Impacts of humidification process on indoor thermal comfort and air quality using portable ultrasonic humidifier

This paper presents a case study to compare the zone-level actual supplied ventilation rate with minimum required ventilation rate for a typical variable air volume (VAV) operation. The minimum required ventilation rate was computed using zone-level actual occupancy, plug and lighting load data. Two different algorithms were adopted to collect the actual zone-level occupancy information using camera-based technology which are (a) area-based occupancy counting and (b) row-based occupancy counting. Similarly, zone-level Plug, lighting and air-conditioning and mechanical ventilation (ACMV) system-related energy data were taken from the energy submeters and BTU meters. The median values of actual supplied ventilation rates are 0.16, 0.14, 0.14 and 0.12 m3/s for the classroom, computer room, open office and closed office, respectively. For the same zone, the computed minimum required ventilation rates are 0.10, 0.09, 0.10 and 0.08 m3/s, respectively. This case study shows that except during evening classes in classroom and computer room, the actual ventilation supplied is much more than the minimum required ventilation. These over and under ventilation scenarios have been identified as an indicator for energy wastage and poor indoor environmental quality, respectively.

Section: Vav Systemmentioning

confidence: 99%

“…Once OA% was obtained, actual ventilation rates for individual zones at various cooling load (S OA ) was calculated using equation (9).…”

Section: Identification Of External Heat Gain For Individual Zonesmentioning

confidence: 99%

See 1 more Smart Citation

Computation of zone-level ventilation requirement based on actual occupancy, plug and lighting load information

Anand

Cheong

Sekhar

2019

“…Humidity control is of great importance for the indoor and built environment due to its profound impact on thermal comfort 1–3 and living conditions. 4,5 The conventional dehumidification process is different to the vapour compression refrigeration that require the cooling of below the dew point temperature.…”

Section: Introductionmentioning

confidence: 99%

Determination of cost-efficient cooling power range for improving the performance of internally cooled ultrasonic atomization liquid desiccant dehumidifiers

Yang

Chen

Tao

et al. 2020

Liquid desiccant dehumidifiers (LDDs) can be improved by adding internal cooling. However, the addition of excessive cooling power may deteriorate the system‘s cost-efficiency, whereas the addition of insufficient cooling power leads to negligible performance improvements. The objective of this study is to determine the suitable cost-efficient cooling power range for improving the performance of internally cooled LDDs (IC-LDDs). A novel method and a set of criteria related to the moisture removal rate, cooling-power efficiency ( ηc) and coefficient of dehumidification performance from cooling power ( DCOPcooling) were proposed to determine cost-efficient cooling power. The internally cooled ultrasonic atomization liquid desiccant system (IC-UADS), together with a well-validated model based on the conservation laws of mass and energy and the sensible heat balance, was adopted to demonstrate the analysis. The results showed that, although the dehumidification performance improves with increasing cooling power, the improvement rate decreases, while ηcand DCOPcoolingdecline quickly (by 87.9%). For cost-efficient improvement, the necessary power proportion of internal cooling to the system‘s target dehumidification capacity tends to be stable, which was about 29% for the IC-UADS, and independent of the operating conditions. The results may help to determine the reasonable cooling power range for cost-efficient improvement of IC-LDDs.

“…10 The airflow pattern, which plays a great role in indoor hot and humid environment and air quality, is affected by the indoor vent shape, location, quantity, inlet velocity, temperature and other parameters, the geometric size of the air conditioning room and a variety of heat source disturbances, etc. 11–15 Inlets design is critical to the success of the ventilation system, such as size and placement. Studies showed that poor air quality caused by improper indoor air distribution accounts for about 45% of the total number of poor air quality.…”

Section: Introductionmentioning

confidence: 99%

The effect of vent inlet aspect ratio and its location on ventilation efficiency

Chen

Feng

Cao

2019

Self Cite

The total energy consumption of buildings in China has been increasing year by year, ventilation energy consumption accounts for more than 20% of the total building energy consumption. The optimisation of ventilation system design aiming at energy conservation is of great significance while keeping healthy indoor air quality. However, the current codes and standards are still lacking specification requirements for vents design, e.g. inlet size ratio or position, which can greatly impact on indoor airflow and ventilation efficiency. In this work, we investigated the aspect ratios of vent inlets and their locations on indoor air quality. Both experimental and numerical simulation methods were adopted. Ventilation efficiency is represented with the local average peak concentration 〈C ̅*〉A,max. Results showed that when vent inlet is in symmetric conditions (i.e. located in the middle of the sidewall) and the aspect ratio between the length and width of the vent inlet equals to 4, ventilation removal efficiency showed the best performance. These findings are of great importance to the engineering applicability and able to provide reference for future design standards.