Generating What-If Scenarios for Time Series Data

Time series data has become a ubiquitous and important data source in many application domains. Most companies and organizations strongly rely on this data for critical tasks like decision-making, planning, predictions, and analytics in general. While all these tasks generally focus on actual data representing organization and business processes, it is also desirable to apply them to alternative scenarios in order to prepare for developments that diverge from expectations or assess the robustness of current strategies. When it comes to the construction of such what-if scenarios, existing tools either focus on scalar data or they address highly specific scenarios. In this work, we propose a generally applicable and easy-to-use method for the generation of what-if scenarios on time series data. Our approach extracts descriptive features of a data set and allows the construction of an alternate version by means of filtering and modification of these features

Building Energy Efficiency Assessment of Renewable and Cogeneration Energy Efficiency Technologies for the Canadian High Arctic

Arctic communities, challenged by the harsh climate and a lack of local energy resources, are often confronted with finding more sustainable solutions for power and energy. Due to their isolated nature, reductions in energy or fuel use can have important implications for operating costs, security, and energy independence. While high performance buildings have received significant attention in more populated areas, there has been less work done on the opportunities and challenges for these buildings in the Canadian High Arctic. Providing cost-effective logistical support for researchers in the high Arctic, the Polar Continental Shelf Program has operated a field logistics support hub in Resolute, Nunavut since 1958. With increased demand for logistical support and training over the past decade, the Resolute facility has undergone two significant recent expansions. The facility now contains over 7,400 metres squares of living and working space including the Martin Bergmann Complex (provides accommodations for over 237 people), the Operations Centre (warehouse storage, mechanical shops and offices) and the Dr. Roy “Fritz†Koerner Laboratory. With the increased operational requirements, the facility has seen a significant increase in energy use, greenhouse gas emissions and ultimately utility costs. As such, there is a strong desire to reduce energy use and provide for more sustainable facility operations. As the Polar Continental Shelf Program Resolute facility is fairly energy efficient (1.0 GJ/m²) and well maintained, to achieve deep energy savings it is necessary to examine the impact of more innovative strategies, including the integration of cogeneration and heat pump systems. This paper will present an analysis of different energy efficient technologies and strategies for high performance buildings in the Canadian High Arctic. Thus, a comprehensive energy efficiency analysis is performed using the TRNSYS energy simulation tool. First, detailed energy models of the current facilities are developed and calibrated using monitored data. These energy models then form the base for an analysis of innovative energy efficiency strategies including the integration of onsite cogeneration, cold climate heat pumps, and solar integrated technologies. Each strategy is then examined within a techno-economic framework to determine potential utility cost savings, GHG reductions, and simple payback periods. These results provide an important base for the discussion of future high performance buildings in the Canadian High Arctic

Feature-based Comparison and Generation of Time Series

For more than three decades, researchers have been developping generation methods for the weather, energy, and economic domain. These methods provide generated datasets for reasons like system evaluation and data availability. However, despite the variety of approaches, there is no comparative and cross-domain assessment of generation methods and their expressiveness. We present a similarity measure that analyzes generation methods regarding general time series features. By this means, users can compare generation methods and validate whether a generated dataset is considered similar to a given dataset. Moreover, we propose a feature-based generation method that evolves cross-domain time series datasets. This method outperforms other generation methods regarding the feature-based similarity

Experimental and Analytical Analysis of Perimeter Radiant Heating Panels

In recent years the U. S. and Canada have seen a steady increase in energy consumption. The U. S. in particular uses 25% more energy than it did 20 years ago. With declining natural resources and an increase in fuel costs, it has become important to find methods of reducing energy consumption, in which energy conservation in space heating and cooling has become a widely researched area. One method that has been identified to reduce the energy required for space heating is the use of radiant panels. Radiant panels are beneficial because the temperature set points in a room can be lowered without sacrificing occupant comfort. They have therefore become very popular in the market. Further research, however, is required to optimize the performance of these panels so energy savings can be realized. An analytical model has been developed to predict the panel temperature and heat output for perimeter radiant panel systems with a known inlet temperature and flow rate, based on a flat plate solar collector (RSC) model. As radiative and convective heat transfer coefficients were required to run the model, an analytical analysis of the radiative heat transfer was performed, and a numerical model was developed to predict the convective heat transfer coefficient. Using the conventional radiative heat exchange method assuming a three-surface enclosure, the radiative heat transfer could be determined. Numerically, a correlation was developed to predict the natural convective heat transfer. To validate the analytical model, an experimental analysis was performed on radiant panels. A 4m by 4m by 3m test chamber was constructed in which the surrounding walls and floor were maintained at a constant temperature and the heat output from an installed radiant panel was measured. Two radiant panels were tested; a 0. 61m wide panel with 4 passes and a 0. 61m wide panel with 8 passes. The panels were tested at 5 different inlet water temperatures ranging from 50°C to 100°C. The RSC model panel temperature and heat output predictions were in good agreement with the experimental results. The RSC model followed the same trends as that in the experimental results, and the panel temperature and panel heat output were within experimental uncertainty, concluding that the RSC model is a viable, simple algorithm which could be used to predict panel performance

Techno-Economic Analysis of Heat Pump and Cogeneration Systems for a High Performance Midrise Apartment in the Canadian Climate

With increased awareness on the importance and benefit of energy efficiency, building owners and designers are frequently confronted with the challenge of which mechanical system is most suitable to meet the building’s energy target needs. The decision making process is often aided through the use of building simulation tools; however this type of analysis is often considered costly and time consuming in particular when various mechanical systems need to be assessed. With Natural Resources Canada’s priorities on promoting the sustainability and economic development of Canada’s natural resources, this paper presents an analysis conducted on several standard and innovative mechanical systems to aid decision makers in the early building design stages to select a suitable system. The paper further illustrates the benefits of each system type often not known or misunderstood. Using TRNSYS, five system types are evaluated in a typical newly constructed high performance mid-rise apartment in two Canadian regions: Calgary and Montreal. The five systems selected for comparison include (1) a conventional mid-rise apartment heating and cooling system, (2) boiler/cooling tower water source heat pumps, (3) ground source heat pumps, (4) a cogeneration unit sized to meet the heating load of the building and (5) a cogeneration plus electric driven heat pump system. Heat pumps were selected for the benefit in upgrading and utilizing renewable energy sources and cogeneration for the conversion of natural gas to electricity. The analysis includes a 20 year life cycle cost including a sensitivity analysis on forecasted utility rates

Annual Performance Of A Solar Assisted Heat Pump Using Ice Slurry As A Latent Storage Material

Solar assisted heat pump systems offer an attractive method of reducing the energy used for space heating and cooling, while efficiently using low temperature renewable energy from the sun to reduce the degradation of heat pump performance at low ambient temperatures. However, the majority of these systems use sensible storage to bridge the gap between thermal supply and demand, with the maximum storage capacity limited by physical constraints within the building. Latent storage has the potential to significantly reduce the required tank volumes in these types of systems. Previous work has demonstrated the benefit in heating mode of combining a solar heat pump system with ice based latent thermal storage, with this type of system achieving an up to 86% reduction in space heating energy use compared to a conventional system. The objective of this paper is to expand upon these findings and examine annual system performance in various Canadian climate regions through the evaluation of an innovative new operational mode providing space cooling to the building. The proposed system has distinct heating and cooling modes of operation. In heating mode, energy obtained from the solar collectors is stored in the ice tank. Thermal energy is then extracted from the ice tank using a heat pump, and delivered to a warm water tank acting as the distribution point for heating and DHW loops. An innovative new cooling mode is also presented, where the heat pump is used to build a cold storage reservoir for cooling purposes during the summer months. Excess thermal energy is then dissipated at night using radiative cooling (via solar collectors) or an air cooled condenser. Anticipated system benefits include increased energy storage densities, improved solar collector efficiencies, and potential utility cost savings by operating the heat pump during off-peak hours. To perform the analysis a computer model of the proposed system is developed using the TRNSYS energy simulation program, and integrated into high performance homes in three Canadian regions (Montreal, Toronto, Vancouver). Annual simulation results are presented and compared with typical base case designs in order to assess the viability and potential energy savings. A sensitivity analysis on several system variables is then presented in order to identify key design parameters for improved energy performance

The Potential of Liquid-Based BIPV/T Systems and Ice Storage for High Performance Housing in Canada

ASHRAE Vision 2020 has defined market viable net-zero energy buildings as a key objective for new construction in North America. Designing for this target requires the effective integration of renewable energy systems into the building. However, many buildings have limited roof and façade areas in which to integrate these systems, making it difficult to achieve a net zero energy design. Building Integrated Photovoltaic and Thermal (BIPV/T) offers a potential solution to this issue by converting the building envelope into an active producer of both thermal and electrical energy. Commonly, BIPV/T systems in North America have used air as a working fluid. While this offers easy integration with the building ventilation system, air also has a lower thermal capacitance, reducing thermal energy extracted from a BIPV/T collector. Liquid based systems offer working fluids with higher thermal capacitance, along with the ability to easily integrate with existing thermal storage systems. However, these systems often circulate warm water in order to directly meet heating and hot water loads, resulting in reduced thermal and electrical efficiencies and less durable BIPV/T modules. Circulating cooler water to the collectors can significantly improve both the thermal and electrical efficiencies of liquid based BIPV/T systems. However, the low grade thermal energy collected must then be upgraded for use within the building. This paper examines the potential of using liquid based BIPV/T systems with cool storage and heat pump technologies to meet the thermal demands of a high performance Canadian home. An innovative liquid based BIPV/T system is proposed in which the collector array is connected to a cool storage tank, while a heat pump is used to upgrade and deliver thermal energy to the building. Both sensible and ice-based latent storage options are examined as cool storage possibilities. To perform the analysis, TRNSYS is used to simulate the proposed system integrated into a high performance home in Montreal, Canada. Annual simulation results are presented and compared with typical base case designs. A more detailed temporal analysis of electrical loads is also performed in order to examine the impact of the proposed system on the electricity grid.

X-irradiation of cells on glass slides has a dose doubling impact

Immunofluorescence detection of γH2AX foci is a widely used tool to quantify the induction and repair of DNA double-strand breaks (DSBs) induced by ionising radiation. We observed that X-irradiation of mammalian cells exposed on glass slides induced twofold higher foci numbers compared to irradiation with γ-rays. Here, we show that the excess γH2AX foci after X-irradiation are produced from secondary radiation particles generated from the irradiation of glass slides. Both 120 kV X-rays and 137Cs γ-rays induce ∼20 γH2AX foci per Gy in cells growing on thin (∼2 μm) plastic foils immersed in water. The same yield is obtained following γ-irradiation of cells growing on glass slides. However, 120 kV X-rays produce ∼40 γH2AX foci per Gy in cells growing on glass, twofold greater than obtained using cells irradiated on plastic surfaces. The same increase in γH2AX foci number is obtained if the plastic foil on which the cells are grown is irradiated on a glass slide. Thus, the physical proximity to the glass material and not morphological differences of cells growing on different surfaces accounts for the excess γH2AX foci. The increase in foci number depends on the energy and is considerably smaller for 25 kV relative to 120 kV X-rays, a finding which can be explained by known physical properties of radiation. The kinetics for the loss of foci, which is taken to represent the rate of DSB repair, as well as the Artemis dependent repair fraction, was similar following X- or γ-irradiation, demonstrating that DSBs induced by this range of treatments are repaired in an identical manner

Composition, volume, and aspect ratio dependence of the strain distribution, band lineups and electron effective masses in self-assembled pyramidal In1-xGaxAs/GaAs and SixGe1-x/Si quantum dots

We present a systematic investigation of the strain distribution of self-assembled pyramidal In1-xGaxAs/GaAs and SixGe1-x/Si quantum dots for the case of growth on a (001) substrate. The dependence of the biaxial and hydrostatic components of the strain on the quantum dot volume, aspect ratio, composition, and percentage of alloying x is studied using a method based on a Green's function technique. The dependence of the carriers' confining potentials and the electronic effective mass on the same parameters is then calculated in the framework of eight-band k .p theory. The results for which comparable published data are available are in good agreement with the theoretical values for strain profiles, confining potentials, and electronic effective mass. © 2002 American Institute of Physics

Economic optimization and parametric analysis of large hybrid ground source heat pump systems: A case study

Hybrid ground source heat pump systems offer a solution to reduce initial costs and make systems more economically viable. Their design is however complex and their financial profitability difficult to establish. The design of hybrid system is usually determined by following rough rules and is neither mathematically rigorous nor optimized. In this paper, a methodology recently introduced by the same authors for economic optimization of hybrid ground source heat pump systems is used to carry out a parametric analysis and assess the impact of uncertainty on the optimal design solution. The results show that all the parameters have significant impact on the optimization, and the ground heat exchanger construction costs and ground source heat pump COP had the most impact on the net present value. However trends are difficult to observe because if the non-linear nature of the problem, and thus there is a need for more robust optimization of hybrid GSHP systems under uncertainty