Methods for traffic and energy analysis of systems for transportation of persons in buildings
Authors: Μάρκος Παναγιώτης 
Published: May 2022

Urbanization has been a life-changing factor during the 20th century and is expected to continue enhanced due to various factors with the most prominent one being the increase of global population. As a result, the technologies pertinent to building design, construction and operation concentrate the attention of scientific community. One of the technologies that are related to the intensification of urbanization is the vertical transportation systems as they permit/favor more than any other technology the construction of tall buildings, increasing that way the land use efficiency. The present thesis presents the research that has been conducted in the field of designing transportation systems for persons in buildings. The purpose of the research was the development of new methods for the traffic analysis and energy consumption calculation of elevator systems and escalators, that can be used for the design of more efficient systems with respect to both the achieved service performance and the energy consumption. The achievement of sufficient service performance is highly important especially in buildings with intense traffic demand (multi-storey office buildings, malls, hospitals etc.); poor performance of transportation systems could cause loss of time, discomfort to building’s population and, finally, loss of building’s value due to low level of its utilization. On other hand, the decrease of energy consumption of electromechanical systems in buildings is a permanent requirement.The thesis comprises of three major parts that correspond to specific topics in which the research was conducted. More specific, in Part A, a complete method is presented for the evaluation of elevator systems’ efficiency with respect to both their service performance and energy consumption. The systems can be in design phase or can be already installed systems. The method incorporates the innovative “Integrated Mathematical Elevator Traffic Analysis” (IMETA) method for the traffic design and analysis of a. modern directional collective, multi-elevator systems that operate under group control that optimizes cost functions and b. directional collective single elevators. The method is the first analytical method that can:•apply for any combination of traffic pattern and demand level, building purpose and architecture and elevator configuration and operation principle (traction & hydraulic), •provide unprecedented operation data (average idling times, number and lengths of response flights, landing call waiting times, numbers of car calls per trip etc.), data for the evaluation of the service performance (landing call and passenger waiting times etc.) and traffic data for a detailed complementary energy analysis of the examined elevator system (average distance of flights, idling times, average load in trips etc.) for the complete operation of the system, as it can analyze reliably every possible combination of passenger traffic pattern and demand level that may be encountered during the operation period,•implement control strategies for “two-buttoned”, directional collective systems,•evolve and generalize the analysis of peak demand periods.The method is analytical, it presents very low computational cost and it produces repeatable results.The IMETA method introduces the novel concept of Unidirectional Trips as the major element of elevator operation. Other elements are the empty-car flights to respond to landing calls and for the redistribution of elevators to strategic floors, as well as the standing-still of free elevators.The elevator system’s operation is analyzed probabilistically in four discrete modules. The first is the “Input Data module” that handles data about: a. the building architectural design, b. the expected occupants’ circulation pattern and transportation demand level and c. specific traffic design variables for the elevator system. Its output is an “initial estimation” for the average operation state of the system. Based on the initial estimation of the average operation state, the “Landing Call Allocation module” describes all the probably available allocation cases for a random landing call in each served floor. Specific parameters are calculated that are relevant the applied control strategy. An important detail is that in “Input Data” and “Landing Call Allocation modules”, specific parameters that are used for the “initial estimation” of the average operation state cannot be calculated analytically because the effect of the application of the control strategy has not been previously assessed. To deal with this issue, when these parameters are encountered for the first time, proper default values are given to them.Next, the “Control Strategy module” processes the output data from “Landing Call Allocation module” and implements the desirable control strategy for the definition of the most suitable of the available allocation cases for a random landing call at each served floor. Any control strategy can be implemented as far as it can be numerically expressed.Finally, the “Output Data module” accepts data from all other modules and calculates the final average state of the elevator system’ operation. It also provides a multitude of output data for the evaluation of the elevator system performance, as well as for a further energy analysis.An iterative procedure that is based on the method of bisection is used for the transition from the estimated initial average state of elevator operation - described in “Input Data” and “Landing Call Allocation modules” - to the calculated, final average state in “Output Data module”. The convergence to the corrected values of all parameters that accept initially default values, signifies the convergence of the method to the calculated average state of elevator system operation.The IMETA method feeds with traffic data a new energy consumption model for traction elevators. The model processes engineering design data with unprecedent detail and granularity for the drive unit and the parallel electrical systems (control circuits, lighting and ventilation in cars etc.) and it features novel routines for: a. the calculation of guiding energy losses, b. the estimation of the energy consumption for door operation and c. the calculation of the effect on the energy consumption of non-compensated suspension elements. The model produces extensive energy data for the executed flights and the stationary operation.The novel “Energy - Service Efficiency Index” IES is proposed for generic implementation in transportation machines. Index IES evaluates the overall efficiency of a transportation machine, considering both its service performance and energy consumption. For any period with specific transportation demand, IES reduces the product of the energy consumption of the system during a specific period with the number/total load of transported passengers/materials in the same period, to the product of the average distance of transportation with the average transportation time. Index IES facilitates the design of transportation systems with high service performance without excessive energy consumption, or from another standpoint of view, the design of more energy efficient transportation systems without significant decrease of the obtained service performance. The index acquires unique value for any transportation system; however it can apply for entire buildings for depicting the complete efficiency of their circulation design.Finally, in Part A, a detailed case study for the design of an elevator system in an office building exemplifies the complete method and the proposed index and demonstrates their usefulness.In Part B, the design of efficient escalators is considered, and a complete method is proposed that correlates specialized traffic analysis and a novel, analytical parametric model for energy consumption calculation. The traffic analysis produces results for the service performance of the escalator as well as traffic data that are fed to the energy consumption calculation model, such as the load distribution on it. The service performance and energy consumption results, along with the produced values of the successfully adapted index IES, permit the complete evaluation of an escalator. The method is implemented in a detailed case study for the design of an escalator in a shopping mall.In Part C, the optimization of the horizontal positioning of elevator systems’ hoistways is attempted for the first time. Two methods are proposed. The first one, the “Optimum Hoistway Positioning Method I” is suitable for a primary stage of architectural design of multi-floor buildings where the various spaces in each floor plan are formed. All floors are partitioned in cells by grids with the same coordinates. Each cell in each floor presents specific x,y coordinates and belongs exclusively to a specific type of space (useful spaces, circulation spaces, atriums, spaces occupied by electromechanical systems, facilities, structural elements, etc.). The “Elevator Usage Intensity Index” is introduced that numerically expresses how often the occupants of a specific area in a usable space may use the elevator system and acquires unique value for each cell that belongs to a useful space. A modified version of the heuristic search method Hill Climbing retrieves the optimum horizontal coordinates that belong to usable spaces or atriums and present the minimum weighted Euclidean distance from all cells of all usable spaces of all floors, considering their “Elevator Usage Intensity Index” values.The second method, the “Optimum Hoistway Positioning Method II” is proposed for a more advanced architectural design stage and – in the present thesis - is applicable for single floor plans. The method considers the complex of circulation spaces and the modified Hill Climbing search method retrieves the optimum horizontal coordinates that are located on the circulation paths and present the minimum weighted Euclidean distance from the entrances of all usable spaces of a floor plan. Then, a modified version of the “Tabu Search” method, being coupled with simple architectural rules that are presented via geometrical constraints and considered structural intrusions, retrieves the sub-optimal coordinates near the optimum ones that belong to usable spaces or atriums and depict the location of the entrance of an appropriately sized and architecturally compatible hoistway.Case studies for the optimum positioning of hoistways in office buildings exemplify both methods.All the proposed methods in the present thesis have been implemented by the author in bespoke computer programs.