Indoor and Built Environment

In considering total building energy consumption, lighting plays an important role in shaping energy consumption and use. Although key strategies (such as energy efficient lighting products, lighting control systems and energy simulation software) are developed so far, such attempts may be unsuccessful unless users are not taken into consideration. Users’ behaviours and their manual lighting control actions depend on various factors, though within the scope of this study manual lighting control behaviour was analysed only in terms of interior layout and daylight illuminance. Three private offices in Izmir Institute of Technology were monitored using illuminance metres and occupancy/light detectors under eight different interior layout conditions. In relation to change of interior layout and daylight penetrations, users’ manual lighting control behaviours were monitored. The obtained data were then used to construct a fuzzy logic model in MATLAB FIS editor. A fuzzy logic algorithm was applied to classify behaviour patterns about the tendency to turn on the lights. This kind of prediction of the light usage tendency regarding the occupancy is aimed to foresee the ‘possible’ manual lighting control behaviour within given conditions. The gathered classification can be used further in future studies of manual lighting control behaviour and energy-saving estimations/simulations.

Potassium superoxide-based oxygen supply systems demonstrate a tremendous potential for applications associated with mine emergency rescue. In this study, the air revitalization performance of a potassium superoxide plate operating under natural convection conditions was investigated by a series of passive tests in a sealed chamber. Reaction resistance analysis based on experimental data revealed that increasing air temperature and humidity accelerates oxygen generation but reduces the system respiratory quotient as a result of the increased resistance of internal diffusion. Increasing the amount of plates or using them in combination with a carbon dioxide absorption curtain is a practical, effective method for meeting requirements of both oxygen generation rate and system respiratory quotient in underground refuge. Kinetics model that predicted the mean oxygen generation rate, carbon dioxide absorption rate, system respiratory quotient and total thermal output (Q) was also derived from experimental data in this study. Predicted results were found to be in good agreement with experimental data. The proposed model can aid in the design of air revitalization systems used in refuge stations for underground mines.

A study was conducted to assess the concentration of uranium and dissolved radon in drinking water samples collected from Jalandhar district of Punjab, India. The samples were analysed for dissolved radon using scintillation cell method. Laser fluorimetry was used for measurement of uranium concentration. Correlation analysis of radon and uranium concentrations and salinity and total dissolved solids with uranium was carried out. The uranium concentration in water samples varied from a minimum value of 1.53 ± 0.06 mg m⁻³ to 50.2 ± 0.08 mg m⁻³ with a geometric mean value of 14.85 mg m⁻³. The radon concentration in water varied from a minimum value of 0.34 ± 0.07 kBq m⁻³ to a maximum value of 3.84 ± 0.48 kBq m⁻³ with a geometric mean value of 1.46 kBq m⁻³. Ingestion dose to local population, due to radon and uranium in drinking water, for different age categories, was computed and results are being reported in this paper.

This paper reports a computational fluid dynamics simulation of airflow and species dispersion inside street canyons and building blocks simultaneously. Urban thermal boundary flows could cause a profound effect on the dispersion of pollutant scalars and ventilation performance of street canyons. Nominal pollutant concentration differences between the urban street canyon and the countryside fresh air could be determined by a consideration of wind profile and ground vegetation. This study models the interaction of the fluid flow, thermal and pollutant dispersions based on the Reynolds number (Re), Grashof number (Gr) and their combinations – Archimedes number (Ar). The fluid, heat and pollutant dispersion performances were compared with the air, heat and pollutant removal efficiencies, indicated by the air change rate (ACR), heat removal rate (HRR) and pollutant removal rate (PRR). Numerical results indicate that Ar could promote fluid, heat and pollutant removals in street canyons. Transport function lines (contours of heat and mass functions) produced would illustrate the main recirculation developed inside these street canyons studied, to allow development of control strategies for dispersion of heat and pollutant species within these environments. The present work could contribute towards the understanding of the ventilation mechanism in street canyons surrounded by the residential buildings.

This paper aims to derive the operational modes of a parallel double-window system that reduces cooling energy consumption and satisfies indoor comfort through natural ventilation. The parallel double-window system examined in this paper is a window system that could control indoor draft distribution and adjust the size of the opening depending on indoor and outdoor conditions. The system can be used in five ways (all close, out-open + in close, out-open+in open (tilt), out-open+in open (turn) and all open). This work verified the energy savings and indoor comfort of the existing mode experimentally, which were originally derived based on simple calculations at the time when the parallel double-window system was developed. A new operation mode, Alt 1, was derived, which addressed problems of the existing mode. In addition, in this work, the operation mode Alt 2 was derived, which simplified Alt 1 so that the actual occupant can use the system easily. By measuring these three operation modes and comparing the results with those of energy plus simulations, the work derived the amount of cooling energy savings and the level of indoor comfort through the use of an appropriate operation mode during inter-seasonal periods. Compared to when the natural ventilation operation mode was not used, cooling energy consumption was reduced by 60% when the operation mode was in use. The cooling temperature set point could have a significant impact on cooling energy consumption.

The objective of this study was to investigate the effect of children’s daily activity patterns on the size-resolved indoor particles in a pre-school classroom, qualitatively and quantitatively. Real-time particle number size distribution data in conjunction with activity were collected experimentally in a pre-school classroom during two seasons: late spring and early winter. We divided daily activities into six groups: Arrival, Large Group, Small Group, Naptime, Dismissal and Unoccupied. The concentration variation forms of coarse particles were compared qualitatively among activity groups. The results indicated that noteworthy coarse particle concentration variations were observed during each activity group. These variations were caused by four factors: presence/absence of children, variation in the number of children, activity intensity and presence of sources. The emission rates were estimated to quantify the impact of activities. Time series emission rates were deduced from the piecewise-constant inputs and outputs model. The piecewise-constant emission rates were averaged for sequential parts to reduce noise and ensure daily repeated peaks were not missed. The sequential part-constant emission rates were consistent with previously described particle number concentration variation results and the predicted indoor particle number concentration data with sequential part-constant emission rates agreed well with measured data.

There is currently an increasing trend in Europe to build passive houses. In order to reduce the cost of installation, an air-heating system may be an interesting alternative. Heat supplied through ventilation ducts located at the ceiling was studied with computational fluid dynamics technique. The purpose was to illustrate the thermal indoor climate of the building. To validate the performed simulations, measurements were carried out in several rooms of the building. Furthermore, this study investigated if a designed passive house located above the Arctic Circle could fulfil heat requirements for a Swedish passive house standard. Our results show a heat loss factor of 18.8 W/m² floor area and an annual specific energy use of 67.9 kWh/m² floor area, would fulfils the criteria. Validation of simulations through measurements shows good agreement with simulations if the thermal inertia of the building was considered. Calculation of heat losses from a building with a backward weighted moving average outdoor temperature produced correct prediction of the heat losses. To describe the indoor thermal climate correctly, the entire volume needs to be considered, not only one point, which normally is obtained with building simulation software. The supply airflow must carefully be considered to fulfil a good indoor climate.

This paper evaluates the indoor temperature and relative humidity of three construction systems in a Dominican social housing scheme, located in different micro-climates present in the Dominican Republic (DR). For the latter, we used DesignBuilder to model the most common type of social housing (S1). In addition, we have also modelled two other improved construction systems (S2 and S3), which have been the result of two different studies, which were conducted in DR. The simulations were carried out in 10 cities. These cities belong to the following five micro-climates: tropical wet Savanna, tropical wet rainforest, tropical wet jungle, dry semiarid and wet temperate. In this article, we have evaluated the construction systems’ performance in the context of thermal conditions inherent to DR. The latter has been done to verify which of the evaluated construction systems is the most adequate for each micro-climate. For this, we determined the average operating interior temperatures and relative humidities for each construction system. We conclude that Samples S2 and S3 show the lowest temperatures in warm climates, while Sample S1 shows improved performance in colder climates. S1 exhibits the lowest values of relative humidities, followed by S3, while S2 presents the highest values.

Although occupants play a critical role in a building’s energy consumption, their air-conditioning use behaviour is often ignored, with it usually approximated as being a continuous operation. This in turn leads to a large difference between the actual and expected levels of energy consumption, raising the need to study air-conditioning use behaviour of building occupants. In this survey, 3083 questionnaires dealing with air-conditioning use behaviour were received from 34 cities distributed throughout China. The results show occupancy rates of 20% to 75% in residences and around 80% in office buildings during the period of 8:00–18:00. Air-conditioning use behaviour only meets a liveable requirement in residences and reaches a comfortable level in office buildings. This leads to daily air-conditioning operation times of between 0.85 and 4.31 hours in residences, and between 1.67 and 7.22 hours in office buildings, indicating most air-conditioning systems do not run continuously but intermittently, and that the assumption of continuous operation is far removed from reality. Based on these survey results, the large differences between the realistic (intermittent) and assumed (continuous) use of air-conditioning are employed to reveal the weaknesses in the present standards and to examine the optimization of building energy efficiency.