Master of Science in Building Services Engineering

Permanent URI for this collectionhttp://192.248.9.226/handle/123/12432

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Browsing Master of Science in Building Services Engineering by Author "Lekamwasam, S"

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    item: Thesis-Abstract
    Condensate recovery from air handling units and fan coil units to reduce the water consumption by the air conditioning systems
    (2023) Ragulakeethan, S; Wijewardane, MA; Lekamwasam, S
    This study investigates the potential for reduction of makeup water consumption by recovering condensate captured from Air Handling Units (AHUs) and Fan Coil Units (FCUs) of central chilled water system in hot and humid climatic conditions. In conventional air conditioning systems, significant amounts of condensate is generated at different components and typically discharged as waste. The cooling towers are used to enhance the heat rejection efficiency of the condenser of the chilled water systems. Usually, it requires a significant amount of makeup water (2% of nominal flow rate) to replenish the regular water losses, mainly due to the evaporation. Therefore, the condensate collected from the AHUs and FCUs can be routed through the cooling tower, resulting in the reduction of potable water usage and to improve the quality of the cooling tower water. This paper presents a method to collect the condensate water and store it in a holding tank for later use in offsetting the cooling tower makeup water requirement. The analysis was performed by collecting the condensate from AHUs/FCUs of five different types of buildings in three different weather zones in Sri Lanka with varying climatic conditions. The findings demonstrate that condensate recovery can be an effective strategy to reduce the water consumption in central air conditioning systems, especially in regions facing water scarcity or high-water costs. The potential benefits of this approach include decreased water consumption, lower water bills, and a reduced environmental impact and eventually the overall energy consumption of the system. Keywords: Water conservation, Hot and humid climate, Condensate recovery, Makeup water, Central air conditioning system
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    item: Thesis-Abstract
    Potential energy saving with high at chilled water designs compared to the conventional low at design for office buildings
    (2023) Joseph, AI; Wijewardane, A; Lekamwasam, S
    This thesis investigates the potential energy saving benefits associated with high delta T chilled water designs compared to conventional low delta T designs in office buildings. This high delta T requirement specified in the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) 90.1: 2016 under subsection 6.5.4.: “Chilled Water coil selection and theoretical background of temperature difference towards energy efficiency”. The aim of the study is to evaluate the capital cost reduction and annual energy savings achievable through the implementation of high delta T configurations and finally identify the applicability in tropical countries. The study followed a comprehensive research methodology that involved analysing 03 chilled water delta T options and assessing their impact on capital costs and energy consumption. The findings of the study demonstrate a significant cost savings and energy efficiencies associated with high ΔT chilled water designs. A total capital cost reduction of 2.8% for the ΔT=7°C system and 3.6% for the ΔT=8.3°C system was observed compared to the conventional ΔT=5°C system. Additionally, the annual energy analysis revealed a 0.97% reduction in energy costs for the ΔT=7°C system and a higher energy cost saving of 1.93% for the ΔT=8.3°C system compared to the ΔT=5°C system. These findings highlight the potential benefits of adopting high delta T chilled water designs in office buildings. The results not only demonstrate cost-effectiveness but also underscore the importance of energy efficiency and sustainability in building design and operation. The outcomes of this study contribute to the existing body of knowledge in the field and provide valuable insights for building professionals and stakeholders seeking optimal cooling system solutions. By embracing high delta T designs, practitioners can achieve tangible benefits in terms of reduced capital expenditures and ongoing energy consumption, leading to a more sustainable and economically viable built environment. Keywords: Energy efficiency, high delta T, chilled water, office building, tropical country