Building Services Engineering Research & Technology

In most industrialized countries, the buildings sector is the largest contributor to energy consumption and associated carbon emissions. These emissions can be reduced by a combination of energy efficiency and the use of building integrated renewables. Additionally, either singularly or as a group, buildings can provide energy network services by timing their use and production of energy. Such grid-aware or grid-responsive buildings have been termed Active Buildings. The recent UK Government investment of £36m in the Active Building Centre is a demonstration that such buildings are of considerable interest. One problem with the concept, however, is that there is no clear definition of Active Buildings, nor a building code to design or research against. Here we develop and test an initial novel code, called ABCode1. It is based on the need to encourage: (i) the minimisation of energy consumption; (ii) building-integrated generation; (iii) the provision of grid services; and (iv) the minimisation of embodied carbon. For grid services, we find that a lack of a precise, quantifiable measure, or definition, of such services means that for the time being, theoretical hours of autonomy of the building is the most reasonable proxy for these services within such a code.

Water-flow window combines the functions of transparent building envelop, solar collector, as well as sun shading. Coloured particles are added to the flowing water within window cavity in order to provide extra shading, prevent indoor glare and enhance solar collection. The energy consumption of both air-conditioning system and water heating device can be further reduced. The aim of present investigation is to predict and analyze the year-round energy performance of a well-insulated water-flow window with different shading control modes. Accordingly, physical model of water-flow window is built up. FORTRAN program is developed and utilized in the numerical simulation.

Results show that water-flow window can achieve exceptional sun blocking and cooling load reduction without occupying extra space. The year-round solar energy collection efficiency is within the range of 17.95∼21.06%. At the same time, indoor heat gain through the window can be reduced by around 50% compared with common double-layer window. The water-flow window under discussion has great application potential in buildings with constant hot water demand and high-density air-conditioning cooling load. In practice, the shading control mode should be carefully decided, and factors including climate region, hot water demand, window size and occupants' preference on indoor light environment should be taken into consideration. Numerical simulation proves to be an efficient method in predicting the energy performance of similar innovative-designed windows and a good assist in decision-making of real projects.

An air curtain is used to ensure an adequate separation between two compartments that is aimed to restrict, a clean one and a contaminated one. The air curtain performance is improved with the use of an air extraction from the “contaminated” compartment. The aerodynamic sealing of an optimized air curtain is assessed regarding particulate matter. The evaluation using visual assessment of the aerodynamic sealing using a cold smoke source is validated against PM 10 detection.

It is shown that the air curtain presents a good aerodynamic sealing for the particulate of PM10 and PM2.5 classes and that the visual assessment method can lead to similar results. An equation was obtained with a view to be used to predict the level of aerodynamic sealing of the air curtain when the exhaust rate becomes too low. Another equation was obtained for predicting the average velocity through the door protected by the air curtain required to obtain an aerodynamic sealing, as a function of the jet parameters (nozzle average velocity and thickness). These test results prove that the air curtain, complemented with an air exhaust from the “contaminated compartment”, is suitable to provide an acceptable aerodynamic sealing for the particulate matter.

Practical application: The findings of this research are applicable when it is necessary to retain the contamination due to particulate matter using a soft boundary, as air plane jets. This is applicable to medical care centres to reduce the possibility of contamination due to bacteria between different compartments or in pharmaceutical process units to avoid cross contamination among them.

This field study was made to study the size of social groups among passengers travelling with lifts. The group size was observed in three types of buildings located in four countries, totally in nine multi-storey buildings. The observations were carried out manually for 12 hours on a normal weekday. Analysis results show that the daily mean group size was generally low: 1.2–1.3 persons in the offices, 1.3–2.0 persons in the hotels and 1.1–1.4 persons in the residential buildings. Hourly means differed significantly from the daily means for each building. This suggests that group size should be considered on hourly or shorter basis. In addition, goodness-of-fit tests were conducted to determine a statistical model for the group size. A geometric distribution was found to fit the data the best across all building types which simplifies modeling of passenger group arrivals in buildings.

Practical application: This article contributes to the understanding of lift passenger tendency to travel in socially connected groups in multi-storey buildings. A unique data set of group size observations around the world is reported on an hourly basis for office, hotel and residential buildings. A geometric distribution is proposed to model the group size statistically, which simplifies the use of socially connected groups when generating passengers in lift traffic simulations. The real-world data and the statistical model of the group size enable more realistic lift traffic simulations that are routinely conducted during the design phase of multi-storey buildings.

Methods of estimating monthly cooling loads in buildings are usually confined to sensible demands only, with latent loads either ignored or added as an arbitrary proportion of sensible cooling demands. This note describes an extension of an existing monthly method for estimating sensible cooling demands that takes account of latent cooling. It reflects the effects of climate, ventilation rate and indoor moisture gains and also of some less widely appreciated impacts of system design. These are illustrated by an example typifying UK office conditions. In order to be workable, the methodology contains a number of simplifications, where precise estimates are needed, and more sophisticated methods should be used.

Practical application: Estimates of annual cooling energy demand made with existing monthly procedures do not account for the size of latent cooling loads or the ways these vary between different forms of air conditioning systems. This note shows how this can be done though, where this is a critical design parameter more complex methods are recommended.

In this study, adaptive branch fan performance in a distributed fan ventilation system was tested. The results demonstrate that the adaptive branch fan stabilises the branch air flow rate within a certain air pressure range corresponding to the branch duct inlet, and this range becomes increasingly narrow as the fan control signal is adjusted to reduce the speed of the fan. The adaptive branch fan is less affected by the main fan and other branch fans in the distributed fan ventilation system because it has a good self-adaptive ability of ventilation duct resistance characteristics and anti-interference ability of the air flow rate. Furthermore, the hydraulic characteristics of the branch fans in the distributed fan ventilation system were analysed. The new performance characterisation parameters and method for modifying the engineering design for the adaptive branch fan were presented.

Practical application: This study investigates the adaptive performance of the branch fan in a distributed fan ventilation system. Our results demonstrate that the new branch fan can stabilise the air flow rate in a mechanical ventilation system. More importantly, we not only propose performance characterisation parameters of the adaptive branch fan that are important for understanding the operation of a mechanical ventilation system, but also present a method of engineering design application. This study can guide the design and operation of mechanical ventilation systems.

Photovoltaic (PV) system efficiency depends on the geographical location and the orientation of the building. Until installing the building structures, the integration of the PV module must be evaluated with ventilation and without ventilation effects. This work optimises the performance of the 250 kWp grid-connected photovoltaic (GPV) for community buildings in the southern part of India. This simulation is carried out to evaluate the system efficiency of the GPV system under various ventilation conditions, such as free-standing PV (FSPV), building integrated photovoltaic ventilated (BIPV_V) and Building Integrated Photovoltaic without ventilation (BIPV). The PVsyst simulation tool is used to simulate and optimise the performance of the system with FSPV, BIPV and BIPV_V for the region of Chennai (13.2789° N, 80.2623° E), Tamilnadu, India. An annual system energy production is 446 MWh, 409 MWh and 428 MWh of FSPV, BIPV and BIPV_V system respectively. while electrical efficiency for the FSPV, BIPV_V, BIPV system is 15.45%. 15.25% and 14.75% respectively.

Practical application : Integrating the grid connected photovoltaic system on the building reduces the energy consumption in the building. The integration of the PV on the roof or semi integrated on the roof is need to be investigated before installing on the buildings. The need for installation of the BIPV with ventilation is explored. This study will assist architects and wider community to design buildings roofs with GPV system which are more aesthetic and account for noise protection and thermal insulation in the region of equatorial climate zones.