PLEA

This paper proposes a new heuristic to simulate and study the visual comfort aspect in the designing of Complex Fenestration Systems. The goal of the heuristic is two-folded, (i) provide useful and simple visualization tools for preliminary glare assessments of indoor spaces, (ii) reduce the computational overhead of extremely expensive annual glare simulations by reducing the number of simulations necessary in the study of glare. The work demonstrates that through a spatial and temporal sampling of annual Vertical Illuminance data it is possible to map the potential glare POVs and to find the critical hours to conduct more detailed simulations. The authors applied the proposed heuristic in a comparative study of 3 different fenestration schemes for 3 annual sky types, a typically overcast (London, UK) and clear sky (Phoenix, AZ, USA), and an intermediate sky (Oakland, CA, USA). In sum, the results of the work show that the proposed heuristic yields a high potential to be used in design procedures that currently are based on expensive glare simulations.

With the aim of reducing carbon emissions and increasing hygrothermal comfort, buildings across the UK are undergoing energy retrofits. With historic buildings, it is important that retrofit actions have a limited negative impact on the building’s fabric and cultural significance. Work to date in the UK has focused on the retrofit of historic solid masonry construction, with little research into the retrofit of historic timber-framed buildings. Changes to these buildings must be managed through the use of established conservation principles. However, where infill panels are beyond repair or have previously been substituted with inappropriate materials, there exists the potential to retrofit a material with a higher thermal performance. Nonetheless, it must be ensured that this retrofit does not create interstitial hygrothermal conditions that could threaten the survival of surrounding historic fabric. In this paper the authors present the hygrothermal simulation and physical monitoring of three different potential replacement infill panels. Results from Glaser calculations, WUFI® Pro and WUFI® 2D are compared to measured results of physical test panels mounted between two climate-controlled chambers. Whilst all three prediction methods successfully identified interstitial condensation where it was measured to occur, major discrepancies existed both between simulated and measured results, and between different simulation methods.

Radiant heating and cooling systems have the potential to save energy and are widely used in zero net energy buildings. Their positive and negative impacts on indoor environmental quality and, in particular, thermal comfort compared to all-air systems are still debated in the literature. This paper presents indoor environmental quality survey results from 3,892 respondents in 60 office buildings located in North America. 34 (2,247 respondents) of these buildings utilized all-air systems and 26 (1,645 respondents) utilized radiant systems as primary conditioning system. Our results indicate that radiant and all-air buildings have equal indoor environmental quality, including acoustic performance, with a tendency towards improved temperature satisfaction in radiant buildings.

A ThermO-Drain (TOD) is a system that uses water cooled by night sky to drain the radiant heat within a building. In office buildings, ‘all air-cooled’ systems are most prevalent. The study aimed to assess the thermal comfort of occupants in a ground and two storied naturally ventilated office building in the composite climate of Nashik in India where TOD system was installed. Assessment was conducted by taking hourly readings over a 25-hour period in peak summer of May 2017. Primary data collected included Dry Bulb Temperature (DBT) and Relative Humidity (RH) indoors, surface temperature of top and bottom of roof slab and Globe temperature within the office. Secondary data for the same period was obtained from the Indian Meteorological Department (IMD). Monthly electricity bills were used to measure the Energy Performance Index (EPI). The Tropical Summer Index (TSI), an index suggested in the National Building Code (NBC) 2016 of India, was calculated. Results show that the indoor operative temperature in the peak of summer with outdoor temperature of 36.30C was found to be close to the neutral temperature of 27.50C. The EPI of 26.5 kwh/m2/year falls within the BEE 5-star rating of below 40 kwh/m2/year.

The multiple criterion scale developed by Hopkinson is extensively utilised to analyse the subjective degree of discomfort due to glare. Using a luminance adjustment procedure, the brightness of a glare source is adjusted to reveal four levels of discomfort, typically: just imperceptible, just acceptable, just uncomfortable, and just intolerable. In many experimental studies, observers are requested to attend to each level of discomfort in ascending order, from the lowest to the highest criterion. There are, however, reasons to believe that assessments made using adjustments might be affected by the initial anchor, i.e. the setting of the variable stimulus before an adjustment is made, and by order effects, this influencing the reported thresholds of discomfort. To investigate anchor bias and order effects, two Hopkinson-like multiple criterion adjustment experiments were performed, respectively with three different initial anchors and three order sequences (ascending, descending, and randomised). The results revealed substantive bias due to anchor and order effects, primarily at lower glare criteria. This demonstrates the need for caution when interpreting subjective evaluations of discomfort due to glare and estimating the robustness of glare indices derived from studies that used models fitted to data obtained with Hopkinson’s multiple criterion scale and luminance adjustment procedure.

There are now more than four million refugees living in camps around the world. The majority of such camps are within inhospitable environments, often with extreme climates. This paper focuses on the thermal conditions of shelters in the Azraq refugee camp (Jordan), subject to an arid climate with high temperatures during the hot season. Due to political and other sensitivities, whole-, or multi-year monitoring of occupied shelters—and hence the empirical determination of overheating—is difficult. Instead, internal conditions in the shelters were monitored for three weeks in summer and used to validate computer models of the accommodation. These models were then used to generate annual predictions of overheating assessed through overheating criteria based on thermal discomfort and physiological indicators of heat stress. Building on these results, the performance of alternative designs specifications or shelter operation strategies were investigated through parametric analysis. The results show maximum indoor temperatures over 45°C. Overheating thresholds were exceeded for more than 20% of the year and physiological indicators suggest the possibility of health-threatening conditions. The use of alternative designs and strategies reduced overheating to nearly 2% of the year, with a steep reduction of severe heat stress indicators.

The increasing complexity of modern architectural geometries emphasizes the need for more accurate simplified calculations of comfort analysis in architectural design. Such computations often require to solve complicated equations, among which the calculation of Mean Radiant Temperature (MRT) is notable. The goal of this paper is to propose a fast reliable technique, named Numerous Vectors (NV), to calculate MRT even in the presence of complex geometries. Considering the area, orientation, and distance of different radiant geometries, the process suggests an innovative method to find the view factor by projecting the surrounding surfaces on a unit sphere as the human body. Rather than separately computing the values of view factors for individual radiant surfaces, the method determines the proportion of the radiation from all surfaces by a single-step process. The NV method can also be used for the calculation of multiple parameters involved in MRT such as solar and atmospheric radiations. The proposed process is much faster than conventional methods available to calculate the view factors and the results are proved to be in a good agreement with analytical data.