The HARint Space: A methodology for compliant elevator traffic designs

Abstract

A previous paper introduced the concept of the HARint plane, which is a tool to visualise the optimality of an elevator design. This paper extends the concept of the HARint plane to the HARint Space where the complete set of user requirements is used to implement a compliant elevator traffic design. In the HARint Space, the full set of user requirements are considered: the passenger arrival rate (AR%), the target interval (int_tar), the target average travelling time (ATT) and the target average waiting time (AWT). The HARint Space provides an automated methodology in the form of a set of well-defined steps that allow the designer to convert these four user requirements into a compliant elevator traffic design. As with the HARint plane method, the target interval is used in combination with the expected arrival rate (AR%) and the building population, U, in order to find an initial assessment of the number of passengers expected to board the elevator. The target average travelling time is then used to select a suitable elevator speed. This is then used to calculate the round trip time and then select the optimum number of elevators. An iteration is then carried out to find the actual number of passengers, and hence the elevator capacity. A check is then carried out to ensure that the target average waiting time has been met, and if not, then a modification of the design is required (usually by increasing the speed or increasing the number of elevators). While the HARint plane provides the optimum number of elevator cars to achieve the two user requirements, the HARint Space provides the optimum rated speed as well as the optimum number of elevators to meet the four user requirements of arrival rate, target interval, target average waiting time and target average travelling time. An obvious consequence of the introduction of the average travelling time as a user requirement is that the speed becomes an outcome of the HARint Space. The method also triggers a zoning recommendation in cases where the average travelling time cannot be met by varying the speed within reasonable limits.

Practical application: The work in this paper presents a methodical procedure allowing the designer to select the number, speed and capacity of a group of elevators in a building in order to meet four user requirements: Arrival rate, target interval, target passenger waiting time and target passenger travelling time. Following this procedure ensures an optimal design. It also provides the user with a graphical method for visualising the optimality of the design.