A Study and Proposal for Applying Cooling Effect of Hybrid Ventilation to the Monthly Energy Demand Calculation Method in Korea

Countries around the world develop and use software based on the monthly calculation method of DIN V 18599:2007 and EN ISO13790 for building energy performance evaluations. The purpose of this study is to propose a method that can consider the effect of reducing cooling energy demand by hybrid ventilation outdoor air cooling in monthly calculation method-based software. For ventilation simulation, some representative floor plans and area types of Korean residential buildings were established through literature research. A number of dynamic energy simulations were performed for various building orientations, heights, and opening factors. Based on the simulation results, a nomograph that can calculate the cooling energy demand reduction factor according to hybrid ventilation that can be applied to the ventilation heat transfer coefficient is proposed.

Development of an Energy­Efficient Microclimate System for Dairy Herd Loose Keeping

The authors studied the scientific and technical literature regarding the microclimate influence on dairy cattle productivity. It was found out that the building microclimate parameter deviation from certain limit values reduces milk yield by 10-20 percent decrease the live weight gain by 20-30 percent increases the mortality of young animals by 5-40 percent and reduces the number of lactations by 15-20 percent for the herd. (Research purpose) To conduct a survey of modern microclimate systems and their technical implementation for livestock buildings, suggesting the best option while reducing energy costs. (Materials and methods) A classification scheme was provided for microclimate systems. The factors affecting the microclimate of livestock premises were presented in one figure. The main functions of ventilation systems in animal husbandry were identified. The conditions for the use of natural and forced (tunnel) ventilation systems were described. The devices for changing the microclimate on the premises were presented. The possibility of using an overlapped ridge in the area of the roof ridge was considered to catch the airflow and minimize moisture penetration. (Results and discussion) To decrease energy consumption, it was proposed to shift from a supply ventilation system to a natural and hybrid ventilation system, which contains an air removal system, lighting equipment, heating elements, sensors, fans with spray nozzles, sashes. (Conclusions) It was found out that in summer, natural ventilation is unable to prevent heat stress from cows. It was determined that in case of heat stress within 60 days, losses could amount to 4.2 million rubles. To ensure optimal microclimate conditions and reduce costs from heat stress, it was proposed to use an innovative natural and hybrid ventilation system. The calculations showed that a 60-day energy consumption of the proposed system equals 264 thousand rubles.

Effects of the COVID-19 Pandemic on Indoor Air Quality and Thermal Comfort of Primary Schools in Winter in a Mediterranean Climate

Research studies have shown the potential effects of indoor environmental quality (IEQ) on pupils’ health and academic performance. The COVID-19 pandemic has prompted renewed interest in the assessment of deficient indoor air quality (IAQ) conditions in schools and has become a priority over achieving adequate comfort conditions. Scientific studies confirm aerosols as one of the transmission routes of SARS-CoV-2 so that the possibility of airborne transmission increases in indoor environments with high occupancy, such as classrooms. As a result, international protocols and guidelines have established a requirement for educational buildings to over-ventilate with a fresh outdoor air supply. The main object of this work is to analyse the effects of the COVID-19 pandemic on thermal comfort and indoor air quality, in winter, in two classrooms of southern Spain. Thus, onsite measurements of environmental variables were conducted before and during the pandemic. Both classrooms have mechanical ventilation systems as they are within a recently built primary school (2018). Results shows a decrease of 300 ppm in CO2 weekly average values during the pandemic, when hybrid ventilation is used, and a decrease of 400 ppm when schools are naturally ventilated during all teaching hours. However, the analysis of standards shows that over 60% of hours are thermal discomfort conditions.