•Thermal comfort and HVAC energy in open-plan space with multiple AHUs is investigated.•A model predictive control strategy is evaluated on real-world occupancy patterns.•The proposed control, DSP, ...is shown to be better than the conventional PID controller.•Good HVAC energy savings are achieved by accounting for spatial variations in MRT.•Higher energy savings when spatial occupancy information is also used for control.
The effect of spatial variations in mean radiant temperature and occupancy on HVAC energy and occupant thermal comfort is studied in an open-plan office space with multiple AHUs. A predictive control method is proposed that arrives at optimum temperature set-point vector by solving an optimization problem, which minimizes HVAC energy consumption subject to acceptable thermal comfort and adequate outside air intake. The optimum temperature set-point vector is used in a PID controller that modulates the AHU fan speed. The proposed control is evaluated on occupancy traces observed in an open-plan space and compared with static set-points based PID control strategies. Normally PID control operates with a dead-band around the static set-point and the AHU fan speed is adjusted only when return air temperature is outside the dead-band. The proposed control has a dynamic set-point and hence the AHU speeds are adjusted at much finer time steps than the normal control. The occupancy traces are classified into densely and sparsely occupied days. Across all days, the proposed control achieves an average additional savings of 15% over a PID control that assumes uniform spatial occupancy distribution in AHU control and 12% over a PID based strategy that uses actual spatial occupancy information.
This paper presents the design and testing of a wireless sensor system developed using a Microchip PICDEM developer kit to acquire and monitor human heart sounds for phonocardiography applications. ...This system can serve as a cost-effective option to the recent developments in wireless phonocardiography sensors that have primarily focused on Bluetooth technology. This wireless sensor system has been designed and developed in-house using off-the-shelf components and open source software for remote and mobile applications. The small form factor (3.75 cm × 5 cm × 1 cm), high throughput (6,000 Hz data streaming rate), and low cost ($13 per unit for a 1,000 unit batch) of this wireless sensor system make it particularly attractive for phonocardiography and other sensing applications. The experimental results of sensor signal analysis using several signal characterization techniques suggest that this wireless sensor system can capture both fundamental heart sounds (S1 and S2), and is also capable of capturing abnormal heart sounds (S3 and S4) and heart murmurs without aliasing. The results of a denoising application using Wavelet Transform show that the undesirable noises of sensor signals in the surrounding environment can be reduced dramatically. The exercising experiment results also show that this proposed wireless PCG system can capture heart sounds over different heart conditions simulated by varying heart rates of six subjects over a range of 60-180 Hz through exercise testing.
Uncertain demand of power for EVs due to their intermittent arrival time and unknown charging requirement may lead to higher costs of power procurement and scheduling difficulties. EVCS typically ...procure power from one or multiple sources based on the demand estimation. In real-time, there can be prediction errors and EVCS needs to manage the deviation with available power and infrastructure. EVCS can utilize EV flexibility to manage these deviations and can save on the cost of energy required for charging. In this paper, we define EV flexibility as potential for V2V transfer and number of extra parking hours that are required for charging. We propose a fast and efficient approach for real-time management of deviations in demand using a priority rank based on EV flexibility. The approach ensures the required charging of EV before the departure. The proposed approach is compared with two different procurement scenarios: (a) zero risk (procurement from retailer only) and (b) an optimized risk approach (procuring from retailer and market using portfolio optimization). Experiments using real-world data on EV arrivals and electricity markets show that the proposed approach provides approximate monthly savings of up to 11.2% and 5.4% in energy bill with respect to (a) and (b).
•An approach for real time deviation management of EVCS demand is proposed.•It uses priority rank based on EV flexibility.•EV flexibility is a function of V2V potential and utilizing extra parking hours.•The proposed approach ensures fulfillment of required charging before EV departure.•Simulations are performed using real-world data on EV and electricity markets.
Increasing real estate and other infrastructure costs have resulted in the trend of co-working offices where users pay as they use for individual desks. Co-working offices that provide personalized ...comfort need to address users with potentially widely varying thermal comfort preferences. Providing personalized comfort in cabins separated by physical partitions with neighboring thermal zones or open-plan offices with a single actuator has received attention in the literature. In this article, the problem of minimizing user discomfort in open-plan co-working offices with multiple actuators while being cognizant of the energy consumed is considered. Specifically, the decision problems of assigning users to desks based on their thermal preferences and jointly controlling the multiple actuators are addressed. The non-linearities in the underlying thermodynamic constraints and the seating decision together make the problem computationally hard. A two-step heuristic that addresses these issues is presented. First, using a model that accounts for spatio-temporal thermodynamics, a one-time assignment of users to desks is performed that reduces the thermal resistance faced by the HVAC systems to provide the preferred comfort levels. Next, the setpoints are decided for all actuators to jointly minimize user discomfort by optimization and model-predictive control. Further, scalability is addressed by clustering user preferences and the associated HVAC actuators’ setpoints for the cases where a large number of actuators may be present in the room.
In this article, we make a case for using Information Technology (IT) to green building facilities and enumerate the important features that an IT framework should possess towards this end. We ...present ECView -- an IT framework that was developed at Tata Consultancy Services (TCS) to manage the carbon footprint of office buildings. We demonstrate the advantages of employing IT for greening facilities through a case study that uses ECView to green a TCS building.
•A building's energy use consists of weather dependent and independent components.•Proposed methodology disaggregates energy use into these categories using limited data.•The methodology is used in a ...supermarket chain and analyzed various drivers.•Stores with poor performance are identified along with possible causes (design/operational).•Methodology is generic, can be utilized for other building types (retails/hospitals/hotels).
Supermarkets are energy intensive. To optimize their energy consumption, major subcomponents need to be identified through disaggregation. Disaggregation can be challenging in supermarkets due to lack of instrumentation at sufficient resolution, especially in developing economies. Also, the diversity in the space cooling systems across stores adds to the complexity. This paper presents a novel approach to disaggregate store level energy into weather-dependent and weather-independent components using facility energy models. The novelty lies in the fact that the approach does not require sensory minutiae or extensive sub-metering. The approach identifies the key drivers of a supermarket's energy consumption, and also estimates gaps in the performance with possible root causes. A case study on using the proposed approach to analyze 94 stores from a supermarket chain is presented. Key findings include: (i) weather-independent loads can dominate weather-dependent loads. (ii) Refrigeration cases contribute to space cooling too. Cooling requirement of these cases can be more than that of space cooling. (iii) For these reasons, occupancy may not appreciably influence a store's energy consumption. (iv) In the supermarket chain studied, various reasons for poor performance spanning both design and operations were discovered, viz., higher deadloads, oversized HVAC systems, and additional load turn-on hours.
Utility of deploying environment/occupancy sensors in buildings is well studied. However, the settings in the existing works are limited in scope and hence the observations may not be generalizable. ...This paper proposes an approach to quantify the utility of sensing in generic zone setups. The usefulness of sensing temperature and occupancy is quantified in terms of ‘information-utility’ and ‘actuation-utility’. The information-utility is quantified as the minimum number of sensors required to reconstruct the ground truth within a tolerable error; and the actuation-utility is the energy savings due to sensor deployment from a baseline, subject to acceptable occupant comfort. A thermal model based on thermodynamic principles is used to model the zone responses while quantifying the sensing utility.
The approach is evaluated through data from a real-world office building. Key findings include: (1) sensing population accurately requires higher number of sensors than sensing temperature. (2) Under steady-state, maximum actuation-utility of sensing at finer spatial resolutions increases with number of actuators. (3) For a real-world case, the maximum actuation-utility was ∼30%. After accounting for system inertia, the maximum and average actuation-utility of sensing were 22% and 5% respectively. This suggests that frequently occurring occupancy patterns influence the average utility of finer-sensing.
Optimizing Viral Marketing for Demand Response Kandhway, Kundan; Sudarsanam, Depak; Vasan, Arunchandar ...
2019 11th International Conference on Communication Systems & Networks (COMSNETS),
2019-Jan.
Conference Proceeding
Electrical utilities mitigate temporary demand-supply mismatch by offering incentives to their customers to reduce electricity consumption. This is called demand response. While previous literature ...have addressed incentive design for demand response from the utility's perspective to improve their bottomline, they have ignored marketing expenses that consume a significant fraction of budget for a demand response program.In this paper, we optimize the marketing strategy for a residential demand response program by everaging the social network of the customers while also accounting for the electricity reduction potential of the customers. The problem is solved from the utility's perspective. Specifically, the utility has to decide the seed nodes and the value of referral reward for viral marketing given a budget. We propose an efficient solution technique for the problem and demonstrate effectiveness of the proposed technique.
Online energy aware routing in wireless networks is the problem of finding energy efficient routes that maximize the network lifetime without the knowledge of future message flows. To maximize ...network lifetime, the paths for message flows are chosen in such a way that the total energy consumed along the path is minimized while avoiding energy depleted nodes. Finding paths which consume minimum energy and finding paths which do not use energy depleted nodes lead to conflicting objectives. In this paper, we propose two-phased energy aware routing strategies that balance these two conflicting objectives by transforming the routing problem into a multi-metric widest path problem. We find that the proposed approaches outperform the best-known algorithms in the literature. We also demonstrate a simple but insightful relationship between the total energy required along a path and the minimum remaining energy of a node along the path. We further exploit this relationship to show that staying within the solution space of paths with high residual energy
and low total energy provides much improved lifetimes in general.
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