rig to evaluate performance of the packed bed humidification system has been realized and experimental results have been used to validate the model. Obtained performance highlights that the proposed system can provide adequate humidification and that it can be a valid alternative to conventional adiabatic and steam humidifiers.

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“…Silica gel is one of the common adsorbents because of its numerous advantages such as larger pores, larger surface area, and excellent dehumidification capability [1]. In fact, desiccant devices using silica gel as an absorbent have been widely used for dehumidification in many industrial areas [2] in addition to its use in air conditioning systems coupling with a heat source [3][4][5].…”

Section: Introductionmentioning

confidence: 99%

Performance Evaluation of a Desiccant Dehumidifier with a Heat Recovery Unit

Yang

Wang²,

Wu³

et al. 2017

Energies

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Abstract:In order to effectively increase the drying rate and reduce the energy consumption, a dryer which reduces the air humidity at the dryer inlet using desiccant and regenerates the desiccant by recovering waste heat using a heat pipe heat exchanger was developed in this study. Both the adsorption rate and desorption rate of the dryer were measured at several ambient temperatures ranging from 15 • C to 35 • C, relative humidity levels of air ranging from 20% to 85%, and airflow rates ranging from 30 m 3 /h to 150 m 3 /h. The results showed that the adsorption rate in an environment of high relative humidity of air was 4.89 times higher than that of low relative humidity of air at 15 • C. Moreover, the difference in adsorption rate between two given relative humidity of air increased as the ambient temperature decreased. The specific energy consumption estimated with both energy consumption during desorption and the desorption rate indicated that the energy consumption was 8.27 kJ/g H 2 O without using recovered heat, while the energy consumption was 4.77 kJ/g H 2 O using recovered heat at 130 • C.

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Field Study on Humidification Performance of a Desiccant Air-Conditioning System Combined with a Heat Pump

Cited by 23 publications

References 30 publications

An overview of solutions for airborne viral transmission reduction related to HVAC systems including liquid desiccant air-scrubbing

An overview of solutions for airborne viral transmission reduction related to HVAC systems including liquid desiccant air-scrubbing

Preliminary experimental and numerical analysis of a silica gel packed bed humidification system

Performance Evaluation of a Desiccant Dehumidifier with a Heat Recovery Unit

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