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Reducing cooling loads in hot countries requires thermal insulation, and cooling methods be improved. Evaporative cooling, although problematic, is one solution that can be explored since it is significantly more efficient than regular compressor air conditioners, and the net result of using one is cooling. Furthermore, while compressor air conditioner efficiency decreases with rising temperatures in summer, evaporative ones, up to a point, are the exact opposite. A novel hybrid cooling system capable of combining both showed an 80% decrease in cooling load. The system's efficacy was assessed in this paper by thermally simulating designs that are suitable for the hot Middle East region. Two locations with different environments and building guidelines that are representative of the variations in the area were selected. The first was the hot, dry Baghdad environment; the other was Dubai's coastal, more humid city. Two different houses were designed to suit the municipal rules of each and accommodate the hybrid cooling system. As expected, the simulation results showed that savings in the dry Baghdad climate were high at 78% compared to a non-insulated alternative. In Dubai, unsurprisingly, they were less at 52% on the more humid coast. Further simulations revealed that this latter figure in the humid coast could also be achieved using good thermal insulation. [ABSTRACT FROM AUTHOR]

The skylight on the roof of an atrium can be popular for commercial malls to illuminate the core area of the building. However, the solar radiation and its heat can get into the building together with the daylight, causing excessive cooling load. This paper studies the daylighting and energy performances of skylight coverage area for the air-conditioned atriums in the hot and humid regions. The energy performance with different atrium heights, glass types and the coverage ratios of the skylight are studied. The daylight performance was simulated by the ray-tracing Radiance and was transferred into EnergyPlus for energy evaluations. The finding suggested that, for hot and humid climates, the skylight coverage ratio should be controlled carefully to prevent the excessive solar heat gain. When the on/off lighting control is applied, the total energy consumption of the single-floor cases (or of the top floor for the multi-floor cases) leveled off when the coverage ratio of the skylight reached 9%. Thus, the skylight is favorable to the energy saving of the low-rise or single-floor commercial buildings only under the current assumptions, as the ground of the atrium cannot be well illuminated while the excessive solar radiation gets into the building. The skylight should be shaded in cooling seasons to prevent the excessive solar heat gains. [ABSTRACT FROM AUTHOR]

Free cooling is sometimes useful to face up not only ventilation load but also cooling load as well, taking advantage, directly or indirectly, of the enthalpy difference between inside and outside air in summer. The paper reports on the analysis of the energetic advantage of direct and indirect evaporative cooling (IEC) techniques conducted in summer in different European climates, in which external air flow is established by outdoor, indoor and inlet air enthalpies comparison. Psychrometric diagram has been divided into seven zones as a function of external air conditions; for each zone outside air flow control logic and obtainable free cooling effect have been developed and evaluated. As a function of indoor conditions, outdoor conditions (expressed hourly by Typical Meteorological Year), inlet temperature, external ventilation air flow and building cooling load, energy savings with free cooling techniques have been calculated, considering water consumptions in the adiabatic saturators. Interaction of free cooling, sensible heat recovery and IEC allows very interesting seasonal cooling load reductions, with the additional advantage of decreasing the chiller cooling capacity. All the energetic advantages have been evaluated by an economic point of view, in terms of net present worth and discounted payback period of the investment. [ABSTRACT FROM PUBLISHER]

An introduction to the journal is presented in which the editor discusses an article on reduction of cooling loads in office building in Great Britain's warm climate, another article on use of alternative energy systems in the Indian construction industry, and an article on interactive tool to assess carbon impact of low-carbon dwellings.

The traditional capillary radiant air conditioning system with water as heat exchange medium in the indoor unit may have defects of water leakage, pipeline freezing in winter and time delay of cooling and heating effect. It can only achieve good cooling or heating comfort, which is related to the installation of radiant capillary or panel in the floor or ceiling. In view of these defects, this work proposes a multi-connected dry capillary radiant (MDCR) air conditioning system with refrigerant as heat exchange medium. For the cooling operation, the fan coil assisted capillary radiant cooling (FCR) is developed. The fan coil bears part of the sensible cooling load to improve cooling effect and undertakes the entire latent cooling load to dehumidify the air to avoid the condensation. Two operation modes including the capillary radiant cooling (CR) and the FCR were comparatively tested. The test results show that the FCR can maintain the indoor temperature at 19–22°C, a comfortable temperature range, and can dehumidify the air to prevent the condensation. The experimental results demonstrate the application feasibility of MDCR for radiant cooling. In addition, the FCR can maintain the comfort relative humidity at 74–80% during the whole process of the refrigeration operation. The thermal comfort indices of predicted mean vote (PMV) and predicted percentage dissatisfied (PPD) can be kept at −0.5 ~ 0.5 and 0–10% at different heights of the indoor room. It can be concluded that FCR can achieve good thermal comfort and the indices of PMV and PPD can reach Class I standard. [ABSTRACT FROM AUTHOR]

Most of the building energy is mainly contributing to the achievement of thermal comfort. The cooling load on air conditioners will increase with increased heat transfer into the building from the surroundings. The amount of heat transfer into the building mainly depends on building materials used in construction. In this research, an attempt has been made to analyse the self-sufficient homes' concept by visualizing variation in heat transfer of the building concerning ordinary clay brick and brick with sinicon composition. The temperature distribution of airflow, time lag, decrement factor, and comfort conditions are investigated concerning these materials with computational fluid dynamics. Numerical modeling has been defined by selecting three-dimensional fluid flow governing equations and the k--ε turbulence model. All the fluid flow governing equations have been solved with the finite-volume second-order upwind discretization and SIMPLE algorithm for pressure--velocity coupling. Numerical results have been analysed for both the materials and we identified that the sinicon brick material for the considered wall thickness (9 inches) had registered an increased time lag (-2 hrs) and a decreased decrement factor (0.05). This research investigation shows that the sinicon-brick wall strongly decreases heat transfer through it compared to the normal-red brick wall. The sinicon brick significantly reduces the air conditioner's cooling load by decreasing heat energy penetration into the building. [ABSTRACT FROM AUTHOR]

Air conditioning is of the most energy saving potential system in the metro station. This study analyzes the composition and characteristics of air conditioning cooling load in a metro station. The hourly distribution and the proportion of each cooling load are calculated. The results show that cooling load fluctuation of metro air conditioning is large, and the operating time of different load varies greatly. According to the air conditioning cooling load, the coefficient of performance of the fixed frequency screw, variable frequency screw, series countercurrent screw and magnetic bearing centrifugal chiller under the load of 20–100% are tested. The annual operating cost of four chillers is compared. Test results show that the magnetic bearing centrifugal chiller has a much higher coefficient of performance at part load and lower annual operating cost. Increased initial investment can be recovered in less than 2 years. The magnetic bearing centrifugal chiller is suitable as a cold source of air conditioning system in the metro station. [ABSTRACT FROM AUTHOR]

Integration of phase change materials (PCM) into building elements is explored extensively in the last decade to reduce air-conditioning demand for indoor thermal comfort. The PCM could absorb and release thermal energy as latent heat in a narrow temperature range. Several experimental studies reported energy saving and indoor temperature drop in summer conditions. However, the matter is sparsely researched in the environment of the United Arab Emirates (UAE), a region of high heat flux throughout the year. The current research provides an overview of the integration of PCM in buildings for indoor thermal comfort and energy saving in the UAE. The research highlights the problems of building-integrated photovoltaics (BIPV), e.g. efficiency drop. The significance of the PCM application in the built environment and its research gap is highlighted by reporting all the previous findings on the topic including the application of PCM in glazing, concrete and BIPV. [ABSTRACT FROM AUTHOR]

Despite the temperate climate, cooling loads in UK non-domestic buildings (specifically offices) have a highly significant effect on the energy use of urban areas. Recent summer heatwaves (as seen in 2005) caused blackouts in areas of London, where the requirement for cooling resulted in an electrical demand that exceeded the capacity. With summer temperatures predicted to rise, this problem is likely to be exacerbated, and the need to mitigate for such a scenario is vital. Passive and low-energy cooling techniques can play an important role in reducing official electrical demands. However, the more fundamental problem relates to the internal heat gains being generated from, in particular, IT equipment and lighting. For a country such as the UK, cooling systems in offices (and other non-domestic buildings) only exist at all due to these gains. Through the use of energy management and technologies that might be available by 2030, internal equipment gains can be reduced such that the requirements on the office cooling system are completely different, and the likelihood of a passively cooled office (or low-carbon office) greatly increased. This study thus proposes an approach for reducing office cooling loads for a UK climate, using a defined exemplar London office building to demonstrate the effect of IT equipment and lighting on cooling for the existing buildings. In addition, the effect of fabric changes and thermal adaptation of occupants (for a warmer future climate) is estimated. Finally, taking a ‘make tight, ventilate right’ approach (i.e. reducing infiltration and using mechanical ventilation appropriately) is looked at with regards to cooling loads and, specifically, the effectiveness of night-time ventilation. [ABSTRACT FROM PUBLISHER]