Client: Travers Mechanical Services
Location: Albuquerque, NM
Lopez Engineering, Inc. (LEI) provided Electrical design support to Travers Mechanical Services to connect a new chiller and cooling tower to the University of New Mexico Hospital (UNMH) electrical system. According to the Contracting Officer, LEI was the first consulting firm to continually record existing electrical equipment prior to connecting new load to it. LEI recorded current for 72-hours for normal and emergency power equipment branch switchboards, panelboards, and motor control centers in order to determine existing spare capacity. These recordings revealed an existing normal power switchboard and MCC to be overloaded. These recordings also revealed the emergency power equipment branch to have insufficient spare capacity to serve this additional load when using the “N-1” criteria.
As a result of the recording results, chiller service design required connecting to a spare 15 kV outdoor switchgear compartment. From there, a 15 kV feeder extended to a new 1000 kVA, pad-mounted, oil filled, transformer, 12.47 kV-480Y/277V, 3 Ø, 4 W. A feeder was extended from the transformer secondary to a new electrical switchboard, 1600 A, 480Y/277V, 3 Ø, 4 W. This new switchboard then fed a new 1200 A, 480Y/277V, 3 Ø, 4 W motor control center (MCC).
In order to alleviate the overloaded condition of the normal power switchboard, some load was transferred from it to the new switchboard. LEI fed the new chiller, cooling tower, chilled water, and condenser water pumps from this new MCC. This new chiller served all hospital chilled water loads as an integrated part of the chilled water system. In order to alleviate the overloaded condition of the normal power switchboard, some load was transferred from it to the new switchboard. LEI fed the new chiller, cooling tower, chilled water, and condenser water pumps from this new MCC. This new chiller served all hospital chilled water loads as an integrated part of the chilled water system.
Our approach corrected existing overloaded panels and MCCs and provided for limited future growth in UNMH’s central plant. We used our most cost effective resources to perform the study and design. When doing fieldwork, we spend additional time prior to the visit in planning all the information that must be obtained and during the visit to make sure that we obtain all the required information. LEI prepared its proposal based on connecting to existing electrical equipment. However, it was necessary to design new electrical services in order to feed the chiller and related equipment. LEI did the design for the original fee even though there was substantial additional design work required by having to design new electrical service both for the chiller and the auxiliary equipment.