Energy Performance and CO2 Emissions of HVAC Systems in Commercial Buildings

Abstract

Abstract:Energy performance of buildings has attracted much attention among building physicists and engineers worldwide. The effects of building heating; ventilation; and air conditioning (HVAC) systems' design upgrade on the building energy performance are the focus of the current study. The adopted HVAC system consisted of chilled ceiling and chilled beam systems served by a centrifugal water chiller. An energy simulation study was undertaken in accordance with the national Australian built environment rating system-rules for collecting and using data. A three-dimensional simulation study was carried out utilizing the virtual environment-integrated environmental solutions software. Results from the current study have shown the importance of utilizing energy-efficient HVAC systems and HVAC strategies for achieving a high building energy star rating. Recommended strategies in order to achieve the nominated star rating; as predicted by the simulation analysis; were presented. Moreover; the effects of solar radiation inside the building atrium were significant; which cannot be overcome by simply installing a low shading coefficient glazing type at the atrium skylight. In addition to providing chilled ceiling technology; a high efficiency chiller and low energy lighting; it is recommended that the building be well tuned during the commissioning period. The current approach could be extended to accommodate higher energy ratings of commercial buildings at different locations worldwide.

Numerical Simulation of Passive Cooling Beam and Its Optimization to Increase the Cooling Power

“…The movement of air is caused by a change in its density and the resulting temperature changes in the flow. Natural convection flow can be laminar or turbulent, as shown in Figure 1, which shows laminar and turbulent convection off a boundary layer of a vertical plate [3,18]. The cooling performance is dependent on the temperature gradient between the mean temperature of the cooling water and ambient temperature, and especially the geometry, particularly the spacing of the ribs.…”

“…The development of the model is based on 2D flow, as shown in Figure 1. It is based on the momentum Equation ( 16), which is the same as for 2D flow between the layers and the volume expansion factors β [3,17,19,21,22]. Result of simulations comparing the percentage change in power with the change in flow for the temperature drop and the flow at which the cooling power of the convector was measured and the percentage change in cooling power related to the maximum power at flow 0.06 kg/s (Table 1).…”

“…The development of the model is based on 2D flow, as shown in Figure 1. It is based on the momentum Equation (16), which is the same as for 2D flow between the layers and the volume expansion factors β [3,17,19,21,22].…”

“…An optimal temperature of 22 ± 2 • C is assumed for our Central European climate for a normally dressed, seated person who does not perform any physical work. The use of ceiling cooling convectors not only ensures optimal thermal comfort, but also contributes to reducing the energy use of buildings [3].…”

Urban Geometry Optimization to Mitigate Climate Change: Towards Energy-Efficient Buildings

“…According to the National Institute for Public Health and the Environment in the Netherlands, if fossil fuel-generated energy still accounts for around 75% of all cooling emissions, these coolant leaks could cumulatively increase the warming impact of CO 2 emissions by up to 25% by the middle of the century [6]. Previous studies indicate that new buildings have shown that carbon emissions can be lowered by more than 50% compared to buildings constructed 5-10 years ago [7,8]. The Intergovernmental Panel on Climate Change urges all responsible persons to promote their country's mitigation strategies [9,10].…”