关键词: 医院门诊室, 气流组织, 污染物浓度, 数值模拟

Abstract:

A lack of ventilation and poor air quality in many buildings not only affect the learning efficiency of indoor occupants, but also cause sick building syndrome and even increase the risk of infectious diseases. As public spaces where health care workers look after patients with a complex mix of people, hospital outpatient clinics are highly crowded and are largely enclosed during consultations, so airflow and air quality requirements should be even more stringent. In order to avoid health problems caused by poor air quality, a reasonable and effective study on indoor airflow and air quality in hospital outpatient clinics is needed to ensure the quality of their indoor air environment. The existing studies on outpatient clinics mainly include the airflow in large spaces in outpatient buildings and the risk of indoor droplet exposure in outpatient clinics, without considering the evaluation of indoor personnel comfort and contaminant removal efficiency. There is a lack of multi-perspective evaluation research on indoor airflow organization, indoor air quality and personnel comfort in outpatient clinics.

Therefore, to improve the comfort and safety of people in hospital outpatient clinics, this paper conducts indoor air quality tests for hospital outpatient clinics, and establishes a ventilation model of outpatient clinics based on the numerical simulation method. It combines the three air supply modes (upper air supply and upper exhaust, upper air supply and lower exhaust, and under floor air supply and upper exhaust) with two exchange times per hour (ACH=3/6 h-1). The effects of six ventilation schemes on the indoor air distribution and contaminant concentration are compared and studied. Draught rate, energy utilization coefficient and contaminant removal efficiency are used for evaluation and analysis. The results show that:

(1) An experimental study of outpatient clinics in a hospital in Taiyuan reveals that the indoor air quality in consultation rooms is poor. All eight consultation rooms measured have a concentration that exceeds the standard (>1 000 ppm) during the consultation period. In seven of the consultation rooms, the time of excessive concentration accounts for more than 50% of the total time of consultation, with the highest percentage reaching 86%.

(2) By increasing the air change per hour, the indoor CO2 concentration can be reduced from the over-standard concentration to less than 1 000 ppm (part per million), and the reduction range is more than 200 ppm.

(3) Under the upper air supply and upper exhaust scheme, the draught rate is lower and the contaminant removal efficiency is higher for the same number of air changes, which is effective in removing pollutants while ensuring the comfort of the occupants. However, the energy utilization coefficient is the lowest, which means some heat is wasted.

(4) The adoption of the upper air supply and lower exhaust scheme helps to improve the personal comfort and the energy utilization coefficient of the air supply. Its draught rate is the lowest and its energy utilization coefficient is the highest under the same ACH. However, it has the lowest contaminant removal efficiency and the highest CO2 concentration at the same height, which does not effectively remove pollutants but leads to a build-up of pollutants.

(5) When the under floor air supply and upper exhaust scheme is used, the contaminant removal efficiency is the highest, with 1.24 and 1.49 for the two types of air change per hour respectively, allowing for efficient removal of contaminants in the exhalation range. However, when the air supply velocity is low, its draught rate is the highest, which affects the personal comfort directly. This phenomenon can be effectively alleviated by increasing the air change per hour.