Abstract
Energy consumption due to cooling and ventilation of buildings has grown significantly within the last two decades, and therefore advancement in cooling technologies has become imperative to maximise energy savings. This work numerically investigates the performance of vapour-compression unitary and centralised cooling systems for high rise buildings using an office case-study in the United Arab Emirates (UAE). Energy modelling, thermal comfort and indoor air quality analyses have been carried out using the Integrated Environmental Simulation Virtual Environment (IES-VE). Using the benchmark system based on fan-coil units, the findings have indicated that attaching a Variable Speed Drive (VSD) fan can reduce the overall energy consumption of the building by 8%, with 20% reduction in the cooling loads. The unitary cooling system operating on variable refrigerant flow principle achieved an energy reduction of approximately 30%; however, this system is not recommended in high-rise buildings as the CO2 concentration obtained is in excess of 3000 ppm, which is considerably higher than ASHRAE standards. It is essential for buildings running in hot climates to incorporate hybrid cooling techniques to relieve the load on conventional active cooling systems.
Highlights
The aim of this study is to investigate a range of hybrid and active building cooling systems for buildings in hot climates in order to recommend the most appropriate cooling technique for reducing the energy consumption, carbon emission and improve the thermal comfort and indoor air quality
The findings showed that the way in which the occupants use the building had a major impact on its performance; educating occupants about energy conservation is a great solution and is more beneficial in terms of cost, implementation and knowledge
REVIEW2 was competitive with the industry benchmarks as it was 0.45%10lower of 20 (Figure kWh/m than the local Emirates Green Building Council (EGBC) guidelines
Summary
Active cooling systems are responsible for consuming 80–85% of the building’s total electricity because of the extremely hot climatic conditions where outdoor temperatures reach up to 50 ◦ C with relative humidity up to 60% during peak summer months [1]. At the same time, these cooling systems have to be resilient against the effects of climate change. The ducted split and packaged air conditioning systems mostly dominate the local market by having 30% of the local market share in UAE. The centralised air conditioning systems account for 25% of the local market share. While district cooling and split units/window AC have similar market share of about 18%. The variable refrigerant flow systems only accounts for 2% of the market share since they are not very common in the local market [3]
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