Multi tank model for energy efficient rain water harvesting

Rain Water Harvesting (RWH) to supplement service water is an important aspect of sustainable development. As such, much research has been carried out on optimizing the system components of RWH systems so that a maximum water saving efficiency (WSE) can be reached with a minimum storage capacity, enabling the outlay on capital minimized. However, if RWH is to proliferate it should be able to operate in par with centralized service water, supplying collected rain water to user points reliably. This is usually achieved by pumping the collected rain water to service points utilizing electricity, which in fact could negate the positive gains of RWH with regard to principles of sustainability. By introducing a multi tank model, where a smaller tank is installed for each floor at its roof level in addition to the main storage tank, a solution can be reached with superior system performance. In the model, the roof collection enters the top most tank first and then cascades through multiple tanks in multi story situations, before being collected in the main storage tank, vastly improving the overall energy efficiency of the system. The model, not only addresses the space and structural issues of the building but also ensures that the aesthetics of the building envelop is not disturbed due to smaller sizes of the upper tanks

Use of rainfall data to calculate incident solar radiation in Tropical countries

Determining the incident solar radiation for a given location is an important aspect of any solar related application. Though solar radiation data are available at weather stations, localized nature of solar radiation due to topographic and climatic parameters demands measured or calculated solar radiation values for a given location for accurate results. Many correlations have been developed over the past few decades yielding solar radiation values from various weather parameters such as daily sunshine duration, ambient temperature difference, relative humidity, cloud cover etc. However, most of the weather data are practically difficult and costly to record hence requiring a simplistic approach to the issue. For any geographical location the cloud cover plays a major role in controlling the incident solar radiation. In tropical countries, where the climate is highly humid, cloud cover is closely related to rainfall. Therefore, day time rainfall data can be taken as representative of overcast and clear days, paving the way to calculate the clearness index, KT using equations developed on cloud cover data

Development of solar powered pumping for the integration of rainwater harvested in multistory houses

Rain water Harvesting (RWH) is an ancient civil practice for more than 4000 years, drawing attention among scientists in recent decades in the light of potable water shortages and water based natural disasters such as draughts and flash floods. It is observed that the domestic service water (SW) usage patterns are uniform for a given scenario, where over 30% of drinking quality water being consumed for non potable uses such as we flushing, for which harvested rain water (RW) could be used. Roof Top Rain Water Harvesting Systems (RTRWHS) suitable for domestic situations are not being widely used due to non-optimizing of the system's highest cost component, the storage facility or the tank. Extensive research has produced a set of generic curves for Water Saving Efficiency (WSE) of a RTRWHS, enabling the selection of an optimum tank size for a given demand. Validation of this for Sri Lanka could provide a valuable design tool. This was undertaken using a prototype where the daily rainfall data was used with selected usages to create a substantial number of data points, which satisfy the generic curves. These data has indicated that the generic curves can be used in Sri Lanka with generally used roof types such as cement fibre and calicut tiles. In multi-story situations energy is needed for pumping collected rain water to end user points. A strategy should be developed to provide an alternative energy solution to mitigate the strain of extra energy consumption to the national power grid and the resultant Green House Gas (GHG) emissions for RWH to be a true component of sustainable development. Sri Lanka being a tropical country, solar power option is pursued as the most desirable alternative energy source. Since solar power also has high capital cost, minimization of energy used while relying on gravity systems also have been actively pursued. Identifying the suitability of positive displacement pumps over centrifugal pumps when connected to photo voltaic power source, a viable and cost effective solar pumping system is proposed to be used as an integrated draw-off device for a potential RWH system to be used in domestic situationsRain water Harvesting (RWH) is an ancient civil practice for more than 4000 years, drawing attention among scientists in recent decades in the light of potable water shortages and water based natural disasters such as draughts and flash floods. It is observed that the domestic service water (SW) usage patterns are uniform for a given scenario, where over 30% of drinking quality water being consumed for non potable uses such as we flushing, for which harvested rain water (RW) could be used. Roof Top Rain Water Harvesting Systems (RTRWHS) suitable for domestic situations are not being widely used due to non-optimizing of the system's highest cost component, the storage facility or the tank. Extensive research has produced a set of generic curves for Water Saving Efficiency (WSE) of a RTRWHS, enabling the selection of an optimum tank size for a given demand. Validation of this for Sri Lanka could provide a valuable design tool. This was undertaken using a prototype where the daily rainfall data was used with selected usages to create a substantial number of data points, which satisfy the generic curves. These data has indicated that the generic curves can be used in Sri Lanka with generally used roof types such as cement fibre and calicut tiles. In multi-story situations energy is needed for pumping collected rain water to end user points. A strategy should be developed to provide an alternative energy solution to mitigate the strain of extra energy consumption to the national power grid and the resultant Green House Gas (GHG) emissions for RWH to be a true component of sustainable development. Sri Lanka being a tropical country, solar power option is pursued as the most desirable alternative energy source. Since solar power also has high capital cost, minimization of energy used while relying on gravity systems also have been actively pursued. Identifying the suitability of positive displacement pumps over centrifugal pumps when connected to photo voltaic power source, a viable and cost effective solar pumping system is proposed to be used as an integrated draw-off device for a potential RWH system to be used in domestic situation

Development of an optimized integrated rainwater harvesting model for multistorey houses

Rain Water Harvesting (RWH) is an ancient civil practice of more than 4000 years, drawing attention among scientists in recent decades, in the light of potable water shortages and water based natural disasters such as draughts and flash floods. It is noted that much focus has been on optimizing the sizes and operation of individual components, in relation to increased Water Saving Efficiency (WSE), in order to minimize he overall capital investment. However, if RWH is to proliferate, it should function on par with centralized service water supply, particularly in delivering water to service points reliably. This is most relevant in urban, multi story scenarios, where not only service reliability but optimized utilization of space and aesthetic aspects is also important. Taking in to consideration that pumping of collected rain water is energy consuming and therefore against the principles of sustainability, a Cascading Multi Tank Rain Water Harvesting (CMTRWH) system is introduced for multi story situations, where the energy requirement on pumping is much less compared to the conventional models. Even though the CMTRWH model is energy efficient, unless an alternative, renewable power source is introduced to operate an efficient pump with total reliability, the system will have to depend on costly grid power, not only negating the positive impact of using RWH on sustainable development, but also depriving water security to vast communities of people without access to grid power. Sri Lanka being a tropical country, solar power option is pursued as the most desirable alternative energy source. Acknowledging the importance of a storage battery for the reliable operation of the power supply system, sizing curves are developed to select optimally matching pair of PV generator and battery for a given load, at a given location. In order to overcome the difficulty of obtaining measured incident solar radiation at remote locations, a methodology is developed to calculate solar radiation using easily obtainable rainfall data. Key Words: Cascading, Rainwater, Multi-Tank, Harvesting, Stand-Alone, Photo-Voltai

Enhancing the lateral performance of modular buildings through innovative inter-modular connections

Steel modular constructions involve the manufacture of fully equipped three-dimensional prefabricated modules in factory-controlled settings which are then transported to construction sites and assembled to form a complete structure. Adjacent modules are attached to each other only at their corners at inter-modular connections. Typical inter-modular connections are incapable of providing resistance against lateral dynamics loads. Current research shows that under lateral dynamic loads, steel modular buildings with rigid unyielding connectors are vulnerable to failure of the columns which result in either partial or complete collapse of the structure. Modular systems would therefore require additional in-situ lateral load resisting systems, such as shear cores, which would devalue the benefits of purely modular construction as they would need to be built in-situ. To address this shortcoming, this research proposes a novel steel inter-modular connection, with two variations, to achieve safe, reliable and ductile dynamic performance of a modular building under seismic actions. An extensive experimental program was undertaken to study the feasibility of the strength hierarchy and expected ductile failure patterns of the newly proposed inter-modular connections under monotonic and cyclic lateral loads. The experimental study revealed that the proposed inter-modular connections display superior dynamic behaviour with respect to response parameters such as moment-carrying capacity, energy dissipation and ductility. Ductile failure patterns within the connection region and away from the columns, which are critical members, were observed. This information will contribute to the design of safe and efficient inter-modular connections and enable enhanced lateral performance of steel modular buildings under dynamic loads. A comprehensive numerical model of the connection was also developed and validated for use in future parametric studies.</p

A Multi-Point Identification Approach for the Recognition of Individual Leopards (Panthera pardus kotiya)

Visual leopard identifications performed with camera traps using the capture&ndash;recapture method only consider areas of the skin that are visible to the equipment. The method presented here considered the spot or rosette formations of either the two flanks or the face, and the captured images were then compared and matched with available photographs. Leopards were classified as new individuals if no matches were found in the existing set of photos. It was previously assumed that an individual leopard&rsquo;s spot or rosette pattern would not change. We established that the spot and rosette patterns change over time and that these changes are the result of injuries in certain cases. When compared to the original patterns, the number of spots may be lost or reduced, and some spots or patterns may change in terms of their prominence, shape, and size. We called these changes &ldquo;obliterate changes&rdquo; and &ldquo;rejig changes&rdquo;, respectively. The implementation of an earlier method resulted in a duplication of leopard counts, achieving an error rate of more than 15% in the population at Yala National Park. The same leopard could be misidentified and counted multiple times, causing overestimated populations. To address this issue, we created a new two-step methodology for identifying Sri Lankan leopards. The multi-point identification method requires the evaluation of at least 9&ndash;10 spot areas before a leopard can be identified. Moreover, the minimum leopard population at the YNP 1 comprises at least 77 leopards and has a density of 0.5461 leopards per km2