Browsing by Author "Athukorala, N"

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item: Conference-Full-text
Feasibility study on absorption cooling based thermal energy storage
(2013-11-09) Athukorala, N; Sarathchandra, PD; Chiu, J
Human needs are unlimited, but resources that fulfil human needs are limited. Because of this reason, consideration of sustainability in utilization of energy is of immense importance. In this view, use of renewable energy, reduction of energy usage, and reduction/ elimination of use of fossil fuels are encouraged. Space cooling has the highest share (40% to 60%) from total energy consumption and there is an increasing demand of this share in the building sector. Hot and humid climate prominently prevails in the city Colombo, Sri Lanka. On the other hand Sri Lanka experiences a considerable increase of energy demand and electricity tariff rates annually, and these increases have significant impact on the economy. Therefore the need for finding energy efficient, renewable and cost effective solutions is inevitable. Accordingly, a study was carried out to conduct a techno-economic feasibility on thermal energy storage integrated heat driven cooling. Thermal energy storages and absorption chillers are commercially available and have the measure towards sustainability. It was found that most common air conditioning applications among several others are in office buildings, and therefore the main focus of this study is on a typical office building in Colombo city. The result of the study can generalized and applied to other office buildings in the city.Trace700 software tool was used to model and to simulate different system alternatives and to investigate techno-economic performances. Results shows that cool thermal storage integrated thermally driven absorption chiller has a significant energy and cost saving potential, furthermore biogas is proven to be a sound energy source thermal energy supply for the chiller, all aiming for sustainable future. The model developed may be extended to the different climatic conditions and cost structures.
item: Conference-Abstract
Thermal assessment of terrace houses constructed with light weight EPS based panels
(Department of Civil Engineering, University of Moratuwa, 2021-11) Kathiravelu, R; Athukorala, N; Jayasinghe, MTR; Hettiarachchi, P
Terrace houses are used in many countries as a solution for the scarcity of land due to the ability to complete houses with smaller footprint and hence generally tend to reduce the cost incurred. However, there are drawbacks in the terrace houses in tropical climatic conditions due to restrictions on providing thermal comfort. Newly introduced lightweight Expanded Polystyrene (EPS) based lightweight concrete wall panel has less self-weight and less thermal conductivity and absorbs less heat to minimize this effect. This detailed study was carried out to assess the applicability of EPS based lightweight concrete wall panels as the wall material of terrace houses with proper passive design in order to enhance the indoor thermal comfort. Three storey terrace houses have been developed to comply with the locally adopted building regulations. These houses have been assessed with the aid of computer simulations carried out using the DesignBuilder software using the climatic data pertaining to different climates. Comparative studies have been conducted to determine the thermal behaviour of the terrace house by modifying various factors in six ways. Such as materials, thickness, climatic condition, orientation of house cluster, floors and courtyard formations. As an outcome of these detailed studies a set of ideas and rules were developed for improvement in internal temperature. In the first comparative study EPS based concrete has a minimum annual average indoor temperature ranging between 28° – 29°C which is nearly 2% less than concrete walls. Considering the thickness of EPS based walls, 150 mm thickness has a lower temperature value for each day. In the next comparative study, the orientation of the terrace house was compared for summer days. It is recommended that the row of houses should face either South or North to reduce the annual temperature to 28°C. By this, heat transfer into the house through glazing can be reduced. The fifth comparative study suggested that three storey buildings than one storey buildings should be built. The temperature can be reduced by 3-6% at lower floors than 3rd floor by avoiding overheating. The presence of courtyard is more welcome in terrace house to obtain natural ventilation and lighting. However, this may increase the overall temperature of houses under the influence of high solar radiation. In the final comparative study houses compared with various sizes of courtyards. Having small courtyards or covered courtyards may reduce these effects up to 29°C from 32°C. From the comparative studies carried out, the potential of using the lightweight EPS wall panels as load-bearing walls for three-storey terrace houses are shown as acceptable with respect to thermal comfortable in both tropical lowlands and uplands by using proper passive concepts.