Using Personal Environmental Comfort Systems to Mitigate the Impact of Occupancy Prediction Errors on HVAC Performance

Heating, Ventilation and Air Conditioning (HVAC) consumes a significant fraction of energy in commercial buildings. Hence, the use of optimization techniques to reduce HVAC energy consumption has been widely studied. Model predictive control (MPC) is one state of the art optimization technique for HVAC control which converts the control problem to a sequence of optimization problems, each over a finite time horizon. In a typical MPC, future system state is estimated from a model using predictions of model inputs, such as building occupancy and outside air temperature. Consequently, as prediction accuracy deteriorates, MPC performance--in terms of occupant comfort and building energy use--degrades. In this work, we use a custom-built building thermal simulator to systematically investigate the impact of occupancy prediction errors on occupant comfort and energy consumption. Our analysis shows that in our test building, as occupancy prediction error increases from 5\% to 20\% the performance of an MPC-based HVAC controller becomes worse than that of even a simple static schedule. However, when combined with a personal environmental control (PEC) system, HVAC controllers are considerably more robust to prediction errors. Thus, we quantify the effectiveness of PECs in mitigating the impact of forecast errors on MPC control for HVAC systems.Comment: 21 pages, 13 figure

How internet concepts and technologies can help green and smarten the electrical grid

Several powerful forces are gathering to make fundamental and irrevocable changes to the century-old grid. The next-generation grid, often called the ‘smart grid, ’ will feature distributed energy production, vastly more storage, tens of millions of stochastic renewable-energy sources, and the use of communication technologies both to allow precise match-ing of supply to demand and to incentivize appropriate con-sumer behaviour. These changes will have the effect of re-ducing energy waste and reducing the carbon footprint of the grid, making it ‘smarter ’ and ‘greener. ’ In this po-sition paper, we discuss how the concepts and techniques pioneered by the Internet, the fruit of four decades of re-search in this area, are directly applicable to the design of a smart, green grid. This is because both the Internet and the electrical grid are designed to meet fundamental needs, for information and for energy, respectively, by connecting geographically dispersed suppliers with geographically dis-persed consumers. Keeping this and other similarities (and fundamental differences, as well) in mind, we propose sev-eral specific areas where Internet concepts and technologies can contribute to the development of a smart, green grid. We also describe some areas where the Internet operations can be improved based on the experience gained in the elec-trical grid. We hope that our work will initiate a dialogue between the Internet and the smart grid communities

On the Influence of Jurisdiction on the Profitability of Residential Photovoltaic-Storage Systems : A Multi-National Case Study

Policy makers in many jurisdictions have implemented incentive schemes such as ‘feed-in tariffs’ (FIT) and upfront purchase subsidies to encourage consumers to self-generate parts of their power requirements by solar energy. We quantitatively study the impact of jurisdiction-specific solar radiation profile, the typical residential loads, the cost of system components, the price of grid electricity, and incentive programs on photovoltaic (PV) and storage system profitability in Germany, Ontario, and Austin, Texas. In each jurisdiction, for a range of PV and storage system sizes, we compute the optimal use of the system, and hence the best possible profitability of that system in that jurisdiction over a 20 year life span. This methodology allows us to quantitatively estimate the influence of a jurisdiction on the (best possible) profitability of PV-storage systems. We find that the choice of jurisdiction has significant impact on the profitability of PV-storage systems. We also find that policy makers can use the price of grid electricity as well as upfront subsidies to influence profitability, and therefore adoption

Net-zero solutions and research priorities in the 2020s

Key messages • Technological, societal and nature-based solutions should work together to enable systemic change towards a regenerative society, and to deliver net-zero greenhouse gas (GHG) emissions. • Prioritise research into efficient, low-carbon and carbon-negative solutions for sectors that are difficult to decarbonise; i.e. energy storage, road transport, shipping, aviation and grid infrastructure. • Each solution should be assessed with respect to GHG emissions reductions, energy efficiency and societal implications to provide a basis for developing long-term policies, maximising positive impact of investment and research effort, and guiding industry investors in safe and responsible planning

Why Cell Phones Will Dominate the Future Internet

This paper focuses on packetized data I/O, which includes Voice over IP, and ignores circuit-switched voic

On the efficient implementation of fair queueing

The performance of packet switched data networks is greatly influenced by the queue service disci-pline in routers and switches. In particular, the Fair Queueing discipline [1] has several advantages over the traditional first-come-first-served discipline. This paper studies data structures and algorithms for the effi-cient implementation of Fair Queueing. We present a novel performance evaluation methodology and use it to evaluate the relative merits of several alternate implementations