The Influence of Humidity on Electron Transport Parameters and Insulation Performance of Air

The environmental conditions affect the external insulation performance of power equipment. In order to study the physical characteristics of air discharge, the microscopic process of electron–molecule collision in the air based on the Boltzmann equation has been studied in this paper. The influence of humidity on the air gap insulation performance was also analyzed. The calculation results show that with the temperature 300 K and the pressure 1.0 atm, the electron energy distribution function and electron transport parameters varied with the air relative humidity. As the air relative humidity is increased by each 30%, the average electron energy decreases by about 0.2 eV, the reduced electron mobility decreases by about 0.25 × 1023 [1/(V·m·s)], the reduced electron diffusion coefficient decreases by about 0.2 × 1024 [1/(m s)], and the effective ionization coefficient decreases by about 4 × 10−24 m2. As the air relative humidity increases from 0% to 60%, the critical breakdown electric field increases by 1.22 kV/cm.

Effect of external thermal insulation layer on the Chinese solar greenhouse microclimate

In order to optimize the heat preservation capacity of Chinese solar greenhouse (CSG) and further reduce energy consumption, we clarified the mechanism of the external thermal insulation layer that affects the microclimate environment of CSG. The most suitable external insulation layer thickness (EILT) of the solar greenhouse envelope structure in high latitude and cold region has been indicated. A three-dimensional mathematical model was developed based on computational fluid dynamics and verified using experimental measurement. The temperature variations, heat variations and economic benefit were analysed. The results indicated that covering the outer surface of the enclosures with a thermal insulation layer could effectively increase the greenhouse temperature by 1.2–4.0°C. The influence degree of the external thermal insulation layer on the greenhouse microclimate was as follows: sidewall (SW) > north wall (NW) > north roof (NR). In high-dimensional and cold areas, covering the outer surface of all enclosures with insulation layer as the suitable solution could raise the greenhouse air temperature maximally. The suitable EILT of each maintenance structure was obtained as follows: NW 80 mm, SW 80 mm, NR 100 mm.

Insulation of historic buildings and case study simulation

The article deals with the historic buildings and their insulation. It is generally known that classical thermal insulation of walls from the outside is not permissible due to the cultural value of historic facades. Compared to external insulation solutions, the implementation of internal insulation is more technically complex and faces several risks. In the article is devoted the chapter which deals with the aim of the application of internal insulation in historic buildings. There are mentioned risks associated with the application of internal insulation, which are related to the thermal-humidity behaviour of the structure. One chapter is devoted to faults that may occur after the application of internal insulation. These disorders have a building-physical character and also affect the hygienic criteria of the building. The larger chapter deals with insulating materials suitable for the purposes of interior insulation of historic buildings. The results of a case study from Dublin and Košice are also presented, where the thermal-humidity behaviour of selected thermal insulation materials was investigated. The results of moisture content and surface temperature before and after application of insulating materials are compared.

Designing with External Wall Insulation at Residential Scale

A comparative energy-based study of design with external insulation

Designing with External Wall Insulation at Residential Scale

A comparative energy-based study of design with external insulation