Browsing by Author "Rodrigo, S"

Now showing 1 - 4 of 4

item: Conference-Abstract
A critique on on-going retrofit approaches to existing high mass historic building forms with heat sink capacity
Rajapaksha, U; Rodrigo, S; Rajapaksha, I
The research presents a critique on unrealized heat sink capacity of Colombo’s historic British period buildings. The work discusses how on-going inappropriate retrofitting approaches to these buildings can hinder the passive heat sink capacity of high thermal mass envelopes. The research performed field investigations on selected renovated historic high mass buildings of which most of them are naturally ventilated. Results showed that renovated building interiors become overheated during daytime and night time due to direct and indirect heat gain due to newly introduced retrofit interventions i.e. courtyards and windows. Later, one renovated but critical building was simulated with its original status of physical characteristics by removing all newly introduced design interventions using Design-Builder software program. Results show that the original building performs better than renovated building in maintaining indoor air temperatures lower than outside ambient air temperature during daytime. The work illustrates the efficiency of heat sink effect of thermal mass in historic building forms and challenges the on-going retrofit approaches.
item: Conference-Full-text
An investigation of green space within high-rise condominium sites in Sri Lanka
(Department of Architecture, University of Moratuwa, Sri Lanka, 2018-10-05) Jayaweera, N; Rodrigo, S; Nadaraja, J; Rajapaksha, U; Jayasinghe, C; Wijesundara, J; Dayaratne, J
Green spaces in cities have a positive impact on the health of the urban population as well as decrease urban heat Island effects. Therefore, green and open space should not be considered a luxury but an integral part of urban planning.For the purpose of this study a space is considered as a “green space” if the land cover has vegetation. The study investigates the impact of high-density housing developments in the Colombo city and its suburbs on green space. 90% of small Condominium developments (number of units ranging from 15 to 65) and 50% of large condominium developments (over 65 units) had less than 1% of green space on site. The reason for lack of green space was found to be high plot coverage, high FAR, small site extent and no landscape, communal space and green buffer requirement in the current planning and building regulations for condominium developments.
item: Thesis-Abstract
Optimal Utilization of Raio Communication Network in Ceylon Electricity Board: a case study
(2015-02-22) Edirappulige, DRK; Asanka, WD; Rodrigo, S
A very high frequency (VHF) and ultra high frequency (UHF) network is used in Ceylon Electricity Board (CEB) for communication purposes within the company. This network is specially used in the field activities such as in breakdowns & projects. This network is fully owned by the CEB and it is maintained by the company itself. This network is used four bands of frequency called VHF low band (LB), VHF mid band (MB), VHF high band (HB) and UHF band. Also there are four different types of radio equipment in the network called repeaters, fixed sets, mobile sets and hand held sets. Repeater station is used as an amplifier station for long distance communication. Radio sets which are installed in the office places like project offices and customer service centers are called fix sets. Radio sets are installed in vehicles which works in the field are called mobile sets. There were 34 numbers of repeaters, 1000 fixed and mobile sets, 814 hand held sets and 13 other radio equipment at the end of 2010. Presently, this network is not used by most of the uses because of its drawbacks and alternatives. Lots of breakdowns are being reported. It can be a because of an equipment fault, a DC supply fault, a battery fault or an antenna fault. There are several reasons for these breakdowns such as carelessness of uses, oldness of equipment, less knowledge of the network, coverage issues, lightning and corrosion issues. Mobile telephones are widely used as a communication medium in field activities without using existing VHF/UHF network. For the year 2010, around 18.5 million Sri Lankan rupees (LKR) have been expended by the CEB as the operational and maintenance (O&M) cost of VHF and UHF network. When considering the economic benefits of using a mobile operator as an alternative solution to maintain this VHF and UHF network, it is profitable. But non economical benefits of VHF and UHF networks such as broadcast facility, security and fast response are very critical in the power system. So maintaining this network for optimum use is essential. As a first step, all existing drawbacks have to be avoided. There should be a proper maintenance plan and all users have to be educated about the system and its usefulness. Also the network planning system has to be optimized. A network expansion model was derived for future expansions of the network. When this network expansion is used, most of parameters which have to be considered when planning the network can be optimized. They are frequency band, antenna type, transmission power, antenna location and antenna height. Parameters which calculated from this model can be verified using software tools. In addition to that in all installation works, good practices have to be followed to reduce losses and improve the availability of the network. When there is a properly maintain and widely covered network, the communication media within the company will so powerful than before. Then power system reliability will be improved. Finally this will improve the quality of the Sri Lankan power system. However, it is to be studied about the VHF and UHF communication systems before starting this challenging business.
item: Conference-Full-text
Optimizing the fresh-cut flower distribution using the vehicle routing problem for perishable goods
(Sri Lanka Society of Transport and Logistics, 2023-08-26) Rodrigo, S; Kosgoda, KMDL; Thibbotuwawe, A; Fernando, WM; Gunaruwan, TL
Real-world freight distribution problems are complex, primarily because they must adhere to several restrictions on multidimensional vehicle capacity, vehicle characteristics route duration/length restrictions, time windows, and compatibility. As a result, attention must be paid to the distinctive operating procedures and features of various distribution systems. In this context, cut flower distribution is recognized as one of the challenging operations as it requires maintaining a certain level of freshness. Through the entire supply chain (SC), it is vital to keep freshness because it decides the product price, quality as well as customer satisfaction level. We study the fresh flower distribution using data from a reputed floral company in Sri Lanka to find the optimal set of routes for the fresh-cut flower delivery. We employ Capacitated Heterogeneous Fleet Vehicle Routing Problem (VRP) for Perishable Goods with Time Windows and a Single Depot (CHFVRPPGTWSD). Therefore, the main objective of this paper is to minimize the total distribution time while keeping a maximum freshness rate as a KPI to maximize customer satisfaction. We use a hybrid algorithm to fulfill our research objectives. Floral companies would be benefitted from our model as it can assist to identify optimal routes to plan their distribution network with minimum distribution time.